金银花对土壤干旱—复水的光合生理响应

发布时间：2018-01-14 22:21

  本文关键词：金银花对土壤干旱—复水的光合生理响应　出处：《山东农业大学》2017年博士论文　论文类型：学位论文

  更多相关文章： 金银花 干旱胁迫 复水 光合作用 水分阈值

【摘要】：金银花在沂蒙山区被广泛用作水土保持造林和药用经济栽培植物,为沂蒙山区的生态恢复和经济发展做出了卓越贡献。但是沂蒙山区春夏季土壤重度干旱发生概率呈增大趋势,加之沂蒙山区干旱瘠薄的立地条件,增加了金银花受到重度干旱胁迫的风险,严重制约了金银花的生长发育和生产力。当土壤干旱发生后,金银花通过一系列生理生态学机制去抵御和适应胁迫,金银花光合生理对干旱胁迫的响应过程与复水后的恢复过程相关联,因此需要通过量化其光合生理参数与土壤水分含量的关系来对金银花外在形态特征和内部生理机制的变化过程进行深入的研究,以便对金银花进行科学高效的水分管理。但是目前关于金银花光合生理对干旱胁迫响应的研究尚少,关于重度土壤干旱胁迫对金银花光合生理的影响以及复水后金银花光合生理的恢复性尚未见报道,这些研究的缺乏不利于金银花应对干旱胁迫的水分管理措施体系的建立。本文以沂蒙山区常见的水土保持植物和经济树种——金银花一年生苗木为试验材料,于2016年3—10月在山东农业大学林学试验站温室内进行盆栽试验,并结合实验室室内分析试验,进行土壤水分的控制条件下金银花光合作用气体交换参数、叶绿素荧光参数、光谱特征参数和酶活性指标的监测,以净光合速率(Pn)、水分利用效率(WUE)为衡量土壤水分(RSWC)影响金银花光合作用产量和效率的指标(简称为“产”、“效”),以光合作用气孔调节机理、叶绿素荧光变化机理和叶片形态变化特征为依据,分析了金银花光合生理在“干旱胁迫—胁迫持续—复水”过程中的变化特征,探讨了金银花对连续多级土壤水分梯度、重度土壤干旱胁迫的光合生理响应以及重度土壤干旱后复水金银花光合生理的恢复性机理,并在此基础上,得出了从土壤饱和含水量至Pn=0土壤含水量(凋萎含水量,此时金银花开始萎蔫并逐渐凋落)范围内水分有效性分级体系和重度土壤干旱水分阈值(RSWCSL-NSL、RSWCPn=0),并根据金银花在重度干旱下光合作用“产”、“效”降到最低值的速度(简称为“速”)以及复水后金银花光合作用“产”、“效”恢复到最大值的速度(“速”),得出了基于“速—产—效”金银花响应干旱胁迫光合作用降低及复水后光合作用恢复性的关键阈值,形成了金银花在重度土壤干旱下光合作用降低及复水后光合作用恢复性的动态过程体系,为重度土壤干旱下金银花的水分管理工作提供科学依据,而且本文研究中确定的不同水分阈值具有普遍的生理生态学意义,对其它植物也具有适用性。论文主要的结论如下:1)金银花叶片光合作用气体交换参数、叶绿素荧光参数、光谱特征参数和酶活性指标对土壤水分含量(RSWC)具有阈值响应特征,土壤水分过高或过低都会影响金银花光合作用。基于金银花光合作用受抑制的特征将金银花从土壤饱和含水量至Pn=0含水量之间土壤水分范围按照水分胁迫程度划分为适宜金银花生长的水分范围(70.54%≤RSWC≤83.50%)、轻度水分胁迫水分范围(55.07%≤RSWC70.54%或RSWC83.50%)、中度水分胁迫水分范围(29.71%RSWC55.07%)、重度水分胁迫水分范围(RSWC≤29.71%)。以Pn和WUE为表征金银花光合作用“产”和“效”的指标,应用临界值分类法将土壤水分梯度分为“无产无效水”(RSWC≤13.82%)、“低产低效水”(13.82RSWC≤29.71%)、“中产中效水”(29.71%RSWC≤30.64%或RSWC93.39%)、“中产高效水”(30.64%RSWC≤51.53%)、“高产中效水”(83.76RSWC≤93.39)和“高产高效水”(51.53RSWC≤83.76%)6个等级(利用类型)。金银花重度干旱水分范围(RSWC≤29.71%)包括土壤水分有效性分级中的“低产低效水”和“无产无效水”,在该水分范围内,以金银花气孔机理转折水分点(RSWCSL-NSL)和Pn为0水分点(RSWCPn=0,即金银花叶片萎蔫水分点)作为金银花重度干旱胁迫的关键水分阈值。2)金银花对土壤水分胁迫的响应,同时与土壤水分胁迫程度及其胁迫持续时间有关。在重度土壤干旱各水分阈值(即水分阈值1:RSWCSL-NSL,水分阈值2:RSWCPn=0)及其胁迫持续时间(30d)耦合作用下,金银花净光合速率(Pn)、水分利用效率(WUE)、蒸腾速率(Tr)、气孔导度(Gs)、气孔限制值(Ls)、表观光合量子效率(Φ)、最大净光合速率(Pnmax)、光饱和点(LSP)、暗呼吸速率(Rd)、最大荧光(Fm)、PSⅡ最大光化学效率(Fv/Fm)、PSⅡ实际光化学效率(ΦPSⅡ)、表观光合电子传递速率(ETR)、叶绿素(Chl)荧光光化学淬灭(qP)、非光化学淬灭(NPQ)、水分指数(WI)、叶绿素归一化指数(Chl NDI)、归一化颜色指数(NDCI)以及超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)的酶活性显著降低,胞间CO2浓度(Ci)、光补偿点(LCP)、初始荧光(Fo)、光化学反射指数(PRI)、丙二醛(MDA)含量显著上升,导致金银花“产”、“效”下降的主要原因是非气孔限制,干旱胁迫期间金银花叶片出现萎蔫并逐渐凋落,叶片光合机构受到不可逆破坏,金银花光合产量严重降低。确定了水分阈值1(RSWCSL-NSL)、水分阈值2(RSWCPn=0)分别持续25d和5d的干旱胁迫为金银花基于“速—产—效”光合作用降低的水分阈值(即阈值1(25)、阈值2(5)),干旱胁迫重于此阈值时,Pn、WUE将达到最低值(0值)。3)金银花复水后光合作用的恢复性(恢复程度和恢复速度)同时与复水前重度土壤干旱不同水分阈值及其胁迫持续时间有关,而且金银花在重度土壤干旱后光合作用的降低和复水后光合作用的恢复性紧密联系。金银花在不同水分阈值(RSWCSL-NSL、RSWCPn=0)处分别进行持续胁迫后复水其气体交换参数、叶绿素荧光参数、光谱特征参数和酶活性指标在复水的前15d左右恢复相对较快,之后或者达到稳定状态或者继续缓慢恢复。根据金银花复水后光合生理的恢复性,将其在水分阈值2持续胁迫时的萎蔫情况分为临时萎蔫,即水分阈值2(RSWCPn=0)持续0d(阈值2(0))时的萎蔫;以及永久萎蔫,即水分阈值2(RSWCPn=0)持续10d以上(即阈值2(10)、阈值2(20)、阈值2(30))。以金银花“产”、“效”最高的水分处理(RSWC=79.59%)的光合生理参数平均值(PAR=1200μmol·m-2·s-1)为对照,以所有水分处理(土壤饱和含水量到Pn=0含水量)的光合生理参数平均值(PAR=1200μmol·m-2·s-1)为均值,对各复水处理光合生理参数的恢复效果进行评价。根据金银花在重度土壤干旱胁迫后复水光合作用基于“速—产—效”的恢复性,确定了RSWCSL-NSL持续0d的干旱胁迫(即阈值1(0))为金银花光合生理恢复性的第1级水分阈值,干旱胁迫轻于此阈值,复水15天内Pn、WUE恢复到甚至超过对照水平;以RSWCSL-NSL持续10d、RSWCPn=0持续0d的干旱胁迫(即阈值1(10)、阈值2(0))为恢复性的第2级水分阈值,干旱胁迫轻于此阈值而重于第1个阈值时,复水25d内Pn、WUE恢复至均值以上水平;以RSWCSL-NSL持续20d、RSWCPn=0持续10d的干旱胁迫(即阈值1(20)、阈值2(10))为恢复性的第3级水分阈值,当干旱胁迫重于此阈值时,复水到30d时,Pn、WUE都没有恢复到均值水平。
