关键词: 媒介话语意识, 媒介话语意识

Abstract: 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 be made, and then combination the analysis of the root zone special micro-environment under DI, we consider the premature senescence under DI is 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 cannot respond rapidly to environmental change. On the other hand, shoot growth of cotton is better under DI due to warming and superior coated fertilizer supply, and there are more boll so that the premature senescence are likely to occurrence due to lack of shoot nutrient supply in the event of adverse conditions. Therefore, we believe that will be the key to solve the problem of cotton premature senescence under DI is to build a cotton root system which more matches with shoot growth, and conformation distribution is more reasonable, more resistance to environmont.