ISHS Acta Horticulturae 275: International Symposium on the Culture of Subtropical and Tropical Fruits and Crops
RESPONSES TO PACLOBUTRAZOL OF POTTED 'HASS' AVOCADO TREES |
| Authors: | P.R.R. Symons, P.J. Hofman, B.N. Wolstenholme |
| Abstract:
Paclobutrazol (as Cultar®) at rates of 0.31, 0.625, and 1.25 g m-2 canopy area, was applied as a drench to potted ‘Hass’ on ‘Duke 7’ avocado trees grown in a glass house. Shoot length and diameter, internode length, leaf area, leaf and branch number/plant and stem, leaf and root dry masses were reduced by paclobutrazol treatment. Assimilate partitioning favoured the roots, as reflected by significantly higher root:shoot ratios obtained from treated plants. Leaf N and K concentrations were reduced by paclobutrazol treatment. Leaf Mg concentrations were increased with treatment, particularly at the highest concentration, while B concentration was significantly lower at the highest paclobutrazol rate. Leaf Ca and P showed no significant response. Chlorophyll a content was highest at the highest rate of application, but chlorophyll B was unaffected. Chloroplasts from the highest application rate contained more starch granules than those in the control leaves. Responses to paclobutrazol are explained in terms of carbohydrate trends as analysed in leaves, stems and roots taken at harvest, 111 days after treatment. | |
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