Compositions and methods for modifying the sensitivity to abscisic acid, of seeds and vegetative tissues of plants. The compositions comprise novel nucleotide molecules configured for expressing an abscisic acid-binding protein, i.e., ABAP1, comprising an amino acid sequence set forth in SEQ ID NO: 10. The methods comprise the steps of constructing a nucleotide molecule by fusing a nucleotide coding sequence set forth in SEQ ID NO: 9 with a regulatory nucleotide sequence selected for over-expression or for under-expression of the coding sequence, stably introducing the nucleotide molecule into the genome of a recipient cell from a seed-producing plant, culturing the recipient cell into a whole recipient plant and then further culturing the recipient plant to produce mature recipient seeds, and harvesting the recipient seeds. The recipient seeds and whole plants produced therefrom have modified sensitivities to ABA thereby enabling regulation of germination, physiological function and plant productivity.