Nutritional factors influencing the distribution of the calcareous and acidic populations in Hypericum perforatum

Abstract

Hypericum perforatum L. was found to have a wide range of distribution occurring on both calcareous and acidic sites. The two populations showed differential responses to macronutrients like calcium and phosphorus and micronutrients like aluminum and manganese. The acidic population showed better growth yield than the calcareous population at lower calcium levels in the medium, but at higher levels the reverse was true. The acidic population had higher uptake of calcium and phosphorus in all the different treatments and of magnesium, potassium, and sodium at low-calcium levels. The individuals of the calcareous population exhibited ‘phosphate toxicity’ at high phosphorus level in the medium while those of the acidic type gave better yield with increase in phosphorus level. Phosphorus uptake was consistently higher in the case of the acidic type compared to the calcareous population. The calcareous population was adversely affected at higher levels of aluminum and manganese and the individuals of this population exhibited severe toxicity symptoms. The acidic population gave good growth yield at both low and high levels of aluminum and manganese. The uptake of aluminum and manganese increased at higher levels of these nutrients in the media. These observations on the two populations have been discussed and it was concluded that besides the direct role of calcium, the differential response to phosphorus, aluminum, and manganese, the availability of which is determined by the pH of the soil, also control the restriction of the two ecotypes to their respective natural habitats.