On the Role of Photosynthetic Responses in Constraining the Habitat Distribution of Rainforest Plants

1988 ◽  
Vol 15 (2) ◽  
pp. 343 ◽  
Author(s):  
CB Field
Keyword(s):  
Dark Respiration ◽  
Complex Function ◽  
Light Availability ◽  
Leaf Nitrogen ◽  
Photosynthetic Characteristics ◽  
Light Environment ◽  
Total Carbon ◽  
Carbon Gain ◽  
Canopy Architecture ◽  
Nitrogen Levels

Two rainforest species that differ in the range of light environments encountered by an individual provide a model system for illustrating implications of diurnal variation and spatial heterogeneity of the light environment within single canopies. The two species are similar in the acclimation of leaf-level photosynthetic characteristics to the leaf's past light environment, but are distinguished by the limited ability of the high-light species to decrease dark respiration in response to growth under shade. Over 24 h, total carbon gain from a leaf increases with increasing light, but may increase or decrease with increasing nitrogen. Intermediate nitrogen levels and photosynthetic capacities yield maximum daily carbon gain in only a narrow range of light environments. The ratio of daily photosynthesis to leaf nitrogen is a complex function of nitrogen, photosynthetic characteristics, and light availability in a microsite. Nitrogen levels in real leaves may be close to the optima, but leaf nitrogen levels are clumped relative to the optima. Daily carbon gain from a canopy of fixed total nitrogen tends to increase as the leaf area of the canopy decreases, a trend caused by two factors. First, photosynthetic capacity is a nearly linear function of leaf nitrogen up to the highest nitrogen levels observed in nature. Second, only leaves with nitrogen levels above a substantial threshold are competent to generate positive rates of net photosynthesis. Differences between the species in canopy architecture and leaf duration have counteracting effects on long-term nitrogen-use efficiency.

Photosynthesis and respiration decline with light intensity in dominant and suppressed Eucalyptus globulus canopies

2008 ◽  
Vol 35 (6) ◽  
pp. 439 ◽  
Author(s):  
A. P. O'Grady ◽  
D. Worledge ◽  
A. Wilkinson ◽  
M. Battaglia
Keyword(s):  
Eucalyptus Globulus ◽  
Dark Respiration ◽  
Light Availability ◽  
Structural Complexity ◽  
Leaf Nitrogen ◽  
Leaf Nitrogen Content ◽  
Area Index ◽  
Respiration Rates ◽  
Leaf Dark Respiration ◽  
Photosynthesis And Respiration

Within canopy gradients in light-saturated photosynthesis (Amax), foliar nitrogen ([N]area) and leaf dark respiration (R15) were studied in the canopies of dominant and suppressed trees within an even-aged (4-year-old) Eucalyptus globulus (Labill) stand in southern Tasmania. Despite being an even-aged stand growing in a relatively uniform environment with respect to nutrient and water availability, the stand exhibited considerable structural complexity. Diameter at 1.3 m ranged between 3 cm and 21 cm, trees average 12 m height and stand leaf area index was ~6 m2 m–2 leading to strong gradients in light availability. We were interested in understanding the processes governing canopy production in trees of contrasting dominance classes. Vertical gradients in photosynthesis and foliar respiration were studied within the canopies of dominant and suppressed trees during 2006 and 2007. Amax varied from ~18 μmol m–2 s–1 in the upper canopy to 3 μmol m–2 s–1 at lower canopy positions. On average, Amax were higher in the dominant trees than in the suppressed trees. However, at any given height, Amax were similar in suppressed and dominant trees and were strongly related to leaf nitrogen content. Dark respiration varied from ~1.4 μmol m–2 s–1 in the upper canopy to 0.2 μmol m–2 s–1 in the lower canopy positions. In contrast to the patterns for Amax, dark respiration rates in the suppressed trees were higher than dominant trees at similar canopy positions. Respiration rates were also strongly related to [N]area and to Amax.

scholarly journals Seasonal courses of photosynthetic parameters in sun- and shade-acclimated spruce shoots

