THE UPTAKE OF ZINC AND CALCIUM FROM SOLUTION CULTURE BY ZINC‐TOLERANT AND NON‐TOLERANT SILENE MARITIMA WITH. IN RELATION TO CALCIUM SUPPLY

Abstract

SUMMARYInter‐population variation in the uptake of calcium from solution culture was studied in a range of zinc‐tolerant and non‐tolerant populations of Silene maritima under conditions of high zinc and calcium. The populations exhibited great variability in their patterns of calcium uptake similar to that previously reported for zinc. The effects of variation in calcium supply on yield and calcium and zinc uptake by one zinc‐tolerant and one non‐tolerant population are described. Little difference in yield‐response to calcium was detected between the two populations but they showed major differences in the uptake and accumulation of zinc and calcium and their transport from root to shoot. Total zinc uptake was little affected by increases in calcium level in the tolerant plants but was decreased significantly in the non‐tolerant plants. At the higher calcium levels, total zinc uptake by tolerant plants was also significantly greater than by the non‐tolerant but the populations did not differ in total calcium uptake. Evidence for a reduction in zinc transport in both populations resulting from increased calcium uptake is presented. Marked stimulation of zinc accumulation by the roots of the tolerant population resulting from increases in the external calcium level is interpreted as a possible corollary of zinc tolerance in this tolerant population. The role of calcium in the internal detoxification of zinc is discussed.