Responses to Humidity by Stomata of Nicotiana glauca L. And Corylus avellana L. Are Consistent With the Optimization of Carbon Dioxide Uptake With Respect to Water Loss

1980 ◽  
Vol 7 (3) ◽  
pp. 315 ◽  
Author(s):  
GD Farquhar ◽  
ED Schulze ◽  
M Kuppers
Keyword(s):  
Carbon Dioxide ◽  
Boundary Layer ◽  
Gas Exchange ◽  
Water Loss ◽  
Corylus Avellana ◽  
Carbon Gain ◽  
Nicotiana Glauca ◽  
Carbon Dioxide Uptake ◽  
Total Conductance ◽  
Corylus Avellana L

Intact leaves of N. glauca and C. avellana were exposed to a range of humidities and their gas exchange monitored. Rates of transpiration and assimilation of carbon dioxide, and their sensitivities to changes in total conductance (leaf and boundary layer) were determined. The ratio of these sensitivities, δE/δA, remained substantially constant over the range of humidities. The results represent the first experimental support for a recent hypothesis that stomata vary their apertures in such a manner as to keep δE/δA constant, which optimizes carbon gain with respect to water loss.

EFFECTS OF HERBICIDES ON CARBON DIOXIDE UPTAKE BY PINE SEEDLINGS

1967 ◽  
Vol 45 (7) ◽  
pp. 961-971 ◽  
Author(s):  
S. Sasaki ◽  
T. T. Kozlowski
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Soil Surface ◽  
Pinus Resinosa ◽  
Spray Application ◽  
Leaf Color ◽  
Carbon Dioxide Uptake ◽  
Chlorophyll Breakdown ◽  
Pine Seedlings ◽  
Steady Rate

Experiments were conducted on effects of herbicides applied to soil or sprayed on shoots on CO2 uptake of 3-year-old Pinus resinosa Ait. seedlings. When applied to the soil, atrazine, monuron, EPTC, and 2,4-D at 20 lb/ac (soil surface basis) or at 4000 p.p.m. variously decreased absorption of CO2. Monuron checked gas exchange most rapidly, with no CO2 uptake measurable after 10 days. Atrazine and 2,4-D inhibited absorption of CO2 at a steady rate. EPTC caused a delayed inhibition of CO2 uptake. DCPA, CDAA, CDEC, and NPA did not affect gas exchange significantly. Monuron applied as a spray depressed CO2 uptake somewhat faster than the soil-applied herbicide. Very rapid inhibition of CO2 uptake was observed after spray application of 2,4-D or EPTC. Atrazine affected gas exchange similarly when applied as a spray or incorporated in the soil. DCPA, applied as a spray, did not affect absorption of CO2 significantly. Possible reasons for differences in CO2 uptake after spray and soil-application of certain herbicides are discussed. Inert ingredients of EPTC applied as sprays at a concentration of 4000 p.p.m. greatly reduced CO2 absorption 3 days after treatment. However, the rapid early depression of gas exchange was followed by recovery, with no obvious deleterious effects on growth up to 3 months after treatment. Some herbicides checked CO2 absorption without chlorophyll breakdown whereas others did not. Monuron completely inhibited CO2 uptake long before any changes in leaf color were evident. In contrast, depression of CO2 absorption by atrazine and 2,4-D rather closely paralleled development of toxicity symptoms, especially chlorosis. These observations suggested that some herbicides such as monuron affected the photosynthetic mechanism more directly than others such as atrazine, 2,4-D, and EPTC.

Effect of irrigation cut-off strategies on yield, water productivity and gas exchange in a drip-irrigated hazelnut (Corylus avellana L. cv. Tonda di Giffoni) orchard under semiarid conditions

2020 ◽  
Vol 238 ◽  
pp. 106173
Author(s):  
Samuel Ortega-Farias ◽  
Emilio Villalobos-Soublett ◽  
Camilo Riveros-Burgos ◽  
Mauricio Zúñiga ◽  
Luis E. Ahumada-Orellana
Keyword(s):  
Gas Exchange ◽  
Water Productivity ◽  
Corylus Avellana ◽  
Corylus Avellana L ◽  
Semiarid Conditions

scholarly journals Intra-individual variation allows an explicit test of the hygric hypothesis for discontinuous gas exchange in insects

2009 ◽  
Vol 6 (2) ◽  
pp. 274-277 ◽  
Author(s):  
Caroline M. Williams ◽  
Shannon L. Pelini ◽  
Jessica J. Hellmann ◽  
Brent J. Sinclair
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Metabolic Rate ◽  
Water Loss ◽  
Individual Variation ◽  
Loss Reduction ◽  
Total Water ◽  
Explicit Test ◽  
Carbon Dioxide Release ◽  
Flow Through

