植物生态学报 ›› 2018, Vol. 42 ›› Issue (5): 585-594.DOI: 10.17521/cjpe.2018.0016

• 研究论文 • 上一篇    下一篇

橡胶林下益智光合特性的季节动态变化

程汉亭,李勤奋,刘景坤,严廷良,张俏燕,王进闯()   

  1. 中国热带农业科学院环境与植物保护研究所/农业部儋州农业环境科学观测实验站, 海口 571101
  • 收稿日期:2018-01-12 修回日期:2018-04-08 出版日期:2018-05-20 发布日期:2018-07-20
  • 通讯作者: 王进闯

Seasonal changes of photosynthetic characteristics of Alpinia oxyphylla growing under Hevea brasiliensis

CHENG Han-Ting,LI Qin-Fen,LIU Jing-Kun,YAN Ting-Liang,ZHANG Qiao-Yan,WANG Jin-Chuang()   

  1. Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences/Danzhou Scientific Observing and Experimental Station of Agro-Environment, Ministry of Agriculture of the People’s Republic of China, Haikou 571101, China
  • Received:2018-01-12 Revised:2018-04-08 Online:2018-05-20 Published:2018-07-20
  • Contact: Jin-Chuang WANG

摘要:

利用农林复合模式发展生态农业可提高资源利用效率, 橡胶(Hevea brasiliensis)-益智(Alpinia oxyphylla)间作模式是橡胶园最主要的农林复合模式。该研究通过野外原位定位实验, 研究不同季节橡胶林下环境因子对益智光合作用的影响, 并进一步分析益智光合作用与主要环境因子的关系。结果表明: (1) 3月益智净光合速率日变化为“V”形曲线, 14:00降到最低值; 而6月、9月和12月益智净光合速率日变化趋势为10:00达到最大值, 随后缓慢降低; 在雨季(6月和9月)蒸腾速率的日平均值和日最高值均显著高于旱季(3月和12月)。表明林下益智在不同季节均能维持植株正常生长, 且表现出了较强的适应能力。3月土壤水分亏缺造成益智叶片气孔导度降低, 使其净光合速率维持在较低的水平。(2)通过光响应曲线修正模型计算出益智叶片各光合响应参数, 发现3月最大净光合效率和光饱和点显著低于6月、9月和12月; 而光补偿点和暗呼吸速率却显著高于6月、9月和12月, 表明3月土壤水分亏缺导致益智光合酶活性降低, 而表现出光抑制现象, 同时呼吸强度加剧, 光合能力显著下降。(3)采取相关分析发现, 3月气温与净光合速率显著负相关, 空气湿度与净光合速率显著正相关, 高温和低湿度共同限制了益智的光合作用; 而9月和12月, 林下光合有效辐射是益智光合作用的限制因子。

关键词: 光合特性, 环境因子, 益智, 季节变化, 光合日变化

Abstract:

Aims The development of ecological agriculture by agroforestry models could improve resource utilization. The Hevea brasiliensis-Alpinia oxyphylla agroforestry system is among the largest agroforestry models in rubber plantation. In this study, we aimed to investigate the physiological strategies that allow Alpinia oxyphylla, a perennial herb widespread under-growing the Hevea brasiliensis, to cope successfully with the environmental factors with the seasonal changes of the tropical monsoon climate.

Methods Gas exchange and light response curve measurements as well as pigment content determinations were performed periodically throughout different seasons on A. oxyphylla growing in the rubber plantation by a portable leaf gas exchange system (LI-6400).

Important findings (1) The diurnal change of the net photosynthetic rate had a V-shaped pattern in March, which decreased to be the lowest at 14:00. The diurnal changes of the Pn in June, September, and December increased to the peak at 10:00 and then began to decline slowly. The daily average and maximum of the net photosynthetic rate during the monsoon season (June and September) were much higher than those in the dry season (March and December), which suggested that A. oxyphylla had the physiological strategy to environmental changes in different seasons. The severe soil moisture deficit inhibits photosynthetic CO2 assimilation due to the decline of stomatal conductance in March. (2) The light compensation point and dark respiration rate of March generally were higher than those of other seasons (June, September and December), but the maximum net photosynthetic rate and light saturation point were on the contrary. The discrepancies that may be related to the photosynthetic enzymatic activity were restrained by the dry conditions, which caused the occurrence of photoinhibition, the increased respiration, and decreased photosynthetic capacity. (3) The net photosynthetic rate in March was negatively correlated with air temperature, but positively correlated with air humidity. Air temperature and air humidity in combination inhibited photosynthesis of A. oxyphylla in March. However, photosynthetic active radiation was a pivotal factor to photosynthesis of A. oxyphylla in September and December.

Key words: photosynthetic characteristics, environmental factor, Alpinia oxyphylla, seasonal change, diurnal change of photosynthesis