scholarly journals Growth, biomass allocation and photosynthesis of Rolandra fruticosa (asteraceae) in response to shade

2000 ◽  
Vol 18 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Moacyr B. Dias-Filho ◽  
Aloisio F. Chagas Júnior
Keyword(s):  
Leaf Area ◽  
Biomass Allocation ◽  
Weed Management ◽  
Dark Respiration ◽  
Experimental Period ◽  
Perennial Weed ◽  
Full Sunlight ◽  
Shade Leaves ◽  
Sun Leaves ◽  
Shade Plants

The effects of shade on growth, biomass allocation patterns and photosynthetic response was examined for Rolandra fruticosa (L.) Kuntze, a common perennial weed shrub in cultivated pastures and agricultural areas of Brazilian Amazonia, for plants grown in full sunlight and those shaded to 30 % of full sunlight over a 34-d period. Specific leaf area and leaf area ratio were higher for shade plants during all the experimental period. Shade plants allocated significantly less biomass to root tissue than sun plants and relative growth rate was higher in sun plants. Sun leaves had significantly higher dark respiration and light saturated rates of photosynthesis than shade leaves. The apparent quantum efficiency was higher for shade leaves, while light compensation point was higher for sun leaves. These results are discussed in relation to their ecological and weed management implications.

scholarly journals Growth and biomass allocation of the C4 grasses Brachiaria brizantha and B. humidicola under shade

2000 ◽  
Vol 35 (12) ◽  
pp. 2335-2341 ◽  
Author(s):  
MOACYR BERNARDINO DIAS-FILHO
Keyword(s):  
Leaf Area ◽  
Biomass Allocation ◽  
Leaf Tissue ◽  
Experimental Period ◽  
High Light ◽  
Brachiaria Brizantha ◽  
Pasture Management ◽  
Low Light ◽  
Allocation Pattern ◽  
Full Sunlight

The growth and biomass allocation responses of the tropical forage grasses Brachiaria brizantha cv. Marandu and B. humidicola were compared for plants grown outdoors, in pots, in full sunlight and those shaded to 30% of full sunlight over a 30day period. The objective was to evaluate the acclimation capacity of these species to low light. Both species were able to quickly develop phenotypic adjustments in response to low light. Specific leaf area and leaf area ratio were higher for low-light plants during the entire experimental period. Low-light plants allocated significantly less biomass to root and more to leaf tissue than high-light plants. However, the biomass allocation pattern to culms was different for the two species under low light: it increased in B. brizantha, but decreased in B. humidicola, probably as a reflection of the growth habits of these species. Relative growth rate and tillering were higher in high-light plants. Leaf elongation rate was significantly increased on both species under low light; however, the difference between treatments was higher in B. brizantha. These results are discussed in relation to the pasture management implications.

scholarly journals Growth and Photosynthetic Responses of Three Lycoris Species to Levels of Irradiance

HortScience ◽  
2008 ◽  
Vol 43 (1) ◽  
pp. 134-137 ◽  
Author(s):  
Panpan Meng ◽  
Ying Ge ◽  
Qianjin Cao ◽  
Jie Chang ◽  
Peng Pan ◽  
...  
Keyword(s):  
Biomass Production ◽  
Biomass Allocation ◽  
Growth Traits ◽  
Net Photosynthesis ◽  
Experimental Period ◽  
High Irradiance ◽  
Cut Flowers ◽  
Full Sunlight ◽  
Green Leaves ◽  
Photosynthetic Responses

Lycoris species have appealing characteristics for potting plants, cut flowers, and landscaping decorations, including attractive foliage, which is very similar to that of cymbidium. Lycoris species have been extensively propagated and marketed in Asia. Understanding the response of Lycoris spp. to irradiance intensity will help the horticultural industry improve the production of potting plants of those species. We studied the responses of photosynthesis, growth, and biomass allocation of potted Lycoris spp. (L. chinensis, L. longituba, and L. sprengeri) bulbs grown under three levels of irradiance, i.e., 100%, 70%, and 30% full sunlight. We found that in terms of biomass production L. chinensis can be cultivated under all levels of irradiance studied from full to 30% sunlight. For L. longituba, high irradiance levels increased the rate of net photosynthesis. For both L. chinensis and L. longituba, the full sunlight treatment produced the most attractive plants characterized by shorter, wider, and darker green leaves, features that appeal to consumers. However, none of the growth traits of L. sprengeri were affected by the irradiance treatment over the entire experimental period. It can be concluded that potting plants of L. chinensis and L. longituba are best produced under full sunlight, whereas L. sprengeri can be produced under irradiance levels from 30% to full sunlight.

