Ecological Significance of Seed Coat Impermeability to Moisture in Crimson, Subterreanean and Rose Clovers in a Mediterranean‐Type Climate

Williams, William A.; Elliott, John R.

doi:10.2307/1931807

Cited by 52 publications

(22 citation statements)

References 12 publications

(15 reference statements)

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“…Impermeability occurs in the yellow seeds, which are more dehydrated in maturation. This fact reinforces the hypothesis about the influence of the degree of dehydration in the acquisition of impermeability on the so-called "hard seeds" [19] [20], but contradicts that of impermeability as a consequence of phenol oxidation in the seed coat during dehydration, as suggested by several authors [21] [22] [23]. The developmental series originating dormant yellow seeds and quiescent brown ones in the same fruit cannot be a case of heterocrony as defined by Silvertown [7], actually representing distinct metabolic pathways.…”

Section: Discussionsupporting

confidence: 88%

“…The chemical and anatomic changes that alter the seed coat permeability are not completely understood but it is considered that impermeability is due to the final thickening, by the suberization or lignifications of columnar cell walls in seed coats [17] [18]. Impermeability is acquired in the final maturation stages being particularly influenced by the relative air humidity during the dehydration of orthodox seeds [19] [20], whereas low humidity favors impermeable coats [7].…”

Section: Introductionmentioning

confidence: 99%

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Somatic Polymorphism Variation in <i>Crotalaria retusa</i> L. Seeds

Figueiredo¹,

Silva²

2018

AJPS

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The article describes the somatic polymorphism in Crotalaria retusa L. seeds.Each individual may produce yellow dormant seeds, brown quiescent seeds and unviable dark brown ones. Therefore, regarding physiology it is a dimorphism. We show that autogamy reduces dimorphism, favoring the formation of dormant seeds. However, the significant variation in dimorphism is seasonal as consequence of increased viability of dormant seeds under drier weather conditions. The variation is a phenotypic response to changes of humidity in the environment during plant reproduction, a mechanism inducing the prevalence of dormant seeds in the dry season and quiescent seeds during the rainy season. The seasonal alternation between dormancy and quiescence in seasonally dry environments has an apparent adaptive value. The chromatic polymorphism increases on the more humid coast and during the rainy season, due to increased mortality of dormant seeds under wetter weather conditions. Unviable seeds accumulate oxidized phenols in their seed coat that possibly act as induced chemical defenses. Its proportion increases with humidity, accentuating polymorphism, also in response to the increase in the predation rate by larvae of U. ornatrix during the rainy season.

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Section: Discussionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Somatic Polymorphism Variation in <i>Crotalaria retusa</i> L. Seeds

Figueiredo¹,

Silva²

2018

AJPS

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“…Although a high proportion of hard seed may be an adaptive strategy for survival under unfavorable growing conditions and for prolonged maintenance of viability (Williams and Elliott 1960), it inhibits or delays germination and therefore is undesirable for commercial seed. In seed stored for 420 d, there was significant variation among 10 polycross progenies for hard seed content (Miklas et al 1987).…”

Section: Improvement In Seed Germinationmentioning

confidence: 99%

A review of research progress on cicer milkvetch (Astragalus cicer L.)

Acharya¹,

Kastelic²,

Beauchemin³

et al. 2006

Can. J. Plant Sci.

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. 2006. A review of research progress on cicer milkvetch (Astragalus cicer L.). Can. J. Plant Sci. 86: 49-62. This review of cicer milkvetch includes both published and unpublished information regarding crop and seed characteristics, seed treatments, breeding, agronomic practices and nutritional value for livestock. Cicer milkvetch is a long-lived perennial, acid-and drought-tolerant crop providing high-quality forage throughout the growing season. It does not cause bloat in ruminants. Although it has caused photosensitization in ruminants, this was apparently due to specific environmental conditions and the cultivar used. Cicer milkvetch is compatible with other forage crops in mixed stands and is particularly suitable for pasture. Although the crop has many good qualities and was introduced in North America approximately 75 yr ago, it has not been utilized extensively, primarily due to slow establishment. However, stand establishment has been improved by elucidation of seed and seedling characteristics, followed by selection for heavy seed, rate of emergence, and mature plant vigor. Improved cultivars, developed through recurrent selection for rapid establishment, are now available. Seed scarification, inoculation with rhizobia, and shallow seeding into a pre-packed, warm seedbed are of great importance in cicer milkvetch establishment. Seeding later in the spring (without a companion crop) increases the probability of successful establishment of genetically improved cultivars. Development of cultivars with upright growth characteristics and long-term persistence under grazing stress, improved scarification techniques (to reduce seed loss), and a seeding protocol for successful establishment of the crop, have the potential to substantially increase utilization of this important forage legume. Cette revue bibliographique englobe l'information connue et inédite sur les caractéristiques de la plante et de la graine, les traitements grainiers, l'hybridation, les pratiques agronomiques et la valeur nutritive de cette culture pour le bétail. L'astragale est une vivace longévive qui tolère bien les sols acides et la sécheresse; elle produit un fourrage de haute qualité pendant toute la période végétative. Elle n'entraîne pas le météorisme chez les ruminants. La photosensibilisation qu'elle engendre à l'occasion chez eux semble résulter de certaines conditions environnementales ainsi que du cultivar employé. L'astragale est compatible avec d'autres plantes fourragères dans les peuplements mixtes et se prête particulièrement bien aux pâturages. En dépit de ses nombreuses qualités et de son introduction en Amérique du Nord il y a près de 75 ans, l'astragale n'est pas énormément utilisée, principalement parce qu'elle prend du temps à s'implanter. On peut néan-moins améliorer l'établissement de la culture en triant les semences et les plantules d'après leurs propriétés puis en sélectionnant les plants pour une production abondante de graines, le taux de levée et la vigueur des plants adultes. On trouve désormais sur le ma...

