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盐碱地是潜在的可利用耕地资源,但土壤盐碱化严重制约了农业生产的可持续发展。基于棉花机械化程度低、劳动力成本和生产资料投入剧增、比较效益下降和实施粮食生产安全战略等因素影响,我国长江流域和黄河流域棉花面积锐减,种植区域向内陆盐碱旱地或滨海盐碱地转移,但目前针对盐碱地转Bt基因棉种植可能带来的生态安全性问题研究甚少,正成为国内外研究的焦点和热点。伴随着棉花向盐碱地大面积转移种植趋势,检测盐胁迫是否影响转基因抗虫棉抗虫性,明确其影响程度,直接关系到转基因抗虫棉种植的安全性,也是目前抗虫棉扩大生产中迫切需要解决的问题。以非转基因棉花为对照,分别在低盐、中盐和高盐土壤种植的棉花的苗期、蕾期和花铃期采样,室内测定了转Bt基因棉花叶片对棉铃虫幼虫校正死亡率和外源蛋白表达量。研究结果发现盐分胁迫下转Bt基因棉花苗期叶片对棉铃虫幼虫校正死亡率下降了9.22%—47.46%,蕾期下降了31.61%—45.42%,花铃期下降了3.59%—18.52%;土壤盐分显著降低了转Bt基因棉花叶片中外源蛋白的表达量,苗期功能叶外源蛋白表达量下降了7.66%—29.86%;蕾期下降了3.77%—36.85%;花铃期下降了18.13%—41.02%;相关性分析表明,盐分胁迫条件下转Bt基因棉花叶片中外源蛋白表达量与其对棉铃虫抗性程度存在正相关关系。结果表明,盐碱土壤显著降低了转Bt基因棉花叶片外源杀虫蛋白表达量,从而导致转Bt基因棉花叶片对棉铃虫的抗虫性下降。研究土壤盐分对转Bt基因棉花对棉铃虫的影响及其作用机制,可为建立盐碱地转Bt基因棉花田害虫综合防控技术体系、转Bt基因棉花环境安全评价及转Bt基因棉安全管理提供依据。
Saline-alkali land is a potential source of arable land, but soil salinization severely restricts the sustainable development of agricultural production. Due to the low degree of mechanization of cotton, the sharp increase in input of labor costs and means of production, the decline of comparative benefits and the implementation of food production safety strategy, the area of cotton in the Yangtze River and Yellow River valleys in China dropped sharply. The planting areas moved to inland saline-alkali dry land or coastal saline- However, little research has been done on the ecological security brought by Bt cotton planting in saline-alkali soils at present, which is becoming the focus of research at home and abroad. With the trend of cotton transferring to a large area of saline-alkali soils, it is urgent to test whether the salt stress affects the insect resistance of transgenic Bt cotton and to clarify its influence degree, which is directly related to the safety of transgenic Bt cotton planting. issues that need resolving. Cotton samples were planted in low, medium and high salt soils at the seedling, budding and bollwering periods respectively. The corrected mortality of cotton bollworm (L.) Source protein expression level. The results showed that the corrected mortality of H. armigera larvae decreased by 9.22% -47.46%, the bud stage decreased by 31.61% -45.42%, and the flower-boll stage decreased by 3.59% -18.52% Salinity significantly reduced the expression of foreign proteins in Bt transgenic cotton leaves, the expression of foreign protein decreased by 7.66% -29.86% at seedling stage, decreased by 3.77% -36.85% in bud stage and decreased by 18.13% -41.02%. Correlation analysis indicated that there was a positive correlation between the expression level of foreign protein and the resistance to H. armigera in transgenic Bt cotton under salt stress. The results showed that saline-alkali soil significantly reduced the exogenous insecticidal protein expression in transgenic Bt cotton leaves, which resulted in the decrease of insect resistance of cotton leaves to Bt cotton. Studying the effect of soil salinity on cotton bollworm and its mechanism of transgenic Bt cotton can provide a basis for the establishment of a synthetic control system for insect pest insecurity in transgenic Bt cotton fields from Saline-Alkali Land, safety evaluation of transgenic Bt cotton and safety management of transgenic Bt cotton .