根系温度对光核桃幼苗光合机构热稳定性的影响  

EFFECTS OF ROOT TEMPERATURE ON THERMOSTABILITY OF PHOTOSYNTHETIC APPARATUS IN PRUNUS MIRA SEEDLINGS

作　　者：郝海平[1,2] 姜闯道[1] 石雷[1] 唐宇丹[1] 姚涓[1] 李志强[3] 

机构地区：[1]中国科学院植物研究所,北京100093 [2]中国科学院研究生院,北京100049 [3]北京市农业职业学院,北京102442

出　　处：《植物生态学报》2009年第5期984-992,共9页Chinese Journal of Plant Ecology

基　　金：中国科学院创新工程重要方向项目(KSCX2-YW-N-52和KSCX2-YW-N-044);科技部项目(2008GB24910475和2006BAD26B0101);国家自然科学基金(30770223和30871455)

摘　　要：以光核桃(Prunus mira)幼苗为材料,通过控制根系温度研究了根系温度变化与叶片脱落酸(ABA)的关系及其对光合机构热稳定性的影响。结果表明:1)环境高温(37和40℃)胁迫下保持根系温度适宜((25±2)℃)时,幼苗叶片相对含水量(Relative water content,RWC)下降较少,但叶片ABA含量低,超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、过氧化物酶(POD)和过氧化氢酶(CAT)活性低,过氧化氢(H2O2)含量和膜质过氧化水平(丙二醛(Malondialdehyde,MDA)浓度)提高,最大光化学效率(Fv/Fm)下降程度较大;2)而同等环境高温(37和40℃)条件下根系温度逐步升高时,幼苗叶片RWC降低,叶片ABA含量增加,SOD、APX、POD、CAT活性高,H2O2含量高,MDA生成量低,Fv/Fm降低程度较小。与37℃相比,40℃处理条件下各生理指标变化趋势相似,但差异加大。因此认为:高温胁迫条件下,根系温度适宜时RWC高,但导致光合机构伤害较重;根系感受高温胁迫能够增加叶片ABA含量,有助于保护光合机构、提高光合机构的抗热性。Aims High temperature is one of the major abiotic factors that limit plant growth and development in many regions of the world. Although plant thermo-tolerance has been extensively investigated,little attention has been paid to the effects of root temperature on thermo-stability of the photosynthetic apparatus. Our objective was to investigate the effects of variation in root temperature on photosynthetic apparatus and explore potential mechanisms. Methods Under high air temperature （37 and 40 ℃）,root temperatures of Prunus mira seedlings were increased gradually （variable root temperature） or kept at （25±2）℃（appropriate root temperature） throughout the treatment. We examined relative water content, H2O2 concentration, malondialdehyde （MDA） concentration, activity of antioxidant enzymes, cholorophyll a fluorescence and ABA content in leaves. The experimental design was completely randomized, and each treatment was replicated at least three times. Important findings The combination of high air temperature and appropriate root temperature induced a decrease in activities of antioxidant enzymes and maximum quantum yield of PSII （Fv/Fm） with rela- tively high leaf relative water content （RWC）. Hydrogen peroxide （H202） and MDA increased, indicating the photosynthetic apparatus was damaged by high temperature. The combination of high air temperature and gradually increasing root temperature reduced damage to the photosynthetic apparatus with significant improvement in antioxidant enzymes activities and leaf ABA content. Therefore, root temperature plays an important role in enhancing the thermo-stability of the photosynthetic apparatus. First, roots at appropriate temperature maintain high relative water content of leaves, but have damagedphotosynthetic apparatus. Second, roots sensed the temperature stimulus and increased the leaf ABA accumulation when root temperature increased gradually, and high leaf ABA level prevented damage to the photosynthetic apparatus and enhanced heat

关 键 词：高温胁迫 抗氧化酶 过氧化氢 荧光 光核桃 

分 类 号：S945[农业科学—水产养殖]