Stability of Leaf Variegation in Saintpaulia Ionantha During in Vitro Propagation and During Chimeral Separation of a Pinwheel Flowering Form

Abstract

Plants of the foliarly variegated cultivar Saintpaulia ionantha Tommie Lou and the florally variegated cultivar Candy Lou were regenerated through tissue culture from leaf sections, petal sections, and subepidermal tissue. This provided explants with derivatives of all histogen layers of the shoot apex, layers I and II only, and layers II and III only. Over 1,000 plants of Tommie Lou and Candy Lou were grown to flowering. A low level of phenotypic variation was observed, but in no case could this be attributed to the separation of genotypically distinct cell lines. The foliar variegation pattern of both cultivars was stable through in vitro propagation. In contrast, the chimeral components of the flower color pattern in Candy Lou separated during regeneration. These data demonstrate that Tommie Lou-type foliar variegation is not caused by periclinal chimerism and that all leaf cell layers possess the genetic information necessary to produce variegated foliage. The production of all green and all white plants from a radiation-induced periclinal chimera demonstrated that the system used could detect chimeral separation. These results support the contention that adventitious shoots in Saintpaulia almost always differentiate in vitro from a derivative(s) of a single histogen layer, and this layer is usually the LI.

In Vitro Segregation of Tetraploid and Octoploid Plantlets from Colchicine-induced Ploidy Chimeras in Echinacea purpurea L.

“…Segregation of chimeras into pure plants containing only one type of component cells is a long-established topic (Canli, 2003;Canli and Skirvin, 2008;Chua et al, 1981;Hall et al, 1986;Marcotrigiano et al, 1987;Skirvin, 1983, 1989;Ning et al, 2009;Peary et al, 1988;Rosu et al, 1995;Roy et al, 2001). The mechanism was primarily explained using the theory of the tunica-corpus pattern of the meristematic region described by Schmidt (1924) and later refined by Tilney-Bassett (1986, 1991.…”

Effects of the in vitro behavior of micropropagated plants on the stability of variegation in Yucca gloriosa, Phormium tenax, and Cordyline australis cultivars

“…Periclinal chimeras remain stable when propagation does not provoke the reorganization of cell layers (Marcotrigiano, 1997;Frank and Chitwood, 2016). Adventitious meristem formations generally arise from a single cell in many plants (Boertjes et al, 1968;Yang et al, 2017), often with only the participation of the L1 epidermal layer (Boertjes and Van Harten, 1985;Peary et al, 1988;Yang et al, 2017). Nevertheless, histological analyses revealed that all of the cell layers can be at the origin of an adventitious meristem, with the possibility of a multicellular origin, sometimes leading, even in small proportions, to variegated plants arising from adventitious regeneration (Marcotrigiano, 1986;Nabeshima et al, 2017).…”

Phenotypic variation during micropropagation of the chimeralRhododendron ?President Roosevelt?

“…In vitro segregation of the component genotypes of chimeral plants has been observed in several herbaceous micropropagation systems [4,6,7,8,16,18,21,22,28], with fewer reports on woody plants [5,24,30]. While Rhododendron micropropagation is well documented [1,2,3,9,10,11,12,13,14,15,17,23,25,26], whether multiplication proceeds by axillary or adventitious shoot growth has not been documented.…”