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As special maize with more than 6% oil concentration in the grain, high-oil maize has received increased interest recently. To date, little is known about the expressions of genes involved in fatty acid metabolism of high-oil maize. Stearoyl-acyl carrier protein desaturase (SAD) is a key enzyme that converts stearic acid to oleic acid. In this study, two-dimensional electrophoresis, gas chromatography, and real-time PCR were used to determine the expressions of SAD at three seed development stages in high-oil and normal maize inbred lines. SAD was significantly more abundantly expressed in high-oil maize than in normal maize, not only at the protein and mRNA levels, but also at the product level. These results suggested that a high expression of SAD may play an important role in increasing oil concentration in high-oil maize. [ABSTRACT FROM AUTHOR]

The effects of NaCl stress on the activity of antioxidant enzymes, lipid peroxidation, cell membrane stability, net photosynthetic rate, gas-exchange, and chlorophyll content were investigated in two Jerusalem artichoke cultivars, Dafeng (salt-tolerant) and Wuxi (salt-sensitive), grown under control (nutrient solution) or salt stress (nutrient solution containing 75, 150, and 225 mM NaCl) conditions for 7 days. In leaves of salt-tolerant cv. Dafeng, superoxide dismutase (EC 1.15.1.1), peroxidase (EC 1.11.1.7), and catalase (EC 1.11.1.6) activities significantly increased as compared to the controls, whereas no significant change was observed in cv. Wuxi. Lipid peroxidation and cell membrane injury were enhanced in both cultivars. Net photosynthesis and stomatal conductance decreased in response to salt stress, but cv. Dafeng showed a smaller reduction in photosynthesis than cv. Wuxi. The results indicated that stomatal aperture limited leaf photosynthetic capacity in the NaCl-treated plants of both cultivars. However, significant reduction in the leaf chlorophyll content due to NaCl stress was observed only in cv. Wuxi. These results suggested that salt-tolerant Jerusalem artichoke varieties may have a better protection against reactive oxygen species, at least in part, by increasing the activity of antioxidant enzymes under salt stress. [ABSTRACT FROM AUTHOR]