Gas transport through rice

Lee, K.K.; Holst, RW; Watanabe, Iwao; App, A. A.

doi:10.1080/00380768.1981.10431266

Cited by 46 publications

(19 citation statements)

References 22 publications

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“…However, Seiler et al (22) reported that stomatal closing by exposure to darkness or increased CO2 in the atmosphere did not significantly affect the methane emission rate from rice plants. Similar results have been observed using exogenously applied ethylene (18) and CO2 (12) passed through the rice plants from the roots to the shoots. These observations indicate that the stomata are not the major release site of methane or other gases from rice plants.…”

supporting

confidence: 74%

Mechanism of Methane Transport from the Rhizosphere to the Atmosphere through Rice Plants

Nouchi¹,

Mariko²,

Aoki³

1990

Plant Physiol.

349

174

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To clarify the mechanisms of methane transport from the rhizosphere into the atmosphere through rice plants (Oryza sativa L.), the methane emission rate was measured from a shoot whose roots had been kept in a culture solution with a high methane concentration or exposed to methane gas in the gas phase by using a cylindrical chamber. No clear correlation was observed between change in the transpiration rate and that in the methane emission rate. Methane was mostly released from the culm, which is an aggregation of leaf sheaths, but not from the leaf blade. Micropores which are different from stomata were newly found at the abaxial epidermis of the leaf sheath by scanning electron microscopy. The measured methane emission rate was much higher than the calculated methane emission rate that would result from transpiration and the methane concentration in the culture solution. Rice roots could absorb methane gas in the gas phase without water uptake. These results suggest that methane dissolved in the soil water surrounding the roots diffuses into the cell-wall water of the root cells, gasifies in the root cortex, and then is mostly released through the micropores in the leaf sheaths.Recent studies of ancient air trapped in polar ice cores (7,17) have shown that the concentration of atmospheric methane has more than doubled during the past 200 years and that during the last decade atmospheric methane has increased approximately 1% per year (4). Because methane is one of the so-called greenhouse gases, in addition to C02, N20, 03, and chlorofluorocarbons, the increase in atmospheric methane may cause an increase in the globally averaged surface temperature (19,25). About 80% of methane emissions are produced biologically by methanogenic bacteria in flooded soils and in the intestines ofdomestic animals (9). Rice (Oryza sativa L.) paddy fields are known to be a major source of methane (5) and the area of rice paddy fields in the world averaged over the last 35 years has increased 1.6% per year (13). Although a full explanation of increasing atmospheric methane concentration remains uncertain, the increasing area of rice paddy fields in the world is considered to be an important cause of the recent shifts in the atmospheric methane balance. Studies have found that methane emission from vegetated plots in rice paddy fields were much higher than from unvegetated plots (6, 14). Therefore, Cicerone and Shetter (6) proposed that methane emitted to the atmosphere from rice paddy fields is transported mostly through rice plants and not across the water-air interface via bubbles or molecular diffusion.In rice and other hydrophytes, it is well known that atmospheric 02 is transported to the submerged organs from the leaf parts above water through the aerenchyma and intercellular gas space systems by diffusion (2, 10, 15, 24) or by mass flow (8). Since these internal air spaces in rice plants are particularly well developed in the culm (1) and roots (16), the ventilation system in rice plants plays an important role in t...

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supporting

confidence: 74%

Mechanism of Methane Transport from the Rhizosphere to the Atmosphere through Rice Plants

Nouchi¹,

Mariko²,

Aoki³

1990

Plant Physiol.

349

174

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“…Other emission pathways (diffusion through the water colutnn: 2%, ebullition of gas bubbles: 8%) are of minor significance, Labotatory experiments on gas pertneability of the aerenehyma systetns of the two rice cultivars studied demonstrated for the first time that the root-shoot transition zone of the rice plant provides the most important resistance for plant-mediated gas exchange between rice plants and the attnosphere. Previous experiments provided indirect suppott for a resistance to gas transport through rice plants, Ethylene transport frotn the rooting medium via the rice plant to the attnosphere was not proportiotial to the partial pressure of ethylene in the rooting medium (Lee et al 1981), Cutting off the stems of rice plants above the floodwater did not influence CH4 etnission, indicating that the rate-litniting step in plant-mediated CH4 transport was not loeated in the retnoved part of the plants (Denier van der Gon & van Bteemen 1993), However, direet evidence for the loeation of the resistence to gas transport, as obtained in this study, has not been provided in previous experiments.…”