The hygric hypothesis postulates that insect discontinuous gas exchange cycles (DGCs) are an adaptation that reduces respiratory water loss (RWL), but evidence is lacking for reduction of water loss by insects expressing DGCs under normal ecological conditions. Larvae of Erynnis propertius (Lepidoptera: Hesperiidae) naturally switch between DGCs and continuous gas exchange (CGE), allowing flow-through respirometry comparisons of water loss between the two modes. Water loss was lower during DGCs than CGE, both between individuals using different patterns and within individuals using both patterns. The hygric cost of gas exchange (water loss associated with carbon dioxide release) and the contribution of respiratory to total water loss were lower during DGCs. Metabolic rate did not differ between DGCs and CGE. Thus, DGCs reduce RWL in E. propertius , which is consistent with the suggestion that water loss reduction could account for the evolutionary origin and/or maintenance of DGCs in insects.

scholarly journals NITRATE REDUCTION AND ASSIMILATION IN CHLORELLA

1948 ◽  
Vol 32 (1) ◽  
pp. 93-102 ◽  
Author(s):  
Marian Cramer ◽  
Jack Myers
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Nitrate Reduction ◽  
Relative Rate ◽  
Chlorella Pyrenoidosa ◽  
Carbon Dioxide Production ◽  
Growth Conditions ◽  
Low Light ◽  
Carbon Dioxide Uptake ◽  
Elementary Analysis

1. Nitrate reduction and assimilation have been studied in Chlorella pyrenoidosa under growth conditions by observing effects on the CO2/O2 gas exchange quotient. 2. During assimilation of glucose in the dark, nitrate reduction is noted as an increase in the R.Q. to about 1.6 caused by an increased rate of carbon dioxide production. 3. During photosynthesis at low light intensity nitrate reduction is evidenced by a reduction in the CO2O2 quotient to about 0.7 caused by a decreased rate of carbon dioxide uptake. 4. Chlorella will assimilate nitrogen from either nitrate or ammonia. When both sources are supplied, only ammonia is utilized and no nitrate reduction occurs. It is inferred that under the usual conditions of growth nitrate is reduced only at a rate required for subsequent cellular syntheses. The effect of nitrate reduction on the CO2O2 quotient therefore provides a measure of the relative rate of nitrogen assimilation. 5. Over-all photosynthetic metabolism may be described from elementary analysis of the cells since excretory products are negligible. The gas exchange predicted in this way is in good agreement with the observed CO2/O2 quotients.

Seasonal responses of leaf gas exchange to elevated carbon dioxide in Populusgrandidentata

1992 ◽  
Vol 22 (9) ◽  
pp. 1320-1325 ◽  
Author(s):  
Peter S. Curtis ◽  
James A. Teeri
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Partial Pressure ◽  
Leaf Area ◽  
Leaf Gas Exchange ◽  
Exposure Period ◽  
Initial Slope ◽  
Carbon Gain ◽  
Late Season ◽  
Leaf Weight

Rising atmospheric carbon dioxide concentrations may have important consequences for forest ecosystems. We studied above- and below-ground growth and leaf gas exchange responses of Populusgrandidentata Michx. to elevated CO2 under natural forest conditions over the course of a growing season. Recently emerged P. grandidentata seedlings were grown in native, nutrient-poor soils at ambient and twice ambient (707 μbar (1 bar = 100 kPa)) CO2 partial pressure for 70 days in open-top chambers in northern lower Michigan. Total leaf area and shoot and root dry weight all increased in high CO2 grown plants. Photosynthetic light and CO2 response characteristics were measured 28, 45, and 68 days after exposure to elevated CO2. In ambient grown plants, light saturated assimilation rates increased from day 28 to day 45 and then declined at day 68 (15 September). This late-season decline, typical of senescing Populus leaves, was due both to a decrease in the initial slope of the net CO2 assimilation versus intercellular CO2 partial pressure relationship and to decreased CO2 saturated assimilation rates. Specific leaf nitrogen (mg N•(cm2 leaf area)−1) did not change during this period, although leaf carbon content and leaf weight (mg•cm−2) both increased. In ambient grown plants stomatal conductance also declined at day 68. In contrast, plants grown at elevated CO2 showed no late-season decline in photosynthetic capacity or changes in leaf weight, suggesting a delay in senescence with long-term exposure to high CO2. High CO2 grown plants also maintained photosynthetic sensitivity to increasing Ci throughout the exposure period, while ambient CO2 grown plants were insensitive to Ci above 400 μbar on day 68. These results indicate the potential for direct CO2 fertilization of P. grandidentata in the field and provide evidence for a new mechanism by which elevated atmospheric CO2 could influence seasonal carbon gain.

