外源一氧化碳供体高铁血红蛋白对盐胁迫下黄连幼苗光合参数及叶绿素荧光特性的影响

目的通过外源物质对黄连幼苗进行处理,研究黄连幼苗光合特性及叶绿素荧光特性的变化,寻找提高黄连幼苗在盐胁迫条件下抗性能力的途径。方法测定100 mmol/L的Na Cl模拟盐胁迫条件下,经过不同浓度的外源一氧化碳(CO)供体高铁血红蛋白(hematin,H)处理后,黄连幼苗光合色素量、叶绿素荧光参数及气体交换参数等光合生理指标的变化。结果 Na Cl胁迫下的黄连幼苗的光合生理受到显著抑制,但是经过不同浓度的H处理后,显著提高了叶绿素a(Chl a)、叶绿素b(Chl b)、Chl(a+b)和类胡萝卜素等光合色素的量。盐胁迫下,黄连植株的净光合速率(Pn)、气孔导度(Gs)及叶片蒸腾速率(Tr)均下降,并且随着胁迫时间和胁迫浓度的增加,下降幅度逐渐增大,胞间CO2浓度(Ci)则呈上升趋势。在盐胁迫下,黄连Pn降低的主要影响因素是非气孔因素。在应用H进行处理后,黄连的Pn、Gs及Tr均有不同程度地提高,Ci也有不同程度的降低,并且不同的浓度梯度存在着显著的效果差异。H处理还提高了最大荧光(Fm),最大光化学效率(Fv/Fm),光系统II(PSII)潜在活性(Fv/Fo),PSII有效光化学效率(Fv′/Fm′),PSII实际光化学效率(ΦPSII),光化学淬灭系数(q P),电子传递率(ETR)和光化学速率(PCR)的水平,有效地降低了初始荧光(Fo),非光化学淬灭系数(NPQ)和热耗散速率(HDR)的水平。结论外源CO供体H通过提高黄连幼苗叶片的光合色素量,减少过剩激发能的耗散,提高光合电子传递效率,有效地缓解盐胁迫对黄连叶片PSII的伤害,提高植株的抗盐能力。

Effect of exogenous carbon monoxide donor Hematin on photosynthesis parameters and chlorophyll fluorescence characteristics of Coptis chinensis seedlings under NaCl stress

Using exogenous carbon monoxide (CO) donor Hematin (H) to study the changes of photosynthesis parameters and chlorophyll fluorescence characteristics in Coptis chinensis seedlings under NaCl stress and get the way for promoting the resistance ability of C. chinensis seedlings under NaCl stress. Methods Under 100 mmol/L NaCl stress, the several physiological indexes of C. chinensis seedlings treated by H at the different concentration, such as the contents of photosynthetic pigment and the parameters of chlorophyll fluorescence and photosynthesis, were measured. Results Under NaCl stress the photosynthetic physiology of C. chinensis seedlings was inhibited, but the contents of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids could be obviously increased after the treatment of H at different concentration. The levels of the net photosynthetic rate (P_n), stomatal conductance (G_s), and transpiration rate (T_r) in C. chinensis seedlings were all decreased, which would gradually increase with the time and concentration increase of NaCl stress, while the concentration of CO₂ (C_i) increased with the opposite tendency. These results indicated that the main influencing factor of decreasing P_n of C. chinensis was non-stomatal factors. After being treated with different exogenous substances, the P_n, G_s, and T_r were all increased in different degrees, but the level of C_i was decreased. And the maximum fluorescence (Fm), photochemical efficiency of photosystem II (Fv/Fm), potential photochemical efficiency (Fv/Fo), photochemical efficiency (Fv'/Fm'), PSII actual photochemical efficiency (ΦPSII), photochemical quenching coefficient (qP), electronic transfer rate (ETR), and photochemistry rate (PCR) were obviously increased, while the levels of minimal fluorescence (Fo), non-photochemical quenching coefficient (NPQ), and heat dissipation rate (HDR) were effectively decreased. Conclusion Exogenous CO H with the appropriate concentration of 2.0 mmol/L could reduce the excess excitation dissipation, improve photochemical electron transport efficiency, and efficiently protect C. chinensis leaves from PSII damage by significantly alleviating the damages of salt stress to C. chinensis so that H could obviously promote the salt resistance to C. chinensis under salt stress.