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喀斯特石漠化地区不同退化程度花椒光合日动态及其与环境因子的关系

谭代军,熊康宁*,张俞,杭红涛,全明英,季传泽,马学威,张仕豪   

  1. (贵州师范大学喀斯特研究院/国家喀斯特石漠化防治工程技术研究中心, 贵阳 550001)
  • 出版日期:2019-07-10 发布日期:2019-07-10

Daily photosynthesis dynamics of different degraded Zanthoxylum bungeanum in karst rocky desertification area and its relationship with environmental factors.

TAN Dai-jun, XIONG Kang-ning*, ZHANG Yu, HANG Hong-tao, QUAN Ming-ying, JI Chuan-ze, MA Xue-wei, ZHANG Shi-hao   

  1. (School of Karst Science, Guizhou Normal University/State Engineering Technology Institute for Karst Desertification Control, Guiyang 550001, China).
  • Online:2019-07-10 Published:2019-07-10

摘要: 花椒是中国喀斯特石漠化地区重要的生态经济树种。为分析花椒在石漠化脆弱生境中光合生产能力,以轻度退化(LD)、中度退化(MD)、重度退化(SD)花椒为对象,研究花椒日光合特征变化及其与环境因子的关系,并采用通径分析法分析各环境因子对花椒净光合速率的直接或间接作用。结果表明:不同退化花椒的净光合速率日均值分别为3.53(LD)、2.85(MD)、2.32(SD) μmol·m-2·s-1;LD、MD、SD日光合同化量分别为141.21、113.44和94.97 mmol·m-2,SD光合同化能力显著低于LD、MD;LD表现出较高水分利用效率和叶片羧化效率,其值均高于MD、SD;各退化花椒气孔限制值日均值没有明显变化;LD净光合速率主要受空气CO2浓度和光合有效辐射的影响,同时空气温度与空气相对湿度之间的相互作用共同制约着净光合速率大小;光合有效辐射、空气相对湿度分别是MD、SD净光合速率的主导因子,而空气温度为其主要限制因子。因此,不同退化花椒光合作用对生理状况和自然环境条件的变化敏感性较强,光合生产力总体偏低。

关键词: 生态系统服务, 城市, 景观格局, 评价, 权衡

Abstract: Zanthoxylum bungeanum is an important ecological and economic tree species in karst rocky desertification area of China. We measured the photosynthetic productivity of Z. bungeanum in the fragile habitat with rocky desertification, including lightly degraded (LD), moderately degraded (MD) and severe degraded (SD) Z. bungeanum. Daily photosynthesis variations of Z. bungeanum and their relationships with environmental factors were examined. Moreover, the path analysis method was used to analyze the direct or indirect effects of environmental factors on the net photosynthetic rate (Pn) ofZ. bungeanum. Average daily Pn of LD, MD and SD were 3.53, 2.85 and 2.32 μmol·m-2·s-1, respectively. Diurnal photosynthesis assimilations of LD, MD and SD were 141.21, 113.44 and 94.97 mmol·m-2, with significantly lower value of SD than those of LD and MD. LD had higher water use efficiency and instantaneous carboxylation efficiency than MD and SD. Z. bungeanum with different degraded degrees showed no significant difference in average daily stomatal limiting value. Pn of LD was mainly influenced by CO2 concentration and photosynthetically available radiation (PAR). The interaction between air temperature (Ta) and relative humidity (RH) jointly restricted the value of Pn.PAR and RH were dominant factors influencing MD and SD respectively, with Ta as the major limiting factor. In conclusion, photosynthesis of different degraded Z. bungeanum was sensitive to the dynamics of physiological conditions and natural environment conditions, with relatively low photosynthetic productivity.

Key words: ecosystem services, urban ecology, landscape pattern, assessment, tradeoff.