Pakistan Journal of Biological Sciences

Year: 2001 | Volume: 4 | Issue: 9 | Page No.: 1070-1074
DOI: 10.3923/pjbs.2001.1070.1074

Anatomy of Lignosus Bean (Dipogon lignosus) IV: Rachis of the Inflorescence

S.M. Abdul Bari and A.K.M. Azad-ud-doula Prodhan

Abstract: Anatomical investigation has been made on the rachis of the inflorescence of lignosus bean {Dipogon lignosus (L.) Verde.) following the standard paraffin method of micro technique. The epidermis of the rachis is single layered with multicellular hair and glandular trichomes. Beneath the epidermis there are 3-6 layers of cortical cells. The pericycle (sclerenchymatous band) forms a discontinuous ring outside the vascular bundles. The vascular bundles are collateral and arranged in a ring. The amount and size of vascular tissues gradually decrease from base to upper part of the rachis. Tanniniferous cells have been observed in the primary phloem region. A complete cambial ring has been found at the basal part of the rachis. The secondary growth is restricted more or less to the lower half of the rachis. In a particular point of the apical region of rachis the secondary growth is almost nil. Some undifferentiated or partially differentiated tracheary and sieve elements fail to mature in upper part of the rachis where the phloem is mostly composed of large parenchymatous cells. There are lots of fibre cells in xylem area. Rays are radially elongated, uniseriate and multiseriate. The pith increases from base upward. The radial length of the rachis gradually decreases towards the apex. It may be concluded that the reduction of phloem tissues in the upper part of the rachis probably allows translocation of insufficient photosynthate, which perhaps contributes shedding of buds, flowers and pods

Keywords: inflorescence, Lignosus bean, rachis, dipogon lignosus and anatomy

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