A nitrate reductase inactivating factor was found in extracts of leaf blades, leaf sheaths, and roots of rice seedlings. The factor was nondialyzable, precipitable with (NH4)2SO4, and heat labile. The factor from rice roots inactivated NADH nitrate reductase, FMNH2 nitrate reductase, and NADH cytochrome c reductase from rice shoots, but had no effect on the activities of NADH diaphorase and nitrite reductase. The factors from rice shoots, rice roots, and maize roots inactivated NADH nitrate reductase prepared from cultured rice cells. The factor from cultured rice cells also inactivated rice shoot NADH nitrate reductase.The activity of the inactivating factor showed a diurnal change in shoots of rice seedlings grown with NO3- medium, although the fluctuation was not large compared to that of NADH nitrate reductase activity. When the seedlings were placed in darkness, the activity of the factor did not change during 20 hr with NO3- medium. However, the activity of the factor fluctuated with NO3- -free medium in light; its activity started to increase at the 8th hour after transfer. NADH nitrate reductase activity from rice shoots declined rapidly during the first 8 hr and gradually thereafter in both types of culture.
|ジャーナル||Plant and Cell Physiology|
|出版ステータス||Published - 1978 4月 1|
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