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

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.

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LEAF GAS EXCHANGE IN TWO DWARF COCONUT GENOTYPES IN THE SOUTHEAST OF BAHIA STATE, BRAZIL.

CORD ◽

10.37833/cord.v18i02.362 ◽

2002 ◽

Vol 18 (02) ◽

pp. 34

Author(s):

Gomes, F.P. ◽

Mielke, M.S. ◽

Almeida, A. F. ◽

Muniz, W. S.

Keyword(s):

Gas Exchange ◽

Water Vapour ◽

Leaf Gas Exchange ◽

Cocos Nucifera ◽

Vapour Pressure Deficit ◽

Light Response ◽

Negative Influence ◽

Water Vapour Pressure ◽

Response Curves ◽

Palm Trees

Net photosynthetic (A) and leaf transpiration (E) rates and stomatal conductance to water vapour (gs) of Malayan Yellow Dwarf (MYD) and Brazilian Green Dwarf (BGD) coconut accessions (Cocos nucifera var. ‘nana’ L.) were studied and discussed in terms of the technical aspects related to light-response curves in field conditions. Measurements of gas exchange were performed during four days, in April and may 2000, at the Cocoa Research Center Experimental Station (Una - BA, Brazil). The A, gs and E parameters were significantly (P < 0.05) different between the two genotypes. The mean maximum values of A, gs and E were 10.4 and 12.0 µmol CO2 m-2 s-1, 0.21 and 0.35 mol H2O m-2 s-1 and 3.07 and 3.69 mmol m-2 s-1 for MYD and BGD, respectively. For both genotypes a good fitting of the light-response curve models were obtained, indicating that A and gs were dependent of the photosynthetically active radiation incident on leaf surface (Qi), in spite of high genotipic variation. Interesting results were achieved when an empirical multiplicative model was used. The model relating A or gs with Qi and with leaf-to-air water vapour pressure deficit inside the chamber (VPDL) was tested for both genotypes and showed a negative influence of the latter on the stomatal behavior and consequently on A. Such effect was more pronounced in BGD than in MYD. These and others relationships involving leaf gas exchange and microclimatic variables in coconut palm trees are discussed

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Incorporating non-stomatal limitation improves the performance of leaf and canopy models at high vapour pressure deficit

Tree Physiology ◽

10.1093/treephys/tpz103 ◽

2019 ◽

Cited By ~ 1

Author(s):

J Yang ◽

R A Duursma ◽

M G De Kauwe ◽

D Kumarathunge ◽

M Jiang ◽

...

Keyword(s):

Gas Exchange ◽

Primary Production ◽

Vapour Pressure ◽

Leaf Gas Exchange ◽

Gross Primary Production ◽

Vapour Pressure Deficit ◽

Stomatal Limitation ◽

Flow Measurements ◽

Hydraulic Limitation ◽

The Future

Abstract Vapour pressure deficit (D) is projected to increase in the future as temperatures rise. In response to increased D, stomatal conductance (gs) and photosynthesis (A) are reduced, which may result in significant reductions in terrestrial carbon, water, and energy fluxes. It is thus important for gas exchange models to capture the observed responses of gs and A with increasing D. We tested a series of coupled A-gs models against leaf gas exchange measurements from the Cumberland Plain Woodland (Australia), where D regularly exceeds 2 kPa and can reach 8 kPa in summer. Two commonly used A-gs models (Leuning 1995 and Medlyn et al. 2011) were not able to capture the observed decrease in A and gs with increasing D at the leaf scale. To explain this decrease in A and gs, two alternative hypotheses were tested: hydraulic limitation (i.e., plants reduce gs and/or A due to insufficient water supply) and non-stomatal limitation (i.e., downregulation of photosynthetic capacity). We found that the model that incorporated a non-stomatal limitation captured the observations with high fidelity and required the fewest number of parameters. While the model incorporating hydraulic limitation captured the observed A and gs, it did so via a physical mechanism that is incorrect. We then incorporated a non-stomatal limitation into the stand model, MAESPA, to examine its impact on canopy transpiration and gross primary production. Accounting for a non-stomatal limitation reduced the predicted transpiration by ~19%, improving the correspondence with sap flow measurements, and gross primary production by ~14%. Given the projected global increases in D associated with future warming, these findings suggest that models may need to incorporate non-stomatal limitation to accurately simulate A and gs in the future with high D. Further data on non-stomatal limitation at high D should be a priority, in order to determine the generality of our results and develop a widely applicable model.

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

Experimental Agriculture ◽

10.1017/s0014479705003121 ◽

2006 ◽

Vol 42 (2) ◽

pp. 147-164 ◽

Cited By ~ 15

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.

