Anatomy and Histochemistry of the Roots and Shoots in the Aquatic Selenium Hyperaccumulator Cardamine hupingshanensis (Brassicaceae)

Abstract

The perennial selenium (Se) hyperaccumulator Cardamine hupingshanensis (Brassicaceae) thrives in aquatic and subaquatic Se-rich environments along the Wuling Mountains, China. Using bright-field and epifluorescence microscopy, the present study determined the anatomical structures and histochemical features that allow this species to survive in Se-rich aquatic environments. The roots of C. hupingshanensis have an endodermis with Casparian walls, suberin lamellae, and lignified secondary cell walls; the cortex and hypodermal walls have phi (Φ) thickenings; and the mature taproots have a secondary structure with a periderm. The stems possess a lignified sclerenchymal ring and an endodermis, and the pith and cortex walls have polysaccharide-rich collenchyma. Air spaces are present in the intercellular spaces and aerenchyma in the cortex and pith of the roots and shoots. The dense fine roots with lignified Φ thickenings and polysaccharide-rich collenchyma in the shoots may allow C. hupingshanensis to hyperaccumulate Se. Overall, our study elucidated the anatomical features that permit C. hupingshanensis to thrive in Se-rich aquatic environments.

Phenotypic Plasticity in the Structure of Fine Adventitious Metasequoia glyptostroboides Roots Allows Adaptation to Aquatic and Terrestrial Environments

“…Lignified phi (Φ) thickenings have been recorded in the inner cortex adjacent to the endodermis in M. milleri [4] and are considered similar to the endodermis in the roots of C. lanceolata , M. glyptostroboides , and other gymnosperm species [9,14,15]. More broadly, lignified Φ thickenings have been reported in the root cortices of several species, including the gymnospermous Ginkgo biloba [13] and C. lanceolata [14], and the angiospermous Pyrus malus [16], Brassica napus , B. oleracea [17,18], Myrica rubra [19], and Cardamine hupingshanensis [20].…”

Morphological and anatomical adaptations to dry, shady environments in Adiantum reniforme var. sinense (Pteridaceae)

“…sinense , the adventitious roots, the rhizomes, and the leaf axes all had an endodermis with the following histochemical features; Casparian bands and suberin lamellae surrounded by sclerenchyma layers. These characteristics tend to vary distinctly across tissues and organs in almost all other vascular plants ( Ogura, 1972 ; Fahn, 1990 ; Lersten, 1997 ; Enstone, Peterson & Ma, 2003 ; Evert, 2006 ; Yang et al, 2011 , 2014 , 2019a , 2019b , 2019c , 2020 ; Zhang et al, 2017 ; Zhang, Yang & Seago, 2018 ; Crang, Lyons-Sobaski & Wise, 2018 ; Xiang et al, 2019 ). Displaying alike to A. reniforme var.…”

“…and the epiphytic Pleopeltis macrocarpa possess an endodermis and a sclerenchyma layer around the vascular bundles throughout the plant ( Wetzel et al, 2017 ; De los Ángeles Lagoria et al, 2018 ). The endodermis and the sclerenchyma layers support and protect the bodies of vascular plants such as ferns, gymnosperms, and angiosperms ( Fahn, 1990 ; Lersten, 1997 ; Enstone, Peterson & Ma, 2003 ; Evert, 2006 ; Yang et al, 2011 , 2014 , 2019a , 2019b , 2019c , 2020 ; Crang, Lyons-Sobaski & Wise, 2018 ; Zhang et al, 2017 ; Zhang, Yang & Seago, 2018 ; Xiang et al, 2019 ). The presence of these structures suggested that A. reniforme var.…”

“…The presence of these structures suggested that A. reniforme var. sinense would survive in dry cliff environments ( Chapple & Peterson, 1987 ; Lersten, 1997 ; Yang et al, 2011 , 2014 , 2019a , 2019b , 2019c , 2020 ; Neira et al, 2017 ; Wetzel et al, 2017 ; Zhang et al, 2017 ; Zhang, Yang & Seago, 2018 ; De los Ángeles Lagoria et al, 2018 ; Xiang et al, 2019 ).…”

“…Moreover, the morphologies of sun and shade plants are obviously different ( Boardman, 1977 ; Nasrulhaq-Boyce & Mohamed, 1987 ; Givnish, 1988 ; Santos-Silva, Mastroberti & De Araujo Mariath, 2011 ), the leaves of shade plants are large, with large cells, few mesophyll tissues, and decreased stomatal and vein densities ( Ribeiro, Santos & Moraes, 2007 ; Zhang & Wu, 2013 ; Neira et al, 2017 ; Dematteis et al, 2019 ; Shah et al, 2019 ; Baer, Wheeler & Pittermann, 2020 ). In ferns, gymnosperms, and angiosperms, the endodermis or circumendodermal band and the exodermis act as barriers, which restrict water-solute exchange, reduce oxygen loss after submersion, and terrestrial environments ( Ogura, 1972 ; Lersten, 1997 ; Enstone, Peterson & Ma, 2003 ; Hernandez-Hernandez et al, 2012 ; Geldner, 2013 ; Xiang et al, 2019 ; Yang et al, 2011 , 2014 , 2019a , 2019b , 2019c , 2020 ; Zhang et al, 2017 ; Zhang, Yang & Seago, 2018 ).…”