Water deficiency during bean seed germination induced by different osmotic solutions

Abstract

Snap beans are sensitive to water stress, due to their low ability to recover after water deficit and to their poor developed root system. This work was aimed to verify the effects of osmotic solutions CaCl₂, MgCl₂ and Mannitol in the potential of 0; -0.3; -0.6; -0,9 MPa during snap bean seed germination. Germination, first counting of germination, vigour classification, length and dry mass of seedlings shoot and roots were evaluated. CaCl₂

allowed maximum germination at -0.55 MPa but mannitol and MgCl₂ did not promote any changes in germination. Water deficit lowered the germination velocity for any osmotic solution used. Amid the developmental parameters, root length was the most sensible, showing that roots were less developed in CaCl₂ than in manitol. So, Ca²⁺ and Mg²⁺ worked as signaling ions, inducing a seedling tolerance to water deficit and the roots were less developed when exposed to CaCl₂ e MgCl₂ in relation to manitol.