New Structural/Biochemical Associations in Leaf Blades of C4 Grasses (Poaceae)

1987 ◽  
Vol 14 (4) ◽  
pp. 403 ◽  
Author(s):  
HDV Prendergast ◽  
PW Hattersley ◽  
NE Stone
Keyword(s):  
Malic Enzyme ◽  
Cell Walls ◽  
Panicum Virgatum ◽  
Structural Features ◽  
Grass Species ◽  
Vascular Bundles ◽  
Carbon Reduction ◽  
Photosynthetic Carbon ◽  
Pep Carboxykinase ◽  
Photosynthetic Carbon Reduction

Forty-three previously uninvestigated, mainly Australian, grass species (Poaceae) were assayed for activities of C4 acid decarboxylating enzymes (NADP-malic enzyme, NADP-ME; NAD-malic enzyme, NAD-ME; PEP carboxykinase, PCK). Twenty-five species exhibit long-established ('classical') associations between C4 type and structural features of leaf blade vascular bundles. However, Panicum virgatum and Triraphis mollis are NAD-ME species with structure like that of 'classical' PCK species. Seven Enneapogon species and Triodia scariosa are NAD-ME but are structurally intermediate between 'classical' NAD-ME and PCK species. Alloteropsis semialata (R.Br.) Hitch. is PCK, the first recorded non-NADP-ME XyMS - species, and Pheidochloa gracilis S.T. Blake and five Eriachne species are the first known XyMS+ NADP-ME species, with either centripetal or centrifugal/peripheral PCR (photosynthetic carbon reduction, or Kranz) cell chloroplasts. A suberised lamella is absent from the PCR cell walls of all species with an even PCR bundle sheath outline, irrespective of C4 type, as well as from NADP-ME Aristida, Eriachne and Pheidochloa; it is present in all other species with an uneven outline and centrifugal/peripheral chloroplasts. Pheidochloa gracilis and Eriachne spp. have unusually well-developed grana in PCR cell chloroplasts for NADP-ME species. This new-found structural/biochemical diversity is discussed in relation to high [CO2] maintenance in PCR cells.

Geographical Distribution of C4 Acid Decarboxylation Types and Associated Structural Variants in Native Australian C4 Grasses (Poaceae)

1989 ◽  
Vol 37 (3) ◽  
pp. 253 ◽  
Author(s):  
HDV Prendergast
Keyword(s):  
Geographical Distribution ◽  
Malic Enzyme ◽  
Cell Walls ◽  
Summer Rainfall ◽  
Carbon Reduction ◽  
High Soil Moisture ◽  
Historical Factors ◽  
Soil Moisture Availability ◽  
Pep Carboxykinase ◽  
Photosynthetic Carbon Reduction

The native Australian C4 grass (Poaceae) flora is estimated to comprise 347 (57%) NADP-ME (NADP- malic enzyme), 193 (32%) NAD-ME (NAD-malic enzyme), and 65 (11%) PCK (PEP carboxykinase) type species. All C4 types are best represented in northern tropical Queensland, within the megatherm seasonal (summer) rainfall bioclimate of Nix. NADP-ME species are numerically dominant in 48 out of 73 State and Territory subdivisions, including 23 wholly or partly within the megathermlmesotherm arid bioclimate which closely corresponds to the arid and semiarid zones covering c. 80% of Australia. NAD-ME species numbers are proportionately at their highest in this bioclimate; PCK species may be the most dependent there on high soil moisture availability. The extent of the megatherm seasonal bioclimate is parallelled by the distribution of most PCK species and of many species of all C4 types with a suberised lamella in the cell walls of their 'photosynthetic carbon reduction' (or Kranz) tissue. Whilst the physiological reasons for these correlations are unknown, it is clear that C4 type alone is neither the sole determinant of geographical distribution nor necessarily always an adaptation to a particular bioclimatic regime. Taxonomic, ecological and historical factors in relation to C4 type distribution are discussed.

Comparison of photosynthetic carbon reduction (Kranz) cells having different ontogenetic origins in the C4 NADP – malic enzyme grass Arundinella hirta

1990 ◽  
Vol 68 (6) ◽  
pp. 1222-1232 ◽  
Author(s):  
Nancy G. Dengler ◽  
Ronald E. Dengler ◽  
Douglas J. Grenville
Keyword(s):  
Cell Walls ◽  
Vascular Tissue ◽  
Cell Types ◽  
Bundle Sheath ◽  
Carbon Reduction ◽  
Bundle Sheath Cells ◽  
Photosynthetic Carbon ◽  
Arundinella Hirta ◽  
Photosynthetic Carbon Reduction ◽  
Sheath Cells

