GROWTH AND MACRONUTRIENT CONTENTS OF FABA BEAN-PLANTS - EFFECTS OF SALINITY AND NITRATE NUTRITION

The effects of the interaction between sodium chloride, nitrate, and c oncentrations on growth and internal ion content of faba bean (Vicia f aba L.) plants were studied, to understand the relationship between th e above parameters and salt tolerance. Increased salinity substantiall y reduced the dry weight of roots and shoots and increased the root/sh oot biomass ratio. Additional nitrate-N considerably moderated the sal inity effects on these parameters. The promotive effects of nitrate-N were more pronounced on shoot dry weight. These results suggest that a n exogenous supply of nitrate-N would improve the vegetative growth of V. faba plants by moderating the suppresive effects of salinity. The evolution of the root and shoot content in potassium (K), sodium (Na), magnesium (Mg), calcium (Ca), and nitrogen (N) was monitored during v egetative growth. A high correspondence between total N and Ca content was found. The acquisition of Ca and K in response to salt and nitrat e was similar in shoots and roots, whereas Mg uptake showed notable di fferences in the two organs. In salt-affected plants, the roots were f ound to be high in accumulated Na while the shoots exhibited the lowes t Na concentration. Potassium accumulation was higher in the shoots. I n this way, there was an antagonistic effect between Na and K uptake. Analyses of the nutrient contents in plant organs have provided a data base on salt-tolerance mechanisms of V. faba plants.