TEMPERATURE AND STOMATAL RESISTANCE OF SOYBEAN LEAVES

1979 ◽  
Vol 59 (1) ◽  
pp. 153-162 ◽  
Author(s):  
C. R. SUMAYAO ◽  
E. T. KANEMASU
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Air Temperature ◽  
Canopy Temperature ◽  
Temperature Inversion ◽  
Stomatal Resistance ◽  
Leaf Temperature ◽  
First Case ◽  
Soybean Leaves

A field study was conducted during the 1977 growing season to determine the effect of soil-water content on the air temperature within and above the soybean canopy and consequently on the leaf temperature and stomatal resistance of soybeans (Glycine max L. ’Calland’). Leaf temperature at two heights and air temperature at five heights within and above the canopy were measured with copper-constantan thermocouples while stomatal resistances were measured with an automatic porometer. At soil-water depletions <65%, a daytime air-temperature inversion occurred within and above the canopy, while at depletions >65% air temperature decreased with height. In the first case the canopy temperature was cooler than the air above the canopy when air temperature exceeded 32 °C and the lower canopy leaves were cooler than the upper canopy leaves when they were completely shaded by the upper leaves. At soil-water depletions greater than 65% the canopy was warmer than the air and the lower canopy leaves were warmer than the upper canopy leaves. Stomatal resistance, on the other hand, decreased with height within the canopy irrespective of soil-water content.

EPICUTICULAR WAX PRODUCTION, WATER STATUS AND LEAF TEMPERATURE IN TRITICEAE RANGE GRASSES OF CONTRASTING VISIBLE GLAUCOUSNESS

1989 ◽  
Vol 69 (2) ◽  
pp. 513-519 ◽  
Author(s):  
P. G. JEFFERSON ◽  
D. A. JOHNSON ◽  
K. H. ASAY
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Epicuticular Wax ◽  
Leaf Temperature ◽  
Leaf Water ◽  
Total Biomass ◽  
Crested Wheatgrass ◽  
Intermediate Wheatgrass ◽  
Wax Production

Studies were conducted to compare the effect of glaucousness on the response of perennial range grasses to drought stress. Glaucous and nonglaucous plants of an intermediate wheatgrass hybrid (Thinopyrum intermedium (Host) Barkworth and D. R. Dewey × T. intermedium-acutum D.R. Dewey pers. commun.) and an interspecific hybrid of crested wheatgrass (induced tetraploid Agropyron cristatum (L.) Gaertner s. lat. × A. desertorum (Fisch. ex Link) Schultes) were studied in field nurseries for epicuticular wax production, leaf water potential, leaf reflectance of radiation and leaf temperature. Glaucous plants of intermediate wheatgrass had higher epicuticular wax production, increased leaf reflection of radiation, lower midday canopy temperatures, and higher predawn leaf water potentials than non-glaucous plants. Similar trends were observed for the crested wheatgrass hybrids except that glaucousness did not affect midday plant temperatures. A greenhouse experiment involved comparison of glaucous and non-glaucous synthetics of Altai wild ryegrass (Leymus angustus (Trin.) Pilger Dewey). Leaves of glaucous Altai wild ryegrass reflected more radiation and used water less efficiently (total biomass basis) at high soil water content than leaves of the nonglaucous synthetic. At low soil water content, glaucous Altai wild ryegrass had higher leaf temperature and higher midday leaf water potential. Glaucous and nonglaucous Altai synthetics did not differ significantly for shoot yield, total biomass yield, and water use efficiency (shoot yield basis) at either soil water content. While glaucousness may affect water relations of these grasses, it does not necessarily affect forage yield.Key words: Water use efficiency, drought stress, leaf radiation reflectance, crested wheatgrass, intermediate wheatgrass, Altai wild ryegrass

scholarly journals PERANAN EKOLOGI DUSUNG DAN NON DUSUNG DAN KONTRIBUSINYA PADA KONSERVASI LINGKUNGAN DI DESA URENG KECAMATAN LEIHITU KABUPATEN MALUKU TENGAH

2018 ◽  
Vol 2 (1) ◽  
pp. 28-48
Author(s):  
Napsiah Heluth ◽  
J. Matinahoru ◽  
Fransina Latumahina
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Air Temperature ◽  
Organic Content ◽  
Environmental Conservation ◽  
Soil Macrofauna ◽  
Organic C

