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基于控制试验研究了盐分对胡杨实生幼苗生长及光合特性的影响。结果表明:随着盐浓度增大,盐分对胡杨幼苗株高、基径及生物量影响明显,其程度大小为叶>根>茎。当土壤含盐量小于18.32g.kg-1(50mmolNaCl)时,该处理幼苗生物量比无盐处理Ⅰ(0mmol NaCl)的减小了30%左右;当土壤含盐量达到27.95g.kg-1(200mmol NaCl)时,该处理幼苗的生物量比无盐处理Ⅰ的减小了80%左右,幼苗难以正常生长。②盐分对胡杨幼苗的光合速率和水分利用效率影响显著。随着盐浓度增大,胡杨幼苗的净光合速率下降。当土壤含盐量小于18.32g.kg-1时,胡杨幼苗可以通过降低蒸腾速率,提高自身的水分利用效率和耐盐性;当土壤含盐量大于18.32g.kg-1时,胡杨幼苗的水分利用效率降低,幼苗生长表现出盐害症状。③随着盐浓度增大,盐分对胡杨幼苗的荧光特性影响明显,最大光化学效率(Fv/Fm)、PSⅡ的有效光化学量子效率(Fv′/Fm′)、光化学淬灭系数(qP)、电子传递速率(ETR)显著减小,非光化学淬灭系数(NPQ)呈增大趋势。
Based on the control experiment, the effects of salinity on the growth and photosynthetic characteristics of Populus euphratica seedlings were studied. The results showed that with the increase of salt concentration, the salinity significantly affected the plant height, base diameter and biomass of Populus euphratica, and the extent was leaf> root> stem. When soil salinity was less than 18.32g.kg-1 (50mmol NaCl), the biomass of seedlings decreased by 30% compared with that of salt-free treatment Ⅰ (0mmol NaCl). When soil salt content reached 27.95g.kg- 1 (200 mmol NaCl), the biomass of seedlings decreased by about 80% compared with that of salt-free treatment Ⅰ, and the seedlings were difficult to grow normally. ② Salt had a significant effect on photosynthetic rate and water use efficiency of Populus euphratica seedlings. With the increase of salt concentration, the net photosynthetic rate of Populus euphratica seedlings decreased. When soil salinity was less than 18.32g.kg-1, Populus euphratica seedlings could improve their water use efficiency and salt tolerance by reducing transpiration rate. When soil salt content was more than 18.32g.kg-1, Water use efficiency decreased, seedling growth showed salt damage symptoms. (3) With the increase of salt concentration, the effects of salinity on the fluorescence characteristics of Populus euphratica seedlings were obvious. The maximum photochemical efficiency (Fv / Fm), the effective photochemical quantum efficiency (Fv ’/ Fm’), the photochemical quenching coefficient (qP) Transfer rate (ETR) was significantly reduced, non-photochemical quenching coefficient (NPQ) showed an upward trend.