Limits...
Revealing diversity in structural and biochemical forms of C4 photosynthesis and a C3-C4 intermediate in genus Portulaca L. (Portulacaceae).

Voznesenskaya EV, Koteyeva NK, Edwards GE, Ocampo G - J. Exp. Bot. (2010)

Bottom Line: Portulaca cryptopetala (clade Oleracea), an endemic species from central South America, was identified as a C(3)-C(4) based on its intermediate CO(2) compensation point and selective localization of glycine decarboxylase of the photorespiratory pathway in mitochondria of bundle sheath cells.The C(4) Portulaca species which were examined also have cotyledons with Kranz-type anatomy, while the stems of all species have C(3)-type photosynthetic cells.The results indicate that multiple structural and biochemical forms of C(4) photosynthesis evolved in genus Portulaca.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Anatomy and Morphology, V.L. Komarov Botanical Institute, Russian Academy of Sciences, Prof. Popov Street 2, 197376, St. Petersburg, Russia.

ABSTRACT
Portulacaceae is one of 19 families of terrestrial plants in which species having C(4) photosynthesis have been found. Representative species from major clades of the genus Portulaca were studied to characterize the forms of photosynthesis structurally and biochemically. The species P. amilis, P. grandiflora, P. molokiniensis, P. oleracea, P. pilosa, and P. umbraticola belong to the subgenus Portulaca and are C(4) plants based on leaf carbon isotope values, Kranz anatomy, and expression of key C(4) enzymes. Portulaca umbraticola, clade Umbraticola, is NADP-malic enzyme (NADP-ME)-type C(4) species, while P. oleracea and P. molokiniensis in clade Oleracea are NAD-ME-type C(4) species, all having different forms of Atriplicoid-type leaf anatomy. In clade Pilosa, P. amilis, P. grandiflora, and P. pilosa are NADP-ME-type C(4) species. They have Pilosoid-type anatomy in which Kranz tissues enclose peripheral vascular bundles with water storage in the centre of the leaf. Portulaca cf. bicolor, which belongs to subgenus Portulacella, is an NADP-ME C(4) species with Portulacelloid-type anatomy; it has well-developed Kranz chlorenchyma surrounding lateral veins distributed in one plane under the adaxial epidermis with water storage cells underneath. Portulaca cryptopetala (clade Oleracea), an endemic species from central South America, was identified as a C(3)-C(4) based on its intermediate CO(2) compensation point and selective localization of glycine decarboxylase of the photorespiratory pathway in mitochondria of bundle sheath cells. The C(4) Portulaca species which were examined also have cotyledons with Kranz-type anatomy, while the stems of all species have C(3)-type photosynthetic cells. The results indicate that multiple structural and biochemical forms of C(4) photosynthesis evolved in genus Portulaca.

Show MeSH
Electron microscopy of in situ immunolocalization of glycine decarboxylase (GDC) in chlorenchyma cells of P. oleracea (A, B), P. cryptopetala (D, E), and Sesuvium portulacastrum (G, H), and graphs showing the density of labelling for GDC in BS versus M mitochondria (right panels C, F, and I). (A, D, G) Immunolabelling of GDC in bundle sheath cell mitochondria. (B, E) Lack of immunolabelling for GDC in M cells of two Portulaca species, and (H) showing the presence of gold particles in M mitochondria in S. portulacastrum. (C, F, I) In all graphs the x-axis represents the number of gold particles per μm2 of mitochondrial area; for each cell type 10–60 cell fragments were used for counting. The horizontal lines near the base of the bars represent the level of background (number of particles per cell fragment area excluding mitochondria). BS, bundle sheath cell; Ch, chloroplast; M, mesophyll; Mt, mitochondria; PP, phloem parenchyma cell. Scale bars: 0.5 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC2921202&req=5

fig5: Electron microscopy of in situ immunolocalization of glycine decarboxylase (GDC) in chlorenchyma cells of P. oleracea (A, B), P. cryptopetala (D, E), and Sesuvium portulacastrum (G, H), and graphs showing the density of labelling for GDC in BS versus M mitochondria (right panels C, F, and I). (A, D, G) Immunolabelling of GDC in bundle sheath cell mitochondria. (B, E) Lack of immunolabelling for GDC in M cells of two Portulaca species, and (H) showing the presence of gold particles in M mitochondria in S. portulacastrum. (C, F, I) In all graphs the x-axis represents the number of gold particles per μm2 of mitochondrial area; for each cell type 10–60 cell fragments were used for counting. The horizontal lines near the base of the bars represent the level of background (number of particles per cell fragment area excluding mitochondria). BS, bundle sheath cell; Ch, chloroplast; M, mesophyll; Mt, mitochondria; PP, phloem parenchyma cell. Scale bars: 0.5 μm.

Mentions: In situ immunolabelling for GDC was examined in P. cryptopetala, P. oleracea, and the C3 species S. portulacastrum. Analysis of the immunolabelling distribution for anti-GDC antibody at the electron microscopy level shows that in the C4 species P. oleracea, gold particles are selectively localized in BS mitochondria (Fig. 5A); labelling in M mitochondria is very low, near background levels (Fig. 5B; see also the graph showing the density of gold particles per BS and M mitochondria in Fig. 5C). Similarly, in P. cryptopetala there is clear selective labelling for GDC in BS mitochondria (Fig. 5D–F). In comparison, in the C3 species S. portulacastrum, there is equivalent labelling of GDC in mitochondria of M and BS cells (Fig. 5G–I).


