Gas exchange processes of yellow-cedar (Chamaecyparis nootkatensis) in response to environmental variables

1991 ◽  
Vol 69 (12) ◽  
pp. 2684-2691 ◽  
Author(s):  
Steven C. Grossnickle ◽  
John H. Russell
Keyword(s):  
Stomatal Conductance ◽  
Response Surface ◽  
Photosynthetically Active Radiation ◽  
Vapour Pressure ◽  
Vapour Pressure Deficit ◽  
Surface Model ◽  
Root Temperature ◽  
Active Radiation ◽  
Chamaecyparis Nootkatensis ◽  
Exchange Processes

Yellow-cedar (Chamaecyparis nootkatensis (D. Don) Spach) gas exchange processes were measured in response to the following primary environmental variables: photosynthetically active radiation, vapour pressure deficit, root temperature, and soil moisture. Under nonlimiting edaphic conditions, maximum stomatal conductance and maximum CO2 assimilation increased rapidly as photosynthetically active radiation increased from 0 to 200 μmol∙m−2∙s−1 and from 0 to 500 μmol∙m−2∙s−1, respectively. Thereafter, greater photosynthetically active radiation levels only resulted in minor increases in stomatal conductance and CO2 assimilation. Maximum stomatal conductance and maximum CO2 assimilation declined in a concave manner as vapour pressure deficit increased from 1 to 5 kPa. Response surface model for stomatal conductance showed vapour pressure deficit was the primary influence after light had caused initial stomatal opening. Response surface modeling approach showed CO2 assimilation increased as photosynthetically active radiation increased, but increased vapour pressure deficit resulted in a suppression of CO2 assimilation. Response surface model showed internal CO2 concentration declined sharply as photosynthetically active radiation increased from 0 to 500 μmol∙m−2∙s−1, but it remained constant with increasing vapour pressure deficit. Decreasing root temperature resulted in a continual decline in CO2 assimilation and stomatal conductance from 22 to 1 °C, while internal CO2 concentration declined from 22 to 13 °C with little change between 13 and 1 °C. As predawn shoot water potential decreased from −0.5 to −2.0 MPa, CO2 assimilation declined in a linear manner, while stomatal conductance and internal CO2 concentration declined in a concave manner. Key words: Chamaecyparis nootkatensis, CO2 assimilation, stomatal conductance, internal CO2 concentration, photosynthetically active radiation, vapour pressure deficit, root temperature, predawn shoot water potential.

Relationship between Photosynthetic Rate and Stomatal Conductance, Intercellular CO2 Concentration, Transpiration Rate, Vapour Pressure Deficit and Photosynthetically Active Radiation in Sweet Corn (Zea mays)

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Aidee Kamal Khamis ◽  
◽  
Umi Aisah Asli ◽  
Mohd Nadzreen Hidaya Sarjuni ◽  
Mohd Azlan Jalal ◽  
...  
Keyword(s):  
Zea Mays ◽  
Stomatal Conductance ◽  
Photosynthetic Rate ◽  
Transpiration Rate ◽  
Photosynthetically Active Radiation ◽  
Vapour Pressure ◽  
Sweet Corn ◽  
Vapour Pressure Deficit ◽  
Active Radiation ◽  
Development Stages

Sweet corn (Zea mays) is thethird-largest plantation crop in Malaysia. Since it is cultivated mainly for the corncobs, the reproductive and kernel development stages are critical for high yields. Photosynthesis measurement can be used as a major approach to improve photosynthetic efficiency, which can directly affect yield. Additionally, plant nutrient uptake also plays a major role in yield quantity and quality. Conventional fertilisation(chemical and/or organic) may result in excessive fertilizer input, which is detrimental to the environment. We therefore investigated the relationship between photosynthetic rate and stomatal conductance (gs), intercellular CO2concentration (Ci), transpiration rate and vapour pressure deficit based on leaf temperature (VpdL) and photosynthetically active radiation (PAR) during the growth and development stages of sweet corn. The seeds were subjected to the germination test to assess viability and were then planted at a distance of 10 cm both between plantsand rows (replicates). A total of eight subplots (2.2 m long, 60 cm wide, 30 cm high) were prepared in a randomized complete block design (RCBD). Leaf gas exchange measurements were carried out at days 10, 20, 30, 40, 50 and 60 at 9:00 a.m. in the morning and 4:00 p.m. in the evening. Three uniform plants were selected from each replicate and used for measurements throughout the experiment. At day 30, photosynthesis started to decline and was largely unaffected by the set environmental conditions, although stomatal conductance remained high. This can be attributed to the energy diversion from vegetative stages to reproductive stages. Therefore, fertilising practices should be synchronised to match the plant stages for more sustainable and efficient fertilisation and to obtain maximum yield.

scholarly journals TRANSPIRAÇÃO FOLIAR E CONDUTÂNCIA ESTOMÁTICA DA CANA-DE-AÇÚCAR EM FUNÇÃO DO CLIMA E DISPONIBILIDADE DE ÁGUA

