《植物生理学报》 2015, 51(3): 280-286

高温强光胁迫下外源钙对甜椒(Capsicum fructescens L.)幼苗光合生理特性的影响

孙克香^1,2, 杨莎², 郭峰², 刘翠敏³, 孟静静², 胡春梅^1,*, 李新国^2,*

¹南京农业大学园艺学院, 南京210095; ²山东省农业科学院生物技术研究中心,山东省作物遗传改良与生态生理重点实验室, 济南250100; ³中国科学院遗传与发育生物学研究所, 北京 100101

通信作者：胡春梅；E-mail: lixinguo@tom.com, jjjhcm@njau.edu.cn ；Tel: 0531-83179047; 025-84395756

摘　要：

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^-1 CaCl₂ (T10), 研究了高温(37 ℃)强光(1 200 μmol•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(G_s)、蒸腾速率(T_r)及较低的胞间CO₂浓度(C_i)。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(F_v/F_m)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。

关键词：钙; 高温; 强光; 甜椒; 光合作用

收稿：2014-12-18   修定：2015-01-29

资助：国家科技支撑计划(2014BAD11B04)、山东省农业重大应用技术创新课题、山东省自主创新成果转化重大专项(2012ZHZXIA0418)、山东省自然科学基金项目(ZR2011CQ042)、山东省农业科学院科技创新重点项目(2014CXZ06-6)和现代农业产业技术体系建设专项资金资助(CARS-14)。

Effects of Exogenous Calcium on Photosynthetic Chracteristics of Sweet Pepper (Capsicum fructescens L.) Seedlings

SUN Ke-Xiang^1,2, YANG Sha², GUO Feng², LIU Cui-Min³, MENG Jing-Jing², HU Chun-Mei^1,*, LI Xin-Guo^2,*

¹College of Horticulture of Nanjing Agricultural University, Nanjing 210095, China; ²Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Biotechnology Research Center, Shandong Academy of Agricultural Sciences, Jinan 250100, China; ³Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China

Corresponding author: HU Chun-Mei; E-mail: lixinguo@tom.com, jjjhcm@njau.edu.cn ; Tel: 0531-83179047; 025-84395756

Abstract:

In order to investigate the effects of calcium (Ca²⁺) on growth of sweet pepper seedlings, sweet pepper line 156 was used as materials which were cultured with water (control), 5 mmol•L^-1 (T5) and 10 mmol•L^-1 CaCl₂ (T10), respectively. In the present work, the photosynthesis and the activity of reactive oxygen species (ROS) scavenging enzymes in sweet pepper seedlings were studied. Relative to control, Ca²⁺- applied seedlings kept higher net photosynthetic rate (P_n) , higher stomatal conductance (G_s), higher transpiration rate (T_r), and lower intercellular CO₂ concentration (C_i). When functional leaves were exposed to high temperature (37 ℃) and high irradiance (1 200 μmol•m^-2•s^-1), T5 and T10 seedlings had higher ribulose-1,5-bisphosphate carboxylase/ oxygenase (Rubisco) activity and higher maximal photochemical efficiency of photosystem II (PSII) (F_v/ F_m), indicating that Ca²⁺ could help to alleviate photoinhibition of sweet pepper seedlings under stress. Additionally, the activity of ROS scavenging enzymes and the soluble protein content were higher in T5 and T10 seedling leaves than in control seedlings, simultaneously, the content of malonaldehyde (MDA) and relative electric conductivity were lower in T5 and T10 seedling leaves. These results indicated that exogenous Ca²⁺ could alleviate the damage of environmental stress to photosynthetic reaction centers of sweet pepper leaves by improving the activity of ROS scavenging enzymes and the contents of some osmoregulation substances.

Key words: calcium; high temperature; high irradiance; sweet pepper; photosynthesis