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热带雨林下砂仁叶片光合作用和叶绿素荧光参数在雾凉季和雨季的日变化 被引量:36

Diurnal changes in photosynthesis and chlorophyll fluorescence parameters of Amomum villosum lour. grown under tropical rainforest in rainy, and foggy and cool seasons at Xishuangbanna
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摘要 于雾凉季和雨季研究了自然条件下透光率不同的 3块雨林样地下砂仁叶片光合参数和叶绿素荧光参数的日变化。结果表明 :(1 )砂仁叶片净光合速率 (Pn)与叶表光量子通量密度 (PFD)和气孔导度 (Gs)呈正相关 ,与胞间 CO2 浓度呈负相关 ,PFD是影响 Pn 的主导因素。雾凉季砂仁叶片 Pn 和 Gs及其日变幅均低于雨季 ,相同光强下雾凉季 Pn及表观光能和 CO2 利用效率也低于雨季 ,这与雾凉季的光强和温度较低有关。 (2 )随日间光强的增加光系统 最大光能转换效率 (Fv/ Fm)、光系统 光能捕获效率 (Fv′/ Fm′)和电子传递量子效率 (ΦPS )下降 ,非光化学猝灭系数 (N PQ)和电子传递速率则上升 ,黄昏各参数都能恢复到黎明时的水平。表明随光强的增加 ,砂仁热耗散增多 ,日间光抑制加重 ,这种光抑制是光合功能下调的保护性反应而非光破坏。(3) Fv/ Fm、Fv′/ Fm′和ΦPS 与 PFD呈负相关 ,N PQ与 PFD呈正相关。相同光强下雾凉季 Fv/ Fm、Fv′/ Fm′和ΦPS 低于、N PQ则高于雨季 ,这与雾凉季 Pn 较低有关。 (4 )随栽培时间的延长砂仁衰老和产量降低均不明显 ,砂仁的产量随生长环境光强的增加而呈升高趋势。各季节不同光强下生长的砂仁在午间高光强时均未发生光合机构的破坏 ,且随光强的升高其 Pn呈上升趋势 ,说明砂仁具有适? Amomum villosum Lour. (Zingeraceae) is a perennial herb that occurs in the understory of tropical and subtropical forests, and is an important medicinal plant. A. villosum, native to Guangdong province, was introduced intentionally to Xishuangbanna, Yunnan province in 1963, and was planted under tropical rainforest. Farmers often thinned out some (5%~85%) canopy trees when they grew this plant for commercial purpose in the primary forests. Consequently biodiversity of these forests decreased, and A. villosum fruit yield was low and changed greatly among fields and years due to the crude cultivation method. To improve its yield and to protect rainforest biodiversity we should know the light regimes that are suitable to A. villosum growth. Furthermore, we want to know how A. villosum acclimates to high light environment. In this study the diurnal and seasonal changes of photosynthesis and chlorophyll fluorescence parameters were studied in A. villosum grown under three experimental fields of tropical rainforest with different light regimes (41.8%, 28.8% and 53.3% sunlight, respectively). The results showed that (1) in foggy and cool season most of single leaf net photosynthetic rate (P n) diurnal changes exhibited mono-peak pattern, while in the rainy season most of them showed two-peak pattern with an obvious midday depression. The P n, stomatal conductance (G s), and their diurnal change extent were smaller in foggy and cool season than those in rainy season, which might be associated with low light and temperature in foggy and cool season. (2) P n was correlated with photon flux density (PFD) and G s significantly positively, but with intercellular CO 2 concentration negatively. While PFD was the dominant influencing factor of P n. P n, apparent light use efficiency and apparent CO 2 use efficiency of A. villosum were lower in foggy and cool season than those in rainy season. (3) With the diurnal light increase, photoinhibition of photosynthesis was intensified in A. villosum as indicated by the decrease of maximum efficiency of PSⅡ photochemistry ((F v/F m),) the excitation capture efficiency of PSⅡ (F v′/F m′ ), and quantum efficiency of PSⅡ(Φ (PSⅡ)), whereas thermal dissipation increased as indicated by the increase of non-photochemical quenching (NPQ). This kind of photoinhibition did not result from photodamage, but was photoprotective reaction due to the down-regulation of photosynthetic function, because F v/F m, (F v′/F m′) and Φ (PSⅡ) at dusk could be recovered to the levels at predawn. The diurnal change extent of chlorophyll fluorescence parameters were smaller in foggy and cool season than those in rainy season. (4) F v/F m, F v′/F m′ and Φ (PSⅡ) were correlated with light intensity negatively, whereas NPQ was correlated with light intensity positively. At the same light intensity F v/F m, F v′/F m′ and Φ (PSⅡ) were lower, whereas NPQ was higher in foggy and cool season than those in rainy season, which was associated with low P n in foggy and cool season. (5) With the time increase of planting A. villosum, plant senescence, as indicated by the decrease of leaf chlorophyll content, was not always intensified, and fruit yield was not always decreased. The output of (A. villosum) increased with the light intensity of experimental field. Photodamage of photosynthetic apparatus was not found in (A. villosum) under different light regimes in this study. In addition, P n increased with light intensity. All the results presented above indicated that A. villosum had potential capacity to grow and acquire high yield under higher light environment.
出处 《生态学报》 CAS CSCD 北大核心 2004年第7期1421-1429,共9页 Acta Ecologica Sinica
基金 中国科学院"西部之光"人才培养计划资助项目 中国科学院知识创新工程重大资助项目 ( KSCX1-SW-13 -0 X-0 X)~~
关键词 光合作用 叶绿素荧光 日变化 季节变化 产量 砂仁 photosynthesis chlorophyll fluorescence diurnal changes, seasonal changes yield, Amomum villosum Lour.
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