The effect of light environment, leaf area, and stored carbohydrates on inflorescence production by a rain forest understory palm

Oecologia ◽  
1997 ◽  
Vol 111 (1) ◽  
pp. 36-44 ◽  
Author(s):  
Saul A. Cunningham
Keyword(s):  
Leaf Area ◽  
Rain Forest ◽  
Light Environment ◽  
Forest Understory ◽  
Effect Of Light

scholarly journals Coupled carbon-water exchange of the Amazon rain forest, I. Model description, parameterization and sensitivity analysis

2005 ◽  
Vol 2 (2) ◽  
pp. 333-397 ◽  
Author(s):  
E. Simon ◽  
F. X. Meixner ◽  
L. Ganzeveld ◽  
J. Kesselmeier
Keyword(s):  
Stomatal Conductance ◽  
Leaf Area ◽  
Rain Forest ◽  
Canopy Structure ◽  
Leaf Nitrogen ◽  
Optical Parameters ◽  
Amazon Rain Forest ◽  
Leaf Level ◽  
Net Assimilation ◽  
Parameter Values

Abstract. Detailed one-dimensional multilayer biosphere-atmosphere models, also referred to as CANVEG models, are used for more than a decade to describe coupled water-carbon exchange between the terrestrial vegetation and the lower atmosphere. Within the present study, a modified CANVEG scheme is described. A generic parameterization and characterization of biophysical properties of Amazon rain forest canopies is inferred using available field measurements of canopy structure, in-canopy profiles of horizontal wind speed and radiation, canopy albedo, soil heat flux and soil respiration, photosynthetic capacity and leaf nitrogen as well as leaf level enclosure measurements made on sunlit and shaded branches of several Amazonian tree species during the wet and dry season. The sensitivity of calculated canopy energy and CO2 fluxes to the uncertainty of individual parameter values is assessed. In the companion paper, the predicted seasonal exchange of energy, CO2, ozone and isoprene is compared to observations. A bi-modal distribution of leaf area density with a total leaf area index of 6 is inferred from several observations in Amazonia. Predicted light attenuation within the canopy agrees reasonably well with observations made at different field sites. A comparison of predicted and observed canopy albedo shows a high model sensitivity to the leaf optical parameters for near-infrared short-wave radiation (NIR). The predictions agree much better with observations when the leaf reflectance and transmission coefficients for NIR are reduced by 25–40%. Available vertical distributions of photosynthetic capacity and leaf nitrogen concentration suggest a low but significant light acclimation of the rain forest canopy that scales nearly linearly with accumulated leaf area. Evaluation of the biochemical leaf model, using the enclosure measurements, showed that recommended parameter values describing the photosynthetic light response, have to be optimized. Otherwise, predicted net assimilation is overestimated by 30–50%. Two stomatal models have been tested, which apply a well established semi-empirical relationship between stomatal conductance and net assimilation. Both models differ in the way they describe the influence of humidity on stomatal response. However, they show a very similar performance within the range of observed environmental conditions. The agreement between predicted and observed stomatal conductance rates is reasonable. In general, the leaf level data suggests seasonal physiological changes, which can be reproduced reasonably well by assuming increased stomatal conductance rates during the wet season, and decreased assimilation rates during the dry season. The sensitivity of the predicted canopy fluxes of energy and CO2 to the parameterization of canopy structure, the leaf optical parameters, and the scaling of photosynthetic parameters is relatively low (1–12%), with respect to parameter uncertainty. In contrast, modifying leaf model parameters within their uncertainty range results in much larger changes of the predicted canopy net fluxes (5–35%).

scholarly journals Coupled carbon-water exchange of the Amazon rain forest, I. Model description, parameterization and sensitivity analysis

2005 ◽  
Vol 2 (3) ◽  
pp. 231-253 ◽  
Author(s):  
E. Simon ◽  
F. X. Meixner ◽  
L. Ganzeveld ◽  
J. Kesselmeier
Keyword(s):  
Stomatal Conductance ◽  
Leaf Area ◽  
Rain Forest ◽  
Canopy Structure ◽  
Leaf Nitrogen ◽  
Optical Parameters ◽  
Amazon Rain Forest ◽  
Leaf Level ◽  
Net Assimilation ◽  
Parameter Values

