光照对紫叶风箱果叶色恢复及光系统Ⅱ的影响

Effects of light on leaf color restoration and photosystems Ⅱ of Physocarpus opulifolius 'Summer Wine'

为阐明光照对紫叶风箱果叶色恢复及光系统Ⅱ(PSⅡ)的影响,以3年生紫叶风箱果(Physocarpus opulifolius‘Summer Wine’)为试材,先遮荫使其叶色变为绿色,再进行全光照处理。结果显示:紫叶风箱果叶色在光照处理后迅速恢复为红色;叶绿素含量急剧升高,在处理2d达到最大值,比光照前增加了112.88%,达到极显著差异水平(P<0.01);花色素苷含量及其与叶绿素总量的比值从处理2d起极显著增加,分别比处理前增加了6.20,2.38倍;初始荧光(Fo)随处理时间的延长呈现"先升高后降低"的趋势,最大荧光(Fm)、PSⅡ最大光化学效率(Fv/Fm)则逐渐下降;光照处理后单位反应中心吸收的能量(ABS/RC)增大,单位反应中心用于热耗散的能量(DIo/RC)显著增高,表明PSⅡ反应中心将过剩的光能以热耗散的形式散发出来。综合分析可得,充足的光照更有利于紫叶风箱果叶片呈色,并不会对其PSⅡ造成长期影响。

To study the effect of light on leaf color restoration and photosystems Ⅱ,the threeyear-old Physocarpus opulifolius‘Summer Wine＇was used as the material in the experiment,and the leaves of,‘Summer Wine＇were first shasded till turning green,and then exposed to full light.The results indicated that：the leaf color of this plant rapidly restored to red after the light treatment;the content of chlorophyll increased sharply and reached greatest in the treatment of the 2nd day,which significantly increased by 112.8% compared with the pretreatment.The content of anthocyanin and the rate of anthocyanin/chlorophyll increased significantly in second day,which was 6.20 and 2.38 times higher than pre-treatment.With the treatment time prolonged,the initial fluorescence intensity（Fo）showed a trend of＂increasing first and then decreasing＂,while the maximal fluorescence intensity（Fm）and the maximal photochemical efficiency（Fv/Fm）decreased gradually.After the light treatment,the absorption flux per reaction center（ABS/RC）increased and the dissipated energy flux per reaction center（DIo/RC）increased significantly,which indicated that the excess light energy in the PSⅡ reaction center is distributed in the form of heat dissipation.It is considered that full light condi-tion is better for leaves coloration and does not cause long-term effects on its PSⅡ.