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树干/枝呼吸是调控森林碳平衡的关键生理过程之一,其对环境变化的响应在很大程度上决定了森林生产力及其固碳增汇能力。本文主要综述了近10年来林木树干/枝呼吸对大气CO2浓度升高、温度升高、干旱胁迫和人为管理的响应及其生理生态学调控机制,结果表明:大气CO2浓度升高和升温一般促进树干/枝的呼吸,其表观温度敏感性(Q10值)受树种、测定方法、温度范围、季节、林龄和径阶的影响,但变幅小于根系呼吸Q10值的变幅;干旱胁迫时,树干/枝呼吸速率减缓,随后进行浇水则会引发树干/枝呼吸的剧增,其生理学机制仍不清楚;不同的管理措施(如火烧、施肥、灌溉、修枝、环割等)对树干/枝呼吸的影响不尽相同。综述以往研究,提出今后值得深入探讨的4个方向:(1)明确树干/枝呼吸释放CO2的来源和去向以及建立相应的测定标准;(2)了解树干/枝呼吸对环境变化响应的生物学机制;(3)探讨树干/枝呼吸对环境变化的适应性;(4)树干液流、同位素示踪和CO2微电极技术的综合应用。
Trunk / branch respiration is one of the key physiological processes that regulate the carbon balance of forests. Its response to environmental changes largely determines the productivity of forests and their ability to increase carbon sequestration. In this paper, the responses of tree trunk / branch respiration to atmospheric CO2 concentration, temperature increase, drought stress and man-made management and their physiological and ecological regulation mechanisms in recent 10 years were reviewed. The results showed that the increase of atmospheric CO2 concentration and the general promotion of warming The apparent temperature sensitivity (Q10) of trunk / branch respiration was affected by tree species, measurement methods, temperature range, season, stand age and diameter but the amplitude was less than that of root respiration Q10; , Slowing of the trunk / branch respiration rate and subsequent watering will trigger a sharp increase in trunk / branch respiration, the physiological mechanisms of which remain unclear; different management measures (eg, burning, fertilizing, irrigation, pruning, ring cutting, etc.) The effects of trunk / branch breathing vary. In this paper, we summarize the previous researches and put forward four directions which should be further explored in the future: (1) to clarify the source and destination of CO2 released by trunk / branch breaths and to establish corresponding measurement standards; (2) to understand the biology of response of trunk / branch breaths to environmental changes Mechanism; (3) to explore the adaptability of trunk / branch respiration to environmental changes; (4) comprehensive application of sap flow, isotope tracing and CO2 microelectrode technology.