Authors:Bhat K.V
Abstract:The anatomical changes occurring during the maturation of culms were investigated in two common species of Indian bamboos, namely Bambusa bambos (L.) Voss and Dendrocalamus strictus Nees by a comparative study of culm internodal material of different ages between 2 and 60 months. The culm wall consisted of ground parenchyma tissue enclosing a large number of fibro-vascular bundles, which varied in size, structure and abundance in different parts of the culm, both in the axial and radial direction. The main change that occurred during culm maturation was the thickening of cell walls and lignification. Cell-wall thickening and lignification progressed from the outer to the inner parts of the culm wall, and from the culm base towards the top. Within a fibro-vascular bundle, these changes first occurred in fibres contiguous to the vascular tissues and then progressed to outer parts of the bundle. In the peripheral fibrous strands of the bundles, the outermost fibres matured first followed by the inner ones. Cell-wall thickening of fibres was accomplished by addition of lamellae leading to a polylamellate cell-wall structure. In ground parenchyma, although the wall thickening was evident, lamellation was not distinct. These changes in cell-wall structure led to increase in basic density of the culm material. The increase in density was dramatic during the first two years in both B. bambos and D. strictus. It became more gradual during the third year and stabilized thereafter. The moisture content percentage, which showed an inverse relationship with density, declined rapidly during the first two years and reached a stable value in later years. The study suggested that the maturation process of newly emerged culms was rapid during the first two years, and stabilized after the third year in both species.
Keywords:cell walls; density; lignification; moisture content; non wood forest products; parenchyma; plant anatomy