从地下的角度分析膜下滴灌棉花发生早衰的可能机制

A Review About the Possible Mechanism of Cotton Premature Senescence Under Drip Irrigation Below Mulch Film from the Perspective of Underground

在膜下滴灌条件下,棉花早衰问题严重。在对国内外关于棉花早衰研究成果及膜下滴灌条件特殊根区微环境深入分析的基础上,提出了膜下滴灌棉花早衰原因的合理假设,认为不合理的根系构型及其高蕾铃负荷是造成膜下滴灌棉花早衰的根本原因:膜下滴灌条件下棉花根系生长和构型分布发生的明显变化不利于棉花根系吸收土壤深层的水分和养分,抗逆性减弱,对环境的改变无法做出及时的反应,加之覆膜增温及优越的水肥供应,棉花地上部生长良好,蕾铃负担增加,一旦遇到逆境条件,在高蕾铃负荷前提下,即使对根系养分吸收功能最轻微的损害或者暂时的养分供应短缺均有可能造成对地上部养分供应的不足并发生早衰。因此,如何通过调控构建与地上部生长更为匹配的、构型分布更加合理的、抗逆性更强的棉花根系就成为解决膜下滴灌棉花早衰问题的关键。

There were more reports about cotton premature senescence under drip irrigation below mulch film（DI） in recent years. In this paper,a summary about the research results of cotton premature senescence in domestic and international was made,and then combination the analysis of the root zone special micro-environment under DI,we considered the premature senescence under DI was attributable to change of the cotton root growth and distribution coupled with the high boll load：the cotton root growth and distribution showed a significant configuration changes（increase in the number of lateral roots,main root degradation,shallow root distribution） under DI. So the root system of plants couldn＇t respond rapidly to environmental change. On the other hand,shoot growth of cotton was better under DI due to warming and superior coated fertilizer supply,and there were more boll so that the premature senescence were likely to occurrence due to lack of shoot nutrient supply in the event of adverse conditions. Therefore,we believed that would be the key to solve the problem of cotton premature senescence under DI was to build a cotton root system which more matched with shoot growth,and conformation distribution was more reasonable,more resistance to environmont.