scholarly journals Modelling Amazonian forest eddy covariance data: a comparison of big leaf versus sun/shade models for the C-14 tower at Manaus I. Canopy photosynthesis

2006 ◽  
Vol 36 (1) ◽  
pp. 69-82 ◽  
Author(s):  
Lina Mercado ◽  
Jon Lloyd ◽  
Fiona Carswell ◽  
Yadvinder Malhi ◽  
Patrick Meir ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Goodness Of Fit ◽  
Photosynthetic Parameters ◽  
The Sun ◽  
Canopy Photosynthesis ◽  
Diffuse Fraction ◽  
Sun And Shade ◽  
Residual Response ◽  
Big Leaf Model ◽  
Shade Leaves

In this study, we concentrate on modelling gross primary productivity using two simple approaches to simulate canopy photosynthesis: "big leaf" and "sun/shade" models. Two approaches for calibration are used: scaling up of canopy photosynthetic parameters from the leaf to the canopy level and fitting canopy biochemistry to eddy covariance fluxes. Validation of the models is achieved by using eddy covariance data from the LBA site C14. Comparing the performance of both models we conclude that numerically (in terms of goodness of fit) and qualitatively, (in terms of residual response to different environmental variables) sun/shade does a better job. Compared to the sun/shade model, the big leaf model shows a lower goodness of fit and fails to respond to variations in the diffuse fraction, also having skewed responses to temperature and VPD. The separate treatment of sun and shade leaves in combination with the separation of the incoming light into direct beam and diffuse make sun/shade a strong modelling tool that catches more of the observed variability in canopy fluxes as measured by eddy covariance. In conclusion, the sun/shade approach is a relatively simple and effective tool for modelling photosynthetic carbon uptake that could be easily included in many terrestrial carbon models.

scholarly journals Seasonal Variation of Tannin and Nutrient in Aegiceras corniculatum Leaves in Zhangjiang Mangrove Ecosystem

2015 ◽  
Vol 9 (1) ◽  
pp. 143-148
Author(s):  
Minshen Huang ◽  
Lihua Zhang ◽  
Shudong Wei ◽  
Qi Zeng ◽  
Haichao Zhou ◽  
...  
Keyword(s):  
Condensed Tannins ◽  
Insect Pests ◽  
Mangrove Ecosystem ◽  
Plant Diseases ◽  
The Sun ◽  
Aegiceras Corniculatum ◽  
Significant Difference ◽  
Sun And Shade ◽  
Shade Leaves ◽  
Sun Leaves

Seasonal dynamics of total phenolics (TP), extractable condensed tannins (ECT), protein-bound condensed tannins (PBCT), fiber-bound condensed tannins (FBCT), total condensed tannins (TCT) and nitrogen contents in sun and shade leaves of Aegiceras corniculatum were studied in the Zhangjiang Estuary, Fujian Province, China. The contents of TP, ECT and TCT in the sun leaves were significantly higher than those in the shade leaves through the season. The N content in sun leaves was higher than that in shade leaves in the autumn, while it was lower in the summer, and there was no significant difference in the winter and spring. With the respect to the P through the year, P content in the sun leaves was different between seasons, with the highest in winter and the lowest in summer. In addition, the TP:N and ECT:N ratios in sun leaves were significantly higher than those in shade leaves except in autumn. High tannin levels and TP:N and ECT:N ratios in the sun leaves not only can reduce oxidative stress, but also improve the ability of resisting plant diseases and insect pests.

scholarly journals I. On the causes and ecological significance of stomatal frequency, with special reference to the woodland flora

1928 ◽  
Vol 216 (431-439) ◽  
pp. 1-65 ◽  
Keyword(s):  
Comparative Anatomy ◽  
The Sun ◽  
Ecological Significance ◽  
Apparent Discrepancy ◽  
Stomatal Frequency ◽  
Sun And Shade Leaves ◽  
Sun And Shade ◽  
Numerical Variation ◽  
Shade Leaves ◽  
Sun Leaves

Though numerous investigators have recorded observations on the number of stomata present in various species, comparatively little is known respecting the causes of their numerical variation. Studies on the “sun” and “shade” leaves of woodland plants brought to light the striking differences which the numerical frequency of stomata may exhibit in leaves of the same species when growing in different environments and even in different leaves of the same individual. Various hypotheses have been put forward to explain the larger number of stomata in sun-leaves. These will be considered later, but we may note here the apparent discrepancy with the observations of Ziegeler that the leaves of the more xerophytic Carices possess fewer stomata than the leaves of those species characteristic of damper habitats. Spitzer obtained similar results from an examination of the Grasses and Adamson appears to have arrived at a similar conclusion with regard to the various species of Veronica studied by him (“Comparative anatomy of the leaves of certain species of Veronica,” Veronica " ‘Linn. Soc. Jour., Bot.,’ vol. XL, pp. 247-274, 1912).

scholarly journals Does selective logging affect the leaf structure of a late successional species?

