CARBON GAIN IN COFFEA ARABICA DURING CLEAR AND CLOUDY DAYS IN THE WET SEASON

2006 ◽  
Vol 42 (2) ◽  
pp. 147-164 ◽  
Author(s):  
J. C. RONQUIM ◽  
C. H. B. A. PRADO ◽  
P. NOVAES ◽  
J. I. FAHL ◽  
C. C. RONQUIM
Keyword(s):  
Gas Exchange ◽  
Coffea Arabica ◽  
Leaf Gas Exchange ◽  
Photochemical Efficiency ◽  
Vapour Pressure Deficit ◽  
Net Photosynthesis ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Carbon Gain ◽  
Wet Season

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.

GRAFTING FOR IMPROVING NET PHOTOSYNTHESIS OF COFFEA ARABICA IN FIELD IN SOUTHEAST OF BRAZIL

2011 ◽  
Vol 47 (1) ◽  
pp. 53-68 ◽  
Author(s):  
PAULA NOVAES ◽  
JOÃO PAULO SOUZA ◽  
CARLOS HENRIQUE BRITTO ASSIS PRADO
Keyword(s):  
Carbon Balance ◽  
Coffea Arabica ◽  
Leaf Gas Exchange ◽  
Vapour Pressure Deficit ◽  
Net Photosynthesis ◽  
Future Climate ◽  
Future Climate Change ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Midday Depression

SUMMARYLeaf gas exchange and leaf water potential (Ψleaf) were measured seasonally on non-grafted and grafted Coffea arabica on Coffea canephora in the field to investigate whether grafting would be able to protect the carbon balance against the rise of in vapour pressure deficit (VPD) and air temperature (Tair) under future climate change. The net maximum photosynthetic rate obtained from the net photosynthesis (PN) curve as a function of photosynthetic photon flux density (PPFD) in wet and dry periods was used to estimate the integrated potential diurnal net CO2 assimilation (IPPN) around midday. The difference between IPPN and the integrated values of PN during diurnal courses (IPN) was measured to test grafting as suitable practice for minimizing midday depression of PN. Higher values of PN in grafted plants around midday showed that grafting was important even when environmental conditions were favourable in field conditions. Reduced susceptibility of grafted plants to midday depression was revealed by lower values of Ψleaf associated with higher values of PN and leaf transpiration (E) on sunny days in summer and spring, and by higher values of stomatal conductance (gs) around midday in autumn, winter and spring. The differences of E, gs, PN and Ψleaf between non-grafted and grafted plants were higher in dry periods in winter and spring. In addition, the ratio IPN/IPPN in grafted was double that in non-grafted plants around midday in sunny summer and in spring. Indeed, PN and gs of non-grafted plants showed higher dependence on VPD than grafted ones. The lower susceptibility of grafted plants to water stress demonstrated the graft efficiency for increasing positive components of leaf carbon balance of C. arabica in the field, especially under high VPD in projected future climate conditions.

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

Plants ◽  
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.

scholarly journals Autonomy and network modulation of photosynthesis and water relations of Coffea arabica in the field

2008 ◽  
Vol 20 (2) ◽  
pp. 141-151 ◽  
Author(s):  
Lívia H.G. de Camargo-Bortolin ◽  
Carlos H.B. A. Prado ◽  
Gustavo M. Souza ◽  
Paula Novaes
Keyword(s):  
Coffea Arabica ◽  
Vapor Pressure Deficit ◽  
Leaf Gas Exchange ◽  
Principal Component ◽  
Net Photosynthesis ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Physiological Variables ◽  
Physiological Variability

The degree of connection between leaf gas exchange and leaf water potential, and the autonomy of these variables in relation to meteorological conditions were determined in three cultivars of Coffea arabica during clear and cloudy days. High values of vapor pressure deficit, air temperature and photosynthetic photon flux density resulted in low leaf autonomy during a clear day, irrespective the degree of connection among leaf physiological variables. Tight synchronization between physiological and meteorological variables was considered one important cause of net photosynthesis (P N) decreasing during a clear day. In contrast, diurnal P N was around three times higher on a cloudy day, when all cultivars presented high autonomy. Principal component analyses corroborated autonomy results revealing unambiguous opposition between leaf physiological and meteorological vectors, besides less leaf physiological variability throughout the clear day. Despite these general responses during clear and cloudy days, there were significant differences among studied cultivars. Leaf autonomy was an important reference to evaluate C. arabica under environmental stress and should be taken into account when selecting cultivars under field conditions.

scholarly journals Photosynthetic traits of five neotropical rainforest tree species: interactions between light response curves and leaf-to-air vapour pressure deficit

2005 ◽  
Vol 48 (5) ◽  
pp. 815-824 ◽  
Author(s):  
Marcelo Schramm Mielke ◽  
Alex-Alan Furtado de Almeida ◽  
Fábio Pinto Gomes
Keyword(s):  
Gas Exchange ◽  
Mathematical Models ◽  
Tree Species ◽  
Vapour Pressure ◽  
Leaf Gas Exchange ◽  
Vapour Pressure Deficit ◽  
Light Response ◽  
Photon Flux ◽  
Neotropical Rainforest ◽  
Photosynthetic Traits

