THE MORPHORLOGY, STRUCTURE AND DEVELOPMENT OF WINTER BUD IN BRASENIA SCHREBERI GMEL.

The paper describes the results of a study of winter bud in Brasenia schreberi Gmel. The winter bud consists of a thickened stem, dwarf leaves with thickened petioles, and the whole organ is enveloped in the gelatinous layer.The blade of the leaf has a more compact mesophyll, lacking extensive intercellular spaces, it entirely lacks the stomata, and it has only one poorly developed palisade cell layer. The compact tissues and the abundant plastids are adapted to store starch.The vascular tissues of petiole show the characteristic double phloem and single canal representing xylem. The central portion of the stem is occupied by a pair of double phloem vascular bundles. The winter bud as an absiss-layer is detached from the parent plant, and falls to the bottom of the pond where it spend the winter, These winter buds serve as a vegetative organ. The winter buds would be killed by temperature below about 4℃,