Paraheliotropism in two Phaseolus species: combined effects of photon flux density and pulvinus temperature, and consequences for leaf gas exchange

Three cultivars of Coffea arabica, Catuaí Vermelho IAC 81, Icatu Amarelo IAC 2944 and Obatã IAC 1669–20, were evaluated in relation to leaf gas exchange and potential photochemical efficiency of photosystem II under field conditions on clear and cloudy days in the wet season in southeast Brazil. Independent of levels of irradiance, leaf water potential (υleaf) values were always higher than the minimum required to affect daily net photosynthesis (PN). PN, stomatal conductance (gs), leaf transpiration (E) and the index of photochemical efficiency (Fv/Fm) declined on a clear day in all cultivars. The depression of leaf gas exchange and Fv/Fm (specially around midday) caused a strong decrease (about 70 %) in daily carbon gain on a clear day. Under cloudless conditions, gs and PN were correlated with the air vapour pressure deficit (VPDair), but not with photosynthetic photon flux density (PPFD) values. On a cloudy day, the daily carbon gain was barely limited by PPFD below 800 μmol m−2 s−1, the Fv/Fm values showed a slight decrease around midday, and gs and PN were positively correlated with PPFD but not with VPDair. By contrast, irrespective of the contrasting irradiance conditions during the day, PN and E were correlated with gs.

Download Full-text

Leaf gas exchange processes and related characteristics of seven poplar clones under laboratory conditions

Canadian Journal of Forest Research ◽

10.1139/x80-070 ◽

1980 ◽

Vol 10 (3) ◽

pp. 429-435 ◽

Cited By ~ 7

Author(s):

R. Ceulemans ◽

I. Impens

Keyword(s):

Carbon Dioxide ◽

Gas Exchange ◽

Water Use Efficiency ◽

Water Use ◽

Leaf Gas Exchange ◽

Photon Flux ◽

Photon Flux Density ◽

Apparent Quantum Yield ◽

Uptake Rates ◽

Use Efficiency

Different ecophysiological characteristics of various Populus clones (maximum net CO2 uptake rate, apparent quantum yield, photon flux density compensation point, boundary layer resistance, and stomatal and internal resistances to carbon dioxide and water use efficiency) were studied using a gas exchange method. Most significant differences were found in the water use efficiency ratios, the internal resistances to carbon dioxide and the maximum net CO2 uptake rates. Recently selected interamerican Populustrichocarpa crossings (Populus clones Unal, Beaupré, and Trichobel) showed high water use efficiency, high maximum net CO2 uptake rates, and low internal resistances.

Download Full-text

Red and Blue Netting Alters Leaf Morphological and Physiological Characteristics in Apple Trees

Plants ◽

10.3390/plants10010127 ◽

2021 ◽

Vol 10 (1) ◽

pp. 127

Author(s):

Richard M. Bastías ◽

Pasquale Losciale ◽

Camilla Chieco ◽

Luca Corelli-Grappadelli

Keyword(s):

Gas Exchange ◽

Leaf Gas Exchange ◽

Red Light ◽

Net Photosynthesis ◽

Fruit Trees ◽

Photosynthetic Photon Flux Density ◽

Photon Flux ◽

Photon Flux Density ◽

Apple Trees ◽

Intrinsic Water Use Efficiency

There is little information about the role of red and blue light on leaf morphology and physiology in fruit trees, and more studies have been developed in herbaceous plants grown under controlled light conditions. The objective of this research was to evaluate the effect of red and blue screens on morpho-anatomy and gas exchange in apple leaves grown under ambient sunlight conditions. Apple trees cv. Fuji were covered by 40% red and blue nets, leaving trees with 20% white net as control. Light relations (photosynthetic photon flux density, PPFD; red to far-red light ratio, R/FR and blue to red light ratio, B/R), morpho-anatomical features of the leaf (palisade to spongy mesophyll ratio, P/S, and stomata density, SD) and leaf gas exchange (net photosynthesis rate, An; stomatal conductance, gs; transpiration rate, E; and intrinsic water use efficiency, IWUE) were evaluated. Red and blue nets reduced 27% PPFD, reducing by 20% SD and 25% P/S compared to control, but without negative effects on An and gs. Blue net increased gs 21%, leading to the highest E and lowest IWUE by increment of B/R light proportion. These findings demonstrate the potential use of red and blue nets for differential modulation of apple leaf gas exchange through sunlight management under field conditions.

Download Full-text

Gas Exchange of Four Cassava Cultivars in Relation to Light Intensity

Experimental Agriculture ◽

10.1017/s001447970000079x ◽

1982 ◽

Vol 18 (4) ◽

pp. 375-382 ◽

Cited By ~ 5

Author(s):

Jairo A. Palta

Keyword(s):

Gas Exchange ◽

Light Intensity ◽

Flux Density ◽

Direct Effect ◽

Photosynthetic Rate ◽

Photosynthetic Apparatus ◽

Photon Flux ◽

Photon Flux Density ◽

Light Saturation ◽

Effect Of Light

SUMMARYGas exchange measurements were carried out on four cassava cultivars, M. COL22, M. MEX59, M. COL638, and M. VEN218, under a range of light intensities, to investigate possible differences in photosynthesis and transpiration. Over the range of photon flux density 100–1500 μE m−2 s−1 leaves showed a light saturation response typical of C-3 plants with little increase in photosynthetic rate above 1000–1500 μE m−2 s−1 (200–300 Wm−2 PAR). At light saturation there were significant differences in photosynthetic rates between cultivars, with the highest 10% greater than the lowest. Part of the response could be attributed to increased stomatal aperture, and a greater part to a direct effect of light intensity on the photosynthetic apparatus. Transpiration increased with light intensity levels, but no significant differences were observed between cultivars.

