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### 长白落叶松冠层光合作用的空间异质性

1. 东北林业大学, 哈尔滨 150040
• 收稿日期:2016-04-14 发布日期:2016-09-18
• 通讯作者: * E-mail: fengrili@126.com
• 作者简介:刘 强,男,1990年生,博士研究生. 主要从事林木生长与收获模型的研究. E-mail: qiangliu2015@126.com
• 基金资助:

### Spatial heterogeneity of canopy photosynthesis for Larix olgensis.

LIU Qiang, DONG Li-hu, LI Feng-ri*, LI Xiang

1. Northeast Forestry University, Harbin 150040, China
• Received:2016-04-14 Published:2016-09-18
• Contact: * E-mail: fengrili@126.com
• Supported by:
This work was supported by the National Science & Technology Support Program (2015BAD09B01)

Abstract: Based on a 14-year-old planted Larix olgensis in the Maoershan Forest Farm, Heilongjiang Province in 2014, the spatial heterogeneity of photosynthetic indicators, environmental factors and photosynthetic physiological parameters were analyzed, meanwhile the relationship between net photosynthetic rate (Pn) and other indicators were studied. Results showed that in the vertical direction, Pn, stomatal conductance (gs) and transpiration rate (Tr) were higher in upper than middle and lower canopy significantly, intercellular CO2 concentration (Ci) increased in the sequence of upper < middle < lower canopy. Photosynthetic active radiation (PAR) decreased from outside of upper to inside of lower canopy significantly, vapor pressure deficit (VPD) and needle leaf temperature (Tl) in upper canopy were respectively higher than in middle and lower canopy significantly, while relative humidity (RH) showed no significant difference with spatial location. The mean value of maximum Pn(Pn max), dark respiration rate (Rd), light compensation point (LCP) and light sa-turation point (LSP) followed the pattern of upper > middle > lower canopy and decreased by 32.7%, 55.8%, 80.2% and 51.6% from upper to lower canopy respectively. Apparent quantum yield (AQY) in lower canopy was 1.2 and 1.3 times as much as that of middle and upper canopy, respectively. In the horizontal direction, Pn, gs, Tr, PAR and VPD were significantly higher from outside to inside in the upper crown, but Ci and RH showed no significant diffe-rence. The mean value of Pn max, Rd, LCP and LSP declined by 0.4%, 37.7%, 42.0% and 16.4% from outside to inside, on the contrary, AQY was 0.7% higher from inside to outside. Ci was the main physiological impact factor for Pn, and PAR was an important environmental factor that had the most obvious influence on Pn, especially in weak light region. Therefore, spatial heterogeneity should be considered necessarily when simulating and/or predicting the tree canopy photosynthesis.