碱性盐胁迫对桑树幼苗叶片叶绿素荧光和激发能分配的影响  

Effects of chlorophyll fluorescence characteristics and energy allocation pathways in leaves of mulberry seedlings under alkali salt stress

作　　者：张会慧[1] 张秀丽[1] 胡彦波[1] 李鑫[1] 许楠[1] 王鹏[1] 梁明[1] 孙广玉[1] 

机构地区：[1]东北林业大学生命科学学院,黑龙江哈尔滨150040

出　　处：《经济林研究》2012年第1期6-12,共7页Non-wood Forest Research

基　　金：国家自然科学基金项目(31070307;30771746);黑龙江省自然科学基金重点项目(ZD201105);国家科技支撑项目(2011BAD08B02-3);国家林业局重点项目(2010-29;2011-32)

摘　　要：为揭示桑树叶片光合特性在不同pH值碱性盐胁迫下的适应机制,以2种中性盐(NaCl和Na2SO4)、2种碱性盐(NaHCO3和Na2CO3)按不同比例混合,研究了不同pH值碱性盐对桑树幼苗叶片叶绿素荧光特性和激发能分配的影响。结果表明:在100 mmol·L-1的混合碱性盐胁迫下,桑树幼苗叶片的叶绿素荧光和激发能分配参数主要受盐溶液中的pH值和CO32-浓度的影响,而其它离子的作用较小。在pH9.0以下的碱性盐胁迫下桑树幼苗叶片的PSⅡ仍然可以提供足够的高能电子,进行正常的电子传递,而当pH值增加到10.0时,各荧光参数变化剧烈,PSⅡ反应中心活性和反应中心开放程度降低,叶片的电子传递受阻,并且高pH值的碱性盐引起光合原初反应过程受到抑制主要是由于PSⅡ电子受体侧受到抑制引起的,而对PSⅡ电子供体侧放氧复合体(OEC)伤害程度较小。PSⅡ反应中心无法正常接受光量子,光能用于光化学反应的比例降低。高pH值碱性盐胁迫还改变了桑树幼苗叶片PSⅡ对光能的吸收、转化和热耗散的状况,碱性盐胁迫下PSⅡ反应中心吸收的光能的分配参数受pH的影响较明显,桑树幼苗主要通过增加剩余有活性反应中心的活性来维持PSⅡ反应中心的正常生理功能,并且通过增加热耗散的比例来降低激发能的产生,而叶黄素循环在高pH值碱性盐胁迫下的光保护功能受到破坏。吸收光能的重新分配在维持高pH值碱性盐胁迫下桑树幼苗叶片光能吸收和利用之间的平衡具有重要的作用,这是桑树幼苗对高pH值碱性盐胁迫的一种适应机制。Abstract： In order to reveal the adaptive mechanism of photosynthetic characteristics of mulberry leaf under alkaline stress at different pH values, the effects of alkali salt stress at different pH values on chlorophyll fluorescence and energy allocation pathways in mulberry seedlings leaves were researched, which were treated in stress concentration mixed two neutral salt （NaCl and Na2SO4） and other two alkaline salt （NaHCO3 and Na2CO3） according to certain ratio. The results showed that these parameters of fluorescence and energy allocation were mainly determined by pH value and CO32 concentration under 100 mmol＇L~ mixture of alkaline-salt at different pH value, while the effects of other ions couldbe neglected. In the stress situation of below pH value 9.0, PS II of mulberry leaf seedling could provide enough high- energy electrons for electron transfer, while in the stress situation of pH value 10.0, the fluorescent parameters were changed significantly, the activity and opening degree of PS II reaction center was decreased obviously, the electronic transfer was impeded, the PS II reaction center was normally accepted photon, and the proportion of energy used for photochemical reaction was reduced. The results of the study showed that the process of photosynthetic original reaction was restrained under high pH value of alkaline salt, which was caused by the restraint of PS II electronic receptors side, and the effects of oxygen complex （OEC） of PS II electron donor side could be neglected. The functions of PS II such as photon absorption, utilization and dissipation were changed by alkaline salt stress at high pH value. Meanwhile, these parameters of energy distribution were affected by pH value obviously. In addition, the normal physiological function in mulberry seedling under alkaline salt stress at high pH value were depended upon increasing the proportion of activation of residual-activity response center, and excitation energy in mulberry seedling leaves were reduced mainly depend upon

关 键 词：桑树 碱性盐胁迫 叶绿素荧光 能量分配 

分 类 号：S601[农业科学—园艺学] Q945.1[生物学—植物学]