The Umbelliferae comprise about 2000 species of mainly herbaceous plants, but sometimes shrubs, within about 250 genera. Many species are cultivated for food providing edible roots (e.g. Arracacia xanthirhiza Bancr., arracacha), herbs (e.g. Petroselinum crispum Nym., parsley), leaf vegetables (e.g. Foeniculum vulgare Mill., fennel) and oils (e.g. fennel), whilst some species are cultivated for medicinal products (e.g. Conium spp.). The fruits are schizocarps containing two (or sometimes more) mericarps (see Chapter 3, Volume I). Seed storage behaviour is orthodox.
SEED DORMANCY AND GERMINATION
B.R. Atwater classifies seed morphology as endospermic seeds with axillary linear embryos (see Table 17.1, Chapter 17). The embryos are comparatively under developed and within an accession may vary considerably in maturity (in essence embryo size). Moreover, a high proportion of seed-like structures may be empty: see Chapter 8, Volume I, for methods of determining the empty seed fraction.
In addition to treatments intended to break dormancy (which can be a considerable problem), other treatments (e.g. "hardening" - i.e. alternate wetting and drying or pre-treatment with a polyethyleneglycol solution) are often applied to seeds destined for field sowings in an attempt to further the development of comparatively under-developed embryos prior to exposure to the harsh, competitive, field environment. In general light, low constant temperatures (or sometimes pre-chilling) and gibberellin treatments tend to promote germination.
Detailed information on seed dormancy and germination is provided in this chapter for the genera Anethum, Apium, Carum, Coriandrum, Cuminum, Daucus, Foeniculum (including synonyms within Anethum), Pastinaca, and Petroselinum (including synonyms within Apium). A summary of recommended germination test procedures and dormancy-breaking treatments for other species is provided in Table 72.1. In addition the algorithm below may be helpful in developing suitable germination test procedures for difficult accessions.
RBG Kew Wakehurst Place algorithm
The first step in the algorithm is to test seeds at constant temperatures of 11°C, 16°C, and 21°C, with light applied for 12h/d. If full germination does not occur but a trend in germination response to constant temperatures is observed then test at more extreme constant temperatures. For example, if the proportion of seeds germinating at 11°C is greater than at the two higher temperatures then test a further sample of seeds at a constant temperature of 6°C with light applied for 12h/d.
TABLE 72.1 Summary of germination test recommendations for species within the Umbelliferae
|
Species and Authority |
Substrate |
Temperature |
Duration |
Additional directions |
Source |
|
Angelica archangelica L. |
TP; BP |
20°/30°C |
28d |
light, pre-chill |
ISTA |
|
Anthriscus cerefolium (L.) Hoffm.
|
TP; BP |
20°/30°C |
21d |
|
ISTA |
|
TP |
20°/30°C |
21d |
light |
AOSA |
|
|
Chaerophyllum bulbosum L. |
TP |
20°/30°C |
21d |
light |
Heit |
|
Chaerophyllum tainturieri Hook. & Arn.
|
TP |
15°C |
21d |
light, check for empty seeds |
AOSA |
|
|
15°C |
28d |
potassium nitrate, 0.2% |
Atwater |
|
|
Didiscus caeruleus (R. Grah.) DC. |
TP; BP |
20°C |
21d |
good moisture supply desirable |
AOSA |
|
Eryngium spp. |
|
20°C |
28d |
|
Atwater |
|
Levisticum officinale Koch |
TP; BP |
20°/30°C; 20°C |
21d |
|
ISTA |
|
Pimpinella anisum L.
|
TP; BP |
20°/30°C |
21d |
|
ISTA |
|
BP |
20°/30°C |
14d |
|
AOSA |
|
|
TP |
20°/30°C |
14d |
check for empty seeds |
Heit |
|
|
Pimpinella major (L.) Huds. |
TP; BP |
20°/30°C |
21d |
pre-chill |
ISTA |
|
Pimpinella saxifraga L. |
TP; BP |
20°/30°C |
21d |
|
ISTA |
|
Trachymene coerulea R. Grah. |
|
20°C |
14d |
|
Atwater |
If the second step of the algorithm does not promote full germination then the third step is to pre-chill a further sample of seeds at 6°C for 8w and then test in the most appropriate regime determined from a comparison of the results of steps one and two.
If the third step of the algorithm does not result in full germination then the fourth step is to co-apply 7 x 10-4 M GA3 to the germination test substrate and test in the most appropriate regime determined from a comparison of the results of steps one to three. If the proportion of seeds germinating in step three is significantly greater than the comparable test in step one or two then this fourth step should include the pre-chill treatment.
If full germination has not been promoted, the fifth step of the algorithm is to estimate viability using a tetrazolium test (see Chapter 11, Volume I).
If the result of the tetrazolium test indicates that the failure to achieve full germination is due to the presence of dead seeds and that one of the above regimes promoted the germination of all, or almost all, the viable seeds, then this regime is used for all subsequent germination tests. If, however, the result of the tetrazolium test indicates that dormancy has not been broken by the regimes applied so far in the algorithm, then experiment with modifications to the above regimes. Clues to possible satisfactory dormancy-breaking treatments and promotory germination test environments can be obtained from the information provided for nine genera in this chapter and from Table 72.1.
ANETHUM
|
A. graveolens L. |
dill |
I. Evidence of dormancy
After-ripening seeds of A. graveolens for 7 days at 35°C resulted in loss in dormancy in some seed lots (1) - suggesting that dormancy can be present.
II. Germination regimes for non-dormant seeds
BP; TP: 20°/30°C; 10°/30°C (16h/8h): 21d (ISTA)
BP: 20°/30°C (16h/8h): 21d (AOSA)
III. Unsuccessful dormancy-breaking treatments
Alternating temperatures: 36°/31°C (8h/16h), 16d (3)
IV. Partly-successful dormancy-breaking treatments
Constant temperatures: 20°C, dark, 21d (2); 15°C, light or dark, 21d (2); 10°-12°C (1)
Alternating temperatures: 10°/32°C (1); 20°/30°C (16h/8h), light or dark, 21d (2); 24°/19°C, 21°/16°C, 18°/13°C, 15°/10°C (8h/16h), 16d (3)
Pre-dry: 35°C, 5-7d (1)
V. Successful dormancy-breaking treatments
Pre-chill (ISTA)
Alternating temperatures: 30°/25°C, 33°/28°C, 27°/22°C (8h/16h), 16d (3)
Pre-wash: 3-4d, then pre-dry, 4-8h (3)
VI. Comment
Germination test temperatures (preferably alternating) between 20° and 30°C are required for A. graveolens (2, 3): germination is reduced at temperatures below 15°C (1, 3) - at least in 16 day tests (3). Consequently it is suggested that the ISTA/AOSA germination test procedures are adequate for non-dormant seeds, and possibly also for dormant seeds. The regime 25°/30°C (16h/8h) is a possible alternative to consider. Low germination in certain accessions may be due to a high proportion of embryoless seeds (2): ensure that this is not confounded with either non-viability or dormancy by ascertaining the proportion of embryoless seeds before or after the germination test.
VII. References
1. Franck, W.J. and Wieringa, G. (1928). Artificial drying and low temperature as means employed in obtaining an increase in germination of some vegetable seeds. Proceedings of the Association of Official Seed Analysts, 19, 24-27.
2. Heit, C.E. (1948). Laboratory germination results with herb and drug seed. Proceedings of the Association of Official Seed Analysts, 38, 58-62.
3. Putievsky, E. (1980). Germination studies with seed of caraway, coriander and dill. Seed Science and Technology, 8, 245-254.
APIUM
|
A. graveolens L. var dulce Pers. [A.
dulce Mill.; A. celleri Gaertn.] |
celery |
|
A. graveolens L. var lusitanicum (Mill.)
DC. |
wild celery |
|
A. graveolens L. var rapaceum (Mill.) DC. [A.
rapaceum Mill.] |
celeriac, root celery |
I. Evidence of dormancy
The germination of seeds of Apium spp. is fraught with problems, both for seed testers (21,28) and commercial growers (35,39). As in other umbellifers, empty seeds may be present; about 20% empty seeds is common (15). In addition immature embryos can be particularly dormant (15,42). Differences in the degree of seed dormancy between populations are reported to be correlated with the bolting resistance of the mother plant (37); within a population the degree of dormancy of individual seeds is governed by umbel order (26,38). Dormancy can be induced when the seeds are dried from the imbibed state (2-4) (as would happen if the germination test substrate is allowed to dry out), if the imbibed seeds are exposed to high temperatures during the germination test (6-9,22,29,32), or if seeds are pelleted (40). Strictly speaking in the latter case it is not so much that dormancy is induced, but that the pellet subsequently prevents light from reaching the seeds and breaking dormancy and may also restrict oxygen availability.
