Accumulation and excretion of sodium, potassium and chloride from leaves of two accessions of Diplachne fusca (L.) Beauv.

Abstract

SUMMARYWhen two accessions of brown beetle grass [Diplachne fusca (L.) Beauv. syn. Leptochloa fusca (L.) Kunth], differing in tolerance to salinity, were exposed to NaCl over 15 d, Na concentrations were constant in the shoot. However, there were differences in shoot Na concentration between the two accessions which were manifest after 5 d exposure to 100 mol m~^ NaCl. Na and Cl concentrations in the shoot were found to be controlled within a narrow range and did not increase any further after 5 d exposure to NaCl. Leaves of differing maturity and growth rate of both accessions did not differ in their Na concentrations. Na concentrations remained stable in leaves of differing ages after the first 6 d of exposure to NaCl whereas K declined with time, possibly due to remobilization to younger leaves. Avoidance of high concentrations of Na in younger leaves by its sequestration in older tissue does not appear to he a salt-tolerance mechanism in D. fusca. The primary mechanism of exclusion of Na and Cl from the plant is in the root, with secondary control of leaf Na and Cl concentration by excretion of excess Na and Cl through leaf salt-glands. Total Na uptake for the relatively salt-tolerant accession of D. fusca. Ml, was similar to that for the relatively intolerant accession F3, although Ml had a lower Na concentration in its leaves than F3 after 5 d exposure to NaCl. This suggests a possible mechanism for the higher tolerance of Ml to NaCl. Leaf Na concentration was significantly higher in F3 than Ml, but Ml had significantly higher Na excretion rates than F3. The leaf salt-glands of both accessions of D. fusca were found to be capable of excreting approximately 50-80 % of the Na entering the leaf.

Salinity Effects on Germination and Plant Growth of Prairie Cordgrass and Switchgrass

“…The same result was also found on K + uptake in shoots and stems of Baccaurea parviflora [35] and Atriplex hortensis [53]. Halophytes maintain or increase K + selectivity under high salt stress through three possible mechanisms for salt tolerant: salt exclusion from leaves and stems, prevention of Na + loading into the xylem, and prevention of Na + absorbing from roots [10,19,51]. Our results of low Na + content in root and shoot biomass and the existence of salt glands on Red River leaves and stems suggest that Red River has at least one or more these salt-tolerance mechanisms.…”

Effect of salinity on growth, ion accumulation and the roles of ions in osmotic adjustment of two populations of Suaeda salsa

“…The ability to regulate Na + or Cl − uptake and transport to the shoot is crucial for salt resistance in plants (Greenway and Munns 1980;Tester and Davenport 2003;Warwick and Halloran 1992). Under natural condition Na + and Cl − concentrations are higher in sheaths than in leaf blades of, for example, Diplachne fusca (L.) Beauv., indicating that the species has the capacity to sequester high levels of Na + and Cl − in the sheath away from the leaf blade as well as maintaining a high selectivity for K + over Na + (Warwick and Halloran 1991).…”

Waterlogging and salinity effects on two Suaeda salsa populations

“…The ability to regulate Na + or Cl − uptake and transport to the shoot is also crucial for salt tolerance in plants (Greenway and Munns 1980, Munns 2005, Tester and Davenport 2003, Warwick and Halloran 1992;). It has been shown that Cl − ‘exclusion’ is a key trait for salt tolerance in Lotus tenuis (Teakle et al 2007).…”