On the utilization of carbon in fertilizers through rice roots under pot experimental condition

Uptake of carbon and nitrogen through roots of rice and corn plants, grown in soils treated with13C and15N dual-labeled cattle manure compost

“…They also showed that the carbon applied as sodium hydrogen carbonate was located in the upper leaf sheaths (40.8% of C absorbed), but that the carbon applied as urea was located in the roots (42.3%). Similarly, other experiments with 14C-labeled green manure showed that 14C located in the roots (Mitsui and Kurihara 1962b). Apparently these results indicate that the form of the carbon source, namely organic or inorganic, markedly affected the carbon location in rice plants, in terms of carbon absorption, translocation, metabolism, or assimilation.…”

Further evidence for gaseous CO2transport in relation to root uptake of CO2in rice plant

“…2, air was injected into the medullary cavity and the leakage of the air through the leaf sheath was monitored by the appearance of air bubbles. 2 fixation between rice and wheat CO 2 fixation includes both dark CO 2 fixation in the roots and CO 2 fixed by photosynthesis after being transported to the shoots in the inorganic state. Therefore, CO 2 fixed in the roots represents the total amount of both dark fixation of CO 2 in the roots and organic carbon transported from the shoots to the roots.…”

“…Numerous studies have demonstrated that plants are capable of absorbing CO 2 through the roots (1)(2)(3)(4). Some of these studies showed that the amount of CO 2 absorbed by the roots does not exceed 1 % of that assimilated by the leaves, and it was eventually concluded that root uptake of CO 2 is of no importance from the view point of crop production.…”

Internal transport of CO2 from the root‐zone to plant shoot is pH dependent

“…There have been a number of attempts to evaluate the impact of CO 2 enrichment in the root‐zone (e.g. Mitsui and Kurihara , Lee and Woolhouse , Vapaavuori and Pelkonen , Kimball et al , Vuorinen et al , Cramer et al , Cramer and Richards , Wanek and Popp , Nikolic and Romheld , He et al ), but no study has quantified the pathway of CO 2 movement and its fate over a short time scale of minutes to an hour. Our results suggest that the pH of the solution surrounding the roots influences both CO 2 uptake and where the CO 2 travels within the plant.…”

“…Elevated root‐zone CO 2 generally enhances plant growth (Enoch and Olesen ). The magnitude of the enhancement varied from 0.2 to over 100%, depending on the concentration of CO 2 supplied (0.5–13 mM solution or up to 50 000 ppm air in the root‐zone), the length of time CO 2 was supplied and the plant species such as cotton (Kimball et al ), tomato (Cramer and Richards ), barley (Cramer et al ), lettuce (He et al ), rice (Mitsui and Kurihara ), willow (Vapaavuori and Pelkonen , Vuorinen et al , ), Populus and Sambucus (Wanek and Popp ), and Pinus taeda (Ford et al ). In some cases, root‐zone CO 2 elevated by bicarbonate solutions with high pH has a negative impact on growth through excessive accumulation of organic acid (e.g.…”