[Effects of selenium on soybean chloroplast ultra-structure and microelement content of soybean leaves under...

Pot and field experiments were carried out to study the effect of low Se concentration on soybean chloroplast ultra-structure and on Mg, Fe, Mn and contents in soybean leaves under continuous cropping stress. The results showed that Se could certainly increase the contents of Mg, Fe and Mn in soybean leaves when the application rate of Se was below 0.50 mg.kg-1 in pot experiment, and below 300 g.hm-2 in field experiment. In pot experiment, Se concentration positively correlated with Mg and Fe contents in soybean leaves, but the relationship between Mn and Se was hardly to be quantified. Transmission electron microscopic observation indicated that under continuous cropping stress, application of Se could hold the soybean chloroplast membrane structure in good condition. When Se was not applied, the chloroplast swelled, and its grana disappeared, and even, transformed into etioplast. These experiments indicated that application of low Se could alleviate peroxidative stress resulting from continuous cropping, and keep the soybean grow normally.