(Color plate page CP4). Phenotypes of ABA-deficient mutants. A) Inability to regulate transpiration results in a wilty phenotype and reduced growth of the aba2 mutant in Nicotiana plumbaginifolia. B) Precocious germination of seeds in the maize mutant, vp14. Courtesy of Drs.B.C. Tan and D. R. McCarty. C) A high sugar concentration (10% glucose) inhibits growth of wild-type seedlings of Arabidopsis, whereas aba1 seedlings are sugar insensitive.