In this study, eight transformed Solanum tuberosum L. plants, affected in their nitrate assimilatory pathway by the introduction of a tobacco nitrate reductase gene (Nia2), were cultivated in glasshouse conditions at INRA Ploudaniel (West Brittany, France). Two irrigation regimes were compared and plants were sampled at four stages of vegetation. Yield, tuber dry matter content, total nitrogen ...

The nitrate contents of various vegetables were analyzed by ion chromatography. It was shown that tahtsai, spinach, chingentsai and pakchoi contained more than 300 mg of nitrate per 100 g of edible portion. There was a significant difference in the nitrate content of leaf, stem and edible portion of chingentsai between summer and winter, and there was a significant difference in the nitrate con...

Present studies show that nitrate accumulation is the major factor influencing the water uptake by vegetables, but there is lack of knowledge on how the relationship between nitrate and water concentrations in different vegetable tissues. We determined nitrate accumulation and water content in vegetables of rape, Chinese cabbage, and spinach under different nitrogen levels (experiment I), 29 sp...

The effect of supplying either nitrate or ammonium on nitrate reductase activity (NRA) was investigated in Brassica napus seedlings. In roots, nitrate reductase activity (NRA) increased as a function of nitrate content in tissues and decreased when ammonium was the sole nitrogen source. Conversely, in the shoots (comprising the cotyledons and hypocotyl), NRA was shown to be independent of nitra...

Nitrate is an important component of the nitrogen cycle and is therefore present in all plants. However, excessive nitrogen fertilization results in a high nitrate content in vegetables, which is unhealthy for humans. Understanding the spatial distribution of nitrate in leaves is beneficial for improving nitrogen assimilation efficiency and reducing its content in vegetables. In this study, nea...

Experiments were conducted to determine whether the nitrate flux to the leaves or the nitrate content of the leaves regulated the nitrate reductase activity (NRA) in leaves of intact maize (Zea mays L.) seedlings having low water potentials (psi(w)) when other environmental and endogenous factors were constant. In seedlings that were desiccated slowly, the nitrate flux, leaf nitrate content, an...