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张小燕, Alison Kim Shan Wee, Tadashi Kajita, 朱俊杰, 曹坤芳. 两种红树植物不同种源幼苗对模拟高温热浪的光合生理响应差异[J]. 植物科学学报, 2021, 39(4): 424-432. DOI: 10.11913/PSJ.2095-0837.2021.40424
引用本文: 张小燕, Alison Kim Shan Wee, Tadashi Kajita, 朱俊杰, 曹坤芳. 两种红树植物不同种源幼苗对模拟高温热浪的光合生理响应差异[J]. 植物科学学报, 2021, 39(4): 424-432. DOI: 10.11913/PSJ.2095-0837.2021.40424
Zhang Xiao-Yan, Alison Kim Shan Wee, Tadashi Kajita, Zhu Jun-Jie, Cao Kun-Fang. Differences in photosynthetic responses to simulated heat wave in seedlings of two mangrove species from different provenances[J]. Plant Science Journal, 2021, 39(4): 424-432. DOI: 10.11913/PSJ.2095-0837.2021.40424
Citation: Zhang Xiao-Yan, Alison Kim Shan Wee, Tadashi Kajita, Zhu Jun-Jie, Cao Kun-Fang. Differences in photosynthetic responses to simulated heat wave in seedlings of two mangrove species from different provenances[J]. Plant Science Journal, 2021, 39(4): 424-432. DOI: 10.11913/PSJ.2095-0837.2021.40424

两种红树植物不同种源幼苗对模拟高温热浪的光合生理响应差异

Differences in photosynthetic responses to simulated heat wave in seedlings of two mangrove species from different provenances

  • 摘要: 以来自中国广西(较低纬度)和日本冲绳(较高纬度)两个地理种群的耐冷秋茄(Kandelia obovata Sheue,H.Y.Liu&J.Yong)和耐热木榄(Bruguiera gymnorrhiza (L.) Savigny)为材料,测定其光系统Ⅰ(PSⅠ)和光系统Ⅱ(PSⅡ)活性参数、叶黄素循环组分和叶绿素ab的含量,并分析他们经高温处理后光合生理响应的差异。结果显示:高温处理使植物PSⅡ最大光化学潜能(Fv/Fm)显著降低,降低幅度为较低纬度种群<较高纬度种群、木榄幼苗<秋茄幼苗;P700氧化还原状态(Pm)降低,降低幅度为较低纬度种群<较高纬度种群;叶片非光化学猝灭(NPQ)升高,表现为较低纬度种群>较高纬度种群、木榄幼苗>秋茄幼苗。高温处理引起叶黄素库容量(V+A+Z)和脱环氧化状态(A+Z)/(V+A+Z)升高,表现为较低纬度种群>较高纬度种群;(A+Z)/(V+A+Z)与Fv/Fm负相关,而与NPQ正相关。常温恢复第2 d,高纬度种源秋茄幼苗Fv/Fm仍为0.69,表明其PSⅡ受到不可逆的损伤,而其余种源幼苗的Fv/Fm均恢复到正常水平,且所有种源幼苗仍保持较高的NPQ以及叶黄素脱环氧化比率,起光保护作用。与萨瓦纳和地中海型生境相比,红树林有最大的叶黄素库。研究结果表明,低纬度种群对高温胁迫具有较高的适应性,部分原因是叶黄素循环具有较强的光保护作用,物种及种源间存在耐冷和耐热性的权衡。

     

    Abstract: We analyzed the impact of two days of high-temperature treatment on the leaf photosystem properties of potted seedlings of two mangrove species, i.e., cold-tolerant Kandelia obovata Sheue, H. Y. Liu & J. Yong and heat-tolerant Bruguiera gymnorrhiza (L.) Savigny, from two geographical populations in Guangxi, China (lower latitude) and Okinawa, Japan (higher latitude). The xanthophyll cycle components and chlorophyll-a and -b contents were measured. The leaf photosystemⅠ(PSⅠ) and photosystemⅡ(PSⅡ) activities were measured using a Dual-PAM-100 system. Results showed that high temperature significantly reduced the maximum photochemical efficiency (Fv/Fm) of PSⅡ in both species. The Fv/Fm values showed less decrease in the lower latitude populations than in the higher latitude populations, and less decrease in B. gymnorrhiza than in K. obovata seedlings. The P700 oxidation-reduction state (Pm) showed less decrease in the lower than higher latitude populations. The leaf non-photochemical quenching (NPQ) showed a greater increase in the lower latitude populations than in the higher latitude populations. The xanthophyll pool size (V + A + Z) and de-epoxidation ratio (A + Z)/(V + A + Z) increased following heat treatment. A greater increase was observed in the lower latitude populations than in the higher latitude populations. In addition, the (A + Z)/(V + A + Z) ratio was negatively correlated with Fv/Fm, but positively correlated with NPQ. Compared with other hardy habitats, such as savannas and Mediterranean woodlands, mangroves had the largest xanthophyll pool size. On the second day of recovery, Fv/Fm was still at 0.69 in the high-latitude K. obovata seedlings, indicating irreversible photoinhibition of PSⅡ, while all seedlings maintained a higher de-epoxidation ratio and NPQ for photosystem protection. In conclusion, the lower latitude populations showed higher adaptability to heat stress, which was partly due to strong photoprotection through the xanthophyll cycle, and there was a tradeoff between cold- and heat-tolerance between species and populations. This study revealed a novel heat tolerance mechanism in mangrove species, which has implications for their physiological responses to future changing climate.

     

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