DEVELOPMENTAL ANATOMY OF GINGER RHIZOMES - II. ONTOGENY OF BUDS, ROOTS AND PHLOEM

Abstract

Developmental pattern, growth and branching behaviour of rhizomes' of ginger were studied. Axillary buds are present at each node. Secondary and tertiary branches originated from the axillary bud from the adaxial sides of the leaf or scale leaf. Cytohistological zonation of rhizome buds and adventitious roots was studied. The phloem mother cell in ginger originated from the primary thickening meristems. The sieve tubes develop by pycnotic degeneration of nuclear structure. The fragmented multinuclear stages were observed in several sieve tube members. The sieve element has an average length of 76.8 I'm and width of 8.76 I'm. The sieve plates are transverse to oblique with varying degrees (110-140°) of inclination. Slime body exists only in early stages of development. No definitive callose was observed in mature sieve tube. The number of companion cells per sieve tube member varied from four to eight; these showed dense cytoplasm and prominent nuclei. Phloem parenchyma and fibres were also present.