scholarly journals Leaf Temperature and Vapour Pressure Deficit (VPD) Driving Stomatal Conductance and Biochemical Processes of Leaf Photosynthetic Rate in a Subtropical Evergreen Coniferous Plantation

2018 ◽  
Vol 10 (11) ◽  
pp. 4063 ◽  
Author(s):  
Yue Li ◽  
Lei Zhou ◽  
Shaoqiang Wang ◽  
Yonggang Chi ◽  
Jinghua Chen
Keyword(s):  
Stomatal Conductance ◽  
Photosynthetic Rate ◽  
Vapour Pressure Deficit ◽  
Leaf Temperature ◽  
Slash Pine ◽  
Seasonal Patterns ◽  
Subtropical China ◽  
Biochemical Processes ◽  
Leaf Photosynthetic Rate ◽  
Positive Effect

Photosynthesis is arguably the most important biochemical process on Earth, which is dramatically influenced by environmental conditions. How environmental factors drive stomatal conductance and biochemical processes of leaf photosynthetic rate has not been sufficiently investigated in subtropical China. In this study, we analysed the effects of stomatal and biochemical parameters on the photosynthetic rate of native Masson’s pine (Pinus massoniana Lamb.) and exotic slash pine (Pinus elliottii Engelm.) in response to leaf temperature and vapour pressure deficit (VPD) in subtropical China, based on leaf gas exchange measurements in 2016. Our results showed that there was no significant difference in the light-saturated photosynthetic rate (Asat) between native Masson’s pine and exotic slash pine. The seasonal patterns of maximum rate of the carboxylation (Vcmax25) were basically consistent with seasonal patterns of Asat for both species. The positive effect of leaf temperature on Asat was mainly produced through its positive effect on Vcmax25. Leaf temperature had no significant effect on stomatal conductance. Vcmax25 and gs simultaneously affected Asat in response to VPD. Our results highlighted the importance of biochemical processes in limiting leaf photosynthetic rate in response to environmental conditions in subtropical evergreen coniferous plantations.

Effects of Clone and Irrigation on the Stomatal Conductance and Photosynthetic Rate of Tea (Camellia sinensis)

1994 ◽  
Vol 30 (1) ◽  
pp. 1-16 ◽  
Author(s):  
B. Gail Smith ◽  
Paul J. Burgess ◽  
M. K. V. Carr
Keyword(s):  
Stomatal Conductance ◽  
Camellia Sinensis ◽  
Photosynthetic Rate ◽  
Leaf Temperature ◽  
Temperature Optimum ◽  
Photosynthetic Rates ◽  
Clone Selection ◽  
Treatment Interaction ◽  
Dry Seasons ◽  
The Relationship

SummaryStomatal conductances (g) and photosynthetic rates (A) were monitored in six tea clones planted in a clone X irrigation experiment in the Southern Highlands of Tanzania. Measurements were made during the warm dry seasons of 1989 and 1990. There was no genotype X treatment interaction in the response in A or g of the various clones to irrigation. Irrigation increased A more than it increased g. Irrigation also increased the temperature optimum for photosynthesis and decreased photo-inhibition at high illuminance. Clones differed in g and A, and in the relationship between leaf temperature and A. The implications of these findings for clone selection are discussed.

Barley and Its Environment. VII. Relationships Between Irradiance, Leaf Photosynthetic Rate and Stomatal Conductance

1977 ◽  
Vol 14 (1) ◽  
pp. 293 ◽  
Author(s):  
P. V. Biscoe ◽  
L. D. Incoll ◽  
E. J. Littleton ◽  
J. H. Ollerenshaw
Keyword(s):  
Stomatal Conductance ◽  
Photosynthetic Rate ◽  
Leaf Photosynthetic Rate

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 Ozone damage, detoxification and the role of isoprenoids – new impetus for integrated models

2016 ◽  
Vol 43 (4) ◽  
pp. 324 ◽  
Author(s):  
Supriya Tiwari ◽  
Rüdiger Grote ◽  
Galina Churkina ◽  
Tim Butler
Keyword(s):  
Stomatal Conductance ◽  
Environmental Conditions ◽  
Economic Losses ◽  
Plant Responses ◽  
Damage Scenarios ◽  
Biochemical Processes ◽  
Wide Range ◽  
Defence Responses ◽  
High Concentrations ◽  
The Impact

High concentrations of ozone (O3) can have significant impacts on the health and productivity of agricultural and forest ecosystems, leading to significant economic losses. In order to estimate this impact under a wide range of environmental conditions, the mechanisms of O3 impacts on physiological and biochemical processes have been intensively investigated. This includes the impact on stomatal conductance, the formation of reactive oxygen species and their effects on enzymes and membranes, as well as several induced and constitutive defence responses. This review summarises these processes, discusses their importance for O3 damage scenarios and assesses to which degree this knowledge is currently used in ecosystem models which are applied for impact analyses. We found that even in highly sophisticated models, feedbacks affecting regulation, detoxification capacity and vulnerability are generally not considered. This implies that O3 inflicted alterations in carbon and water balances cannot be sufficiently well described to cover immediate plant responses under changing environmental conditions. Therefore, we suggest conceptual models that link the depicted feedbacks to available process-based descriptions of stomatal conductance, photosynthesis and isoprenoid formation, particularly the linkage to isoprenoid models opens up new options for describing biosphere-atmosphere interactions.

