The changes induced in the anatomical structure of Vicia faba by the absence of boron from the nutrient solution

The chemical. elements essential for the healthy growth of plants are now recognized to be more numerous than was originally supposed, and although some must be supplied in considerable quantity, of others only a trace is required. Boron is an example of the latter type of element. Experiments at Rothamsted have shown that Vicia Faba (broad bean) and several other leguminous plants fail to complete their development in water or sand culture unless a trace of this element is supplied, 1 part H3BO3 in 25,000—12,500,000 parts of nutrient solution being sufficient (1, 4). In its absence characteristic symptoms are exhibited in both shoot and root. In the case of the broad bean the flower buds shrivel and fall off and the stem withers and blackens at the apex, the injury gradually travelling down the plant; the root system is stunted, the laterals being few in number and often thickened. A comparison between the anatomical structure of such abnormal shoots and roots with those of the healthy plant is the subject of the present paper.