Beskydy ◽  
2017 ◽  
Vol 10 (1-2) ◽  
pp. 49-56 ◽  
Author(s):  
Otmar Urban ◽  
Petr Holub ◽  
Karel Klem
Keyword(s):  
Photosynthetic Capacity ◽  
Dark Respiration ◽  
Carbon Assimilation ◽  
Growing Season ◽  
Early Spring ◽  
Total Carbon ◽  
Carbon Gain ◽  
Carbon Uptake ◽  
Photosynthetic Parameters ◽  
Sun And Shade

Exponential attenuation of light intensity passing through forest canopies leads to the formation of sun- and shade-acclimated leaves contributing to overall canopy carbon gain. Using a gas-exchange technique, seasonal changes in photosynthetic parameters were investigated in situ to test the hypothesis that the relative contributions of sun- and shade-acclimated Norway spruce shoots to total carbon gain vary during the growing season and that the contribution of sun-acclimated shoots to total carbon uptake may be reduced during the hot and dry summer season. In agreement with the tested hypothesis, we found reduced photosynthetic capacity as well as reduced light-use efficiency for carbon assimilation in sun-acclimated shoots during summer months while these remained almost unchanged in shade-acclimated shoots. Reduction of photosynthetic capacity was primarily associated with reduced stomatal conductance. On the other hand, seasonal courses of mitochondrial dark respiration, quantum efficiency of photosynthetic reactions, and compensation irradiance were primarily driven by changes in temperature. Accordingly, the photosynthetic characteristics of sun- and shade-acclimated shoots tended to converge in early spring and late autumn when temperature was low. Such seasonal dynamics result in an increased contribution of shade-acclimated shoots to total carbon uptake at the beginning and end of the growing season as well as during hot and dry summer periods.

scholarly journals Photosynthetic and Morphological Acclimation to High and Low Light Environments in Petasites japonicus subsp. giganteus

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1365 ◽  
Author(s):  
Ray Deguchi ◽  
Kohei Koyama
Keyword(s):  
Respiration Rate ◽  
Photosynthetic Rate ◽  
Dark Respiration ◽  
Light Environment ◽  
Carbon Gain ◽  
Dark Respiration Rate ◽  
Sun And Shade Leaves ◽  
Sun And Shade ◽  
Shade Leaves ◽  
Petasites Japonicus

Within each species, leaf traits such as light-saturated photosynthetic rate or dark respiration rate acclimate to local light environment. Comparing only static physiological traits, however, may not be sufficient to evaluate the effects of such acclimation in the shade because the light environment changes diurnally. We investigated leaf photosynthetic and morphological acclimation for a perennial herb, butterbur (Petasites japonicus (Siebold et Zucc.) Maxim. subsp. giganteus (G.Nicholson) Kitam.) (Asteraceae), in both a well-lit clearing and a shaded understory of a temperate forest. Diurnal changes in light intensity incident on the leaves were also measured on a sunny day and an overcast day. Leaves in the clearing were more folded and upright, whereas leaves in the understory were flatter. Leaf mass per area (LMA) was approximately twofold higher in the clearing than in the understory, while light-saturated photosynthetic rate and dark respiration rate per unit mass of leaf were similar between the sites. Consequently, both light-saturated photosynthetic rate and dark respiration rate per unit area of leaf were approximately twofold higher in the clearing than in the understory, consistent with previous studies on different species. Using this experimental dataset, we performed a simulation in which sun and shade leaves were hypothetically exchanged to investigate whether such plasticity increased carbon gain at each local environment. As expected, in the clearing, the locally acclimated sun leaves gained more carbon than the hypothetically transferred shade leaves. By contrast, in the understory, the daily net carbon gain was similar between the simulated sun and shade leaves on the sunny day due to the frequent sunflecks. Lower LMA and lower photosynthetic capacity in the understory reduced leaf construction cost per area rather than maximizing net daily carbon gain. These results indicate that information on static photosynthetic parameters may not be sufficient to evaluate shade acclimation in forest understories.

