Structure, origin, development and senescence of colleters in Nerium indicum mill (N. odorum soland., Apocynaceae)
1989
Thomas, V. | Dave, Y. (Sardar Patel Univ., Vallabh Vidyanagar, Gujarat (India). Dept. of Biosciences)
Nerium indicum has adaxial basal colleters on each petiole, bract, bracteole, calyx and corolla. The colleters are finger-shaped sometimes lobed structures with tall heads on short stalks. The petiolar colleters are more abundant than those on the bract, bractole, calyx and corolla but their structure is similar. Meristematic activity in a small group of protodermal and hypodermal cells at the base of the developing leaf gives rise to the colleter that further differentiates by frequent anticlinal and periclinal divisions. Many of the colleters are vascularized, sometimes a layer of radially elongated cells is present beneath the epithelial cells. Senescence of a colleter begins when the leaves have either completed their growth or are still expanding. In senescent colleters, the central cell cytoplasm and nuclei are considerably reduced. Thin layer chromatography of the freshly harvested exudate of colleter shows the presence of rhamnose, glucose and arabinose sugars
显示更多 [+] 显示较少 [-]