Seeds from eight different maize genotypes (BR3123, BR5004, BR5011, BR5026, BR5033, CMS50, D766 and ICI8447) were sown in vermiculite, and after germination they were transplanted into nutrient solution or nutrient solution containing 100 mmol.L -1 of NaCl and placed in a greenhouse. During the experimental period plant growth (dry matter, shoot to root dry mass ratio, leaf area, relative growth rate, and net assimilation rate), leaf temperature, stomatal conductance, transpiration, predawn water potential, sodium, potassium, soluble amino acids and soluble carbohydrate contents were determined in both control and salt stressed plants of all genotypes studied. Salt stress reduced plant growth of all genotypes but the genotypes BR5033 and BR5011 were characterized as the most salt-tolerant and salt-sensitive, respectively. Stomatal response of the salt-tolerant genotype was not affected by salinity. Among the studied parameters, shoot to root dry mass ratio, leaf sodium content and leaf soluble organic solute content showed no relation with salt tolerance, i.e., they could not be considered as good morpho-physiological markers for maize salt tolerance. In contrast, sodium and soluble organic solutes accumulation in the roots as a result of salt stress appeared to play an important role in the acclimation to salt stress of the maize genotypes studied, suggesting that they could be used as physiological markers during the screening for salt tolerance.Keywords: growth analysis; osmoregulation; salinity; transpiration; Zea mays, water relations;.Efeito do estresse salino sobre o crescimento, resposta estomática e acúmulo de solutos em diferentes genótipos de milho: Sementes de oito genótipos de milho (BR3123, BR5004, BR5011, BR5026, BR5033, CMS50, D766 e ICI8447) foram semeadas em vermiculita e, após a germinação, transplantadas para vasos contendo solução nutritiva ou solução nutritiva com 100 mmol.L -1 de NaCl, em casa de vegetação. Durante o período experimental avaliaram-se, em plantas de todos os genótipos, sob condições de controle e estresse salino, os seguintes parâmetros: crescimento (matéria seca, relação de matéria seca parte aérea/raiz, área foliar, taxa de crescimento relativo e taxa de assimilação líquida), temperatura foliar, condutância estomática, transpiração, potencial hídrico antemanhã e teores de sódio, potássio, aminoácidos solúveis e carboidratos solúveis. O estresse salino reduziu o crescimento das plantas de todos os genótipos, sendo o BR5033 e o BR5011 caracterizados como tolerante e sensível ao estresse salino respectivamente. A resposta estomática do genótipo tolerante não foi influenciada pela salinidade. Entre os parâmetros estudados, a relação de matéria seca parte aérea/raiz e os teores de sódio e de solutos orgânicos nas folhas não mostraram relação com a tolerância à salinidade, isto é, não foram considerados bons marcadores morfo-fisiológicos para a tolerância à salinidade em milho. Em contraste, os teores de sódio e de solutos orgânicos nas raízes mostraram desempenhar um important...

Pitiuba cowpea (Vigna unguiculata (L.) Walp.) plants were grown in nutrient solution and kept in a greenhouse up to pre-flowering stage. They were subjected to four different treatments: nutrient solution; nutrient solution containing 75 mmol.L-1 NaCl; nutrient solution containing 75 mmol.L-1 NaCl and 5 mmol.L-1 CaCl2; and nutrient solution containing 75 mmol.L-1 NaCl and 10 mmol.L-1 CaCl2. Salt stress strongly inhibited plant growth, caused a disturbance in plant-water balance, and increased the total content of inorganic solutes in the different plant parts, due mainly to accumulation of Na+ and Cl-. It also increased leaf and root soluble carbohydrates, reduced soluble amino nitrogen both in root tips and in the youngest trifoliate leaves, and reduced proline levels in root tips. Although the addition of CaCl2 to the root environment of salt stressed plants caused a reduction in Na+ content, specially in roots, it did not ameliorate the salt stress effects on plant-water relations and growth. Therefore, the results obtained do not support the hypothesis that supplemental calcium would ameliorate the inhibitory effects of NaCl-stress.