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R. Nakano H. Ishida M. Kobayashi A. Makino & T. Mae 《Plant biology (Stuttgart, Germany)》2010,12(1):35-45
During physiological stress, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) degradation is accelerated, which is considered to be one of the key factors responsible for photosynthetic decline. A recent study has shown that the large subunit (RbcL) of Rubisco is directly fragmented by hydroxyl radicals in Cucumis sativus leaves under chilling-light conditions. In the present study, we investigated biochemical aspects associated with this in vivo RbcL fragmentation by reactive oxygen species. RbcL fragmentation was observed in C. sativus and Phaseolus vulgaris , but not in Solanum lycopersicum , Glycine max , Oryza sativa , Triticum aestivum , Spinacia oleracea or Arabidopsis thaliana . In C. sativus and P. vulgaris , RbcL fragmentation followed the fragmentation of PsaB, while in the other species, PsaB fragmentation did not occur. In C. sativus and P. vulgaris , the activities of antioxidant enzymes decreased dramatically under chilling-light conditions, and the proportion of uncarbamylated Rubisco increased. These data suggest that in vivo RbcL fragmentation under chilling-light conditions is associated with a combination of events, namely, inactivation of antioxidant enzymes, destruction of photosystem I and an increase of uncarbamylated Rubisco, which can produce hydroxyl radicals via the Fenton reaction at the catalytic site of RbcL. 相似文献
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Cheng-Wei Yang Yi-Zhu Chen Chang-Lian Peng Duan Jun Gui-Zhu Lin 《Acta Physiologiae Plantarum》2001,23(4):391-398
The daily changes in the behavior of xanthophyll cycle and antioxidant systems in flag leaves of superhigh-yield hybrid rice
were investigated in relation to various developing stages. Dark-adapted Fv/Fm decreased with the increasing incident light
intensity on leaf surface in the morning and then minimized at midday; Deepoxidation State showed an opposed daily pattern
to Fv/Fm at different developing stage. As compared with increased deepoxidation state maximum value, the relative content
of xanthophyll cycle pigments remained almost constant during development. The daily changes in activities of superoxide dismutase,
ascorbate-peroxidase and glutathione reductase and the content of ascorbate and glutathione displayed a similar pattern, where
they increased from 8:00 and reached maximum at midday, however, a lower daily fluctuation of superoxide dismutase activity
was observed in senescent leaves. The enhanced contribution of xanthophyll cycle and Mehler-ascorbate peroxidase reaction
to photoprotection in old leaves could be partially due to the altered leaf posture. In conclusion, daily changes of xanthophyll
cycle and antioxidant systems in leaves of rice at various developing stages were dependent on leaf age, leaf angle and intensity
of solar irridiance. 相似文献
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