Effects of Root Exudates from Watermelon, Rice Plants and Phenolic Acids on Fusarium oxysporum f. sp. niveum
Effects of Root Exudates from Watermelon, Rice Plants and Phenolic Acids on Fusarium oxysporum f. sp. niveum
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发表时间：
2010
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通讯作者：
Hao WenYa;R. Wei;S. Qirong;Ren Lixuan
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作者：
Hao WenYa;R. Wei;S. Qirong;Ren Lixuan
[目的]为了比较西瓜和水稻根系分泌物中的化感物质对FON生长的影响，阐明间作系统中抑制FON的机理。[方法]用营养液培养法采集西瓜和水稻的根系分泌物，用培养基法测定它们对FON的影响。用高效毛细管电泳法鉴定REW和RER中的酚酸，并用外源酚酸考察了REW和RER中存在的一些酚酸对FON的影响。在0.1~2.0毫升的浓度范围内，添加1.0毫升和5.0毫升的REW可使孢子萌发率分别提高46.9%和59.2%，使孢子萌发率提高10.8%~84.6%；添加1.0毫升和5.0毫升的RER使孢子萌发率分别下降14.3%和6.1%，而在0.1~2.0毫升的浓度范围内，REW的添加量降低4.6%~37.5%。Rew和REW中均含有对羟基苯甲酸和邻苯二甲酸，而REW和REW中仅检出阿魏酸和p-香豆酸。此外，在RER中，对香豆酸的含量最高，占酚酸总量的37.9%，是REW的1.4倍。从外源酚酸对FON孢子萌发、孢子繁殖和菌丝生长的影响来看，p-香豆酸的抑制作用最显著，其次是水杨酸与对照相比，外源p-香豆酸使孢子萌发率降低9.1%~70.5%，孢子繁殖率降低24.1%~100.0%，菌丝生长量降低2.5%~47.5%。阿魏酸具有明显的促生作用，浓度在40~160mg.L-1时，可促进孢子萌发28.6%~114.3%，促进孢子繁殖17.7%~54.8%。[结论]水稻根系分泌物具有抑菌作用，而西瓜根系分泌物具有致病作用，为阐明西瓜/旱作间作西瓜抑病机理提供了科学依据。
【Objective】 The objectives of this study were to compare influence of allelochemicals from root exudates of watermelon and rice plants on the growth of FON and to clarify the mechanism of disease suppressiveness in the intercropping system.【Method】 Root exudates of watermelon(REW) and rice(RER) plants were collected by nutrient solution culture.The effects of REW and RER on FON were determined by culture medium method.The phenolic acids of REW and RER were identified by HPLC.Exogenous phenolic acids were also used to investigate the effect of some phenolic acids,which existed in REW and RER,on FON.【Result】Compared with the control,addition of 1.0 mL and 5.0 mL of REW increased the numbers of germinating spores by 46.9% and 59.2%,respectively,while the spore reproduction was enhanced by 10.8% to 84.6% when REW was added in the range from 0.1 to 2.0 mL.In contrast,addition of 1.0 mL and 5.0 mL of RER decreased spore germination by 14.3% and 6.1%,respectively,while addition of REW from 0.1 mL to 2.0 mL decreased spore reproduction by 4.6% to 37.5%.Salicylic acid,p-hydroxybenzoic acid and phthalic acid were identified in both RER and REW by HPLC analysis,but ferulic and p-coumaric acid acid were detected exclusively in REW and RER,respectively.Moreover,the content of p-coumaric acid was the highest among phenolic acids in RER,accounting for 37.9% of the total amount of phenolic acids,which was 1.4-fold as high as that in REW.According to the effects of exogenous phenolic acids on spore germination,spore reproduction and mycelial growth of FON,p-coumaric acid had the most significant inhibitory effects,followed by salicylic acid.In detail,exogenous p-coumaric reduced spore germination by 9.1% to 70.5%,spore reproduction by 24.1% to 100.0% and mycelial growth by 2.5% to 47.5%,as compared with the controls.In contrast,ferulic acid,p-hydroxybenzoic acid and phthalic acid increased spore germination and spore reproduction to some extent.Among of them,ferulic acid had the obvious promoting effects and could enhance spore germination by 28.6% to 114.3% and spore reproduction by 17.7% to 54.8% when its concentration ranging from 40 to 160 mg.L-1.【Concluion】 It was concluded that the root exudates from rice plants were fungistatic while those from watermelon were pathogen-promotive.This finding provided a scientific basis for clarifying the mechanism of disease suppressiveness of watermelon in the watermelon/aerobic rice intercropping system.