Ji Wen, Hong Erman, Chen Xia, Li Zhijun, Lin Bangyu, Xia Xuanze, Li Tianyao, Song Xinzhang, Jin Songheng, Zhu Xiangtao
State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, China.
College of Jiyang, Zhejiang A&F University, Zhuji, China.
Front Plant Sci. 2022 Oct 28;13:969718. doi: 10.3389/fpls.2022.969718. eCollection 2022.
In order to investigate the causes of the differences in heat tolerance ('Lu He Hong' and 'Zhi Hong'), we studied the physiological changes, photosynthetic properties and regulatory mechanism of the two peony cultivars at high temperature. The results showed that the physiological changed of different peony cultivars varied significantly under high temperature stress. With the extension of high temperature stress time, MDA content of 'Lu He Hong' increased,while 'Zhi Hong' rised first and then decreased, SOD activity of 'Lu He Hong' rised first and then decreased, that of 'Zhi Hong' kept rising, POD activity of 'Lu He Hong' kept decreasing, while 'Zhi Hong' rised. The photosynthetic instrument records the change of peony photosynthesis parameters at high temperature; the chlorophyll A (Chla) fluorescence transient is recorded using the plant efficiency analyzer (PEA), analyzed according to the JIP test (O-J-I-P fluorescence transient analysis), and several parameters were derived to explain the photosynthetic efficiency difference between different peony cultivars. The tested cultivars responded differently to the survey conditions, and the PCA analysis showed that the 'Zhi Hong' was more well tolerated and showed better thermal stability of the PSII. The reduced efficiency of the 'Lu He Hong' PSII antenna leads to higher heat dissipation values to increase the light energy absorbed by unit reaction center (ABS/RC), the energy captured by unit reaction center (TR/RC), and the energy dissipated by unit reaction center (DI/RC), which significantly leads to its lower total photosynthetic performance (PI). The light capture complex of the variety 'Zhi Hong' has high connectivity with its reaction center, less damage to OEC activity, and better stability of the PSII system. The results show that 'Zhi Hong' improves heat resistance by stabilizing the cell membrane, a strong antioxidant system, as well as a more stable photosynthetic system. The results of this study provide a theoretical basis for the screening of heat-resistant peonies suitable for cultivation in Jiangnan area and for the selection and breeding of heat-resistant cultivars.
为探究耐热性不同的牡丹品种（‘鲁荷红’和‘脂红’）产生差异的原因，我们研究了这两个牡丹品种在高温下的生理变化、光合特性及调控机制。结果表明，不同牡丹品种在高温胁迫下生理变化差异显著。随着高温胁迫时间的延长，‘鲁荷红’的丙二醛（MDA）含量增加，而‘脂红’先升高后降低；‘鲁荷红’的超氧化物歧化酶（SOD）活性先升高后降低，‘脂红’的SOD活性持续升高；‘鲁荷红’的过氧化物酶（POD）活性持续降低，‘脂红’的POD活性升高。光合仪记录了牡丹在高温下光合作用参数的变化；使用植物效率分析仪（PEA）记录叶绿素A（Chla）荧光瞬变，并根据JIP测试（O-J-I-P荧光瞬变分析）进行分析，得出几个参数来解释不同牡丹品种间的光合效率差异。受试品种对测试条件反应不同，主成分分析（PCA）表明，‘脂红’耐受性更强，其光系统II（PSII）表现出更好的热稳定性。‘鲁荷红’PSII天线效率降低导致更高的热耗散值，从而增加单位反应中心吸收的光能（ABS/RC）、单位反应中心捕获的能量（TR/RC）和单位反应中心耗散的能量（DI/RC），这显著导致其较低的总光合性能（PI）。‘脂红’品种的光捕获复合体与其反应中心具有高度连接性，对放氧复合体（OEC）活性损伤较小，PSII系统稳定性更好。结果表明，‘脂红’通过稳定细胞膜、强大的抗氧化系统以及更稳定的光合系统来提高耐热性。本研究结果为筛选适合江南地区栽培的耐热牡丹以及耐热品种的选育提供了理论依据。
