Variations in leaf temperature, plant internal resistance, photon   requirement and transpiration of pigeonpea under  bare and mulched soil conditions

ABSTRACT. The paper presents the results of an experiment conducted during 1992 and 1993 crop seasons at the farm of Gujarat Agricultural University, Anand on pigeonpea to determine variations in agro-meteorological characteristics of leaf transpiration leaf temperature plant diffusive resistance and quanta were considered at three levels within the crop canopy in mulched and unmulched fields. The anlilysis rewaled that leaf temperature is more in unmulched field where transpiration rates are lower than the mulched field. Stomatal resistance and the quantum requirements nearly match in both the treatments. Stomatal conductance attains large values in morning and evening hours.

Download Full-text

Kaolin Particle Film Applications Can Increase Photosynthesis and Water Use Efficiency of `Ruby Red' Grapefruit Leaves

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.128.1.0107 ◽

2003 ◽

Vol 128 (1) ◽

pp. 107-112 ◽

Cited By ~ 58

Author(s):

John L. Jifon ◽

James P. Syvertsen

Keyword(s):

Stomatal Conductance ◽

Water Use Efficiency ◽

Water Use ◽

Leaf Temperature ◽

Citrus Paradisi ◽

Photoinhibition Of Photosynthesis ◽

High Radiation ◽

Leaf Transpiration ◽

Partial Pressures ◽

Use Efficiency

Effects of foliar sprays of a kaolin clay particle film (Surround WP) on leaf temperature (Tlf), net gas exchange, chlorophyll fluorescence and water relations of sun-exposed leaves on field-grown grapefruit trees (Citrus paradisi L.) were studied during Summer and Fall 2001. Trees were sprayed twice a week for 3 weeks with aqueous suspensions of kaolin (Surround) at 60 g·L-1. Physiological effects of kaolin application were most prominent around midday on warm sunny days than in mornings, evenings or cloudy days. Kaolin sprays increased leaf whiteness (62%), reduced midday leaf temperature (Tlf; ≈3 °C) and leaf to air vapor pressure differences (VPD; ≈20%) compared to water-sprayed control leaves. Midday reductions in Tlf and VPD were accompanied by increased stomatal conductance (gs) and net CO2 assimilation rates (ACO2) of kaolin sprayed leaves, suggesting that gs might have limited ACO2 in water-sprayed control leaves. Midday photoinhibition of photosynthesis was 30% lower in kaolin-sprayed leaves than in control leaves. Midday water use efficiency (WUE) of kaolin-sprayed leaves was 25% higher than that of control leaves. However, leaf transpiration and whole-tree water use were not affected by kaolin film sprays. Increased WUE was therefore, due to higher ACO2. Leaf intercellular CO2 partial pressures (Ci) were similar in control and kaolin-sprayed leaves indicating that stomatal conductance was not the major cause of reduced ACO2. These results demonstrate that kaolin sprays could potentially increase grapefruit leaf carbon uptake efficiency under high radiation and temperature stress.

Download Full-text

Decline of vegetative growth in Coffea arabica L. in relation to leaf temperature, water potential and stomatal conductance

Field Crops Research ◽

10.1016/s0378-4290(97)00045-2 ◽

1997 ◽

Vol 54 (1) ◽

pp. 65-72 ◽

Cited By ~ 38

Author(s):

Raimundo S. Barros ◽

Jay Wallace da S.e Mota ◽

Fábio M. Da Matta ◽

Moacyr Maestri

Keyword(s):

Stomatal Conductance ◽

Water Potential ◽

Vegetative Growth ◽

Coffea Arabica ◽

Leaf Temperature ◽

Coffea Arabica L ◽

Temperature Water

Download Full-text

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

Experimental Agriculture ◽

10.1017/s0014479700023802 ◽

1994 ◽

Vol 30 (1) ◽

pp. 1-16 ◽

Cited By ~ 13

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.

Download Full-text

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

Sustainability ◽

10.3390/su10114063 ◽

2018 ◽

Vol 10 (11) ◽

pp. 4063 ◽

Cited By ~ 2

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.

Download Full-text

Measurements of nitrogen oxides and ozone fluxes by eddy covariance at a meadow: evidence for an internal leaf resistance to NO<sub>2</sub>

Biogeosciences ◽

10.5194/bg-10-5997-2013 ◽

2013 ◽

Vol 10 (9) ◽

pp. 5997-6017 ◽

Cited By ~ 17

Author(s):

P. Stella ◽

M. Kortner ◽

C. Ammann ◽

T. Foken ◽

F. X. Meixner ◽

...

