Poster: Seed biology

Abs # 720: Microarray analysis of gene expression in Brassica napus seed dormancy

Presenter:	Fei, Houman , houman.fei@nrc-cnrc.gc.ca
Authors	Fei, Houman  (A)   Tsang, Edward  (A)   Cutler, Adrian  (A)
Affiliations:	(A): Plant Biotechnology Institute

Seed dormancy is defined as a state in which viable seeds do not germinate even under environmental conditions normally favorable for germination. It is an adaptation that allows a species to determine the timing of germination for seeds in a population. Seed dormancy may be categorized into primary dormancy, which is induced during the late stage of seed development by endogenous factors sourcing from embryo, endosperm and maternal tissues such as testa or pericarp, and secondary dormancy, which is imposed in certain seeds by abiotic stresses, e.g., light, moisture, anoxia and temperature. Although seed dormancy occurs widely, in some crop species seeds have little or no primary dormancy. These seeds may germinate on the maternal plants before harvest, i.e., “viviparity”. In some species, seeds have no primary dormancy, but secondary dormancy can be induced by environmental factors, which may lead “volunteer” seeds to persist in the soil seedbank for years. Thus, control of seed dormancy is of practical importance. Many studies have been conducted on primary seed dormancy. However, less is known about secondary dormancy including how radicle emergence is blocked, which metabolic and signaling processes occur in the dormant state and the mechanism by which dormancy is released. Previous work showed that dormancy in seeds of Brassica napus cv. DH12075 is not inducible, however, in cv. AC Excel seeds, induction of secondary dormancy may reach 50-80% by PEG treatment, and the PEG-induced dormancy can be broken by low temperature treatment. In the present work, we are using the microarray technique to study gene expression in B. napus seed dormancy. We will report preliminary results of our experiments.