Measurements of leaf gas exchange at different photosynthetic photon flux density (PPFD) levels were conducted in order to compare the photosynthetic traits of five neotropical rainforest tree species, with a special emphasis on empirical mathematical models to estimate the light response curve parameters incorporating the effects of leaf-to-air vapour pressure deficit (D) on the saturated photosynthetic rate (Amax). All empirical mathematical models seemed to provide a good estimation of the light response parameters. Comparisons of the leaf photosynthetic traits between different species needed to select an appropriate model and indicated the microenvironmental conditions when the data were collected. When the vapour pressure deficit inside the chamber was not controlled, the incorporation of linear or exponencial functions that explained the effects of D on leaf gas exchange, was a very good method to enhance the performance of the models.

scholarly journals CO2 assimilation, photosynthetic light response curves, and water relations of 'Pêra' sweet orange plants infected with Xylella fastidiosa

2003 ◽  
Vol 15 (2) ◽  
pp. 79-87 ◽  
Author(s):  
Gustavo Habermann ◽  
Eduardo Caruso Machado ◽  
João Domingos Rodrigues ◽  
Camilo Lázaro Medina
Keyword(s):  
Sweet Orange ◽  
Leaf Gas Exchange ◽  
Xylella Fastidiosa ◽  
Net Photosynthesis ◽  
Co2 Concentration ◽  
Relative Effect ◽  
Carboxylation Efficiency ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Response Curves

Plants with citrus variegated chlorosis (CVC), a disease caused by the xylem-limited bacteria Xylella fastidiosa, have leaves with water deficiency symptoms and are associated with decreases on the net photosynthesis and transpiration rates. Using healthy and CVC-affected 'Pêra' sweet orange plants on 'Rangpur' lime rootstock, the leaf gas exchange variables were measured with an open-gas portable photosynthesis system. All plants were watered and the leaf water potential (Yw) was measured by isopiestic thermocouple psychrometric technique. The net photosynthesis (A) vs. internal leaf CO2 concentration (A/Ci curves) was analyzed. The relative effect of stomatal resistance on photosynthesis (S%) and the estimation of carboxylation efficiency were calculated. The rates of photosynthesis and transpiration, stomatal conductance, and internal leaf CO2 concentration (Ci) were also measured while varying the photosynthetic photon flux density (PPFD). The S% values were approximately 30 % greater in infected plants when compared to healthy ones. The light compensation point for diseased plants was higher than in the healthy ones, and the saturation light point in plants with CVC was twofold lower. The lower Yw in diseased plants favours the hypothesis of xylem occlusion, which probably caused a lower water supply to the mesophyll, thus decreasing the photosynthesis and transpiration rates. Nevertheless, there was also a reduction in the photosynthetic metabolic activities, represented by lower carboxylation efficiency and photochemical disturbances that were detected in diseased plants.

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

1980 ◽  
Vol 10 (3) ◽  
pp. 429-435 ◽  
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.

Seasonal variation of carbon assimilation in mango (cv. Kensington Pride): effect of flowering treatments

2003 ◽  
Vol 54 (3) ◽  
pp. 309 ◽  
Author(s):  
Alonso González ◽  
S. J. Blaikie
Keyword(s):  
Gas Exchange ◽  
Chlorophyll Content ◽  
Leaf Gas Exchange ◽  
Average Rate ◽  
Carbon Assimilation ◽  
Vapour Pressure Deficit ◽  
Dry Season ◽  
Fruit Yield ◽  
Wet Season ◽  
The Tropics

In the tropics of northern Australia the mango cultivar Kensington Pride exhibits erratic flowering and fruiting and low productivity. Two treatments to manipulate flowering were applied. The first, mango flowering treatment (MFT), involved cutting a cincture through the bark around the circumference of the tree trunk and tying into the cincture a length of twine soaked in a solution of morphactin, CF125. The second involved applying paclobutrazol (PBZ) as a soil drench around the trunk of the tree. Phenology, leaf gas exchange, and fruit yield were assessed over 2 seasons in 3 separate groups of trees in commercial orchards near Darwin.Both MFT and PBZ supported earlier and/or more intense flowering in the season of application than did control trees. The PBZ was re-applied annually and the beneficial effect on flowering occurred in successive years. The MFT was applied once only at the start of the experiment and the effect of MFT was not evident in the second season.The effect of MFT on gas exchange was characterised by a severe reduction in net carbon assimilation (Amax), stomatal conductance (gs), and transpiration (E) for up to 4 months following treatment. Trees receiving PBZ generally had higher rates of leaf gas exchange than MFT trees but similar to control trees. During the dry season, leaves of MFT, control, and PBZ trees had similar rates of Amax. In the year of application, chlorophyll content of MFT trees was lower than that of the other treatments, but in the second year it was very similar to control trees. PBZ trees had the highest chlorophyll content during the study. Commercial fruit yield of PBZ-treated trees was 2–3 times higher than that of control or MFT trees. Independent of the flowering treatments, Amax followed a seasonal trend with an average rate of 9.05 μmol/m2.s (min. 4.42, max. 13.2) during the wet season (January–April), and 4.2 μmol/m2.s (min. 1.11, max. 8.7) during the dry season (May–October). Regression analysis demonstrated that 82% of the variation in gs and 76% of the variation in Amax could be explained by the effect of vapour pressure deficit of the leaf (VPDL) in field-grown mango trees.

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

1993 ◽  
Vol 118 (3) ◽  
pp. 366-370 ◽  
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.

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

1995 ◽  
Vol 22 (6) ◽  
pp. 1015 ◽  
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.

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