高粱论文：干旱胁迫及复水对高粱水分传导特性的影响.doc

高粱论文：干旱胁迫及复水对高粱水分传导特性的影响【中文摘要】水分亏缺是限制干旱、半干旱地区作物生长发育的重要因子之一,严重影响作物生长发育等一系列生理过程。目前,对高粱、甜高粱的研究主要是集中在逆境胁迫下生理生态指标的变化分析上,而对干旱胁迫及复水条件下根系水分运输能力的变化及与地上部光合特性、植株生长之间关系的研究较少。本研究通过盆栽抗旱性较强的高粱栽培品种晋杂4号和甜高粱雅津13号,较系统地研究和分析了高粱、甜高粱在不同程度水分亏缺及复水条件下叶片气体交换参数、根系水导及生长形态指标的变化,并分析了其间的关系。主要研究结果如下:1)高粱叶片净光合速率（Pn）、气孔导度（Gs）均随胁迫程度的加剧而降低;复水四天后恢复至对照水平。中度水分（MS）处理叶片的胞间CO2（Ci）最低,气孔限制值（Ls）最高,表明MS处理叶片Pn降低的主要原因是气孔限制;重度水分（SS）处理叶片的Ci最高,Ls最低,Gs最低,表明SS处理叶片Pn降低的主要原因是叶肉细胞光合能力下降引起的,表现为非气孔限制;复水后,胁迫处理叶片的Ls降低,Ci升高。可见,随着干旱胁迫程度的加剧,高粱叶片光合能力的下降有一个从气孔限制到非气孔限制的变化过程。MS处理叶片复水第一天时,Ls急剧下降,Ci迅速升高;SS处理叶片复水第二天时,Ls急剧降低,Ci迅速上升。高粱叶片的光化学效率（Fv/Fm比值）随着干旱胁迫程度的加剧逐渐降低,表明干旱胁迫增大了高粱叶片的光抑制程度,降低了光系统的原初光能转化效率;复水四天后,基本恢复至对照水平。随着干旱胁迫程度的加剧,胁迫处理叶片的实际光化学效率（PS）、光化学猝灭系数（qP）逐渐降低;复水第二天开始升高,可见PS、qP的恢复存在滞后效应。SS处理叶片的非光化学猝灭系数（NPQ）最大,MS处理次之,CK最小。表明胁迫过程中高粱叶片通过光合电子传递过程中的热耗散途径减少了过剩激发能的产生,减轻了干旱对高粱的伤害。2)水分条件显著影响了高粱根系吸水,不同水分条件下根系导水率（Lpr）表现为:中度水分（MS）处理对照（CK）处理重度水分（SS）处理;复水后,MS处理植株的Lpr缓慢上升;SS处理植株的Lpr急剧升高,复水第五天,极显著的高于MS处理,并且超过CK处理。进一步分析发现高粱在MS及CK处理下根长的增大有利于水分的吸收及传导,同时MS处理植株的叶表面积较CK的小,有效降低了叶片的水分散失;复水后,SS处理植株的根系各参数变化幅度不大,但Lpr迅速升高,主要原因可能是复水增大了根系的活性。其原因有待于进一步研究。3)不同水分条件下,甜高粱气体交换参数的变化为:SS处理叶片的Pn高于CK及MS处理;复水四天,三个处理间无显著差异。水分亏缺下,Gs表现为:重度水分处理对照处理中度水分处理;Ci的大小顺序为:CK处理叶片的Ci极显著的高于胁迫处理;胁迫处理叶片的Ls极显著的高于CK处理;复水三天后,三个处理叶片的Gs、Ci和Ls均维持稳定,处理间差异不大。干旱胁迫下,MS处理叶片的Ls较高,Ci及Gs较低;复水后,Ls逐渐降低,Ci升高,Gs增加,Pn逐渐上升至对照水平,表明气孔限制是影响Pn的主要原因。CK处理叶片的Ls最低,Ci最高,Gs较低,较低Pn的主要原因可能是叶肉细胞光合能力较低,CO2的利用率较低。SS处理叶片的Ls最高,Ci最低,Gs最高,可能与其较高的Pn有关;复水后,Ls降低,Ci升高,Gs降低,与CK的表现一致。随着干旱胁迫程度的加剧,甜高粱叶片的Fv/Fm比值逐渐降低;复水四天,三个处理间差异不显著。SS处理叶片的PS极显著的高于CK及MS处理;复水后降低。MS处理叶片的PS在水分亏缺时降低;复水后逐渐升高。qP的变化趋势与PS一致。甜高粱荧光参数的变化与其光合参数的变化相一致,在荧光水平上解释了甜高粱光合的变化。4)不同水分处理下,甜高粱根系Lpr表现为:重度水分处理对照处理中度水分处理;复水后,SS处理植株的Lpr与CK处理植株之间的差异不显著,MS处理植株的Lpr低于SS及CK处理的植株。研究发现,甜高粱在MS处理下具有较高的根系表面积,使其在单位时间内,单位压力梯度下流经单位根表面积（或长度）的水流降低。【英文摘要】Water deficit is an main limiting factor for crops growth and development in arid and semi-arid areas, it can severely affect a series of physiological processes of plant. At present, more researches were focused on the changes of physiological and morphological indexes of sorghum and sweet sorghum under adversity situations, While the relations of root water conductivity, photosynthesis and growth were little under drought stress and re-watering. In this study, a sorghum（Sorghumbicolor Moench,jinza4） and sweet sorghum（Sorghumbicolor yajin13） variety was selected as the experimental materials, and potted experiment was designed to study and analyse the changes of the leaf gas exchange parametes, hydraulic conductivity of root and morphological indexes of growth, and analyse the relations between these parameters. The key results as following:With the drying of soil, the leaf net photosynthetic rate （Pn） and stomatal conductance（Gs） of sorghum was reduced. After the forth day of re-watering, these parameters were gradually recovered to control level. Under moderate drought condition, the intercellular CO2 concentration（Ci） was the lowest, the stomatal limiting value （Ls） was the highest, which indicated that the reduction of Pn was mainly resulted from stomatal limitation; while for severe water stress, the Ci was the highest, while the Ls was the lowest and the Gs was minimum, which suggested that the decrease of Pn was mainly attributed to the decline of diachyma cells photosynthetic activity, namely, the non-stomatal limitation; After re-watering, Ls was reduced and Ci was increased. Visible, the decline of sorghum photosynthetic capacity has a variational process of from stomatal limitation to the non-stomatal limitation with the drying of soil. Under moderate water stress, after the first day of re-watering, Ls sharply declined, Ci rapidly increased; As for severe water stress, it was happened the second day. After re-watering, Ls was declined and Ci was increased. At the same time, with the drying of soil, maximal efficiency of PS（Fv/Fm） of sorghum was gradually reducede, which indicated that water stress enhanced the photoinhibition and reduced the efficiency of primary light energy conversion of PS, After the forth day of re-watering, it