Developmental and Structural Section
Prabha, Venkataramaiah .
Ultracytochemical localization of adenosine tri-phosphatase in the ray parenchyma with reference to heartwood formation in Azadirachta indica A.Juss.
In the present investigation the distribution pattern of Adenosine tri-phosphatase in different zones of wood during heartwood formation in Azadirachata indica , has been studied at ultrastructural level. ATPase localization was observed to be mainly associated with plasma membrane, in the network of the leucoplast, on the outer membrane of mitochondria and vesicles in the ray parenchyma cells of outer, middle and inner sapwoods. In the inner sapwood, intense reaction product was seen in association with the tonoplast of the vacuole. Intense reaction product was observed in the intercellular spaces of ray parenchyma cells of outer sapwood, and it gradually decreased towards the transition zone. Less reaction product was observed in the intercellular spaces of the ray parenchyma cells in the transition zone. Pit cavities showed intense reaction product in the sapwood region and in the transition zone reaction product was comparatively less. In the inner sapwood, some corroding starch grains were observed to be in close proximity of the pit cavities which show intense ATPase activity. Pit cavities in the transition zone showed enzyme activity associated with the intruding starch grains. Intense reaction product was observed on the membrane of lipid droplets which are associated with vesicles.Senescence of the parenchyma cells in the transition zone is indicated by : a)cytoplasm becomes dark scanty, and organelles are adpressed to the cell wall along with it, b)presence of a large central vacuole with granular electron opaque substance probably phenol c)Loss in the enzyme activity observed in the organelles, pit cavities, plasma membrane, and intercellular spaces.
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1 - Centre for postgraduate studies and research in botany, Botany, G.T.P. College campus, Nandurbar, Maharashtra, 425412, India
Presentation Type: Poster
Location: Salon C, D & E - Gov Ballroom/Hilton
Date: Tuesday, August 16th, 2005
Time: 12:30 PM