Abstract

MORALES GUEVARA, Donaldo et al. Salinity preconditioning effects on water relations, gas exchange and root hydraulic conductivity in tomato plants (Solanum lycopersicum L. cv. Amalia). cultrop [online]. 2012, vol.33, n.3, pp. 57-62. ISSN 0258-5936.

The present work was conducted with the objective of studying the behavior of growth, the net photosynthetic rate, stomatal conductance, hydraulic conductivity of roots and leaf water, osmotic and turgor potencials in seedlins of tomato plants submitted to progressive increase to NaCl in the medium, for this seedlins of tomato plants (Solanum lycopersicum L. Cv. Amalia) were submitted to seven different treatments: control (C) plants were maintained in nutrient solution without NaCl; adapted plants (PC) were submitted to progressive increase of 25 mM of NaCl each four days in nutritious solution, in the others treatments were submitted to 25, 50, 75, 100 and 125 mM of NaCl during all experimental period. The inhibition of dry mass accumulation in root system and stem was observed in non adapted plants, while the leaf dry mass and leaf area were affected in all treatments in relation to control plants. Saline stress decreased net photosynthetic rate, stomatal conductance and root hydraulic conductivity in non adapted plants, however, PC plants showed good osmotic adjustment, which enabled them to maintain leaf pressure potential, decreased leaf water potential and osmotic potential at full turgor while the biologic activity was appropriate.

Keywords : photosynthesis rate; stomatal conductance; leaf water potential; hydraulic conductivity; growth.

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