scholarly journals Carbon gain optimization in five broadleaf deciduous trees in response to light variation within the crown: correlations among morphological, anatomical and physiological leaf traits

2015 ◽  
Vol 74 (1) ◽  
pp. 71-94 ◽  
Author(s):  
Rosangela Catoni ◽  
Loretta Gratani ◽  
Francesco Sartori ◽  
Laura Varone ◽  
Mirko U. Granata
Keyword(s):  
Phenotypic Plasticity ◽  
Deciduous Forest ◽  
Light Variation ◽  
Stress Factors ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Carbon Gain ◽  
Deciduous Species ◽  
Shade Leaves ◽  
Sun Leaves

AbstractLeaf trait variations in five deciduous species (Quercus robur, Corylus avellana, Populus alba, Acer campestre, Robinia pseudoacacia) growing in an old broadleaf deciduous forest in response to light variation within the tree crown was analyzed. Net photosynthetic rate (PN), leaf respiration rate (R) and the photosynthetic nitrogen use efficiency were, on average, more than 100% higher in sun than in shade leaves. A. campestre and C. avellana sun leaves had the highest specific leaf area (SLA, 156.0 ± 17.9 cm2 g-1) and the lowest total leaf thickness (L, 101.9 ± 8.8 μm) underlining their shade-tolerance. Among the shade-intolerant species (Q. robur, P. alba and R. pseudoacacia), Q. robur had the lowest SLA and the highest L in sun leaves (130.6 ± 10.0 cm2 g-1 and 160.8 ± 9.6 μm, respectively) since shade-intolerant species typically have thicker leaves. The higher PN decrease in respect to R decrease from sun to shade leaves attested the higher sensitivity of PN than R to light variations within the crown. This determined a 69% lower R/PN in sun than in shade leaves. This result is further attested by the significant correlation between PN and the relative photosynthetic photon flux density. The shade-tolerant species have a 76% higher R/PN ratio than the shade-intolerant ones. The measured leaf phenotypic plasticity (PI = 0.35) was in the range of broadleaf deciduous species. Plasticity is a key trait useful to quantify plant response to environmental stimuli. It is defined as the ability of a genotype to produce different phenotypes depending on the environment. Among the considered species, Q. robur showed the highest PI (0.39) and P. alba the lowest (0.29). Knowledge on phenotypic plasticity is important in making hypotheses about the dynamics of the studied forest in consideration of environmental stress factors, including invasive species competition and global climate change.

scholarly journals The effects of sooty mold on photosynthesis and mesophyll structure of mahogany (Swietenia macrophylla King., Meliaceae)

Bragantia ◽  
2006 ◽  
Vol 65 (1) ◽  
pp. 11-17 ◽  
Author(s):  
José Pires de Lemos Filho ◽  
Élder Antônio Sousa Paiva
Keyword(s):  
Incident Light ◽  
Light Availability ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Effective Quantum Yield ◽  
Swietenia Macrophylla ◽  
Sooty Mold ◽  
Fluorescence Measurements ◽  
Shade Leaves ◽  
Sun Leaves

The aim of present study was to evaluate the effects of the sooty mold on anatomy and photochemical activity of mahogany (Swietenia macrophylla) leaves. The photochemical features of shade-developed leaves with or without sooty mold were compared to those of sun leaves using chlorophyll a fluorescence measurements. Leaf anatomy was also evaluated using conventional techniques. The degree of blockage of the photosynthetic active photon flux density (PPFD) by sooty mold and its effect on photochemistry were evaluated. Sun leaves showed thick mesophyll with palisade parenchyma disposed in a uniseriate layer, whereas shade leaves showed narrow mesophyll, independently of sooty mold presence. The effective quantum yield (deltaF/Fm') and the apparent electron transport rate (ETR) of sun leaves were higher than those of shade leaves. The values of ETR suggested that photochemistry saturation occurred at lower PPFD in shade-grown plants. Lower values of the deltaF/Fm' and, consequently, lower values of ETR were observed in leaves with sooty mold. A reduction of 40% of the incident light was seen due to physical blockage by sooty mold which is presumably responsible for an additional decrease of ETR values. Our data indicated that sooty mold did not directly damage the leaf, but reduce leaf photochemistry capacity, by decreasing light availability.

