桔梗水浸提液对小麦幼苗的化感作用

采用培养皿滤纸法研究了不同浓度桔梗水浸提液对小麦的幼苗生长及生理生化指标的影响，探讨桔梗植株水浸提液对小麦的化感作用，推测其可能的生理机制。结果表明：桔梗植株水浸提液对小麦幼苗的地上部生长表现为低浓度（≤1mg／mL）促进、高浓度（5—20mg／mL）抑制作用；对根部生长为抑制作用，且抑制强度大于地上部。随处理浓度的升高，小麦幼苗体内POD活性、脯氨酸含量、MDA含量逐渐升高；CAT活性、根系活力、光合色素含量先升高后降低；可溶性蛋白含量和伤害率先降低后升高。桔梗植株水浸提液对小麦总体的化感效应表现为低促高抑，小麦可作为桔梗的轮作作物种植。

Allelopathy of aquatic extracts on wheat from Platycodon grandiflorum seedlings

In this paper, petridish bionssays were conduested to investigate the effects of different concentrations of aquatic extracts from P. grandiflorum on the growth and related physiological and biochemical indexes of wheat seedlings. The allelopathy of the aquatic extracts on wheat seedlings was studied, and the corresponding physiological mechanism was presumed. Results showed that the growth of the aerial parts of wheat seedlings was promoted by low concentration of acquatic extracts from p. grandiflorm（ ≤ 1 mg/mL）, but it was inhibhed by high concentration of the aequatie extracts （5 -20 mg/mL） ; the growth of the roots parts of wheat seedlings was in- hibited by the acquatic extracts, and the effect was more intensively compared to the aerial parts of wheat seedlings. As treated concen- tration increased, POD activity, proline content and MDA content of seedlings increased gradually; CAT activity, root activity and pig- ments content increased firstly and then dropped down; soluble protein and injury rate decreased firstly and then increased. AUelopathy of aquatic extracts from P. grandiflorum plants on wheat seedlings was positive promotion at low density and negative inhibition at high density, wheat could be cropped for rotation with P. grandiflorum.