CAJ | 학술논문

以自育苜蓿品种越冬之星为试验材料,利用叶绿素荧光技术,研究了苜蓿叶片PSⅡ和PSⅡ最大光能转化效率(Fv/Fm)的日变化及其光能分配特性.结果表明,苜蓿叶片Fv/Fm和实际光化学效率(φPSⅡ)的日变化均呈现"双峰"曲线,中午期间的PSⅡ功能下调,有明显的光抑制.在光合有效辐射(PAR)逐渐增强过程中,Fv/Fm和φPSⅡ降低,非光化学猝灭(NPQ)增加,激发能由PS Ⅰ向PSⅡ分配比例增加,说明引起苜蓿光抑制的原因除了NPQ之外,分配给PSⅡ能量增加后进一步促进PSⅡ可逆失活是非常重要的因素.PAR逐渐减小时,光抑制逐渐减缓,光化学效率恢复,这主要是由于NPQ减小,激发能分配不平衡性系数(β/α-1)下降,PSⅡ能量负荷减轻,失活的PSⅡ恢复活性的结果.
이자육목숙품충월동지성위시험재료,이용협록소형광기술,연구료목숙협편PSⅡ화PSⅡ최대광능전화효솔(Fv/Fm)적일변화급기광능분배특성.결과표명,목숙협편Fv/Fm화실제광화학효솔(φPSⅡ)적일변화균정현"쌍봉"곡선,중오기간적PSⅡ공능하조,유명현적광억제.재광합유효복사(PAR)축점증강과정중,Fv/Fm화φPSⅡ강저,비광화학졸멸(NPQ)증가,격발능유PS Ⅰ향PSⅡ분배비례증가,설명인기목숙광억제적원인제료NPQ지외,분배급PSⅡ능량증가후진일보촉진PSⅡ가역실활시비상중요적인소.PAR축점감소시,광억제축점감완,광화학효솔회복,저주요시유우NPQ감소,격발능분배불평형성계수(β/α-1)하강,PSⅡ능량부하감경,실활적PSⅡ회복활성적결과.
A study was conducted, using chlorophyll fluorescence technique and a local alfalfa variety Yuedongzhixing as experimental material, to investigate the diurnal changes of PS Ⅱ and maximum quantum efficiency of photosystem Ⅱ photochemistry(Fv/Fm) in alfalfa leaves. The data acquired in this study showed that the diurnal changes of Fv/Fm and actual photochemical efficiency of PS Ⅱ (φPS Ⅱ) were related to light intensity, the functional photosystem Ⅱ reaction centers were decreased to cause significant photoinhibition. With the increasing of photosynthetic actual irradiation (PAR)to simulate PAR diurnal change, and φPS Ⅱ decreased, nonphotochemical quenching (NPQ)increased, and the fraction of excited energy allocated to PS Ⅱ increased to enhance PS Ⅱ burden carrying excited energy. These results indicated that photoinhibition in alfalfa leaves were caused primarily by increasing of excited energy allocated to PS Ⅱ to enhance reversible inactivation of PS Ⅱ centers except NPQ increasing. With the decreasing of PAR,Fv/Fm and φPS Ⅱ increased, NPQ and unbalance index of excited energy allocated to PS Ⅱ and PS Ⅰ (β/α -1) declined respectively. This indicated that the recovery of PS Ⅱ photochemical efficiency was caused primarily by renewing PS Ⅱ activation owing to unloading the energy burden of PS Ⅱ.