硅对盐胁迫下杨树根系中离子微域分布的影响

Effect of Silicon on Ion Distribution in Populus spp. Root Under Salt Stress

运用X-射线电子探针研究了硅对盐胁迫下杨树根系中离子微域分布的影响。结果表明:盐胁迫(NaCl)浓度分别为0 g/L、2 g/L、3 g/L、4 g/L处理使杨树苗根系表皮、皮层和中柱细胞中Na+、Cl-的X-射线峰明显升高,K+峰降低;而盐胁迫后加浓度为0.5 g/L硅处理后根系表皮、皮层和中柱细胞中Na+、Cl-的X射线明显降低,而K+峰则大幅度提高,Na+在根系各部分呈均匀分布。表明盐胁迫下水培杨树苗适当加硅可以改变其体内养分离子的吸收和离子分布,从而缓解了盐离子对杨树的毒害作用。

The effects of silicon on ion distribution in the root tips of Populus spp. under salt stress were studied with X-ray electron probe microanalysis. The results showed that the peak of Na ＋ and Cl^- in the cells of the epidermis, cortex and stele of Populus spp root under 2 g/L,3 g/L and 4 g/L NaCl stress was obviously higher compared with control while that of K^＋ was lower. However, after the addition of silicon 0. 5 g/L to the stressed plants, the contents of Na^＋ and Cl^- in those cells decreased remarkably while that of K^＋ increased significantly. Moreover, Na^＋ and Cl^- were distributed uniformly in all tissues of roots. It indicated that the addition of silicon under salt stress ameliorated the ion uptake and the ion microdistribution status, therefore, it alleviated the toxicity from salt ions.