Section: Discussionmentioning

confidence: 99%

Impact of gas transport through rice cultivars on methane emission from rice paddy fields

Butterbach‐Bahl¹,

Papen²,

Rennenberg³

1997

Plant Cell & Environment

245

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Two Italian rice {Oryza sativa var. japonica) cultivars, Lido and Roma, were tested in the field tor methane production, oxidation and emission. In two consecutive years, fields planted with the rice eultivar Lido showed methane emissions l'\-'i\% lower than fields planted with the eultivar Roma. This differenee was observed irrespective of fertilizer treatment. In eontrast to methane emissions, differenees in methane production or oxidation 'were not observed between fields planted with the two eultivars. Plant-mediated transport of methane from the sediment to the atmosphere was the dominating pathway of methane emission. During the entire vegetation period, the contribution of this pathway to total methane emission amounted to c. 90%, whereas the eontribution of gas bubble release and of diffusion through the water eolunin to total methane emission 'was of minor significance. Results obtained from transport studies of tracer gas through the aerenehyma system of riee plants demonstrated that the root-shoot transition zone is the main site of resistance to plant-mediated gas exchange between the soil and tbe atmosphere. The eultivar Lido, showing relatively low methane emissions in the field, bad a signifieantly lower gas transport eapaeity through the aerenehyma system than the eultivar Roma. Thus, tbe observed differenees in methane emissions in the field between tbe eultivars Lido and Roma ean be explained by different gas transport eapaeities. Apparently, tbese differenees in gas transport eapaeities are a eonsequenee of differenees in morphology of the aerenebyma systems, espeeially in the root-slioot transition zone. It is, therefore, eoneluded that identifieation and use of high-yielding riee enltivars whieh have a low gas transport eapaeity represent an eeonomieally feasible, environmentally sound and promising approaeb to mitigating methane eniissons from riee paddy fields.

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“…Cultivar differences in methane emission are most likely caused by differences in transport capacity or organic root exudation. Lee et al [1981 ] observed large differences in gas transport capacity among rice varieties, particularly between upland and lowland varieties. ButterbachBahl et al [1997] showed that large differences in methane emissions in two Italian rice varieties were mostly attributed to their differences in transport capacity.…”

Section: Resultsmentioning

confidence: 97%

Relationships between methane production and emission to lacunal methane concentrations in rice

Byrd¹,

Fisher²,

Sass³

2000

Global Biogeochemical Cycles

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Abstract. We measured lacunal methane concentrations in field-grown rice plants as a correlative to both methane production and emissions. Using a gas-tight syringe, 100-pL samples were withdrawn from plant lacunar spaces below the water level and diluted to provide enough volume for analysis by gas chromatography. Lacunal methane concentrations increased throughout the season and, for each sampling date, were usually significantly higher in the cultivars Mars and Cypress (high emitters) when compared with Lemont and Della (low emitters). The field site influenced lacunal methane concentrations, wherein greater lacunal methane concentrations corresponded with greater methane. Methane emission rates were positively correlated with plant lacunal methane concentrations for each cultivar, with an improvement in the relationship during the preheading season. With increases in methane production determined by emissions following field-induced anoxia, lacunal methane concentrations increased accordingly. Lacunal methane concentrations also clearly increased as plant biomass increased, but the relationship depended on field location, which also influenced emissions. Sampling lacunal methane concentrations of rice plants, although labor intensive, is quite flexible, using little field equipment, and may provide an effective alternative to largescale flux measurements in areas not easily accessible.

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Gas transport through rice

Cited by 46 publications

References 22 publications

Mechanism of Methane Transport from the Rhizosphere to the Atmosphere through Rice Plants

Mechanism of Methane Transport from the Rhizosphere to the Atmosphere through Rice Plants

Impact of gas transport through rice cultivars on methane emission from rice paddy fields

Relationships between methane production and emission to lacunal methane concentrations in rice

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