枯萎病菌侵染后间作小麦对西瓜生理指标的影响

Effects of intercropping with wheat on watermelon physiological parameters after Fusariu oxysporum f. sp. niveum infection

为了探讨间作小麦提高西瓜枯萎病抗性的生理机制,采用西瓜品种‘早佳’(8424)和小麦品种‘鄂麦18’为试验材料,设置西瓜单作(M)、西瓜单作+FON(MF)、西瓜与小麦间作(I)、西瓜与小麦间作+FON(IF)共4个处理,研究间作小麦和接种西瓜专化型尖孢镰刀菌对西瓜生理生化指标的影响。结果表明,接种FON 15 d时,间作小麦与单作相比,西瓜叶片净光合速率、胞间CO2浓度和气孔导度分别升高6.98%、15.52%和36.88%,西瓜根系β-1,3-葡聚糖酶和几丁质酶活性分别升高14.09%和11.85%,根系类黄酮和总酚含量分别增加13.03%和21.31%,根系MDA和H2O2含量分别降低5.49%和11.56%,均达到显著差异水平;接种FON 25 d时,小麦间作与单作相比,西瓜叶片净光合速率、胞间CO2浓度和气孔导度分别升高5.40%、9.92%和30.23%,西瓜根系β-1,3-葡聚糖酶增加81.11%,根系类黄酮和总酚含量分别提高51.89%和15.03%,根系MDA和H2O2含量分别降低6.69%和12.43%,均差异显著。总之,接种FON后,与单作西瓜相比,小麦间作提高了西瓜叶片光合能力,增加根系次生代谢产物的积累,降低了膜脂过氧化程度的伤害,有助于增强西瓜植株的抗病性。

To explore the physiological mechanism of wheat intercropping improves the resistance of watermelon to Fusarium wilt,watermelon variety ’Zaojia’(8424)and wheat variety‘Emai 18’as test materials were conducted to investigate the effects of wheat intercropping and inoculation Fusarium oxysporum f. sp. niveum(FON)on physiological and biochemical parameters in watermelon in four different treatments(watermelon monocropping(M),watermelon monocropping with FON inoculation(MF),watermelon/wheat intercropping(I),and watermelon/wheat intercropping with FON inoculation(IF)).The results showed that photosynthetic rate,intercellular CO2 concentration and stomatal conductance of watermelon leaf in intercropping with wheat were significantly higher than those of monoculture watermelon on the 15 th day after inoculation with FON by 6.98%,15.52% and 36.88%,respectively. The activities of β-1,3-glucanase and chitinase in watermelon roots in intercropping with wheat were significantly higher than those of monoculture watermelon on the 15 th day after inoculation with FON by 14.09% and 11.85%,respectively. The flavonoid and total phenolic contents of watermelon root in intercropping with wheat were also significantly higher than those in monoculture watermelon on the 15 th day after inoculation with FON by 13.03% and 21.31%,respectively. The MDA and H2O2 contents of watermelon root in intercropping with wheat were significantly lower than those in monoculture watermelon on the 15 th day after inoculation with FON by 5.49% and 11.56%,respectively. Similar results were obtained on the 25 th day after inoculation with FON for photosynthetic rate,intercellular CO2 concentration and stomatal conductance of watermelon leaf,β-1,3-glucanase activity and flavonoid and total phenolic contents of watermelon root in intercropping with wheat,all of which were significantly higher than those in monoculture watermelon by 5.40%,9.92%,30.23%,81.11%,51.89% and 15.03%,respectively. The MDA and H2O2 contents of watermelon root in intercropping with wheat were significantly lower than those in monoculture watermelon on the 25 th day after inoculation with FON by 6.69% and 12.43%,respectively.In conclusion, compared with watermelon monoculture,the capacity of photosynthetic of watermelon leaf and secondary metabolites in watermelon root were increased,the damage of membrane lipid peroxidation was reduced in intercropping with wheat system after inoculation with FON. The wheat intercropped with watermelon was beneficial for increasing disease resistance of watermelon plant.