Botanical and physiological parameters response of black bean (Phaseolus vulgaris L.) cultivars under increasing boron concentrations

Abstract

Argentina is one of the five leading exporters of common bean (Phaseolus vulgaris L.) worldwide. Although common bean has been characterized as sensitive to boron toxicity, its production is often subjected to high boron concentrations. The aim of this study was to provide detailed information on the impact of increasing boron concentrations (0.5–8.0 mg L−1) on germination, growth, and root anatomy of two black bean cultivars (Leales 24 and Uirapurú) frequently produced in Argentina. Standard germination assays and pot greenhouse experiments were conducted. Radicles obtained in germination assays were used to make cross sections, which were analyzed under the microscope to identify anatomical alterations. Increasing boron concentrations had no effect on germination variables. In contrast, most of the growth variables analyzed (height, leaf area, fresh and dry weight, and water content) showed a steady decrease for boron concentrations above 1.0 mg L−1. Tissue boron concentrations showed an increase when boron concentrations increased. At the microscopic level, there seemed to be a decreasing trend in xylem vessel diameter. Our results suggest that boron concentrations above 1.0 and 2.0 mg L−1 may cause considerable growth and yield decreases in Uirapurú and Leales 24, respectively, thus affecting Argentinian bean production. Additionally, our results suggest that Leales 24 is moderately sensitive to boron toxicity and is best adapted for production in areas with higher boron concentrations. These findings highlight the importance of evaluating boron concentrations in soils and irrigation water in agricultural areas, and selecting cultivars best adapted to local conditions as tools for obtaining higher yields.