Phloem loading in squash.
Squash (Cucurbita pepo L. var. melopepo torticalis, Bailey) leaves were supplied with (14)C-sucrose, then specific radioactivities of the glucose and galactose moieties of translocated stachyose were determined. In every case, the specific radioactivity of the galactose moiety was greater than that of the glucose moiety. It is concluded that the stachyose was not synthesized at either the phloem-loading site or subsequent to phloem loading, but rather in cells that were not a part of the translocation system, possibly the mesophyll cells.
Hendrix
J E
JE
Department of Botany and Plant Pathology, Colorado State University, Fort Collins, Colorado 80523.