Salt tolerance: a physiological study
1989
Cabuslay, G.S. | Akita, S. (International Rice Research Inst., Los Banos, Laguna (Philippines). Plant Physiology Dept.)
Fourteen rice cultivars-- Pokkali, its three semi-dwarf variants obtained by tissue culture, two IR cultivars, and four japonica cultivars/variants-- were studied. One-week-old seedlings were salinized with NaCl at eight and 15 PS/m for six and 12 days. Percent survival was negatively correlated with leaf Na content after salinization with 15 ds/m for 12 days, with Pokkali and variants having the highest survival and the lowest Na content in the leaf. The leaf blade, Na/sheath, and Na ratio of these materials were much lower than those of other cultivars after salinization with 15 ds/m for 6 days, suggesting a regulatory mechanism which prevent the entry of Na ions into the leaf. Growth analysis of rice seedlings in salinized condition showed that salinity caused greater reduction in leaf area than in total dry weight. Salinization with 8 ds/m from 6 to 12 days reduced the relative growth rate (RGR) of Pokkali and its variants to 4%, on the average; those of susceptible cultivars were reduced to 35%. Using a 15 ds/m salinized solution, on the other hand, reduced the RGR of Pokkali and variants to 34% while those of susceptible cultivars were reduced to 80%.
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