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
Light micrographs showing cross-sections of cotyledons (A, D, G, J, M, P) and young stems (B, E, H, K, N, Q), and scanning electron microscopy of stem epidermis (C, F, I, L, O, R) for six Portulaca species: P. umbraticola (A–C), P. oleracea (D–F), P. grandiflora (G–I), P. amilis (J–L), P. cf. bicolor (M–O), and P. cryptopetala (P–R). CP, cortex parenchyma; H, hypoderm; VB, vascular bundle. Scale bars: 200 μm for cotyledons (left column); 100 μm for stem cross-sections (middle column); 500 μm for C, F, I, L, R, and 400 μm for O for stem epidermis (right column).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig7: Light micrographs showing cross-sections of cotyledons (A, D, G, J, M, P) and young stems (B, E, H, K, N, Q), and scanning electron microscopy of stem epidermis (C, F, I, L, O, R) for six Portulaca species: P. umbraticola (A–C), P. oleracea (D–F), P. grandiflora (G–I), P. amilis (J–L), P. cf. bicolor (M–O), and P. cryptopetala (P–R). CP, cortex parenchyma; H, hypoderm; VB, vascular bundle. Scale bars: 200 μm for cotyledons (left column); 100 μm for stem cross-sections (middle column); 500 μm for C, F, I, L, R, and 400 μm for O for stem epidermis (right column).

Mentions: There is vast variation in the distribution of VBs in leaves of the Portulaca species studied with Kranz-type chlorenchyma; however, the cotyledons, except for P. cf. bicolor, all have Atriplicoid-like anatomy with VBs distributed in one lateral plane (Fig. 7, left column, not shown for P. molokiniensis and P. pilosa). In most of the species studied, the VBs are surrounded by two layers of chlorenchyma cells, with mostly one layer of colourless hypodermal cells on the abaxial side of the cotyledon (Fig. 7A, D, G, J), except for P. umbraticola, which has hypodermal layers on both sides of the cotyledon (Fig. 7A). In P. cf. bicolor, cotyledons (Fig. 7M) have the same structure as leaves (Fig. 2Q): the VBs are located adjacent to the adaxial epidermis of the cotyledon, with reduced development of Kranz on the lower side of the VBs, and there are two layers of colourless hypodermal cells on the abaxial side.


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)

Light micrographs showing cross-sections of cotyledons (A, D, G, J, M, P) and young stems (B, E, H, K, N, Q), and scanning electron microscopy of stem epidermis (C, F, I, L, O, R) for six Portulaca species: P. umbraticola (A–C), P. oleracea (D–F), P. grandiflora (G–I), P. amilis (J–L), P. cf. bicolor (M–O), and P. cryptopetala (P–R). CP, cortex parenchyma; H, hypoderm; VB, vascular bundle. Scale bars: 200 μm for cotyledons (left column); 100 μm for stem cross-sections (middle column); 500 μm for C, F, I, L, R, and 400 μm for O for stem epidermis (right column).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig7: Light micrographs showing cross-sections of cotyledons (A, D, G, J, M, P) and young stems (B, E, H, K, N, Q), and scanning electron microscopy of stem epidermis (C, F, I, L, O, R) for six Portulaca species: P. umbraticola (A–C), P. oleracea (D–F), P. grandiflora (G–I), P. amilis (J–L), P. cf. bicolor (M–O), and P. cryptopetala (P–R). CP, cortex parenchyma; H, hypoderm; VB, vascular bundle. Scale bars: 200 μm for cotyledons (left column); 100 μm for stem cross-sections (middle column); 500 μm for C, F, I, L, R, and 400 μm for O for stem epidermis (right column).
Mentions: There is vast variation in the distribution of VBs in leaves of the Portulaca species studied with Kranz-type chlorenchyma; however, the cotyledons, except for P. cf. bicolor, all have Atriplicoid-like anatomy with VBs distributed in one lateral plane (Fig. 7, left column, not shown for P. molokiniensis and P. pilosa). In most of the species studied, the VBs are surrounded by two layers of chlorenchyma cells, with mostly one layer of colourless hypodermal cells on the abaxial side of the cotyledon (Fig. 7A, D, G, J), except for P. umbraticola, which has hypodermal layers on both sides of the cotyledon (Fig. 7A). In P. cf. bicolor, cotyledons (Fig. 7M) have the same structure as leaves (Fig. 2Q): the VBs are located adjacent to the adaxial epidermis of the cotyledon, with reduced development of Kranz on the lower side of the VBs, and there are two layers of colourless hypodermal cells on the abaxial side.

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