Effect of Elevated CO2 Concentration on Leaf Photosynthesis in Sanjiang-Deyeuxia angustifolia

2013 ◽  
Vol 726-731 ◽  
pp. 305-309
Author(s):  
Ming Yi Xu ◽  
Ao Xue Wang ◽  
Hong Wei Ni
Keyword(s):  
Stomatal Conductance ◽  
Chlorophyll Content ◽  
Photosynthetic Parameters ◽  
Leaf Photosynthesis ◽  
Short Term ◽  
Deyeuxia Angustifolia ◽  
Different Levels ◽  
Concentration Condition ◽  
Photosynthetic Ability

Deyeuxia angustifolia were grown under three different levels of CO2concentration conditions, 370μmol mol-1(ambient CO2), 550μmol mol-1(elevated CO2) and 700μmol mol-1(elevated CO2) respectively. We investigated the responses of photosynthesis and growth ofD.angustifoliaunder different CO2concentration conditions. Leaf photosynthesis and chlorophyll content were checked. The results showed that the values of net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2concentration (Ci), transpiration (E), chlorophyll content were influenced by the elevated CO2concentrations. The photosynthetic parameters changed in parallel with CO2enrichment. CO2enrichment in short term improved the photosynthetic ability of leaves, whereas the capacity was weakened under long-term elevated CO2concentration condition. The leaves ofD.angustifoliagrown under elevated CO2concentrations at the end of growth, had lower Pn, Gs, Ci, E and chlorophyll content than those grown and measuered under ambient CO2concentration. The results indicated thatD.angustifoliaappeared photosynthetic acclimation.

An Empirical Model of Stomatal Conductance

1984 ◽  
Vol 11 (3) ◽  
pp. 191 ◽  
Author(s):  
GD Farquhar ◽  
SC Wong
Keyword(s):  
Stomatal Conductance ◽  
Empirical Model ◽  
Nitrogen Nutrition ◽  
Leaf Age ◽  
Short Term ◽  
Mathematical Expressions ◽  
Partial Pressures ◽  
Intact Leaves

An empirical model of stomatal conductance is presented. The predictions of conductance correlate with experimental determinations of the responses to several kinds of short-term and long-term perturbations, including irradiance, temperature, CO2 and O2 partial pressures, and leaf age and nitrogen nutrition. The model is not mechanistic and cannot account for the observed functioning of stomata independent of mesophyll. Nevertheless its success in predicting responses in intact leaves means that the mathematical expressions used must be analogous to those describing actual functioning.

scholarly journals The Impact of Long-and Short-Term Strontium Treatment on Metabolites and Minerals in Glycine max

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3825 ◽  
Author(s):  
Hanaka ◽  
Dresler ◽  
Wójciak-Kosior ◽  
Strzemski ◽  
Kováčik ◽  
...  
Keyword(s):  
Glycine Max ◽  
Chlorophyll Content ◽  
Entire Period ◽  
Short Term ◽  
Short Term Exposure ◽  
Applied Dose ◽  
The Impact

The impact of long-term exposure to Sr2+ (LTE, four doses, 43.5 mg Sr2+ per pot, with a total of 174 mg Sr2+ per pot during the entire period of cultivation) and short-term exposure to Sr2+ (STE, one dose, 870 mg Sr2+ per pot four days before harvest) on the content of phytoestrogens and allantoin in soybeans were compared. Sr2+ accumulation, the effect on the concentration of macroelements, and basic physiology were also analyzed. LTE reduced the content of malonyldaidzin and malonylgenistin in the roots (58% and 50% compared to the control, respectively). STE increased the amount of all isoflavones in the stem and genistein in the leaves and decreased the content of malonyldaidzin and malonylgenistin in the leaves (55% and 48% compared to the control, respectively) and roots (69% and 62% of the control, respectively) as well as genistein and coumestrol in the roots (both 50% compared to the control). Sr2+ presence stimulated the accumulation of allantoin in the roots (three-fold higher than in the control), but only STE had similar effects on the shoots. In contrast to LTE, Sr2+ was transported extensively from the roots to the leaves under STE. In comparison to the control, LTE resulted in an increase in the Ca content in the stem by 36%, whereas Ca2+ accumulation in the leaves, stems, and roots increased by 60%, 80%, and 36%, respectively, under STE. Additionally, a significant accumulation of K was found only in the roots of the LTE group. The chlorophyll content did not differ between the treatments. Overall, the production of phytoestrogens and Sr accumulation were affected by both the applied dose and the duration of exposure to Sr.

scholarly journals The influence of length of relationship, gender and age on the relationship intention of short-term insurance clients: an exploratory study

2011 ◽  
Vol 11 (2) ◽  
pp. 139-156 ◽  
Author(s):  
Derik Steyn ◽  
Pierre Mostert ◽  
Jan-Willem De Jager
Keyword(s):  
Relationship Marketing ◽  
Strong Relationship ◽  
Short Term ◽  
Gender And Age ◽  
Term Insurance ◽  
Length Of Relationship ◽  
Gender Display ◽  
The Relationship ◽  
Different Levels

