| 杉木中龄林针叶光合作用对光斑的响应 |
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| 引用本文： | 张小全,徐德应.杉木中龄林针叶光合作用对光斑的响应[J].植物生态学报,2000,24(5):534-540. |
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| 作者姓名： | 张小全 徐德应 |
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| 作者单位： | 中国林业科学院研究院森林生态环境与保护研究所,北京 |
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| 基金项目： | 国家自然科学基金资助项目“杉木人工林光合作用尺度转换研究”!（编号：39770596），国家林业局森林生态环境重点实验室资助课 |
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| 摘 要： | 对18年生杉木(Cunninghamia lanceolata(Lamb．)Hook．)当年生针叶净光合速率(Pn)对不同时间和强度的猝发性辐射和模拟光斑响应的研究表明：经长时间低光或暗处理后针叶的Pn对猝发性连续强光的响应呈S形曲线，约需10～15min的光诱导才能达到相应光强下的最大值；猝发性辐射强度越大，所需光诱导时间越长；低光期越长，低光期辐射越小，所需光诱导期越长；但只要光斑间隔不是太长，针叶仍可保持原有的光诱导状态。针叶Pn对单个瞬时光斑的响应与光斑前的光诱导状态和光斑时间长短有关，充分诱导的针叶Pn对光斑的响应较未诱导或未充分诱导的针叶要灵敏得多，光斑时间延长可提高光诱导状态，从而提高Pn。光斑消失后Pn缓慢下降表明针叶对光斑的响应存在明显的光后CO2固定，在瞬时光斑较多的林内，光后CO2固定可占总同化量的相当大比例。
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| 关 键 词： | 杉木针叶 净光合速率 光斑 |
RESPONSE OF NET PHOTOSYNTHETIC RATE IN 18-YEAR-OLD CHINA FIR SHOOTS TO LIGHTFLECKS |
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| ZHANG Xiao-Quan,XU De-Ying.RESPONSE OF NET PHOTOSYNTHETIC RATE IN 18-YEAR-OLD CHINA FIR SHOOTS TO LIGHTFLECKS[J].Acta Phytoecologica Sinica,2000,24(5):534-540. |
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| Authors: | ZHANG Xiao-Quan XU De-Ying |
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| Abstract: | The response of net photosynthetic rate (Pn) in new growth shoots of 18-year-old China fir (Cunninghami- a lanceolata (Lamb. )Hook. ) to sudden exposure to high-light and lightflecks was measured and is discussed in this paper. Pn showed a S-shape response to sudden exposure following a period of low-light or darkness adaptation, and 10-15 minutes of photo induction was required for Pn to attain its maximum level. With increasing intensity of the high-light exposure a longer induction period was required. Longer exposure and /or lower levels of low-light also increased the induction period. Following the passage of the initial light fleck shoots showed a hysteretic response by maintaining an induction state during non-consecutive light-flecks unless light-leeks were separated by a long period of low light. The response of Pn to instantaneous light-flecks depended on induction status and light-fleck duration; fully inducted shoots could respond, more rapidly than low or non-inducted shoots; the raised photo induction associated with light-flecks of longer length could thus contribute to increased Pn. The slow decrease of Pn after light-flecks suggested that there existed postillumination CO2 fixation, and that in canopies with frequent instantaneous light-flecks, a great proportion of assimilation might be the result of postillumination CO2 fixation. |
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| Keywords: | China fir Net photosynthetic rate Light-fleck |
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