Abstract
Paclobutrazol [(2RS,3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)pentan3-ol], formulated as GFU 265, applied at 100, 250, and 500 mg plant−1 to the soil of container-grown sweet orange [Citrus sinensis (L.) Osbeck cv. Valencia], suppressed plant weight, stem height, leaf size, and total leaf area. At the 500-mg dosage, total plant dry weight was reduced by 61%, stem height by 74%, and both leaf biomass and area by 80%, as compared to control plants. All paclobutrazol dosages induced fibrous root thickening and increased their soluble sugar and starch content. Fresh root biomass was 14 to 40% higher and root:shoot ratios were increased three- to sixfold for treated plants. Paclobutrazol applications of 250 and 500 mg plant−1 reduced leaf photosynthetic rate, ribulose bisphosphate carboxylase activity, total nonstructural carbohydrates, and dark respiration 70 to 80% of the control plants. Reductions of leaf photosynthetic rate, carboxylase activity, and photosynthate by paclobutrazol contributed to biomass reduction in treated sweet orange.
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Vu, J.C.V., Yelenosky, G. Growth and photosynthesis of sweet orange plants treated with paclobutrazol. J Plant Growth Regul 11, 85–89 (1992). https://doi.org/10.1007/BF00198019
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DOI: https://doi.org/10.1007/BF00198019