Leaf Anatomy in Sansevieria (Agavaceae)

Abstract

Forty-nine taxa of Sansevieria were examined to provide the first detailed description of leaf anatomy in the genus, as well as to determine the cellular organization of the water-storage tissue present in the central mesophyll of all leaves. Leaf form ranges from flat through cylindrical, with varying degrees of xeromorphic characteristics, including cuticle thickness, stomatal depth, fiber content, and fiber cell development. Mesophyll in all species is divided into an outer region of chlorenchyma and a central region of colorless water-storage tissue. The water-storage tissue comprises a highly branched 3-dimensional network of living cells, among which are many dead, thin-walled water-storage cells. Species with more extreme xeromorphic characteristics tend to have a greater percentage of their water-storage tissue composed of water-storage cells. In 28 taxa, water-storage cells have spiral or reticulate wall bands. These taxa tend to be more xeromorphic. The wall bands may serve an important structural role in drought tolerance.

Elastic and collapsible: current understanding of cell walls in succulent plants

“…Studies on the cortex hydrenchyma in stems of Cactaceae ( Mauseth, 1995 ) and the hydrenchyma in leaves of Aloe ( Ahl et al , 2019 b ) have given the most detailed descriptions to date of collapsible cell walls in succulents. This type of cell wall has also been reported in succulent stems of Euphorbia (Euphorbiaceae) and Asclepiadoideae (Apocynaceae; Mauseth, 2004 b ), and in succulent leaves of Sansevieria ( Koller and Rost, 1988 a , b ) and Pyrrosia (Polypodiaceae; Ong et al , 1992 ). Although the presence of collapsible cell walls has not been systematically surveyed, histological images from an even broader body of research suggests that collapsible cell walls occur in many more succulent lineages: folding patterns can be observed in succulent tissues of Aizoaceae (e.g.…”

“…Most large succulent organs usually possess support tissues, such as hypodermis, fibres, and wood and bark from secondary growth ( Blunden, 1973 ; Koller and Rost, 1988 a ; Mauseth, 2004 a , b , 2006 ). There has been a growing interest in the support tissues and their cell walls in certain succulent lineages due to their adaptive and evolutionary relevance or their useful applications, such as the different types of wood of Cactaceae ( Vázquez-Sánchez et al , 2017 ; Reyes-Rivera et al , 2018 ; Maceda et al , 2019 ) and the sclerenchyma fibres of Agave (Asparagaceae; Ferreira et al , 2014 ; Hidalgo-Reyes et al , 2015 ).…”

“…In the notoriously drought-resistant genus Sansevieria (syn. Dracaena , Asparagaceae), many species exhibit secondary cell wall bands in the hydrenchyma ( Koller and Rost, 1988 a , b ). Similarly, wide-band tracheids occur in the vascular tissues of succulent organs in many genera of succulent families of the Caryophyllales, namely Cactaceae, Aizoaceae, Anacampserotaceae, and Didiereaceae; these tracheids have annular or helical secondary wall thickenings that extend deeply into the lumen ( Landrum, 2001 , 2006 ; Mauseth, 2004 c ).…”

“…However, the exact mechanism behind this highly regulated process is still largely unknown. Anatomical peculiarities of collapsible cell walls hint at the mechanism behind the folding process: in Sansevieria the collapsible walls in the hydrenchyma exhibit bands of secondary thickening ( Koller and Rost, 1988 a , 1988 b ), and it is possible that this ridged spatial patterning of stiffer and softer regions determines how the wall folds. However, most succulent tissues lack secondary wall thickening.…”

Indirect organogenesis for high frequency shoot regeneration of two cultivars of Sansevieria trifasciata Prain differing in fiber production

“…Differences in the chemical composition and morphology of the fibers in the two cultivars examined here seem to support the classification of very-soft fiber accession reported for S. trifasciata cv. Golden Hahnii 38 and may account for differences in thermal and mechanical properties, which have so far been analyzed for Lorentii but not Hahnii 1 , 39 , 40 . In S. cylindrica , the fibers have slightly lower cellulose and hemicellulose contents and a 50% less lignin than in S. ehrenbergii , which causes notable differences in the density, tensile strength, Young’s modulus and elongation at break values of the fibers (reviewed by Lokantara et al 41 ).…”