Metabolism of Inorganic Carbon Taken Up by Roots inSalixPlants

Phosphorus Stress-Induced Proteoid Roots Show Altered Metabolism in Lupinus albus

“…In general, C 0 2 uptake for assimilation in root systems is considered negligible (Farmer and Adams, 1991). However, fixation of carbon in roots may be of great importance for carbon balance in roots (Vuorinen et al, 1992) and may result in increased biomass production (Vapaavuori and Pelkonen, 1985). Significant amounts of C 0 2 fixed by tomato (Lycopersicon esculentum L.) roots was transported to the stem and leaves (Bialzyk and Lechowski, 1992).…”

Possible source of ancient carbon in phytolith concentrates from harvested grasses

“…Several studies on inorganic C uptake by terrestrial plants have been carried out since the early 1950s (Vuorinen et al, 1992). Although researchers seem to agree that soildissolved inorganic carbon (DIC) accounted for <3 % of total leaf-fixed CO 2 (Ford et al, 2007;Ubierna et al, 2009), its distribution among above-and below-ground tissue pools can be asymmetrical (for example, 65 % of labeled 13 C was found in the Pinus stem against 35 % in its needles; Ford et al, 2007).…”

The influence of enriched rhizosphere CO2 on N uptake and metabolism in wild‐type and NR‐deficient barley plants

“…Thus NOJ and NHI uptakes are influenced by the CO, component of DIC independently of anaplerotic carbon provision for amino acid synthesis, and CO, may directly affect the uptake of NO; and NHJ in ways unrelated to the NR activity in the tissue. Introduction ^^ j-p^ j ^^5^ Assitnilation of dissolved inorgatiic car-Research on the effect of elevated atmospheric CO2 on bon (DIC = CO2 -1-HCO3) irt the tiutrient solution by plant growth and physiology bas been focused on the ef-plant roots in the dark has been widely observed (Vapaafects of elevated attrtospberic CO2 on the production and vuori and Pelkonen 1985, Vuorinen et al, 1992, Cramer utilization of photosynthate (Taylor et al, 1994, Ele-and Lewis 1993, Cramer et al, 1993, but the signiftvated atmospheric CO2 itihibits shoot respiration (Bunce cance of this process is controversial. The influence of 1994, Thomas and Griffin 1994, WuUschleger et al, enriched CO2 on plant grovsfth was reviewed by Enoch 1994, Ziska and Bunce 1994), while high CO2 in the soil and Olesen (1993), As a consequence of the small coninhibits root respiration (Qi et al, 1994), The effect of el-tribution to the overall carbon btidget of the plant made evated CO2 on apparent respiration may, at least par-by CO2 uptake by roots, they concluded that CO2 prima-…”

“…rily acts as a plant hormone in promoting growth. However, the itifluence of root DIC uptake and assimilation on plant growth may be greater than the contribution of Die to the carbon budget of the plant because of changes in the carbon partitioning (Vuorinen et al, 1992), Changes in partitioning resulting in alteration of the leaf weight ratio (leaf dry weight per tmit plant dry weight) or the specific leaf area (leaf area per unit leaf weight) are likely to be important in determining the growth rate (Poorter and Rettikes 1990),…”

“…The growth of salinity-stressed tomato plants responds positively to ettrichment of the rhizosphere with CO2 (Cramer and Lips 1995), These plants showed higher rates of NOJ uptake than equivalent plants grown with ambient CO2, In contrast, no significant change in NOi uptake was observed in non-salinised plants treated with varying concentrations of CO2, In labelling experiments with H'''COJ supplied to salinised plants, the prodttcts of dissolved inorganic "C incorporation were preferentially diverted into amino acid synthesis and readily transported to the shoot; whereas non-salinised plants accumulated label in organic acids. It was concluded that enriched CO2 can increase the supply of N and anaplerotic carbon for NHJ assimilation and for amino acid synthesis iti roots of plants, which are forced by salirtity to reduce NO3 in the root, incorporation of DIC into organic products in the roots occurs through the activity of PEPc (Amozis et al, 1988, Vuorinen et al, 1992, Cramer et al, 1993, In the leaves of C4 plants, HCOi incorporated by PEPc is derived from the hydration of CO2 by carbonic anhydrase (Edwards and Walker 1983), Labelling studies show that exogenous DIC is readily utilised by PEPc in roots (Vuorinen et al, 1992, Cramer andLewis 1993), and reassimilation of respiratory CO2 is also iikely to occur. Exogenous DIC may enter the root as either CO2 or HCOJ, It seems likely, however, that CO2 would diffuse across the plasmaletnma more readily than HCO3, the entry of which is likely to be thermodynatnically active (Lucas 1983), Nitrate uptake in barley plants grown in NO; is biphasic with a high affinity saturable system at low concentrations (<1 tnM), and a low affinity non-saturable system at higher concentrations , Uninduced plants show a similar response, but the transition to the non-saturable system occurs at lower concentrations.…”