The effect of reduced quantities of photosynthetically active radiation on Fraxinus pennsylvanica growth and architecture

1998 ◽  
Vol 76 (8) ◽  
pp. 1359-1365 ◽  
Author(s):  
G A Bartlett ◽  
W R Remphrey
Keyword(s):  
Photosynthetically Active Radiation ◽  
Shoot Growth ◽  
Unit Length ◽  
Shoot Biomass ◽  
Fraxinus Pennsylvanica ◽  
Green Ash ◽  
Seedling Morphology ◽  
Active Radiation ◽  
Shade Tolerant Species ◽  
Light Quantity

The quantity and quality of light have significant effects on tree growth and architecture that can be highly variable depending on the shade tolerance of the species. A study was conducted to determine the effect of decreased availability of photosynthetically active radiation (PAR) on the growth and architecture of green ash (Fraxinus pennsylvanica var. subintegerrima (Vahl) Fern.), a moderately shade-tolerant species. Twenty-four seedlings were planted in each of five shade treatments (4, 8, 20, 40, and 100% of full sun, respectively). Measurements made over a 2-year period revealed that with decreased PAR levels there was generally a reduction in leaf thickness, number of shoot units per shoot, shoot-unit length, shoot growth, branching frequency, lateral shoot growth, and shoot biomass. However, in moderate reductions of PAR, there were increases in shoot unit numbers, overall shoot length, and branch numbers. The overall effect of heavy shading was to produce a tree with little height growth and a poorly developed crown.Key words: Fraxinus, shading, seedling morphology, shoot unit, light quantity, architecture.

scholarly journals A Window Into Below-ground Growth of Landscape Trees: Implications for Transplant Success

1994 ◽  
Vol 4 (4) ◽  
pp. 368-371
Author(s):  
Roger Harris ◽  
Nina L. Bassuk ◽  
Thomas H. Whitlow
Keyword(s):  
Root Growth ◽  
Root Length ◽  
Shoot Growth ◽  
Fraxinus Pennsylvanica ◽  
Green Ash ◽  
Root And Shoot Growth ◽  
Below Ground ◽  
Tree Transplanting ◽  
Shoot Phenology ◽  
Landscape Trees

Root and shoot phenology were observed, and root length within rootballs were calculated for Fraxinus pennsylvanica Marsh. (green ash), Quecus coccinea Muenchh. (scarlet oak), Corylus colurna L. (Turkish hazelnut), and Syringa reticulata (Blume) Hara `Ivory Silk' (tree lilac) trees established in a rhizotron. Easy-to-transplant species (green ash and tree lilac) had more root length within rootballs than difficult-to-transplant species (Turkish hazelnut and scarlet oak). Shoot growth began before root growth on all species except scarlet oak, which began root and shoot growth simultaneously. Fall root growth ceased for all species just after leaf drop. Implications for tree transplanting are discussed.

scholarly journals A STUDY ON ECOTECT APPLICATION OF LOCAL CLIMATE AT A RESIDENTIAL AREA IN CHUNCHEON, KOREA

2015 ◽  
Vol 23 (2) ◽  
pp. 94-101 ◽  
Author(s):  
Qian WU ◽  
Hyun-Kil JO
Keyword(s):  
Photosynthetically Active Radiation ◽  
Residential Area ◽  
Analysis Tool ◽  
Climate Data ◽  
Residential Areas ◽  
Neutral Species ◽  
Local Climate ◽  
Active Radiation ◽  
Building Orientation ◽  
Shade Tolerant Species

The local climate data were investigated at a residential area in Chuncheon from May to October in 2013.In addition, the simulations were carried out by the Autodesk Ecotect Analysis tool. Site A had the lowest temperature in summer. The best building orientation was south by east 157.5°. Based on the photosynthetically active radiation(PAR) values day-neutral species should be planted around sites C and E, shade-tolerant species around site D and helioplous species around sites A and B. In addition, site A is the most comfortable place in the residential area with a predicted mean vote (PMV) value around 0. It was found that there were four main aspects to be considered for the residential designs which were building height, land cover, planting design and building orientation. Moreover, the results showed that local climate and shading conditions should be of great concern in design or improvement of residential areas.

