The Research On The Dormancy Mechanism And Its Relieving Techniques Of Tilia Amurensis Seeds

Tilia amurensis was a second-class protected wild plant and had pharmaceutical value,timber value and ornamental value,but deep dormancy characteristic restricted its reproduction. The research on its dormancy was not further to date. This paper systematically studied the permeability of the testa and change law of endogenous hormones of Amur linden seeds during cold stratification and the kinds and content of the inhibition of germination and methods of dormancy relieving, providing the scientific basis for the breeding of Amur linden.The testa of Amur linden had poor permeability for the waterproof compact layer. There was germiation inhibitors in the pericarp, testa and endosperm(embryo) and the inhibitory activities was ordered as testa>pericarp>endosperm(embryo),which had a positie correlation with the concentration.The inhibitory activities for the percentage germination of B.pekinensis seedlings of all organic phases and water phase in the embryo ordered as followed:ethyl acetate phase> petroleum ether phase> ethylether phase>water phase> methanol phase,while the order for the root growth of B.pekinensis seedlings was petroleum ether phase> water phase>ethyl acetate phase> ethylether phase> methanol phase. For the testa, the inhibitory activity orders were methanol phase> water phase>ethyl acetate phase> ethylether phase> petroleum ether phase and methanol phase>water phase>ethylether phase>ethyl acetate phase> petroleum ether phase respectively. For the pericarp, the inhibitory activity orders were ethyl acetate phase>methanol phase>petroleum ether phase>water phase>ethylether phase and methanol phase>ethyl acetate phase>petroleum ether phase>ethylether phase>water phase respectively.Following the process of cold stratifaction, the content IAA gradually increased, while ABA decreased; the content of ZT first increased and then decreased followed by an upward trend. Whenas, IAA/ABA ratio increased and then decreased, ZT/ABA ratio increased first and then decreased and later increased once again.The compounds identified by GC-MS was mainly organic acid, unsaturated ester, alcohol, ketone, phenol, which had a greater content included dichloroacetic acid, malonic acid, thiocyanate, azelaic acid, phthalic acid, succinic acid, adipic acid, valeric,17-18acetylenic acid, fluorobenzoic acid, bitter, ten five alkyl acid.The method quickly accelerated germination wasrshaked off pericarp by mechanical way, then applied100℃water for2s and100mg·L-1concentration of GA3and6-BA and stratification (15-20℃/10d�'0-5℃/15d) resulted in higher germination rate in Amur linden dormant seeds less than1month, which was70.2%.