Spectral composition of photosynthetically active radiation penetrating into a Norway spruce canopy: the opposite dynamics of the blue/red spectral ratio during clear and overcast days

Navrátil, Martin; Špunda, Vladimı́r; Marková, Irena; Janouš, Dalibor

doi:10.1007/s00468-007-0124-4

Cited by 41 publications

(24 citation statements)

References 54 publications

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“…However, the quality of radiation, including its spectral composition within the canopy layer, is also important as it may influence physiology and the photosynthetic apparatus (Navrátil et al 2007;Grant 1997). However, understanding whole plant photosynthesis is complicated due to the pronounced spatial PAR differences (Meir et al 2002).…”

Section: Determination Of Vegetation By Stand Ie Canopy Effectsmentioning

confidence: 99%

Canopy effects on vegetation caused by harvesting and regeneration treatments

2010

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This paper reviews the primary effects of canopy on understorey vegetation to provide insight into the management of the canopy space to benefit tree regeneration. Site conditions, like nutrient and water availability, overstorey conditions, e.g. tree species, and canopy density, are important determinants of ground vegetation. An investigation of canopy effects is concerned about how the canopy trees modify site conditions. As canopy density may be deliberately modified during regeneration treatments, the effect of canopy density on individual species in the herbaceous layer and tree regeneration is important. This autecological perspective focuses on the successional traits of species to help understand species differences in fecundity, survival, density and growth. From a synecological perspective, the importance of successional traits for the outcome of competition between species arising from differences in canopy densities is highlighted. This review shows that moderately dense canopies may favour tree regeneration over aggressive shade-intolerant graminoids or forbs. This is particularly true for shade-tolerant and intermediate shade-tolerant tree species. To better understand and utilise this phenomenon, research should try to identify and isolate different canopy effects.

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Section: Determination Of Vegetation By Stand Ie Canopy Effectsmentioning

confidence: 99%

Canopy effects on vegetation caused by harvesting and regeneration treatments

2010

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“…Therefore, transmitted diffuse radiation in the understory is characterized by reduced R/FR (≈ 0.15) and B/R (≈ 0.35) ratios compared with that above the canopy (Frankland 1986, Campbell andNorman 1998). However, Navrátil et al (2007) reported that direct solar radiation penetrating into the lower parts of coniferous canopies may have an increased B/R ratio up to 2.5, especially at low solar elevation angles (10-20°).…”

Section: Introductionmentioning

confidence: 94%

“…Plants in natural environments are exposed to incident radiation of varying photon flux density (PFD) and spectral quality (Frankland 1986, Grant 1997, Murchie and Horton 1997, over a wide range of temporal and particularly at low (10-20°) solar elevation angles (Navrátil et al 2007, Urban et al 2007a. Thus, the ratio between the blue (B; 400-500 nm) and red (R; 600-700 nm) spectral regions (B/R) varies from ≈ 0.5 (direct radiation) to ≈ 0.95 (diffuse solar radiation).…”

Section: Introductionmentioning

confidence: 99%

Blue radiation stimulates photosynthetic induction in Fagus sylvatica L.

Košvancová-Zitová¹,

Urban²,

Navrátil³

et al. 2009

Photosynt.

