转Bt基因棉叶片腐熟物抑制AM真菌定殖及菌根对磷的吸收

摘要

转Bt基因棉对土壤微生物生长、群落结构及生理生态功能的影响备受关注.笔者于盆栽条件下比较了Bt棉(中41、晋44)与常规棉(中23、冀492)叶片腐熟物对丛枝菌根(AM)真菌异形根孢囊霉Rhizophagus irregularis在紫云英Astragalus sinicus根部定殖及其部分生理功能的影响.结果表明,与常规棉处理相比,Bt棉叶片腐熟物显著抑制了AM真菌在紫云英根部定殖,根段侵染率、侵染强度及丛枝丰度下降;Bt棉叶片腐熟物抑制了AM真菌琥珀酸脱氢酶和碱性磷酸酶活性;菌丝中多聚磷酸盐相对含量、紫云英地上地下部分磷吸收量显著降低.结论认为Bt棉叶片腐熟物抑制了AM真菌在植物根部的定殖,降低了AM真菌的共生效应,这可能影响到AM真菌的生态功能.%The impact of transgenic Bt cotton Gossypium hirsutum on soil microbial growth,community structure,and physiological and ecological functions was greatly concerned.In this study,a pot experiment was conducted to evaluate the impact of composted leaves of Bt cotton on symbiotic characteristics and physiological functions of arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis.The results showed that the composed leaves of Bt cotton (Zhong41 and Jin44) reduced mycorrhizal colonization rate,colonization intensity and arbuscule frequency in roots of Astragalus sinicus as compared with the corresponding traditional cotton (Zhong23 and Ji492).The activities of succinate dehydrogenase and alkaline phosphatase of AM fungus decreased.The polyphosphate granules in intracellular hyphae and the content of phosphorusin the aerial and underground part of A.sinicus reduced with the treatments of the composted leaves of Bt cotton.The results indicated that the composted leaves of Bt cotton had an inhibitive effect on the symbiotic characteristics and physiological functions of AM fungus R.irregularis,which could depress the ecological functions of the plant-fungus symbiosis.