Ecophysiology of Salt Excretion in <i>Aeluropus litoralis</i> (Graminae)

Ppllak, Gad; Waisel, Y.

doi:10.1111/j.1399-3054.1979.tb06304.x

Cited by 48 publications

(30 citation statements)

References 17 publications

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“…Moreover, most investigations have dealt with salt impact on plant growth, nutrient relations (e.g. ion content, salt excretion) as well as water content (Pollak and Waisel 1979;Gulzar et al 2003). It is astonishing that no study to date has examined how salinity affects photosynthesis and, in this context, leaf anatomy and organelle ultrastructure.…”

Section: Introductionmentioning

confidence: 99%

Salt impact on photosynthesis and leaf ultrastructure of Aeluropus littoralis

et al. 2007

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The effects of salinity (400 mM NaCl) on growth, biomass partitioning, photosynthesis, and leaf ultrastructure were studied in hydroponically grown plants of Aeluropus littoralis (Willd) Parl. NaCl produced a significant inhibition of the main growth parameters and a reduction in leaf gas exchange (e.g. decreased rates of photosynthesis and stomatal conductance). However, NaCl salinity affected neither the composition of photosynthesis pigments nor leaf water content. The reduction in leaf gas exchange seemed to correlate with a decrease in mesophyll thickness as well as a severe disorganisation of chloroplast structure, with misshapen chloroplasts and dilated thylakoid membranes. Conspicuously, mesophyll chloroplasts were more sensitive to salt treatment than those of bundle sheath cells. The effects of NaCl toxicity on leaf structure and ultrastructure and the associated physiological implications are discussed in relation to the degree of salt resistance of A. littoralis.

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Section: Introductionmentioning

confidence: 99%

Salt impact on photosynthesis and leaf ultrastructure of Aeluropus littoralis

et al. 2007

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“…The capacity of excretion to remove Na and Cl from the Warwick & Halloran (1991) reported variation for plant varies from species to species (Pollack & salinity tolerance among a number of Australian and Waisel, 1979;Waisel, Eshel & Agami, 1986; overseas accessions oi Diplachne fusca (L). Beauv.…”

Section: Introductionmentioning

confidence: 99%

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

Warwick

Halloran

1992

New Phytologist

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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.

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“…Under natural conditions in the field, salt secretion tends to be heavily dependent on soil salinity (Rozema & Riphagen, 1977). Pollak & Waisel (1979) concluded that the optimal conditions for the efficiency of the excretion systems are a combination of low external salt concentration and high atmospheric humidity. It was found that increasing the external concentration of NaCl resulted in an increase in the amount of fluid secreted by salt glands of Limonium delicatulum to a high value at a level of k12 bar.…”

Section: mentioning

confidence: 99%

“…To test the efficiency of the excretion process, the relative excretion (which represents the ratio between absolute excretion and the change in internal Na + content) was computed according to Pollak & Waisel (1979). In this respect, Na + contents of the shoots (after washing), of the same individuals in which the transpiration and excretion rates were measured, were determined at the start and at the end of the experiment.…”

Section: Estimation Of Absolute and Relative Excretionmentioning

confidence: 99%

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Ecophysiology of salt excretion in the xero‐halophyte Reaumuria hirtella

Taha

1998

New Phytologist

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Different aspects of salt excretion from leaves of the xero-halophyte Reaumuria hirtella Jaub. et Sp. (Tamaricaceae) were investigated under the extremely arid conditions of the desert. The diurnal excretion pattern, which gradually decreased toward midday, showed a negative correlation with the daily transpiration pattern. The relative excretion, which is the ratio between the absolute excretion of Na + and the change in its internal content, was maximal at sites with low salinity, and decreased when the concentration of NaCl in the root environment increased. By contrast, the absolute excretion increased from 253 to 323 mmol Na + g −" f. wt per 12 h with increase in the total soil salinity from 0n24 to 1n23 %, respectively. Water stress conditions, caused either by increasing soil salinity or by dryness of the atmosphere, greatly influenced the efficiency of excretion process.Six ions : Na + , K + , Ca# + , Mg# + , Cl − and SO % #− constituted 96n8 % of the d. wt of the field-collected secreted salts. Na + and Cl − , which were the predominating ions in the soil solution of the root environment, were also the predominantly secreted, constituting c. 89 % of salts secreted. The proportion of Na + which was prevented from entry into the roots increased with increasing Na + concentration in the soil solution. More than 67 % of the absorbed NaCl was secreted by leaves during the day. However, the accumulated salts contributed to the osmotic potential (ψ s ) and improved the plant water status. The osmotic potential of the plant sap at the end of the day or during periods of low excretion rates was shown to be decreased k7n3 to k13n7 bar from that in the morning. The fraction of osmotic potential decreased during the day (∆ψ s ) was positively correlated with the soil salinity. These retained salts are expelled from the leaves by increased efficiency of extraction during the night and early morning, so that the plant begins the day with low internal salt content, and the leaf reservoirs become suitable for a new supply. The rejection mechanism at the plant roots and the secretion mechanism at shoots allow the plant to maintain its internal salt content at an approximately constant level despite the great variation in soil salinity.

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Ecophysiology of Salt Excretion in Aeluropus litoralis (Graminae)

Cited by 48 publications

References 17 publications

Salt impact on photosynthesis and leaf ultrastructure of Aeluropus littoralis

Salt impact on photosynthesis and leaf ultrastructure of Aeluropus littoralis

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

Ecophysiology of salt excretion in the xero‐halophyte Reaumuria hirtella

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