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Leaf Gas Exchange Characteristics of Jatropha as Affected by Nitrogen Supply, Leaf Age and Atmospheric Vapour Pressure Deficit

Journal of Agronomy and Crop Science ◽

10.1111/jac.12000 ◽

2012 ◽

Vol 199 (2) ◽

pp. 144-153 ◽

Cited By ~ 14

Author(s):

A. M. Rajaona ◽

H. Brueck ◽

F. Asch

Keyword(s):

Gas Exchange ◽

Vapour Pressure ◽

Leaf Gas Exchange ◽

Leaf Age ◽

Vapour Pressure Deficit ◽

Nitrogen Supply ◽

Gas Exchange Characteristics

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THE INFLUENCE OF VAPOUR PRESSURE DEFICIT ON LEAF WATER RELATIONS OF COCOS NUCIFERA IN NORTHEAST BRAZIL

Experimental Agriculture ◽

10.1017/s0014479708007096 ◽

2009 ◽

Vol 45 (1) ◽

pp. 93-106 ◽

Cited By ~ 12

Author(s):

E. E. M. PASSOS ◽

C. H. B. A. PRADO ◽

W. M. ARAGÃO

Keyword(s):

Gas Exchange ◽

Water Relations ◽

Vapour Pressure ◽

Leaf Gas Exchange ◽

Cocos Nucifera ◽

Vapour Pressure Deficit ◽

Leaf Water ◽

Northeast Brazil ◽

Leaf Water Relations ◽

Semi Arid

SUMMARYDaily courses of leaf gas exchange and leaf water potential (Ψleaf) of green dwarf coconut palm (Cocos nucifera) were measured in irrigated plantations on the wet coastal plateau and in a dry semi-arid area of northeast Brazil. At both sites, significant correlations were obtained between stomatal conductance (gs) and vapour pressure deficit (VPDair), Ψleaf and VPDair, leaf transpiration (E) and gs, and E-Ψleaf. Despite these similar relationships between sites, stronger correlations involving gs-VPDair and E-Ψleaf were found at the semi-arid site, where whole-plant hydraulic conductance (gp) was correlated significantly with VPDair. In addition, at the semi-arid site, only, the net photosynthesis (PN) was not correlated with E and Ψleaf, and the intrinsic water use efficiency (WUEi) was disconnected from VPDair and Ψleaf. The different behaviour of leaf gas exchange and Ψleaf between sites was probably caused by low gs in response to high VPDair at the semi-arid site. Our results indicate potential for significant alterations in the pattern of leaf gas exchange during future climatic changes with increasing temperature and concomitant increases in VPDair. The atmospheric water stress will probably reinforce the strength of connection among water relation variables (E, Ψleaf, gs, gp, and VPDair), but it will disrupt the linear relationship between net CO2 assimilation and leaf water relations such as PN-E, PN-Ψleaf, WUEi-VPDair and WUEi-Ψleaf.

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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.

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Diurnal variation in gas exchange and nonstructural carbohydrates throughout sugarcane development

Functional Plant Biology ◽

10.1071/fp17268 ◽

2018 ◽

Vol 45 (8) ◽

pp. 865 ◽

Cited By ~ 6

Author(s):

Amanda P. De Souza ◽

Adriana Grandis ◽

Bruna C. Arenque-Musa ◽

Marcos S. Buckeridge

Keyword(s):

Gas Exchange ◽

Diurnal Variation ◽

Growth Regulation ◽

Developmental Stages ◽

Leaf Gas Exchange ◽

Water Status ◽

Vapour Pressure Deficit ◽

Nonstructural Carbohydrates ◽

Saccharum Spp ◽

Diurnal Cycles

Photosynthesis and growth are dependent on environmental conditions and plant developmental stages. However, it is still not clear how the environment and development influence the diurnal dynamics of nonstructural carbohydrates production and how they affect growth. This is particularly the case of C4 plants such as sugarcane (Saccharum spp.). Aiming to understand the dynamics of leaf gas exchange and nonstructural carbohydrates accumulation in different organs during diurnal cycles across the developmental stages, we evaluated these parameters in sugarcane plants in a 12-month field experiment. Our results show that during the first 3 months of development, light and vapour pressure deficit (VPD) were the primary drivers of photosynthesis, stomatal conductance and growth. After 6 months, in addition to light and VPD, drought, carbohydrate accumulation and the mechanisms possibly associated with water status maintenance were also likely to play a role in gas exchange and growth regulation. Carbohydrates vary throughout the day in all organs until Month 9, consistent with their use for growth during the night. At 12 months, sucrose is accumulated in all organs and starch had accumulated in leaves without any diurnal variation. Understanding of how photosynthesis and the dynamics of carbohydrates are controlled might lead to strategies that could increase sugarcane’s biomass production.

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