Salt sensitivity in chickpea (Cicer arietinumL.): ions in reproductive tissues and yield components in contrasting genotypes

The reproductive phase in chickpea (Cicer arietinumL.) is affected by salinity, but little is known about the underlying cause. We investigated whether high concentrations of Na+ and Cl- in the reproductive structures influence reproductive processes. Chickpea genotypes contrasting in tolerance were subjected to 0, 35 or 50mm NaCl applied to soil in pots. Flower production and abortion, pod number, percentage of empty pods, seed number and size were evaluated. The concentrations of Na+, K+ and Cl- were measured in various plant tissues and, using X-ray microanalysis, in specific cells of developing reproductive structures. Genotypic variation in reproductive success measured as seed yield in saline conditions was associated with better maintenance of flower production and higher numbers of filled pods (and thus seed number), whereas seed size decreased in all genotypes. Despite the variation in reproductive success, the accumulation of Na+ and Cl- in the early reproductive tissues of developing pods did not differ between a tolerant (Genesis836) and a sensitive (Rupali) genotype. Similarly, salinity tolerance was not associated with the accumulation of salt ions in leaves at the time of reproduction or in seeds at maturity. We studied whether the adverse effects of salinity on reproductive processes in chickpea are associated with ion accumulation in reproductive tissues. Quantitative X-ray microanalysis was used to evaluate the concentrations of Na, K and Cl in specific cells of developing reproductive organs of two genotypes of contrasting salt tolerance. Despite large genotypic differences for seed yield of plants in saline soil, Na, K and Cl concentrations in developing ovules and pod walls were similar for the two genotypes. Although Na concentrations had increased in these early reproductive tissues the concentrations were relatively low. Na had also increased in mature seeds, but this did not impact their subsequent germination.