Download Full-text

Water Deficits and Environmental Factors Affect Photosynthesis in Leaves of Cucumber (Cucumis sativus)

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.118.3.366 ◽

1993 ◽

Vol 118 (3) ◽

pp. 366-370 ◽

Cited By ~ 23

Author(s):

Abdul K. Janoudi ◽

Irvin E. Widders ◽

James A. Flore

Keyword(s):

Gas Exchange ◽

Feedback Inhibition ◽

Leaf Gas Exchange ◽

Photon Flux ◽

Photon Flux Density ◽

Carbon Dioxide Assimilation ◽

Exchange System ◽

Ambient Temperatures ◽

Use Efficiency ◽

Gas Exchange System

Cucumber plants were cultured in a greenhouse and subjected to either well-watered or water deficit conditions that reduced leaf water potential to-0.6 MPa. Leaf gas exchange measurements were conducted using an open gas exchange system. Carbon dioxide assimilation (A) attained saturation at a photon flux density (PFD) of 1000 μmol·m-2·s-1 (400-700 nm). There were no significant differences in A at ambient temperatures between 16 and 34C. Water use efficiency decreased rapidly with increasing vapor-pressure deficits to 2.5 kPa. Water stressed plants had lower stomata1 conductances and CO2 assimilation rates. The decrease in A was only partially due to stomata1 closure. The A vs. intercellular CO (Ci) relationship for stressed leaves revealed a change in the CO, compensation point, and that nonstomatal factors were contributing to the decrease in A in stressed plants. Thus, feedback inhibition of A may have occurred through photoassimilate accumulation. The concentrations of sucrose and raffinose were higher, and the concentration of stachyose was lower in leaves of stressed than of well-watered plants.

Download Full-text

Gas Exchange of Field-Grown Pinus radiata - Relationships With Foliar Nutrition and Water Potential, and With Climatic Variables

Functional Plant Biology ◽

10.1071/pp9951015 ◽

1995 ◽

Vol 22 (6) ◽

pp. 1015 ◽

Cited By ~ 5

Author(s):

DW Sheriff

Keyword(s):

Gas Exchange ◽

Water Potential ◽

Flux Density ◽

Pinus Radiata ◽

Vapour Pressure ◽

Vapour Pressure Deficit ◽

Photosynthetic Photon Flux Density ◽

Photon Flux ◽

Photon Flux Density ◽

Photosynthetic Photon Flux

Gas exchange measurements were conducted on Pinus radiata to investigate relationships between these and leaf-air vapour pressure deficit, photosynthetic photon flux density, and foliar temperature, water potential and nutrition in the field. Multiple non-linear regressions indicated strong relationships between gas exchange and foliar [P] (but of no other nutrient), leaf-air vapour pressure deficit, photosynthetic photon flux density, foliar water potential and temperature. The final regression produced for relationships between gas exchange and these variables explained 81% of the variance in the data. Micro-climate and foliar data from another site were used to predict gas exchange using the regressions and calculated parameters. Good agreement was obtained between the predicted values and carbon assimilation measured at that site. The relationship was poorer for leaf conductance.

Download Full-text

CO2 assimilation and transpiration balance in species of genus Vitis cultivated in vivo and in vitro. Estimation of stomatal and cuticular transpiration in vitro

OENO One ◽

10.20870/oeno-one.1998.32.2.1054 ◽

1998 ◽

Vol 32 (2) ◽

pp. 91

Author(s):

Francesco Iacono ◽

Lucia Martinelli

Keyword(s):

Relative Humidity ◽

Gas Exchange ◽

Leaf Gas Exchange ◽

Photosynthetic Photon Flux Density ◽

Photon Flux ◽

Photon Flux Density ◽

Cuticular Transpiration ◽

Vitis Riparia

The influence of genotype on leaf gas exchange was investigated for Vitis riparia and Vitis rupestris plants cultured in vivo and in vitro. Gas exchange was measured at constant temperature and photosynthetic photon flux density and at varying relative humidity from 75 p. cent to 65 p. cent.Differences of transpiration and CO2 assimilation rates between genotypes were observed that did not depend upon conditions. Water use efficiency was strongly controlled by the genotype.Linear correlations between assimilation, transpiration and relative humidity were used to estimate extra stomatal (cuticular) and stomatal transpiration of in vitro plants. Cuticular transpiration of in vitro plants was also measured directly during the darkness. Our results confirmed the indirect estimates of cuticular transpiration elaborated with a linear regression model. Results also show that cuticular transpiration of in vitro grown plants may be relevant and is strongly influenced by the genotype. Similarly, the sensitivity of plantlets to transplantation from in vitro to in vivo conditions may be strongly related by the genotype.

Download Full-text