Revealing diversity in structural and biochemical forms of C4 photosynthesis and a C3-C4 intermediate in genus Portulaca L. (Portulacaceae).

Voznesenskaya EV, Koteyeva NK, Edwards GE, Ocampo G - J. Exp. Bot. (2010)

Electron microscopy of in situ immunolocalization of glycine decarboxylase (GDC) in chlorenchyma cells of P. oleracea (A, B), P. cryptopetala (D, E), and Sesuvium portulacastrum (G, H), and graphs showing the density of labelling for GDC in BS versus M mitochondria (right panels C, F, and I). (A, D, G) Immunolabelling of GDC in bundle sheath cell mitochondria. (B, E) Lack of immunolabelling for GDC in M cells of two Portulaca species, and (H) showing the presence of gold particles in M mitochondria in S. portulacastrum. (C, F, I) In all graphs the x-axis represents the number of gold particles per μm2 of mitochondrial area; for each cell type 10–60 cell fragments were used for counting. The horizontal lines near the base of the bars represent the level of background (number of particles per cell fragment area excluding mitochondria). BS, bundle sheath cell; Ch, chloroplast; M, mesophyll; Mt, mitochondria; PP, phloem parenchyma cell. Scale bars: 0.5 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2921202&req=5

fig5: Electron microscopy of in situ immunolocalization of glycine decarboxylase (GDC) in chlorenchyma cells of P. oleracea (A, B), P. cryptopetala (D, E), and Sesuvium portulacastrum (G, H), and graphs showing the density of labelling for GDC in BS versus M mitochondria (right panels C, F, and I). (A, D, G) Immunolabelling of GDC in bundle sheath cell mitochondria. (B, E) Lack of immunolabelling for GDC in M cells of two Portulaca species, and (H) showing the presence of gold particles in M mitochondria in S. portulacastrum. (C, F, I) In all graphs the x-axis represents the number of gold particles per μm2 of mitochondrial area; for each cell type 10–60 cell fragments were used for counting. The horizontal lines near the base of the bars represent the level of background (number of particles per cell fragment area excluding mitochondria). BS, bundle sheath cell; Ch, chloroplast; M, mesophyll; Mt, mitochondria; PP, phloem parenchyma cell. Scale bars: 0.5 μm.
Mentions: In situ immunolabelling for GDC was examined in P. cryptopetala, P. oleracea, and the C3 species S. portulacastrum. Analysis of the immunolabelling distribution for anti-GDC antibody at the electron microscopy level shows that in the C4 species P. oleracea, gold particles are selectively localized in BS mitochondria (Fig. 5A); labelling in M mitochondria is very low, near background levels (Fig. 5B; see also the graph showing the density of gold particles per BS and M mitochondria in Fig. 5C). Similarly, in P. cryptopetala there is clear selective labelling for GDC in BS mitochondria (Fig. 5D–F). In comparison, in the C3 species S. portulacastrum, there is equivalent labelling of GDC in mitochondria of M and BS cells (Fig. 5G–I).

Bottom Line: Portulaca cryptopetala (clade Oleracea), an endemic species from central South America, was identified as a C(3)-C(4) based on its intermediate CO(2) compensation point and selective localization of glycine decarboxylase of the photorespiratory pathway in mitochondria of bundle sheath cells.The C(4) Portulaca species which were examined also have cotyledons with Kranz-type anatomy, while the stems of all species have C(3)-type photosynthetic cells.The results indicate that multiple structural and biochemical forms of C(4) photosynthesis evolved in genus Portulaca.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Anatomy and Morphology, V.L. Komarov Botanical Institute, Russian Academy of Sciences, Prof. Popov Street 2, 197376, St. Petersburg, Russia.

ABSTRACT
Portulacaceae is one of 19 families of terrestrial plants in which species having C(4) photosynthesis have been found. Representative species from major clades of the genus Portulaca were studied to characterize the forms of photosynthesis structurally and biochemically. The species P. amilis, P. grandiflora, P. molokiniensis, P. oleracea, P. pilosa, and P. umbraticola belong to the subgenus Portulaca and are C(4) plants based on leaf carbon isotope values, Kranz anatomy, and expression of key C(4) enzymes. Portulaca umbraticola, clade Umbraticola, is NADP-malic enzyme (NADP-ME)-type C(4) species, while P. oleracea and P. molokiniensis in clade Oleracea are NAD-ME-type C(4) species, all having different forms of Atriplicoid-type leaf anatomy. In clade Pilosa, P. amilis, P. grandiflora, and P. pilosa are NADP-ME-type C(4) species. They have Pilosoid-type anatomy in which Kranz tissues enclose peripheral vascular bundles with water storage in the centre of the leaf. Portulaca cf. bicolor, which belongs to subgenus Portulacella, is an NADP-ME C(4) species with Portulacelloid-type anatomy; it has well-developed Kranz chlorenchyma surrounding lateral veins distributed in one plane under the adaxial epidermis with water storage cells underneath. Portulaca cryptopetala (clade Oleracea), an endemic species from central South America, was identified as a C(3)-C(4) based on its intermediate CO(2) compensation point and selective localization of glycine decarboxylase of the photorespiratory pathway in mitochondria of bundle sheath cells. The C(4) Portulaca species which were examined also have cotyledons with Kranz-type anatomy, while the stems of all species have C(3)-type photosynthetic cells. The results indicate that multiple structural and biochemical forms of C(4) photosynthesis evolved in genus Portulaca.

Show MeSH