II. Germination regimes for non-dormant seeds
A. graveolens
TP: 20°/30°C (16h/8h): 21d (ISTA)
TP: 15°/25°C (16h/8h); 20°C: 21d (AOSA)
III. Unsuccessful dormancy-breaking treatments
A. graveolens var dulce
Alternating temperatures: 15°/35°C in dark (27); 30°/35°C (12h/12h) (29); 5°/35°C, 35°/5°C, 10°/30°C, 35°/22°C (16h/8h) in low light (42); 32°/7°C, 35°/5°C, 5°/35°C (16h/8h) in low light (43)
Light: dark, at 18°C (11,38); dark, above 20°C (3,5,11,20,23,31,32,37,39,40,41,46); light, above 30°C (3,8,19,22,25,28,29,35); far red, 20 min (39)
Potassium nitrate: co-applied, 2x10-2, 10-2 M (24); pre-applied, 6d, 1% plus tribasic potassium phosphate, 1% (26); pre-applied, 5-20d, plus tri-potassium orthophosphate, -10, -15 bars, germinate at 20°C in light (34)
Polyethylene glycol: pre-applied, -12 bars (40); pre-applied, 2-14d, -10 bars (3); pre-applied, 1,2w, -11.7 bars, plus GA3, 50 ppm, germinate at 25°C in light (25)
Sodium hypochlorite: pre-applied, 2h, 5.25% (26); pre-applied, 2h, 0.5-2%, germinate at 20°/30°C (16h/8h) in dark (35)
Mercuric chloride: (22)
Ether: (22)
Pre-soak: then ether (22); 5°C, 48h, then pre-dry, germinate at 22°C in dark (46)
Zeatin: co-applied, 10-7 -10-4 M, with or without GA4/7' 2x10-5 M (1,5)
Zeatin riboside: co-applied, 10-7 -10-4 M, with or without GA4/7' 2x10-5 M (1,5)
N -Benzyladenine: co-applied, 10-5 -10-4 M (41); co-applied, 10-5 M (4)
6-Benzylaminopurine: co-applied, 10-7 -10-4 M (1,5); co-applied, 10-5 -10-4 M (41)
Dihydrozeatin: co-applied, 10-7 -10-4 M, with or without GA4/7' 2x10-5 M (1,5)
Cytokinin: co-applied, 10-7 -5x10-6 M, with or without GA4/7, 2x10-5 M (1,5)
6-Aminopurine: co-applied, 10-7 -10-4 M, plus GA4/7, 2x10-5 M (5)
Kinetin: co-applied, 10-7 -5x10-6 M, plus GA4/7, 2x10-5 M (5); co-applied, 10-5 -10-4 M (41)
Kinetin riboside: co-applied, 10-7 -5x10-6 M, plus GA4/7, 2x10-5 M (5)
N6 -Methyladenine: co-applied, 10-5 -10-4 M, with or without GA4/7, 2x10-4 M (41)
Adenine: co-applied, 10-5 -10-4 M, with or without GA4/7, 2x10-4 M (41)
Ethephon: co-applied, 3.5x10-3 M (41)
Daminozide: co-applied, 7.5x10-3 M (41)
Citric acid: co-applied, 5x10-3 M (30)
Tartaric acid: co-applied, 5x10-3 M (30)
Ascorbic acid: co-applied, 5x10-3 M (30)
Succinic acid: co-applied, 10-2 M (30)
GA3: co-applied, 100 ppm, at 25°C in dark (31)
GA4/7: co-applied, 10-5 M (30); co-applied, 100 ppm, at 25°C in dark (31); pre-applied, 48h, 5°C, 1000 ppm plus daminozide, 4000 ppm, then pre-dry, germinate at 22°C in dark (46); pre-applied, 48h, 5°C, 1000 ppm plus ethephon, 1000 ppm, then pre-dry, germinate at 22°C in dark (46)
A. graveolens var lusitanicum
Light: dark, at 20°C (32); light, 5 min/d, 1-6d, at 5°C (32); far red, 5 min, at 20°C (32)
A. graveolens var rapaceum
Light: dark, at 10°C, 20°C (32); light, 5-30 min, at 10°C, 20°C (32)
Pre-soak: 5°C, 48h, then pre-dry, germinate at 22°C in dark (46)
GA4/7: pre-applied, 48h, 5°C, 1000 ppm plus daminozide, 4000 ppm, then pre-dry, germinate at 22°C in dark (46); pre-applied, 48h, 5°C, 1000 ppm plus ethephon, 1000 ppm, then pre-dry, germinate at 22°C in dark (46)
IV. Partly-successful dormancy-breaking treatments
A. graveolens var dulce
Constant temperatures: 20°C in light (19,20,28,35); 22°C in light (3); 25°C in continuous light (31,32); 13°-18°C in dark (40,41); 10°-15°C in low light (42,43); 5°C in continuous light (32); 10°-22°C (24); 10°C, 20°C, light, red, 5-30 min (32)
Alternating temperatures: 30°/20°C (16h/8h) (15); 10°/15°-38°C, 15°/22°-32°C, 5°/15°-29°C (18h/6h) (24); 20°/30°C, 10°/20°C (16h/8h) in light (28); 20°/35°C, 25°/35°C (12h/12h) (29); 20°/10°C, 30°/10°C, 30°/20°C (12h/12h) (32); 21°/10°C (16-22h/2-8h) in dark (35); 30°/10°C, 25°/15°C, 15°/25°C, 5°-15°/22°C, 25°-30°/22°C (16h/8h) in low light (42); 12°/27°C, 27°/12°C, 10°/30°C, 15°/25°C, 25°/15°C, 30°/10°C (16h/8h) in low light (43); 20°/30°C in light or dark (44)
Pre-chill: 0°C (22)
Warm stratification: 32°C, 3d in dark, then pre-dry (3,4,8)
Pre-soak: 5°C, 48h, then pre-dry, germinate at 17°C in dark or 22°C in light, continuous (46)
Light: red (22); 5 min, at 20°C (32); 5-10 min, at 22°C (39); 1 min/d, at 22°C (39); green, 5 min/8h (32); far red, 10-30 min, at 20°C (32)
6-Benzylaminopurine: co-applied, 10-7-5x10-6, 5x10-5 M, plus GA4/7' 2x10-5 M (5); co-applied, 10-6-10-4 M, plus GA4/7, 2x10-5 M (5)
N6-Benzyladenine: co-applied, 10-6, 3x10-6, 10-5, 3x10-5 M (1,9); co-applied, 20 ppm, at 25°C in dark (31); co-applied, 10 ppm, with or without GA4, 50 ppm, at 25°C, 30°C in light (25); co-applied, 10-5-10-4 M, plus GA4/7, 2x10-4 M (41); co-applied, 10 ppm, plus GA4/7, 50 ppm (31); pre-applied, 48h, 5x10-4 M in dichloromethane, germinate at 30°/35°C, 25°/35°C, 20°/35°C (16h/8h) in light (29); pre-applied, 48h, 5x10-4 M, plus ethephon, 1000 ppm, germinate at 30°/35°C, 25°/35°C (16h/8h) in light (29); pre-applied, 48h, 5x10-4 M, plus GA4/7, 3x10-3 M in dichloromethane, germinate at 30°/35°C, 25°/35°C (16h/8h) in light (29)
Cytokinin: co-applied, 10-5, 5x10-5 M, plus GA4/7, 2x10-5 M (5)
6-Aminopurine: co-applied, 10-5, 5x10-5 M, plus GA4/7, 2x10-5 M (5)
6-Benzylaminopurine: co-applied, 10-6, 5x10-6, 5x10-5, 10-4 M, plus GA4/7, 2x10-5 M (5,41)
1-3-Chloropthalimido-cyclohexanecarboxamide: co-applied, 10-1000 ppm, germinate at 22°C, dark (47); co-applied, 10-1000 ppm, plus GA4/7, 66 ppm, germinate at 22°C, dark (47)
1-1-Cyclohexene-1,2-dicarboximido-cyclohexane carboxamide: co-applied, 50-1000 ppm, germinate at 22°C, dark (47); co-applied, 50-1000 ppm, plus GA4/7, 66 ppm, germinate at 22°C, dark (47) N4-Pyridyl-N'-phenylurea: co-applied, 20 ppm, plus 1-3-chloropthalimido-cyclohexanecarboxamide, 5-1000 ppm, germinate at 22°C, dark (47); co-applied, 20 ppm, plus 1-1-cyclohexane-1,2-dicarboximido-cyclohexane carboxamide, 5-1000 ppm, germinate at 22°C, dark (47)
N-Dimethylaminosuccinamic acid: co-applied, 2000 ppm (31); co-applied, 1000 ppm, plus GA4/7, 50 ppm (31)
N-Phenyl pyridyl urea: co-applied, 10-4 M (41) Daminozide: co-applied, 7.5x10-3 M, plus GA4/7, 2x10-4 M (41)
Hydroxylamine hydrochloride: co-applied, 10-3 M, plus GA4/7, 2x10-4 M (41)
Cyclohexanediaminetetraacetic acid: co-applied, 10-3 M, plus GA4/7, 2x10-4 M (41)
Sodium ethylenediaminetetraacetate: co-applied, 10-3 M (41); co-applied, 10-3 M, plus GA4/7, 2x10-4 M (41)
Kinetin: co-applied, 10-5, 5x10-5 M, plus GA4/7, 2x10-5 M (5); co-applied, 10-5 -10-4 M, plus GA4/7, 2x10-4 M (41)
Kinetin riboside: co-applied, 10-5, 5x10-5 M, plus GA4/7, 2x10-5 M (5)
Citric acid: co-applied, 5x10-3 M, plus GA4/7, 10-5 M (30)
Tartaric acid: co-applied, 5x10-3 M, plus GA4/7, 10-5 M (30)
Ascorbic acid: co-applied, 5x10-3 M, plus GA4/7, 10-5 M (30)
Succinic acid: co-applied, 5x10-3 M, plus GA4/7, 10-5 M (30)
GA4: co-applied, 50 ppm, at 25°C, 30°C in light (25)
GA4/7: co-applied, 10-5 -10-3 M (30,41); co-applied, 2x10-4 M (37,38,39); co-applied, 330 ppm (47); pre-applied, 48h, 3x10-3 M in dichloromethane, with or without benzyladenine, 5x10-4 M (29); pre-applied, 48h, 3x10-3 M in dichloromethane, plus ethephon, 1000 ppm (29); co-applied, 2x10-4 M, plus daminozide, 7.5x10-3 M (38); pre-applied, 48h, 5°C, 1000 ppm plus daminozide, 4000 ppm, then pre-dry, germinate at 17°C in dark or 22°C in light, continuous (46); pre-applied, 48h, 5°C, 1000 ppm plus ethephon, 1000 ppm, then pre-dry, germinate at 17°C in dark or 22°C in light, continuous (46)
