AND COTTON (GOSSYPIUM HIRSUTUM L.)

A B S T R A C T Callose accumulated in the tissues of boron deficient bean and cotton plants, the extent and distribution of which depended on the species. Sieve plates in the phloem of boron deficient bean were characterized by heavy plugs of callose, while the sieve plates of boron deficient cotton were essentially unaffected. Translocation of "4C was, however, drastically reduced in both plants. It is suggested that callose deposition in boron deficient plants is a secondary effect of cellular damage. Toxic amounts of boron have been found to induce excessive deposition of callose in parenchyma tissue of the primary leaves of Phaseolus vulgaris (McNairn and Currier, 1965) and in sieve tubes of petioles of Cucurbita maxima (Eschrich et al., 1965).