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 Leaf and Crown Optical Properties of Five Early-, Mid- and Late-Successional Temperate Tree Species and Their Relation to Sapling Light Demand

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 925 ◽  
Author(s):  
Marc Hagemeier ◽  
Christoph Leuschner
Keyword(s):  
Optical Properties ◽  
Leaf Area ◽  
Tree Species ◽  
Forest Floor ◽  
The Sun ◽  
Area Index ◽  
Minimum Light ◽  
Tree Canopies ◽  
Successional Species ◽  
Shade Leaves

The optical properties of leaves and canopies determine the availability of radiation for photosynthesis and the penetration of light through tree canopies. How leaf absorptance, reflectance and transmittance and radiation transmission through tree canopies change with forest succession is not well understood. We measured the leaf optical properties in the photosynthetically active radiation (PAR) range of five Central European early-, mid- and late-successional temperate broadleaf tree species and studied the minimum light demand of the lowermost shade leaves and of the species’ offspring. Leaf absorptance in the 350–720 nm range varied between c. 70% and 77% in the crown of all five species with only a minor variation from the sun to the shade crown and between species. However, specific absorptance (absorptance normalized by mass per leaf area) increased about threefold from sun to shade leaves with decreasing leaf mass area (LMA) in the late-successional species (Carpinus betulus L., Tilia cordata Mill., Fagus sylvatica L.), while it was generally lower in the early- to mid-successional species (Betula pendula Roth, Quercus petraea (Matt.)Liebl.), where it changed only a little from sun to shade crown. Due to a significant increase in leaf area index, canopy PAR transmittance to the forest floor decreased from early- to late-successional species from ~15% to 1%–3% of incident PAR, linked to a decrease in the minimum light demand of the lowermost shade leaves (from ~20 to 1%–2%) and of the species’ saplings (from ~20 to 3%–4%). The median light intensity on the forest floor under a closed canopy was in all species lower than the saplings’ minimum light demand. We conclude that the optical properties of the sun leaves are very similar among early-, mid- and late-successional tree species, while the shade leaves of these groups differ not only morphologically, but also in terms of the resource investment needed to achieve high PAR absorptance.

Agronomic Performance of New Potato Genotypes Submitted to Increasing Doses of NPK

2019 ◽  
pp. 1-10
Author(s):  
Keli Cristina Dos Santos ◽  
Gentil Carneiro Gabardo ◽  
Jackson Kawakami ◽  
Aline Genú ◽  
Sara Passos ◽  
...  
Keyword(s):  
Leaf Area ◽  
Light Absorption ◽  
Morphological Characteristics ◽  
Fresh Mass ◽  
Tuber Number ◽  
Productive Capacity ◽  
Area Index ◽  
Growing Seasons ◽  
Significant Difference ◽  
Npk Fertilizer

Aims: Estimate the morphological characteristics of potato genotypes grown with different doses of NPK fertilizer 4-14-8. Study Design: The experiment was conducted in randomized blocks with subdivided plots and three replicates. Place and Duration of Study: The experiment was carried out in the municipality of Guarapuava – PR, Brazil, during the growing seasons of 2013/2014 and 2014/2015. Methodology: In the main plots the doses of 0, 2, 4 and 6 t ha-1 of NPK fertilizer 4-14-8 were arranged and in the subplots the genotypes (Ágata, BRS Camilla and clone C0205). Were evaluated: The leaf area index (LAI), percentage of light absorption, number of tubers, fresh mass of tubers. In the first agricultural year the evaluations were performed at 25 and 45 days after the emergency (DAE) and in the second seasson at 28 and 48 DAE. Interaction between potato genotypes and fertilizer rates for LAI was observed at 45 DAE in 2013/14 and absorbance at 25 DAE in 2013/14. For the seasson 2013/14, the genotypes showed a significant difference for LAI, absorbance, number of tubers and fresh mass of tubers at 25, LAI and fresh mass of tubers at 45 DAE, clone C0205 presented the largest differences for these characteristics. Fertilizer doses did not influence LAI, absorbance at 25 DAE and 45 DAE in 2013/14 and, at 2014/15 at 28 DAE, there was no response for tuber number and LAI, and at 48 DAE for tuber number, absorbance. There was no significant interaction between fertilizer doses and potato plant genotypes for the data on number of primary stems and number of secondary stems in both seassons The genotypes responded to NPK fertilizer doses 4-14-8 for LAI, and clone C0205 presented the best results. The genotypes responded to the light absorption percentage, with C0205 presenting the best results, so that plants with greater leaf area presented greater light absorption. The genotype C0205 presents greater productive capacity when compared to the Agata and Camila genotypes, being evident the greater number and fresh mass of tubers produced.

