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林业科学 ›› 2023, Vol. 59 ›› Issue (3): 104-114.doi: 10.11707/j.1001-7488.LYKX20210944

• 研究论文 • 上一篇    下一篇

水分条件和热浪频次对木荷苗木光合特性与生长速率的影响

刘南1(),曲鲁平1,*,汤行昊2,余海霞1,张子雷1,王浩1,邵长亮3,董刚4   

  1. 1. 福建农林大学林学院 福州 350002
    2. 福建省林业科学研究院 福州 350012
    3. 中国农业科学院农业资源与农业区划研究所 北京 100081
    4. 山西大学生命科学学院 太原 030006
  • 收稿日期:2021-12-26 出版日期:2023-03-25 发布日期:2023-05-27
  • 通讯作者: 曲鲁平 E-mail:1200431006@fafu.edu.cn
  • 基金资助:
    国家自然科学基金项目(32171749,31800512,31870466);福建省林木种苗科技攻关第六期项目“木荷育种种质创新与种子园高产技术研究”(fjzmgg201904)

Effects of Water Conditions and Heat Wave Frequency on the Photosynthetic Characteristics and Growth Rate of Schima superba Seedlings

Nan Liu1(),Luping Qu1,*,Xinghao Tang2,Haixia Yu1,Zilei Zhang1,Hao Wang1,Changliang Shao3,Gang Dong4   

  1. 1. College of Forestry, Fujian Agricultural and Forestry University Fuzhou 350002
    2. Fujian Academy of Forestry Fuzhou 350002
    3. Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences Beijing 100081
    4. College of Life Science, Shanxi University Taiyuan 030006
  • Received:2021-12-26 Online:2023-03-25 Published:2023-05-27
  • Contact: Luping Qu E-mail:1200431006@fafu.edu.cn

摘要:

目的: 探究木荷苗木光合特性与生长速率在控水和补水条件下对热浪频次的响应,为揭示木荷对极端高温事件的适应机制提供理论依据。方法: 以亚热带主要阔叶树种木荷苗木为试验材料,通过人工热浪模拟装置模拟自然热浪发生,构建控水和补水与不同热浪频次(无热浪、单次热浪、2次热浪)处理,分析木荷光合特性与生长速率在控水和补水条件下对不同频次热浪胁迫的抗性和恢复能力的差异。结果: 1) 补水条件下,单次热浪对木荷光合特性影响较弱,木荷可通过增加蒸腾速率(Tr)降低叶片温度,水分利用效率(WUE)显著降低,净光合速率(Pn)未出现显著变化;2) 控水条件下,单次热浪使木荷Pn在热浪阶段显著下降49%,未见Tr和WUE显著变化,但显著减缓热浪后木荷光合特性恢复过程;3) 2次热浪频次下,无论控水还是补水条件,木荷Pn在热浪阶段均显著下降(约46%和32%),虽然热浪后可恢复,但恢复过程受阻;多次热浪的影响存在累加效应,木荷对热浪胁迫的抗性和恢复能力减弱。结论: 控水和补水条件下,木荷光合特性与生长速率对不同频次热浪胁迫的抗性和恢复能力存在差异。补水条件下,木荷可通过生理调节机制保持较好的高温抗性,但该机制在控水条件下未发挥功效。高温与干旱复合胁迫显著影响木荷光合特性与生长速率,复合胁迫的影响强度超过单一因素影响的简单叠加。亚热带地区季节性高温与干旱复合胁迫或高频连续热浪的发生,可能显著改变木荷林的结构和功能,影响生态系统的稳定性和可持续性。

关键词: 极端气候, 控水, 补水, 净光合速率, 抗性, 恢复力, 热浪

Abstract:

Objective: This study aims to investigate the effect of different heat wave frequencies and contrasting water additions on the photosynthetic characteristics and growth ofSchima superba seedlings, so as to provide theoretical basis for revealing its adaptation mechanism to extreme high temperature events. Method: In this study, S. superba seedlings, a common broad-leaved tree species, were chosen as the experimental materials. An artificial heat wave simulation device was used to simulate the occurrence of natural heat waves. The seedlings were subjected to water control and replenishment treatments with different heat wave frequencies (no heat wave, single heat wave, two heat waves). The differences in the photosynthetic characteristics and growth rate of S. superba seedlings were analyzed for their resistance and resilience ability to different frequency of heat wave stress. Result: 1) With water addition, the single heat wave treatment had insignificant effects on the photosynthetic characteristics. S. superba was able to regulate leaf temperature by significantly increasing its transpiration rate (Tr), thus reducing water use efficiency (WUE) significantly, but there was no significant change in net photosynthetic rate (Pn). 2) Under controlled water supply condition, a single heat wave significantly decreased S. superba Pn by 49%, while there were no significant changes in Tr and WUE. However, the treatments significantly slowed down the recovery process of photosynthetic characteristics of S. superba. 3) Under the influence of two heat waves, regardless of water control and replenishment conditions, S. superba Pn significantly decreased (about 46% and 32%) during heat wave stage, respectively. Although it was able to still recover after the heat wave, the recovery process was hindered. The effects of multiple heat waves were additive, manifested as a weakening of the resistance and recovery ability of S. superba to heat waves. Conclusion: Our results indicate that the photosynthetic characteristics and growth rates of S. superba demonstrate divergent resistance and resilience to heat waves with the different water supply. The seedlings can maintain high temperature resistance through physiological regulation mechanism, but this mechanism would be disturbed when water supply is not adequate. Moreover, the interaction of high temperature and drought significantly affect the photosynthetic characteristics and growth rate of S. superba, and the effects of compound stress are stronger than single factor effects. These results suggest that the occurrence of combined seasonal high temperature and drought stress in subtropical regions, or the occurrence of high-frequency successive heat waves may significantly change the structure and function ofS. superba natural forests and plantations, as well as its stability and sustainability.

Key words: climate extremes, water supply, drought, net photosynthetic rate, resistance, recovery, heat wave

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