scholarly journals A microbiota–root–shoot circuit favours Arabidopsis growth over defence under suboptimal light

Nature Plants ◽  
2021 ◽  
Author(s):  
Shiji Hou ◽  
Thorsten Thiergart ◽  
Nathan Vannier ◽  
Fantin Mesny ◽  
Jörg Ziegler ◽  
...  
Keyword(s):  
Stress Responses ◽  
Photosynthetically Active Radiation ◽  
Bacterial Community Composition ◽  
Light Condition ◽  
Long Distance ◽  
Active Radiation ◽  
Light Manipulation ◽  
Growth Deficiency ◽  
Dependent Growth ◽  
Control Light

AbstractBidirectional root–shoot signalling is probably key in orchestrating stress responses and ensuring plant survival. Here, we show that Arabidopsis thaliana responses to microbial root commensals and light are interconnected along a microbiota–root–shoot axis. Microbiota and light manipulation experiments in a gnotobiotic plant system reveal that low photosynthetically active radiation perceived by leaves induces long-distance modulation of root bacterial communities but not fungal or oomycete communities. Reciprocally, microbial commensals alleviate plant growth deficiency under low photosynthetically active radiation. This growth rescue was associated with reduced microbiota-induced aboveground defence responses and altered resistance to foliar pathogens compared with the control light condition. Inspection of a set of A. thaliana mutants reveals that this microbiota- and light-dependent growth–defence trade-off is directly explained by belowground bacterial community composition and requires the host transcriptional regulator MYC2. Our work indicates that aboveground stress responses in plants can be modulated by signals from microbial root commensals.

scholarly journals Intercepted Photosynthetically Active Radiation (PAR) and Spatial and Temporal Distribution of Transmitted PAR under High-Density and Super High-Density Olive Orchards

Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 351
Author(s):  
Adolfo Rosati ◽  
Damiano Marchionni ◽  
Dario Mantovani ◽  
Luigi Ponti ◽  
Franco Famiani
Keyword(s):  
Spatial Variability ◽  
Photosynthetically Active Radiation ◽  
Temporal Distribution ◽  
High Density ◽  
Radiation Use Efficiency ◽  
Spatial And Temporal Distribution ◽  
Active Radiation ◽  
Use Efficiency ◽  
And Performance ◽  
Radiation Use

We quantified the photosynthetically active radiation (PAR) interception in a high-density (HD) and a super high-density (SHD) or hedgerow olive system, by measuring the PAR transmitted under the canopy along transects at increasing distance from the tree rows. Transmitted PAR was measured every minute, then cumulated over the day and the season. The frequencies of the different PAR levels occurring during the day were calculated. SHD intercepted significantly but slightly less overall PAR than HD (0.57 ± 0.002 vs. 0.62 ± 0.03 of the PAR incident above the canopy) but had a much greater spatial variability of transmitted PAR (0.21 under the tree row, up to 0.59 in the alley center), compared to HD (range: 0.34–0.43). This corresponded to greater variability in the frequencies of daily PAR values, with the more shaded positions receiving greater frequencies of low PAR values. The much lower PAR level under the tree row in SHD, compared to any position in HD, implies greater self-shading in lower-canopy layers, despite similar overall interception. Therefore, knowing overall PAR interception does not allow an understanding of differences in PAR distribution on the ground and within the canopy and their possible effects on canopy radiation use efficiency (RUE) and performance, between different architectural systems.

scholarly journals Estimation of Incident Photosynthetically Active Radiation from GOES Visible Imagery