gradually recovered to control level. The actual photochemical efficiency （PS） and photochemical quenching coefficient（qP）was lower than control in the process of drought stress, After the second day of re-watering, these parameters were increased, which displayed that a certain hysteresis effect after re-watering.The non-photochemical quenching （NPQ） of sorghum was highest under SS treament, MS take the second place and the CK was lowest, which suggestted that a part light energy absorbed by PSwas dissipated and can protected the photosynthetic tissue, alleviate the influence of water stress on the sorghum.The water treaments significantly effect the water absorbing of root, The hydraulic conductivity（Lpr） of sorghum under different water conditions was that moderate drought treamentcontrol treament severe water treament; After re-watering, The Lpr of MS was slowly increased, While SS rapidly rised, after the forth day of re-watering, Lpr of SS was significant higher than MS, and even exceeded CK. Further analysises found that the root length increaed under MS, it was beneficial of water absorption and transportation. At the same time, The surface area of leaf was smaller than CK which can reduce the loss of water; After re-watering, The changes of root parameters were little under SS, While the Lpr rapidly increased, the main reason was probably that re-watering can increase the recovery capacity of root activity.Under different water conditions, The changes of leaf gas exchange parametes of sweet sorghum were that Pn of sweet sorghum leaf under SS condition was the highest, After the forth day of re-watering, There was no difference between three treaments. Under water stress, The performance of Gs was that SSCKMS; The Ci was that CK was significantly higher than MS and SS treaments; The Ls of MS and SS treaments was significantly higher than CK treament. After the third day of re-watering, The Gs、Ci and Ls maintain stability and there was no difference between three treamnents. The Ci and Gs of MS treament was reduced and the Ls was increased; After re-watering, Gs and、Ci was gardually rised, Ls was reduced, Pn recovered to control level, Showing that the reduction of Pn was mainly resulted from stomatal limitation. The Ls and Gs of CK treament was low, While the Ci was the highest, Which suggested that the decreased of Pn was mainly attributed to the reduced of diachyma cells photosynthetical ability, the utilization of CO2 was low. Under SS treament, the Ls was highes and Ci was lowest,maybe related to the low Pn; After re-watering, the Ls and Gs reduced, Ci was increased which was the same as conrtrol. With the drying of soil, Fv/Fm of sweet sorghum leaf was gradually reduced; After the forth day of re-watering,there was no difference between three treaments.PSof SS treament was extremely higher than CK and MS treament; and descend after re-watering. ThePSof MS treament was reduced;and begin to increase after re-watering. The changes of qP was the same asPS. The changes of fluorescence parameters were in line with photosynthetic parameters , which will explain the photosynthesis changes of sweet sorghum in fluorescence level.The performance of Lpr of sweet sorghum under different water conditions was that SSCKMS; after re-watering, the Lpr of SS treament was no difference with CK treament. The Lpr of MS treament was lowest. Further studies founding that the root surface area under MS treament was big, the water flow was reduced under unit time, unit pressure gradient and unit surface area of root.【关键词】高粱 甜高粱 干旱胁迫 复水 水力导度【英文关键词】Sorghum Sweet sorghum Water stress Rewatering Hydraulic conductivity【目录】干旱胁迫及复水对高粱水分传导特性的影响摘要6-8ABSTRACT8-10第一章 文献综述13-201.1 干旱胁迫及复水对作物生长发育的影响13-171.1.1 干旱胁迫及复水对作物根系生长发育的影响13-141.1.2 干旱胁迫及复水对作物冠部生长发育的影响14-161.1.3 干旱胁迫及复水对作物根冠关系的影响16-171.2 干旱胁迫及复水对根系水分传导的影响17-201.2.1 干旱胁迫及复水对根系吸水机制的影响17-181.2.2 根系水导的测定技术18-20第二章 试验方法及研究内容20-232.1 研究目的及意义202.2 试验材料与设计20-212.2.1 试验材料202.2.2 试验设计20-212.3 测定指标与方法21-222.3.1 气体交换参数的测定212.3.2 根系水导的测定212.3.3 根系形态指标的测定212.3.4 干物