Anthocyanin In Leaves Of Spiraea On PSⅡPhotochemical Activity And Their Difference Between Varieties

The research aimed to improve plant efficiency of photosynthesis under stress and ease light inhibition of leaf photosynthesis reaction center. This experiment studied the anthocyanin in the Spiraea leaf effect on photosynthetic PS II function under different stress by the chlorophyll fluorescence parameters and OJIP as the main reference index anthocyanin to discuss the impact on the process of photosynthesis energy absorption, distribution, conversion, electron transfer and protective effects of adversity on the photosynthetic apparatus by the anthocyanin. The main results were as follows:1. anthocyanin contents were lower in expanded leaves of three Spiraea than in expanding leaves, chlorophyll content and chlorophyll fluorescence parameters have no significant difference. However, chlorophyll content in expanding leaves of S.xbunmalba cv.Goldflame and S.xbunmalba cv.Goldmound were lower than that of S. pubescens, and anthocyanin contents were higher than that of S. pubescens expanding leaves. Meanwhile, minimal fluorescence (Fo), maximum fluorescence (Fm) and absorption flux per reaction center (ABS/RC) in young leaves of S.xbunmalba cv.Goldflame and S.×bunmalba cv.Goldmound was lower than that of S. pubescens, which indicated that anthocyanins could reduced the absorption of light in Spiraea leaves. Furthermore, the parameters of PS II photochemical efficiency (Fv/Fm), PS II potential activities (Fv/Fo), electron transport rate (ETR) and actual photochemical efficiency (ΦPpSⅡ) in expanding leaves of S.xbunmalba cv.Goldflame and S.xbunmalba cv.Goldmound were higher than that of S. pubescens respectively. It suggested that anthocyanins could changed the activity of PS II reactive center in leaves of S.xbunmalba cv.Goldflame and S.×bunmalba cv.Goldmound. However, the number of PS II reactive center, absorption flux per reaction center (ABS/RC), maximal trapped energy flux per reaction center (TRo/RC), electron transport flux per reaction center (ETo/RC) and dissipated energy flux per reaction center (DIo/RC) in expanding leaves of S. pubescens were significant higher than S.×bunmalba.cv.Goldflame and S.×bunmalba cv.Goldmound, while the proportion of inactivation of reactive center in S. pubescens young leaves was higher than others. Consequently, we have deduced the conclusion that anthocyanins not only changed the absorption of light energy in expanding leaves of S.xbunmalba cv.Goldflame and S.xbunmalba cv.Goldmound but also changed the electronic transfer and photosynthesis distribution of the energy, influenced the PS II function in expanding leaves of Spiraea.2. Salt stress make S.×bunmalba cv.Goldflame leaf chlorophyll content significantly decreased, the initial fluorescence F0rose, maximum fluorescence Fm and PS II reaction center the largest light energy conversion efficiency of Fv/Fm significantly decreased, Vj and Mo increased significantly and Sm declined, lowering the activity of the reaction center openness, photochemical quenching qp reduction and non-photochemical quenching qNP increased, indicating that salt stress damage the electron transport chain, reducing photochemical efficiency, inhibiting blades photosynthesis. The degree of inhibition by high anthocyanin content was significantly lower than the stretch leaves anthocyanin content less fully expanded leaves. Fv/Fm, Fq, Fm,ΦPSⅡ, qp, qNP parameters such as the magnitude of the change in stress also were less than fully expanded leaves. Description of anthocyanins to reduce the salt stress S.×bunmalba cv.Goldflame stretch chlorophyll decomposition protect the electron transport chain, improving the electron transfer rate, reduce salt stress on PS II reaction center damage on PS Ⅱ reaction centers play a protective effect, so that the blades extend PS II reaction centers remain relatively high activity under salt stress, increase the resistance to leaf adversity.3. Chlorophyll fluorescence kinetics of the fast phase (OJIP) as a probe to study the impact of drought stress in leaves of S.×bunmalba cv.Goldflame anthocyanin PS II functions. The results showed:under drought stress, S.xbunmalba cv.Goldflame proportion of fully expanded leaves of electronic energy transfer (ΦEo) arid section10day and arid first day compared to the drop of32.51%. Stretch leaves falling25.89percent, less than the magnitude of the change in fully expanded leaves; fully expanded leaves capture the energy unit reaction center (ETo/RC) for electron transfer in the first10day of drought leaves6.11%lower than the stretch, indicating higher anthocyanin content increased relative stretch leaves under drought stress activity of PS Ⅱ reaction center units, reaction centers can allocate more energy for electron transfer, reducing the amount of QA reduction, so that electron transfer efficiency increases, reducing the reaction center degradation and inactivation, and make active reaction center efficiency, thereby increasing the carbon assimilation produced by NADPH and ATP production, to ensure that the energy needs of S.×bunmalba cv.Goldflame, increased drought resistance S.×bunmalba cv.Goldflame leaves.