Pattern of salt accumulation and its impact on salinity tolerance in two halophyte grasses in extreme saline desert in India

摘要

Halophytes growing in natural saline desert environment survive high levels Of salinity adopting suitable mechanisms. Scientific information on such survival mechanisms can be useful in devising management options for extreme saline soils. A field survey on two major halophytes [Aeluropus lagopoides (Linn.) Trin. Ex Thw. and Sporobolus marginatus Hochst. ex A. Rich.] was carried out in the saline desert of Northwest India, Great Rann of Kachchh, to study the pattern of ion accumulation under natural conditions and to assess survival mechanisms of these halophytes. Studied areas in Great Rann had electrical conductivity (EC) values ranging 0.15-83.1 dSm(-1). Occurrence of Sporobolus was observed at sites having salinity as high as 83.06 dSin(-1) and Aeluropus up to 22.7 dSm(-1). Greater accumulation of Na+ and Cl- ions were observed in the roots of these halophytes indicating its restricted uptake by them. There was selective absorption of K+, Ca2+ and SO42+ in the leaves of Aeluropus and K+, Ca2(+), Mg2+ and SO42- in Sporobolus. With increase in soil salinity, the uptake of Na+, K+ and SO42- were reduced in Aeluropus whereas the uptake of Na+, K+ and Cl- was increased in Sporobolus. Possible mechanisms of salt tolerance of these halophytes are also discussed.