NaCl胁迫对喜树幼苗生长和光合特性的影响

Effects of NaCl stress on seedlings growth and photosynthesis characteristics of Camptotheca acuminata

以1年生喜树幼苗为材料,研究在不同NaCl浓度胁迫下喜树幼苗的生长和光合特性。结果表明,随着NaCl浓度的升高,幼苗植株的相对生长量明显降低,盐害指数升高,叶片细胞膜相对透性显著增加;NaCl浓度≤0.30%时,幼苗叶片叶绿素a、叶绿素b含量比对照均有不同程度的增加,而在NaCl浓度≥0.45%时与对照无差异;净光合速率、蒸腾速率、气孔导度、胞间CO2浓度均降低,而气孔限制因素是盐胁迫导致喜树幼苗光合作用下降的主要原因。

Effects of NaCl stress with the different concentrations on photosynthesis characteristics and the growth of 1-year-old Camptotheca acuminata seedlings were studied. The results showed that the relative growth increments of seedlings decreased obviously with the increase of salt concentrations, while the salt injury index and the relative membrane permeability increased sig- nificantly. The contents of chlorophyll a （ ch.1 a） and chlorophyll b （ eh.1 b） in leaves of C. acuminata seedlings increased in comparison with the contrast when the concentration of NaCl was lower than 0.30% and the content of ch.1 a and ch.1 b had no difference with the contrast when the concentration of NaCl was higher than 0.45%. The net photosynthetic rate, stomatal conductance and transpiration rate declined with the increase of NaCl concentrations and the primary reason of the decrease of photosynthesis rate was stomatic factor under salt stress.