Effects of NaCl on Germination and Seedling Growth in Macrotyloma uniflorum and Vigna mungo

Abstract

Among abiotic stresses, drought and salinity are two major determinants due to high magnitude of their impact and wide occurrence. Salinity considerably limits the productivity of crops and thus, considered as the most destructive abiotic factor. In the present study, response of Macrotyloma uniflorum and Vigna mungo to salt (NaCl) stress imposed at germination and seedling growth stages was investigated. The aim of the study was identify the physiological and morphological responses of selected leguminous crop. Seeds were obtained from the healthy plants, surface sterilized and placed under six salt stress levels (0, 4, 8, 12, 16, 20 dsm-1). Complete randomized design with three replicates was used for this experiment and the experiments were conducted during the year 2015 in the glasshouse of Department of Botany, DSB, Campus, Kumaun University, Nainital. In comparison to Macrotyloma uniflorum (77%), higher germination percentage was observed in Vigna mungo (99%) at all salinity levels. In both the species, germination percentage and seedling growth decreased with the increase in salinity stress. Though Vigna mungo showed higher values for root (0.17 g) and shoot dry mass (0.27 g) the dry weight percentage reduction was higher in this species as compared to Macrotyloma uniflorum. Decrease in biomass of seedling with increasing salt stress indicated that the stress not only affected germination but also the growth of seedlings, which indicates that the synthetic ability of seed and biomass of the seedlings was also affected. Seed vigor index declined with the increase in salt concentrations. Outcomes from the study could be helpful in understanding the plant’s nature against different levels of salt stress and that could be economically exploited by various able agencies. At each salinity level, M. uniflorum showed higher salt tolerance index as compared to V. mungo so it can be cultivated in fields with salty soil.