Irriga ◽  
2017 ◽  
Vol 22 (4) ◽  
pp. 675-689
Author(s):  
Gustavo Cavalari Barboza ◽  
José Teixeira Filho
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Photosynthetically Active Radiation ◽  
Vapour Pressure Deficit ◽  
Weather Conditions ◽  
Gas Analyzer ◽  
Active Radiation ◽  
Agricultural Engineering ◽  
Leaf Transpiration ◽  
Infrared Gas Analyzer

TRANSPIRAÇÃO FOLIAR E CONDUTÂNCIA ESTOMÁTICA DA CANA-DE-AÇÚCAR EM FUNÇÃO DO CLIMA E DISPONIBILIDADE DE ÁGUA  GUSTAVO CAVALARI BARBOZA¹ E JOSÉ TEIXEIRA FILHO² ¹ Faculdade de Engenharia Agrícola, UNICAMP – Universidade Estadual de Campinas, Cidade Universitária Zeferino Vaz, Campinas- SP – Brasil. CEP:13083-875, [email protected]. ² Faculdade de Engenharia Agrícola, UNICAMP – Universidade Estadual de Campinas, Cidade Universitária Zeferino Vaz, Campinas- SP – Brasil. CEP:13083-875, [email protected].  1 RESUMO Diversos trabalhos utilizam da porometria como metodologia para quantificar a transferência de água para a atmosfera. No entanto, para a cana-de-açúcar essa metodologia é escassa. Assim, o objetivo do trabalho foi verificar o comportamento da transpiração foliar (E) e da condutância estomática (Gs) da cana-de-açúcar em função da radiação fotossinteticamente ativa (PAR) e do deficit de pressão de vapor (DPV), e correlacionar com os diferentes potenciais hídricos das plantas (Ψpd). Esse experimento foi conduzido na área experimental da Faculdade de Engenharia Agrícola da Universidade Estadual de Campinas, no qual foi instalada uma parcela de cana-de-açúcar, variedade RB867515 e utilizado o analisador automático de fotossíntese - IRGA LI6400XT, na escala horária. A partir dos resultados, conclui-se que os valores de E e Gs estão correlacionados positivamente com as condições meteorológicas e também com a disponibilidade de água no solo. Palavras-chave: Trocas gasosas, potencial hídrico foliar, radiação fotossinteticamente ativa.  BARBOZA, G. C.; TEIXEIRA FILHO, J.LEAF TRANSPIRATION AND STOMATAL CONDUCTANCE OF SUGARCANE IN FUNCTION OF WEATHER AND AVAILABILITY OF WATER  2 ABSTRACT There are several studies using porometry as method to quantify the transfer of water to the atmosphere. However, for sugarcane this methodology is scarce. The objective of the study was to investigate the behavior of leaf transpiration (E) and stomatal conductance (Gs) of sugarcane in function of photosynthetically active radiation (PAR) and vapour-pressure deficit (VPD), and to correlate with the different water potential of plants (Ψpd). This experiment was conducted in the experimental area of the Faculty of Agricultural Engineering/UNICAMP, where was installed a parcel of sugarcane, RB867515 variety was installed, and a infrared gas analyzer - IRGA LI6400XT was used in hourly scale. Based on the results, it is concluded that the values of E and Gs are positively correlated with the weather conditions and with the availability of water in the soil. Keywords: Gas Exchange, leaf water potential, photosynthetically active radiation.

scholarly journals A process-based <i>Sphagnum</i> plant-functional-type model for implementation in the TRIFFID Dynamic Global Vegetation Model

2019 ◽  
Author(s):  
Richard Coppell ◽  
Emanuel Gloor ◽  
Joseph Holden
Keyword(s):  
Water Table ◽  
Primary Productivity ◽  
Photosynthetically Active Radiation ◽  
Land Surface ◽  
Net Primary Productivity ◽  
Type Model ◽  
Surface Model ◽  
Dynamic Global Vegetation Model ◽  
Active Radiation ◽  
Global Vegetation

Abstract. Peatlands are important carbon stores and Sphagnum moss represents a critical peatland genus contributing to carbon exchange and storage. However, gas fluxes in Sphagnum-dominated systems are poorly represented in Dynamic Global Vegetation Models (DGVMs) which simulate, via incorporation of Plant Functional Types (PFTs), biogeochemical and energy fluxes between vegetation, the land surface and the atmosphere. Mechanisms characterised by PFTs within DGVMs include photosynthesis, respiration and competition and, in more recent DGVMs, sub-daily gas-exchange processes regulated by leaf 10 stomata. However, Sphagnum, like all mosses, are non-vascular plants and do not exhibit stomatal regulation. In order to achieve a level of process detail consistent with existing vascular vegetation PFTs within DGVMs, this paper describes a new process-based non-vascular-PFT model that is implemented within the TRIFFID DGVM used by the JULES land surface model. The new PFT model was tested against extant published field and laboratory studies of peat assemblage-net primary productivity, assemblage-gross primary productivity, assemblage respiration, water-table position, incoming 15 photosynthetically active radiation, temperature, and canopy dark respiration. The PFT model’s parameters were roughly tuned and the PFT model easily produced curves of the correct shape for peat assemblage-net primary productivity against water-table position, incoming photosynthetically active radiation and temperature, suggesting that it replicates the internal productivity mechanism of Sphagnum for the first time. Minor modifications should also allow it to be used across a range of other bryophytes enabling this non-vascular PFT model to have enhanced functionality.

