Initial development in vitro of gliricidia in different levels of salinity

Abstract

The salinity is a common process in semiarid regions of Brazil, caused mainly for anthropogenic action as inadequate irrigation management and/or due to rainfall deficit relative to evapotranspiration. The accumulation of salts in the superficial layers of soil affect the plant development, resulting an economic and environmental problems, like lower crop yields and land degradation and abandonment. Therefore, the agroforestry systems was indicated to recover these areas and, the gliricidia is one species indicated for compose this systems. There are few works related with salinity tolerance of this species. The objective of this study was to evaluate the in vitro germination and initial development of gliricidia  cultivated at different levels of salt stress. Seeds was inoculated in cultured medium consisted of MS salts and different concentrations of sodium chloride (0, 30, 60, 90 e 120 mM). After 30 and 60 days of in vitro culture were evaluated the percentage of seed germination and  normal plantlets, shoot lenght and plantlet viability. The longer exposure of seeds to salt stress promoted the greatest results for all variables analyzed, except for viability. Occurred reduction of 5% in germination of the seeds inoculated in a culture medium supplemented with the highest concentration of  NaCl compared to control. However the increase of NaCl concentration promoted a decrease in percentage of normal seedlings, suggesting the gliricidia is sensitive to salt stress during initial development in vitro.