Sodium hypochlorite: pre-applied, 2h, 1%, germinate at 10°C, dark (35)
Ethephon: pre-applied, 48h, 1000 ppm (29)
Polyethylene glycol: pre-applied, 14d, -10 bars, at 18°C (33); pre-applied, 27d, -10 bars, at 10°C in light (12); pre-applied, 7,14d, -11.7 bars, plus benzyladenine, 10 ppm, at 20°C in dark (25); pre-applied, 7,14d, -11.7 bars, plus benzyladenine, 10 ppm, plus GA3, 50 ppm (25)
Potassium nitrate: pre-applied, 14-35d, plus tri-potassium orthophosphate, -10, -12.5, -15 bars (34)
A. graveolens var lusitanicum
Constant temperatures: 5°C in continuous light (32); 10°C, 20°C, 5-30 min/d red light (32)
Alternating temperatures: 30°/20°C, 30°/10°C, 20°/10°C (12h/12h) (32)
Light: red, 5 min/d (32); green, 5 min/d (32)
A. graveolens var rapaceum
Constant temperatures: 10°C, 20°C, light, 10-30 min/d (32); 17°C, dark (46); 22°C, light, continuous (46)
Alternating temperatures: 20°/10°C (12h/12h) (32)
Pre-soak: 5°C, 48h, then pre-dry, germinate at 17°C in dark or 22°C in light, continuous (46)
GA4/7: pre-applied, 48h, 5°C, 1000 ppm plus daminozide, 4000 ppm, then pre-dry, germinate at 17°C in dark or 22°C in light (46); pre-applied, 48h, 5°C, 1000 ppm plus ethephon 1000 ppm, then pre-dry, germinate at 17°C in dark or 22°C in light (46)
V. Successful dormancy-breaking treatments
A. graveolens
Pre-chill, Potassium nitrate (ISTA)
Light (AOSA)
A. graveolens var dulce
Alternating temperatures: 22°/29°C (16h/8h) in light, 8h/d (17); 15°/22°C, 22°/29°C (16h/8h) in light, 8h/d (18); 15°/20°C, 15°/25°C, 15°/30°C (16.5h/7.5h) in light (19); 20°/30°C (18h/6h) in light (20); 15°/35°C in light (27); 21°/10°C (2-8h/16-22h) in dark (35); 15°/25°C (16h/8h) (44); 10°/25°C in dark or light (22)
Pre-chill: 10°C, 5d, germinate at 20°/30°C (16h/8h) (16) Warm stratification: 20°C, 3d, then pre-chill, 1°C, 11d (14); 20°C, 17d, dark, germinate at 20°C in light (35)
Light: continuous, at 10°C, 17°C (2); continuous, 5x10-6 mol m-2 s-1, at 17°C (3,4,6,7,8,38); continuous, at 20°C (23); continuous, at 22°C (37,41); continuous, at 5°-20°C (32); 8h/d, at 9°-17°C (10); 8h/d, at 8°C, 15°C (17); 8h/d, at 8°-22°C (18); 8h/d, 5 W m-2, at 8.5°C (45); at 15°C (19,22); at 15°C, 20°C (25); red, 5 min/d, 6d, at 15°C (32); red, continuous, at 22°C (39); dark, at 15°C (25); dark, at 10°C (35); dark, at 14°-16°C (11); dark or light, at 15°C (22)
GA4/7: co-applied, 2x10-4 M, plus benzyladenine, 10-5 M (1,38); pre-applied, 48h, 3x10-3 M, plus benzyladenine, 5x10-4 M (29); co-applied, 2x10-5, 2x10-4 M, plus cytokinin, 10-4 M (5,36,39); co-applied, 2x10-5 M, plus benzylaminopurine, 10-5 M (5); co-applied, 2x10-5 M, plus aminopurine, 10-4 M (5); co-applied, 2x10-5 M, plus 6-benzylaminopurine, 10-5 M (5,41); co-applied, 2x10-5, 10-5 M, plus kinetin, 10-4 M (5); co-applied, 2x10-5 M, plus kinetin riboside, 10-4 M (5); co-applied, 2x10-4 M, plus N-phenylpyridyl urea, 10-4 M (41); co-applied, 2x10-4 M, plus ethephon, 3.5x10-3 M (41); co-applied, 1000 ppm, plus ethephon, 1000 ppm, germinate at 14°-16°C, dark (11); pre-applied, 3x10-3 M, plus ethephon, 1000 ppm, germinate at 20°/35°C in light (29); pre-applied, 48h, 5°C in light, continuous, plus ethephon, 1000 ppm, then polyethylene glycol, pre-applied, 14d, -15 bar, 15°C in light, continuous, germinate at 15°-19°C, dark (11); pre-applied 48h, 5°C, 1000 ppm, plus ethephon, 1000 ppm (1,40); pre-applied 48h, 5°C, 1000 ppm, plus daminozide, 4000 ppm (1,40)
Sodium hypochlorite: pre-applied, 2h, 1, 2%, germinate at 19°-22°C in light or 10°/21°C (16h/8h) in dark (35)
Pre-soak: 0.5,3h, germinate at 22°C in light (41)
Polyethylene glycol: pre-applied, 7,14d, -11.7 bars, 15°C in light, germinate at 20°C (25); pre-applied, 5,20d, -10, -15 bars, germinate at 20°C in light (34); pre-applied, 14d, -15 bar, 15°C in light, continuous, plus GA4/7, 1000 ppm, plus ethephon, 1000 ppm, germinate at 14°-18°C, dark (11); pre-applied, 14d, -15 bar, 15°C in light, continuous, then GA4/7, pre-applied, 48h, 1000 ppm, plus ethephon, 1000 ppm, 5°C in light, continuous, germinate at 15°C, dark (11)
A. graveolens var lusitanicum
Constant temperatures: 15°C, 20°C in continuous light (32)
VI. Comment
It is essential to provide light (2,3,20,23,24,27,28,32,36,38) at either a low constant temperature (2-4,6-8,10,17,19,22,25,32,35,38,45) or - preferably - in an alternating temperature regime (17-20,27,35,44) and to maintain a moist substratum (13,24) in order to promote the germination of seeds of Apium spp. Alternating temperature regimes of 15°/22°C (18), 10°/20°C (28) or 12°-15°/22°-25°C (42,43) are more effective in promoting germination than either 20°/30°C (all 16h/8h in light) or 15°C or 20°C in light (the latter being the more suitable of constant temperature germination test regimes). It is suggested that gene banks use the regime 15°/25°C (16h/8h) with light applied during the period spent at the upper temperature during each diurnal cycle. If it is necessary to use a constant temperature germination test regime then use 15°C. For the most dormant seeds it may be necessary to provide an additional stimulus with 2x10-5 M, GA4/7 plus 10-4 M cytokinin, co-applied.
VII. References
1. Biddington, N.L. (1978). Growth regulator interactions in the control of (celery) seed germination. In The effect of interactions between growth regulators on plant growth and yield, pp. 29-36. British Plant Growth Regulator Group, Monograph No. 2, London.
2. Biddington, N.L. (1981). Thermodormancy and the prevention of desiccation injury in celery seeds. Annals of Applied Biology, 98, 558-562.
3. Biddington, N.L., Brocklehurst, P.A., Dearman, A.S. and Dearman, J. (1982). The prevention of dehydration injury in celery seeds by polytheylene glycol, abscissic acid, dark and high temperature. Physiologia Plantarum, 55, 407-410.
4. Biddington, N.L., Dearman, A.S. and Thomas, T.H. (1982). Effects of temperature and drying rate during dehydration of celery seeds on germination, leakage and response to gibberellin and cytokinin. Physiologia Plantarum, 54, 75-78.
5. Biddington, N.L. and Thomas, T.H. (1976). Influence of different cytokinins on the germination of lettuce (Lactuca sativa) and celery (Apium graveolens) seeds. Physiologia Plantarum, 37, 12-16.
6. Biddington, N.L. and Thomas, T.H. (1978). Thermodormancy in celery seeds and its removal by cytokinins and gibberellins. Physiologia Plantarum, 42, 401-405.
7. Biddington, N.L. and Thomas, T.H. (1979). Residual effects of high temperature pre-treatments on the germination of celery seeds (Apium graveolens). Physiologia Plantarum, 47, 211-214.
8. Biddington, N.L., Thomas, T.H. and Dearman, A.S. (1980). The promotive effect on subsequent germination of treating imbibed celery seeds with high temperature before or during drying. Plant Cell and Environment, 3, 461-465.