Building long-term relationships with clients is extremely beneficial for organisations. This does not necessarily imply, however, that the clients themselves need or want a long-term relationship with an organisation. Relationship marketing could profitably be looked at from the client’s perspective, at the same time identifying those clients who have a strong relationship intention and would, in fact, like to engage in a long-term relationship with organisations.The objective of this research was to explore whether three aspects relating to clients, that is, the varying lengths of their relationship with organisations, their age and their gender display significantly different levels of relationship intention. Relationship intention is measured in terms of constructs like involvement, expectations, forgiveness, feedback and fear of relationship loss.Non-probability sampling was used in this study, and 114 respondents from the short-terminsurance industry completed self-administered questionnaires. Findings indicate that, for a group of high relationship-intention clients of a short-term insurance organisation, no practically significant discrimination exists on any of the relationship-intention constructs for clients’ length of relationship, gender or age.

An Analysis of the Effects of Repeated Short-Term Soil Water Deficits on Stomatal Conductance to Carbon Dioxide and Leaf Photosynthesis by the Legume Macroptilium atropurpureum Cv. Siratro

1981 ◽  
Vol 8 (3) ◽  
pp. 347 ◽  
Author(s):  
MJ Fisher ◽  
DA Charles-Edwards ◽  
MM Ludlow
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Soil Water ◽  
Water Deficit ◽  
Leaf Water Potential ◽  
Leaf Water ◽  
Mathematical Function ◽  
Leaf Photosynthesis ◽  
Short Term ◽  
Macroptilium Atropurpureum

The response was measured of stomatal conductance and leaf photosynthesis to changing leaf water potential in the legume siratro subjected to a sequence of I-week cycles of increasing soil water deficit followed by watering. The response of stomatal conductance was described using a continuous mathematical function, which is more robust and accurate than the usual discontinuous linear function used to analyse such data. After seven successive cycles of water deficit, there was no apparent adjustment of the short-term response of leaf conductance to leaf water potential.

Seasonality of foliar respiration in two dominant plant species from the Arctic tundra: response to long-term warming and short-term temperature variability

2014 ◽  
Vol 41 (3) ◽  
pp. 287 ◽  
Author(s):  
Mary A. Heskel ◽  
Danielle Bitterman ◽  
Owen K. Atkin ◽  
Matthew H. Turnbull ◽  
Kevin L. Griffin
Keyword(s):  
Carbon Cycling ◽  
Leaf Gas Exchange ◽  
Nitrogen Concentration ◽  
Temperature Variability ◽  
The Arctic ◽  
Photosynthetic Parameters ◽  
Carbon Exchange ◽  
Short Term ◽  
Photosynthesis And Respiration

Direct measurements of foliar carbon exchange through the growing season in Arctic species are limited, despite the need for accurate estimates of photosynthesis and respiration to characterise carbon cycling in the tundra. We examined seasonal variation in foliar photosynthesis and respiration (measured at 20°C) in two field-grown tundra species, Betula nana L. and Eriophorum vaginatum L., under ambient and long-term warming (LTW) conditions (+5°C), and the relationship of these fluxes to intraseasonal temperature variability. Species and seasonal timing drove most of the variation in photosynthetic parameters (e.g. gross photosynthesis (Agross)), respiration in the dark (Rdark) and light (Rlight), and foliar nitrogen concentration. LTW did not consistently influence fluxes through the season but reduced respiration in both species. Alongside the flatter respiratory response to measurement temperature in LTW leaves, this provided evidence of thermal acclimation. The inhibition of respiration by light increased by ~40%, with Rlight : Rdark values of ~0.8 at leaf out decreasing to ~0.4 after 8 weeks. Though LTW had no effect on inhibition, the cross-taxa seasonal decline in Rlight : Rdark greatly reduced respiratory carbon loss. Values of Rlight : Agross decreased from ~0.3 in both species to ~0.15 (B. nana) and ~0.05 (E. vaginatum), driven by decreases in respiratory rates, as photosynthetic rates remained stable. The influence of short-term temperature variability did not exhibit predictive trends for leaf gas exchange at a common temperature. These results underscore the influence of temperature on foliar carbon cycling, and the importance of respiration in controlling seasonal carbon exchange.