[Abstract]:Honeysuckle is widely used in Yimeng mountain afforestation and medicinal plant cultivation economy of soil and water conservation, made outstanding contributions to the ecological restoration of Yimeng mountain area and economic development. But the Yimeng mountain spring and summer soil increases the probability of occurrence of severe drought, drought and barren in Yimeng mountain area and site conditions, increasing the risk of severe drought stress by honeysuckle, serious restrict the growth and productivity of honeysuckle. When soil drought occurred, honeysuckle to resist and adapt to stress through a series of physiological and ecological mechanism, physiological recovery process of gold and silver money in response to drought stress and rewatering associated, so through the quantitative relationship between the photosynthetic physiological parameters and soil water content to change the honeysuckle external morphological characteristics and internal physiological mechanism of the process requires in-depth research, in order to in Honeysuckle The scientific water management efficiency. But the current research on the gold and silver money physiological response to drought stress is less about the reported recovery of severe effects of soil drought stress on Photosynthetic Physiology and all gold and silver after rehydration of gold and silver spend physioecological, the establishment of these studies lack is not conducive to the system of water management measures in response to the drought of honeysuckle stress. In this paper, the Yimeng mountain area common plant for soil and water conservation and economic species of honeysuckle seedlings as test materials, in 2016 3 to October at the Shandong Agricultural University Forestry Experimental Station in greenhouse pot experiment, combined with analysis of test laboratory, exchange parameters controlling conditions of soil moisture under honeysuckle photosynthesis chlorophyll fluorescence parameters of gas. Monitoring, spectral characteristic parameters and enzyme activity index, the net photosynthetic rate (Pn), water use efficiency (WUE) for The measure of soil moisture (RSWC) affect the yield and efficiency of photosynthesis index of honeysuckle (hereinafter referred to as the "production" and "efficiency"), stomatal regulation on the photosynthesis mechanism, chlorophyll fluorescence and leaf morphology change mechanism according to the variation characteristics, analysis of Photosynthetic Physiology in "all gold and silver drought - stress - complex variation of water" the study of honeysuckle on continuous multistage soil moisture gradient, severe soil drought stress on photosynthetic physiological response and severe soil drought rewatering after physiological recovery of gold and silver money mechanism, and on this basis, obtained from the soil saturated water content and Pn=0 of soil moisture (wilting, the honeysuckle began wilting and gradually