Acquisition and Diffusion of CO2 in Higher Plant Leaves

Evans, John R.; Loreto, Francesco

doi:10.1007/0-306-48137-5_14

Cited by 185 publications

(263 citation statements)

References 112 publications

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“…We therefore suggest this to be an orientation toward CO 2 supply, as has been proposed for the chloroplast orientation around the CO 2 -containing intercellular air spaces in terrestrial plants (Evans and Loreto, 2000). In terrestrial leaves, CO 2 enters through the stomata and then readily diffuses through intercellular airspaces, finally reaching the chloroplast.…”

Section: Chloroplast Orientation As Evidence For Epidermal Diffusion supporting

confidence: 67%

Submergence-Induced Morphological, Anatomical, and Biochemical Responses in a Terrestrial Species Affect Gas Diffusion Resistance and Photosynthetic Performance

Pons²,

et al. 2005

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Gas exchange between the plant and the environment is severely hampered when plants are submerged, leading to oxygen and energy deficits. A straightforward way to reduce these shortages of oxygen and carbohydrates would be continued photosynthesis under water, but this possibility has received only little attention. Here, we combine several techniques to investigate the consequences of anatomical and biochemical responses of the terrestrial species Rumex palustris to submergence for different aspects of photosynthesis under water. The orientation of the chloroplasts in submergence-acclimated leaves was toward the epidermis instead of the intercellular spaces, indicating that underwater CO 2 diffuses through the cuticle and epidermis. Interestingly, both the cuticle thickness and the epidermal cell wall thickness were significantly reduced upon submergence, suggesting a considerable decrease in diffusion resistance. This decrease in diffusion resistance greatly facilitated underwater photosynthesis, as indicated by higher underwater photosynthesis rates in submergence-acclimated leaves at all CO 2 concentrations investigated. The increased availability of internal CO 2 in these ''aquatic'' leaves reduced photorespiration, and furthermore reduced excitation pressure of the electron transport system and, thus, the risk of photodamage. Acclimation to submergence also altered photosynthesis biochemistry as reduced Rubisco contents were observed in aquatic leaves, indicating a lower carboxylation capacity. Electron transport capacity was also reduced in these leaves but not as strongly as the reduction in Rubisco, indicating a substantial increase of the ratio between electron transport and carboxylation capacity upon submergence. This novel finding suggests that this ratio may be less conservative than previously thought.

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Section: Chloroplast Orientation As Evidence For Epidermal Diffusion supporting

confidence: 67%

Submergence-Induced Morphological, Anatomical, and Biochemical Responses in a Terrestrial Species Affect Gas Diffusion Resistance and Photosynthetic Performance

Pons²,

et al. 2005

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“…It seems likely that the gradient or intercellular conductance would limit photosynthesis in leaves which have stomata only on one surface (i.e. hypostomatous leaves) (Parkhurst and Mott, 1990;Evans and Loreto, 2000). We technically altered the amphi-to hypostomatous leaves by attaching the cup on one surface.…”

Section: Effects Of Cup Attachment On Co2 Environment In Leavesmentioning

confidence: 99%

“…The CO2 diffuses from the outside to the intercellular airspace through stomatal pores on the surface of the leaf. From there, it diffuses in the liquid phase to the fixation sites in the mesophyll cells (Evans and Loreto, 2000). Diffusion is a passive physical process, but in plants can be regulated.…”

Section: Introductionmentioning

confidence: 99%

Tracing Photosynthetic Response Curves with Internal CO<sub>2</sub> Measured Directly

Tominaga

Kawamitsu

2015

ecb

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In this study, a system to measure leaf internal CO2 (Ci) was incorporated into an open gas exchange system (LI-COR, Lincoln, NE, USA). The Ci was directly measured with a cup attached to the abaxial surface of sunflower (Helianthus annuus L.) leaves with open stomata while normal CO2 and water vapor exchange through the same section of adaxial surface was simultaneously detected. The potential problems in the system, namely bulk air flow through the leaf, diffusion leaks, and change in the CO2 gradient inside the leaf, were examined with the aim to apply the system to measure net photosynthesis at various Ci (i.e. A Ci curves). A micro blower constantly circulated the air in a loop without pressure pulses or bulk air movement through the leaf. The measured Ci (Ci(m)) generally followed the external CO2 as much as the calculated one (Ci(c)). There was close agreement between the Ci(m) and the Ci(c) particularly at low Ci, and the diffusion leak hardly affected the relationship between the two. Despite possible alterations of leaf properties by cup attachment, the direct measurement is expected to cast a new light on leaf gas exchange.

