【摘要】 为了明确棉花库源比(铃叶比)变化对红叶茎枯病发生的影响,揭示红叶茎枯病的病因,本研究开展了多项试验。试验结果显示,棉株的病害严重度与其铃叶比呈高度正相关。早熟品种开花期早,铃叶比高,病害发生重;盛蕾期以前的气温对棉花生长和红叶茎枯病发生的作用大于土壤水分的作用。与常温处理相比,提高棉花3叶期至盛蕾期的气温,可促进棉花的营养生长,减小库源比,其发病盛期延后约45 d,病情指数平均减少72.9%,棉花生物学产量平均提高123.8%;去蕾和推迟打顶均可降低棉花铃叶比,减轻病情,以去全蕾处理的作用最为明显;叶面喷施甲哌鎓可提高棉花铃叶比,利于病害发生。因此,铃叶比失调是红叶茎枯病的主要病因;开花期以前棉花代谢源(叶)的生长量决定着病害发生的时间和严重度。更多还原

【Abstract】 In order to elucidate the cause of cotton red leaf disease,a series of experiments were conducted to study correlation between sink /source( boll /leaf) ratio and the disease severity. The results showed that the grades of the diseased plants were positively correlated with their boll /leaf ratios significantly. The early-maturing cotton variety had an earlier flowering date,higher boll /leaf ratio and a more serious disease severity than those of the late-maturing one. The air temperature before full squaring date was found more important on cotton growth and the occurrence of red leaf disease than soil moisture. Compared to the normal temperature treatment,increasing air temperature from the 3rd leaf date to full squaring date promoted cotton vegetative growth and reduced the sink /source ratio,thus,the peak stage of the disease was postponed by about 45 days,the average disease index decreased by 72. 9% and the average biological yield of cotton increased by 123. 8%. Decreased boll /leaf ratio by removing squares and delayed topping could reduce the incidence of red leaf disease. The treatment of removing all squares from cotton plants resulted in the least disease severity. Foliar application of mepiquat chloride increased cotton boll /leaf ratio and was thus favorable to the development of red leaf disease.Those findings indicate that the imbalanced sink /source ratio is the main cause of red leaf disease in cotton. The growth of metabolic source( leaf) before flowering date determines the onset and the severity of the disease.更多还原