双子叶植物中的光敏种子及其生物学特征

LIGHT SENSITIVE SEEDS IN DICOTYLEDONS AND THEIR BIOLOGICAL CHARACTERS

This paper reported the light sensitive seeds (LS seed) in 43 families, 84 genera. The morphological charaters of LS seeds, seed dispersal type, plant growth behavious and distribution in dicotyledon plant system are discussed. LS seed is very small. 44.7% of LS seeds is B type of seed morphology and 20% is C type, usually LS seed has a semi-permible membrane inner seedcoat. Endosperm doesn't correlate with LS dormancy, 58.8% of LS seeds has endosperm and 41.2% hasn't. Anemochore, hydrochore and epizoochore is main types of seed dispersal in light sensitive seeds. Thereare a lot of LS seeds in herbaceous plants. In Takhtajan dicotyledon system LS seeds mainly distribute in Caryophyllidae, Asteridae and Lamidae, 37%, 23% and 26% of families own LS seeds respectively in these subclasses, only 4.8% of families in Magnoliidae have LS seeds. According the distribution of LS seeds in plant system and the ecological affects, we suges ted that light sensitive dormancy was a more developed seed dormant type. LS dormancyperfected the function of mass small seeds and dispersal, so it increased the competitive ability of plant.