Keyword(s):

Eddy Covariance ◽

A Priori ◽

Terrestrial Ecosystems ◽

Stomatal Resistance ◽

Internal Resistance ◽

Ozone Production ◽

Deposition Flux ◽

Eddy Covariance Method ◽

Large Variability ◽

Leaf Resistance

Abstract. Nitrogen dioxide (NO2) plays an important role in atmospheric pollution, in particular for tropospheric ozone production. However, the removal processes involved in NO2 deposition to terrestrial ecosystems are still the subject of ongoing discussion. This study reports NO2 flux measurements made over a meadow using the eddy covariance method. The measured NO2 deposition fluxes during daytime were about a factor of two lower than a priori calculated fluxes using the Surfatm model without taking into account an internal (also called mesophyllic or sub-stomatal) resistance. Neither an underestimation of the measured NO2 deposition flux due to chemical divergence or an in-canopy NO2 source nor an underestimation of the resistances used to model the NO2 deposition explained the large difference between measured and modelled NO2 fluxes. Thus, only the existence of the internal resistance could account for this large discrepancy between model and measurements. The median internal resistance was estimated to be 300 s m−1 during daytime, but exhibited a large variability (100–800 s m−1). In comparison, the stomatal resistance was only around 100 s m−1 during daytime. Hence, the internal resistance accounted for 50–90% of the total leaf resistance to NO2. This study presents the first clear evidence and quantification of the internal resistance using the eddy covariance method; i.e. plant functioning was not affected by changes of microclimatological (turbulent) conditions that typically occur when using enclosure methods.

Download Full-text

Stomatal Conductance and Chlorophyll Characteristics and Their Relationship with Yield of Some Cocoa Clones Under Tectona grandis, Leucaena sp., and Cassia surattensis.

Pelita Perkebunan (a Coffee and Cocoa Research Journal) ◽

10.22302/iccri.jur.pelitaperkebunan.v31i2.165 ◽

2015 ◽

Vol 31 (2) ◽

pp. 99-108

Author(s):

Fakhrusy Zakariyya ◽

Adi Prawoto

Keyword(s):

Stomatal Conductance ◽

Chlorophyll Content ◽

Tectona Grandis ◽

High Yield ◽

Climate Type ◽

Pod Yield ◽

Yield And Quality ◽

Diffusive Resistance ◽

Cocoa Production

An optimum physiological condition will support high yield and quality of cocoa production. The research was aimed to study the effects of stomatal conductance and chlorophyll content related to cocoa production under three shade regimes.This research was conducted in Kaliwining Experimental Station, elevation of 45 m above sea level with D climate type based on Schmidt & Fergusson. Cocoa trees which were planted in 1994 at a spacing of 3 X 3 m were used in the study planted by using split plot design. The shade tree species were teak (Tectona grandis), krete (Cassiasurattensis), and lamtoro (Leucaena sp.) as the main plots, and cocoa clones of Sulawesi 01,Sulawesi 02, KKM 22 and KW 165 as sub plots. This study showed that there was interaction between cocoa clone and shade species for stomatal conductance where stomatal diffusive resistance of KKM 22 was the best under Leucaena sp.and Cassiasurattensis with the values of 1.38 and 1.34 s.cm -1, respectively. The highest chlorophyll content, stomatal index and transpiration values was under Leucaena sp. shade. There was positive correlation between chlorophyll content and transpiration with pod yield of cocoa. The highest yield and the lowest bean count wereobtainedon Sulawesi 01 clone under Leucaenasp. shade.Keywords: stomatal conductance, transpiration, diffusive resistance, shades trees, clones,pod yield

Download Full-text

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

PLoS ONE ◽

10.1371/journal.pone.0260960 ◽

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.

Download Full-text

Environmental controls over methanol emission from leaves

Biogeosciences Discussions ◽

10.5194/bgd-4-2593-2007 ◽

2007 ◽

Vol 4 (4) ◽

pp. 2593-2640 ◽

Cited By ~ 3

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.

Download Full-text

Growth and grain yield of eight maize hybrids is aligned with water transport, stomatal conductance, and photosynthesis in a semi-arid irrigated system

10.1101/2021.02.04.429760 ◽

2021 ◽

Author(s):

Sean M Gleason ◽

Lauren Nalezny ◽

Cameron Hunter ◽

Robert Bensen ◽

Satya Chintamanani ◽

...

Keyword(s):

Stomatal Conductance ◽

Grain Yield ◽

Water Transport ◽

Co2 Assimilation ◽

Specific Conductance ◽

Soil Conditions ◽

Transport Pathway ◽

Crop Species ◽

Leaf Level ◽

Improved Performance

There is increasing interest in understanding how trait networks can be manipulated to improve the performance of crop species. Working towards this goal, we have identified key traits linking the acquisition of water, the transport of water to the sites of evaporation and photosynthesis, stomatal conductance, and growth across eight maize hybrid lines grown under well-watered and water-limiting conditions in Northern Colorado. Under well-watered conditions, well-performing hybrids exhibited high leaf-specific conductance, low operating water potentials, high rates of midday stomatal conductance, high rates of net CO2 assimilation, greater leaf osmotic adjustment, and higher end-of-season growth and grain yield. This trait network was similar under water-limited conditions with the notable exception that linkages between water transport, midday stomatal conductance, and growth were even stronger than under fully-watered conditions. The results of this experiment suggest that similar trait networks might confer improved performance under contrasting climate and soil conditions, and that efforts to improve the performance of crop species could possibly benefit by considering the water transport pathway within leaves, as well as within the whole-xylem, in addition to root-level and leaf-level traits.

Download Full-text