盐胁迫对盐芥生长及硝酸还原酶活性的影响

盐胁迫处理导致盐芥植株鲜重、干重、含水量、肉质化程度和根冠比都下降;根中有机物含量上升,而无机物含量下降,叶的变化与根的相反;渗透调节能力、Na 含量和根系活力上升;硝酸还原酶活性显著增加;超氧阴离子(O2-)含量先降低后升高.表面扫描电镜图像显示:盐芥叶片表面没有盐腺或盐囊泡,所以它不是泌盐盐生植物.盐芥生长状况、Na 含量和Na X-ray微区分析结果表明:盐芥也不是拒盐盐生植物,而很可能是稀盐盐生植物.

Effects of Salt Stress on the Growth and the Nitrate Reductase Activity in Thellungiella halophila

The results showed that when Thellungiella halophila was treated with NaCl, the fresh and dry weight, the water content, the succulency of whole plant and the root/shoot ratio were decreased (Figs. 2-4, 7); the organic matter content in roots was increased and the inorganic matter content in roots was decreased, while those in shoots changed in the opposite direction (Fig. 6); osmotic adjustment ability, the Na+ content, the root activity were increased (Figs. 5, 7, 8); the nitrate reductase activity increased significantly; the O(-)(2*) content decreased at about NaCl 50 mmol/L but increased at about NaCl 100-400 mmol/L (Fig. 10). The micrographs of T. halophila leaf surface by scanning electron microscope (SEM) indicate that there is no salt gland or bladder on the surface of T. halophila (Fig. 1), so it is not a salt-secreting halophyte. The determination of growth parameters, the Na(+) content and Na(+) X-ray (Table 1) microanalysis of T. halophila indicate that T. halophila is not a salt-exclusing halophyte but it probability is a salt-dilution halophyte.