Sodium chloride stress during early growth stages altered physiological and growth characteristics of rice
ABSTRACT The salt stress affects plant growth and physiological characteristics during early growth stages in rice (Oryza sativa L.) The objective of this study was to examine the influence of salt stress on rice growth during early stages and to find out their salt tolerance levels. A pot culture experiment was conducted in rice cropping season 2016, with completely randomized design (CRD) and three replicates. The treatments were two rice cultivars, 'Liangyoupeijiu' (LYP9) and 'Nipponbare' (NPBA) with four salt stress levels 0 (control, CK), 1.5 (low salt stress, LS), 4.5 (medium salt stress, MS), and 7.5 g (heavy salt stress, HS) NaCl kg-1 soil at different growth stages with six seedlings per pot. About 15 parameters were recorded and most of the treatments were significantly different (P < 0.05) from each other. The results showed that salt stress reduced seed emergence characteristics of the rice. It also decreased photosynthetic parameters, growth characteristics including DM, and seedling height reduction increased at early seedling and maximum tillering stage in both rice cultivars but this disaster is less in 'LYP9' than 'NPBA'. On the basis of DM reduction, 'LYP9' was categorized as moderately susceptible (MS) and susceptible (S) at HS during early growth stage, and 'NPBA' was categorized as sensitive to the HS stress level. The result suggested that 'LYP9' showed somehow resistance under salt stress than 'NPBA'. This study will help us to provide new ideas for improving the high yielding rice cultivar (LYP9) to salt tolerance by genetic modification and cultivation techniques.