两种羟基苯乙酸对大豆萌发的化感效应研究

通过田间和室内试验相结合，利用高效液相色谱检测大豆根际土境和残茬腐解液中的对羟基苯乙酸和间羟基苯乙酸的含量；在培养皿内研究两种酚酸对大豆生长抑制效应；研究了二者对大豆DNA熔点(Tm)的影响，并采用SDS—PAGE方法研究二者对根系蛋白合成的影响．结果表明，在大豆根际土境和残茬腐解液中检测到对羟基苯乙酸；两种羟基苯乙酸处理后，大豆例根效和主根长均显著减少，表现出明显的化感抑制效应，间羟基苯乙酸的抑制效应更明显；两种羟基苯乙酸使大豆DNA的熔点(Tm)下降，一些小分子蛋白的合成受到影响，从而抑制大豆生长，表现出典型的化感效应。

Allelopathic effect of p-and m-hydroxy-phenylacetic acid on soybean (Glycine max L) germination

In present work the p-hydroxy-phenylacetic acid (PHPA) and m-hydroxy-phenylacetic acid(MHPA) in rhizospheric soil solutions and decomposed root residues were detected by High Performance Liquid Chromatography (HPLC), and their effects on soybean germination at the level of 0, 30, 60, 150, 300 and 600 mg.kg-1, on melting temperature of DNA at the level of 600 mg.kg-1 and on cytoplasm protein patterns at the level of 0, 30, 150, 300 mg.kg-1 were also studied. PHPA and MHPA were detected in decomposed products of root residue and soil solutions collected from rhizosphere in which soil sickness was occurred, but not detected in soil on which soybean rotated with wheat. The standard samples of PHPA and MHPA were used for bioassay in Petri dish. The main root length and lateral root number of soybean were seriously reduced, even at the level of 30 mg.L-1. Soybean germination and root growth were retarded seriously by MHPA, in contrast with PHPA. At the level of 600 mg.kg-1, the melting temperature (Tm) of soybean DNA was increased sharply from 77 degrees C to 84.5 degrees C with PHPA, and from 77 degrees C to 88.5 degrees C with MHPA. Tm was affected markedly by MHPA, compared to PHPA, and the result was consistent with that of bioassay. The cytoplasm protein patterns of soybean leaves were obtained from SDS-PAGE, showing several low weight molecular proteins were affected, especially on 16. 1 kD and 20.2 kD. The results implied that PHPA and MHPA had allelopathic effect on soybean, and might have a role in soil-sickness of soybean.