濒危植物长叶红砂适应盐胁迫的生理生化机制研究

以濒危盐生植物长叶红砂(Reaumuria trigyna)幼苗为材料,研究了不同浓度NaCl溶液(0、100、200、300和400mmol/L)处理30d对其生长和生理生化指标的影响,以分析长叶红砂的耐盐生理机制。结果表明:(1)100和200mmol/L NaCl处理时,长叶红砂鲜重和干重均显著增加,但随着盐浓度继续增加,长叶红砂幼苗生长受到抑制,且地上部受到的抑制大于根部,显示长叶红砂适宜生长的NaCl浓度是200mmol/L。(2)随NaCl胁迫浓度的升高,长叶红砂的净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)呈下降趋势,胞间CO2浓度(Ci)呈上升趋势,说明光合速率的下降使利用CO2的能力下降,胞间积累了大量的CO2,且盐处理浓度越高量越大。(3)随NaCl胁迫浓度的升高,长叶红砂幼苗Na+、Cl-含量增加,可溶性糖、脯氨酸、游离氨基酸及可溶性蛋白等有机渗透调节物质的合成增加。研究认为,长叶红砂是通过调节叶片Na+、Cl-以及有机渗透调节物质含量来提高其耐盐能力。

Physiological and Biochemical Mechanisms of an Endemic Halophyte Reaumuria trigyna Maxim.under Salt Stress

Reaumuria trigyna seedings were treated with NaCl of different concentrations(0,100,200,300 and 400 mmol/L) for 30 days.A study about its growth,physiological and biochemical mechanisms in different NaCl concentrations showed:(1)Under 100 and 200 mmol/L NaCl stress,the fresh weight and dry weight increased significantly than that of control.Growth of R.trigyna was inhibited with increasing NaCl concentrations,showing that the suitable NaCl concentration of R.trigyna seedlings growth was 200 mmol/L.(2)Pn,Tr and Gs decreased and Ci increased,showing decrease of photosynthesis rate causing reduction of utilization rate and intracellular CO2 accumulation which was higher when NaCl concentration was higher.(3)Osmotic adjustments of R.trigyna mainly relied on Na+ and Cl-,soluble sugar,free amino acid,proline and soluble protein.This study discovered that R.trigyna could improve its salt tolerance ability by adjusting Na+ and Cl-content and osmosis regulating substances in leaves.