Na_2CO_3和NaCl胁迫对珙桐叶片光合特性影响的比较

On Comparison of Stress from Na_2CO_3 and NaCl on Photosynthetic Characteristics of Davidia involucrata Baill

以珙桐为材料,采用Li-6400型便携式光合测定系统研究了不同浓度(0,5,10,15,20mmol/L)Na2CO3和相应浓度的NaCl胁迫处理对珙桐叶片光合特性的影响.采用Li-6400型便携式光合测定系统对光合特性相关指标进行了测量.试验结果表明:低浓度(5,10mmol/L)Na2CO3的胁迫对珙桐叶片的净光合速率有一定的促进作用,但NaCl对珙桐净光合速率的作用却呈现低浓度(5,10mmol/L)抑制而高浓度(15,20mmol/L)促进的趋势;对于胞间CO2浓度而言,两种物质虽然都有一定程度的促进作用,但随着溶液浓度的增加,其影响效果呈现出了不同趋势,其中当Na2CO3浓度为10mmol/L时对其有明显得到抑制效果;随着溶液浓度的增加,Na2CO3与NaCl对珙桐叶片气孔导度和蒸腾速率抑制效果也呈规律性增加.由此可见,随着环境条件中Na2CO3和NaCl浓度的增大,由Na2CO3等碱性盐所造成的碱胁迫对植物的破坏作用明显大于由NaCl等中性盐所造成影响.

In this paper ,photosynthetic characteristics of D . involucrate under stress from different con‐centrations （0 ,5 ,10 ,15 ,20 mmol/L） Na2 CO3 and the same concentration of NaCl have been concerned . Li‐6400 has been used to measure the photosynthesis related indicators .The results show that low concen‐tration （5mmol/L - 10mmol/L） of Na2 CO3 stress on leaf net photosynthesis plays a certain role in promo‐ting photosynthetic rate ,while NaCl is presented to promote after suppression .With the solution concen‐tration increased ,the effect of two substances shows different effect trends on intercellular CO 2 concentra‐tion .Additional ,the solution of Na2 CO3 （10 mmol/L） has obviously inhibitory effect on it .The effects on leaf stomata conductance and transpiration rate also increases with the concentration increasing of Na 2 CO3 and NaCl .Thus ,as the concentration increasing of Na2 CO3 and NaCl ,the damage caused by Na2 CO3 to the plant would be more serious than caused by NaCl .