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This study was designed to test the hypothesis that the spectral composition of incident radiation, as defined by the relative proportions of blue (B; λ max = 455 nm) and red (R; λ max = 625 nm) photons, can affect photosynthetic induction, since B photons stimulate stomatal opening and are more effectively absorbed by leaves than R photons. Different stages of photosynthetic induction, primarily determined by the photo-modulation of Rubisco activity and stomata opening, were investigated in dark-adapted leaves of Fagus sylvatica transferred to saturating irradiance [800µmol(photon) m -2 s -1 ] at B/R ratios of 1/3, 1/1, or 3/1.In agreement with our hypothesis, photosynthesis was induced faster by irradiance with a high B/R ratio (3/1); as demontrated by a higher IS 60 (induction state 60 s after leaf illumination) and lower T 90 (the time period required to reach 90 % of maximum steady-state photosynthesis). However, there were no differences in induction between leaves receiving equal (1/1) and low (1/3) B/R ratios. Electron transport was highly sensitive to radiation quality, exhibiting faster induction kinetics with increasing B/R ratio. Such stimulation of carbon-assimilatory processes corresponds with faster activation of Rubisco and lower non-photochemical quenching (NPQ) as the proportion of B photons is increased. In contrast, the kinetics of stomatal opening was independent of the spectral composition of incoming radiation. Since slightly higher absorption efficiency of high B/R radiation does not fully explain the changes in induction kinetics, the other possible mechanisms contributing to the stimulation of electron transport and Rubisco activity are discussed.Additional keywords: blue/red ratio, electron transport, non-photochemical quenching, radiation quality, Rubisco activation, transient limitations of photosynthesis.

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“…Urban et al (2007Urban et al ( , 2012 hypothesised that optimal photosynthetic activity of the canopy is achieved under diffuse radiation (cloudy) conditions, when scattered light penetrates throughout the canopy, illuminating all the leaves to some extent and providing a more uniform distribution of light between the leaves. However, the spectral properties of the diffuse component inside the canopy have only been investigated in a Norway spruce (Picea abies L. Karst)-European beech (Fagus sylvatica L.) forest stand in Southern Germany (Leuchner et al, 2007;Hertel et al, 2011) and a Norway spruce stand by Navrátil et al (2007) and Urban et al (2007Urban et al ( , 2012 in the Czech Republic. No measurements are known from higher latitudes.…”

Section: Introductionmentioning

confidence: 99%

Transmissivity of solar radiation within a <i>Picea sitchensis</i> stand under various sky conditions

2015

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Abstract. We tested the hypothesis that diffuse radiation from cloudy and overcast skies penetrates the canopy more effectively than direct radiation from clear skies. We compared the flux density and spectral properties of direct and diffuse radiation (around solar noon (±1 h)) above, within and below a forest stand under sunny, cloudy and overcast conditions in a thinned Sitka spruce (Picea sitchensis (Bong.) Carr.) forest (28 years old, with a leaf area index of approximately 5.2 m 2 m −2 ). We recorded vertical profiles of radiation penetration (from 350 to 1050 nm), and we also explored the horizontal pattern of radiation along a 115 m transect.We showed that in "clear sky" conditions, the photosynthetically active radiation in the lower parts of the canopy was substantially attenuated, more so than under cloudy and overcast skies. It was particularly depleted in the blue part of the spectrum, but only slightly blue-depleted when the sky was overcast or cloudy. Moreover, the red : far-red ratio under clear skies fell to values less than 0.3 but only to 0.6 under cloudy or overcast skies. Near the ground, the light climate was strongly influenced by the thinning pattern (carried out in accordance with standard forestry management practice).

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Spectral composition of photosynthetically active radiation penetrating into a Norway spruce canopy: the opposite dynamics of the blue/red spectral ratio during clear and overcast days

Cited by 41 publications

References 54 publications

Canopy effects on vegetation caused by harvesting and regeneration treatments

Canopy effects on vegetation caused by harvesting and regeneration treatments

Blue radiation stimulates photosynthetic induction in Fagus sylvatica L.

Transmissivity of solar radiation within a <i>Picea sitchensis</i> stand under various sky conditions

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Spectral composition of photosynthetically active radiation penetrating into a Norway spruce canopy: the opposite dynamics of the blue/red spectral ratio during clear and overcast days

Cited by 41 publications

References 54 publications

Canopy effects on vegetation caused by harvesting and regeneration treatments

Canopy effects on vegetation caused by harvesting and regeneration treatments

Blue radiation stimulates photosynthetic induction in Fagus sylvatica L.

Transmissivity of solar radiation within a &lt;i&gt;Picea sitchensis&lt;/i&gt; stand under various sky conditions

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Transmissivity of solar radiation within a <i>Picea sitchensis</i> stand under various sky conditions