水杨酸处理对金钱草光合特性研究

以金钱草为试验材料,分别用0、0.5、2.0、5.0 mmol/L浓度的水杨酸处理后,对其光合速率、光合响应曲线、CO2响应曲线、气孔导度参数进行了测定和分析。结果表明:在一定水杨酸浓度范围内,随着外施水杨酸浓度的增加,金钱草的Pn、Tpu、Vcmax、Gs等呈现上升趋势;Lsp逐渐提高,Lcp逐渐下降,这表明喷施5.0 mmol/L的水杨酸后,金钱草对光环境的适应性最强;金钱草的Ccp随着外施水杨酸浓度的增加呈下降趋势,其水杨酸浓度2.0～5.0 mmol/L时,CO2补偿点无明显变化趋势,且处于较低水平,表明金钱草在经过水杨酸处理后,当空气中CO2浓度较低时,金钱草便可开始进行光合作用,并对其自身有机物质进行积累,因此,水杨酸可以有效改善金钱草的光合生理特性。

Effects of Salicylic Acid Treatment on Photosynthetic Characteristics of Lysimachia christinae Hance

The plants of Lysimachia christinae Hance were treated with 0,0.5,2.0 and 5.0 mmol/L concentrations of exogenous salicylic acid,respectively,and their photosynthetic rate,photosynthesis-light response curve,CO2 response curve,stomatal conductance parameters were measured and analyzed by LI-6400XT portable photosynthesis analyzer.The results showed that Pn(photosynthetic rate),Tpu(triosephosphate utilization),Vcmax(maximum rate of carboxylation),stomatal conductance(Gs) of Lysimachia christinae increased with the increase in the concentration of exogenous salicylic acid in a certain range.Lsp(light saturation point) increased,and Lcp(light compensation point) decreased gradually,indicating that Lysimachia christinae had the most adaptable light environment after spraying 5 mmol/L of salicylic acid.Ccp(CO2 compensation point) of Lysimachia christinae decreased along with increasing concentration of exogenous salicylic acid.When the concentration of salicylic acid was 2~5 mmol/L,CO2 compensation point was at a low level,and had no obvious change trend,indicating that Lysimachia christinae could start its own photosynthesis and the accumulation of organic substances even the CO2 concentration in the air was low as a result of salicylic acid treatment.Our data proved that salicylic acid treatment could effectively improve the photosynthetic physiological characteristics of Lysimachia christinae.