[Determination of nutrient elements in transgenic insect-resistant cotton tissues by three different spectroscopical methods].

In order to find out the effects of exogenous genes, such as Bt and Bt coupled with CpTI, on nutrition metabolism in transgenic plants, totally eleven types of nutrient elements in transgenic Bt (Z30) and Bt-CpTI (CCRI41 and SGK321) cotton were determined using methods of flame atomic absorption spectroscopy, flame atomic emission spectroscopy and spectrophotometry at flowering stage and boll-opening stage. The results showed that the chemical composition of plant nutrition in transgenic insect-resistant cotton differed in comparison with non-transgenic cotton counterparts related to varieties, tissues and stages. The content of total N in transgenic cotton changed most significantly. Especially, it increased by 21% for transgenic Bt cotton Z30 compared to non-transgenic cotton Z16. These changes in total N content were probably caused by both transgenes expression in transgenic cotton and other processes not studied in this experiment. The content of Mg, Na and Cu in transgenic cotton varied significantly only in some certain varieties or tissues. It was unobvious how the incorporation of transgenes impacted on the content of organic C, total P, total S, K, Ca, Fe and Zn in transgenic cotton. The authors speculated that there were no significant changes in utilization and accumulation of these nutrient elements between transgenic insect-resistant cotton and their non-transgenic cotton counterparts (Z16, CCRI23 and SY321, respectively).