EFFECTS OF TEMPORARY CALCIUM DEFICIENCY ON THE INCIDENCE OF A NUTRITIONAL DISORDER IN MELON

The annual production of melon fruit in France amounts to ca. 320,000 tons.
A physiological disorder called "vitrescence" has appeared recently: the pulp colour is more intense, with a vitreous aspect and a deliquescent texture.
The symptoms are likely to be related to the calcium nutrition of the fruit.
Melon plants (Cucumis melo L. var.
Maestro) were grown hydroponically under a plastic tunnel in Southern France.
After the application of a temporary calcium deficiency for 17 days to plants bearing fruits whose age was in the range 3–20 after anthesis, the supply of calcium was resumed and the fruits were harvested at maturity (37 days). When the calcium deficiency was applied to plants bearing young fruits, 50 to 100% of the fruits displayed vitrescence symptoms: their calcium contents were lower than those of the control fruits ; a relationship between the vitrescence incidence (%) and the calcium content of the pulp was observed.
At such a developmental stage, calcium deficiency resulted in irreversible damage which could not be counter-balanced by calcium supply resumption.
In contrast, when the calcium deficiency was applied at a more advanced developmental stage (20 days after anthesis), the stress had no effect on the calcium already accumulated by the fruit and thus had only a limited incidence on the appearance of vitrescence.
In the control plants grown throughout the experiments on nutrient solutions containing calcium, the fruits did not display any vitrescence symptoms.

International Symposium on Growing Media and Hydroponics

I. Jean-Baptiste, P. Morard, A. Bernadac

Cucumis melo L., vitrescence, fruit, calcium content

https://doi.org/10.17660/ActaHortic.1999.481.49