The C4 grass Arundinella hirta is characterized by unusual leaf blade anatomy: photosynthetic carbon reduction takes place both within the chlorenchymatous bundle sheath cells of the longitudinal veins and within longitudinal strands of "distinctive cells" that form part of the leaf mesophyll and are often completely isolated from vascular tissue. Although they are equivalent physiologically, these two cell types have different ontogenetic origins: bundle sheath cells are delimited from procambium early in leaf development, whereas distinctive cells differentiate from ground meristem at a later developmental stage. Although the two cell types share numerous cytological features (large chloroplasts with reduced grana, thick cell walls with a suberin lamella), we also found significant differences in cell lengths, length to width ratios, cell cross-sectional areas, organelle numbers per cell cross section, phenol content of the cell walls, and numbers of pit fields in the longitudinal cell walls. The size and shape of bundle sheath cells are likely a direct consequence of procambial origin. The thicker walls of bundle sheath cells (in major veins) and their greater lignification may reflect the inductive effect of cell differentiation in the proximity of sclerenchyma and vascular tissues. Differences between major and minor vein bundle sheath cells may reflect differences in the timing of initiation of procambial strands. Our analysis of cell wall characteristics has also shown the presence of numerous primary pit fields in the transverse walls between adjacent distinctive cells in a file; plasmodesmata in these pit fields form a pathway for longitudinal symplastic transport not previously known to exist.

Occurrence of the Suberized Lamella in Leaves of Grasses of Different Photosynthetic Type. II. In Herbarium Material

1984 ◽  
Vol 32 (5) ◽  
pp. 465 ◽  
Author(s):  
PW Hattersley ◽  
S Perry
Keyword(s):  
Malic Enzyme ◽  
Cell Walls ◽  
Large Scale ◽  
Herbarium Specimens ◽  
Mestome Sheath ◽  
Carbon Reduction ◽  
Suberized Lamella ◽  
Living Material ◽  
Photosynthetic Type ◽  
Pep Carboxykinase

Dead air-dried leaves have been conventionally prepared for transmission electron microscopy to ascertain if the occurrence of a suberized lamella in cell walls can be detected. Our species sample includes representatives of all known photosynthetic types within the Poaceae (viz. C3, C4 NAD-malic enzyme type, C4 NADP-malic enzyme type and PEP carboxykinase type). Each photosynthetic type exhibits a characteristic pattern of suberized lamella occurrence in mestome sheath and/or 'photosynthetic carbon reduction' (PCR or 'Kranz') cell walls, consistent with that in fixed living material. Plasmodesmatal structure, and even on occasion chloroplast structure, is remarkably well preserved. Leaves from herbarium specimens, therefore, could be used to assign C4 species to their C4 acid decarboxylation type. This has potential application in large-scale systematic surveys for which living material may be difficult to obtain.

Photosynthetic Pathway-Related Ultrastructure of C3, C4 and C3-Like C3-C4 Intermediate Sedges (Cyperaceae), With Special Reference to Eleocharis

1995 ◽  
Vol 22 (4) ◽  
pp. 521 ◽  
Author(s):  
JJ Bruhl ◽  
S Perry
Keyword(s):  
Carbon Assimilation ◽  
Mestome Sheath ◽  
Carbon Reduction ◽  
Peripheral Reticulum ◽  
Δ13c Value ◽  
Bundle Sheath Cells ◽  
Photosynthetic Carbon ◽  
Ultrastructural Characteristics ◽  
Photosynthetic Carbon Assimilation ◽  
Photosynthetic Carbon Reduction

The ultrastructure of photosynthetic organs (leaf blades and culms) was investigated in eight species from four genera of sedges: Fimbristylis (C, fimbristyloid anatomy), Pycreus (C4 chlorocyperoid anatomy), Rhynchospora (C4 rhynchosporoid anatomy) - all NADP-ME (malic enzyme) type, and uninvestigated C3, C4 (eleocharoid anatomy, NAD-ME type) and C3-like C3-C4 intermediate species of Eleocharis. Ultrastructural characteristics previously reported for the former anatomical types are largely confirmed, though some evidence of poorly developed peripheral reticulum in C4 rhynchosporoid sedges is presented. Sedges, regardless of anatomical and biochemical type, possess a suberised lamella in photosynthetic organs which is invariably present in and confined to the mestome sheath cell walls, though it is often incomplete in the radial walls. By contrast with other C4 sedges, NAD-ME Eleocharis species and the C3-like C3-C4 intermediate E. pusilla possess abundant mitochondria and chloroplasts with well-stacked grana in the photosynthetic carbon reduction (PCR) (Kranz)/bundle sheath cells. Peripheral reticulum is well developed in NAD-ME species in both PCR and photosynthetic carbon assimilation (PCA) (C4 mesophyll) chloroplasts, but differs from that seen in chlorocyperoid and fimbristyloid type sedges. The suberised lamella and starch grains (well preserved), and granal stacks (poorly preserved) are identifiable in dried herbarium material (Eleocharis). Prediction of C4 biochemical type of sedges should be possible by combining anatomical, ultrastructural and δ13C value data. The significance of the ultrastructural similarities between the C4 NAD-ME and C3-C4 intermediate Eleocharis species is discussed.

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