摘要
以菜豆黄化幼苗作为试验材料,探讨了铅(Pb)或PEG(聚乙二醇)胁迫下交替呼吸途径在植物转绿过程中对叶绿素含量以及叶绿素荧光特性的影响,以阐明逆境胁迫下植物交替呼吸途径的生理学作用。结果显示:(1)与菜豆黄化幼苗正常转绿过程(对照)相比,Pb或PEG胁迫导致菜豆黄化幼苗的叶绿素含量积累延迟,使叶片PSⅡ潜在最大光化学量子效率(F_v/F_m)、光适应下最大光化学效率(F_v′/F_m′)、PSⅡ光适应下实际光化学效率(Y(Ⅱ))和光化学荧光猝灭系数(qP)显著下降,而非光化学猝灭系数(NPQ)则显著增加。(2)在菜豆黄化幼苗转绿过程中,Pb或PEG胁迫导致其交替呼吸途径容量较对照均显著上升。(3)Pb或PEG胁迫下,交替呼吸途径抑制剂[水杨基氧肟酸(SHAM,1mmol/L)]使菜豆黄化幼苗转绿过程中叶绿素含量、F_v/F_m、F_v′/F_m′、Y(Ⅱ)和qP进一步下降,NPQ却进一步增加,说明抑制交替呼吸途径会加剧Pb或PEG胁迫对PSⅡ反应中心活性的进一步抑制,使还原力积累加剧,造成热耗散进一步增加。研究表明,Pb或PEG胁迫均显著降低了菜豆黄化幼苗PSⅡ对光能的利用率,进而阻碍了菜豆黄化幼苗转绿进程;交替呼吸途径有助于在胁迫条件下缓解PSⅡ的过度还原,可能在一定程度上缓解了Pb或PEG胁迫对其转绿进程的阻碍作用。
By using etiolated bean(Phaseolus vulgaris)seedlings,the present work studied the effects of alternative respiratory pathway on chlorophyll content and chlorophyll fluorescence characteristics during greening of etiolated bean seedlings under Pb(lead)or PEG(polyethylene glycol)stresses,to elucidate the physiological role of alternate respiratory pathway of plants under environmental stress.The results showed that:(1)during greening of etiolated bean seedlings,Pb or PEG stress caused significant decreases of the chlorophyll content,Fv/Fm(the potential maximal photochemical efficiency of PSⅡ),Fv′/Fm′(the maximum quantum efficiency of PSⅡ photochemistry at illumination),Y(Ⅱ)(effective photochemi-cal quantum yield of PSⅡ photosynthetic),and qP(photochemical quenching coefficient),while Pb or PEG stresses increased the levels of NPQ(non-photochemical quenching),compared to the controls(greening of etiolated bean seedlings without environmental stress).(2)During greening of etiolated bean seedlings,the capacity of the alternative respiratory pathway was increased significantly,compared to the controls.(3)During greening of etiolated bean seedlings under Pb(lead)or PEG stresses,the leaves pretreated with salicylhydroxamic acid(the specific inhibitor of the alternative respiratory pathway,SHAM)exhibited lower levels of chlorophyll content,Fv/Fm,Fv′/Fm′,Y(Ⅱ)and qP,but higher levels of NPQ than the leaves without SHAM treatment.This indicate that inhibition of alternate respiratory pathways will aggravate the inhibition of PSⅡreaction center activity by Pb or PEG stress and further increase the accumulation of reducing power and increase of heat dissipation.These results suggested that,during greening of etiolated bean seedlings,Pb or PEG stress can significantly reduce the utilization of light energy by PSⅡ and hinder the greening process of etiolated bean seedlings,while the alternate respiratory pathway could alleviate the excessive reduction of PSⅡunder stress conditions,thus alleviating the inh
作者
芦丽娜
冉瑞兰
冯汉青
LU Li na;RAN Ruilan;FENG Hanqing(College of Life Sciences, Northwest Normal University, Lanzhou 730070, China)
出处
《西北植物学报》
CAS
CSCD
北大核心
2018年第11期2081-2089,共9页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家自然科学基金(31560070)
甘肃省高等学校科研项目(2015A-007)
甘肃省高校基本科研业务费项目
西北师范大学青年创新团队项目
甘肃省重点研发计划项目(18YF1NA051)
关键词
菜豆
PB胁迫
PEG胁迫
转绿
交替呼吸途径
叶绿素含量
叶绿素荧光
Phaseolus vulgaris
Pb stress
PEG stress
greening
alternative respiratory pathway
content of chlorophyll
chlorophyll fluorescence