Abstract. Detailed one-dimensional multilayer biosphere-atmosphere models, also referred to as CANVEG models, are used for more than a decade to describe coupled water-carbon exchange between the terrestrial vegetation and the lower atmosphere. Within the present study, a modified CANVEG scheme is described. A generic parameterization and characterization of biophysical properties of Amazon rain forest canopies is inferred using available field measurements of canopy structure, in-canopy profiles of horizontal wind speed and radiation, canopy albedo, soil heat flux and soil respiration, photosynthetic capacity and leaf nitrogen as well as leaf level enclosure measurements made on sunlit and shaded branches of several Amazonian tree species during the wet and dry season. The sensitivity of calculated canopy energy and CO2 fluxes to the uncertainty of individual parameter values is assessed. In the companion paper, the predicted seasonal exchange of energy, CO2, ozone and isoprene is compared to observations. A bi-modal distribution of leaf area density with a total leaf area index of 6 is inferred from several observations in Amazonia. Predicted light attenuation within the canopy agrees reasonably well with observations made at different field sites. A comparison of predicted and observed canopy albedo shows a high model sensitivity to the leaf optical parameters for near-infrared short-wave radiation (NIR). The predictions agree much better with observations when the leaf reflectance and transmission coefficients for NIR are reduced by 25–40%. Available vertical distributions of photosynthetic capacity and leaf nitrogen concentration suggest a low but significant light acclimation of the rain forest canopy that scales nearly linearly with accumulated leaf area. Evaluation of the biochemical leaf model, using the enclosure measurements, showed that recommended parameter values describing the photosynthetic light response, have to be optimized. Otherwise, predicted net assimilation is overestimated by 30–50%. Two stomatal models have been tested, which apply a well established semi-empirical relationship between stomatal conductance and net assimilation. Both models differ in the way they describe the influence of humidity on stomatal response. However, they show a very similar performance within the range of observed environmental conditions. The agreement between predicted and observed stomatal conductance rates is reasonable. In general, the leaf level data suggests seasonal physiological changes, which can be reproduced reasonably well by assuming increased stomatal conductance rates during the wet season, and decreased assimilation rates during the dry season. The sensitivity of the predicted canopy fluxes of energy and CO2 to the parameterization of canopy structure, the leaf optical parameters, and the scaling of photosynthetic parameters is relatively low (1–12%), with respect to parameter uncertainty. In contrast, modifying leaf model parameters within their uncertainty range results in much larger changes of the predicted canopy net fluxes (5–35%).

Upper canopy pollinators of Eucryphia cordifolia Cav., a tree of South American temperate rain forest

2016 ◽  
Vol 4 (9) ◽  
pp. 1 ◽  
Author(s):  
Cecilia Smith-Ramírez ◽  
Paula Martínez ◽  
Iván Díaz ◽  
Marcelo Galaz ◽  
Juan J. Armesto
Keyword(s):  
Rain Forest ◽  
Temperate Forest ◽  
Forest Canopy ◽  
Forest Understory ◽  
South American ◽  
Ecological Processes ◽  
Flower Visitors ◽  
Temperate Rain Forest ◽  
Tall Tree ◽  
Pollinator Assemblage

Ecological processes in the upper canopy of temperate forests have been seldom studied because of the limited accessibility. Here, we present the results of the first survey of the pollinator assemblage and the frequency of insect visits to flowers in the upper branches of ulmo, Eucryphia cordifolia Cav., an emergent 30-40 m-tall tree in rainforests of Chiloé Island, Chile. We compared these findings with a survey of flower visitors restricted to lower branches of E. cordifolia 1- in the forest understory, 2- in lower branches in an agroforestry area. We found 10 species of pollinators in canopy, and eight, 12 and 15 species in understory, depending of tree locations. The main pollinators of E. cordifolia in the upper canopy differed significantly from the pollinator assemblage recorded in lower tree branches. We conclude that the pollinator assemblages of the temperate forest canopy and interior are still unknown.

scholarly journals Amazon forest carbon dynamics predicted by profiles of canopy leaf area and light environment

2012 ◽  
Vol 15 (12) ◽  
pp. 1406-1414 ◽  
Author(s):  
Scott C. Stark ◽  
Veronika Leitold ◽  
Jin L. Wu ◽  
Maria O. Hunter ◽  
Carolina V. de Castilho ◽  
...  
Keyword(s):  
Leaf Area ◽  
Carbon Dynamics ◽  
Forest Carbon ◽  
Light Environment ◽  
Amazon Forest

Morphology of young sugarcane stalks produced at different stages of crop development

