Mineral Nutrition and Calcifuge Behaviour in Hypericum

Abstract

The calcifuge species considered in this work were Hypericum pulchrum L. and H. humifusum L. Grime (1959) and Hutchinson (1967) have pointed out that both these species show susceptibility to lime-induced chlorosis. Grime also showed that addition of chelated iron relieved the lime-induced chlorosis in H. pulchrum and produced an increase in growth. The lime-tolerant species here used for comparison was H. perforatum L., which occurs on natural and semi-natural soils of a wide range of acidity. Ramakrishnan (1969) has shown that there is some differentiation of edaphic ecotypes in H. perforatum; in the work described in this paper, seed derived from a single population occurring on a calcareous soil was used. The three species used were considered suitable for the experiments described because they show reasonably close morphological similarity, and because they have small seeds which are easily germinated. The seeds of H. perforatum and H. pulchrum each weigh about 0 1 mg, those of H. humifusum about