ISHS Acta Horticulturae 747: VIII International Symposium on Protected Cultivation in Mild Winter Climates: Advances in Soil and Soilless Cultivation under Protected Environment
INFLUENCE OF ADDITIONAL NIGHT IRRIGATIONS ON PETAL CALCIUM LEVELS AND POSTHARVEST LIFE OF SOILLESS ROSES |
| Authors: | M.C. Cid, L. Morales, A.R. Socorro |
| Keywords: | protected cultivation, cut-flowers, vase-life, sodium, irrigation regime |
| Abstract:
Calcium plays an important role in post-harvest quality and disease susceptibility of rose flowers. Under the usual growing conditions of mild winter climates (characterised by high radiation and vapour-pressure deficit), and barring salinity problems or antagonistic nutrient overdoses which can impair uptake, soilless-cultured roses exhibit normal-to-high Ca content in leaves but little in flower buds. As calcium is considered to move mainly in the xylem, with the transpiration stream, and its translocation through the phloem is extremely limited, its concentration in low transpiring organs, such as flower buds, should be strongly dependent on xylem flow due to root pressure. To test the possibilities of enhancing bud Ca levels, an experiment was set up to compare vase-life and petal Ca-content of soilless-cultured roses cv. ‘Jaguar’ under two irrigation regimes: the standard ten applications during daylight hours only, and the same amount of solution divided to provide ten daytime applications and three at night; different tuff sizes were also tested. Irrigation at night increased the Ca content in petals at least 10% and caused a similar reduction of Na, irrespectively of tuff particle-size; analogous effects were produced on Ca and Na concentrations in the diagnostic leaves. Vase life was extended at least one day more two days for 54% of flowers and bud opening was enhanced; no differences between treatments were found for number of stems, or stem length and weight. Night irrigation pulses may be a commercially acceptable practice to increase rose quality. | |
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