干旱胁迫与外源激素PDJ对不同基因型小麦化感潜力的诱导调控

Inducible regulation of allelopathic potential in different wheat genetypes under drought and prohydrojasmon (PDJ) treatment

盆栽条件下对4个不同基因型小麦品种于播种前以外源激素PDJ(10mg·L-1)浸种处理和返青期始干旱胁迫,测定其光合特性、水分利用和化感抗草差异。结果表明:水分胁迫(田间持水量的45%)和PDJ处理均能增强几种供试小麦的化感抗草诱导效应,两者均通过降低杂草生物量从而抑制杂草生长。水分胁迫和PDJ处理均能增强"兰考95-25"、"小偃6号"拔节期的叶片光合速率,降低气孔限制值和提高水分利用率;"豫麦66"PDJ处理下可增强光合作用而降低水分利用率,但干旱胁迫下则相反;"兰考217"经PDJ处理光合速率和水分利用率均降低。典范对应分析发现供试小麦受到干旱胁迫和外源激素PDJ处理后会引起植物形态和光合生理的变化,从而影响其化感抗草特性。小麦整体化感潜势与以杂草生物量(杂草鲜重/盆)表示的抗草指标显著相关,而小麦的整体抗草特性主要与其水分利用率、光合速率和蒸腾速率显著正相关,与植物地上生物量、株高、节间距离和气孔导度显著负相关。

In a pot experiment, growth adaptation of four winter wheat （Triticum aestivum L.） accessions was investigated following seed pretreatment by soaking with prohydrojasmon （a kind of exogenous hormone at 10 mg·L^-1） before sowing. The seeds were subjected to artificial soil water regulation at 75% and 45% field capacity at the start of greening. Also in the experiment, the photosynthesis level, water use, variation of weed-controlling effect of allelopathy of wheat under acclimatized soil water and PDJ treatment was conducted. Soil drought and PDJ were used to stimulate the overall allelopathic inhibition and weed-resistance of wheat in the pot trial. The study shows that physiological response of ＂Lankao 95-25＂ and ＂Xiaoyan 6＂ to water shortage and PDJ is significant due to enhanced leaf net photosynthetic rate, water use efficiency and stoma capacity. Under PDJ, photosynthetic rate of ＂Yumai 66＂ obviously increases. However, water use efficiency decreases, while drought stress has just the opposite effect on ＂Yumai 66＂. Under PDJ treatment, leaf net photosynthetic rate and water use efficiency of ＂Lankao 217＂ decrease. Based on Canonical Correspondence Analysis （CVA）, water deficit and PDJ change the phenotype and photosynthetic physiology of plants, consequently influencing weed-controlling effect of allelopathy. On the average, allelopathic potential in intact wheat plants has a significant correlation with wheat weed-resistance expressed with weed biomass. Wheat weed-resistance characteristics are significantly directly related with wheat photosynthetic rate, transpiration rate and water use efficiency. However, they are significantly inversely related with aboveground biomass, plant height, node distance and stoma conductance.