Exogenous ascorbic acid scarcely ameliorates inhibition of photosynthesis in rice leaves by O3
2017
Kobayakawa, H. (Meiji University, Kawasaki (Japan). School of Agriculture) | Imai, K.
The role of ascorbic acid on acute O3-induced inhibition of photosynthesis in solution-cultured paddy rice was evaluated. As pre-treatment, ascorbic acid (0, 5, and 10 mM) was added to the culture solution for 5 d before 5 h of O3 exposure (0, .1, and .3 cubic cm /cubic m O3) during daytime. O3 decreased photosynthesis-related parameters, total ascorbic acid content, and the redox state (RDS) of ascorbic acid. Ascorbic acid treatment enhanced the total ascorbic acid contents and its RDS level of rice leaves, but scarcely ameliorated O3-induced inhibition of photosynthesis-related parameters. Inhibition of net photosynthetic rate (Psub(N))sup(3) by O3 was slightly ameliorated by exogenous ascorbic acid only at 1 d after O3 exposure. These results indicate that ascorbic acid is a component of protection from O3 injury but has a marginal role in the acute inhibition of Psub(N) by O3 in rice leaves.
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