Paclobutrazol induced growth retardation of mango seedlings.
Murti G. S. R., Upreti K. K.
Author Affiliation: Plant Hormones Laboratory, Division of Plant Physiology & Biochemistry, Indian Institute of Horticultural Research, Hessaraghatta Lake Post, Bangalore 560 089, India.
Indian Journal of Plant Physiology 10 : 9-13
Abstract : Mango seedlings of polyembryonic cv. Bappakai were given soil-drenching treatment with paclobutrazol (PBZ) at 0, 0.34, 0.85 or 1.71 mM. Observations were recorded on morphological characters at weekly intervals, whereas leaf water potential (?w), and levels of chlorophyll, total phenols and endogenous plant growth substances (ABA [abscisic acid], t-zeatin riboside, dihydrozeatin riboside and IAA) were evaluated every month at one month after PBZ treatment. A reduction in seedling vigour was observed at 2 months after PBZ treatment, with the effect being more pronounced at 1.71 mM. The fresh weights of root, leaves and stems were also reduced. The value of ?w was less negative, and the total phenols and chlorophyll contents increased in response to PBZ application. The contents of leaf ABA, t-zeatin riboside and dihydrozeatin riboside were higher in treated seedlings. The results suggested that PBZ-induced growth retardation in mango seedlings is associated with increased levels of ABA and cytokinins, and ?w and phenols in leaves.