Seed germination of paineira under water and salt stress

Multiple stresses promoted by a changeable environment can limit germination process, seedling emergence and survival. The objective of this work was to determine the effect of water and salt stresses on the viability and vigour of "paineira" seeds (Chorisia speciosa St. Hil.) and the maximal tolerance limits. Water stress was evaluated using mannitol and PEG 6000 solutions. Salt stress was evaluated using NaCl, KCl and CaCl, solutions. After coat punction, four replicates of 50 seeds for each treatment were submitted to germination on filter paper moistened with test solutions at different osmotic potential and kept at 27degreesC. The lowest tolerance limit to water stress was observed when PEG solutions were used. The maximal tolerance limit was between -0.6 and -0.7 MPa for PEG 6000 and between - 1.4 and - 1.6 MPa for mannitol solutions. The germination percentage decreased with the reduction of the osmotic potential of the environment, independently of the used salts. The same tolerance limits to different salts were observed between - 1.0 and - 1.2 MPa. Paineira may be considered a glycophyte with moderate tolerance to the salts NaCl, KCl and CaCl2.