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低温胁迫对3种常绿阔叶树种苗木光合能力的影响

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以格木(Erythrophleum fordii)、闽楠(Phoebe bournei)和樟树(Cinnamomum camphora)3种常绿阔叶树种苗木为研究对象,以日平均气温19.5℃为对照,12.0℃和7.1℃分别作为低温胁迫Ⅰ和Ⅱ处理,分析广州冬季自然降温过程中苗木气体交换参数和光响应曲线特征参数的变化.研究结果表明,与对照相比,低温胁迫后3个树种苗木净光合速率(Pn)均有不同程度下降,但格木和闽楠在低温胁迫Ⅱ阶段的Pn比低温胁迫Ⅰ阶段有所回升.气孔导度(Gs)和胞间CO2浓度(Ci)的变化表明低温胁迫Ⅰ阶段Pn下降可能是非气孔限制因素引起的,而低温胁迫Ⅱ阶段闽楠的Pn下降可能是气孔限制因素引起的,格木和樟树仍是Pn下降可能是非气孔限制因素引起的.随着低温胁迫加强,格木因蒸腾速率(Tt)升高而导致水分利用效率(WUE)逐渐下降,而闽楠和樟树的Tr逐渐降低,WUE逐渐升高.3个树种幼苗在对照时的光补偿点(LCP)均低于20 μmol· m-2·s-1,光饱和点(LSP)均高于800 μmol·m-2·s-1,对光环境的适应性较强,具有较强的光能利用能力;低温胁迫使最大光合速率(Amax)均下降、LSP降低、LCP升高,表明低温下幼苗的光能利用能力和对光环境的适应性都下降.格木暗呼吸速率(Rd)的变化趋势与LCP的相同,而樟树和闽楠Rd的变化趋势则与LCP相反,表明前者通过提高代谢来抵抗低温胁迫,其Pn的提高是以消耗更多的水分为代价的,而后两者则是通过降低代谢来适应低温,较好地协调了碳同化和水分耗散之间的关系.
The Influences of Low Temperature Stress on the Photosynthesis Capability of Three Kinds of Evergreen Tree Seedlings
The effect of low-temperature stress on photosynthetic capability of evergreen tree seedlings including Erythrophleum fordii (EF),Phoebe bournei (PB) and Cinnamomum camphora (CC) were studied.The gas exchanges parameters and the light response curve characteristic parameters of the three species in different temperatures were measured using the LI-6400 portable photosynthesis system.12.0 ℃ and 7.1 ℃ were used as low temperature stress period Ⅰ and period]Ⅱ and the control group temperature was the average daily air temperature (19.5 ℃).The results were showed as follows:low temperature stress reduced the net photosynthetic rate (Pn) of the three species,but Pn of EF and PB were higher in period Ⅱ than those in period Ⅰ.The change of stomatal conductance (Gs) and intercellular CO2 concentration (Pi) indicated that non-stomatal limitation accounted for decreasing Pn of all three species in low temperature stress period Ⅰ as well as EF and CC in cold stress period Ⅱ,while decreasing Pn of PB was due to stomatal limitation.Along with intensifying cold stress,the water uses efficiency (WUE) of EF decreased because of rising transpiration rate (Tr),CC and PB were on the contrary.For all three species,the light compensation point (LCP) were lower than 20 μmol · m-2 · s-1,and light saturation point (LSP) were higher than 800 μmol · m-2 · s-1,showing strong adaptability and utilize ability to light.Low temperature stress reduced the maximum photosynthetic rate and LSP,but increasing LCP,indicating that weakening adaptability and utilize ability to light.The changing trends of dark respiration rate (Rd) were the same with that of LCP for EF,while opposite for PB and CC,suggesting that EF resist low temperature stress by consuming more photosynthetic products and raising Pn by consuming more water,while PB and CC acclimatized themselves to cold by slow metabolism rate which well balanced carbon assimilation and water consumption.

low temperature stressgas exchange parameterscharacteristic parameters of light response curveErythrophleum fordiiPhoebe bourneiCinnamomum camphora

彭寿强、张毅龙、黄钰辉、甘先华、陈真权、彭雄俊

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云浮市林业科学和技术推广中心,广东云浮527300

广东省森林病虫害生物防治重点实验室,广东广州510520

广东省林业科学研究院,广东广州510520

云浮市林业苗圃场,广东云浮527300

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低温胁迫 气体交换参数 光响应曲线特征参数 格林 闽楠 樟树

广东省林业科技创新专项项目广东省林业科技创新专项项目广东省林业科技创新专项项目广州市科技计划项目广东森林生态环境监测及服务功能评估

2013KJCX018-032015KJCX0272015KJCX0292012Y2-00011

2016

林业与环境科学
广东省林学会,广东省林业科学研究院

林业与环境科学

影响因子：0.62
ISSN：1006-4427
年,卷(期)：2016.32(2)
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