氯化钾对玉米根系糖和酚酸分泌的影响及其与茎腐病菌生长的关系

通过溶液培养试验，研究了氯化钾（KCl）对不同抗性品种玉米根系糖和酚酸分泌量的影响，以及在不同浓度糖和酚酸的培养基上禾谷镰刀菌（Fusarium graminearum Schwabe）的生长状况，探讨KCl抑制玉米茎腐病发生过程中，根系分泌物中糖和酚酸所发挥的作用。结果表明，感病品种吉单327的总糖、还原糖和其蔗糖分泌量均高于抗病品种吉单180；正常供钾条件下，总糖、还原糖和蔗糖的分泌量均表现出不同程度的下降，且还原糖下降幅度最大。阿魏酸和绿原酸是玉米根系分泌物中主要的两种酚酸组分。抗病品种吉单180分泌的阿魏酸量明显高于感病品种吉单327，而绿原酸分泌量低于吉单327。正常供钾时，阿魏酸分泌量明显增加，但绿原酸分泌量则有所减少。一定浓度的蔗糖和葡萄糖均能显著促进F. graminearum的生长，且还原糖（葡萄糖）的促进效果较蔗糖更明显；阿魏酸和绿原酸均能抑制F. graminearum的生长，但阿魏酸的抑制效果远远高于绿原酸。KCl 可明显减少不同抗性品种玉米根系的还原糖分泌量，增加阿魏酸的分泌，从而一定程度上抑制了病原菌F. graminearum在根际的快速生长。

Effect of potassium chloride on the exudation of sugars and phenolic acids by maize root and its relation to growth of stalk rot pathogen

Hydroponic experiment and incubation experiments were conducted to study the effect of potassium chloride on the exudation of sugar and phenolic acids, and the effects of major components in sugar and phenolic acids on the development of Fusarium graminearum Schwabe. The results showed that the amount of total sugar, reducing sugar and sucrose exudates by root of resistant cultivar was lower than that by root of susceptible cultivar. Potassium supply decreased exudation of total sugar, sucrose and reducing sugar in different extent significantly, especially reducing sugar. The amount of ferulic acid exudates by root of resistant cultivar was higher than that of susceptible cultivar significantly, while a reverse trend was found in chlorogenic acid. In vitro, the growth of F. graminearum was stimulated by sugar and inhibited by ferulic acid and chlorogenic acid. While the suppression effect of ferulic acid was more effective than chlorogenic acid. In conclusion, the decrease of reducing sugar content and the increase of the amount of ferulic acid in seedling root exudates with potassium supply may help to inhibit F. graminearum growth in rhizosphere.