【作者】 郭璟；

【导师】 应叶青；

【作者基本信息】 浙江林学院 ， 森林培育， 2009， 硕士

【摘要】 为探明毛竹(Phyllostachys heterocycla var. pubescens)幼苗干旱胁迫下生理响应机制,采用盆栽的方法,测定毛竹幼苗在无胁迫(CK)、轻度胁迫(LS)、中度胁迫(MS)、重度胁迫(HS)及自然干旱下的细胞膜透性、水势、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性、丙二醛(MDA)、叶片色素含量、光合参数及叶绿素荧光参数及成像动态变化。结果表明夏季和秋季实验阶段的研究结论基本一致:(1)随着胁迫程度加深,叶组织水势下降,电导率上升,二者回归分析表明相关性不显著(R=0.054);复水可促使不同梯度干旱胁迫及自然干旱胁迫后叶片质膜透性恢复。(2)SOD活性LS处理下降17.1639%,MS、HS处理分别上升12.7067%和29.00%;CAT活性、MDA含量均随胁迫程度加深而升高;复水后CAT活性、MDA含量下降,SOD活性变化规律不明显。(3)光谱法测定毛竹幼苗叶绿素含量结果科学可靠(与浸提法测定相关系数R=0.9994),光谱法结果表明LS处理叶绿素、花青素含量升高,MS、HS处理下降且各处理间差异性显著(P≤0.05)。浸提法结果表明叶绿素含量、叶绿素A、叶绿素B变化趋势基本一致,十月阶段LS>CK>MS>HS,八月阶段CK>LK>MS>HS。随着自然干旱的持续总叶绿素、叶绿素A、叶绿素B含量总体呈现先增加后下降趋势,复水后略有回升。(4)随着胁迫程度的加深,光合速率、蒸腾速率、气孔导度下降,气孔限制是其光合速率降低的主要原因;土壤含水量在一定范围内是影响光合速率的重要因子。毛竹幼苗光合参数存在最适水分环境,过少或过多的水分都将降低毛竹幼苗的光合能力,抑制光合作用。一、二年生毛竹幼苗光合能力较适宜的含水量区间为田间持水量的50%至65%。(5)不同水分胁迫下毛竹PSⅡ反应中心受到破坏或可逆失活,导致Fo增加,Fm、Fv/Fm、Yield降低;各荧光参数达到稳态后成像的异质性明显不同;一年生幼苗自然干旱胁迫过程中当相对含水量降至17.68%后、二年生幼苗降至51.33%后Fv/Fm极显著降低出现光合机构的伤害,复水后可恢复。更多还原

【Abstract】 The membrane permeability,leaf water potential,Superoxide Dismatase (SOD),Atalase(CAT),Malondialdehyde(MDA),pigment content,photosynthetic parameters ,chlorophyⅡd ynamics and fluorescence imaging was conducted with the leaves of 1-year-old and 2-year–old Phyllostachys heterocycla var.pubescens under natural drought and re-watering and different water deficiency conditions (well watered(CK),little mild stres(sLS),moderate stress(MS),severelys stress(HS)),by pot culture method.The results were the same between conculusions of summer and autumnas,as follows:(1) From well watered to severely stress watered,the conductivity increased,leaf water potential decreased,and correlation is not significan(by regression analysis,R=0.054). Different gradient of water deficit stress treatment and natural drought,after rehydration The membrane permeability can recover after re-watering.(2)From well watered to severely stress watered and natural drought,the activity of SOD decreased 17.1639% at LS treatment,then increased;while the activity of CAT and MDA content increased gradually,then decreased after re-watering.The activity of SOD was not obvious in the process of natural drought and re-watering.( 3 ) By Spectrometry , chlorophyll content of bamboo seedlings were reliable( R=0.9994);while the variation of average of it is similar with other pigment content.by Extraction,increased the content of chlorophyll a,chlorophyll b and total chlorophyll were gradually decreased in the process of natural drought and from CK treatement to HS treatement. After re-watering,the content of chlorophyll a,chlorophyll b and total chlorophyll regained in natural drought and CK,LS,MS treatment,but HS treatment.(4)From well watered to severely stress watered,the net photosynthetic rate (A),transpiration rate(E),stomatal conductance (GH2O)were declined,and which mainly resulted from stomatal limitation.The water content around 50%-60% were suitable.(5)From NS treatment to HS treatment, Fm, Fv / Fm,Yield reduced,while Fo increased. The heterogeneity of chlorophyll fluorescence parameters Fo、Fm、Fv/Fm was significantly different . PSⅡapparatus damaged ( 1-year seeding at 17.68% water contentduring;2-year seedings at 51.33% water content)in the process of natural drought,and could restore after re-watering.更多还原