Effects of Shade on Silverleaf Nightshade (Solanum elaeagnifolium)

Weed Science ◽  
1982 ◽  
Vol 30 (3) ◽  
pp. 264-269 ◽  
Author(s):  
John W. Boyd ◽  
Don S. Murray
Keyword(s):  
Leaf Area ◽  
Dry Weight ◽  
Fruit Production ◽  
Full Sunlight ◽  
Unit Leaf ◽  
Matter Production ◽  
Silverleaf Nightshade ◽  
Structural Carbohydrate ◽  
Solanum Elaeagnifolium ◽  
Shade Leaves

Plants started with seed, 'seedlings', and established plants of silverleaf nightshade (Solanum elaeagnifoliumCav.) were grown in the field under shade levels of 0, 47, 63, and 92% of full sunlight to determine vegetative, reproductive, and physiological responses to shade. Dry-matter production of both 'seedling’ and established plants declined markedly with increasing shade levels. Established plants did not bear fruit under 92% shade, and 63% shade prevented fruit production by 'seedlings'. Taproots of plants grown in full sunlight contained 16% more total non-structural carbohydrate (TNC) per gram dry weight than taproots of plants grown under 92% shade. Leaves of established plants grown under moderate shade had significantly more chlorophyll per unit leaf fresh weight than plants grown in full sunlight; however, plants under heavy (92%) shade had 35% less chlorophyll per unit leaf area than unshaded plants. The chlorophylla/bratio of the 92%-shaded plants was significantly less than with other treatments. Leaf area increased, with increasing shade; however, leaf weight per unit area decreased because of thinner leaves. Photosynthetic rates of recently expanded leaves were 10.4, 4.6, 3.3, and 0.9 mg CO2· dm−2· h−1for the 0, 47, 63, and 92% shade treatments, respectively.

scholarly journals Are sun- and shade-type anatomy required for the acclimation of Neoregelia cruenta?

2013 ◽  
Vol 85 (2) ◽  
pp. 561-574 ◽  
Author(s):  
FERNANDA REINERT ◽  
MARCOS V. LEAL-COSTA ◽  
NICIA E. JUNQUEIRA ◽  
ELIANA S. TAVARES
Keyword(s):  
Growth Conditions ◽  
Sand Ridge ◽  
Light Levels ◽  
The Family ◽  
Sun And Shade ◽  
Shade Leaves ◽  
Sun Leaves ◽  
First Time ◽  
Tank Bromeliads ◽  
Shade Plants

Sun and shade plants are often discriminated by a number of sun- and shade-type anatomies. Nonetheless, we propose that among tank-bromeliads, changes in rosette architecture satisfy the requirements for coping with contrasting light levels. The tank-bromeliad Neoregelia cruenta naturally colonises sub-habitats ranging from full exposure to direct sunlight, to shaded environments in sand ridge plains. We quantified anatomical and morphological traits of leaves and rosettes of N. cruenta grown under sun and shade conditions. Cells with undulated lateral walls within the water parenchyma are for the first time described for the family. Under high light, leaf blades were wider, shorter, and yellowish. The rosette diameter of sun plants was less than half that of shade plants. Sun leaves overlapped with neighbouring leaves for most of their length, forming a cylindrical rosette where water accumulates. Shade leaves only overlapped in the centre of the rosette. Most anatomical traits were similar under both growth conditions. Stomata were absent from the base of sun leaves, which is probably explained by limited gas exchange at the base of the tight sun-type rosette. Data suggest that the ability of N. cruenta to acclimate to sun and shade is better explained by changes in rosette architecture than by leaf anatomy.