The research study aims to determine the ecological conditions of dusung and non dusung, and the role of the contribution to environmental conservation in Ureng Village. The research method used was purposive sampling with observation parameters were microclimate (CO2 content, air temperature, humidity), vegetation conditions and soil conditions (soil temperature, soil moisture, soil pH, soil moisture content, soil macrofauna and organic C) . The results of  Paired of each parameter measured mostly show a smaller calculated t value compared to the t0.05 table value (1.8595) which means that the parameter is not a real difference, ie for the air humidity, t count = 0.27,; soil pH, t count = 0.6; soil macrofauna, t count = -0.66 and vegetation, t count = 1.01. As for the parameters of CO2; air temperature, soil temperature, , soil water content and organic C, t value of CO2 gives the value t count = - 16.06; air temperature = -5.11; soil temperature = -3.62; soil moisture, t count = 2,16; soil water content = 8.47, and C-Organic = 8.53; t count value which is greater than t table value which shows that there is a significant difference between CO2, air temperature, soil temperature, soil moisture, soil water content and C-Organic content in the dusung area which is greater than in the non-dusung area. From the results of the analysis it is known that dusung has a better role in environmental conservation when compared to non dusung which is indicated by the value of CO2 air temperature, soil temperature, soil moisture, soil water content and C-organic content.

scholarly journals Canopy Solar-Induced Chlorophyll Fluorescence and Its Link to Transpiration in a Temperate Evergreen Needleleaf Forest during the Fall Transition

Forests ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 74
Author(s):  
Weiwei Cong ◽  
Kaijie Yang ◽  
Feng Wang
Keyword(s):  
Chlorophyll Fluorescence ◽  
Soil Temperature ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Air Temperature ◽  
Pearson Correlation ◽  
Evergreen Forest ◽  
Spatiotemporal Resolution ◽  
The Relationship

Northern hemisphere evergreen needleleaf forest (ENF) contributes a significant fraction of global water exchange but regional transpiration (T) observation in ENF ecosystems is still challenging. Traditional remote sensing techniques and terrestrial biosphere models reproduce the transpiration seasonality with difficulty, and with large uncertainties. Solar-induced chlorophyll fluorescence (SIF) emission from vegetation correlates to photosynthesis at multiple spatial and temporal scales. However, how SIF links to transpiration of evergreen forest during seasonal transition is unclear. Here, we explored the relationship between canopy SIF and T retrieved from ground observation towers in ENF. We also examined the role of meteorological and soil factors on the relationship between SIF and T. A slow decrease of SIF and T with a fast reduction in photosynthetically active radiation (PAR), air temperature, vapor pressure deficit (VPD), soil temperature and soil water content (SWC) were found in the ENF during the fall transition. The correlation between SIF and T at hourly and daily scales varied significantly among different months (Pearson correlation coefficient = 0.29–0.68, p < 0.01). SIF and T were significantly linearly correlated at hourly (R2 = 0.53, p < 0.001) and daily (R2 = 0.67, p < 0.001) timescales in the October. Air temperature and PAR were the major moderating factors for the relationship between SIF and T in the fall transition. Soil water content (SWC) influenced the SIF-T relationship at an hourly scale. Soil temperature and VPD’s effect on the SIF-T relationship was evident at a daily scale. This study can help extend the possibility of constraining ecosystem T by SIF at an unprecedented spatiotemporal resolution during season transitions.

Evaluation of radiant canopy temperature and soil water measurement for quantifying the contribution of shallow watertables to crop evaporation.

Soil Research ◽  
1990 ◽  
Vol 28 (6) ◽  
pp. 1013 ◽  
Author(s):  
L Mateos ◽  
WS Meyer ◽  
RCG Smith ◽  
R Sides
Keyword(s):  
Heat Flux ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Aerodynamic Resistance ◽  
Sensible Heat Flux ◽  
Canopy Temperature ◽  
Balance Model ◽  
Accurate Estimation ◽  
Clay Loam

