Effects of hydric stress on the biological nitrogen fixation in acacia cyanophylla lindl

Water stress was applied to the plant after a convenient watering relatively long period. the following suspension imposed brutally severe conditions. After the second day following the installation of water stress, the apparent signs of disruption of the physiological processes (leaf water potential, plant growth and nitrogen uptake) begin to appear. It is necessary to note that the experimentation was carried out on seedlings, in conditions completely different from those in natural conditions. The obtained results show that water stress induced a considerable viable nodule rate decrease. the symbiotic nitrogen fixation, as estimated by isotopic N dilution showed that the symbiotic fixation of Nitrogen 2 by acacia cyanophylla is strongly reduced as of the third day of water stress installation. It has been showed that the symbiotically fixed nitrogen remains for the most part confined in the roots (author)