Sun and shade leaves: clues to how salal (Gaultheriashallon) responds to overstory stand density

1991 ◽  
Vol 21 (3) ◽  
pp. 300-305 ◽  
Author(s):  
N. J. Smith
Keyword(s):  
Leaf Area Index ◽  
Relative Density ◽  
Leaf Area ◽  
Stand Density ◽  
Leaf Biomass ◽  
Area Index ◽  
Sun And Shade Leaves ◽  
Sun And Shade ◽  
Shade Leaves ◽  
Sun Leaves

Salal (Gaultheriashallon Pursh) leaf biomass, leaf area index, specific leaf area, and leaf morphology were examined in 13 Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands from 37 destructively measured 1-m2 quadrats. In response to light and stand overstory density, salal shoots produced either mainly sun leaves or mainly shade leaves. Sun leaves were associated with sunflecks in open-grown or variably stocked stands. Shade leaves were associated with diffuse light under denser stands. Sun-leaf quadrats had mean specific leaf areas less than 90 cm2/g; shade-leaf quadrats had mean specific leaf areas greater than 90 cm2/g. Sun leaves were narrower, with average leaf widths less than 5 cm. Quadrat salal leaf biomass and leaf area index peaked at Curtis' metric relative density 5.9, which corresponded to an availability of 15% of global photosynthetically active radiation. Sun-leaf quadrats occurred below relative density 5; shade-leaf quadrats occurred above relative density 4. A mixture of sun- and shade-leaf quadrats occurred between about relative density 4 and 5, depending on the uniformity of stocking.

scholarly journals Nutritional status and specific leaf area of mahogany and tonka bean under two light environments

2005 ◽  
Vol 35 (1) ◽  
pp. 23-27 ◽  
Author(s):  
José Francisco de C. Gonçalves ◽  
Gil Vieira ◽  
Ricardo A. Marenco ◽  
João Baptista S. Ferraz ◽  
Ulysses Moreira dos Santos Junior ◽  
...  
Keyword(s):  
Nutritional Status ◽  
Leaf Area ◽  
Specific Leaf Area ◽  
Leaf Growth ◽  
Leaf Traits ◽  
Swietenia Macrophylla ◽  
Nutrient Contents ◽  
Full Sunlight ◽  
Successional Species ◽  
Sun Leaves

Studies on nutritional status and leaf traits were carried out in two tropical tree species Swietenia macrophylla King (mahogany) and Dipetryx odorata Aubl. Willd. (tonka bean) planted under contrasting light environments in Presidente Figueiredo-AM, Brazil. Leaves of S. macrophylla and D. odorata were collected in three year-old trees grown under full sunlight (about 2000 µmol m-2 s-1) and natural shade under a closed canopy of Balsa-wood plantation (Ochroma pyramidale Cav. Ex. Lam.Urb) about 260 µmol m-2 s-1. The parameters analysed were leaf area (LA), leaf dry mass (LDM), specific leaf area (SLA) and leaf nutrient contents. It was observed that, S. macrophylla leaves grown under full sunlight showed LA 35% lower than those grown under shade. In D. odorata leaves these differences in LA were not observed. In addition, it was observed that S. macrophylla shade leaves, for LDM, were 50% smaller than sun leaves, while in D. odorata, there differences were not observed. SLA in S. macrophylla presented that sun leaves were three times smaller than those grown under shade. In D. odorata, no differences were observed. Nutrient contents in S. macrophylla, regardless of their light environments, showed higher contents for P and Ca than those found in D. odorata. The N, K, Fe and Mn contents in S. macrophylla leaves decreased under shade. Finally, we suggest that the decreasing in leaf nutrient contents may have a negative influence on leaf growth. The results demonstrated that the tested hypothesis is true for leaf traits, which D. odorata, late-successional species, showed lower plasticity for leaf traits than Swietenia macrophylla, mid-successional species.

scholarly journals Does selective logging affect the leaf structure of a late successional species?