scholarly journals Exploration of physiological and biochemical processes of canola with exogenously applied fertilizers and plant growth regulators under drought stress

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260960
Author(s):  
Muhammad Mahran Aslam ◽  
Fozia Farhat ◽  
Mohammad Aquil Siddiqui ◽  
Shafquat Yasmeen ◽  
Muhammad Tahir Khan ◽  
...  
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Stomatal Conductance ◽  
Plant Growth ◽  
Stability Index ◽  
Leaf Temperature ◽  
Membrane Stability Index ◽  
Chemical Fertilizers ◽  
Chlorophyll Contents ◽  
Water Contents

Environmental stresses may alter the nutritional profile and economic value of crops. Chemical fertilizers and phytohormones are major sources which can enhance the canola production under stressful conditions. Physio-biochemical responses of canola altered remarkably with the use of nitrogen/phosphorus/potassium (N/P/K) fertilizers and plant growth regulators (PGRs) under drought stress. The major aim of current study was to evaluate nutritional quality and physio-biochemical modulation in canola (Brassica napus L.) from early growth to seed stage with NPK and PGRs in different water regimes. To monitor biochemical and physiological processes in canola, two season field experiment was conducted as spilt plot under randomized complete block design (RCBD) with four treatments (Control, Chemical fertilizers [N (90 kg/ha), P and K (45 kg ha-1)], PGRs; indole acetic acid (IAA) 15g ha-1, gibberellic acid (GA3) 15g ha-1 and the combination of NPK and PGRs] under different irrigations regimes (60, 100, 120, 150 mm evaporations). Water stress enhanced peroxidase (POD), catalase (CAT), superoxide dismutase (SOD), polyphenol oxidase (PPO), soluble sugar, malondialdehyde (MDA), proline contents as well as leaf temperature while substantially reduced leaf water contents (21%), stomatal conductance (50%), chlorophyll contents (10–67%), membrane stability index (24%) and grain yield (30%) of canola. However, the combined application of NPK and PGR further increased the enzymatic antioxidant pool, soluble sugars, along with recovery of leaf water contents, chlorophyll contents, stomatal conductance and membrane stability index but decreased the proline contents and leaf temperature at different rate of evaporation. There is positive interaction of applied elicitors to the water stress in canola except leaf area. The outcomes depicted that the combination of NPK with PGRs improved the various morpho-physiological as well as biochemical parameters and reduced the pressure of chemical fertilizers cost about 60%. It had also reduced the deleterious effect of water limitation on the physiology and grain yield and oil contents of canola in field experiments.

scholarly journals Environmental controls over methanol emission from leaves

2007 ◽  
Vol 4 (4) ◽  
pp. 2593-2640 ◽  
Author(s):  
P. Harley ◽  
J. Greenberg ◽  
Ü. Niinemets ◽  
A. Guenther
Keyword(s):  
Stomatal Conductance ◽  
Leaf Growth ◽  
Dry Mass ◽  
Leaf Temperature ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Emission Model ◽  
Production Term ◽  
Methanol Production ◽  
Environmental Controls

Abstract. Methanol is found throughout the troposphere, with average concentrations second only to methane among atmospheric hydrocarbons. Proposed global methanol budgets are highly uncertain, but all agree that at least 60% of the total source arises from the terrestrial biosphere and primary emissions from plants. However, the magnitude of these emissions is also highly uncertain, and the environmental factors which control them require further elucidation. Using a temperature-controlled leaf enclosure, we measured methanol emissions from leaves of six plant species by proton transfer reaction mass spectrometry, with simultaneous measurements of leaf evapotranspiration and stomatal conductance. Rates of emission at 30°C varied from 0.3 to 38 μg g (dry mass)−1 h−1, with higher rates measured on young leaves, consistent with the production of methanol via pectin demethylation in expanding foliage. On average, emissions increased by a factor of 2.4 for each 10°C increase in leaf temperature. At constant temperature, emissions were also correlated with co-varying incident photosynthetic photon flux density and rates of stomatal conductance. The data were analyzed using the emission model developed by Niinemets and Reichstein (2003a, b), with the incorporation of a methanol production term that increased exponentially with temperature. It was concluded that control of emissions, during daytime, was shared by leaf temperature and stomatal conductance, although rates of production may also vary diurnally in response to variations in leaf growth rate in expanding leaves. The model, which generally provided reasonable simulations of the measured data during the day, significantly overestimated emissions on two sets of measurements made through the night, suggesting that production rates of methanol were reduced at night, perhaps because leaf growth was reduced or possibly through a direct effect of light on production. Although the short-term dynamics of methanol emissions can be successfully modeled only if stomatal conductance and compound solubility are taken into account, emissions on longer time scales will be determined by rates of methanol production, controls over which remain to be investigated.

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