The interpretation of the variations in leaf water potential and stomatal conductance found in canopies in the field

1976 ◽  
Vol 273 (927) ◽  
pp. 593-610 ◽  
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Vapour Pressure ◽  
Environmental Variables ◽  
Turgor Pressure ◽  
Radiant Energy ◽  
Vapour Pressure Deficit ◽  
Leaf Water ◽  
Scatter Diagram

Attempts to correlate values of stomatal conductance and leaf water potential with particular environmental variables in the field are generally of only limited success because they are simultaneously affected by a number of environmental variables. For example, correlations between leaf water potential and either flux of radiant energy or vapour pressure deficit show a diurnal hysteresis which leads to a scatter diagram if many values are plotted. However, a simple model may be adequate to relate leaf water potential to the flow of water through the plant. The stomatal conductance of illuminated leaves is a function of current levels of temperature, vapour pressure deficit, leaf water potential (really turgor pressure) and ambient CO 2 concentration. Consequently, when plotted against any one of these variables a scatter diagram results. Physiological knowledge of stomatal functioning is not adequate to provide a mechanistic model linking stomatal conductance to all these variables. None the less, the parameters describing the relationships with the variables can be conveniently estimated from field data by a technique of non-linear least squares, for predictive purposes and to describe variations in response from season to season and plant to plant.

Stomatal Responses to Environmental Variables in Shade and Sun Grown Coffee Plants in Mexico

1985 ◽  
Vol 21 (3) ◽  
pp. 249-258 ◽  
Author(s):  
Luis Fanjul ◽  
R. Arreola-Rodriguez ◽  
M. P. Mendez-Castrejon
Keyword(s):  
Stomatal Conductance ◽  
Air Temperature ◽  
Environmental Conditions ◽  
Vapour Pressure ◽  
Environmental Variables ◽  
Vapour Pressure Deficit ◽  
Net Photosynthesis ◽  
Stomatal Movement ◽  
Stomatal Responses ◽  
Coffee Plants

SUMMARYThe influence of air temperature (T), vapour pressure deficit (vpd), irradiance (Q) and leaf water potential (ψ) on diurnal stomatal movement of coffee plants was examined under field and controlled environmental conditions. Leaves of plants grown under shade had larger stomatal conductance (g) values than plants grown in open sun. Stomatal responses to vpd under constant temperature conditions were very strong, indicating that ambient humidity could play a major role in controlling stomatal aperture. Changes in g as vpd increased probably contributed to observed reductions in the rate of net photosynthesis (Pn), though the effect of vpd on Pn was smaller.

scholarly journals Using MODIS derived <i>f</i>PAR with ground based flux tower measurements to derive the light use efficiency for two Canadian peatlands

2008 ◽  
Vol 5 (2) ◽  
pp. 1765-1794 ◽  
Author(s):  
J. Connolly ◽  
N. T. Roulet ◽  
J. W. Seaquist ◽  
N. M. Holden ◽  
P. M. Lafleur ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Photosynthetically Active Radiation ◽  
Vapour Pressure Deficit ◽  
Remote Sensing Data ◽  
Limiting Factor ◽  
Light Use Efficiency ◽  
Active Radiation ◽  
Flux Tower ◽  
Use Efficiency ◽  
Moderate Resolution Imaging Spectroradiometer

Abstract. We used satellite remote sensing data; fraction of photosynthetically active radiation absorbed by vegetation (fPAR) from the Moderate Resolution Imaging Spectroradiometer (MODIS) in combination with tower eddy covariance and meteorological measurements to characterise the light use efficiency parameter (ε) variability and the maximum ε (εmax) for two contrasting Canadian peatlands. Eight-day MODIS fPAR data were acquired for the Mer Bleue (2000 to 2003) and Western Peatland (2004). Flux tower eddy covariance and meteorological measurements were integrated to the same eight-day time stamps as the MODIS fPAR data. A light use efficiency model: GPP=ε * APAR (where GPP is Gross Primary Productivity and APAR is absorbed photosynthetically active radiation) was used to calculated ε. The εmax value for each year (2000 to 2003) at the Mer Bleue bog ranged from 0.58 g C MJ−1 to 0.78 g C MJ−1 and was 0.91 g C MJ−1 in 2004, for the Western Peatland. The average growing season ε for the Mer Bleue bog for the four year period was 0.35 g C MJ−1 and for the Western Peatland in 2004 was 0.57 g C MJ−1. The average snow free period ε for the Mer Bleue bog over the four year period was 0.27 g C MJ−1 and for the Western Peatland in 2004 was 0.39 g C MJ−1. Using the light use efficiency method we calculated the εmax and the annual variability in ε for two Canadian peatlands. We determined that temperature was a growth-limiting factor at both sites Vapour Pressure Deficit (VPD) however was not. MODIS fPAR is a useful tool for the characterization of ε at flux tower sites.

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