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ABA‐deficient ( aba1 ) and ABA‐insensitive ( abi1‐1, abi2‐1 ) mutants of Arabidopsis have a wild‐type stomatal response to humidity
Author(s) -
Assmann Sarah M.,
Snyder Jo Ann,
Lee YuhRu Julie
Publication year - 2000
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 - 10.1046/j.1365-3040.2000.00551.x
Subject(s) - guard cell , abscisic acid , transpiration , stomatal conductance , arabidopsis , humidity , chemistry , mutant , arabidopsis thaliana , vapour pressure deficit , wild type , biophysics , botany , horticulture , biochemistry , biology , photosynthesis , meteorology , gene , physics
ABSTRACT In most plant species, a decrease in atmospheric humidity at the leaf surface triggers a decrease in stomatal conductance. While guard cells appear to respond to humidity‐induced changes in transpiration rate, as opposed to relative humidity or vapour pressure difference, the underlying cellular mechanisms for this response remain unknown. In the present set of experiments, abscisic acid (ABA)‐deficient ( aba1 ) and ABA‐insensitive ( abi1‐1 and abi2‐1 ) mutants of Arabidopsis thaliana were used to test the hypothesis that the humidity signal is transduced by changes in the flux or concentration of ABA delivered to the stomatal complex in the transpiration stream. In gas exchange experiments, stomatal conductance was as sensitive to changes in vapour pressure difference in aba1 , abi1‐1 and abi2‐1 mutant plants as in wild‐type plants. These experiments appear to rule out an obligate role for either the concentration or flux of ABA or ABA conjugates as mediators of the guard cell response to atmospheric water potential. The results stand in contrast to the well‐established role of ABA in mediating guard cell responses to decreases in soil water potential.