假臭草浸提液对玉米根系活力的影响

Allelopathic Study on Aqueous Extract of Praxelis clematidea on Root Activity in Maize

对不同假臭草浸提液处理的玉米幼苗根系活力进行测定,并通过生物活性作用响应指数RI(response index)研究假臭草浸提液的化感作用强度。结果表明,在假臭草浸提液浓度分别为0.0125g(FW)/mL(A1)、0.025g(FW)/mL(A2)、0.05g(FW)/mL(A3)时,对玉米根系影响的RI平均值分别为-0.1675、-0.3033、-0.4706,假臭草浸提液浓度越大,RI值随之越大;假臭草新鲜茎叶(B1)、新鲜根系(B2)、烘干茎叶(B3)及烘干根系(B4)组织浸提液对玉米根系影响RI平均值分别为-0.5251、-0.2651、-0.2379、-0.2272;不同浓度及不同组织浸提液交互作用间,在0.05g(FW)/mL(A3)浓度下,假臭草新鲜茎叶组织对玉米根系影响的RI平均绝对值最大(RI=-0.8949),在0.0125g(FW)/mL(A1)浓度下,假臭草新鲜茎叶组织对玉米根系影响的RI平均绝对值最小(RI=-0.1252)。假臭草浸提液具有一定的化感作用,浓度越高,其化感作用越强,茎叶组织浸提液的化感作用比根系浸提液的强,新鲜假臭草组织的化感作用比烘干组织的强。

Praxelis clematidea, regarded as a kind of malignant weed in recent years, possesses strong absorbing capacity of soil nutrition and intense allelopathy, releasing allelochemicals to inhibit the growth of other plants.This paper assayed the root activities of maize seedling treated by different P.clematidea extracts, and studied the allelopathic intensity of P.clematidea extracts by RI （response index）, biological activity effect.The results showed that the values of RI were-0.167 5,-0.303 3,-0.470 6, when the maize seedling roots were treated with the aqueous extracts from P.clematidea at concentrations of 0.012 5 g（FW）/ ml（A1）, 0.025 g（FW）/ml（A2）, 0.05 g（FW）/ml（A3）, respectively.The higher the concentration was, the bigger the RI was.The values of RI were-0.525 1,-0.265 1,-0.237 9,-0.227 2 when maize roots were treated with extracts from fresh stems and leaves（B1）, fresh roots（B2）, dry stems and leaves（B3）, dry roots（B4）, respectively.In the result of interactions between different concentrations or tissue extracts, the peak of absolute value of RI （-0.894 9） appeared when maize roots were treated with extracts from fresh stems and leaves at the concentration of 0.05 g（FW）/ml（A3） , and the absolute value of minimum RI（-0.125 2） was appeared when maize roots were treated with extracts from fresh stems and leave at the concentration of 0.012 5 g （FW）/ml（A1）.The P.clematidea extracts had certain allelopathy.The higher the concentration was, the stronger the allelopathy presented.The P.clematidea extract had stronger allelopathy in stem and leaf than that in root and the allelopathy in fresh P.clematidea tissue is stronger than that in drying tissues.