C-4 grasses

Teeri, J. A., and L. G. Stowe. 1976. "Climatic patterns and the distribution of C-4 grasses in North America." Oecologia... 

Pagani M., Freeman K. H., and Arthur M. A. (1999b) Late Miocene atmospheric CO2 concentrations and the expansion of C-4 grasses. Science 285, 876-879. 

To date, several plant food-derived profilins have been characterized, most of them being evidently involved in PFS. Hazelnut profilin Cor a 2 and the profilins from Rosaceae fruits strawberry Fra a 4, apple Mai d 4, cherry Pru av 4, almond Pru du 4, peach Pru p 4, and pear Pyr c 4, for example, are considered to cross-react with grass and/or birch pollen Bet v 2 profilin (van Ree et al. 1995). Reactions to celery Api g 4 and carrot Dau c 4 are observed in patients with concomitant birch- or mugwort pollen allergy (celery-mugwort-spice syndrome) (Egger et al. 2006). The... 

The C4 (dicarboxylic acid) pathway of photosynthetic carbon assimilation may be seen as a biochemical elaboration of the RPP cycle. In this pathway CO2 is transferred via the C-4 carboxyl of C4 acids to the reactions of the RPP cycle. Discovered in sugar cane, the pathway was first thought to be peculiar to tropical grasses but was later found in species of dicotyledons, Amaranthus (Amaranthaceae), and Atriplex (Chenopodiaceae). 

A small additional contribution may be expected in form of dry grass, roadside and spoiled hay, which is unsuited as animal food. A small contribution from 3% of the grassland area results in 0.12 Gt/y C (3% from 4.2 Gt C total grass up-growth per year) or 1% of our present primary energy consun tion. 

CH3CH2CH = CH>CH2CH2OH, C6H120, Mr 100.16, bpm3 156-157 °C, 4° 0.8459, nj) 1.4384, is a colorless liquid with the characteristic odor of freshly cut grass. Robinia pseudacacia and mulberry leaf oil contain up to 50% leaf alcohol, and green tea up to 30%. Small quantities occur in the green parts of nearly all plants. 

Apart from saturated fatty acids, Simoneit and Mazurek (1982) observed low concentrations of unsaturated fatty acids (range C,4-Ci7) a-hydroxy fatty acids (range C 0-C24) that are known components of grass wax dicarboxylic acids (range C 0-C24) that probably arise from the direct biodegradation of hydroxy fatty acids and diterpenoidal acids occurring as diagenetic products of diterpenoids from coniferous resins. 

On the other hand, the Hatch-Slack photosynthetic cycle is important for tropical grasses, com and sugarcane. Phosphenol-pyr-uvate carboxylase is responsible for the primary carboxylation reaction. The first stable carbon compound is a C-4 acid, which is subsequently decarboxylated (101,102). The fundamentals and sys-tematics of the non-statistical distributions of isotopes in natural compounds have been reviewed (103). 

Chamaecynane type (223) was first encountered with the characterization of C]4 sesquiterpenes - e.g., dehydrochamaecynenol (232) from Chamaecyparis formosensis (14). Some half dozen compounds with this stereochemistry are known at present and all of these are C14 compounds isolated from C formosensis. The other cis fused type, 224, was uncovered with the structure elucidation of (+)-occidentalol (233), isolated from the heartwood of Thuja occidentalis (368). The aromatic compound occidol (234) co-occurs with occidentalol in the Thuja wood. Several compounds of intermedeane type (225) are known at present and some of these have been isolated from woody tissues. Intermedeol (235) itself was first isolated from the Indian race of the grass Bothriochloa intermedia (95). (-)-Callitrisin (236) is a constituent of Callitris columellaris heartwood (59, 158). 

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