biologia plantarum

Biologia plantarum 44:95-99, 2001 | DOI: 10.1023/A:1017978506585

Salt Tolerance in Aquatic Macrophytes: Ionic Relation and Interaction

N.P. Rout¹, B.P. Shaw¹

¹ Institute of Life Sciences, Orissa, India

Effects of seawater salinity (SWS) and pure NaCl on the intracellular contents of Na⁺, K⁺, Mg²⁺, Ca²⁺, chlorophylls (Chl) and carotenoids (Car) were studied in three submerged aquatic macrophytes, Hydrilla verticillata, Najas indica and Najas gramenia, which differed in their tolerance to salinity. NaCl resulted in significant increase in Chl/Car ratio in the salt-sensitive H. verticillata and moderately salt-tolerant N. indica, but not in the salt-tolerant N. gramenia. SWS treatment did not result in any significant change in the ratio. The intracellular content of Na⁺ increased significantly in all the test plants upon exposure to both NaCl and SWS. The content of K⁺ decreased significantly in these plants upon salinity treatment, except in N. gramenia. The contents of Ca²⁺ and Mg²⁺ decreased significantly upon NaCl treatment and remained unchanged or increased upon SWS treatment. No relationship between salt tolerance and K⁺/Na⁺ ratio was observed. The maintenance of a minimal level of K⁺ was observed to be the most probable requirement of salt tolerance in aquatic macrophytes.

Keywords: calcium protection; carotenoids; chlorophylls; Hydrilla verticillata; Najas gramenia; Najas indica; oxidative stress; seawater salinity; sodium chloride

Subjects: calcium protection, ionic relation and interaction; calcium, seawater and NaCl salinities; carotenoids, salt stress; chlorophylls, salt stress; Hydrilla verticillata; magnesium, salt stress; Najas gramenia; Najas indica; oxidative stress, ionic relation and interaction; potassium, salt stress; salt stress, chloroplast pigments; salt tolerance, Na, K, Mg, Ca relation and interaction; seawater salinity, ionic relation and interaction

Published: March 1, 2001  Show citation