Protective mechanism in photoinhibition of photosynthesis in Citrus unshiu leaves

Abstract

Abstract: By using a portable PAM-2000 fluorometer and a spectrophotometer (722 Model), the diurnal variation in main chlorophyll fluorescence parameters such as initial fluorescence (F₀), maximal fluorescence (Fm), ratio of variable fluorescence to maximal fluorescence (Fv/Fm), non-photochemical quenching (qN), fast-phase (qN_f) and slow-phase (qNs) of non-photochemical quenching, electron transport rate (ETR), and relative content of xeaxanthin in Citrus unshiu leaves were observed on fine days. The results showed that ETR, qN, qN_f, qN_s and relative content of xeaxanthin increased with increasing light intensity, but Fm, F₀, photo-chemical efficiency of PSÒ(Fv/Fm) decreased. After treated by DTT, qN_s was much lower, but F₀ was much higher than control. These results indicated that xanthophyll cycle and △pH existed,and played an important protective role against photo-damage to the photosynthetic apparatus in Citrus unshiu leaves during diurnal variation of photosynthetic efficiency.

Key words: Citrus unshiu, Photoinhibition, Chlorophyll fluorescence, Xanthophyll cycle, landscape planning, low impact development (LID), low impact development technology, runoff control rate, coastal industrial park

CLC Number:

Q945.11

SONG Lili, GUO Yanping, XU Kai, ZHANG Liangcheng. Protective mechanism in photoinhibition of photosynthesis in Citrus unshiu leaves[J]. Chinese Journal of Applied Ecology, 2003, (1): 47-50.

References

[1] Adams Ó WW ＆ Demmig-Adams B.1992.Operation of the xanthophyll cycle in higher plants in response to diurnal changes in incident sunlight.Planta,186:390～398
[2] Baker NR.1991.A possible role for photosystem Ò.Environmental pertubations of photosynthesis.Physiol Plant, 81:563～570
[3] Bilger W ＆ Bjrkman O.1990.Role of the xanthophyll cycle in photoprotection elucidated by measurements of light-induced absorbance changes, fluorescence and photosynthesis in leaves of Hedera canariensis.Photosynth Res,25:173～185
[4] Bilger W, Bjrkman O ＆ Thayer SS.1989.Light-induced spectral absorbance changes in relation to photosynthesis and the epoxidation state of xanthophyll cycle components in cotton leaves.Plant Physiol,91:542～551
[5] Chen Z-H (陈志辉), Zhang L-C(张良诚).1994.Diurnal variation in photosynthetic efficiency of leaves in Satsuma Mandarin.Acta Phytophysiol Sin(植物生理学报),20(3):263～271(in Chinese)
[6] Demmig B, Winter K, Krüger A,et al.1987.Photoinhibition and zeaxanthin formation in intact leaves:A possible role of the xanthophyll cycle in the dissipation of excess light energy.Plant Physiol, 84:218～224
[7] Demmig-Adams B ＆ Adams Ó WW.1996.Xanthophyll cycle and light stress in nature:uniform response to excess direct sunlight among higher plant species.Planta,198:460～470
[8] Demmig-Adams B ＆ Adams Ó WW.1992.Photoprotection and other responses of plants to high light stress.Ann Rev Plant Physiol Plant Mol Biol,43:599～626
[9] Demmig-Adams B ＆ Winter K.1988.Characterization of three components of non-photochemical fluorescence quenching and their response to photoinhibition.Aust J Plant Physiol, 15:163～177
[10] Demmig-Adams B, Adams Ó WW, Baker DH,et al.1996.Using chlorophyll fluorescence to assess the fraction of absorbed light allocated to thermal dissipation of excess excitation.Physiol Plant,98:253～264
[11] Dodd IC, Critchley C, Woodall GS,et al.1998.Photoinhibition in differently colored juvenile leaves of Syzygium species.J Exper Bot,49(325):1437～1445
[12] Genty B, Briantais JM, Baker NR.1989.The relationship between the quantum yield of photosynthetic electron transport and quenching of chlorophyll fluorescence.Biochem Biophys Acta, 990:87～92
[13] Guo Y-P(郭延平), Zhan L-C(张良诚), Hong S-S(洪双松),et al.1999.Photoinhibition of photosynthesis in Satsuma Mandarin (Citrus unshiu Marc.).Acta Hortic Sin(园艺学报), 26(5):281～286.(in Chinese)
[14] Hong Shuang-Song, Xu Da-Quan.1999.Light-induced increase in initial chlorophyll fluorescence F₀ level and the reversible inactivation of PSⅡreactivation centers in soybean leaves.Photosynth Res,61:269～280
[15] Hong T(洪涛), Xu D-Q (许大全).1999.Non-photochemical quenching of chlorophyll fluorescence in soybean and sweet viburnum leaves.Acta Phytophysiol Sin(植物生理学报), 25(1):15～21 (in Chinese)
[16] Horton P, Hague A.1988.Studies on the induction of chlorophyll fluorescence in isolated barley protoplasts Ô.Resolution of non-photochemical quenching.Biochem Biophys Acta, 932:107～115
[17] Horton P, Ruban A, Walters RG.1994.Regulation of light havesting in green plants:indication by non-photochemical quenching of chlorophyll fluorescence.Plant Physiol, 106:415～423
[18] Powles SB.1984.Photoinhibition of photosynthesis induced by visible light.Annu Rev Plant Physiol, 35:15～44
[19] Quick WP, Stitt M.1989.An examination of factors contributing to non-photochemical quenching of chlorophyll fluorescence in barley leaves.Biochem Biophys Acta,977:287～296
[20] Xu D-Q(许大全), Xu B-J(徐宝基), Shen Y-G(沈允钢).1990.Diurnal variation of photosynthetic efficiency in C3 plants.Acta Phytophysiol Sin(植物生理学报),16:1～5 (in Chinese)