| In contrast with the international and common-used salt-tolerant species, Lee68, the salt tolerance of some annual G. sop L. (including halophyte and glycophyte) and G. max L. in phases of seed germination and seedling was compared and identified. The effects of light (-0.5 5MPa) and heavy (-1.1 OMPa) iso-osmotic stress (Na~,CU and NaC1) on seed germination rate, growth of seedlings, electrolytic leakage and contents of chlorophyll and carotenoids in leaf were studied on the aspect of salt ion injury. The results showed that the salt tolerance of soybeans in germination phase was not interrelated to that in seedling phase, although the salt tolerance of BB52 and Lee68 was higher both in seed germination and seedling. Under light iso-osmotic stress, the inhibition of Na~ on seed germination was more than that of CU, which was contrary to that under heavy iso-osmotic stress. In phase of seedlings, Na~ and CU were all toxic ions of salt injury in soybean, the toxicity of Cl was stronger than that of Na~, and the NaCI treatment expressed enhancing effect. The surfaces of stem and leaf of the G.soja L. (BB52) seedlings under salt solution and salt soil culture, and the adult plants under field culture, were observed and compared by scanning electron microscope (SEM). The results showed that, the salt glands was not found in the seedlings, but on the surfaces of stern and leaf in the adult plants, the globular structure was found with the diameter of 2.72?.22 and 4.08?.61 ~tm, respectively. Compared to the G. max L. (Lee68, the salt tolerant) and the G. soja L. (N23232, the salt sensitive), the effects of salt stress on growing rate, electrolytic leakage, ion absorption, transportation and distribution, metabolism of active oxygen, the contents of polyamines (PAs), proline and soluble sugar, were studied with flame spectrophotometer, X-ray microanalysis, leaf feeding of DNa, thin-layer chromatography (TLC) and the fluorescence detection, etc. The inhibition of growth and increase of electrolytic leakage in BB52 seedlings were the least. Under NaC1 stress for short time (12h) and long time (30d), the Na~ and CU absorbed by its roots were less transported to the upper part of the seedlings, especially to the leaves, but the selectivity of K~ was stronger, the above mentioned led to lower Na~/K~ ratio in its leaves, although more Na~ and CU were absorbed by S its roots. After removing l5Ommol.U?NaCI stress for lOh from root, the absorbed Na~, Cl by BB52 seedlings were mainly remained in root or re-transported to the root-stem juncture. The content of absorbed 22Na in BB52 was more than that in N23232 after 4 leaf feeding of 22Na for 1 Oh, and more of absorbed 22 in BB52 was re~transported to its root, and less to its upper parts of the seedlings, especially for the heart leaf The situation in N23232 was opposite. Under 150 and 300 mmol.U?NaCI stressed for 2d, the O2~ contents in root and leaf of BB52 seedlings decreased, the superoxide dismutase (SOD) and the leaf ascorbate peroxidase (APX) activities all increased , as compared to the control plants. Under I 5Ommol.U?NaC1, the malondialdehyde (MDA) contents in root and leaf of BB52 showed no obvious ascent, but under 300mmolJJ1 NaC1, they were increased significantly, and the increasing range in BB52 was less than those in Lee68 and N23232. The contents of vitamin C (...
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