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“…The biological and ecological significance of seed coat impermeability has been discussed by various authors (Williams and Elliott 1960 1973 ;Rolston 1978 ;Bewley and Black 1982 ;Fenner 1985 ;Baskin and Baskin 1989) and methods to overcome it have been reviewed by Robertson (1948/49), Cavanagh (1980, Willan (1985) and Cavanagh (1987). Seed coat impermeability is a valuable characteristic for the survival of a species under conditions of climatic adversity .…”

Section: Resultsmentioning

confidence: 99%

The effect of different pre-sowing seed treatments, temperature and light on the germination of five Senna species from Ethiopia

Teketay

1996

New Forest

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Application. For maximum, uniform and rapid germination of Senna species with hard seed coat imposed dormancy, use pre-sowing treatments involving mechanical scarification, acid or boiling water treatments . Once dormancy is broken, seeds can be sown in nurseries with the temperatures ranging between 15-30°C .Abstract. The germination requirements of five Senna species : S. bicapsularis, S. didymobotrya, S. multiglandulosa, S. occidentalis and S. septemtrionalis have been investigated . Seeds possess dormancy which is caused by their hard seed coats hampering maximum, uniform and rapid germination . To overcome this dormancy, seeds of the five species were pre-treated with (a) mechanical scarification, (b) concentrated sulphuric acid for 15, 30, 45 and 60 minutes and (c) boiling water for 15, 30, 45 and 60 seconds . To determine the effects of temperature on the germination of seeds, pre-treated seeds from each species were incubated at 10, 15, 20, 25 and 30°C . Germination was also tested in the dark . Both acid treatment and mechanical scarification resulted in fast and uniform germination . The highest germination (95-100%) for all species was obtained from seeds treated with sulphuric acid for 60 minutes . Mechanical scarification resulted in 100% germination in all the species except S . septemtrionalis (59%) . Boiling water improved germination significantly in S. didymobotrya (98%), S. occidentalis (82%) and S. septemtrionalis (97%), but had very little effect on S. multiglandulosa and reduced germination in S . bicapsularis. Senna seeds germinated over a wide range of temperatures with the optimum temperatures for germination falling around 20-25°C . Germination was either completely inhibited or very low at 10°C . Seeds of all species germinated both in light and dark conditions .

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Ecological Significance of Seed Coat Impermeability to Moisture in Crimson, Subterreanean and Rose Clovers in a Mediterranean‐Type Climate

Cited by 52 publications

References 12 publications

Somatic Polymorphism Variation in <i>Crotalaria retusa</i> L. Seeds

Somatic Polymorphism Variation in <i>Crotalaria retusa</i> L. Seeds

A review of research progress on cicer milkvetch (Astragalus cicer L.)

The effect of different pre-sowing seed treatments, temperature and light on the germination of five Senna species from Ethiopia

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Ecological Significance of Seed Coat Impermeability to Moisture in Crimson, Subterreanean and Rose Clovers in a Mediterranean‐Type Climate

Cited by 52 publications

References 12 publications

Somatic Polymorphism Variation in &lt;i&gt;Crotalaria retusa&lt;/i&gt; L. Seeds

Somatic Polymorphism Variation in &lt;i&gt;Crotalaria retusa&lt;/i&gt; L. Seeds

A review of research progress on cicer milkvetch (Astragalus cicer L.)

The effect of different pre-sowing seed treatments, temperature and light on the germination of five Senna species from Ethiopia

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Product

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Somatic Polymorphism Variation in <i>Crotalaria retusa</i> L. Seeds

Somatic Polymorphism Variation in <i>Crotalaria retusa</i> L. Seeds