9. Biddington, N.L., Thomas, T.H. and Dearman, A.S. (1980). The effect of temperature on the germination-promoting activities of cytokinin and gibberellin applied to celery seeds (Apium graveolens). Physiologia Plantarum, 49, 68-70.
10. Bierhuizen, J.F. and Wagenvoort, W.A. (1974). Some aspects of seed germination in vegetables. 1. The determination and application of heat sums and minimum temperature for germination. Scientia Horticulturae, 2, 213-219.
11. Brocklehurst, P.A., Rankin, W.E.F. and Thomas, T.H. (1982/1983). Stimulation of celery seed germination and seedling growth with combined ethephon, gibberellin and polyethylene glycol seed treatments. Plant Growth Regulation, 1, 195-202.
12. Darby, R.J. Salter, P.J. and Whitlock, A.J. (1979). Effects of osmotic treatment and pre-germination of celery seeds on seedling emergence. Experimental Horticulture, 31, 10-20.
13. Doneen, L.D. and MacGillivray, J.H. (1943). Germination (emergence) of vegetable seeds as affected by different soil moisture conditions. Plant Physiology, 18, 524-529.
14. Finch-Savage, W.E. and Cox, C.J. (1982). A cold-treatment technique to improve the germination of vegetable seeds prior to fluid drilling. Scientia Horticulturae, 16, 301-311.
15. Flemion, F. and Uhlmann, G. (1946). Further studies of embryoless seeds in the Umbelliferae. Contributions from the Boyce Thompson Institute, 14, 283-293.
16. Fornerod, C. (1975). Remarques sur la germination des semences potagères en laboratoire. Revue Horticole Suisse, 48, 6-9.
17. Guy, R. (1980). Quelques exemples des effects de la temperature sur la germination des plantes potagères. Revue Suisse de Viticulture, d'Arboriculture et d'Horticulture, 12, 35-37.
18. Guy, R. (1981). Influence de la temperature sur la dureé de germination des semences de dix espèces potagères. Revue Suisse de Viticulture, d'Arboriculture et d'Horticulture, 13, 219-225.
19. Harrington, G.T. (1923). Use of alternating temperatures in the germination of seeds. Journal of Agricultural Research, 23, 295-332.
20. Hicks, G. and Key, S. (1898). Additional notes on seed testing. U.S. Department of Agriculture, Yearbook 1897, 441-452.
21. Hopkins, E.F. (1926). Studies in the germination of celery seed. Proceedings of the Association of Official Seed Analysts, 18, 47-49.
22. Hopkins, E.F. (1928). Further studies of celery seed germination. Proceedings of the Association of Official Seed Analysts, 20, 69-70.
23. Kinzel, W. (1908). Lichtkeimung. Einige bestätigende und ergänzende Bemerkungen zu den vorläfigen Mitteilungen von 1907 und 1908. Bericht der Deutschen Botanischen Gesellschaft, 26a, 631-645.
24. Morinaga, T. (1926). Effect of alternating temperatures upon the germination of seeds. American Journal of Botany, 13, 141-158.
25. Nakamura, S., Teranishi, T. and Aoki, M. (1982). [Promoting effect of polyethylene glycol on the germination of celery and spinach seeds.] Journal of the Japanese Society for Horticultural Science, 50, 461-467.
26. Nettles, V.F. and Poe, L.N. (1973). Germination studies with celery seed. Proceedings of the Florida State Horticultural Society, 86, 172-175.
27. Niethammet-Prag, A. von (1934). Licht, Dunkelheit und Strahlung als Faktoren bei der Samen-keimung. Tabulae Biologicae (Periodicae), 10, 45-77.
28. Nutile, G.E. and Canfield, A.P. (1950). Effect of temperature and light on the germination of celery seed. Newsletter of the Association of Official Seed Analysts, 24, 20-22.
29. Palevitch, D. and Thomas, T.H. (1974). Thermodormancy release of celery seed by gibberellins, 6-benzylaminopurine, and ethephon applied in organic solvent to dry seeds. Journal of Experimental Botany, 25, 981-986.
30. Palevitch, D. and Thomas, T.H. (1976). Enhancement by low pH of gibberellin effects on dormant celery seeds and embryoless half-seeds of barley. Physiologia Plantarum, 37, 247-252.
31. Palevitch, D., Thomas, T.H. and Austin, R.B. (1971). Dormancy-release of celery seed by a growth retardant, N-dimethylaminosucciamic acid (Alar). Planta, 100, 370-372.
32. Pressman, E., Negbi, M., Sachs, M. and Jacobsen, J.V. (1977). Varietal differences in light requirements for germination of celery (Apium graveolens L.) seeds and the effects of thermal and solute stress. Australian Journal of Plant Physiology, 4, 821-831.
33. Rennick, G.A. and Tiernan, P.I. (1978). Some effects of osmopriming on germination, growth and yield of celery (Apium graveolens). Seed Science and Technology, 6, 695-700.
34. Salter, P.J. and Darby, R.J. (1976). Synchronization of germination of celery seeds. Annals of Applied Biology, 84, 415-424.
35. Taylor, C.A. (1949). Some factors affecting germination of celery seed. Plant Physiology, 24, 93-102.
36. Thomas, T.H. (1976). The role of growth in the control of seed germination and seedling establishment. Journal of the Science of Food and Agriculture, 27, 794.
37. Thomas, T.H. (1978). Relationship between bolting-resistance and seed dormancy of different celery cultivars. Scientia Horticulturae, 9, 311-316.
38. Thomas, T.H., Biddington, N.L. and O'Toole, D.F. (1979). Relationship between position on the parent plant and dormancy characteristics of seeds of three cultivars of celery (Apium graveolens). Physiologia Plantarum, 45, 492-496.
39. Thomas, T.H., Biddington, N.L. and Palevitch, D. (1978). The role of cytokinins in the phytochrome-mediated germination of dormant imbibed celery (Apium graveolens) seeds. Photochemistry and Photobiology, 27, 231-236.
40. Thomas, T.H., Biddington, N.L. and Palevitch, D. (1978). Improving the performance of pelleted celery seeds with growth regulator treatments. Acta Horticulturae, 83, 235-244.
41. Thomas, T.H., Palevitch, D., Biddington, N.L. and Austin, R.B. (1975). Growth regulators and the phytochrome-mediated dormancy of celery seeds. Physiologia Plantarum, 35, 101-106.
42. Thompson, P.A. (1974). Germination of celery (Apium graveolens L.) in response to fluctuating temperatures. Journal of Experimental Botany, 25, 156-163.
43. Thompson, P.A. (1974). Effects of fluctuating temperatures on germination. Journal of Experimental Botany, 25, 164-175.
44. Toole, E.H. and Toole, V.K. (1951). Methods of testing celery seed in relation to seed storage problems. Proceedings of the Association of Official Seed Analysts, 41, 62-65.
45. Wagenvoort, W.A., Boot, A. and Bierhuizen, J.F. (1981). Optimum temperature range for germination of vegetable seeds. Gartenbauwissenschaft, 46, 97-101.
46. Thomas, T.H. (1983). Stimulation of celeriac and celery seed germination by growth regulator seed soaks. Seed Science and Technology, 11, 301-305.
47. Thomas, T.H. (1984). Gibberellin-like stimulation of celery (Apium graveolens L.) seed germination by N-substituted phthalimides. Scientia Horticulturae, 23, 113-117.
CARUM
|
C. carvi L. |
caraway |
I. Evidence of dormancy
Seeds of C. carvi can show considerable dormancy (2,3,6), which is reportedly due to endogeneous germination inhibitors (3,6).
II. Germination regimes for non-dormant seeds
TP: 20°/30°C (16h/8h): 21d (ISTA)
TP: 20°/30°C (16h/8h): 14d (AOSA)
Alternating temperatures: 20°/30°C (16h/8h), light, 14d (1)
III. Unsuccessful dormancy-breaking treatments
Alternating temperatures: 27°/22°C, 30°/25°C, 33°/28°C, 36°/31°C (8h/16h) (5)
IV. Partly-successful dormancy-breaking treatments
Alternating temperatures: 21°/16°C, 24°/19°C (8h/16h) (5); 20°/30°C (16h/8h), light (6)
V. Successful dormancy-breaking treatments
Light (AOSA)
Constant temperatures: 10°C (4)
Alternating temperatures: 15°/10°C, 18°/13°C (8h/16h) (5)
Pre-chill: 4°C (2,3)
Pre-soak: 6d, 15°/10°C (8h/16h), then pre-dry, 15°/10°C (8h/16h), germinate at 15°/10°C (8h/16h) (5)
VI. Comment
A 21-day test in the alternating temperature regime prescribed by ISTA and AOSA is not entirely adequate for either freshly harvested or 4 year old seed lots of C. carvi (6): for non-dormant accessions it is necessary to extend the test duration to at least 35 days (6). However, it would be preferable to test both non-dormant and dormant accessions at lower temperatures (4,5). Whilst testing at 4°C can be satisfactory (2,3), an alternating temperature regime of 15°/10°C (8h/16h) (5) or a constant temperature regime of 10°C (4) are suggested since tests in these regimes can be concluded sooner than those at 4°C.
VII. References
1. Heit, C.E. (1948). Laboratory germination results with herb and drug seed. Proceedings of the Association of Official Seed Analysts, 38, 58-62.
