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为探讨钙(Ca2+)对甜椒幼苗生长的影响,以甜椒品系156为试材,分别喷施清水(对照)、5 mmol·L-1(T5)和10 mmol·L-1Ca Cl2(T10),研究了高温(37℃)强光(1 200μmol·m-2·s-1)胁迫下甜椒幼苗叶片光合作用及叶片中活性氧(ROS)清除酶活性的变化。结果表明,高温强光胁迫条件下,与对照植株相比,外源施钙可维持较高的净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)及较低的胞间CO2浓度(Ci)。甜椒幼苗功能叶在高温强光胁迫处理后,T5和T10叶片的1,5-二磷酸核酮糖羧化酶(Rubisco)活性及叶片PSII最大光化学效率(Fv/Fm)较高,表明Ca2+有利于减轻胁迫条件下甜椒幼苗叶片的光抑制现象。另外,高温强光胁迫条件下,植株叶片活性氧清除酶活性和可溶性蛋白含量明显增加,且Ca2+处理(T5和T10)的植株高于对照植株,丙二醛(MDA)含量和相对电导率则明显低于对照,这些结果均表明胁迫条件下外源施钙可以通过提高幼苗叶片ROS清除酶活性和渗透调节物质含量来保护光系统反应中心,从而减轻外界胁迫对植物的伤害。
In order to investigate the effect of calcium (Ca2 +) on the growth of sweet pepper seedlings, the sweet pepper variety 156 was sprayed with water (control), 5 mmol·L-1 (T5) and 10 mmol·L-1 CaCl2 ) Were used to study the photosynthesis and the activity of reactive oxygen species (ROS) scavenging enzymes in leaves of sweet pepper seedlings under the stress of high temperature (37 ℃) (1 200μmol · m-2 · s-1). The results showed that under high temperature and high light stress, compared with the control plants, the external application of calcium could maintain a higher net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr) and lower intercellular CO2 concentration (Ci). After treatment with high temperature and light stress, the activities of Rubisco and the maximum PSII photochemical efficiency (Fv / Fm) of leaves in T5 and T10 leaves were higher, indicating that Ca2 + It is helpful to reduce the photoinhibition of sweet pepper seedling leaves under stress. In addition, under high temperature and high light stress, the activities of active oxygen scavenger and soluble protein in leaves of plants increased significantly, and the plants treated with Ca2 + (T5 and T10) were higher than those of the control plants. The contents of MDA and relative conductivity These results indicate that the exogenous calcium application under stress can protect the photosystem reaction center by increasing ROS scavenging enzyme activity and osmotic adjustment substance content in seedling leaves, so as to reduce the damage to plants caused by external stresses.