The Exchange of Oxygen and Carbon Dioxide Across the Gills of Rainbow Trout

1967 ◽  
Vol 46 (2) ◽  
pp. 339-348 ◽  
Author(s):  
D. J. RANDALL ◽  
G. F. HOLETON ◽  
E. DON STEVENS
Keyword(s):  
Carbon Dioxide ◽  
Rainbow Trout ◽  
Gas Exchange ◽  
Oxygen Uptake ◽  
Transfer Factor ◽  
Rate Ratio ◽  
High Capacity ◽  
Salmo Gairdneri ◽  
Moderate Exercise ◽  
Carbon Dioxide Uptake

1. The effectiveness of oxygen uptake by the blood of rainbow trout (Salmo gairdneri) approaches 100%, whereas that for the removal of oxygen from water was only 11-30%. 2. Most of the carbon dioxide is removed from the blood as it passes through the gills, but the effectiveness of carbon dioxide uptake by water is very low, because of the high capacity of water for carbon dioxide compared with oxygen. 3. Moderate exercise had little effect on the effectiveness of gas exchange across the gills. The increased oxygen uptake was facilitated by an increase in the transfer factor of the gills for oxygen. There were small increases in the capacity-rate ratio of blood to water at the gills during moderate exercise. 4. Hypoxia resulted in a marked decrease in the effectiveness of oxygen uptake by the blood, but had little effect on oxygen removal from the water. Gas exchange was facilitated during hypoxia by an increase in transfer factor of the gills, but hindered by an increasing capacity-rate ratio of blood to water at the gills. 5. Gas exchange in an aquatic environment was compared with that in an aerial environment.

Ecological plasticity of nut crops of the collections of the federal scientific center for agroecology RAS

2019 ◽  
pp. 105-115
Author(s):  
А.Ш. Хужахметова
Keyword(s):  
Corylus Avellana ◽  
Taxonomic Composition ◽  
Morphological Features ◽  
Scientific Center ◽  
Significance Level ◽  
Ecological Plasticity ◽  
Protective Forest ◽  
Corylus Avellana L ◽  
Academy Of Sciences ◽  
Trees And Shrubs

Показана актуальность изучения экологической пластичности древесных растений в связи с необходимостью подбора адаптированного видового состава деревьев и кустарников для защитных лесных насаждений в условиях климатических изменений. Установлено, что экологическая пластичность и пределы толерантности растений связаны со свойством организмов адаптироваться к тому или иному диапазону факторов среды. В статье представлен таксономический состав орехоплодных культур коллекций ФНЦ агроэкологии РАН. Это шесть видов рода Juglans: J. regia, J. mandshurica, J. cinerea, J. rupestris, J. ailanthifolia, J. nigra и три вида рода Corylus: С. avellana L., С. аmericana W., сорта С. pontica C. Koch Президент, Футкурами, Черкесский2. Приведены сведения о положительном опыте культивирования Corylus avellana L. в плантационных насаждениях (1,6 га, посадка рядовая, схема размещения 55 м) в условиях южных черноземов. Цель исследований изучить экологическую пластичность орехоплодных кустарников коллекций ФНЦ агроэкологии РАН. На примере родового комплекса Corylus получены материалы по экологической пластичности орехоплодных кустарников в условиях каштановых (кадастр. 34:36:0000:14:0178), светлокаштановых почв (34:34:000000:122 34:34:060061:10). Установлены уровни изменчивости морфологических признаков ассимиляционного аппарата и плодов С. avellana L., сортов С. pontica C. Koch., которые согласуются с зимо и засухоустойчивостью. Кластерный анализ позволил выявить корреляцию признаков при 5 уровне значимости. Для целей защитного лесоразведения и озеленения засушливых районов рекомендованы Corylus avellana и Черкесский2 с выраженной вариабельностью морфологических признаков, которая указывает на их широкую экологическую валентность и адаптационные возможности в рассматриваемых условиях. The urgency of studying the ecological plasticity of woody plants in connection with the need to select an adapted species composition of trees and shrubs for protective forest plantations in the context of climate change is shown. It is established that the ecological plasticity and tolerance range of plants is associated with the ability of organisms to adapt to a particular range of environmental factors. The article presents the taxonomic composition of nut crops in the collections of FSC Agroecology RAS. Six species of Juglans: J. regia, J. mandshurica, J. cinerea, J. rupestris, J. ailanthifolia, J. nigra and three species of the genus Corylus: С. avellana L., С. аmericana W., varieties of C. pontica C. Koch the President, Futkurami, Circassian2. Data on positive experience of cultivation of Corylus avellana L. in plantation plantings (1,6 hectares, landing ordinary, the scheme of placement of 55 m) in the conditions of southern chernozems are given. The purpose of the research is to study the ecological plasticity of nutbearing shrubs of the collections of the Federal scientific center for Agroecology Russian Academy of Sciences. For example, a generic complex Corylus submissions received on the environmental plasticity of nut bushes in the conditions of brown (the cadaster nubmer 34:36:0000:14:0178), light chestnut soils (34:34:000000:122 34:34:060061:10). The levels of variability of morphological features of the assimilation apparatus and fruits of Corylus avellana L., С. pontica C. Koch varieties were established., which are consistent with winter and drought resistance. Cluster analysis revealed the correlation of features at 5 significance level. Corylus avellana and Circassian2 with a pronounced variability of morphological features, which indicates their broad ecological valence and adaptation capabilities in the conditions under consideration, are recommended for the purposes of protective afforestation and greening of dry areas.

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