Influence of radiation and CO2 enrichment on whole plant net CO2 exchange in roses

1991 ◽  
Vol 71 (1) ◽  
pp. 245-252 ◽  
Author(s):  
J. Jiao ◽  
M. J. Tsujita ◽  
B. Grodzinski
Keyword(s):  
Exchange Rate ◽  
Radiant Energy ◽  
Co2 Enrichment ◽  
Co2 Exchange ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Carbon Gain ◽  
Flower Bud ◽  
Whole Plant ◽  
Bud Size

At three stages of flowering shoot development, varying the irradiance and CO2 levels had a similar effect on the whole-plant net CO2 exchange rate (NCER) of Samantha rose plants. At 22 °C, the NCER was saturated at 1000 μmol m−2 s−1 photosynthetically active radiation (PAR). The duration of the light period was also important in determining daily carbon (C) gain. When roses were exposed to a constant daily radiant energy dose of 17.6 μmol m−2 provided either as a 12-h irradiation interval at 410 μmol m−2 s−1 PAR or 24 h of irradiation at 204 μmol m−2 s−1 PAR, the plants exposed to 24 h of continuous irradiation at the lower photon flux density retained 80% more C. Under saturating irradiance, the net photosynthetic rate at an enriched (1000 μL L−1) CO2 level was almost double that at ambient (350 μL L−1) CO2. However, plants grown at ambient and enriched CO2 levels had similar whole-plant NCERs when compared at the same assay CO2 level. Under CO2 enrichment the flower stem was longer and thicker but the flower bud size at harvest was not significantly different to that of roses grown at the ambient CO2 level. Key words: CO2 enrichment, daily carbon gain, net CO2 exchange rate, radiation, Rosa hybrida

Canopy dynamics and light climates in a tropical moist deciduous forest in India

1989 ◽  
Vol 5 (1) ◽  
pp. 65-79 ◽  
Author(s):  
David W. Lee
Keyword(s):  
Deciduous Forest ◽  
Canopy Cover ◽  
Tectona Grandis ◽  
Photosynthetic Photon Flux Density ◽  
Radiation Environment ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photon Fluence ◽  
East End ◽  
Individual Trees

ABSTRACTThe canopy dynamics and light climates within a 20 by 60 m quadrat were studied in a disturbed moist deciduous forest near Bombay, India. A map was drawn of individual trees within the quadrat, the taxa were identified, and their phenology was followed from November 1984 to July 1985. The quadrat contained 14 species, the most common being Tectona grandis, Terminalia tomentosa, Butea monosperma, Mitragyne parviflora and Albizia procera. Some individuals were in leaf at all times, more so at the moister east end of the quadrat. In November at the end of the rainy season, light measurements documented percentages of total daily photosynthetic photon fluence (PPF) at 10.0% of full sunlight; 44% of this flux was due to sun-flecks whose duration was approximately 17% of the daytime hours. Values for six sites were similar to mid-day measurements along a 40 m transect, and consistent with the 94% canopy cover of the sites, photographed with a fish-eye lens. The March dry season measurements revealed a more intense radiation environment (54% of solar PPF), and 59% of the photosynthetic photon flux density at mid-day along the transect. Canopy openings were increased to a mean of 59.4%. Light in the understorey in November was spectrally altered, with typical R:FR ratios of 0.30, compared to March values identical to those of sunlight, at 1.10.

CARBON GAIN IN COFFEA ARABICA DURING CLEAR AND CLOUDY DAYS IN THE WET SEASON

2006 ◽  
Vol 42 (2) ◽  
pp. 147-164 ◽  
Author(s):  
J. C. RONQUIM ◽  
C. H. B. A. PRADO ◽  
P. NOVAES ◽  
J. I. FAHL ◽  
C. C. RONQUIM
Keyword(s):  
Gas Exchange ◽  
Coffea Arabica ◽  
Leaf Gas Exchange ◽  
Photochemical Efficiency ◽  
Vapour Pressure Deficit ◽  
Net Photosynthesis ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Carbon Gain ◽  
Wet Season

Three cultivars of Coffea arabica, Catuaí Vermelho IAC 81, Icatu Amarelo IAC 2944 and Obatã IAC 1669–20, were evaluated in relation to leaf gas exchange and potential photochemical efficiency of photosystem II under field conditions on clear and cloudy days in the wet season in southeast Brazil. Independent of levels of irradiance, leaf water potential (υleaf) values were always higher than the minimum required to affect daily net photosynthesis (PN). PN, stomatal conductance (gs), leaf transpiration (E) and the index of photochemical efficiency (Fv/Fm) declined on a clear day in all cultivars. The depression of leaf gas exchange and Fv/Fm (specially around midday) caused a strong decrease (about 70 %) in daily carbon gain on a clear day. Under cloudless conditions, gs and PN were correlated with the air vapour pressure deficit (VPDair), but not with photosynthetic photon flux density (PPFD) values. On a cloudy day, the daily carbon gain was barely limited by PPFD below 800 μmol m−2 s−1, the Fv/Fm values showed a slight decrease around midday, and gs and PN were positively correlated with PPFD but not with VPDair. By contrast, irrespective of the contrasting irradiance conditions during the day, PN and E were correlated with gs.

