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, nonphotochemical 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 waterholding 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.
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References
[1]Haller J M. Quercus virginiana: the southern live oak[J]. Arbor Age, 1992, 12(5):30.
[2] Harms W R. Quercus virginiana Mill. live oak[G]// Burns R M, Honkala B H. Technical Coordinators. Silvics of North America: Vol. 2, Hardwoods Agric Handb 654. Washington D.C:US Department of Agriculture, Forest Service,1990.
[3]陈益泰，陈雨春，黄一青，等．抗风耐盐常绿树种弗吉尼亚栎引种初步研究[J]．林业科学研究，2007，20(4)：542-546.
[4] 夏扬，秦江涛，朱晓军，等．不同有机物添加方式下水稻对干旱胁迫的响应[J]．土壤，2009，41(1)：118-125.
[5] 王洪春．植物抗逆生理[J]．植物生理学通讯，1981，17(2)：72-81.
[6] 单长卷， 郝文芳，梁宗锁，等．不同土壤干旱程度对刺槐幼苗水分生理和生长指标的影响[J]．西北农业学报，2005，14（2）：44-49.
[7] 付士磊，周永斌，何兴元，等．干旱胁迫对杨树光合生理指标的影响[J]．应用生态学报，2006，17（11）：2016-2019.
[8] 王兰兰，张立军，陈贵，等．甘薯愈伤组织对干旱胁迫和盐胁迫的生理反应对比[J]．生态学杂志，2006，25(12)：1508-1514.
[9] 王树凤，陈益泰，孙海菁，等．盐胁迫下弗吉尼亚栎生长和生理生化变化[J]．生态环境，2008，17(2)：747-750.
[10] Micher B E, Kaufaman M R. The osmotic potential of polyethylene glycol 6000[J]. Plant Physiology, 1973, 51:914-916.
[11] 中国科学院植物生理研究所.现代植物生理学实验指南[M]．北京：科学出版社，1999．
[12] Yin C Y, Berninger F, Li C Y. Photosynthetic responses of Populus przewalski subjected to drought stress[J]. Photosynthetica，2006，44: 62-68.
[13] Subrahmanyam D, Subash N, Haris A, et al. Influence of water stress on leaf photosynthetic characteristics in wheat cultivars differing in their susceptibility to drought[J]. Photosynthetica, 2006，44: 125-129.
[14]Kobliek M, Kaftan D, Nedbal L. On the relationship between the nonphotochemical quenching of the chlorophyll fluorescence and photosystem Ⅱ light harvesting efficiency. A repetitive flash fluorescence induction study[J]．Photosynthesis Research，2001，68：141-152．
[15] Zhou Y, Lam H M, Zhang J. Inhibition of photosynthesis and energy dissipation induced by water and high light stresses in rice[J]. Journal of Experimental Botany, 2007, 58:1207-1217.
[16] 贺少轩，梁宗锁，蔚丽珍，等．土壤干旱对2个种源野生酸枣幼苗生长和生理特性的影响[J]．西北植物学报，2009，29(7)：1387-1393.
[17] 章崇玲，曾国平，陈建勋．干旱胁迫对菜苔叶片保护酶活性和膜脂过氧化的影响[J]．植物资源与环境学报，2000，9(4):23-26.
[18] 刘祖祺．植物抗逆生理学[M]．北京：中国农业出版社，1993．
[19] 陈少瑜，郎南军，李吉跃, 等．干旱胁迫下3树种苗木叶片相对含水量、质膜相对透性和脯氨酸含量的变化[J]．西北林业科学，2004，33（3）：30-33,41.
[20]Demmig B, Bjǒrkman O. Comparison of the effect of excessive light on chlorophyll fluorescence(77K) and photon yield of O2 evolution in leaves of higher plants[J]．Planta，1987，171：171-184.
[21]张守仁．叶绿素荧光动力学参数的意义及讨论[J]．植物学通报，1999，16(4)：444-448．
[22]Maxwell K, Johnson G N. Chlorophyll fluorescencea practical guide[J]. Journal of Experimental Botany, 2000, 51:659-668.
[23]窦新永，吴国江，黄红英，等．麻疯树幼苗对干旱胁迫的响应[J]．应用生态学报，2008,19(7):1425-1430.
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