Embryological Studies in the Orchidaceae. I. Gametophytes

Post-Pollination Ovule Development inDendrobiumOrchids. I. Introduction

“…:..,.,. This study as well as those of SwAMY (1949), PASTRANA andSANTOS (1931}, andNIIMOTO andSAGAWA (1961) indicate that the initiation of cell divisions in the placental ridges of Dendrobium depends upon pollination. Fruits of D. XJ.…”

“…The second division in the basal cell is transverse and gives rise to the middle and the suspensor initial cells. In Dendrobium, according to SWAMY (1949), the embryo is formed from divisions of the terminal and middle cells. The suspensor initial differentiates, without dividing, into a persisting vesicular structure at one end of the embryo.…”

Pollinium development in Spiranthes sinensis (Pers.) Ames.and Cymbidium pendulum SW: a comparative study

“…The mitotic divisions was asynchronous which may be due to weak cytoplasmic connections between the adjacent microspores (Figs 2e-h). A similar mode of male gametophyte development has been reported in some other orchids (Swamy 1949, Sood 1989, 1992, Gupta 2003, Aybeke 2012. In S. sinensis, the endothecial layers developed fibrous thickenings similar to Z. strateumatica (Kant and Bhanwra 2010), whereas in C. pendulum, middle layers developed fibrous thickenings that morphologically similar to those of endothecium as reported in most of the epiphytic orchids (Gupta 2003, Bhanwra et al 2006a.…”

“…Apostasioideae, Cypripedioideae, Vanilloideae, Orchidoideae and Epidendroideae based on the peculiarities of anther characteristics such as number and position of anther on the column, orientation, number and morphology of the pollinia, types of shedding units, pollen texture and sculpturing (Cameron et al 1999). But, earlier works on orchid embryology mainly focused on the development of female gametophyte and embryo (Swamy 1949, Bhanwra et al 2006a, Gurudeva and Govindappa 2008 and a little information is available on pollinium and pollen development. Therefore, the present research was undertaken to study the early anther development, anther wall differentiation and its associated changes, and pollinium development in Spiranthes sinensis (Pers.)…”

Cytogenetic Studies in the Genus Cymbidium

“…The research was probably initiated by Francini (1934) when he gave rough idiograms of the chromosome complements of two species of the genus. The comprehensive works of Duncan and MacLeod (1948aand b, 1949a, b and c, 1950a carried on this line of investigation.…”