Development of intraxylary phloem and internal cambium in Ipomoea hederifolia (Convolvulaceae)

摘要: Abstract In Ipomoea hederifolia L. (Convolvulaceae), internal/intraxylary phloem originated as isolated strands from the procambially derived cells after formation of protoxylem and protophloem. Bands internal were apparent in sixth internode development metacambium. relatively thick stems several small arcs/segments cambium ensues parenchyma between Though all segments active, some them (two located opposite to each other) more active. Bidirectional differentiation these gave rise secondary xylem centrifugally centripetally, resulting inverted vascular bundles. Rest unidirectional formed only centripetally. Like external cambium, was non-storied. Structurally, composed axial radial system which rays we...