2. Hradilík, J. and Císaàová, H. (1975). [Studies on the dormancy of caraway (Carum carvi) achenes.] Rostlinná Vy6roba, 21, 351-364. (From Horticultural Abstracts, 1976, 46, 7026.)
3. Hradilík, J. and Fiserová, H. (1980). [The role of abscisic acid in caraway (Carum carvi) seed dormancy.] Acta Universitatis Agriculturae, Brno, A, 28, 39-64. (From Horticultural Abstracts, 1982, 52, 4161.)
4. Putievsky, E. (1977). [Tests on caraway seed germination.] Hassadeh, 57, 1413-1415. (From Seed Abstracts, 1978, 1, 67.)
5. Putievsky, E. (1980). Germination studies with seed of caraway, coriander and dill. Seed Science and Technology, 8, 245-254.
6. Weisaeth, G. (1978). [Germination capacity of Carum carvi seed in relation to the life cycle of caraway plants.] Seed Science and Technology, 6, 685-693.
CORIANDRUM
|
C. sativum L. |
coriander |
I. Evidence of dormancy
Delayed germination of the seeds is a frequent problem for growers (3) and freshly harvested seeds show considerable dormancy (A).
II. Germination regimes for non-dormant seeds
TP; BP: 20°C; 20°/30°C (16h/8h): 21d (ISTA)
BP: 15°C: 21d (AOSA)
Constant temperatures: 15°C (2)
III. Unsuccessful dormancy-breaking treatments
Alternating temperatures: 36°/31°C (8h/16h) (3)
IV. Partly-successful dormancy-breaking treatments
Alternating temperatures: 27°/22°C, 24°/19°C, 21°/16°C, 18°/13°C, 15°/10°C, 30°/25°C (8h/16h) (3); 20°/30°C (16h/8h) (1)
Pre-chill: 8°-12°C, 7d, germinate at 20°/30°C (16h/8h) (1)
Pre-soak: 3-4d, then pre-dry, 8h, germinate at 27°/22°C (8h/16h) (3)
V. Successful dormancy-breaking treatments
Constant temperatures: 15°C (2)
VI. Comment
Coriander seed germination is severely reduced at temperatures above 30°C or below 10°C (3). Within those alternating temperature regimes listed above as partly-successful dormancy-breaking treatments, the most suitable regime for testing coriander seeds for germination is 27°/22°C (8h/16h) (3). It is suggested that either this regime or that recommended by the ISTA - 20°/30°C (16h/8h) - be used for germination tests, but note that neither regime alone may result in full germination. For example, testing freshly harvested seeds in an alternating temperature regime of 20°/30°C (16h/8h) with continuous light resulted in a very shallow germination progress curve with seeds continuing to germinate after 10 weeks in test (A): cumulative germination at 10 weeks was only 40% (A). Although a constant temperature of 15°C has been recommended (2, AOSA) we suspect that the use of this regime will be less satisfactory than either of the two above alternating temperature regimes since germination in 20-day tests at either 18°/13°C (8h/16h) or 15°/10°C (8h/16h) - where the mean temperature is not too dissimilar to 15°C - was far lower than at 27°/22°C (8h/16h) (3). This may explain why the previous ISTA recommendation (1976 rules) to test dormant coriander seeds at 10°/20°C (16h/8h) has been deleted from the current rules. Further dormancy-breaking agents which are likely to be effective in promoting germination include pre-chilling, gibberellins and light. Because of the problem of embryoless seeds, dissection of non-germinated seeds at the end of germination tests is advised.
VII. References
1. Esnin, S.A., Myakota, B.V. and Sokolova, L.F. (1978). [A method for germinating coriander seeds.] Selektsiya i Semenovodstvo, 3, 56. (From Seed Abstracts, 1979, 2, 941.)
2. Heit, C.E. (1948). Laboratory germination results with herb and drug seed. Proceedings of the Association of Official Seed Analysts, 38, 58-62.
3. Putievsky, E. (1980). Germination studies with seed of caraway, coriander and dill. Seed Science and Technology, 8, 245-254.
CUMINUM
|
C. cyminum L. [C. odorum Salisb.] |
cumin |
I. Evidence of dormancy
Low and irregular germination of cumin seeds is a problem for growers (5).
II. Germination regimes for non-dormant seeds
TP: 20°/30°C (16h/8h): 14d (ISTA,AOSA)
Alternating temperatures: 20°/30°C (16h/8h) in light (3)
III. Unsuccessful dormancy-breaking treatments
Indoleacetic acid: (4)
GA3: (4)
Kinetin: (4)
Ethephon: (4)
IV. Partly-successful dormancy-breaking treatments
GA3: pre-applied, 24h, 25-100 ppm (5)
Naphthaleneacetic acid: pre-applied, 24h, 10 ppm (2)
1-Naphthyl acetic acid: pre-applied, 24h, 25, 50 ppm (5)
2-Naphthoxyacetic acid: pre-applied, 24h, 25-100 ppm (5)
Maleic hydrazide: pre-applied, 24h, 25-100 ppm (5)
Indolyl-3-acetic acid: pre-applied, 24h, 10 ppm (2); pre-applied, 24h, 25, 50 ppm (5)
Indolyl-3-butyricum acetic acid: pre-applied, 24h, 25-100 ppm (5)
2,4,5-Trichlorophenoxy acetic acid: pre-applied, 24h, 50 ppm (5)
2,4-Dichlorophenoxyacetic acid: pre-applied, 24h, 25, 50 ppm (5)
Colchicine: pre-applied, 24h, 25, 50 ppm (5)
V. Successful dormancy-breaking treatments
Pre-wash: 24h, germinate at 18°C (1)
Indolyl-3-acetic acid: pre-applied, 24h, 100 ppm (5)
VI. Comment
It is suggested that cumin seeds be tested for germination according to the AOSA and ISTA rules: that is in an alternating temperature regime of 20°/30°C (16h/8h).
VII. References
1. Chaturvedi, S.N. and Muralia, R.N. (1975). Germination inhibitors in some Umbellifer seeds. Annals of Botany, 39, 1125-1129.
2. Gandhi, S.M. and Bhatnagar, M.P. (1961). Effect of certain hormones on germination, flowering, fruiting, branching and yield of cumin (Cuminum cyminum L.). Journal of the Indian Botanical Society, 40, 628-634.
3. Heit, C.E. (1948). Laboratory germination results with herb and drug seed. Proceedings of the Association of Official Seed Analysts, 38, 58-62.
4. Hradlík, J. and Císaróvá, H. (1975). The role of abscisic acid (ABA) in achenes of dormant cumin. Acta Universitatis Agriculturae, Brno, A, 23, 747-753. (From Horticultural Abstracts, 1978, 48, 5855.)
5. Sankhla, H.C. and Mathur, R.L. (1968). Effects of growth-regulating substances, inorganic fertilizers, oil cakes and soil pH on germination of cumin (Cuminum cyminum L.) seeds. Indian Journal of Agricultural Science, 38, 270-274.
DAUCUS
|
D. carota L. var carota |
wild carrot, Queen Anne's lace |
|
D. carota L. var sativus (Hoffm.) Thell. [D.
carota L. var sativa DC.] |
carrot |
|
D. pusillux Michx. |
|
I. Evidence of dormancy
Freshly harvested seeds of the cultivated carrot (D. carota var sativus) can show considerable dormancy (1,5,6,9-11,17,22,26,31,33,37,38) and as a result germination tests may have to be continued for up to 32 (26), 44 (33), 100 (11) or 150 days (5). Although dormancy is usually thought to be the result of the presence of immature seeds (5,13,17,37), mature seeds can also exhibit dormancy (31,37). At least 3 months' after-ripening is reported to be required to remove dormancy (9,37). Not surprisingly seeds of the wild carrot species (D. carota var carota and D. pusillux) show more pronounced dormancy than seeds of the cultivated species (3,4,8,9,26). For example, seeds of D. pusillux failed to germinate at harvest, and only gave 43% germination after 1 year's after-ripening at room temperature (3,4), whilst seeds of D. carota var carota failed to germinate at all after one year's after-ripening (8).
