Plant growth regulator taken up into the xylem through the leaves, stems, or roots. PaclobutrazolPlant growth regulatorFRAC 3; DMI: triazole NOMENCLATURE ... (pH 7, 10 days). APPLICATIONS Mode of action Plant growth regulator taken up into the xylem through the leaves, stems ... chrysanthemums, begonias, freesias, poinsettias and bulbs) to inhibit growth; on rice to increase tillering, reduce lodging, and ...