Seed Germination

1359 Words6 Pages

Seed is a fertilized matured ovule consisting of an intact embryo, endosperm and or cotyledon with protective covering (seed coat). The eventual function of the surviving seed is its germination. A dormant seed is one that does not have an ability to grow in a predefined time frame under any combination of normal physical environmental factors, that are generally is favourable for its germination. A viable seed goes from a dormant, quiescent state to one of active growth, allowing the embryo to break through its seed coat in the process of germination. (Baskin and Baskin, 2004)
For germination to occur, a seed requires moisture, suitable temperature and in most cases an aerobic atmosphere. If one or more of these requirements are not met, germination …show more content…

Dormancy in Iris seeds is because of water and ether-dissolvable germination inhibitors in the endosperm that can be drained from the seeds with water or avoided by embryo excision (Arditti and Pray 1969). Inhibitors have been found in the seeds of such vegetable and flower families as Polygonaceae, Brassicaceae, Chenopodiaceae, Linaceae (Linum), Lamiaceae (Lavendula), Portulaceae (Portulaca), and Violaceae (Atwater, 1980).
In different species, for example, cucumber (Cucumis) and spinach (Spinacia), adhesive layers on the seed coverings can restrict gaseous exchange (Bewley and Black, 1982). These layers of integument and leftovers of the endosperm and nucellus remain physiologically active during ripening and after the seed are isolated from the plant. Such physiologically active layers maintain primary dormancy, mainly because semipermeable nature limits air circulation and inhibitor development.

Fleshy fruits, or juices from them, can firmly repress seed germination as in Cucumis, and Lycopersicon species. Moreover, chemicals extracted from dry products of the soil covers, for example, those in Beta, can restrain germination. Some of the substances connected with dormancy are various phenols, coumarin, and abscisic acid (Bewley and Black,

More about Seed Germination

Open Document