黄连须根浸提液对莴苣、绿豆和白菜的化感效应

试验以莴苣、绿豆和白菜为材料,研究了黄连须根浸提液(extracts from fibrous roots of Coptis chinensis, ERC)对种子萌发和幼苗生长的化感效应,目的是减轻化感危害,提高土地持续生产力。结果表明,低浓度(200 mg/L)的ERC处理种子后,3种供试作物种子发芽率、发芽指数无显著变化,但种子的活力指数降低,幼苗的生物量和根系活力显著下降;随着浓度加大(>400 mg/L),抑制种子中的淀粉和蛋白质水解,降低游离氨基酸、可溶性糖和可溶性磷的含量,影响种子萌发;ERC浓度达到800 mg/L时,根尖向上卷曲而离开ERC溶液,根毛消失,根系畸形且颜色变褐,叶片硝酸还原酶和叶绿素合成减少,抑制幼苗生长。ERC对莴苣种子发芽和幼苗生长抑制作用大于绿豆和白菜。因此,在集约化种植黄连的土壤中,可能造成莴苣、绿豆和白菜等后季作物减产。

Allelopathic effect of extracts from the fibrous roots of Coptis chinensis on Lactuca compositae,Vigna radiate and Brassica rapa pekinensis

A study has been undertaken of the allelopathic effect of extracts from fibrous roots of Coptis chinen-sis (ERC)on seed germination and seedling growth in Lactuca compositae ,Vigna radiate and Brassica rapa pekinensis.Seeds of the three species were cultured in plates with various concentrations of ERC and germina-tion rate,young seedling growth and related physiological indexes were measured.There was no significant effect of ERC on seed germination rate and index at low concentrations (200 mg/L),but seed vitality decreased and seedling biomass and root vitality dropped greatly.As the concentration of ERC increased to>400 mg/L, seed starch and protein hydrolyses were inhibited and the contents of free amino acids,soluble sugars and solu-ble phosphorus decreased,resulting in poor germination.When ERC concentration reached 800 mg/L,roots deformed concomitantly with brown color,root hair disappearance and the curling-up of root tips to leave the ERC solution.Nitrate reductase activity and chlorophyll concentration also decreased in the leaves.As a result, seedling growth was stunted.Stronger inhibition of ERC on L.compositae was observed than on V .radiate and B .rapa pekinensis .The results thus show that allelopathic chemicals contained in root exudate and residu-al of C.chinensis could inhibit seed germination and seedling growth in these three plants.This inhibitioncould result in poor growth and yield reduction of consequent crops after intensive cultivation of C.chinensis .