Competition and Accommodation Between Apical Layers and Their Derivatives in the Ontogeny of Chimeral Shoots of Pelargonium X Hortorum

Abstract

Two mutant plastogenes in all possible chimeral combinations were followed in Pelargonium X hortorum Bailey (geranium) shoots. The part of stem, leaf, or other structure derived from each apical layer was clearly apparent on a cell to cell basis. Shoots typically were composed of derivatives of three apical layers but we found derivatives of as many as four apical layers in some leaves and of five layers in some stems. In chimeras with one of the mutants, Dpl W1, the amount of tissue derived from the various apical layers was the same, whether the layer was mutant or wild type. We suggest that there are independent apical layers and cell lineages derived from them in nonchimeral shoots, and that their contribution in normal ontogeny is like that of the layers in Dpl W1 chimeras. In chimeras carrying the second mutant, Dpl W2, there was much less tissue derived from mutant than from wild‐type apical layers. The phenotypic expression of the plastogenes was unchanged by their transmission through male or female gametes. Comparisons of the ontogeny of geranium plants carrying the W1 or W2 mutant suggested that, while there was competition between the apical layers and between their derivatives, the genome imposed a definite harmonious interaction or accommodation which led to a final normal morphology of all plant parts and organs through quite different ontogenetic pathways.

Cell Lineage Dynamics in Stratified Shoot Apical Meristems

“…the morphology, developmental coordination, and physiological harmony of the organism? It appears that plants, and other modular organisms, have mechanisms that coordinate the proliferation and differentiation from different cell lineages, resulting in an integrated and harmonious higher-level unit (Szymkowiak, 1996), or as Steward et al (1974) conclude in their work on the ontogeny of chimeric Pelargonium:…”

SMRT sequencing analysis reveals the full-length transcripts and alternative splicing patterns in Ananas comosus var. bracteatus

“…bracteatus is cultivated commercially as an important ornamental plant for its colourful chimeric leaves and red fruit. A chimeric leaf can be used as a marker in breeding (Burge, Morgan & Seelye, 2002), and it is an optimal material for the study of plant tissue and organ formation and development (Satina, Blackeslee & Avery, 1940; Stewart, Semeniuk & Dermen, 1974) as well as the interaction between cells (Stegemann & Bock, 2009). Limited genomic information is available.…”

Cell lineage and its consequences in higher plants

“…The final shape of the organ is therefore 'self-correcting' and not simply the sum of the constituent cell divisions. This is exemplified particularly well by periclinal chimeras containing a visible somatic mutation (called W,) that slows growth (Stewart et a/., 1974). In W, periclinal chimeras, the slowed growth of the mutant cells is compensated for by normal cells in adjacent lineages such that the final shape is indistinguishable from wild-type.…”