EFFECT OF CALCIUM STRESS ON THE CALCIUM STATUS OF TOMATOES GROWN IN NFT

P. Adams, A.M. El-Gizawy
Tomatoes were grown in recirculating solutions containing 175 mg 1-1 Ca and adequate levels of other essential nutrients. Calcium stress was applied by draining the system, flushing the root mat with deionised water and then growing the plants in deionised water to which all nutrients except calcium were added.

Using trusses 2–8 on indeterminate plants, a calcium stress of 7 days before sampling had no effect on fruit size but reduced the concentration of calcium in the dry matter in young fruits of <22 days after anthesis (24–46%) more than in older fruits of >35 days (8–10%). Similar decreases were found in total calcium (mg) in the fruits. When the 7-day stress was followed by 7 days with 175 mg 1-1 Ca in the nutrient solution, the concentration of calcium in the young fruits (14–35 days) was reduced on average by 27%, with similar results for total calcium.

A calcium stress of 21 days reduced the concentration of calcium in young fruits from trusses 13–15 to 0.03% as compared with >0.10% Ca in those continuously supplied with calcium. The total calcium content of the fruits was 0.3 mg/fruit after 7 days of stress and 0.9 mg after 21 days compared with 0.5 and 3.0 mg, respectively, in normal fruits.

Foliar symptoms of calcium deficiency appeared on the young leaves of plants bearing 15 trusses after 21 days of calcium stress, and were severe after a further 8 days. After 21 days of stress, 20% of the young fruits on trusses 13–15 had developed blossom-end rot; most of the young fruits were affected after 35 days of stress. The concentration of calcium in the leaves declined from 0.48% after 7 days of stress to 0.04% after 35 days, when the top of many plants died.

Adams, P. and El-Gizawy, A.M. (1988). EFFECT OF CALCIUM STRESS ON THE CALCIUM STATUS OF TOMATOES GROWN IN NFT. Acta Hortic. 222, 15-22
DOI: 10.17660/ActaHortic.1988.222.1
https://doi.org/10.17660/ActaHortic.1988.222.1

Acta Horticulturae