ISHS Acta Horticulturae 924: XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): Olive Trends Symposium - From the Olive Tree to Olive Oil: New Trends and Future Challenges
INTERACTION OF CROP LOAD AND WATER STATUS ON GROWTH OF OLIVE FRUIT TISSUES AND MESOCARP CELLS |
| Authors: | E.M. Lodolini, R. Gucci, H.F. Rapoport |
| Keywords: | endocarp, fruit anatomy, irrigation, pulp-to-pit ratio |
| DOI: | 10.17660/ActaHortic.2011.924.10 |
| Abstract:
Field-grown olive trees (Olea europaea L. ‘Leccino’) were hand-thinned at 5-6 weeks after full bloom (AFB) to establish heavy or low crop loads, and then were subjected to three irrigation regimes: a) FI, fully-irrigated with pre-dawn leaf water potential (LPWP) greater than -1.1 MPa; b) DI, deficit irrigated (LPWP between -1 and -3.3 MPa; c) SI, water stressed (LPWP higher than -4.2 MPa). Fruits were sampled at pit hardening and harvest, the mesocarp separated from the endocarp, and their fresh weight and dry weight determined. Additional fruits were fixed in FAE for anatomical studies, their mesocarp and endocarp area measured on transverse slices with an image analysis system connected to a stereo microscope. Mesocarp cell size and number were then determined by microscope after standard paraffin processing. The effect of crop load on the growth of fruit tissues was significantly influenced by the irrigation regime. Within the FI or DI treatments the mesocarp dry weight was higher at low than at high crop load. In the SI treatment, mesocarp dry and fresh weights were 180 and 200% respectively those for trees bearing high crop loads. The pulp-pit ratio was decreased by high cropping for both DI and SI treatments, but was unaffected for the fully-irrigated trees. Overall, there was a notable interaction of crop load and water status on fruit growth processes at multiple morphogenetic levels, including the absolute and relative growth of pulp and pit, mesocarp cell division and enlargement. | |
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