2008 ◽  
Vol 59 (2) ◽  
pp. 149 ◽  
Author(s):  
B. Salter ◽  
G. D. Bonnett ◽  
R. J. Lawn
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Leaf Length ◽  
Light Environment ◽  
Sucrose Content ◽  
Leaf Lamina ◽  
Crop Development ◽  
Breadth Ratio ◽  
Morphological Differences ◽  
Plant Crop

Sugarcane suckers are tillers that appear late in crop development. They dilute the sucrose content of the harvested cane at the mill, reducing grower profitability. Suckers appear to have different morphology from other sugarcane stalks. Experiments were established to quantify some of these morphological differences, to determine whether these differences were conserved across a vegetatively propagated generation, and to investigate the influence of the mature stalk to which the sucker is attached on sucker morphology. Experiments were established in northern Queensland, Australia, using cvv. Q117, Q138, and Q152 to compare suckers with young primary stalks in a plant crop and/or young ratoon stalks. Leaf lamina length, breadth, area, height to last fully expanded leaf, internode diameter, and growth measurements were taken. Suckers had broader leaves, resulting in a smaller leaf length/breadth ratio, longer leaf sheaths, and lower specific leaf area at least for the first 3 leaves. Sucker stalks were thicker than normal stalks. Sucker growth was highly variable, but some were able to outgrow young primary stalks in a plant crop. When mature stalks, to which suckers were attached, were removed, the leaves produced by suckers were more similar to leaves on normal stalks with larger length/breadth ratio. The morphological differences were not carried over into plants arising from the buds on suckers. Although the reasons for these morphological differences are unknown, it is likely that the transfer of some factor(s) from the stalks to which suckers are attached, and/or an altered light environment within the canopy, may contribute to the morphology of sucker shoots.

scholarly journals Shading, Growth, and Dry-matter Partitioning of Cocoyam [Xanthosoma sagittifolium (L.) Schott]

1991 ◽  
Vol 116 (6) ◽  
pp. 1117-1121 ◽  
Author(s):  
Hector R. Valenzuela ◽  
Stephen K. O'Hair ◽  
Bruce Schaffer
Keyword(s):  
Leaf Area ◽  
Linear Equations ◽  
Dry Weight ◽  
Leaf Lamina ◽  
Dry Matter Partitioning ◽  
Area Index ◽  
Xanthosoma Sagittifolium ◽  
Leaf Density ◽  
Net Assimilation ◽  
Effect Of Light

Cocoyam was grown in 100%, 50%, or 30% daylight to determine the effect of light intensity on growth characteristics at various stages of plant development. Beginning ≈ 2 months after planting, growth was monitored at three or four monthly intervals. Plants grown in shade had more petiole and leaf lamina growth and extension, as well as increased top: corm plus cormel ratio (dry-weight basis), than plants grown in 100% daylight. Shade-grown plants had a higher leaf area index and specific leaf area than sun-grown plants. Sun-grown plants had a higher net assimilation rate and specific leaf density than shade-grown plants. Linear equations were developed to predict lamina area through measurements of leaf lamina width and length, petiole length, and lamina dry weight.

The effect of light environment during tillage on the recruitment of various summer annuals

Weed Science ◽  
1998 ◽  
Vol 46 (2) ◽  
pp. 214-216 ◽  
Author(s):  
Robert S. Gallagher ◽  
John Cardina
Keyword(s):  
Weed Management ◽  
Light Environment ◽  
Light Conditions ◽  
Agricultural Systems ◽  
Giant Foxtail ◽  
Viable Approach ◽  
High Degree ◽  
Weed Emergence ◽  
Tillage Operations ◽  
Effect Of Light

Weed seeds can require an exposure to light for induction of germination. Conducting tillage operations at night and thus preventing the photoinduction of germination has been proposed as a means to reduce weed emergence in agricultural systems. This research was conducted to evaluate night tillage as a weed management option and to determine which tillage operations have the greatest effect on light-mediated recruitment. Weed emergence was evaluated after conducting factorial combinations of day and night moldboard plowing and disking in the springtime from 1992 through 1995. The light environment during disking generally had a slightly greater effect on emergence than the light environment during plowing. Emergence of pigweed species and giant foxtail was, at most, 30 to 55% higher following day vs. night disking. Emergence of other weeds was not affected by the light environment during tillage. We conclude that night tillage may not be a viable approach to weed management due to insufficient reductions in weed emergence associated with night tillage and the high degree of variability in the recruitment response to light conditions during tillage.

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