《植物生理学报》 2021, 57(4): 919-928

CO₂浓度与温度升高对冬小麦叶片光合与快速叶绿素荧光
特征的影响

常翠翠，张东升，郝兴宇，宗毓铮^*，高志强

山西农业大学农学院, 山西太谷030801

通信作者：宗毓铮；E-mail: zongyuzheng@163.com

摘　要：

为研究CO2浓度和温度升高对小麦叶片光系统II (PSII)性能与光合特性的影响, 以盆栽冬小麦‘郑麦9023’为材料, 通过气候变化人工模拟控制室设置不同CO2浓度(400与600 µmol·mol-1)与温度(室温与室温+2°C), 测定小麦关键生育期叶片的光合特征曲线(Pn-PAR曲线、 A-Ci曲线)与快速叶绿素荧光诱导动力学曲线(OJIP曲线), 分析光合性能的变化特征。结果表明: 增温条件下, 小麦旗叶叶绿素a、 b和类胡萝卜素浓度在开花期较对照显著增加, 但最大电子传递速率(Jmax)与最大净光合速率(Pmax)无显著变化, 最大羧化速率(Vmax)与Vmax/Jmax降低。 CO2浓度升高及其与增温的叠加作用下叶绿素浓度无显著变化, Pmax、 Jmax与Vmax较对照显著升高, 但叠加效应下Pmax与Jmax提升幅度降低。增温下小麦PSII综合性能指数(PIABS)显著受到抑制, 主要是由于PSII反应中心闭合程度(Vj)增加, 受体侧损伤, 使单位反应中心和单位横截面积电子传递能力(ETo/RC、 ETo/CSm)降低, 引起电子传递量子产额(ΨEo)减少。 CO2升高下, 虽然ETo/RC也受到抑制,但由于单位面积有活性的PSII数目(RC/CSm)增加, QA被还原速率下降, 所以PIABS得到增强。二因素叠加作用下, PSII供受体侧电子传递性能(Wk、Vj、Mo)较单一增温处理得到改善, 因而PIABS较对照没有显著降低。因此, 温度持续升高2°C可显著抑制冬小麦叶片光合系统电子传递能力, 而CO2浓度升高扩大了PSII反应中心的开放程度, 增强了供受体侧电子传递能力, 对增温产生的光合抑制具有一定的缓解作用。

关键词：冬小麦; CO2浓度升高; 增温; 光合作用; 快速叶绿素荧光

收稿：2020-09-11   修定：2021-02-01

资助：国家重点研发计划项目(2017YFD0300202-5)、山西农业大学青年拔尖创新人才支持计划(BJRC201602)、山西省青年基金 (201601D021124)和国家自然科学基金青年基金(31501276)。

Effects of elevated CO₂ concentration and increased temperature on the photosynthesis and fast chlorophyll fluorescence of winter wheat leaves

CHANG Cuicui, ZHANG Dongsheng, HAO Xingyu, ZONG Yuzheng^*, GAO Zhiqiang

College of Agriculture, Shanxi Agricultural University, Taigu, Shanxi 030801, China

Corresponding author: ZONG Yuzheng; E-mail: zongyuzheng@163.com

Abstract:

A pot experiment was conducted to examine the effects of elevated CO2 concentration ([CO2])
and increased temperature on photosynthesis and PSII performance of the leaves of winter wheat (Triticum aestivum) cv. ‘Zhengmai9023’ in controlled environment chambers. The performance of photosystem (PS)II and the electron transport were evaluated by using OJIP induction curves of chlorophyll a fluorescence, A-Ci curve and Pn-PAR curve under a full factorial combination of [CO2] [400 µmol·mol-1 (CK) or 600 µmol·mol-1 (eC)] and temperature [normal or normal+2°C (eT)]. The results showed that the eT treatment signifcantly increased the concentration of chlorophyll a, b and carotenoids, but did not affect the maximum net photosynthetic rate (Pmax) or the maximum electron transfer rate (Jmax), and decreased maximum carboxylation rate (Vmax) and Vmax/Jmax. The eC and eCeT treatments had no signifcant effect on the con centration of chlorophyll a or b, but signifcantly increased Pmax, Jmax and Vmax compared with CK. The eT treatment damaged the electron transporter on the acceptor side, increased the closure degree of PSIIcen ters (Vj), and decreased the electron transport flux from QA to plastoquinone (ETo/RC, ETo/CSm) and quan tum yield for electron transport from QA to plastoquinone (ΨEo), thereby signifcantly inhibiting the PSII per formance (PIABS). The eC treatment decreased ETo/RC, but increased the density of active PSII reaction centers (RC/CSm) and decreased the reduction of QA, thus improving the PIABS consequently. Under eCeT  treatment, the electron transport performance of PSII donor side and acceptor side were improved (Wk, Vj, Mo) compared with eT, so PIABS was unaffected compared with CK. In summary, the electron transport per formance in winter wheat leaves were signifcantly inhibited by persistent increase in temperature. This in hibition could be partially alleviated by elevated CO2 concentration.

Key words: wheat; elevated CO2 concentration; elevated temperature; photosynthesis; fast chlorophyll fluorescence