Effect Of Transgenic Corn On Collembola

Transgenic corn was modified to combat lepidopteran pests, herbicide and otherdeteriorate environmental factors. Jilin is one of the most important regions for cornproduction. However, fewer studies concerned the effects of transgenic corncultivation on the soil Collembola in black soil region in China. Four experimentsincluding three scales were taken into acount to investigate the effect of transgeniccorns on Collembola. The main results are listed as followed:1. Effect of transgenic corn cultivation on the abundance, species richness anddiversity of CollembolaSix corn varieties including three pairs of transgenic ones and their near-isolines(Bt38and Z58, Mon89034and NC6304, and C63and ZD958) and two samplinglocations were deployed to study the effect of transgenic corn cultivation andsampling location on densities, species richness and community structure ofCollembola.Compared with transgenic varieties of Bt38and C63, Bt corn cultivation did notsignificantly affect abundance, species richness and community structure. Some rareisotomids of the genera Desoria and Folsomia were only recorded in non-Bt cornvarieties but not in Bt corn varieties. The feeding experiments of corn leaves showedthat survival and reproductive rate of Folsomia candida did not differ in Bt andnon-Bt corn varieties of senescent and fresh corn leaves after two months feedingbehaviours.In Mon89034and NC6304corn varieties, we found that Collembolasignificantly affected by sampling location treatments. Densities and species richnessof collembolans significantly decreased in ‘between plants’ than in ‘rizhosphere’.Densities of Collembola were impacted by corn varieties. In the whole growingseason, densities of Collembola significantly decreased in NC6304than in ZD958. Collembolans of transgenic variety only slightly decreased in ‘jointing stage’ than ZD958. Collembolans adversely affected in ‘between plants’ when compared to ‘inrhizosphere’ in ‘seeding stage’ but not other stages.These variations of collembolans were in lines with the trend of corn rootbiomass. It is indicated that Collembola variations could be caused by food resources(root biomass) but not corn varieties (transgenic one and control).2. Effect of transgenic corns cultivation and litter decomposition on CollembolaFour treatments including two transgenic varieties and their near-isolines (Bt38and Z58, Mon89034and Z58) were deployed to investigate the effect of transgeniccorn cultivation and leaves decomposition on Collembola.The number of F. candida significantly decreased in transgenic Bt38corn varietywhen compared to non-Bt variety Z58. As for transgenic variety Mon89034, Bt corncultivation did not significantly affect abundance of Folsomia candida. It wasindicated that effect of transgenic corn cultivation on non-target organisms wouldalter with the corn varieties.Proisotoma minuta was a dominant species in all the corn litter treatments. Whencompred to non-Bt variety Z58, total number of collembolans extracted from Bt38corn litters significantly decreased. While decomposition of transgenic cornMon89034did not affect abundance, species richness and diversity of Collembolan.The number of Thalassaphorura macrospinta and Folsomia sp1significantlyincreased in transgenic corn Mon89034than non-Bt variety NC6304. It is in line withthe trend of transgenic corn cultivation through root-derived way.3. Effect of litter feeding (leaves and pollen) of transgenic corns on F. candidaFour treatments including two transgenic varieties and their near-isolines (Bt38and Z58, Mon89034and Z58) were deployed to investigate the effect of leaf litter andpollen feeding on F. candida.The feeding experiments of corn leaves showed that survival and reproductiverate of F. candida did not differ in Bt38and Z58of senescent and tender corn leaves after two months feeding. While feeding on transgenic corn (Mon89034) leaves, thenumber of F. candida significantly increased when compared to non-Bt varietyNC6304.The number of F. candida significantly decreased in Bt38treatment than non-BtZ58when feeding on corn pollen.It was indicated that feeding effect of transgenic corn on non-target organismswould alter with the corn varieties and litter qualities.