Calcium status and chilling injury in maize seedlings

The dependence of growth and chilling injury as well as of calcium fractions in plant tissues on calcium rate were studied in seven-day-old maize (Zea mays L.) seedlings. The plants were grown in water culture on Knop solution with a calcium concentration varying from 0 to 30 mM, in the light or in the dark, and at optimal (25 degrees C) and low (2 degrees C for 24 h) temperatures. The calcium concentration of 6 mM was found to be the best for seedling growth. Calcium content in plants increased in parallel to the rise in Ca2+ concentration in the solution. The degree of chilling injury, as judged from the electrolyte leakage, was lowest at a calcium concentration of 6 mM and rose with both the increase and decrease in Ca2+ rate. With calcium accumulation in the seedlings, the fraction of free calcium increased. The most pronounced rise in this fraction was observed in chilled plants at 30 mM calcium in the solution. This work considers the possibility for exogenous calcium to influence chilling injury via the increase in free Ca2+ content.