ESTRESSE SALINO SOBRE A NODULAÇÃO EM FEIJÃO-CAUPI

Abstract

Soil salinity is a abiotic factor that can harmful of Rhizobium-legumes symbiosis, reducing plant nodulation and growth. The aim of this study was to evaluate the effect of saline stress on nodulation of cowpea inoculated with strain of Bradyrhizobium sp. The study was conduced out using plastic pots containing 5 kg of a Neossolo Quartzarênico typical órtico. The experimental design was randomized and the treatments consisted of five levels of salinity of irrigation water (0, 1, 2, 4 and 8 dS m-1). The seeds inoculation was made using inoculant containing Bradyrhizobium sp, strain BR 2001. The evaluations were made at 35 days after plant emergence, being determined the nodule number and dry mass and shoot mass. The analysis of variance showed that there was significant effect for salinity levels on all variables. The regression analysis showed negative linear and quadratic responses for the nodule number and dry mass, respectively. In relation to the dry mass was observed negative linear response. Nodulation of cowpea was reduced by the salinity levels showing a sensibility of symbiosis to saline stress.