scholarly journals Relation between Mesophyll Surface Area, Photosynthetic Rate, and Illumination Level during Development for Leaves of Plectranthus parviflorus Henckel

1975 ◽  
Vol 55 (6) ◽  
pp. 1067-1070 ◽  
Author(s):  
Park S. Nobel ◽  
Lawrence J. Zaragoza ◽  
William K. Smith
Keyword(s):  
Surface Area ◽  
Photosynthetic Rate ◽  
Illumination Level ◽  
Mesophyll Surface Area

scholarly journals Maximum CO 2 diffusion inside leaves is limited by the scaling of cell size and genome size

2021 ◽  
Vol 288 (1945) ◽  
pp. 20203145
Author(s):  
Guillaume Théroux-Rancourt ◽  
Adam B. Roddy ◽  
J. Mason Earles ◽  
Matthew E. Gilbert ◽  
Maciej A. Zwieniecki ◽  
...  
Keyword(s):  
Genome Size ◽  
Surface Area ◽  
Three Dimensional ◽  
Mesophyll Cells ◽  
Spongy Mesophyll ◽  
Phase Diffusion ◽  
Leaf Mesophyll ◽  
Leaf Tissues ◽  
Mesophyll Surface Area ◽  
Leaf Volume

Maintaining high rates of photosynthesis in leaves requires efficient movement of CO 2 from the atmosphere to the mesophyll cells inside the leaf where CO 2 is converted into sugar. CO 2 diffusion inside the leaf depends directly on the structure of the mesophyll cells and their surrounding airspace, which have been difficult to characterize because of their inherently three-dimensional organization. Yet faster CO 2 diffusion inside the leaf was probably critical in elevating rates of photosynthesis that occurred among angiosperm lineages. Here we characterize the three-dimensional surface area of the leaf mesophyll across vascular plants. We show that genome size determines the sizes and packing densities of cells in all leaf tissues and that smaller cells enable more mesophyll surface area to be packed into the leaf volume, facilitating higher CO 2 diffusion. Measurements and modelling revealed that the spongy mesophyll layer better facilitates gaseous phase diffusion while the palisade mesophyll layer better facilitates liquid-phase diffusion. Our results demonstrate that genome downsizing among the angiosperms was critical to restructuring the entire pathway of CO 2 diffusion into and through the leaf, maintaining high rates of CO 2 supply to the leaf mesophyll despite declining atmospheric CO 2 levels during the Cretaceous.

scholarly journals Maximum CO2 diffusion inside leaves is limited by the scaling of cell size and genome size

2020 ◽  
Author(s):  
Guillaume Théroux-Rancourt ◽  
Adam B. Roddy ◽  
J. Mason Earles ◽  
Matthew E. Gilbert ◽  
Maciej A. Zwieniecki ◽  
...  
Keyword(s):  
Genome Size ◽  
Surface Area ◽  
Cell Size ◽  
Vascular Plants ◽  
Leaf Surface ◽  
Leaf Traits ◽  
Mesophyll Cells ◽  
Co2 Diffusion ◽  
Leaf Mesophyll ◽  
Mesophyll Surface Area

SummaryMaintaining high rates of photosynthesis in leaves requires efficient movement of CO2 from the atmosphere to the chloroplasts inside the leaf where it is converted into sugar. Throughout the evolution of vascular plants, CO2 diffusion across the leaf surface was maximized by reducing the sizes of the guard cells that form stomatal pores in the leaf epidermis1,2. Once inside the leaf, CO2 must diffuse through the intercellular airspace and into the mesophyll cells where photosynthesis occurs3,4. However, the diffusive interface defined by the mesophyll cells and the airspace and its coordinated evolution with other leaf traits are not well described5. Here we show that among vascular plants variation in the total amount of mesophyll surface area per unit mesophyll volume is driven primarily by cell size, the lower limit of which is defined by genome size. The higher surface area enabled by smaller cells allows for more efficient CO2 diffusion into photosynthetic mesophyll cells. Our results demonstrate that genome downsizing among the flowering plants6 was critical to restructuring the entire pathway of CO2 diffusion, facilitating high rates of CO2 supply to the leaf mesophyll cells despite declining atmospheric CO2 levels during the Cretaceous.

scholarly journals The bias of a two-dimensional view: comparing two-dimensional and three-dimensional mesophyll surface area estimates using noninvasive imaging

2017 ◽  
Vol 215 (4) ◽  
pp. 1609-1622 ◽  
Author(s):  
Guillaume Théroux-Rancourt ◽  
J. Mason Earles ◽  
Matthew E. Gilbert ◽  
Maciej A. Zwieniecki ◽  
C. Kevin Boyce ◽  
...  
Keyword(s):  
Surface Area ◽  
Noninvasive Imaging ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Mesophyll Surface Area

scholarly journals Photosynthesis and Shoot Health of Five Birch and Four Alder Taxa After Drought and Flooding

