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Ethylene limits abscisic acid‐ or soil drying‐induced stomatal closure in aged wheat leaves
Author(s) -
CHEN LIN,
DODD IAN C.,
DAVIES WILLIAM J.,
WILKINSON SALLY
Publication year - 2013
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12094
Subject(s) - abscisic acid , ethylene , endogeny , chemistry , water content , horticulture , 1 aminocyclopropane 1 carboxylic acid , plant physiology , botany , biology , catalysis , biochemistry , geotechnical engineering , engineering , gene
The mechanism of age‐induced decreased stomatal sensitivity to abscisic acid ( ABA ) and soil drying has been explored here. Older, fully expanded leaves partly lost their ability to close stomata in response to foliar ABA sprays, and soil drying which stimulated endogenous ABA production, while young fully expanded leaves closed their stomata more fully. However, ABA ‐ or soil drying‐induced stomatal closure of older leaves was partly restored by pretreating plants with 1‐methylcyclopropene (1‐ MCP ), which can antagonize ethylene receptors, or by inoculating soil around the roots with the rhizobacterium V ariovorax paradoxus 5C ‐2, which contains 1‐aminocyclopropane‐1‐carboxylic acid ( ACC )‐deaminase. ACC (the immediate biosynthetic precursor of ethylene) sprays revealed higher sensitivity of stomata to ethylene in older leaves than younger leaves, despite no differences in endogenous ACC concentrations or ethylene emission. Taken together, these results indicate that the relative insensitivity of stomatal closure to ABA and soil drying in older leaves is likely due to altered stomatal sensitivity to ethylene, rather than ethylene production. To our knowledge, this is the first study to mechanistically explain diminished stomatal responses to soil moisture deficit in older leaves, and the associated reduction in leaf water‐use efficiency.