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林业科学 ›› 2019, Vol. 55 ›› Issue (6): 13-21.doi: 10.11707/j.1001-7488.20190602

• 论文与研究报告 • 上一篇    下一篇

日本落叶松冠层光合特性的空间变化

夏国威, 孙晓梅, 陈东升, 张守攻   

  1. 林木遗传育种国家重点实验室 国家林业和草原局林木培育重点实验室 中国林业科学研究院林业研究所 北京 100091
  • 收稿日期:2017-04-10 修回日期:2019-03-05 出版日期:2019-06-25 发布日期:2019-07-11
  • 基金资助:
    国家自然科学基金重点项目(31430017)。

Spatial Variation of Photosynthetic Characteristics in Canopy of Larix kaempferi

Xia Guowei, Sun Xiaomei, Chen Dongsheng, Zhang Shougong   

  1. State Key Laboratory of Tree Genetics and Breeding Key Laboratory of Tree Breeding and Cultivation of National Forestry and Grassland Administration Research Institute of Forestry, CAF Beijing 100091
  • Received:2017-04-10 Revised:2019-03-05 Online:2019-06-25 Published:2019-07-11

摘要: [目的]研究日本落叶松冠层间光合特性的差异,揭示冠层光合特性的空间变化规律,为精确估算冠层生产力及构建冠层生产力模型提供依据。[方法]以8年生日本落叶松为研究材料,根据树冠长度,将树冠等分为8个层级,从上到下分别为第1~8层级,选择每一层级的南向一级侧枝作为光合测定枝条,测定每一枝条上针叶的光合日变化。[结果]多数冠层间光合参数日变化规律相似,净光合速率、蒸腾速率、气孔限制值、光合有效辐射、气温和水汽压亏缺均表现为单峰曲线,气孔导度从上午开始逐渐降低。随着冠层的升高,光合参数增加、比叶面积减小,而气温和水汽压亏缺表现为先增后降的趋势,不同冠层间均差异显著(P<0.05)。净光合速率、光合有效辐射、气孔导度和蒸腾速率与相对冠高存在指数函数关系(R2 ≥ 0.94),气温和水汽压亏缺与相对冠高存在一元二次函数关系(R2 ≥ 0.79)。通径分析表明,影响净光合速率的主要因素是光合有效辐射,而气温和空气相对湿度影响较小。[结论]光合有效辐射和叶肉细胞的光合活性分别是影响日本落叶松净光合速率空间变化的主要环境因素和生理因素。净光合速率随冠层的升高而显著增加,而冠层底部净光合速率为负值,始终处于碳消耗状态。

关键词: 日本落叶松, 光合特性, 冠层, 空间变化, 通径分析

Abstract: [Objective] [Objective]To better understand the spatial heterogeneity of photosynthetic characteristics in canopy of Larix kaempferi, photosynthetic parameters of needles were measured in different canopy layers. This study could provide a sound theoretical foundation for developing a canopy productivity model and accurately evaluating canopy productivity.[Method] The 8-year-old L. kaempferi was selected as the research material, and the canopy was divided equally into 8 canopy layers according to the canopy length from top to bottom. In each tree, only one south-oriented branch was selected in each layer, and the diurnal change of photosynthesis of needles was measured on each selected branch.[Result] The diurnal change of photosynthetic parameters in most canopy layers was similar. Net photosynthetic rate (Pn), transpiration rate (Tr), value of stomatal limitation (Ls), photosynthetically active radiation (PAR), air temperature (Ta) and vapor pressure deficit (VPD) showed a single peak curve, and the stomatal conductance (Gs) gradually decreased from morning. With the increase of canopy, photosynthetic parameters increased, and specific leaf area reduced, while Ta and VPD increased firstly, and then decreased from high to low position of the canopies. There were significant significant differences (P<0.05) in the photosynthetic parameters and the micro-environmental factors among different canopy layers. The Pn, PAR, Gs, and (Tr) had exponential function relationships with relative canopy height (R2 ≥ 0.94), and the Ta and VPD had quadratic function relationships with relative canopy height (R2 ≥ 0.79). The result of path analysis showed that PAR was a main factor influencing Pn, but the impact of Ta and air humidity was relatively limited.[Conclusion] Photosynthetic effective radiation and photosynthetic activity of mesophyll cells were the main environmental and physiological factors affecting the spatial variation of Pn in L. kaempferi canopy. Pn increased significantly with the increasing canopy, while Pn at the bottom of L. kaempferi canopy was negative, indicating that the part of canopy remained in the state of carbon consumption. Therefore, we suggest that the results can be used as the important indicator for artificial pruning of L. kaempferi larch, and also can be used as the important theoretical basis for developing canopy productivity model and estimating canopy productivity.

Key words: Larix kaempferi, photosynthetic characteristics, canopy, spatial variation, path analysis

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