2008 ◽  
Vol 47 (3) ◽  
pp. 853-868 ◽  
Author(s):  
Tao Zheng ◽  
Shunlin Liang ◽  
Kaicun Wang
Keyword(s):  
Photosynthetically Active Radiation ◽  
Terrestrial Ecosystem ◽  
New Method ◽  
High Temporal Resolution ◽  
Atmospheric Conditions ◽  
Ecosystem Models ◽  
Surface Conditions ◽  
Active Radiation ◽  
Ground Measurement ◽  
Visible Imagery

Abstract Incident photosynthetically active radiation (PAR) is an important parameter for terrestrial ecosystem models. Because of its high temporal resolution, the Geostationary Operational Environmental Satellite (GOES) observations are very suited to catch the diurnal variation of PAR. In this paper, a new method is developed to derive PAR using GOES data. What makes this new method distinct from the existing method is that it does not need external knowledge of atmospheric conditions. The new method retrieves both atmospheric and surface conditions using only at-sensor radiance through interpolation of time series of observations. Validations against ground measurement are carried out at four “FLUXNET” sites. The values of RMSE of estimated and ground-measured instantaneous PAR at the four sites are 130.71, 131.44, 141.16, and 190.22 μmol m−2 s−1, respectively. At the four validation sites, the RMSE as the percentage of estimated mean PAR value are 9.52%, 13.01%, 13.92%, and 24.09%, respectively; the biases are −101.54, 16.56, 11.09, and 53.64 μmol m−2 s−1, respectively. The independence of external atmospheric information enables this method to be applicable to many situations in which external atmospheric information is not available. In addition, topographic impacts on surface PAR are examined at the 1-km resolution at which PAR is retrieved using the GOES visible band data.

Canopy development and hydraulic function in Eucalyptus tereticornis grown in drought in CO2-enriched atmospheres

2007 ◽  
Vol 34 (12) ◽  
pp. 1137 ◽  
Author(s):  
Brian J. Atwell ◽  
Martin L. Henery ◽  
Gordon S. Rogers ◽  
Saman P. Seneweera ◽  
Marie Treadwell ◽  
...  
Keyword(s):  
Elevated Co2 ◽  
Shoot Growth ◽  
Co2 Enrichment ◽  
Atmospheric Co2 ◽  
Shoot Biomass ◽  
Eucalyptus Tereticornis ◽  
Growth Responses ◽  
Ambient Conditions ◽  
Long Distance ◽  
Pipe Model

We report on the relationship between growth, partitioning of shoot biomass and hydraulic development of Eucalyptus tereticornis Sm. grown in glasshouses for six months. Close coordination of stem vascular capacity and shoot architecture is vital for survival of eucalypts, especially as developing trees are increasingly subjected to spasmodic droughts and rising atmospheric CO2 levels. Trees were exposed to constant soil moisture deficits in 45 L pots (30–50% below field capacity), while atmospheric CO2 was raised to 700 μL CO2 L–1 in matched glasshouses using a hierarchical, multi-factorial design. Enrichment with CO2 stimulated shoot growth rates for 12–15 weeks in well-watered trees but after six months of CO2 enrichment, shoot biomasses were not significantly heavier (30% stimulation) in ambient conditions. By contrast, constant drought arrested shoot growth after 20 weeks under ambient conditions, whereas elevated CO2 sustained growth in drought and ultimately doubled the shoot biomass relative to ambient conditions. These growth responses were achieved through an enhancement of lateral branching up to 8-fold due to CO2 enrichment. In spite of larger transpiring canopies, CO2 enrichment also improved the daytime water status of leaves of droughted trees. Stem xylem development was highly regulated, with vessels per unit area and cross sectional area of xylem vessels in stems correlated inversely across all treatments. Furthermore, vessel numbers related to the numbers of leaves on lateral branches, broadly supporting predictions arising from Pipe Model Theory that the area of conducting tissue should correlate with leaf area. Diminished water use of trees in drought coincided with a population of narrower xylem vessels, constraining hydraulic capacity of stems. Commensurate with the positive effects of elevated CO2 on growth, development and leaf water relations of droughted trees, the capacity for long-distance water transport also increased.

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