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极小种群海南假韶子叶片光合特性和叶绿素荧光参数的动态变化

洪文君,罗金环,何书奋,麦志通,刘俊*   

  1. (三亚市林业科学研究院, 海南三亚 572000)
  • 出版日期:2020-01-10 发布日期:2020-01-10

Changes of photosynthesis characteristics and chlorophyll fluorescence of Paranephelium hainanensis,a species withextremely small population. 

HONG Wen-jun, LUO Jin-huan, HE Shu-fen, MAI Zhi-tong, LIU Jun*   

  1. (Sanya Academy of Forestry, Sanya 572000, Hainan, China)
  • Online:2020-01-10 Published:2020-01-10

摘要: 探讨海南省极小种群物种海南假韶子(Paranephelium hainanensis)的光合生理特性,以期为该物种的保护和利用提供科学依据。应用Li-COR便携式光合仪和FC1000-H便携式植物荧光成像系统测定海南假韶子的光合特性、叶绿素荧光参数的动态变化。结果表明:海南假韶子成年树和林下幼苗在7月和11月时净光合速率(Pn)和蒸腾速率(Tr)的日变化均呈明显“双峰”曲线,成年树的最大Pn达9.24 μmol·m-2·s-1,最大Tr为3.34 μmol·m-2·s-1,其光合能力显著强于幼苗;海南假韶子成年树初始荧光值(F0)在7月和11月最大值分别为323.04和135.87,Fm在7月和11月最大值分别为502.78和307.76,但幼苗的F0Fm均低于成年树;成年树Fv/Fm在7月呈单谷型,在11月时呈先降后升再降的日变化趋势;相关性分析结果表明,在7月,成年树的PnTrFv/Fm呈极显著正相关,幼苗PnF0呈极显著正相关;在11月,成年树的PnTrFm呈极显著正相关,与Fv/Fm呈显著负相关;幼苗的PnFm呈显著正相关。以上结果表明,海南假韶子为阳性树种,在7月和11月表现出不同的光合特性和叶绿素荧光参数来适应环境,水分可能是引起海南假韶子光合速率和叶绿素荧光参数动态变化的关键因子。

关键词: 黄瓜, 油菜素内酯, 低温, 光合作用, 水杨酸

Abstract: To provide scientific basis for the protection and utilization of Paranephelium hainanensis, a species with extremely small population in Hainan Province, we explored its photosynthetic physiological characteristics. The seasonal and daily dynamics of photosynthesis characteristics and chlorophyll fluorescence parameters of adult trees and understory seedlings of P. hainanensis were measured by Li-COR portable photosynthetic apparatus and FC1000-H portable plant fluorescence imaging system. The daily variation of net photosynthetic rate (Pn) and transpiration rate (Tr) of both adult trees and seedlings showed an obvious “double peak” curve in July and November. The maximum Pn and Tr of adult trees were 9.24 mol·m-2·s-1 and 3.34 mol·m-2·s-1, respectively, resulting in a stronger photosynthetic capacity than that of understory seedlings. The mean value of maximum initial fluorescence (F0) of adult trees was 323.04 and 135.87 in July and November, respectively. The average maximum fluorescence (Fm) of adult trees was 502.78 in July and 307.76 in November. Both F0 and Fm of seedlings were lower than that of adult trees. TheFv/Fm curve of adult trees showed a “singlevalley” pattern in July, and displayed a daily fluctuation with a trend of decline first, then rise and decline again in November. Results of correlation analysis showed that Pn of adult trees was positively correlated with Tr and Fv/Fm, and that Pn of seedlings was positively correlated with F0 in July. In November, Pn of adult trees was positively correlated with Tr and Fm, and negatively correlated with Fv/Fm. The Pn of seedlings was significantly positively correlated with Fm. Our results suggest that P. hainanensis is a lightdemanding tree species, with specific photosynthetic characteristics and chlorophyll fluorescence parameters in July and November to adapt to environments. Water may be the key factor causing seasonal changes of photosynthetic rate and chlorophyll fluorescence parameters inP. hainanensis.  

Key words: low temperature, salicylic acid, photosynthesis., brassinolide, cucumber (Cucumis sativa)