II. Germination regimes for non-dormant seeds
D. carota
TP; BP: 20°/30°C (16h/8h); 20°C: 14d (ISTA)
BP: 20°/30°C (16h/8h): 14d (AOSA)
Alternating temperatures: 20°/30°C (16h/8h) (14)
III. Unsuccessful dormancy-breaking treatments
D. carota var carota
Constant temperatures: 10°C, continuous light or dark (16)
Alternating temperatures: (8); 0°-12°/40°C (12h/12h) (16); 0°-12°/40°C (12h/12h), 17d, then 21°-28°C, in light (16)
Pre-chill: 6°C (8); 5°C, 14d (9); 10°C, 8d, in light or dark, then 25°C, dark, 8d, then 25°C in light (16); 10°C, 8d, dark, then 40°C, dark, 4d, then 25°C in dark, 4d, then 25°C in light (16)
Warm stratification: 40°C, 17d, dark, germinate at 25°C in light (16)
Light: 16h/d, at 16°C, 19°C (8); dark, at 15°C, 25°C (16)
Pre-soak: (26); 1,3,6w, 6°C (8); 15,30s, at 60°C, 75°C, 90°C (16)
Scarification: sand paper, germinate at 25°C, dark (16); concentrated sulphuric acid, 0.5,1 min (16) pH: 3-8 (8)
Acetic acid: pre-applied, 24h, 10-4-1 M (16)
Butyric acid: pre-applied, 24h, 10-4-1 M (16)
Citric acid: pre-applied, 24h, 10-4-10-1 M (16)
Tartaric acid: pre-applied, 24h, 10-4-10-1 M (16)
Malic acid: pre-applied, 24h, 10-4-10-1 M (16)
Potassium sulphocyanate: pre-applied, 24h, 10-4-10-2 M (16)
Sodium sulphocyanate: pre-applied, 24,28h, 10-4-1 M (16)
Sodium iodide: pre-applied, 24h, 10-4-10-2 M (16)
Sulphuric acid: pre-applied, 24h, 10-4-10-2 M (16)
Potassium sulphate: pre-applied, 24h, 10-4-10-2 M (16)
Ammonium sulphate: pre-applied, 24h, 10-4-1 M (16)
Sodium sulphate: pre-applied, 24h, 10-4-10-2 M (16)
Lithium sulphate: pre-applied, 24h, 10-4-10-2 M (16)
Nickel sulphate: pre-applied, 24h, 10-4-10-2 M (16)
Zinc sulphate: pre-applied, 24h, 10-4-10-2 M (16)
Potassium nitrate: pre-applied, 24h, 10-4-10-2 M (16)
Ammonium nitrate: pre-applied, 24h, 10-4-1 M (16)
Sodium nitrate: pre-applied, 24h, 10-4-1 M (16)
Aluminium nitrate: pre-applied, 24h, 10-4-10-2 M (16)
Cobalt nitrate: pre-applied, 24h, 10-4-10-2 M (16)
Potassium hydroxide: pre-applied, 24h, 10-4-10-2 M (16)
Ammonium hydroxide: pre-applied, 24h, 10-4-10-2 M (16)
Sodium hydroxide: pre-applied, 24h, 10-4-10-1 M (16)
Hydrochloric acid: pre-applied, 24h, 10-4-1 M (16)
D. carota var sativus
Pre-dry: 35°C, 5,7d (15); imbibe/dry (24h/24h), 20°C, 1-3 cycles, germinate at 24°C in light, 10h/d, 5000 lux (2)
Pre-soak: 2-48h, 20°C (26); 10 min, 50°-52°C (31)
Scarification: cut (31); concentrated sulphuric acid, 2 min (31)
Thiourea: pre-applied, 0.1-5% (31)
D. pusillux
Constant temperatures: 20°-35°C (3,4)
Alternating temperatures: 20°/30°C (16h/8h) (3,4)
IV. Partly-successful dormancy-breaking treatments
D. carota var carota
Constant temperatures: 16°-25°C in dark or continuous light (8); 10°-20°C (9); 15°-30°C in continuous light (16); 15°-35°C (25,32)
Alternating temperatures: 20°/10°C (day/night) (9); 20°/30°C, 20°/35°C (16h/8h) in dark (25)
Pre-chill: (26); 0°-12°C, 17d, dark, germinate at 25°C in light (16)
Scarification: sand paper (8)
Removal of seed covering structures: endosperm cap (8)
Oxygen: 40-80% (16)
Hydrogen peroxide: pre-applied, 27h, 5, 20, 50%, in light (16)
Light: 16h/d, at 21°C, 25°C (8); continuous, at 20°-28°C (16); dark, at 16°C (8)
D. carota var sativus
Constant temperatures: 10°-20°C (9,23); 8°C (19); 15°-30°C (21); 10°C (24); 8°-30°C (28); 5°-25°C (35)
Alternating temperatures: 20°/30°C (8h/16h) (13,37); 20°/30°C (16h/8h) (5,11,15,21,26,27,33); 20°/10°C (day/night) (9); 22°/29°C (16h/8h) (20); 15°/20°-35°C, 20°/25°-35°C, 25°/35°C (16.5h/7.5h) (21); 25°/35°C (16h/8h) (37); 16°/5°C (12h/12h) (24); 15°/25°C, 25°/35°C (16h/8h) (27); 4°-11°/25°C, 25°/4°-11°C (16h/8h) (29); 10°/30°C, 15°/20°C (16h/8h) (15)
Pre-chill: 5°C, 14-40d (9)
Removal of seed covering structures: pericarp, hair (1,36)
Pre-soak: 3-4h (36)
Pre-dry: sun (36)
Light: diffuse (1); continuous (17); ultra violet (30)
Dibasic potassium phosphate: pre-applied, 3 cycles, soak/dry, 16h/48h, 10-2 M, germinate at 10°C, 20°C (23)
X-rays: (30)
Acetone: (30)
Polyethylene glycol: pre-applied, 6d, -8.6 bars, 15°C, continuous light, 25x10-5 W cm-2, germinate at 10°C, 10°/5°C, in light (34)
Potassium nitrate: pre-applied, 1-5h, 0.2%, germinate at 20°-25°C in diffuse light (1)
GA3: pre-applied, 3h, 50, 100 ppm, germinate at 20°-25°C in diffuse light (1)
D. pusillux
Constant temperatures: 10°C, 15°C (3,4)
Alternating temperatures: 10°/20°C, 10°/30°C, 15°/30°C (16h/8h) (3,4)
V. Successful dormancy-breaking treatments
D. carota var carota
Alternating temperatures: 15°/30°C (16h/8h) in light (12)
Pre-chill: 5°C, 40-96d (9); 5°C, 3m, germinate in diffuse light (18); 5°C (32)
Hydrogen peroxide: pre-applied, 27h, 10%, in light (16)
D. carota var sativus
Constant temperatures: 10°C in light (6,39); 5°-25°C in light (17); 8°-29°C (19,20); 20°C in light, continuous (39)
Alternating temperatures: 22°/29°C (16h/8h) (19)
Pre-chill: 5°C, 70-96d (9)
Pre-wash: 24h, germinate at 18°C, dark (7)
VI. Comment
It is surprising that light is not prescribed by either the ISTA or the AOSA, since it is essential to provide light during germination tests of seeds of Daucus spp. (1,8,12,16,18). Under normal circumstances there is no advantage of alternating temperature germination test regimes over constant temperature regimes within the range 15°-25°C for the cultivated carrot (9,15,21,24,26,27,29) - although under water stress alternating temperature regimes are beneficial (24). Seeds of the wild carrot species, however, do require alternating temperature regimes for germination in lots where dormancy is pronounced (3,4,9,12,25): 10°/30°C (16h/8h) is suitable for D. pusillux (3,4); and 10°/20°C (9) or 15°/30°C (12) for D. carota var carota. Nevertheless, alternating temperature and light alone are not likely to promote full germination in the more dormant wild carrot seeds; up to 3 months pre-chilling is also likely to be required (9,18).
The following procedures are suggested. For cultivated carrot a pre-treatment with 50 ppm GA3, for 3 hours or so (1), with germination tests at 20°/30°C (16h/8h) with light applied during the 8 hour part of each cycle. It may be necessary to allow this test to continue for six weeks or more. The above can be followed for wild carrot seeds, except that 15°/30°C (16h/8h) should replace 20°/30°C, and a 3 month pre-chill treatment at 3°-5°C will also probably be required. It may be possible to apply a pre-treatment in hydrogen peroxide - 24 hours, 10% (16) - to avoid the requirement of the considerable pre-chill periods.
VII. References
1. Aki, S. (1960). [Effect of gibberellin on breaking the dormancy of Kintoki-carrot seeds.] Technical Bulletin of the Faculty of Agriculture, Kagawa University, 12, 73-77.
2. Austin, R.B., Longden, P.C. and Hutchinson, J. (1969). Some effects of 'hardening' carrot seed. Annals of Botany, 33, 883-895.
3. Barton, L.V. (1936). Germination of some desert seeds. Contributions from the Boyce Thompson Institute, 8, 7-11.
4. Barton, L.V. (1962). The germination of weed seeds. Weeds, 10, 174-182.
5. Borthwick, H.A. (1931). Carrot seed germination. Proceedings of the American Society for Horticultural Science, 28, 310-314.
6. Brocklehurst, P.A. and Dearman, J. (1980). The germination of carrot (Daucus carota L.) seed harvested on two dates: a physiological and biochemical study. Journal of Experimental Botany, 31, 1719-1725.
7. Chaturvedi, S.N. and Muralia, R.N. (1975). Germination imhibitors in some Umbellifer seeds. Annals of Botany, 39, 1125-1129.
8. Dale, H.M. and Harrison, P.J. (1966). Wild carrot seeds: germination and dormancy. Weeds, 4, 201-204.
9. Doust, J.L. and Doust, L.L. (1982). Life-history patterns in British Umbelliferae: a review. Botanical Journal of the Linnean Society, 85, 179-194.
10. Durfee, B. (1948). Carrot seed germination observations. Newsletter of the Association of Official Seed Analysts, 22, 17-18.
11. Elliot, G.A. (1929). Germination of carrot seed. Newsletter of the Association of Official Seed Analysts, 3, 12-15.
12. Everson, L. (1949). Preliminary studies to establish laboratory methods for the germination of weed seed. Proceedings of the Association of Official Seed Analysts, 39, 84-89.
13. Flemion, F. and Uhlmann, G. (1946). Further studies of embryoless seeds in the Umbelliferae. Contributions from the Boyce Thompson Institute, 14, 283-293.