Stomatal conductance in Cucumis sativus upon short-term and long-term exposures to low temperatures

2012 ◽  
Vol 59 (5) ◽  
pp. 696-699 ◽  
Author(s):  
E. N. Ikkonen ◽  
T. G. Shibaeva ◽  
M. I. Sysoeva ◽  
E. G. Sherudilo
Keyword(s):  
Stomatal Conductance ◽  
Cucumis Sativus ◽  
Low Temperatures ◽  
Short Term

Effect of the soil water content on Jatropha seedlings in a tropical climate

2013 ◽  
Vol 27 (3) ◽  
pp. 351-357 ◽  
Author(s):  
A. Pérez-Vázquez ◽  
G. Hernández-Salinas ◽  
C. Ávila-Reséndiz ◽  
O.A. Valdés-Rodríguez ◽  
F. Gallardo-López ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Stomatal Conductance ◽  
Water Content ◽  
Soil Water ◽  
Chlorophyll Content ◽  
Soil Water Content ◽  
Photosynthetic Rate ◽  
Dry Matter ◽  
Number Of Leaves ◽  
Different Levels

Abstract The purpose of this study was to evaluate growth, chlorophyll content, and photosynthesis in Jatropha at different levels of soil moisture. Plants were cultivated in containers and the treatments of the soil water content evaluated were: 0% (without watering), 20, 40, 60, and 80% soil water content. Plant height was statistically similar for all treatments, but the number of leaves differed significantly. Total dry matter and chlorophyll at 40, 60, and 80% soil water content were statistically similar, but different from 0 and 20% soil water content. Leaf area at 40, 60, and 80% soil water content was statistically different from 0 and 20% soil water content. The photosynthetic rate, transpiration and stomatal conductance at 60 and 80% soil water content were statistically similar but different from 0 and 20% soil water content. Water stress affected growth, chlorophyll content, photosynthetic rate, transpiration, and stomatal conductance.

scholarly journals Competition, Debt Maturity, and Adjustment Speed in China: A Dynamic Fractional Estimation Approach

2020 ◽  
Vol 13 (5) ◽  
pp. 106
Author(s):  
Sultan Sikandar Mirza ◽  
Tanveer Ahsan ◽  
Raheel Safdar ◽  
Ajid Ur Rehman
Keyword(s):  
Capital Structure ◽  
Limited Liability ◽  
Large Firms ◽  
Short Term ◽  
Listed Firms ◽  
Competitive Environments ◽  
Structure Adjustment ◽  
Different Levels ◽  
Unbalanced Panel Data

The purpose of this study was to investigate the capital structure adjustment rate in different levels of product market competitions. We classified Chinese non-financial listed firms into highly, moderately, and less competitive firms and applied an unbiased dynamic panel fractional estimator on unbalanced panel data of 10,941 firm-year observations during the period of 1998 to 2015. We find that the adjustment rate of highly and less competitive firms towards long-term target capital structure is higher (28.2–29.1%) as compared to the adjustment rate towards short-term target capital structure (18.8–18.9%). On the other hand, the adjustment rate of moderately competitive firms towards long-term target capital structure is slower (22.3%) as compared to the adjustment rate towards short-term target capital structure (25.3%). Further, the adjustment rate of highly and less competitive firms differs significantly between long-term and short-term target capital structure, while the adjustment rate of moderately competitive firms remains steady. Highly competitive large firms follow the limited liability model to adjust their target capital structure and support trade-off theory, while both small and large firms follow the limited liability and predation models in moderately and less competitive environments, respectively.

scholarly journals Ozone Amplifies Water Loss from Mature Trees in the Short Term But Decreases It in the Long Term

Forests ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 46
Author(s):  
Elena Paoletti ◽  
Nancy E. Grulke ◽  
Rainer Matyssek
Keyword(s):  
Steady State ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Loss ◽  
Vapour Pressure Deficit ◽  
Environmental Parameters ◽  
Mechanistic Explanation ◽  
Short Term ◽  
Mature Trees

We measured whole-tree transpiration of mature Fagus sylvatica and Picea abies trees exposed to ambient and twice-ambient O3 regimes (1xO3 and 2xO3 free-air fumigation). After eight years, mean daily total transpiration did not vary with the O3 regime over the 31 days of our study, even though individual daily values increased with increasing daily O3 peaks in both species. Although the environmental parameters were similar at 1xO3 and 2xO3, the main factors affecting daily transpiration were vapour pressure deficit in 2xO3 spruce and O3 peaks in beech. For a mechanistic explanation, we measured O3-induced sluggish stomatal responses to variable light (sunflecks) by means of leaf-level gas exchange measurements only in the species where O3 was a significant factor for transpiration, i.e., beech. Stomata were always slower in closing than in opening. The 2xO3 stomata were slower in opening and mostly in closing than 1xO3 stomata, so that O3 uptake and water loss were amplified before a steady state was reached. Such delay in the stomatal reaction suggests caution when assessing stomatal conductance under O3 pollution, because recording gas exchange at the time photosynthesis reached an equilibrium resulted in a significant overestimation of stomatal conductance when stomata were closing (ab. 90% at 1xO3 and 250% at 2xO3). Sun and shade leaves showed similar sluggish responses, thus suggesting that sluggishness may occur within the entire crown. The fact that total transpiration was similar at 1xO3 and 2xO3, however, suggests that the higher water loss due to stomatal sluggishness was offset by lower steady-state stomatal conductance at 2xO3. In conclusion, O3 exposure amplified short-term water loss from mature beech trees by slowing stomatal dynamics, while decreased long-term water loss because of lower steady-state stomatal conductance. Over the short term of this experiment, the two responses offset each other and no effect on total transpiration was observed.

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