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采用盆栽实验方法,以新陆中36号(耐盐品种)和新陆中21号(盐敏感品种)为材料,从播种期开始进行NaCl胁迫,研究不同浓度NaCl胁迫(CK、0.6%、0.8%)下棉花幼苗生长、单株叶片叶面积、叶绿素含量、光合气体交换参数、游离脯氨酸含量(Pro)以及丙二醛含量(MDA)等的变化。结果表明,在0.6%和0.8%NaCl胁迫后,与对照(CK)相比,两品种棉花幼苗生长受到显著抑制,幼苗第一片真叶生长速度变慢,叶长、叶宽生长严重受阻、叶绿素含量(Chl)、净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、胞间CO_2浓度(Ci)等均呈现不同程度的下降;而游离脯氨酸及丙二醛等含量均增加。新陆中36号比新陆中21号受NaCl胁迫的影响程度较小,幼苗生长良好,表现出较好的耐盐性;光合速率下降的主要原因是低NaCl胁迫下气孔限制,而高NaCl胁迫下非气孔限制因素引起。幼苗第一片真叶对NaCl胁迫敏感,在NaCl胁迫条件下叶片生长受阻,两个棉花品种在叶片状态上出现的明显差异,可以作为筛选耐盐性品种的指标。
A pot experiment was carried out to study the effects of NaCl stress (CK, 0.6%, 0.8%) under NaCl stress at the beginning of sowing time with materials of Xinluzhong 36 (salt-tolerant variety) and Xinluzhong 21 (salt sensitive variety) %), Leaf area per plant, chlorophyll content, photosynthetic gas exchange parameters, free proline content and malondialdehyde (MDA) content of cotton seedlings. The results showed that under the stress of 0.6% and 0.8% NaCl, compared with CK, the growth of two kinds of cotton seedlings was significantly inhibited, the growth of the first true leaf of seedling was slowed down, the growth of leaf length and leaf width was severely hindered, Chlorophyll content (Pn), transpiration rate (Tr), stomatal conductance (Gs) and intercellular CO 2 concentration (Ci) all showed different degrees of decline. However, free proline and malondialdehyde Other content increased. Xinluzhong 36 was less affected by NaCl stress than Xinluzhong 21 and the seedlings grew well and showed better salt tolerance. The main reason for the decrease of photosynthetic rate was stomatal limitation under low NaCl stress and high NaCl Stresses caused by non-stomatal limitation. The first true leaf of seedlings was sensitive to NaCl stress, and the growth of leaves was blocked under the condition of NaCl stress. The obvious difference in the leaf status of the two cotton varieties could be used as an index to screen salt-tolerant varieties.