fall within the scope of water availability) grading system and severe soil drought water threshold (RSWCSL-NSL, RSWCPn=0), and according to the degree of drought on Photosynthesis in heavy honeysuckle "Production" and "efficiency" to a minimum value of speed (referred to as the "speed") and after rewatering honeysuckle Photosynthesis "production", "effect" back to the maximum speed ("speed"), obtained based on the "speed - production effect of honeysuckle in response to drought stress reduced photosynthesis and water recovery after the recovery of photosynthesis of the critical threshold, the formation of honeysuckle in severe soil drought reduced photosynthesis and rehabilitation of water dynamic process of photosynthesis system recovery, and provide scientific basis for severe soil drought under honeysuckle water management work, and the research on different water threshold determined with universal significance of physiological ecology, it is applicable on the other plants. The main conclusions are as follows: 1) gas exchange parameters of honeysuckle leaf photosynthesis, chlorophyll fluorescence parameters, spectral characteristic parameters and enzyme activity index of soil moisture content (RSWC) with threshold response characteristics, soil moisture is too high or too low will affect the photosynthesis characteristics of honeysuckle honeysuckle. Photosynthesis inhibition based on honeysuckle from saturated soil water content and water content of Pn=0 soil moisture range according to the stress level is divided into the suitable moisture range of honeysuckle growth (RSWC = 70.54% ~ 83.50%), mild water water stress range (55.07% RSWC70.54% or RSWC83.50%), moderate water stress and water range (29.71%RSWC55.07%), severe water stress water range (RSWC < 29.71%). Pn and WUE for the characterization of honeysuckle Photosynthesis "production" and "efficiency" of the index, using the critical value method to soil moisture gradient is divided into "no property is invalid water" (RSWC 13.82%), "low efficiency water" (13.82RSWC = 29.71%), "the effect of middle water" (29.71%RSWC < 30.64% or RSWC93.39%), "middle high water" (30 .64%RSWC = 51.53%), "high efficiency water" (83.76RSWC = 93.39) and the "high water" (51.53RSWC 83.76%) 6 grades (by type). Honeysuckle severe drought water range (RSWC = 29.71%) including the classification of soil water availability in low yield water and no water production is invalid "in the moisture range, with honeysuckle stomatal mechanism turning moisture point (RSWCSL-NSL) and Pn 0 water points (RSWCPn=0, namely honeysuckle leaf wilting moisture point) as a key water threshold of severe drought stress.2 honeysuckle honeysuckle) response to soil moisture stress, and soil water stress degree and duration of stress in severe soil drought. The water threshold (i.e. water threshold 1:RSWCSL-NSL, water threshold 2:RSWCPn=0) and stress duration (30d) coupling, honeysuckle, net photosynthetic rate (Pn), water use efficiency (WUE), transpiration 閫熺巼(Tr),姘斿瓟瀵煎害(Gs),姘斿瓟闄愬埗鍊，

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