14. Fornerod, C. (1975). Remarques sur la germination des semences potagères en laboratoire. Revue Horticulture Suisse, 48, 6-9.
15. Frank, W.J. and Wieringa, G. (1928). Artificial drying and low temperature as means employed in obtaining an increase in germination of some vegetable seeds. Proceedings of the Association of Official Seed Analysts, 19, 24-27.
16. Gardner, W.A. (1921). Effect of light on germination of light-sensitive seeds. Botanical Gazette, 71, 249-288.
17. Gray, D. (1979). The germination response to temperature of carrot seeds from different umbels and times of harvest of the seed crop. Seed Science and Technology, 7, 169-178.
18. Grime, J.P., Mason, G., Curtis, A.V., Rodman, J., Band, S.R., Mowforth, M.A.G., Neal, A.M. and Shaw, S. (1981). A comparative study of germination characteristics in a local flora. Journal of Ecology, 69, 1017-1059.
19. Guy, R. (1980). Quelques exemples des effets de la temperature sur la germination des plantes potagères. Revue Suisse de Viticulture, d'Arboriculture, et d'Horticulture, 12, 35-37.
20. Guy, R. (1981). Influence de la temperature sur la dureé de germination des semences de dix espèces potagères. Revue Suisse de Viticulture, d'Arboriculture et d'Horticulture, 13, 219-225.
21. Harrington, G.T. (1923). Use of alternating temperatures in the germination of seeds. Journal of Agricultural Research, 23, 295-332.
22. Hawthorn, L.R., Toole, E.H. and Toole, V.K. (1962). Yield and viability of carrot seeds as affected by position of umbel and time of harvest. Proceedings of the American Society for Horticultural Science, 80, 401-407.
23. Hegarty, T.W. (1973). Temperature sensitivity of germination in carrots: its frequency of occurrence and response to seed advancement. Journal of Horticultural Science, 48, 43-50.
24. Hegarty, T.W. (1975). Effects of fluctuating temperature on germination and emergence of seeds in different moisture environments. Journal of Experimental Botany, 26, 203-211.
25. Hendricks, S.B. and Taylorson, R.B. (1976). Variation in germination and amino acid leakage of seeds with temperature related to membrane phase change. Plant Physiology, 58, 7-11.
26. Hoefle, O.M. (1929). Results of a study of Daucus carota seeds. Proceedings of the Association of Official Seed Analysts, 21, 35-36.
27. Jacobsohn, R. and Globerson, D. (1981). Daucus carota (carrot) seed quality: I. Effects of seed size on germination, emergence and plant growth under sub-tropical conditions and II. The importance of the primary umbel in carrot seed production. In Seed Production (ed. P.D. Hebblethwaite), pp. 637-646, Butterworths, London.
28. Kotowski, F. (1926). Temperature relations to germination of vegetable seed. Proceedings of the American Society for Horticultural Science, 23, 176-186.
29. Kotowski, F. (1927). Temperature alternation and germination of vegetable seed. Acta Societatis Botanicorum Poloniae, 5, 71-78.
30. Kwon, O. (1970). Studies on the acceleration of germination in carrot seed. II. The effect of X-rays and ultraviolet light on the germination of carrot seed. Korean Journal of Botany, 13, 15-20. (From Horticultural Abstracts, 1973, 43, 691.)
31. Mann, L.K. and MacGillivray, J.H. (1949). Some factors affecting the size of carrot roots. Proceedings of the American Society for Horticultural Science, 54, 311-318.
32. Martin, J.N. (1943). Germination studies of the seeds of some common weeds. Proceedings of the Iowa Academy of Science, 50, 221-228.
33. Patterson, M.N. (1931). Germination studies of carrot seed. Proceedings of the Association of Official Seed Analysts, 23, 73-75.
34. Szafirowska, A., Khan, A.A. and Peck, N.H. (1981). Osmoconditioning of carrot seeds to improve seedling establishment and yield in cold soil. Agronomy Journal, 73, 845-848.
35. Wagenvoort, W.A., Boot, A. and Bierhuizen, J.F. (1981). Optimum temperature range for germination of vegetable seeds. Gartenbauwissenschaft, 46, 97-101.
36. Watanabe, S. (1955). [On germination of the Kintoki carrot seeds. II. Effects of pericarp removal, soaking and drying, and sun drying of seeds on their germination.] Journal of the Horticulture Association of Japan, 23, 237-244.
37. Watanabe, S. Asano, H. and Maeda, T. (1955). [On germination of the Kintoki carrot seeds. I. Delayed germination.] Kagawa Agriculture College, Technical Bulletin, 7, 27-30.
38. Wilkes, M. (1929). Germination of carrot seed. Newsletter of the Association of Official Seed Analysts, 3, 3-4.
39. Brocklehurst, P.A. and Dearman, J. (1983). Effects of calcium peroxide as a supplier of oxygen for seed germination and seedling emergence in carrot and onion. Seed Science and Technology, 11, 293-299.
FOENICULUM
|
F. capillaceum Gilib. |
|
|
F. vulgare Mill. [F. officinale All.; F.
Foeniculum Karst.; Anethum Foeniculum L.] |
fennel |
I. Evidence of dormancy
Freshly harvested seeds of fennel can show considerable dormancy (2,6,7) with, for example, no germination being reported at harvest, and only 41% germination after 3 months' after-ripening at room temperature (2), whilst as many as 18 months after-ripening at room temperature may be required to completely remove dormancy (7).
II. Germination regimes for non-dormant seeds
F. vulgare
TP; BP: 20°/30°C (16h/8h): 14d (ISTA)
BP: 20°/30°C (16h/8h): 14d (AOSA)
Alternating temperatures: 20°/30°C (16h/8h) (5,6)
III. Unsuccessful dormancy-breaking treatments
F. vulgare
Pre-chill: 5°C, 14-96d, germinate at 20°/10°C (day/night) (2)
IV. Partly-successful dormancy-breaking treatments
F. capillaceum
Constant temperatures: 6°-30°C in light or dark (9)
Alternating temperatures: 6°/16°C, 16°/25°C, light or dark (9); 6°/25°C in light (9)
F. vulgare
Constant temperatures: 15°C, 20°C (6); 8°-29°C (8)
Alternating temperatures: 20°/30°C (16h/8h) (6,7); 20°/10°C (day/night) (2); 15°/22°C, 22°/29°C (16h/8h) (8)
Pre-dry: room temperature, 3d (6)
Light: dark (7)
V. Successful dormancy-breaking treatments
F. capillaceum
Alternating temperatures: 6°/25°C in dark (9)
F. vulgare
Alternating temperatures: 20°/30°C (16h/8h), 14d, then dry ungerminated seeds, room temperature, 3d, then return to 20°/30°C (16h/8h) (6,7)
Pre-chill: 10°C, 5d, germinate at 20°/30°C (16h/8h) (5)
Warm stratification: 20°C, 14d, then germinate at 20°/30°C (16h/8h) (6)
Pre-wash: 24h, germinate at 18°C in dark (1)
VI. Comment
Dormancy will not be the only problem encountered when attempting to germinate fennel seeds. As with other members of the Umbelliferae the variation in maturity within a plant means that certain "seeds" may lack embryos, whilst others may be immature with only partly-developed embryos. Consequently at the end of germination tests the seeds which have failed to germinate should be cut to determine whether or not they possess an embryo: as many as one third of "seeds" may lack embryos (3,4).
Within the range 8°-29°C, a constant temperature of 15°C is the most suitable for germination tests (8). (Incidentally, previous ISTA rules, 1976, recommended a constant temperature germination test regime of 15°C as a dormancy-breaking procedure.) Alternating temperature regimes of 15°/22°C or 22°/29°C (16h/8h) provided no additional stimulation of germination beyond that at a constant 15°C (8). However, in another investigation an alternating temperature regime of 20°/30°C (16h/8h) resulted in much greater germination than constant temperatures of either 15°C or 20°C (6). Germination in the dark is reported to be consistently superior to that in the light (7,9).
The following regime is suggested for fennel seed germination tests: a 5-day pre-chill at 10°C, then transfer to an alternating temperature regime of 20°/30°C (16h/8h) in the dark. If this proves inadequate for the more dormant accessions then impose a pre-wash treatment prior to pre-chilling.
VII. References
1. Chaturvedi, S.N. and Muralia, R.N. (1975). Germination inhibitors in some umbellifer seeds. Annals of Botany, 39, 1125-1129.
2. Doust, J.L. and Doust, L.L. (1982). Life-history patterns in British Umbelliferae: a review. Botanical Journal of the Linnean Society, 85, 179-194.
3. Flemion, F. and Hendrickson, E.T. (1949). Further studies on the occurrence of embryoless seeds and immature embryo in the Umbelliferae. Contributions from the Boyce Thompson Institute, 15, 291-297.
4. Flemion, F. and Uhlmann, G. (1946). Further studies of embryoless seeds in the Umbelliferae. Contributions from the Boyce Thompson Institute, 14, 283-293.
5. Fornerod, C. (1975). Remarques sur la germination des semences potagères en laboratoire. Revue Horticole Suisse, 48, 6-9.
6. Guy, R. (1979). Observations sur la dormance et la germination des semences de fenouil. Revue Suisse d'Agriculture, 11, 131-133.
7. Guy, R. (1979). Nouvelle observations sur la maturité, la dormance, la germination et la levée des semences de fenouil. Revue Suisse de Viticulture, d'Arboriculture et d'Horticulture, 11, 215-217.