Rodriguésia ◽  
2012 ◽  
Vol 63 (2) ◽  
pp. 419-427 ◽  
Author(s):  
Guilherme Rodrigues Rabelo ◽  
Denise Espellet Klein ◽  
Maura Da Cunha
Keyword(s):  
Leaf Area ◽  
Structural Characteristics ◽  
Selective Logging ◽  
Leaf Structure ◽  
The Sun ◽  
Seasonally Dry ◽  
Sun And Shade Leaves ◽  
Sun And Shade ◽  
Shade Leaves ◽  
Sun Leaves

The anatomical characteristics of both sun and shade leaves of Alseis pickelii were investigated in order to evaluate the consequences of selective logging (in seasonally dry Atlantic Forest) on the leaf structure of this species. Fully expanded sun and shade leaves were collected in two distinct stands of tabuleiro forest; a stand of recently logged forest and an unlogged stand. Only leaves from the unlogged stand revealed significantly different magnitudes of response to light regimes, producing leaves with structural characteristics associated with different levels of irradiance. The sun leaves from this stand had a thicker adaxial surface, mesophyll, palisade and spongy parenchyma, a secondary cell wall of fibers and a lower leaf area compared with the shade leaves. However, in the logged stand, the leaf cuticles of sun and shade leaves showed no significant differences, although the leaf area of the sun leaves was higher than the shade leaves. According to these data, we concluded that the unlogged stand produced typical "sun" and "shade" leaves. In contrast, leaves from the logged stand showed a lower variation of types, where neither typical "sun" nor typical "shade" leaves were produced, suggesting lower leaf plasticity of this late successional tree in this area.

scholarly journals Physiological aspects of sun and shade leaves of Lithraea molleoides (Vell.) Engl. (Anacardiaceae)

2007 ◽  
Vol 50 (1) ◽  
pp. 91-99 ◽  
Author(s):  
Jaqueline Dias ◽  
José Antonio Pimenta ◽  
Moacyr Eurípedes Medri ◽  
Maria Regina Torres Boeger ◽  
Claudinei Toledo de Freitas
Keyword(s):  
Stomatal Conductance ◽  
Nutrient Concentration ◽  
Physiological Parameter ◽  
The Sun ◽  
Chlorophyll B ◽  
Sun And Shade Leaves ◽  
Lower Light ◽  
Sun And Shade ◽  
Shade Leaves ◽  
Sun Leaves

The aim of this work was to compare the physiological parameters of sun and shade leaves of a specimen of L. molleoides. The higher-positional leaves, classified as sun leaves, presented similar photosynthetic rate, lower chlorophyill contents (a, b and total), same a chlorophyll /b chlrorophyll rate, lower transpiratory rate, same stomatal conductance and intercellular concentration of CO2 as the lower-positional leaves, classified as shade leaves. Nutrient concentration, except for Ca and Mg, was the same for both sun and shade leaves.The physiological parameter responses indicated that although receiving lower light intensity, the shade leaves had the same capacity to grow and develop as the sun leaves.

scholarly journals Do Camels (Camelus dromedarius) Need Shaded Areas? A Case Study of the Camel Market in Doha

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 480
Author(s):  
Martina Zappaterra ◽  
Laura Menchetti ◽  
Leonardo Nanni Costa ◽  
Barbara Padalino
Keyword(s):  
Ad Hoc ◽  
The Sun ◽  
Chi Square ◽  
Chi Square Test ◽  
Variable Space ◽  
Group 2 ◽  
Sun And Shade ◽  
Poor Welfare ◽  
Group 1

This study aimed at documenting whether dromedary camels have a preference for shade and how their behavior would change depending on the presence of shade and variable space allowance. A total of 421 animals kept in 76 pens (66 with shelter (Group 1), and 10 without shelter (Group 2)) at the camel market in Doha (Qatar) were recorded for 1 min around 11:00 a.m. when the temperature was above 40 °C. The number of animals in the sun and shade and their behaviors were analyzed using an ad libitum sampling method and an ad hoc ethogram. The results of a chi-square test indicated that camels in Group 1 had a clear preference for shade (p < 0.001). The majority of Group 1 camels were indeed observed in the shade (312/421; 74.11%). These camels spent more time in recumbency and ruminating, while standing, walking, and self-grooming were more commonly expressed by the camels in the sun (p < 0.001). Moreover, locomotory stereotypic behaviors (i.e., pacing) increased as space allowance decreased (p = 0.002). Based on the findings of this pilot study, camels demonstrated a preference for shade; shade seemed to promote positive welfare, while overcrowding seemed to trigger stereotypy and poor welfare. Overall, our preliminary results are novel and provide evidence that shaded areas are of paramount importance for camel welfare. Further research, involving designed studies at multiple locations is needed to confirm these results.

