Endoreduplication level affects flower size and development by increasing cell size in Phalaenopsis and Doritaenopsis

Evolutionary and functional potential of ploidy increase within individual plants: somatic ploidy mapping of the complex labellum of sexually deceptive bee orchids

“…However, all of these previous orchid studies (1) treated each organ of the flower as a homogeneous entity and (2) relied upon indirect estimates of nucleus size obtained via flow cytometry of homogenized tissue samples, rather than through direct microscopic observation of individual cells (cf. Mishiba et al, 2001;Lim and Loh, 2003;Yang and Loh, 2004;Barow and Jovtchev, 2007;Chen et al, 2011;Teixeira et al, 2014;Travnicek et al, 2015;Ho et al, 2016;reviewed by Hribova et al, 2016). Such studies are unable to distinguish between the two contrasting modes of endoreplication (endomitosis and endocycling), though they do offer the newly recognized advantage of being able to detect all but the most subtle cases of PPE.…”

“…Unsurprisingly, the bulk of research into endoreplication in plants has been conducted on that most academically ubiquitous of species, Arabidopsis thaliana (Galbraith et al, 1991, et seq.). Greater frequency and/or number of cycles of endopolyploidy have been shown to increase organ size, not only in Arabidopsis but also in the model epidendroid orchid Phalaenopsis (Ho et al, 2016). Indeed, phenotypic expression of endoreplication is not confined to mere size differences; for example, the complexity of each unicellular but multiply branched trichome that adorns an Arabidopsis leaf is positively correlated with, and potentially dictated by, the number of endoreplications undergone by its nucleus (Folkers et al, 1997;Traas et al, 1998).…”

“…There may even be a requirement for a degree of environmental predictivity by the affected cell, as current evidence suggests that endocycles determine the final size and shape of the affected cell but cease early in cell development, before the large central vacuole has formed and certainly before the bulk of cell expansion has occurred. Thus, on the basis of their observations on the model epidendroid orchids Phalaenopsis and Oncidium, Ho et al (2016;see also Lee et al, 2004) argued that once endoreplication in an orchid flower ceases, so does its ability to further expand through cell division. Traas et al (1998, p. 500) therefore warned that the correlation between nucleus size and cell size/complexity would most likely be clearest in those plant cell types that are the least physically constrained, such as trichomes and root hairs, noting that 'in expanding tissues, growth of neighbouring cells must be tightly coordinated in order to avoid local distortions of tissues'.…”

An Overview of Orchid Protocorm-Like Bodies: Mass Propagation, Biotechnology, Molecular Aspects, and Breeding

“…This is because although genera have a greater genetic and morphological contribution to commercial plants, most commercial flower production of these genera occurs through the production of hybrids from interspecific crosses, which include the use of crosses between species of the same genus, but also species of different genera (intergeneric hybrids) [9]. An example of this case is the very frequent use of Doritis in crossings with Phalaenopsis, generating the hybrid genus known as Doritaenopsis [10,11]. Nevertheless, commercially these hybrids are all called Phalaenopsis because considering the morphological similarity and commercialization value, there is no commercial justification for separation into two classes.…”