Leaf morpho-anatomical diversity in Echeveria aff. gigantea (Crassulaceae)

Abstract

<p class="Normal1"><strong>Background.</strong> Distinguishing species and populations in Crassulaceae is challenging because of the morphological variability and inter-specific hybridization. Currently our understanding of the morphological and anatomical features in <em>Echeveria</em> is poor, and therefore it is difficult to delimit species, and morphotypes within the species. </p><p class="Normal1"><strong>Question.</strong> Our objective was to describe the foliar anatomy and the shape of accessions in <em>E. gigantea.</em> We used <em>E. gibbiflora</em>, another species in the series as a comparison group. Comparing the two species allowed us to evaluate the relationship between anatomy and morphology in <em>E. gigantea</em>.</p><p class="Normal1"><strong>Methods. </strong>We performed a survey of anatomical features in seven accessions of <em>E. gigantea</em>, and one accession of <em>E. gibbiflora</em>. We obtained epidermal prints, leaf sections, performed geometric and morphometric analyses.</p><p class="Normal1"><strong>Results. </strong>We found that 65 % of the anatomical traits are heterogeneous among the taxonomic units. Our analysis showed that <em>E. gibbiflora</em> and some <em>E. gigantea </em>accessions share extensive anatomical similarities. There was variation within the <em>E. gigantea</em>, suggesting that at least one of the accessions is an independent taxonomic group. The traits with the largest contribution to variation between the groups were related to the epidermis, the hypodermis, the type of vascular bundles and the collenchyma associated to the vascular bundles. In addition we quantified the variation in leaf shape. Interestingly, we found correlations between the organ shape and anatomical traits.</p><p class="normal"><strong>Conclusion. </strong>These analyses provide information about traits towards the morpho-anatomical definition of <em>E. gigantea</em> variation and suggest developmental correlation yet to be explained.</p>

Echeveria Leaf Morpho-Anatomical Analysis and Its Implications for Environmental Stress Conditions

“…This study observed that E. 'Brave' and E. 'Peerless' had shorter occlusive cells in the adaxial surface. Plants with shorter occlusive stomata on the abaxial surface than on the adaxial surface are often found in rocky regions with deficient annual precipitation and high annual temperatures [39]. Likewise, plants with small stomata size and low stomata frequency distribution indicate they can prevent water loss in semi-arid areas [74].…”

“…According to Ogburn and Edwards [84], succulent plants are commonly found to form a 3D arrangement. Furthermore, Sandoval-Zapotitla et al [39] suggest that this type of broadly branched vascular system allows for faster and more efficient transmission of water to all mesophyll cells, allowing for an adaptive advantage for various habitats, whether under low rainfall conditions or high temperature [85]. In addition, most of the cultivars had a collateral type of vascularization commonly observed in succulent plants [86].…”

“…The plants of this genus are favored for cultivation with various applications due to their attractive geometrical features and ability to thrive over the long term with minimal care, even in stressful conditions [35][36][37][38]. Echeveria is widely hybridized to meet the demands of floricultural markets and has numerous cultivars as they are easy to cross with related or non-related species [34], which results in homoplastic morphology [39]. Although these plants have similar morphology, they may cope differently within varying physiological conditions, and those with different morphology may often have comparable water-use efficiency [8,36].…”

Echeveria (Crassulaceae): Potencial para la mejora genética como ornamental

“…La amplia diversidad, facilidad de hibridación interespecífica e intergenérica, la poca investigación e imprecisiones en taxonomía han propiciado que, en ocasiones, haya especies que se identifiquen erróneamente por ser híbridas o por una fuerte variación ambiental. Para demostrar la amplia diversidad fenotípica que puede tener una especie, Sandoval-Zapotitla et al (2019) desarrollaron una investigación relacionada con la diversidad morfoanatómica foliar de Echeveria aff. gigantea, en la cual encontraron que entre seis accesiones de la especie y 32 variables cuantificadas, un 65% de los rasgos anatómicos resultaron ser variables.…”

Variación de caracteres epidérmico-foliares de Agave salmiana subsp. salmiana (Asparagaceae) en el centro de México

“…Diversos estudios han mostrado la utilidad de los estudios anatómicos en el conocimiento de la variación infraespecífica en plantas y su relación con el ambiente (Ackerly et al 2002, McDonald et al 2003, Reyes et al 2005, Martínez-Quezada et al 2016, Jiménez-Noriega et al 2017, Martínez-Valverde 2019, Sandoval-Zapotitla et al 2019. Este enfoque a la fecha no ha sido abordado para el género Agave y sólo algunos estudios reportan aspectos generales de su anatomía foliar, donde se ha descrito la cutícula y superficie foliar de unas pocas especies (Gentry & Sauck 1978, Willmer & Pallas 1983, Nobel 1988.…”