树木根系呼吸及其对环境的反应研究进展

Reviews on Root Respiration and It Responses to Environment Changes

对根系呼吸在植物生态系统碳平衡中的作用、根系呼吸的碳消耗、根系呼吸与林木生长间的关系、土壤温度、CO2、养分以及水分对根系呼吸的作用等方面进行了综述。结果认为,由于根系呼吸占土壤碳释放的40%～70%,是土壤碳过程的一个重要环节,是植物生态系统碳平衡的重要组成成分。植物通过根系呼吸可消耗8%～52%的叶片光合作用所固定的碳,是影响植物生态系统初级生产力的重要因素。通常根系维持呼吸占根系呼吸的大部分,它在一定范围内随根系年龄的升高而提高。土壤温度和CO2对根系呼吸的作用有一定争议,但普遍认为CO2体积分数升高大幅度降低根系呼吸强度,土壤温度升高会显著提高根系呼吸强度。土壤养分对根系呼吸的影响主要起因于根系生长和根系吸收养分对能量的消耗,尤其是根系蛋白质的周转和修复对能量的消耗。土壤水分显著影响根系呼吸强度,但这方面的研究较少。

The function of root respiration in carbon budget in plant ecosystem, the carbon dissimilation by root respiration, the relationship between root respiration and tree growth, and the functions of soil temperature, soil CO2 concentration, soil nutrients and soil moisture on root respiration are reviewed in the paper. Results showed that root respiration is a key process and an important component in carbon budget in plant ecosystems because carbon release from root respiration accounts for 40% ～ 70% of total carbon releases from soil respiration. Root respiration is also an important factor which influences the prime productivity of plant ecosystems judging from the fact that it can dissimilate 8% ～ 52% of carbohydrates assimilated by leaf photosynthesis. The maintenance respiration which takes majority proportion of total root respiration increases with root age. The effects of soil temperature and soil CO2 on root respiration are controversial, but most researchers think that elevated CO2 can reduce root respiration rate and elevated soll temperature can enhance root respiration rate. The effects of soil nutrients on root respiration are caused by energy requirement for ion uptake and root development, especially for protein turnover and repair. Root respiration is obviously influenced by the changes of soil moisture, but few relevant researches have been published.