ISHS Acta Horticulturae 51: Symposium on Protected Cultivation of Flowers and Vegetables
INFLUENCE OF THE WATER STATUS ON THE GROWTH AND FRUIT SETTING OF PEPPER AND EGGPLANT IN PROTECTED CULTIVATION. |
| Authors: | E. POCHARD, P. CORNILLON |
| Abstract:
A comparison between "normal" plants grown in the field during the summer and plants grown under glass in a period of short days shows that the last differ by many characters. The most striking are hyperdevelopment of the leaves and flower shedding. These features appear to be linked to an almost permanent water saturation of the leaves and a low dry matter content. In one experiment we studied six eggplant cultivars planted in october in a heated glasshouse. Two groups were apparent. In the first group, the proportion of functional flowers in december varied from 0 to 2 per cent ; in the second, from 23 to 53 per cent. On the 15th of january, the dry matter content of the standard leaves was about 300 mg.dm-2 in the first group and 400 in the second (probability less than 0.01 %). The water deficit was 3.5 and 7.1 respectively (probability less than 0.01). After furrow irrigation, a simultaneous drop in the values of the three parameters was observed, suggesting a direct influence of the water status on the other characters. In two experiments (plants grown on liquid medium or in pots with peat substratum) the osmotic potential of the mineral solution was changed before the flowering period by changing the concentration of the mineral salts. Starting with Hoagland solution (0.5 bar), two solutions have been compared (0.25 and 1.5 bar) on two eggplant and pepper cultivars. Quantities of water and dry matter per unit area of leaf are always increased by using the most concentrated solution but the different genotypes do not respond to the same extent. The effect on fruit setting was not apparent because all the flowers dropped in the trial on eggplant (period studied : december and january, dry matter content 170 to 250 mg.dm-2) and all the flowers were functional in the trial on pepper (april and may, dry matter content 380 to 600 mg.dm-2). Optimum concentration depends on the water consumption of the plants which, in turn, is determined by the growing season and the variety used. | |
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