Rodriguésia ◽  
2012 ◽  
Vol 63 (2) ◽  
pp. 419-427 ◽  
Author(s):  
Guilherme Rodrigues Rabelo ◽  
Denise Espellet Klein ◽  
Maura Da Cunha
Keyword(s):  
Leaf Area ◽  
Structural Characteristics ◽  
Selective Logging ◽  
Leaf Structure ◽  
The Sun ◽  
Seasonally Dry ◽  
Sun And Shade Leaves ◽  
Sun And Shade ◽  
Shade Leaves ◽  
Sun Leaves

The anatomical characteristics of both sun and shade leaves of Alseis pickelii were investigated in order to evaluate the consequences of selective logging (in seasonally dry Atlantic Forest) on the leaf structure of this species. Fully expanded sun and shade leaves were collected in two distinct stands of tabuleiro forest; a stand of recently logged forest and an unlogged stand. Only leaves from the unlogged stand revealed significantly different magnitudes of response to light regimes, producing leaves with structural characteristics associated with different levels of irradiance. The sun leaves from this stand had a thicker adaxial surface, mesophyll, palisade and spongy parenchyma, a secondary cell wall of fibers and a lower leaf area compared with the shade leaves. However, in the logged stand, the leaf cuticles of sun and shade leaves showed no significant differences, although the leaf area of the sun leaves was higher than the shade leaves. According to these data, we concluded that the unlogged stand produced typical "sun" and "shade" leaves. In contrast, leaves from the logged stand showed a lower variation of types, where neither typical "sun" nor typical "shade" leaves were produced, suggesting lower leaf plasticity of this late successional tree in this area.

scholarly journals Concentration of photosynthetic pigments and chlorophyll fluorescence of mahogany and tonka bean under two light environments

2001 ◽  
Vol 13 (2) ◽  
pp. 149-157 ◽  
Author(s):  
JOSÉ FRANCISCO DE CARVALHO GONÇALVES ◽  
RICARDO ANTONIO MARENCO ◽  
GIL VIEIRA
Keyword(s):  
Leaf Area ◽  
Photosynthetic Pigments ◽  
Unit Area ◽  
Fresh Mass ◽  
Area Index ◽  
Chl A ◽  
Full Sunlight ◽  
Shade Leaves ◽  
Mass Basis ◽  
Chlorophyll Concentrations

This study was carried out in a plantation of a degraded area in Central Amazon, Brazil, in order to assess environmental light effects on leaf pigment concentrations and chlorophyll a fluorescence in mahogany (Swietenia macrophylla King) and tonka bean (Dipteryx odorata Aubl. Willd). Three-year old saplings were grown in an open site (sun) with maximum radiation of approximately 2000 mumol m-2 s-1 and under the shade of a Ochroma pyramidale (Cav. ex Lam. Urb) canopy. A leaf area index of 2.46 was optically determined for the Ochroma foliage with 13% of full sunlight (maximum radiation about 260 mumol m-2 s-1). Carotenoid and chlorophyll concentrations were spectrophotometrically determined. Initial (Fo), maximum (Fm) and variable fluorescence (Fv) were determined with a portable fluorometer. Chlorophyll concentrations (Chl a, Chl b and Chl tot) on a fresh mass basis were greater in shade leaves than in sun acclimated leaves in both species. On the other hand, when comparisons were made on a per area basis, Chl a concentrations were greater in the sun than in shade leaves of tonka bean. In contrast, Chl b concentrations were higher in the shade environment for this species. No differences were observed in Chl concentrations per unit area in mahogany leaves. Carotenoid concentrations were higher for sun-acclimated leaves of mahogany, both on a per unit area and on a fresh mass basis. In tonka bean, higher carotenoid concentrations in shade leaves were only observed on a fresh weight basis. No differences were found between environments when carotenoid concentrations were expressed as a function of leaf area. Fluorescence variables (Fo, Fm, and Fv) were greater in sun leaves than in shade leaves of mahogany. In contrast, Fv and Fm, but not Fo, values were higher in shade acclimated leaves than in full sunlight-adapted leaves of tonka bean. However, there was a higher Fv/Fm ratio value for tonka bean in sunlight environments. We conclude that these species, classified as mid and late successional species, differ markedly regarding the utilization of photosynthetic pigments, increasing either light harvesting efficiency at low irradiance or protection against photosynthetic machinery damage in higher solar radiation environments.

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.

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.

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