Acúmulo de solutos orgânicos e inorgânicos em cultivares de feijão-de-corda submetidos à estresse salino

Abstract

Salt stress is one of the limitations imposed crops, and consequently has led to the reduction of its growth and production. Considering that this condition is caused by inadequate water management and irrigation techniques used in agriculture. The quality of water for irrigation purposes, is an aspect that can be taken into account for the major land degradation problem by salinization. The arable crops, develop mechanisms of resistance and tolerance to these processes deemed offensive to its best development. The vigna beans, grown mainly in arid and semi-arid regions, has demonstrated an adaptation to saline environments without causing major damage. The accumulation of compatible solutes by plants, is a typical example of a mechanism of resistance to abiotic stress conditions. Thus, the aim, with this study was to evaluate and observe the effects of irrigation water with different salinity levels, through responses of the accumulation of organic and inorganic solutes in the dry matter of the leaves of plants in two of vigna bean cultivars. The experiment was conducted at an open vessels in the experimental area of Agrometereológica Station of the Federal University of Ceará, Fortaleza, Ceará. We used the statistical design of randomized blocks with split plots (split-plot), where salinity levels were distributed in installments while the cultivars in the subplots. Salinity levels corresponded to: S1, salinity level of 0.7 dS m-1 (water from a groundwater well, belonging to the weather station at the Federal University of Ceará); S2 salinity level of 1.5 dS m-1; S3 salinity of 3.0 dS m-1; S4 salinity of 4.5 dS m-1; S5, salt level of 6.0 dS m-1. The cultivars were Epace 10 and BRS Itaim. The variables evaluated were: organic solutes content (total soluble carbohydrates, N - aminossolúveis and free proline) and inorganic (potassium, sodium and chloride). The organic solutes (total soluble carbohydrates, N - aminossolúveis and free proline) accumulate significantly in the leaves of plants studied cultivars. Similar results were found when assessed the levels of inorganic solutes (sodium and chloride), where the accumulation of these solutes in the leaves of plants of the vigna bean cultivars showed significant responses. Potassium solute showed opposite results, as it increased the salinity levels of irrigation water, the concentration of this ion in plant leaves decreased. Among the cultivars, cultivating Epace 10 showed the greatest accumulation in all variables analyzed.