Accurate estimation of the contribution of shallow watertables to crop water consumption is of major importance for improved irrigation practice and watertable management. A water balance model based on radiant canopy temperature estimations of crop evaporation and measurements of the change in the soil water content with a neutron probe was used to estimate the net upward flux from the watertable. The model was tested against measurements made by using two weighing lysimeters containing loam and clay loam soils, and the estimation of errors involved was analysed. The watertable in the lysimeters was maintained 1 m below the ground surface. Evaporation from a soybean crop was estimated by using an energy balance model with measured values of net radiant energy and soil heat flux. Sensible heat flux was calculated from the difference between the radiant canopy temperature and air temperature, together with an estimated aerodynamic resistance of the crop. Two sources of error were associated with the model, one due to the estimation of crop evaporation and the other due to the measurement of the change in soil water content. Errors of 0.7 and 5.1 mm per day were estimated for the first and second sources respectively. The accuracy of the method was determined by the length of the period considered and by the contribution of the watertable itself. An error of 20% was estimated when periods of 20 and 80 days were considered in the loam and clay loam soils respectively. Shorter time periods will result in larger uncertainty. The implications of the these results for watertable management are discussed.

scholarly journals Climatic controls on leaf litter decomposition across European forests and grasslands revealed by reciprocal litter transplantation experiments

2016 ◽  
Vol 13 (5) ◽  
pp. 1621-1633 ◽  
Author(s):  
Miguel Portillo-Estrada ◽  
Mari Pihlatie ◽  
Janne F. J. Korhonen ◽  
Janne Levula ◽  
Arnoud K. F. Frumau ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Leaf Area ◽  
Soil Water Content ◽  
Litter Decomposition ◽  
Air Temperature ◽  
Specific Leaf Area ◽  
Future Climate Change ◽  
Precipitation Regimes ◽  
Transplantation Experiments

Abstract. Carbon (C) and nitrogen (N) cycling under future climate change is associated with large uncertainties in litter decomposition and the turnover of soil C and N. In addition, future conditions (especially altered precipitation regimes and warming) are expected to result in changes in vegetation composition, and accordingly in litter species and chemical composition, but it is unclear how such changes could potentially alter litter decomposition. Litter transplantation experiments were carried out across six European sites (four forests and two grasslands) spanning a large geographical and climatic gradient (5.6–11.4 °C in annual temperature 511–878 mm in precipitation) to gain insight into the climatic controls on litter decomposition as well as the effect of litter origin and species. The decomposition k rates were overall higher in warmer and wetter sites than in colder and drier sites, and positively correlated with the litter total specific leaf area. Also, litter N content increased as less litter mass remained and decay went further. Surprisingly, this study demonstrates that climatic controls on litter decomposition are quantitatively more important than species or site of origin. Cumulative climatic variables, precipitation, soil water content and air temperature (ignoring days with air temperatures below zero degrees Celsius), were appropriate to predict the litter remaining mass during decomposition (Mr). Mr and cumulative air temperature were found to be the best predictors for litter carbon and nitrogen remaining during the decomposition. Using mean annual air temperature, precipitation, soil water content and litter total specific leaf area as parameters we were able to predict the annual decomposition rate (k) accurately.

Photosynthesis and Stomatal-Conductance Responses of Johnsongrass (Sorghum halepense) to Water Stress

Weed Science ◽  
1985 ◽  
Vol 33 (5) ◽  
pp. 635-639 ◽  
Author(s):  
Bryan L. Stuart ◽  
Daniel R. Krieg ◽  
John R. Abernathy
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Osmotic Potential ◽  
Grain Filling ◽  
Leaf Temperature ◽  
Sorghum Halepense

The influence of water stress on johnsongrass [Sorghum halepense(L.) Pers. ♯ SORHA] physiology was evaluated in a semiarid environment. Stomatal conductance of johnsongrass responded to more negative leaf water potential and increasing leaf temperature. The sensitivity of the leaf temperature effect was dependent on the soil water content. At low soil water content, conductance was limited by low water potential, and increasing leaf temperature had little effect. Conductance of CO2was related to net photosynthesis in a curvilinear manner, with conductance levels greater than 0.3 mol·m-2· s-1being in excess of that necessary for maximum photosynthesis. At both high conductance levels and low levels associated with increased water stress, intercellular CO2concentration increased, indicating nonstomatal limitations to photosynthesis. Decreased osmotic potential provided the highest correlation with the linear decline of photosynthetic rate as stress intensified. The expression of osmotic adjustment in johnsongrass is reported during grain filling. Plants in the milkdough stage of grain filling had approximately 0.3 MPa lower osmotic potential at any relative water content than those at anthesis.

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