Response of plant growth to low calcium concentration in the nutrient solution

Many studies have indicated the importance of calcium in fruit disorders. This nutrient is often applied in the nutrient solution in relatively high amounts throughout the crop season, usually without taking into account the physiological stage of the plant. Our study aimed to determine the effect of calcium supply on growth of young, vegetative tomato plants. The experiment was carried out in a growth chamber under fully controlled climate conditions. Treatments consisted of four periods of 1, 3, 7 or 14 days of low calcium (0.5 meq l-1) compared with the control (9 me l-1). Plant dry matter content, total leaf area, leaf dry matter and specific leaf area were not affected after 14 days of low Ca supply. Ca concentrations in young leaves, stem, and roots were quickly reduced after only 1 day of low-Ca. After 14 days, Ca concentration in all plant organs (leaves, stems and roots) was reduced by approximately 70% compared to control plants. Stomatal regulation was not affected by this level of calcium stress as leaf transpiration in treated plants was similar to control plants with the same leaf area. Our data show that calcium supply and consequently Ca concentration in the plant can be reduced drastically without any adverse effect on growth.