The Role of Vitamins and Micronutrient Elements in the Nutrition of the Apical Meristem of Pea Roots.

Abstract

A synthetic nutrient medium capable of supporting growth of excised half mm. root tips of the garden pea, Pisum sativum variety Alaska, is reported. Half mm. root tips include 300[mu] root cap plus 200[mu] immature tissues which lack any mature vascular tissue. The vitamins, thiamin and nicotinic acid, are required at relatively high levels. By use of a medium purified of heavy metals, the essentiality for root elongation of the micronutrients Zn, Mn and Mo has been demonstrated. It is concluded that half mm. root tips are practically devoid of these required vitamins and micronutrient elements. Such extremely small root tips are especially valuable in the analysis of nutritional requirements, since such nutritional requisites are rapidly depleted in isolated root culture. The possible role of mature vascular tissues in the nutrition of the meristem is discussed.