钙素对彩叶玉簪光合作用和保护酶活性的影响

该文以彩叶玉簪为材料,研究了不同钙素水平对玉簪叶片光合作用和保护酶活性的影响。结果表明:随着钙素水平的提高,彩叶玉簪叶片的净光合速率(Pn)、气孔导度(Gs)、胞间CO_2浓度(Ci)、蒸腾速率(Tr)和最大光化学效率(F_v/F_m)均呈单峰曲线,最高峰值出现在Ca~(2+)90 mg·L~(-1)时;电子传递速率(ETR)的变化也呈单峰曲线,峰值出现在Ca~(2+)50 mg·L~(-1)时;初始荧光(F_0)和最大荧光(F_m)值在0~360 mg·L~(-1)钙素水平下呈先升高后下降再升高的趋势,最大值均出现在90 mg·L~(-1)时;Pn和Gs值的变化与Ci值成正相关。同时叶片中过氧化物酶(POD)、过氧化氢酶(CAT)的活性及丙二醛(MDA)、可溶性蛋白质(SP)含量均表现为单谷曲线,在Ca~(2+)90 mg·L~(-1)时达最小值。超氧化物歧化酶(SOD)活性呈现持续下降趋势。综上所述,彩叶玉簪Pn下降主要由气孔引起,叶面喷施90 mg·L~(-1)的Ca~(2+)可增强彩叶玉簪光合作用,降低保护酶活性。

Effects of different calcium levels on photosynthesis and protective enzyme activities of colorful Hosta

The effects of different calcium levels on photosynthesis and protective enzyme activities of Hosta leaves were studied by using colorful Hosta as test materials. The results showed that the net photosynthetic rate(Pn), stomatal conductance(Gs), Intercellular CO₂ concentration(Ci), transpiration rate(Tr)and the maximum photochemical efficiency(F_v/F_m)of the colorful Hosta leaves all showed a single peak curve with the increasing of calcium levels, and the highest peak level was 90 mg·L^-1 Ca²⁺. While the apparent electron transport rate(ETR)also changed as a single peak curve and the peak was 50 mg·L^-1 Ca²⁺. The initial fluorescence(F0)and maximum fluorescence(F_m) first increased and then decreased, finally increased in calcium levels of 0-360 mg·L^-1, and 90 mg·L^-1 Ca²⁺ was the highest. The change of Pn and Gs were positively correlated with Ci. Meanwhile, the activities of peroxidase(POD)and catalase(CAT)and the contents of MAD and soluble protein(SP)of leaves all showed a single valley curve and the minimum was 90 mg·L^-1 Ca²⁺, while the activity of superoxide dismutase(SOD)had declined steadily. The results obtained from above showed that the decrease of Pn of colorful Hosta mainly resulted from the stomatal factors. The best spraying concentration of calcium was 90 mg·L^-1 which could enhance photosynthesis and reduce protective enzyme activities.