Responses of Grassland Invertebrates to Management by Cutting. V. Changes in Hemiptera Following Cessation of Management

Abstract

The decline of disease resistance of transgenic insect-resistant cotton has become one of the important factors restricting China cotton production. With two transgenic insect-resistant cotton varieties and their parental conventional cotton lines as test materials, the effects of their root exudates on the spore germination and mycelial growth of Verticillium dahliae Kleb were studied, and the components and contents of the amino acids and sugars in the exudates were determined. Comparing with their parental lines, the two transgenic insect-resistant varieties had a declined resistance against V. dahliae, and their root exudates had promotion effects on V. dahliae spore germination and mycelial growth. The root exudates of transgenic cotton Zhong-41, compared with those of its parent line Zhong-23, contained two additional amino acids Met and Lys, and the contents of Asp, Glu, Ser, Ala, Val, Leu, and Tyr were significantly higher. Though the components of amino acids in the root exudates of Simian-3 and transgenic cotton GK-12 were the same, the Tyr, Val, and Leu contents in the root exudates of transgenic cotton GK-12 were significantly lower. Four kinds of sugar were detected in the root exudates of Zhong-41, while only glucose was detected in the root exudates of Zhong-23. These four kinds of sugar were also detected in the root exudates of Simian-3 and GK12, but their contents differed significantly.