The Relationship Of Anthocyanin And Photosynthetic Apparatus In Leaves Of Afforestation Plants

Anthocyanins are water-soluble pigments found in all plant tissues. Anthocyanins often appear transiently at specific developmental stages and may be induced by a number of environmental factors including visible and low temperature. The subsequent production of anthocyanins in leaf tissues may allow the plant to develop resistance to some stresses. This study focused on its photoportective effect on leaf tissues. Taking Ocimum basilicum ’purple ruffles’, Ocimun gratissimum L., Syringa oblata Lindl and Prunus cerasifera Ehrhart f. atropurprea Jacq as material, the relationship of leaf anthocyanin and energy distribution under low temperature, light intensity and leaf expansion stage were investigated to reveal the physiological role and significance of anthocyanin on plant leaves under stress.1. Taking Ocimum basilicum ’purple ruffles’ and Ocimun gratissimum L. seedlings as test material, the effects of anthocyanin on chlorophyll fluorescence and energy distribution in leaves of Ocimum basilicum L. seedlings under different lights were investigated, which were treated in dark, low temperature of4℃for3hours. The results showed that these parameters of fluorescence in leaves of Ocimun gratissimum L. seedlings with low temperature pretreatment were essentially unchanged, which was indicated that weak light was beneficial to recovering of Ocimum basilicum L. seedlings after the release of low er temperature. However, weak light led to the decrease of quantum yield of photochemistry (YPSⅡ) in leaves of Ocimum basilicum ’purple ruffles’ seedlings and the increase of quantum yield of trans-thylakoid pH gradient (ΔpH-) and xanthophyll-regulated thermal energy dissipation (YNPQ), which prolonged recovery time in leaves of Ocimum basilicum ’purple ruffles’seedlings after the release of low er temperature. These parameters of fluorescence in leaves of Ocimun gratissimum L. seedlings were diminished under high light. The photoinhibition occurred in leaves of Ocimun gratissimum L. seedlings but not in leaves of Ocimum basilicum ’purple ruffles’under high light, which was due to the effects of anthocyanin on light attenuation and filtration. The high light led to the dedrease of YPSⅡ and increase of quantum yield of thermal dissipation associated with the presence of non-functional PSⅡ(YNF) in leaves of Ocimun gratissimum L. seedlings with low temperature pretreatment. These leaves of Ocimun gratissimum L seedlings with low temperature pretreatment absorbed excess light energy, and increased the inactivation number of PSⅡ. This was not conducive to PSⅡ activity recovery. While high light resulted in the increase of TPSⅡ and the decrease of YNPQ in leaves of Ocimum basilicum ’purple ruffles’ seedlings with low temperature pretreatment. This further proved the role of anthocyanin in protecting leaves of Ocimum basilicum ’purple ruffles’seedlings from photoinhibitory damage.2. Taking Syringa oblata Lindl as test material, effects of changes in leaf anthocyanin on chlorophyll contents, chlorophyll fluorescence characteristics and excitation energy distribution in photosynthetic apparatus in leaves of S. oblata Lindl during leaf expansion were investigated. The results showed that anthocyanin contents in leaves of S. oblata Lindl were decreased gradually from leaf extension to leaf mature, chlorophyll contents in leaves were increased, anthocyanin and chlorophyll contents was a significant negative correlation, and capability of light capture and utilization were strengthened gradually with leaf anthocyanin contents, but the maximal PS Ⅱ photochemical efficiency (Fv/Fm) was no changed significantly. During leaf expansion, the percentage of excited energy of quantum yield of thermal dissipation assigned by light absorption of PS Ⅱ reaction center to non-functional PSⅡ(φNF) increased with descent of leaf anthocyanin contents, and ΦNF and quantum yield of xanthophyll-regulated thermal energy dissipation (ΦNPQ) was an obvious positive correlation. It concluded that anthocyanin in the leaves of S. oblata Lindl could increase the non-radiative energy dissipation which dependent on the Xanthophyll cycle in order to avoid growing leaves from damage of excess light energy.3. Anthocyanin contents and distribution of photosynthetic energy in leaves of Prunus cerasifera Ehrhart f. atropurprea Jacq seedlings under full illumination or different shading (shading25%, shading50%and shading75%) were investigated. The results indicated anthocyanin contents in leaves of Prunus cerasifera Ehrhart f. atropurprea Jacq seedlings were decreased on shading, but chlorophyll contents were increased. The initial fluorescence (Fo), maximum fluorescence (Fm) and non-photochemical quenching coefficient (qN) increased in leaves of Prunus cerasifera Ehrhart f. atropurprea Jacq seedlings with the enhanced shading, while actual photosynthetic II efficiency (Fv/Fm), photochemical quenching (qP) and electron transport rate (ETR) decreased. This showed a conclusion that the Prunus cerasifera Ehrhart f. atropurprea Jacq seedlings were light preferring plants, and should be planted under natural condition. The leaf photoresponse curve ofΦPSⅡ and ETR showed that the ΦPSⅡ decreased with the increase of light intensity, but ETR increased. Meanwhile, the proportion of the quantum yield of PSⅡ photochemistry (ΦPSⅡ) had an obvious negative correlation with the shading degree, but the quantum yield of xanthophyll-regulated thermal energy dissipation (ΦNPQ) and the quantum yield of thermal dissipation associated with the presence of non-functional PSⅡ (ΦNF) increased. The non-functional PSⅡ significantly increased as shading degree reached75%. The shading to regulate photosynthetic capacity by way of influencing leaves photosynthetic pigment and anthocyanin contents and distribution of photosynthetic energy and and then to improve adaptability of long-term weak light in Prunus cerasifera Ehrhart f. atropurprea Jacq seedlings.