摘要
以10%和20%聚乙二醇(PEG6000)模拟干旱胁迫处理弗吉尼亚栎2年生扦插苗木,研究不同程度干旱胁迫下弗吉尼亚栎叶片相对含水量、水势以及质膜透性、游离脯氨酸含量变化和叶绿素荧光特性。结果表明:在10%PEG胁迫下,弗吉尼亚栎叶片水势和相对电子传递速率(rETR)明显下降(p<0.05),游离脯氨酸含量、相对电导率、丙二醛含量和非光化学淬灭系数(NPQ)以及热耗散速率(Drate)明显增加(p<0.05),而光化学淬灭系数(qP)、光化学反应速率(Prate)以及光合功能相对限制值(LPFD)变化不大;在20%PEG胁迫下,qP和Prate明显下降,叶片水势的下降幅度和游离脯氨酸的增加幅度明显加大,丙二醛含量、相对电导率和NPQ以及Drate持续增加,但增加幅度与10%PEG处理下相比差异不明显(p>0.05);而叶片相对含水量和初始荧光(Fo)、最大荧光(Fm)、PSⅡ最大光能转化效率(Fv/Fm)、PSⅡ的潜在活性(Fv/Fo)和PSⅡ实际光能转化效率(ΦPSⅡ)在10%和20%PEG胁迫下变化均不大,与对照相比无明显差异(p>0.05),表明在PEG胁迫下弗吉尼亚栎叶片具有较好的保水能力,而且良好的热耗散机制使得叶片光合结构即使在较高浓度的PEG胁迫下仍能维持较好的活性,这可能是弗吉尼亚栎对干旱胁迫的一种适应性反应。
By adding lower concentration（10 %） and higher concentration（20 %） of PEG6000 into Hoagland solution to simulate different gradient drought stresses,the relative water content,water potential,relative penetrability of cell membrane,the proline content,the chlorophyll content and the ratio of chlorophyll a and b and chlorophyll fluorescence in leaves of Quercus virginiana were investigated.The results showed that when treated with lower concentration（10 %）of PEG,the water potential and the relative rate of electron transport（rETR） decreased with the proline content,relative conductivity,malondialdehyde（MDA） content,non-photochemical quenching（NPQ）and the rate of thermal dissipation（Drate）increased significantly（p〈0.05）,while the coefficient of photochemical quenching（qP）,the rate of photochemical reaction（Prate）and relative limit of photosynthesis（LPFD）changed slightly.Whereas the concentration of PEG was increased to 20 %,qP and Prate decreased significantly（p〈0.05）,the MDA content,relative conductivity,NPQ and Drate had a sustained increase,while the water potential decreased and the proline content increased more significantly.The relative water content,the minimal fluorescence（Fo）,the maximal fluorescence（Fm）,maximal quantum yield of PSⅡ（Fv/Fm）,the potential activities of PSⅡ（Fv/Fo） and actual photochemical efficiency of PSⅡ（ΦPSⅡ）were almost unaltered under both lower and higher concentration of PEG,which indicated there may be a better water-holding capacity in leaves of Q.virginiana when exposed to drought stress.Moreover,the photosynthetic apparatus could keep stable activity by moderately thermal dissipation mechanism in leaves of Q.virginiana,which could be considered as an adaption of Q.virginina to drought sress.
出处
《南京林业大学学报（自然科学版）》
CAS
CSCD
北大核心
2011年第6期6-10,共5页
Journal of Nanjing Forestry University：Natural Sciences Edition
基金
"十一五"国家科技支撑计划(2006BAD03A1401)
浙江省科学技术厅重点项目(2007C22075)
