ISHS Acta Horticulturae 636: XXVI International Horticultural Congress: Key Processes in the Growth and Cropping of Deciduous Fruit and Nut Trees
CELL DIVISION AND EXPANSION IN THE OLIVE FRUIT |
| Authors: | H.F. Rapoport, T. Manrique, R. Gucci |
| Keywords: | Olea europaea L., drupe, mesocarp, endocarp, cell number, cell size |
| Abstract:
We studied the cellular processes involved in mesocarp formation and the expansion patterns for mesocarp and endocarp tissues in fruits of eight olive (Olea europaea L.) cultivars with a wide range of fruit size: ‘Arbequina’, ‘Frantoio’, ‘Gordal Sevillano’, ‘Hojiblanca’, ‘Leccino’, ‘Lechin de Sevilla’, ‘Manzanilla’ and ‘Picual’. Transverse equatorial sections were prepared from ovaries at bloom and fruits sampled throughout the growth season from mature, irrigated olive trees. Tissue areas, cell number and cell size were determined using computer image analysis connected to binocular and ocular microscopes. Mesocarp cell size was similar for all varieties in value and rate of change. Mesocarp cell number was directly related to mesocarp area and final fruit size, with the larger fruits producing greater numbers of cells throughout development. Proportionate to final mesocarp cell number, however, all cultivars showed the same cell division pattern. Mesocarp size differences among varieties depend on both cell number and endocarp size, with smaller fruits having lower cell numbers and smaller endocarps. On the other hand, there are consistent trends in the overall patterns of cell division and expansion, regardless of fruit size. These results for the olive fruit, a drupe originating from a bicarpelate ovary, may be indicative, as well, of the behaviour of other stone fruits, and have important implications for cultural practices such as fruit thinning and deficit irrigation management. | |
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