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Mechanisms of chloride partitioning in the leaves of salt‐stressed Sorghum bicolor L.
Author(s) -
Boursier P.,
Läuchli A.
Publication year - 1989
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1989.tb05389.x
Subject(s) - vascular bundle , vacuole , chloride , sorghum , epidermis (zoology) , biophysics , parenchyma , chemistry , sorghum bicolor , botany , biology , biochemistry , cytoplasm , anatomy , agronomy , organic chemistry
Chloride transport in sheath and blade tissue and the cellular distribution of Cl ‐ were investigated in an attempt to determine the physiological basis of the preferential accumulation of Cl ‐ in sheaths of salt‐stressed sorghum ( Sorghum bicolor L.). Import and export of 36 Cl ‐ in leaf sheaths and blades of intact sorghum were followed over a 2 week period. X‐ray microanalysis of frozen‐hydrated bulk tissue samples was used to determine the accumulation of Cl ‐ and other elements in the vacuoles of sheath and blade cells. Sheath tissue accumulated Cl ‐ despite a relatively high Cl ‐ turnover rate. Chloride was shown to accumulate in most cell types of the sheath, particularly in adaxial epidermal cells. After an initial increase in the concentration of Cl ‐ , blade tissue regulated Cl ‐ levels within certain limits. Chloride levels in blades were greater in the abaxial and adaxial epidermal cells than in other cell types. The epidermal cells of blades accumulated Cl ‐ to approximately the same concentration as sheath epidermal cells. The Cl ‐ concentration in the photosynthetically active mesophyll and bundle sheath cells, however, remained low. Thus, the partitioning of Cl ‐ previously observed in the leaves of salinized sorghum apparently results from the ability of bundle sheath and mesophyll cells to maintain concentrations of Cl ‐ at lower levels than do epidermal cells. In addition, the relatively large sheath parenchyma cells tend to serve as reservoirs for the storage of Cl ‐ .