Photoregulation and photodamage in Schefflera arboricola leaves adapted to different light environments

1999 ◽  
Vol 26 (5) ◽  
pp. 485 ◽  
Author(s):  
U. Schiefthaler ◽  
A. W. Russell ◽  
H. R. Bolhàr-Nordenkampf ◽  
C. Critchley
Keyword(s):  
Xanthophyll Cycle ◽  
De Novo ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Synthesis Rate ◽  
Long Term Effects ◽  
Photosynthetic Rates ◽  
Full Sunlight ◽  
Schefflera Arboricola ◽  
Sun Leaves

Leaves of the subtropical understorey shrub Schefflera arboricola Hayata growing in full sunlight had higher specific leaf weight, higher chlorophyll a/b ratios, lower total chlorophyll content and a threefold higher xanthophyll cycle pigment content than leaves growing in a naturally shaded, but sunfleck-punctuated, environment. A number of measurements, all made in situ and during natural day/night cycles, were taken as follows: current photochemical capacity (F√F m after 10 min dark-adaptation), size and epoxidation state of the xanthophyll cycle, CO 2 gas exchange and determination of the D1 synthesis rate. In sun leaves the lowest daily F√F m was found to be approximately 0.6, the change from maximum correlating with an increase in zeaxanthin. Daily changes in zeaxanthin were partly due to de novo synthesis and turnover. We suggest that sun leaves can dissipate most of the excess light energy absorbed safely via the photoprotective xanthophyll cycle. D1 synthesis rates did not correlate with photosynthetic photon flux density or F√F m . The shade leaves had high F√F m values and constant photosynthetic rates throughout the day except during sunflecks, when photosynthetic rates increased and D1 synthesis accelerated, all without a substantial decrease in F√F m . It seems that leaves of S. arboricola adapted to natural shade conditions can use sunflecks to contribute significantly to their pro-ductivity. The third leaf type investigated was from greenhouse-grown plants of S. arboricola after exposure to full sunlight. These leaves showed a rapid and large reduction in F√F m (to 0.3), which neither correlated with zeaxanthin formation nor recovered within the same day. From long-term effects following full sunlight exposure of greenhouse-grown plants we suggest that this F√F m reduction actually reflects photodestruction.

scholarly journals Photosynthetic Light Response and Epidermal Characteristics of Sun and Shade Pecan Leaves

2009 ◽  
Vol 134 (3) ◽  
pp. 372-378 ◽  
Author(s):  
Leonardo Lombardini ◽  
Hermann Restrepo-Diaz ◽  
Astrid Volder
Keyword(s):  
Leaf Area ◽  
Management Practices ◽  
Light Response ◽  
Tree Canopy ◽  
Photon Flux ◽  
Leaf Type ◽  
Chl A ◽  
Sun And Shade ◽  
Shade Leaves ◽  
Sun Leaves

An experiment was conducted to investigate the morphologic characteristics and photosynthetic response of sun and shade leaves of mature pecan [Carya illinoinensis (Wangenh.) K. Koch] trees. Treatments were established according to leaf type (sun or shade leaves) and cultivar (Pawnee and Stuart). Sun leaves were chosen from those growing on exterior portions of the tree canopy and exposed to full sunlight for most of the day [≥1500 μmol·m−2·s−1 photosynthetic photon flux (PPF)]. Shade leaves were those growing in interior parts of the tree canopy (≤100 μmol·m−2·s−1 PPF). Epidermis characteristics, leaf area, and chlorophyll (Chl) content were also measured. Results indicated that stomatal density (stomata/mm2), leaf area, and leaflet area were greater in sun leaves than in shade leaves in both cultivars investigated. Specific leaf area was greater in shade leaves than sun leaves. Chlorophyll fluorescence, total Chl content, Chl a, Chl b, and Chl a/b were unaffected by leaf type or cultivar. In both cultivars, photosynthetic light response curves showed that area-based maximum assimilation rate (Amax) in shade leaves was about half of that measured in sun leaves in June through August. However, in October, Amax of sun leaves dropped to values similar to those measured in shade leaves. Light compensation point of photosynthesis and dark respiration rate were always lower in shade leaves than in sun leaves. Overall, there were only minor differences between the cultivars. Pecan trees require careful canopy management to avoid self shading and to maintain productivity. These results could help determine optimal levels of canopy light interception and could be used to develop canopy and crop management practices.

