烟草根系分泌的酚酸及自毒效应

Phenolic Acids in Nicotiana Tobacco L. Root Exudate and Their Autotoxicity Effects

对烟草根系分泌的酚酸及其自毒效应进行探讨,旨在为烟草连作障碍问题的解决提供科学依据。研究发现,烟草连作土壤中阿魏酸及肉桂酸含量较高。烟草根系分泌阿魏酸、肉桂酸、苯甲酸、香草酸、对羟基苯甲酸等酚酸,而阿魏酸的分泌速率是其他4种酚酸的6.8~365.0倍。阿魏酸(300~600μg/mL)显著抑制烟草种子的发芽和胚根的伸长。苯甲酸、肉桂酸、对羟基苯甲酸(100μg/mL)也显著抑制烟草胚根的生长。这些结果表明,根系分泌的酚酸是烟草的连作障碍物之一,而阿魏酸可能起主要作用。

Phenolic acids in Nicotiana tobacco L. root exudate and their autotoxicity were investigated in this study in order to provide scien- tific basis for solving obstacles of tobacco continuous cropping. The study revealed that soil collected from tobacco continuous cropping field contained greater amount of ferulie acid and cinnamic acid. Five phenolic acids including ferulic acid, cinnamic acid, p-hydroxybensoic acid, benzoic acid and vanillic acid were indentified in tobacco root exudates. And the secretion rate of ferulic acid was 6.8 to 365.0 times as high as that of cinnamic acid, p-hydroxybenzoic acid, benzoic acid and vanillic acid. Furthermore, ferulic acid （300 -600p^g/mL） sig- nificantly inhibited seed germination and radicle elongation of tobacco. Similarly, cinnamic acid, p-hydroxybenzoie acid, and benzoic acid （ 1001xg/mL） significantly inhibited radicle growth of tobacco. These results suggested that phenolic acids in tobacco root exudates were one of the factors restraining tobacco continuous cropping and ferulic acid may play an important role in the obstacles.