Seasonal pattern of leaf production and its effects on assimilation in giant summer-green herbs in deciduous forests in northern Japan

2006 ◽  
Vol 84 (1) ◽  
pp. 87-98 ◽  
Author(s):  
Tomokazu Tani ◽  
Gaku Kudo
Keyword(s):  
Dark Respiration ◽  
Seasonal Pattern ◽  
Light Availability ◽  
High Irradiance ◽  
Tree Canopy ◽  
Deciduous Forests ◽  
Carbon Gain ◽  
Canopy Closure ◽  
Leaf Production ◽  
Short Period

Understory vegetation of northern deciduous forests in far eastern Asia is characterized by giant summer-green herbs. We examined the patterns of height growth, leaf accumulation, photosynthetic characteristics, daily net assimilation, and dry matter allocation within aboveground parts of six giant summer-green herbs with reference to light conditions in deciduous forests. Plant height, leaf number, and total leaf area per plant increased with progressing tree-canopy closure in five species ( Cacalia hastata L. subsp. orientalis Kitam., Cirsium kamtschaticum Ledeb., Filipendula kamtschatica (Pall.) Maxim. f. kamtschatica, Senecio cannabifolius Less., and Urtica platyphylla Wedd.) that had continuous leaf production throughout the growing season, whereas one species ( Veratrum album L. subsp. oxysepalum Hulten) with early leaf production, completed leaf production mostly before the beginning of tree-canopy closure. Maximum photosynthetic and dark respiration rates decreased seasonally in all species. Species with continuous leaf emergence accumulated leaves acclimatized to shade conditions, which offset the decreasing photosynthesis of individual leaves with progressing tree-canopy closure, resulting in stable carbon gain even under decreasing light availability. In contrast, V. album assimilated vigorously during the short period of high irradiance before tree-canopy closure, and decreased its assimilation rate continuously thereafter.

scholarly journals Light environment drives evolution of color vision genes in butterflies and moths

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yash Sondhi ◽  
Emily A. Ellis ◽  
Seth M. Bybee ◽  
Jamie C. Theobald ◽  
Akito Y. Kawahara
Keyword(s):  
Amino Acids ◽  
Color Vision ◽  
Light Availability ◽  
High Light ◽  
Light Environment ◽  
Evolution Rate ◽  
Animal Evolution ◽  
Light Sensing ◽  
Rates Of Evolution ◽  
Gains And Losses

AbstractOpsins, combined with a chromophore, are the primary light-sensing molecules in animals and are crucial for color vision. Throughout animal evolution, duplications and losses of opsin proteins are common, but it is unclear what is driving these gains and losses. Light availability is implicated, and dim environments are often associated with low opsin diversity and loss. Correlations between high opsin diversity and bright environments, however, are tenuous. To test if increased light availability is associated with opsin diversification, we examined diel niche and identified opsins using transcriptomes and genomes of 175 butterflies and moths (Lepidoptera). We found 14 independent opsin duplications associated with bright environments. Estimating their rates of evolution revealed that opsins from diurnal taxa evolve faster—at least 13 amino acids were identified with higher dN/dS rates, with a subset close enough to the chromophore to tune the opsin. These results demonstrate that high light availability increases opsin diversity and evolution rate in Lepidoptera.

scholarly journals Phenology as a strategy for carbon optimality: a global model

2014 ◽  
Vol 11 (3) ◽  
pp. 763-778 ◽  
Author(s):  
S. Caldararu ◽  
D. W. Purves ◽  
P. I. Palmer
Keyword(s):  
Leaf Growth ◽  
Mechanistic Model ◽  
Leaf Age ◽  
Light Availability ◽  
Carbon Assimilation ◽  
Carbon Gain ◽  
Area Index ◽  
Growing Season Length ◽  
Tropical Areas ◽  
Gains And Losses

Abstract. Phenology is essential to our understanding of biogeochemical cycles and the climate system. We develop a global mechanistic model of leaf phenology based on the hypothesis that phenology is a strategy for optimal carbon gain at the canopy level so that trees adjust leaf gains and losses in response to environmental factors such as light, temperature and soil moisture, to achieve maximum carbon assimilation. We fit this model to five years of satellite observations of leaf area index (LAI) using a Bayesian fitting algorithm. We show that our model is able to reproduce phenological patterns for all vegetation types and use it to explore variations in growing season length and the climate factors that limit leaf growth for different biomes. Phenology in wet tropical areas is limited by leaf age physiological constraints while at higher latitude leaf seasonality is limited by low temperature and light availability. Leaf growth in grassland regions is limited by water availability but often in combination with other factors. This model will advance the current understanding of phenology for ecosystem carbon models and our ability to predict future phenological behaviour.