Effect of Canopy Position on the Susceptibility of Kiwifruit (Actinidia deliciosa) Leaves on Vines in an Orchard Environment to Photoinhibition Throughout the Growing Season

1995 ◽  
Vol 22 (2) ◽  
pp. 299 ◽  
Author(s):  
DH Greer
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosynthetic Capacity ◽  
Growing Season ◽  
Actinidia Deliciosa ◽  
Photon Flux ◽  
Photon Yield ◽  
Canopy Position ◽  
Shade Leaves ◽  
Sun Leaves ◽  
The Impact

Kiwifruit (Actinidia deliciosa (A. Chev) C.F. Liang & A.R. Ferguson) plants grown in an orchard were studied over several seasons to assess the impact of photoinhibition on the leaves using chlorophyll fluorescence and photosynthetic measurements. Leaves above were compared with those below the vine canopy. In addition, temperature and photon flux densities above and below the canopy were monitored. A gradient of sun to shade photosynthetic characteristics developed in leaves from above to below the canopy. There was a 10% higher Fv/Fm ratio in the shade leaves (0.810) but a 30% lower photosynthetic capacity and a 30% higher photon yield than in sun leaves. In addition, Fo and Fm were both higher (20-60%) in shade leaves. Little variation in Fv/Fm occurred throughout the growing season, except during spring, when Fv/Fm was about 0.4-0.5, especially in small, rapidly expanding leaves. Changes in Fv/Fm during spring were correlated with leaf diameter, indicating development of photosynthetic competence was an important factor in the rise in Fv/Fm. However, increasing night temperatures also correlated with the increase in Fv/Fm during spring.

Intracanopy variation in leaf morphology and physiology in dominant shrubs of Florida’s xeric uplands

Botany ◽  
2009 ◽  
Vol 87 (1) ◽  
pp. 112-125 ◽  
Author(s):  
Elizabeth L. Stephens ◽  
Sonali Saha ◽  
Eric S. Menges
Keyword(s):  
Structure Function ◽  
Leaf Area ◽  
Specific Leaf Area ◽  
Morphological Traits ◽  
Light Attenuation ◽  
Photon Flux ◽  
Shade Leaves ◽  
Sun Leaves ◽  
Rosemary Scrub ◽  
Photosynthetic Traits

The variation in morphological traits and photosynthetic potentials associated with light conditions in the canopy can determine whole-plant function. However, leaf structure–function relationships are poorly studied in ecosystems experiencing nominal light attenuation. We examined morphological leaf traits (area, specific leaf area, thickness, revoluteness, length–width) and photosynthetic traits estimated from rapid light curves (PARsat, ETRmax, light harvesting efficiency α) in seven shrub species in two xeric upland ecosystems of Florida: rosemary scrub and sandhill. Across species and ecosystem types, shade leaves had greater specific leaf area, were thinner, and less revolute than sun leaves. Surprisingly, shade leaves had smaller areas than sun leaves. Three out of six species showed a tight relationship between morphological and photosynthetic traits. Species common to both sandhill and rosemary scrub ecosystems showed similar photosynthetic traits but greater sclerophylly in the scrub ecosystem. Overall, greater leaf thickness and greater leaf area of upper canopy leaves yielded higher photosynthetic capacities and saturation at higher photon flux densities compared with lower canopy leaves. Our results suggest that variation in leaf morphological traits governed by patterns in light availability have functional significance; however, ecosystem properties such as nutrient availability might also impact light-driven structure-function relationships.

Variation of phenotypic responses to lighting using a combination of red and blue light-emitting diodes versus darkness in seedlings of 18 vegetable genotypes

2019 ◽  
Vol 99 (2) ◽  
pp. 159-172
Author(s):  
Yun Kong ◽  
Youbin Zheng
Keyword(s):  
Phenotypic Plasticity ◽  
Light Emitting Diodes ◽  
Plant Traits ◽  
Germination Rate ◽  
Shoot Length ◽  
Fresh Mass ◽  
Plasticity Index ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Light Emitting

The objectives of this study were to identify traits and screen genotypes sensitive to narrow-waveband light-emitting diode light in 18 vegetable genotypes. Their phenotypic plasticity responses were examined under a combination of red (85%) and blue (15%) light-emitting diodes relative to darkness from seed germination to cotyledon unfolding. The photosynthetic photon flux density was around 316 μmol m−2 s−1 and the photoperiod was 17 h. Generally, light vs. dark delayed germination by reducing germination rate and increasing spread time of germination; inhibited shoot growth by reducing shoot length and fresh mass; promoted root growth by increasing root length, diameter, branching, and fresh mass; and promoted genotype-inherent colouring in leaves and stems. Shoot colour, shoot length, and (or) root branching showed higher plasticity indices than other plant traits in response to light, suggesting that some or all of these plant traits are more sensitive to lighting across the tested genotypes. Using cluster analysis based on the plasticity index, the 18 genotypes were separated into six groups that expressed response sensitivity to part or all of the above-mentioned traits. Based on the average plasticity index of all the tested plant traits, the 18 genotypes were graded into four groups using the Fisher optimal partition. Small- vs. large-seed species and the red- vs. green-leaf/root cultivars within the same species showed higher phenotypic plasticity indices in most cases, suggesting that they are more sensitive to lighting.

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