Chimeric patterns in Juniperus chinensis ‘Torulosa Variegata’ (Cupressaceae) expressed during leaf and stem formation

Abstract

Juvenile leaves of the variegated Hollywood juniper, Juniperus chinensis 'Torulosa Variegata', have sectorial chimeras of variable widths and lengths. Sectors extend over several nodes often as small as 1/24 the circumference of the leaf. Other chimeras appear as light green to yellow streaks but are actually internal, dark green corpus sectors often occupying less than 1/20 of the cross sectional area of a leaf. On the basis of the sizes of these two types of sectors, there seems to be ideally about 168 founder cells comprising 63 tunica cells and 105 corpus cells; 49 of the latter are contiguous with the tunica and 66 are located deeper in the corpus. Similarly, sectoring in axillary branches of original chimeric sprays have the same types of sectoring. It is hypothesized that the outer rings of founder cells form two arcs of 12 cells around the stem apex, one for each of two leaves at a node of the decussate shoot, of a circumference of about 50 cells.

Costs and benefits of genetic heterogeneity within organisms

“…4 Sanders (1999); Money (2000); Peabody et al (2000); Stenlid (2000); Kuhn et al (2001). 5 Whitham & Slobodchikoff (1981); Jerling (1985); Ruth et al (1985); Klekowski (1988); Edwards et al (1990); Thomson et al (1991); Gill et al (1995); Szymkowiak & Sussex (1996); Marcotrigiano (1997Marcotrigiano ( , 2000; Korn (2002). 6 Grosberg (1988); Hughes (1989); Rinkevich & Shapira (1999); Barki et al (2002).…”

The marginal band, a new structural component of the developing angiosperm leaf

“…Recognition of the marginal meristem through computer simulation explains how leaf shape is determined. For a leaf to expand more laterally than longitudinally requires the margin to expand faster than internal tissue, an idea proposed for the emergence of a new leaf primordium from the stem apex (Korn, 2002). Simply put, marginal regions have to grow faster than internal regions otherwise marginal tissue will tear apart.…”

Positional cues regulate dorsal organ formation in the liverwort Marchantia polymorpha

“…Land plant development is characterized by apical growth, in which stem cells residing in the shoot apical meristem produce new tissues and organs, and changes in stem cell and apical function are linked to the origin of three-dimensional land plant forms and their subsequent diversification (reviewed in Harrison 2017;Moody 2020). Whilst bryophyte meristems are thought to have a single apical cell whose geometry and cleavage patterns determine organ position and plants' overall body plan (Harrison et al 2009;Parihar 1967), lycophyte and fern meristems have one to a few apical cells (Harrison and Langdale 2010;Harrison et al 2007;Sanders et al 2011), and seed plants have multicellular meristems (Korn 2001(Korn , 2002Poethig 1987;Poethig and Szymkowiak 1995).…”