数字、热红外和显微图像解析法对一些树木水分和能量失衡的解析

The trees in persistent water and energy imbalance not only show the characteristics of leaf reddening, leaf scorches as well as whole plant wilt, but also sometimes present disorders of nutritional imbalance, low resistance to stresses and low growth ability. The appliers have found that the water and energy balance was corresponding to their structure and functions, when they quantitatively studied the tree characteristics responding to the extreme dry and hot environment with the analysis technology of digital and IR thermo images. In this projects, we plan to further study the stress characteristics and hazardous risk caused by the extreme environments of too-high and too-low of soil water content, nutrition content and air temperature as well as over-amount of soil salt and their linkages. We also plan to further study the relationship between spatial structure and distribution of stomata and energy balance of these trees; to analyze the environmental sensitivity of plant or trees and damage mechanism within the stomata incomplete period of their growth and development. The mechanism of water and energy imbalance affecting the nutrition balance，resistant ability to stresses as well as growth and breeding will be generally studied by using imaging methods combining with the meteorological analysis， measurement of leaf water potential, transpiration strength, stomatal conductance, and photosynthesis.

持续的植物水分和能量失衡不仅表现在其叶变色、叶尖叶缘焦枯和整株枯萎等特征，而且涉及其营养平衡、抗逆能力和生长发育。申请人在2012-2015年获助的国家自然科学基金项目中利用数字、热红外成像等生态信息技术量化研究一些树种响应极端干热环境的特征时发现，植物水分和能量平衡与其结构和功能相统一。本研究拟在极端气象事件频发的背景下，综合运用数字和热红外成像等生物物理方法结合生化研究和室内模拟渗透实验，深入探讨土壤水分过多和过少、营养元素过多或过少、温度过高或过低以及土壤盐分过高等极端环境对植物或树木的胁迫特征和致灾风险。进一步深入研究树木气孔空间分布和结构与其能量代谢平衡的关系，探索生长发育的窗口期对胁迫事件及其链接的敏感性和受害机制。结合叶片的水势、蒸腾强度、气孔导度和光合作用强度等生理指标的测定和气象资料分析，用图像解析法从整体上探索树木水分和能量失衡作用于营养平衡、抗性能力和生长发育的机理。

本项研究是国家自然科学基金项目“用热红外成像技术研究一些树木响应极端干热环境的特征和机理(31170671)”的继续。该项目利用热红外成像等技术量化研究了一些树种响应极端干热环境的过程中呈现的叶变红、叶尖叶缘焦枯和整株枯萎等特征和机理。本项目（31770770）立足于综合运用数字、热红外和显微成像等生物物理方法结合生化研究和创新实验等，深入探讨土壤水分过多和过少、营养元素过多或过少、温度过高或过低以及土壤盐分过高等极端环境中树木水分和能量失衡的表现形式和特征。深入研究树木气孔空间分布和结构与其能量代谢平衡的关系，探索生长发育的窗口期对胁迫事件及其链接的敏感性和受害机制。结合叶片的生理指标的测定和气象资料分析，用图像解析法从整体上探索树木水分和能量失衡作用于营养平衡、抗性能力和生长发育的机理。.在项目的实施中，通过热红外指温差值、叶片受害内角、G/L色值、叶卷角、树冠指数、气孔开闭度和发育度等创新技术和指标的应用，结合叶片切脉、饱和蔗糖渗透胁迫、叶绿素光解、水培、遮荫、水淹、SO2熏蒸等试验以及气象大数据的分析，从树木器官和组织层面深入研究了其表型特征与水分和能量代谢平衡的关系。 确立了景观树木水分和能量失衡下“发烧”的临界范围和优化的指温差检测技术，探明了乡土树种适应环境的优越性。.研究表明外在的极端环境往往通过作用于内在的水分和能量平衡影响植物。树木的失绿黄化和营养失衡、局部滞绿等抗性反应、冠形的分化以及生长衰退甚至枯萎等往往发生在持续的水分和能量的失衡之后，是其枝叶持续”发烧”的结果。树木的水分和能量失衡时而起因于一些间接的、潜隐性极端环境的链接。在此基础上，发现了植物或树木叶绿素光降解和光合叶面积滞育和缩减与水分和能量失衡有关。明确了幼叶易于敏感变色的自立窗口期的存在以及叶变色的光保护机制。该项研究的方法和理论创新将对生产、科研和教学活动具有明显的促进作用, 对大面积的栽培植被防灾抗灾和可持续发展具有深远的意义。