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| 不同光强对两种桤木幼苗光合特性和抗氧化系统的影响 | |
| 引用本文： | 刘柿良,马明东,潘远智,魏刘利,何成相,杨开茂. 不同光强对两种桤木幼苗光合特性和抗氧化系统的影响[J]. 植物生态学报, 2012, 36(10): 1062-1074. DOI: 10.3724/SP.J.1258.2012.01062 |
| 作者姓名： | 刘柿良 马明东 潘远智 魏刘利 何成相 杨开茂 |
| 作者单位： | 四川农业大学风景园林学院, 成都 611130 四川农业大学林学院, 四川雅安 625014 四川省宜宾市林业科学研究院, 四川宜宾 644000 |
| 基金项目： | 四川农业大学“211双支计划”项目资助 |
| 摘 要： | 通过搭建荫棚设置3种不同的光强, 模拟森林幼苗生长的旷地(砍伐迹地)、林窗和林下光照环境(分别为100%、56.2%和12.5%的全光照), 比较研究了外来种台湾桤木(Alnus formosana)和乡土种桤木(A. cremastogyne)幼苗的叶形态、光合能力、热耗散和抗氧化酶的活性, 探讨了两树种幼苗对光强的适应及光保护策略。结果表明: 在3种光强下, 一定光强范围内随着光强的增加, 两种桤木幼苗的比叶重(LMA)、类胡萝卜素(Cars)、类胡萝卜素/叶绿素(Cars/Chl)和抗氧化酶(超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX))活性升高, 最大净光合速率(Pmax)、光饱和点(LSP)、光补偿点(LCP)和非光化学猝灭系数(NPQ)具有升高的趋势; Chl含量和瞬时光能利用效率(LUE)降低; 净光合速率(Pn)、气孔导度(Gs)、气孔限制值(Ls)升高, 胞间CO2浓度(Ci)降低, 推测Pn降低的主要因素是非气孔限制, 表明两种桤木幼苗均能适应不同的生长光强。生长在相同光强下, 桤木幼苗光抑制现象比台湾桤木幼苗严重, 台湾桤木幼苗对光强适应能力较强。随着光照强度的增加, 台湾桤木幼苗NPQ增加不显著, 热耗散较少, 相同光强下Pmax和抗氧化酶活性显著高于桤木幼苗, 而桤木幼苗随着光强的增加热耗散显著, 表明在光抑制时, 台湾桤木幼苗主要是通过提高Pmax利用光能和抗氧化酶系统进行保护性调节, 桤木幼苗则通过天线系统非辐射耗散将过剩的光能以热能的形式消耗掉。 |
| 关 键 词： | 桤木 台湾桤木 抗氧化酶 热耗散 光抑制 光适应 |
| 收稿时间： | 2012-05-28 |
| 修稿时间： | 2012-08-10 |
Effects of light regimes on photosynthetic characteristics and antioxidant system in seedlings of two alder species |
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| LIU Shi-Liang , MA Ming-Dong , PAN Yuan-Zhi , WEI Liu-Li , HE Cheng-Xiang , YANG Kai-Mao. Effects of light regimes on photosynthetic characteristics and antioxidant system in seedlings of two alder species[J]. Acta Phytoecologica Sinica, 2012, 36(10): 1062-1074. DOI: 10.3724/SP.J.1258.2012.01062 | |
| Authors: | LIU Shi-Liang MA Ming-Dong PAN Yuan-Zhi WEI Liu-Li HE Cheng-Xiang YANG Kai-Mao |
| Affiliation: | College of Landscape Architecture, Sichuan Agricultural University, Chengdu 611130, China College of Forestry, Sichuan Agricultural University, Ya’an, Sichuan 625014, China; Yibin Academy of Forestry, Yibin, Sichuan 644000, China |
| Abstract: | Aims Our objective was to investigate the effects of different light intensities on leaf morphology, photosynthetic capacity, heat dissipation and antioxidant enzyme activities in seedlings of Alnus formosana and A. cremastogyne from a hilly region near Lingyan Mountain in northwestern Sichuan Province in China. We also discuss photosynthetic acclimation and photoprotection strategies in seedlings of the two species Methods Three light regimes of 100%, 56.2% and 12.5% of natural light were simulated to match forest openings, forest gaps and forest canopies, respectively. After more than three months, we measured the parameters of gas exchange, including maximum net photosynthetic rate (Pmax), light saturation point (LSP), light compensation point (LCP), net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), intercellular CO2 concentration (Ci), fluorescent non-photochemical quenching (NPQ), maximum efficiency of PSII photochemistry (Fv/Fm) and light use efficiency (LUE), using a LI-6400 in seedling leaves. We also determined pigment contents per unit leaf area, lamina mass per unit area (LMA) and activity of antioxidant enzymes (superoxide dismutase, catalase and ascorbate peroxidase). Important findings LMA, carotenoid content (Cars), ratio of carotenoid to total chlorophyll (Car/Chl) and activities of superoxide dismutase, catalase and ascorbate peroxidase in leaves increased with the increase of light intensities. Pmax, LSP, LCP and NPQ tended to increase, while the chlorophyll content (Chl) and LUE decreased. However, the Ci decreased with the increase of Pn, Gs and stomatal limitation value (Ls). We speculated that non-stomatal limitation was the main factor that inhibited Pn. Seedlings of the two alder species could acclimate to different light regimes in this study through changing of physiological and morphological traits. Under all light regimes, diurnal photoinhibition of photosynthesis, as judged by Fv/Fm, was significantly more severe in A. cremastogyne than in A. formosana. The acclimation capacity to high light regime was stronger in A. formosana than in A. cremastogyne. With the increase of light intensities, Pmax and antioxidant enzyme activities increased significantly, but not NPQ in A. formosana. The opposite trends occurred in A. cremastogyne. At the same light intensity, thermal dissipation was much lower, but Pmax was much higher in A. formosana than in A. cremastogyne. These results indicated that A. formosana seedlings might adapt resistance to photoinhibition through improving the use of solar energy by higher Pmax and antioxidant enzyme system, while A. cremastogyne seedling avoided photoinhibition mainly through converting excess light energy to heat energy in the form of non-radiative dissipation through the antenna system. |
| Keywords: | Alnus cremastogyne A. formosana antioxidant enzyme heat dissipation photoinhibition photosynthetic acclimation |
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