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“…A value of 0.85 for total leaf absorptance was assumed (Evans and Loreto, 2000), and a factor of 0.5 for the partitioning of light between the two photosystems (Laisk and Loreto, 1996).…”

Section: Gas Exchange Measurementsmentioning

confidence: 99%

Stomatal and non-stomatal limitations on leaf carbon assimilation in beech (Fagus sylvatica L.) seedlings under natural conditions

et al. 2012

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Limitations to diffusion and biochemical factors affecting leaf carbon uptake were analyzed in young beech seedlings (Fagus sylvtica L.) growing in natural gaps of a beech-wood at the southern limit of the species. Half of the seedlings received periodic watering in addition to natural rainfall to reduce the severity of the summer drought. Plant water status was evaluated by measuring predawn water potential. Basic biochemical parameters were inferred from chlorophyll fluorescence and photosynthesis-CO 2 curves (A-C c ) under saturating light. The curves were established on three dates during the summer months. The main variables studied included: stomatal and mesophyll conductance to CO 2 (g s and g m respectively), maximum velocity of carboxylation (V cmax ) and maximum electron transport capacity (J max ). The g m was estimated by two methodologies: the curve-fitting and J constant methosds.Seedlings withstood moderate water stress, as the leaf predawn water potential (Ψ pd ) measured during the study was within the range -0.2 to -0.5 MPa. Mild drought caused g s and g m to decrease only slightly in response to Ψ pd . However both diffusional parameters explained most of the limitations to CO 2 uptake. In addition, it should be highlighted that biochemical limitations, prompted by V cmax and J max , were related mainly to ontogenic factors, without any clear relationship with drought under the moderate water stress experienced by beech seedlings through the study.The results may help to further understanding of the functional mechanisms influencing the carbon fixation capacity of beech seedlings under natural conditions. Key words: diffusion limitations; stomatal conductance; mesophyll conductance; photosynthesis; drought; regeneration. Resumen Limitaciones estomáticas y no-estomáticas en la asimilación foliar de carbono en brinzales de haya (Fagus sylvatica L.) bajo condiciones naturalesLas limitaciones a la difusión de CO 2 y los factores bioquímicos que afectan la captura foliar de carbono fueron analizadas en jóvenes brinzales de haya (Fagus sylvtica L.) que crecían en un claro de un hayedo en el límite Sur de la distribución de la especie. La mitad de los brinzales recibieron periódicamente un riego adicional a la lluvia caída durante el verano con el objeto de minimizar la sequía estival. El grado de estrés hídrico soportado por las plantas fue evaluado a través de la medida del potencial hídrico al pre-alba (Ψ pd ). Los parámetros funcionales básicos que condicionan la fijación de carbono fueron inferidos a través de curvas de respuesta bajo luz saturante en las que se relaciona la tasa neta de fotosíntesis (A), y la concentración de CO 2 en el interior de los cloroplastos (C c ), en conjunción con medidas de fluorescencia de la clorofila. Dichas curvas se elaboraron en tres momentos a lo largo de los meses de verano, infiriéndose de las mismas: las conductancias estomáticas y del mesófilo al CO 2 (g s y g m respectivamente), la velocidad máxima de carboxilación (V cmax ) y la tasa máxima de tr...

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Acquisition and Diffusion of CO2 in Higher Plant Leaves

Cited by 185 publications

References 112 publications

Submergence-Induced Morphological, Anatomical, and Biochemical Responses in a Terrestrial Species Affect Gas Diffusion Resistance and Photosynthetic Performance

Submergence-Induced Morphological, Anatomical, and Biochemical Responses in a Terrestrial Species Affect Gas Diffusion Resistance and Photosynthetic Performance

Tracing Photosynthetic Response Curves with Internal CO<sub>2</sub> Measured Directly

Stomatal and non-stomatal limitations on leaf carbon assimilation in beech (Fagus sylvatica L.) seedlings under natural conditions

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