Photosynthesis Response of Sunlit and Shade Pepper (Capsicum annuum) Leaves at Different Positions in the Canopy Under Two Water Regimes

1994 ◽  
Vol 21 (3) ◽  
pp. 377 ◽  
Author(s):  
A Alvino ◽  
M Centritto ◽  
FD Lorenzi
Keyword(s):  
Water Potential ◽  
Capsicum Annuum ◽  
Leaf Water Potential ◽  
Co2 Exchange ◽  
Leaf Water ◽  
Predawn Leaf Water Potential ◽  
Water Regimes ◽  
Water Potentials ◽  
Sun And Shade ◽  
Shade Leaves

Pepper (Capsicum annuum L.) plants were grown in 1 m2 lysimeters under two different water regimes in order to investigate differences in the spatial arrangements of the leaves and to relate this to daily assimilation rates of leaves of the canopy. The control regime (well-watered (W) treatment) was irrigated whenever the accumulated 'A' pan evaporation reached 4 cm, whereas the water-stressed (S) treatment was watered whenever the predawn leaf water potential fell below -1 MPa. During the growing cycle, equal numbers of sun and shade leaves were chosen from the apical, middle and basal parts of the canopy, corresponding to groups of leaves of increasing age. The CO2 exchange rate (CER) was measured at 0830, 1230 and 1530 hours on 8 days along the crop cycle, on leaves in their natural inclination and orientation. Leaf water potentials were measured on apical leaves before dawn and concurrently with gas exchange measurements. Control plants maintained predawn leaf water potential at -0.3 MPa, but S plants reached values lower than -1.2 MPa. Midday leaf water potentials were about twice as low in the S plants as in the controls. Water stress reduced LA1 during the period of crop growth, and dry matter production at harvest. Stressed apical leaves appeared to reduce stress by changing their inclination. They were paraheliotropic around midday and diaheliotropic at 0830 and 1530 hours. The CER values of the S treatment were significantly lower than those of the W treatment in apical and middle leaves, whereas the CER of basal leaves did not differ in either treatments. In the S treatment, reduction in the CER values of sunlit apical leaves was more evident in the afternoon than at midday or early in the morning, whereas basal leaves were less affected by water than basal stress leaves if sunlit, and negligibly in shaded conditions.

scholarly journals Photosynthetic induction and activity of enzymes related to carbon metabolism: insights into the varying net photosynthesis rates of coffee sun and shade leaves

2013 ◽  
Vol 25 (1) ◽  
pp. 62-69 ◽  
Author(s):  
Samuel Cordeiro Vitor Martins ◽  
Kelly Coutinho Detmann ◽  
Josimar Vieira dos Reis ◽  
Lucas Felisberto Pereira ◽  
Lílian Maria Vincis Pereira Sanglard ◽  
...  
Keyword(s):  
Carbon Metabolism ◽  
Net Photosynthesis ◽  
Photosynthetic Induction ◽  
Sun And Shade Leaves ◽  
Activity Of Enzymes ◽  
Sun And Shade ◽  
Shade Leaves

scholarly journals Morphological and anatomical aspects of the leaves of Rhizophora mangle L. (Rhizophoraceae) under different lighting conditions / Aspectos morfológicos e anatômicos das folhas de Rhizophora mangle L. (Rhizophoraceae) sob diferentes condições de luz

2016 ◽  
Vol 12 (2) ◽  
pp. 74
Author(s):  
Camilla Reis Augusto da Silva ◽  
Marcelo Dos Santos Silva ◽  
Léa Maria Dos Santos Lopes Ferreira ◽  
Kelly Regina Batista Leite ◽  
Lazaro Benedito da Silva
Keyword(s):  
Stomatal Density ◽  
Rhizophora Mangle ◽  
Palisade Parenchyma ◽  
Abaxial Epidermis ◽  
Lighting Conditions ◽  
Ocular Micrometer ◽  
Significant Difference ◽  
Sun And Shade ◽  
Shade Leaves ◽  
Sun Leaves

The basis of differentiation between sun and shade leaves is related to different light intensities. In order to understand the adaptability of the leaves of Rhizophora mangle L., associated with different lighting conditions, leaves were collected from the upper peripheral six individuals (sun leaves) and the lower region of the same internal (shade leaves). The variables analyzed leaf thickness, palisade parenchyma, adaxial and abaxial epidermis, adaxial and abaxial cuticle, stomatal density and index. Measurements were made ??on microscope equipped with ocular micrometer. Sun leaves were lower and with more xeromorphic characteristics, such as increased thickness of the cuticle and the adaxial and abaxial epidermis. The palisade parenchyma and limbus showed up thicker than shade leaves, with no significant difference between the cuticle of the abaxial surface. It was also observed a higher frequency of stomata per mm², an average of 70/mm², while shade leaves showed 47/mm², with no differences between length and width. Differences between the sun leaves and shade leaves indicate adaptive capacity of this species to remain active at different light conditions.

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