Effect of cold stratification, scarification and hormones on germination of dimorphic seeds of Atriplex centralasiatica under saline conditions.

摘要

The effect of cold stratification, seed coat scarification and plant hormones on germination of black and brown seeds of Atriplex centralasiatica under saline conditions was investigated. Cold stratification increased the germination rate, but did not affect final germination percentage of either brown or black seeds. Seed coat scarification and fluridone (Abscisic acid [ABA] biosynthesis inhibitor) improved germination of both types of seeds under salinity stress. In both brown and black seeds, gibberellin, 1-aminocy-cloproane-1-carboxylate (the immediate precursor of ethylene) and 6-benzyladenine, had little effect on the germination under salinity. Paclobutrazol (inhibitor of gibberellin biosynthesis) and ABA did not affect germination in distilled water, whereas ABA inhibited germination in saline conditions for both types of seeds. Paclobutrazol inhibited the germination of black seed only under salinity. Black seeds were more sensitive to ABA than brown seeds in salinity stress. Brown seeds contained more active gibberellins than black seeds, although they contained a similar level of ABA. In conclusion, the production of black and brown seeds showed bet-hedging ecological strategies. Gibberellins in seeds and ABA in seeds and bracteoles were the main plant hormones that affected the germination of dimorphic seeds.