红树植物白骨壤叶片凋落物浸提液对桐花树胚轴萌发与幼苗生长的化感作用

Avicennia marina and Aegiceras corniculatum are two indigenous and common mangrove species dominantly distrib-uting in intertidal mangrove of southern China. In this research, the allelopathic effects of different concentrations of leaf litter leachates (0, 2, 10, 20, and 50 g•L^-1) from A. marina on the hypocotyl germination and seedling growth of A. corniculatum were studied. The results were as followed: with the increase concentrations of A. marina leaf litter leachate treatments, the numbers of fine and nutritive roots and stem longth in A. corniculatum de-creased gradually and the germination time of roots and stems became longer steadily. However, another trend was found that hypocotyl germination rate and seedling leaf biomass and root-shoot ratio enhanced significantly under 2 g•L^-1 concentration of A. marina leaf litter leachate treatment but decreased when the concentrations increased to 10, 20, and 50 g•L^-1. The hypocotyl rooting rate, fine/nutritive root lengths, leaf number, and root/stem biomasses of A. corniculatum decreased gradually under 50 g•L^-1 concentration of A. marina leaf litter leachate treatment, while there were no obvious allelopathic effects on the above physiological prop-erties of A. corniculatum subjected to 2, 10, and 20 g•L^-1 concentrations of A. marina leaf litter leachate treatments. For A. corniculatum, the seedling growth elicited a more sensitive allelopathic response to leaf litter leachates from A. marina compared to its hypocotyl germination.