8. Guy, R. (1981). Influence de la temperature sur la durée de germination des semences de dix espèces potagères. Revue Suisse de Viticulture, d'Arboriculture et d'Horticulture, 13, 219-225.
9. Styk, B. (1970). [The effect of different temperatures and light on the germination of fennel, Foeniculum capillaceum.] Annales Universitatis Mariae Curie-Sklodowska, E, 1969, 24, 277-288. (From Horticultural Abstracts, 1972, 42, 1957.)
PASTINACA
|
P. sativa L. |
parsnip |
I. Evidence of dormancy
Freshly harvested seeds of cultivated and, particularly, wild parsnips may show considerable dormancy (1,2,4,9,11). For example, despite 3 months after-ripening at room temperature, wild parsnip seeds did not germinate (2), and buried seeds in soil required 5 months overwintering (i.e. pre-chilling) before germination would occur (11). Successful after-ripening periods reported by others range between 1 month (10) and 2 years (9). As with other umbellifers, considerable problems in interpreting results of germination tests are caused by the presence of seeds without embryos or with only immature embryos. These may represent, for example, 8% and 44% respectively of seed-like structures within an accession (5,6).
II. Germination regimes for non-dormant seeds
BP; TP: 20°/30°C (16h/8h): 28d (ISTA)
BP; S: 20°/30°C (16h/8h): 28d (AOSA)
III. Unsuccessful dormancy-breaking treatments
Constant temperatures: 10°C, 15°C, 20°C (2); 15°-30°C (8)
Alternating temperatures: 10°/20°C (night/day) (2); 25°/30°C, 30°/35°C (16.5h/7.5h) (8); 15°/6°C, 35°/20°C (12h/12h) in dark (1)
Pre-chill: 5°C, 12w, germinate at 30°/15°C, 35°/20°C (12h/12h) in light or dark (1); 1°C, 2-10d, germinate at 20°C (4)
Pre-dry: 103°C, 2h (9); 95°C, 4h (9); imbibe/dry (24h/48h), 1-8 cycles (7); imbibe/dry (8h/24h), 6 cycles (7); imbibe/dry (48h/48h), 1-4 cycles (7)
Polyethylene glycol: pre-applied, 5-20d, -10, -15 bar (7)
Potassium nitrate: pre-applied, plus tripotassium orthophosphate, pre-applied, 5-20d, -10, -15 bar (7)
IV. Partly-successful dormancy-breaking treatments
Alternating temperatures: 30°/15°C, 35°/20°C, 20°/10°C (12h/12h) in light, 2100 lux, 14h/d (1); 15°/20°C, 15°/25°C, 20°/25°C, 15°/30°C, 20°/30°C, 15°/35°C, 20°/35°C (16.5h/7.5h) (8); 15°/25°C (16h/8h) (9)
Pre-chill: 5°C, 12w, germinate at 15°/6°C, 20°/10°C (12h/12h) (1); 5°C, 14-74d (2)
Warm stratification: 20°C, 1-6d, then pre-chill, 1°C, 2d (4)
Polyethylene glycol: pre-applied, 10d, -10 bar, 20°C (4)
Pre-dry: 60°C, 4d (9)
V. Successful dormancy-breaking treatments
Constant temperatures: 15°C (9)
Alternating temperatures: 20°/30°C (16h/8h) (9); 20°/30°C (16h/8h) in light (3); 15°/20°C (16h/8h) (9)
Pre-chill: 5°C, 3m (2)
Warm stratification: 20°C, 1-6d, then pre-chill, 1°C, 6-10d (4); 20°C, 3d, then pre-chill, 1°C, 8-12d (4)
VI. Comment
Dormant parsnip seeds require long pre-chill treatments (1,2,4,11), alternating temperatures (1,3,8,9) and light (1,3) for germination. It is suggested that the AOSA/ISTA prescriptions for the germination test regime be followed (see above), but with light applied (3,9) plus, where dormancy is encountered, substantial - up to 12 weeks for wild parsnip - pre-chill treatments at 3°-5°C.
VII. References
1. Baskin, J.M. and Baskin, C.M. (1979). Studies on the autecology and population biology of the weedy monocarpic perennial Pastinaca sativa. Journal of Ecology, 67, 601-610.
2. Doust, J.L. and Doust, L.L. (1982). Life-history patterns in British Umbelliferae: a review. Botanical Journal of the Linnean Society, 85, 179-194.
3. Everson, L. (1949). Preliminary studies to establish laboratory methods for the germination of weed seed. Proceedings of the Association of Official Seed Analysts, 39, 84-89.
4. Finch-Savage, W.E. and Cox, C.J. (1982). A cold-treatment technique to improve the germination of vegetable seeds prior to fluid drilling. Scientia Horticulturae, 16, 301-311.
5. Flemion, F. and Henrickson, E.T. (1949). Further studies on the occurrence of embryoless seeds and immature embryos in the Umbelliferae. Contributions from the Boyce Thompson Institute, 15, 291-297.
6. Flemion, F. and Uhlmann, G. (1946). Further studies of embryoless seeds in the Umbelliferae. Contributions from the Boyce Thompson Institute, 14, 283-293.
7. Gray, D. and Steckel, J.R.A. (1977). Effects of pre-sowing treatments of seeds on the germination and establishment of parsnips. Journal of Horticultural Science, 52, 525-534.
8. Harrington, G.T. (1923). Use of alternating temperatures in the germination of seeds. Journal of Agriculture Research, 23, 295-332
9. Joseph, H.C. (1929). Germination and keeping quality of parsnip seeds under various conditions. Botanical Gazette, 87, 195-210.
10. Myers, A. (1935). The viability of parsnip seed. Agricultural Gazette of New South Wales, 46, 672.
11. Roberts, H.A. (1979). Periodicity of seedling emergence and seed survival in some Umbelliferae. Journal of Applied Ecology, 16, 195-201.
PETROSELINUM
|
P. crispum Nym. [P. sativum Hoffm.; P.
hortense Hoffm.; Apium petroselinum L.; Apium crispum
Mill.] |
parsley |
I. Evidence of dormancy
Seed dormancy in both cultivated and wild parsley accessions is reported to be only slight (2). Nevertheless the germination of seeds of the cultivated parsley is slow and the total proportion of seeds which eventually germinate low (3). This is mainly due to high proportions of immature - up to 35-50% (4) - and empty - up to 36% (5) - seeds.
II. Germination regimes for non-dormant seeds
BP; TP: 20°/30°C (16h/8h): 28d (ISTA)
BP; S: 20°/30°C (16h/8h): 28d (AOSA)
Alternating temperatures: 30°/20°C (16h/8h) (5)
III. Unsuccessful dormancy-breaking treatments
Constant temperatures: 20°C in light (3)
Pre-chill: 5°C, 40-96d (2)
IV. Partly-successful dormancy-breaking treatments
Constant temperatures: 10°C, 15°C, 20°C (2)
Pre-wash: 24h, germinate at 15°C in dark (3)
Polyethylene glycol: pre-applied, 2,3w, -9, -12 bar, germinate at 15°C in dark (3)
V. Successful dormancy-breaking treatments
Constant temperatures: 3°-17°C (1); 0°-20°C (7); 5°-25°C (3)
Alternating temperatures: 30°/20°C (16h/8h) (5); 10°/20°C (night/day) (2)
Pre-chill: 5°C, 2w (2)
Pre-wash: 24h, then polyethylene glycol, pre-applied, 2,3w, -9, -12 bar, germinate at 15°C in light or dark (3)
VI. Comment
Full germination occurs over a wide range of constant (1,3,7) and alternating temperature regimes (5). Within the constant temperature range 15°-25°C and alternating temperatures between a minimum of 15°C and a maximum of 30°C there is reported to be no advantage to any one regime (6). However, results from comparisons of the germination of more dormant seeds in constant and alternating temperature regimes show a very great advantage from testing at alternating temperatures (2). Consequently it is suggested that the seeds be tested for germination under alternating temperature regimes; preferably 10°/20°C (2), but the regime 20°/30°C prescribed by ISTA/AOSA may be adequate.
VII. References
1. Bierhuizen, J.F. and Wagenvoort, W.A. (1974). Some aspects of seed germination in vegetables. I. The determination and application of heat sums and minimum temperature for germination. Scientia Horticulturae, 2, 213-219.
2. Doust, J.L. and Doust, L.L. (1982). Life-history patterns in British Umbelliferae: a review. Botanical Journal of the Linnean Society, 85, 179-194.
3. Ely, P.R. and Heydecker, W. (1981). Fast germination of parsley seeds. Scientia Horticulturae, 15, 127-136.
4. Flemion, F. and Henrickson, E.T. (1949). Further studies on the occurrence of embryoless seeds and immature embryos in the Umbelliferae. Contributions from the Boyce Thompson Institute, 15, 291-297.
5. Flemion, F. and Uhlmann, G. (1946). Further studies of embryoless seeds in the Umbelliferae. Contributions from the Boyce Thompson Institute, 14, 283-293.
6. Harrington, G.T. (1923). Use of alternating temperatures in the germination of seeds. Journal of Agricultural Research, 23, 295-332.
7. Thompson, P.A. and Fox, D.J.C. (1976). The germination responses of vegetable seeds in relation to their history of cultivation by man. Scientia Horticulturae, 4, 1-14.
