Response of vicia faba [Brood bean] Plant to preplanting soil incorporation with different rates of topogard and enide herbicides

The effect of two common herbicides viz topogard SOWP a triazine and enide SOWP [amide family] on growth of the various parts of broad bean [Vicia faba] seedlings was investigated. Pre-emergence application of both herbicides resulted in stunted growth of shoot and root and decrease of the seedling dry matter, particularly with "enide". Necrosis and chlorosis appeared on the leaves of enide-treated seedlings only. Nitrate uptake and nitrate reductase activity [NRase] were markedly suppressed, specially in enide-treated seedlings. This suppression may be related to a disturbance of the NO3 transport system as well as to the inhibitory effect of the herbicide on enzyme synthesis. Treatment with these herbicides decreased the total carbohydrate and nitrogen contents of seedlings, presumably due to an inhibitory effect on photosynthesis and protein biosynthesis in Vicia faba seedlings

Changes in nitrate reductase activity of chlorella vulgaris grown on horse waste

The rate of absorption of various soluble organic-N fractions by Chlorella cells grown on 0.2% horse dung extract increased by increasing experimental period. This was accompanied by inhibition of nitrate reductase[NR] activity and decrease in the rate of nitrate disappearance. Transferring waste-precultured Chlorella cells to nitrogen-deficient medium resulted in a great depression of NR activity, while addition of NO[3]to the medium increased the activity. The main effect of the organic-N fraction of horse dung extract was on the NR activity rather than on NO[3] uptake or nitrate reductase synthesis in Chlorella cells

Influence of trace elements, tungsten and vanadium, on the in vivo nitrate reduction in azoola-anabaena symbiosis

Molybdenum [Mo] is an essential microelement for the induction of nitrate reductase in Azolla-plants. In Mofree cultures, tungsten [W] or vanadium [V] could not replace Mo. for nitrate reductase activity. Although- vanadium, up to a concentration of 0.01 ppm, enhanced the activity of nitrate reductase in Mo-containing cultures, tungsten showed an inhibitory effect. The suppression of nitrate reductase activity may, be related to the replacement of Mo co-factor or inhibition of the NADH-linked enzyme