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Effects of Manganese Deficiency and Added Cerium on Photochemical Efficiency of Maize Chloroplasts

Author:
Qu, Chunxiang, Gong, Xiaolan, Liu, Chao, Hong, Mengmeng, Wang, Ling, Hong, Fashui
Source:
Biological trace element research 2012 v.146 no.1 pp. 94-100
ISSN:
0163-4984
Subject:
Ca2-transporting ATPase, Zea mays, cerium, chlorophyll, corn, electron transfer, fluorescence, manganese, nutrient deficiencies, photochemical reactions, photophosphorylation, photosystem II, reaction inhibition, thylakoids
Abstract:
The mechanism of the fact that manganese deprivation and cerium addition affect the photochemical efficiency of plants is unclear. In this study, we investigated the improvement by cerium of the damage of the photochemical function of maize chloroplasts under manganese-deprived stress. Chlorophyll fluorescence induction measurements showed that the ratio of variable to maximum fluorescence (Fv/Fm) underwent great decreases under manganese deficiency, which was attributed to the reduction of intrinsic quantum efficiency of the photosystem II units. The electron flow between the two photosystems, activities of Mg2+–ATPase and Ca2+–ATPase, and rate of photophosphorylation on the thylakoid membrane of maize chloroplasts were reduced significantly by exposure to manganese deprivation. Furthermore, the inhibition of cyclic photophosphorylation was more severe than non-cyclic photophosphorylation under manganese deficiency. However, added cerium could relieve the inhibition of the photochemical reaction caused by manganese deprivation in maize chloroplasts. It implied that manganese deprivation could disturb photochemical reaction of chloroplasts strongly, which could be improved by cerium addition.
Agid:
432202