scholarly journals Development of the leaf area and the productivity structure of the sunflower hybrids in the north-eastern Forest-Steppe of Ukraine

2019 ◽  
pp. 33-39
Author(s):  
М.М. Sakhoshko ◽  
M.I. Kravchenko ◽  
V.M. Yatsenko ◽  
I.O. Kolosok
Keyword(s):  
Leaf Area ◽  
Field Experiments ◽  
Unit Area ◽  
Geographical Area ◽  
Main Element ◽  
Forest Steppe ◽  
Area Index ◽  
The North ◽  
North Eastern ◽  
Sunflower Crop

At the present stage, the model of leaf plant development is increasingly considered as the main element of genotypes adaptation to specific cultivation conditions, geographical area, etc. Under these conditions, the potential of the hybrid, the range of its adaptation to environmental conditions is determined by the level of interaction between the development of the assimilation apparatus and the generative organs. An urgent task aimed at improving the productivity of sunflower crop due to the use of genotypes adapted to the conditions of the north-eastern Forest-Steppe and Polyssya of Ukraine is to identify typical schemes of interaction of photosynthetic potential and parameters of plant productivity and crop yields. The studies were conducted in accordance with the program for the development of a variety model for the conditions of the north-eastern Forest-Steppe and Polyssya of Ukraine. Field experiments were carried out in 2016‒2019 at the Sumy National Agrarian University and the Institute of the Agriculture of North East of Ukraine. In the studies, 28‒56 hybrids of different originators were tested annually. Sunflower was cultivated according to the technology recommended for the area, with pre-harvesting density of 60 thousand plants / ha. Harvesting was done manually, from two central rows of a 4-rows plot. The results were processed using the Statistics package. The data on yield indices and values of leaf area coefficient (LAC) of crop for groups of varieties separated by the duration of growing season were analyzed. It was found that the increasing of leaf area was accompanied by an increasing of yield in case of comparing groups with dates of technological maturation until 20 August, 1 September and 10 September. In all cases, the maximum value of the leaf area index ranged from 3.12‒3.52 m2/m2. These dynamics of indicators indicated to the regulatory nature of the values of leaf area coefficient (LAC) of modern sunflower crop and the absence of genotypes (or conditions) capable of maintaining these values at the level of more than 3.3‒3.5 m2/m2. According to the analysis of correlation pleiades, the presence of several levels was found and the relative independence of the relationships between the group of parameters, determining the morphological structure of plants and the vertical structure of crop and the group of parameters, characterizing the content of chlorophyll and its concentration per unit area of leaf surface. In practical terms, the results of the analysis indicated the potential informative nature of the complex use of parameters characterizing the morpho-structure of plants, primarily the index of leaf area and the index of chlorophyll concentration per unit area. In order to isolate the typical schemes characteristic of different levels of adaptation to the conditions of the zone, data on 29 sunflower hybrids distributed in the region were clustered. The results of the analysis allowed to distinguish three significantly different algorithms for the realization of the vegetative and generative potential of sunflower hybrids in the area of the north-eastern Forest-Steppe of Ukraine. It has been established that one of the factors for successful realization of the generative potential of sunflower hybrids in the conditions of the zone is the ability to preserve and (in some cases) to improve the structure of relations between the dynamics and parameters of the plant leaf apparatus and the parameters of their generative development.

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.

Leaf heteroblasty in eucalypts: biogeographic evidence of ecological function

2018 ◽  
Vol 66 (3) ◽  
pp. 191 ◽  
Author(s):  
Carolyn Vlasveld ◽  
Benjamin O'Leary ◽  
Frank Udovicic ◽  
Martin Burd
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Unit Area ◽  
Leaf Shape ◽  
Eucalyptus Species ◽  
Canopy Closure ◽  
Area Index ◽  
Leaf Mass ◽  
Adult Leaf ◽  
Shape And Size

Leaves that develop on seedlings, young saplings or regenerative shoots of many eucalypt species are strikingly different in morphology from the typical leaves of more mature plants; a developmental pattern known as heteroblasty. We measured dimorphism between juvenile and adult leaves in shape and size, leaf mass per unit area, and vein frequency in a continent-wide sample of Angophora, Corymbia and Eucalyptus species. We tested whether heteroblasty in this group is an adaptation to shading by comparing the degree of juvenile–adult leaf dimorphism with the canopy closure (measured by the leaf area index) of the habitat in which species occurred. No pattern emerged for heteroblasty in leaf shape and size or leaf mass per unit area, but there was a significant relationship (accounting for phylogenetic relationships) between the degree of juvenile–adult dimorphism in vein frequency and habitat leaf area index. Juvenile leaves tended to have more widely spaced veins than adult leaves of the same species, in regions with more closed vegetative canopies. This evidence suggests that eucalypt heteroblasty is, at least in part, a hydraulic adaptation to the different conditions faced by younger and older plants in higher productivity regions with denser vegetation.

