Resumo

MELONI, D. A.; SILVA, D. M.  e  BOLZON, G.. Effects of calcium addition on the physiology of vinal (Prosopis ruscifolia G.) seedlings under saline stress. Quebracho (Santiago del Estero) [online]. 2015, vol.23, n.1, pp.8-9. ISSN 0328-0543.

Vinal (Prosopis ruscifolia G.) is a highly saline stress-tolerant species, native to the Western Chaco Phytogeographic Region. The hypothesis that Ca+2 addition mitigates growth inhibition of saline stressed vinal seedlings using NaCl was tested in this study. The objective was to determine the effect of such addition on the growth of vinal seedlings under NaCl saline stress as well as its action mechanism. The seedlings were cultivated in a 25% Hoagland water solution, with the addition of 0.4 mol L-1 of NaCl, supplemented or not with 5 mmol L-1 of CaSO4. Dry matter, mineral composition, as well as nitrate reductase and glutamine synthetase activities were determined. An entirely randomized experimental design with five repetitions was utilized and the results were analyzed using ANOVA and Duncan's Test. The results indicate that calcium supplement alleviates growth inhibition caused by saline stress in Prosopis ruscifolia seedlings. Such a response is partially due to the increased concentrations of K+, Ca+2 and Mg+2 and the lowered concentration of Na+ in both leaves and roots. It can also be attributed to the reversion of the inhibitory effect of NaCl on the metabolism of N due to an increase in both the NO3- concentration and the activities of the enzymes nitrate reductase and glutamine synthetase.

Palavras-chave : salinity; mineral nutrition; nitrate reductase; glutamine synthetase.

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