Unique photosynthetic phenotypes inPortulaca(Portulacaceae): C₃-C₄intermediates and NAD-ME C₄species with Pilosoid-type Kranz anatomy

Abstract

Portulacaceae shows great diversity in C4 photosynthetic phenotypes: all species in clade Cryptopetala are C3-C4 intermediates, while clade Pilosa has a unique anatomical form of Kranz with diversity in C4 biochemistry.

The Development of Crassulacean Acid Metabolism (CAM) Photosynthesis in Cotyledons of the C4 Species, Portulaca grandiflora (Portulacaceae)

“…The research presented here indicated it was apparent that the C 4 pathway was well developed in 10 days old cotyledons based on the anatomy and physiology. The leaf anatomy of the cotyledons showed a well-developed Kranz C 4 anatomy as found previously in the genus Portulaca [23]. P. grandiflora cotyledons displayed an Atriplicoid-type anatomy where the vascular bundles are in one plane of the leaf.…”

“…Research has been performed on the physiological and structural development of C4 photosynthesis in cotyledons of the Portulaca but little of CAM development in these C4 species [23]. The research presented here indicated it was apparent that the C4 pathway was well developed in 10 days old cotyledons based on the anatomy and physiology.…”

C4photosynthesis and transition of Kranz anatomy in cotyledons and leaves ofTetraena simplex

“…Biochemical differences observed between cotyledons and leaves of T. simplex may also reflect enhancement of ultrastructural characteristics supporting NAD-ME subtype C 4 photosynthetic metabolism. In both organs, BS cells have numerous centripetally positioned granal chloroplasts and numerous large mitochondria, as reported in other NAD-ME C 4 species (Voznesenskaya et al, 1999(Voznesenskaya et al, , 2010(Voznesenskaya et al, , 2017Yoshimura et al, 2004;Muhaidat et al, 2007;Akhani et al, 2008;Edwards and Voznesenskaya, 2011;Koteyeva et al, 2011;Muhaidat and McKown, 2013). BS chloroplasts in leaves of T. simplex have greater development of grana (indicated by thylakoid stacking and granal index) compared to their counterparts in cotyledons, whereas thylakoid stacking in M chloroplasts remains relatively unchanged.…”

“…While comprehensive anatomical and biochemical assessments have focused largely on the Chenopodiaceae s.s. (Edwards and Voznesenskaya, 2011;Freitag and Kadereit, 2014 and references therein), Portulacaceae (Voznesenskaya et al, 2010(Voznesenskaya et al, , 2017Ocampo et al, 2013), Cleomaceae (Koteyeva et al, 2011), and Aizoaceae (Muhaidat and McKown, 2013;Bohley et al, 2015), many other C 4 eudicot lineages remain to be studied more thoroughly. Arid habitats of the Middle East possess a high diversity of C 4 eudicots offering an opportunity for further discoveries (Muhaidat et al, 2007).…”

Exploring C4–CAM plasticity within the Portulaca oleracea complex

“…Facultative CAM was shown to occur in species belonging to the six phylogenetic clades of Portulaca, some of which performing CAM-cycling when water is deprived [10][11][12][13][14][15][16] . In addition to this complex scenario, different decarboxylating systems occur in Portulaca, with NADP-malic enzyme (ME) and NAD-ME representatives such as P. grandiflora and P. oleracea, respectively 17,18 .…”