Repair of severe winter xylem embolism supports summer water transport and carbon gain in flagged crowns of the subalpine conifer Abies veitchii

2019 ◽  
Vol 39 (10) ◽  
pp. 1725-1735 ◽  
Author(s):  
Mayumi Y Ogasa ◽  
Haruhiko Taneda ◽  
Hiroki Ooeda ◽  
Akihiro Ohtsuka ◽  
Emiko Maruta
Keyword(s):  
Leaf Nitrogen ◽  
Carbon Gain ◽  
Late Winter ◽  
Leaf Nitrogen Content ◽  
Xylem Embolism ◽  
Coniferous Species ◽  
Abies Veitchii ◽  
Individual Level ◽  
Use Efficiency ◽  
The Individual

Abstract Xylem embolism induced by winter drought is a serious dysfunction in evergreen conifers growing at wind-exposed sites in the mountains. Some coniferous species can recover from winter embolism. The aim of this study was to determine whether wind direction influences embolism formation and/or repair dynamics on short windward and long leeward branches of asymmetrical `flagged' crowns. We analyzed the effect of branch orientation on percentage loss of xylem conductive area (PLC), leaf functional traits and the xylem:leaf area ratio for subalpine, wind-exposed flagged-crown Abies veitchii trees in the northern Yatsugatake Mountains of central Japan. In late winter, the shoot water potential was below −2.5 MPa, and the PLC exceeded 80% in 2-year-old branches, independent of branch orientation within a flagged crown. Both of these parameters almost fully recovered by summer. At branch internodes 4 years of age and older, seasonal changes in PLC were not found in either windward or leeward branches, but the PLC was higher in less leafy windward branches. The leaf nitrogen content and water-use efficiency of mature leaves were comparable between windward branches and leafy leeward branches. The ratio of xylem conductive area to total leaf area was the same for windward and leeward branches. These results indicate that the repair of winter xylem embolism allows leaf physiological functions to be maintained under sufficient leaf water supply, even on winter-wind-exposed branches. This permits substantial photosynthetic carbon gain during the following growing season on both windward and leeward branches. Thus, xylem recovery from winter embolism is a key trait for the survival of harsh winters and to support productivity on the individual level in flagged-crown A. veitchii trees.

Photosynthesis and physiological traits of evergreen broadleafed saplings during winter under different light environments in a temperate forest

2006 ◽  
Vol 84 (1) ◽  
pp. 60-69 ◽  
Author(s):  
Yoshiyuki Miyazawa ◽  
Kihachiro Kikuzawa
Keyword(s):  
Temperate Forest ◽  
Light Availability ◽  
Net Photosynthesis ◽  
Carbon Gain ◽  
Leaf Mass Per Area ◽  
Camellia Japonica ◽  
Leaf Mass ◽  
Unit Leaf ◽  
Canopy Trees ◽  
Photosynthetic Traits

Photosynthetic traits of the evergreen broadleafed species Camellia japonica L. and Quercus glauca Thunb. were continuously investigated during autumn and winter using saplings that grew in different light environments (gap, deciduous canopy understory, and evergreen canopy understory) in a temperate forest. Light-saturated rates of net photosynthesis in midwinter and spring were lower than those in autumn. Photosynthetic capacity, scaled to a common leaf temperature of 25 °C, increased or remained stable after autumn and then decreased in spring in most leaves. Photosynthetic traits per unit leaf area were different among leaves in different light environments of both Camellia and Quercus during most periods. However, photosynthetic traits per unit leaf mass did not differ among leaves in different light environments, suggesting that differences in photosynthetic traits were mainly due to different leaf mass per area among leaves. Photosynthetic rates under light availability typical in the environment were lower in winter than in autumn in leaves in the sun in a gap but were not different in leaves in the shade under evergreen canopy trees. Thus, the importance of winter carbon gain for annual carbon gain is small in leaves in a gap but is large in leaves under evergreen canopy trees.

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