Root growth of a salt susceptible and a salt resistant rice (Oryza sativa L) during seedling establishment under NaCl salinity

Abstract

The salt susceptible rice (Oryza sativa L.) cv. Jaya and salt resistant cv. Damodar seed germination and seedling growth rates were studied in laboratory and field conditions. The effect of salinity on seed germination, shoot and root length, seedling vigour index (SVI) and increase in the root:shoot length ratio in the laboratory was relatively more in cv. Jaya than in cv. Damodar. The relative susceptibility to salinity was more in cv. Jaya than in cv. Damodar in the field also. However, their responses varied with growth period. The root:shoot length and fresh and dry weight ratios increased with salinity at 15 days in cv. Jaya. The root:shoot fresh and dry weight ratio decreased with salinity at 15 days in cv. Damodar. However, the root:shoot fresh weight ratio decreased with salinity at 25 days in the susceptible cv. Jaya. The root and shoot length fresh and dry weight of cv. Damodar was enhanced at 0.5 % (w/v) NaCl treatment compared to the control seedlings at 25 days. SVI in cv. Jaya decreased with salinity in the laboratory and held conditions. SVI in cv. Damodar, SVI showed little change at 15 days but decreased with salinity of 1-3 % NaCl with an enhancement at 0.5 % NaCl level in the laboratory and at 25 days in field conditions.