植物代谢生态随有效水分变化的物理生理生化定量规律研究

The metabolic theory of ecology (MTE) that derived from the scaling relationships between physiological traits and body size in animals and physical temperature factors, which ignored physiological and biochemical mechanisms and effects of water in habitats, has been extended to characterize ecological and biological processes from cellular to global levels. Most debates that claim to validate or invalidate MTE have focused on testing its predictions, which showed that it should be improved. We have found that the quantitative relationship among allometric scaling exponents of the body size, stature and coverage-density, which are regulated by hydro-physio-ecological processes; the dynamics of metabolic coefficients changed with effective water following Michaelis-Menten equation. A hypothesis had been preliminarily proposed that metabolic ecological processes may be jointly regulated by physical, physiological, biochemical laws, organism’s size and stature, based on which a novel quantitative models was also developed. The main predictions was planned to test by measuring and analyzing the traits of structure, metabolism, productivity and temperature and moisture etc. at levels from organs, individuals, populations to communities and ecosystems under conditions of control and field gradient of moisture and temperature in plants with main living forms, metabolic and ecological types. The identity and/or difference of the parameters will be found and improved among species and types. It is the points of innovation that introduce of the Michaelis-Menten equation from the biochemistry to quantify the effect of effective water, the effect of stature and coverage on the regulation of scaling exponent and ability to predict the dynamic of metabolism changing with the temperature and moisture. A novel quantitative model for metabolic ecology based on physical, physiological and biochemical laws was hoped to be developed. The famous MTE may be expanded and improved to be better for suiting the actual mechanisms of metabolic regulations in organisms especially in plants, which may improve the predictions for the responses of metabolism and distribution patterns changed with temperature, moisture and climate in vegetation.

源于动物生理和物理原理的代谢生态理论给出代谢随体积和温度变化的规律并被扩展到各类生物各尺度生态研究，然而因其忽视生理生化调控尤其是生境水分对植物代谢和体形的调控，虽获很大成功但也引发激烈争论质疑，亟待改进。我们发现其体积异速指数随体形和盖度指数定量变化并受有效水分调控，代谢参数随有效水分变化的轨迹符合生化米氏方程。初步提出植物代谢生态的物理生理生化调控方程及其可检验预测，计划进行多物种多尺度研究和检验。拟在控制和自然条件下，选择主要生活、光合代谢和水分生态型的植物，分别在器官、个体、种群和群落水平，测定主要结构、代谢、生产力等指标和生境温湿度；分析其种间和类型间的异同和变化规律，多尺度检验主要预测。在引入体形生理调控、有效水分生化动态和赋予代谢随温湿度2维变化的计算预测能力等有创新；可使该理论克服其参数检验不符引发的争论质疑；使其从体积物理定量方程进步为体积体形物理生理生化定量方程。

广泛应用的代谢生态规律3/4 Power Law 遭遇持续百年的指数变异、对数非线性和机理不清等严重争论和挑战，植物代谢更有光合作用和气孔调控等特殊问题。本项目从植物代谢生理生化原理和气孔、器官、体积效应及其信号和生境调控入手，取得如下进展：1 光合产物葡萄糖和甘露糖通过钙信号、钙离子通道和水通道诱导气孔关闭；2 葡萄糖通过己糖激酶(HXK1) 和PYR/RCAR 受体诱导气孔关闭；3 在无体积效应下，植物最大代谢速率随有效水、光等变化动态符合酶动态；4 不同生境植被间的能量可能并不守恒质疑“能量守恒”律；5 叶形、功能群和生境显著调控植物代谢动态；6 植被代谢指数和δ13C随海拔高度和湿润度升高；7小球藻经氧化酶产生ROS诱导 气孔关闭改善水分利用效率；8 限速酶制约植物代谢和生长的相对速率；9 创建新代谢生态生理生化模型：在代谢和生长均有相同限制因子条件下，整合“代谢对数（lnQ）的有效底物依赖公式”和“体重对数(lnm)的有效底物依赖公式”得到“酶驱动的lnQ与lnm相互依赖规律”； 10 植物种间和尺度间数据支持新规律，尤其是植物代谢生态响应有效水分的的系统检验；11 新规律在原核、原生和动物种和类群间得到支持。获得了植物代谢生态的一系列代谢与细胞信号、酶、叶、体型和生境有效水分等因子的新调控机制，创建的新模型和规律，不仅可在Km≠KQ下，解释各类代谢生态的对数非线性问题，还可在Km=KQ下，得到Power Law，揭示其源于酶动态而非面积/体积比，几何或分形结构等。不仅证明叶面微生物和代谢产物等反馈调控气孔和光合速率的信号和分子机制，植物代谢响应有效水分等因子的生理生态机制，还首次建立了宏观生态和酶动态间的定量联系，获得比Power Law更具普适性的新的代谢生态规律。有望改进代谢生态理论，推进其在农林渔和药代动力学的更好应用。新代谢规律引入生态承载力可导出新的更符合实际数据的植物体积/产量随密度变化动态的定量规律，如能支持继续研究有望改进恒产定律和自疏法则等。