Twelve years ago Priestley and Ewing (1923) reported that in certain plants, normally showing but little development of stem-endodermis, an extensive formation of this layer could be induced by etiolation. (Note: In this paper the term endodermis is used only when the layer shows characteristic structural features—in the present case the Casparian strip.) A later paper by Priestley (1926) dealt with the same subject. The specified plants with which this result was obtained consisted of four closely related species, namely, Vicia Faba, V. sativa*, Pisum sativum, and Lens esculenta*, and also Solanum tuberosum. (The statements relating to the species marked with an asterisk are based on unpublished work carried out at Leeds, kindly placed at the author's disposal by Professor J. H. Priestley.) In these plants a primary endodermis, though present only at the base of the normal shoot, was described as extending to a considerable height in the etiolated shoot. It was concluded that the absence of endodermis from the greater part of the shoot of these plants, when grown under normal conditions, arises from the inoperation, in the presence of light, of the mechanism forming the Casparian strip.
Biological control of Phaseolus vulgaris and Pisum sativum root rot disease using Trichoderma species