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 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.

Effects of shading on the growth and nitrogen content of green panic and Siratro in pure and mixed swards defoliated at two frequencies

1980 ◽  
Vol 31 (2) ◽  
pp. 269 ◽  
Author(s):  
CC Wong ◽  
JR Wilson
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Nitrogen Fertilizer ◽  
Light Extinction ◽  
Panicum Maximum ◽  
Nitrogen Accumulation ◽  
Nitrogen Status ◽  
Area Index ◽  
Full Sunlight ◽  
Nitrogen Yield

A study was made of the effect of illumination at 100, 60 and 40% of sunlight on the growth of Macroptilium atropurpureum cv. Siratro and Panicum maximum var. trichoglume cv. Petrie (green panic) in pure and 50150 mixture swards, dcfoliated every 4 (D4) 01 8 (D8) weeks. The plants were grown without nitrogen fertilizer on a soil of moderate nitrogen status. Shading to 60 and 40% of full sunlight increased the shoot yield of green panic in pure sward by 30 and 27% respectively in the D8, but reduced it in the D4 treatment by 3 and 14%. Shade (40% full sunlight) reduced the shoot yield of Siratro in pure swards by 38 and 33 % in the D4 and D8 treatments. Nitrogen accumulation in green panic was markedly improved by shading: the increase in shoot nitrogen yield in pure sward under 60 and 40% light levels was 29 and 32% for the D4 and 45 and 76 % for the D8 treatment. All plant fractions of green panic increased in percentage nitrogen with increasing shade. The nitrogen yield of Siratro in pure sward declined with shading in proportion to dry weight. Shaded green panic swards had a higher leaf area index, better distribution of leaf area with height, and lower light extinction coefficients. The individual leaves had greater photosynthetic activity than those from the full sunlight swards. Shade-grown Siratro swards had a lower leaf area index and their leaves had a lower photosynthetic potential than in the full sunlight treatment. Nodulation was reduced under shade. Competition between green panic and Siratro was most severe in relation to shoot yield, and was accentuated by shading, frequent defoliation, and time. The proportion of Siratro in the mixture declined from 40 % initially to as low as 4-6 %. The extra competitiveness of the tropical grass, green panic, under shade in this experiment was due to a substantially increased ability to accumulate nitrogen and also to changes in canopy structure. In soils of markedly different nitrogen status or with nitrogen fertilizer the shade response might be modified.

The effects of seed size and spacing on growth and yield of lesser yam (Dioscorea esculenta)

1972 ◽  
Vol 78 (2) ◽  
pp. 215-225 ◽  
Author(s):  
B. A. C. Enyi
Keyword(s):  
Leaf Area ◽  
Seed Size ◽  
Dry Matter ◽  
Unit Area ◽  
Tuber Initiation ◽  
Area Index ◽  
Spacing Distance ◽  
Leaf Area Duration ◽  
Growth Development ◽  
Bulking Rate

SUMMARYThe effects of seed size and spacing on growth, development and yield of lesser yam and the relationship between growth, development and yield in this yam variety were investigated in the 1967 and 1968 growing seasons. Larger seeds outyielded smaller ones both in the total and ware tuber yields. The seed size effect was associated with a difference in tuber number, leaf area duration and bulking rate. Mean tuber weight at harvest, decreased with the decrease in seed size. Total and ware tuber yields increased with the decrease in spacing distance. The spacing effect was associated with differences in leaf area duration and bulking rate per unit area. Final total dry matter produced per plant increased with the increase in both seed size and spacing distance but the dry matter produced per unit area decreased with the increase in spacing distance. Leaf area index and leaf area duration increased with an increase in seed size and decreased with increase in spacing distance. There was a greater positive relationship between total tuber yield and leaf area duration between tuber initiation and the final sampling period than that between it and absolute leaf area duration.

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.

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