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Effects of Soil Salinity on Tocopherols, Tocotrienols, and γ‐Oryzanol Accumulation and their Relation to Oxidative Stress in Rice Plants
Author(s) -
Tung YuHsiang,
Ng LeanTeik
Publication year - 2016
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2015.10.0664
Subject(s) - salinity , malondialdehyde , antioxidant , catalase , superoxide dismutase , soil salinity , zoology , biology , food science , agronomy , peroxidase , horticulture , chemistry , botany , enzyme , biochemistry , ecology
Tocopherols (Toc), tocotrienols (T3), and γ‐oryzanol (GO) are major bioactive compounds of rice that have been known to possess various pharmacological properties. Understanding the stress effects on the accumulation of these compounds may aid in the improvement of rice grain quality. In this study, our aim was to examine the effects of soil salinity on Toc, T3 and GO contents, as well as their role in antioxidant status in rice plants. Four levels of salinity treatments with electrical conductivity values of 0, 2, 4, and 8 dS m −1 were conducted during the reproductive stage of rice (95 d after transplanting). Compared with the control, results showed that salinity treatments significantly increased the contents of total T3, α‐Toc, α‐T3, and γ‐T3 in the rice grains; however, there was no difference in the content of total Toc. Under high salinity (electrical conductivity value 8 dS m −1 ) conditions, GO concentration increased significantly in the grains while that of γ‐Toc decreased. Salinity treatments caused malondialdehyde content to increase in the rice straws, while H 2 O 2 level was not affected. Increasing salinity led to a significant decrease in ascorbate concentration in the rice straws and grains, and enhanced superoxide dismutase, ascorbate peroxidase, and catalase activities in the rice straws; however, the enzymatic antioxidant activities in the rice grains were lower as compared with the control group. This study suggests that moderate increases in soil salinity can enhance T3 and GO accumulation in the rice grains.