Articles
EFFECT OF SALINITY AND WATERING LEVEL ON THE CALCIUM CONTENT OF TOMATO FRUIT *)
A second batch of plants were grown in peat with different amounts of water (60, 80, 100 and 120% of the requirement estimated from solar radiation integrals) but equal quantities of nutrients.
Increasing the salinity of the NFT solution progressively depressed the fresh weight of the fruit.
Salinities above 4 mS increased the dry matter content and decreased not only the calcium content of the dry matter (%) but also the total and bound calcium contents (mg) of the fruit.
Decreasing the amount of water applied also reduced the fresh weight of the fruit.
When less than 100% of the estimated water requirement was applied, the dry matter content of the fruit increased whilst the calcium content of the dry matter (%) and the total and bound calcium contents (mg) of the fruit declined.
The soluble calcium content was not affected by high salinity or restricted watering, and accounted for 23–29% of the calcium in the whole ripe fruit.
The salinity treatments in NFT depressed the fruit weight and calcium contents more markedly than did the watering treatments in peat, but resulted in a slightly smaller increase in dry matter content and a lower incidence of blossom-end rot in the most adverse treatment (0.2% in NFT compared with 1.2% in peat). Healthy fruit grown in either substrate contained more than 0.07% Ca whereas those with blossom-end rot contained less than 0.05% Ca.