2002 ◽  
Vol 20 (1) ◽  
pp. 36-40
Author(s):  
William R. Graves ◽  
Mark A. Kroggel ◽  
Mark P. Widrlechner
Keyword(s):  
Surface Area ◽  
Photosynthetic Rate ◽  
Leaf Surface ◽  
Root Zone ◽  
Subjective Health ◽  
The Other ◽  
Flood Resistance ◽  
Leaf Surface Area ◽  
Managed Landscapes ◽  
Selection Of

Abstract Selection of under-used taxa of birches (Betula L.) and alders (Alnus Miller) for use in managed landscapes can be guided by information on their responses to moisture extremes in the root zone. Our objective was to compare the photosynthesis, leaf surface area, and subjective health ratings of eight relatively obscure birches and alders when treated with drought and flooding in a greenhouse. We also treated ‘Whitespire Sr.’ birch (Betula populifolia) to demonstrate responses of a cultivar common in the nursery trade. Plants used as controls were irrigated daily, whereas pots of flooded plants were immersed. All water was withheld from the drought-treated taxon that showed the least evapotranspiration each day, while amounts of water less than that lost to evapotranspiration each day were added to plants of the other taxa subjected to drought. After three cycles of drought that induced wilting and a reduction in photosynthetic rate, leaf surface area of A. hirsuta had decreased the least, 12%, among the alders. While drought reduced the photosynthesis of all birches during the study, mean photosynthetic rate of drought-treated B. uber was higher than that of B. albosinensis and B. davurica subjected to drought. Flooding for 7 days did not influence photosynthetic rate of any alder but reduced photosynthesis of all the birches except B. davurica. After 21 days of flooding, only plants of B. albosinensis and B. costata were killed, and A. maritima was the only alder that fully sustained photosynthesis. While our data support the idea that most alders and birches are adapted to wet and well-drained sites, respectively, responses to drought varied among the four alders, and the four uncommon birches we grew responded differently to flooding. Specifically, additional evaluations under field conditions should be done to confirm the resilience of A. hirsuta and A. maritima to recurrent drought and to verify whether the comparatively promising (B. davurica and B. uber) and poor (B. albosinensis and B. costata) flood resistance we observed among the birches is meaningful in the landscape.

Mesophyll surface area as measured by physical adsorption of nitrogen: the case of wheat

2000 ◽  
Vol 28 (1-2) ◽  
pp. 139-145 ◽  
Author(s):  
Roberto R. Filgueira ◽  
Silvina I. Golik ◽  
Guillermo O. Sarli ◽  
Jaime R. Jatimliansky ◽  
Santiago J. Sarandón
Keyword(s):  
Surface Area ◽  
Physical Adsorption ◽  
Adsorption Of Nitrogen ◽  
Mesophyll Surface Area

One Million Direct Magnification Microscopy

1971 ◽  
Vol 29 ◽  
pp. 166-167
Author(s):  
J. A. Hugo ◽  
V. A. Phillips
Keyword(s):  
Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Illumination Level ◽  
Level Of Detail ◽  
Photographic Emulsion ◽  
Low Contrast ◽  
Fluorescent Screen ◽  
Resolution Electron ◽  
Lattice Images ◽  
Electron Microscopes

A continuing problem in high resolution electron microscopy is that the level of detail visible to the microscopist while he is taking a picture is inferior to that obtainable by the microscope, readily readable on a photographic emulsion and visible in an enlargement made from the plate. Line resolutions, of 2Å or better are now achievable with top of the line 100kv microscopes. Taking the resolution of the human eye as 0.2mm, this indicates a need for a direct viewing magnification of at least one million. However, 0.2mm refers to optimum viewing conditions in daylight or the equivalent, and certainly does not apply to a (colored) image of low contrast and illumination level viewed on a fluorescent screen through a glass window by the dark-adapted eye. Experience indicates that an additional factor of 5 to 10 magnification is needed in order to view lattice images with line spacings of 2 to 4Å. Fortunately this is provided by the normal viewing telescope supplied with most electron microscopes.

Preparation and characterisation of vanadium pentoxide supported rhodium catalyst

1988 ◽  
Vol 46 ◽  
pp. 946-947
Author(s):  
A. Legrouri
Keyword(s):  
Aqueous Solution ◽  
Thermal Decomposition ◽  
Physicochemical Properties ◽  
Surface Area ◽  
Vanadium Pentoxide ◽  
High Purity ◽  
Gas Adsorption ◽  
Rhodium Catalyst ◽  
Optical Methods ◽  
Reducible Oxides

The industrial importance of metal catalysts supported on reducible oxides has stimulated considerable interest during the last few years. This presentation reports on the study of the physicochemical properties of metallic rhodium supported on vanadium pentoxide (Rh/V2O5). Electron optical methods, in conjunction with other techniques, were used to characterise the catalyst before its use in the hydrogenolysis of butane; a reaction for which Rh metal is known to be among the most active catalysts.V2O5 powder was prepared by thermal decomposition of high purity ammonium metavanadate in air at 400 °C for 2 hours. Previous studies of the microstructure of this compound, by HREM, SEM and gas adsorption, showed it to be non— porous with a very low surface area of 6m2/g3. The metal loading of the catalyst used was lwt%Rh on V2Q5. It was prepared by wet impregnating the support with an aqueous solution of RhCI3.3H2O.

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