Shade Species Research Articles

Irradiance level and elevation shape the soil microbiome communities of Coffea arabica L.

BackgroundThe nexus plant-microbe-environment is essential to understand the ecosystem processes shaping plant health and fitness. Within this triangle, soils and associated microflora are among the key ecosystem’s drivers, underpinning plant productivity and evolution. In this study, we conducted a comprehensive analysis (physicochemical properties, enzyme activities, and taxonomic diversity) of soils under the canopy projection of Coffea arabica trees along a gradient of elevation (600, 800, and 900 m) and shade (0, 50, 100%).ResultsWhile shade had no influence on most parameters, altitude shaped the dynamics of microbial communities. Available phosphorus, soil organic carbon, and nitrate were significantly higher at 800 m, likely due to the higher activities of β-glucosidase and phosphatases at this altitude. Microbial biomass (carbon and nitrogen) and moisture were significantly higher at 600 and 900 m, which might be attributed to the abundance and richness of soil microorganisms. Indeed, metabarcoding analysis revealed a complex pattern of microbial consortia (bacteria, archaea, fungi) at the three altitudes, with the lowest index of richness recorded at 800 m. The highest number of Amplicon Sequence Variants was observed in bacteria, whose functional analysis revealed distinct metabolic adaptations across different altitudes. At 900 m, the main functional attributes favored the responses to environmental stimuli and microbial interactions; at 800 m, the predominant metabolic pathways were related to organic matter, fermentation, and bioremediation; and at the lower 600 m, the pathways shifted towards the breakdown of plant-derived compounds (e.g. geraniol, limonene, and pinene degradation).ConclusionOverall, the results indicate a higher effectiveness of the microbial consortium at 800 m, which might result in better nutrient cycling. The study highlights the importance of canopy shade species and elevation for the composition of microbial consortia in C. arabica, unveiling ecological functions beyond plant health, with implications for bio-based solutions and biotechnology.

Initial stomatal conductance increases photosynthetic induction of trees leaves more from sunlit than from shaded environments: a meta-analysis.

It has long been held that tree species/leaves from shaded environments show faster rate of photosynthetic induction than species/leaves from sunlit environments, but the evidence so far is conflicting and the underlying mechanisms are still under debate. To address the debate, we compiled a dataset for 87 tree species and compared the initial increasing slope during the first 2-min induction (SA) and stomatal and biochemical characteristics between sun and shade species from the same study, and those between sun and shade leaves within the same species. In 77% of between-species comparisons, the species with high steady-state photosynthetic rate in the high light (Af) exhibited a larger SA than the species with low Af. In 67% within-species comparisons, the sun leaves exhibited a larger SA than the shade leaves. However, in only a few instances did the sun species/leaves more rapidly achieve 50% of full induction, with an even smaller SA, than the shade species/leaves. At both the species and leaf level, SA increased with increasing initial stomatal conductance before induction (gsi). Despite exhibiting reduced intrinsic water-use efficiency in low light, a large SA proportionally enhances photosynthetic carbon gain during the first 2-min induction in the sun species and leaves. Thus, in terms of the increase in absolute rate of photosynthesis, tree species/leaves from sunlit environments display faster photosynthetic induction responses than those from shaded environments. Our results call for re-consideration of contrasting photosynthetic strategies in photosynthetic adaption/acclimation to dynamic light environments across species.

Nutrient Contribution and Carbon Sequestration of an Agroforestry System of Coffea canephora Cultivated by Conventional and Organic Management in the Ecuadorian Amazon

Agroforestry systems (AFSs) seek synergies that improve productivity, sustainability, and environmental benefits. This is achieved through the supplying of nutrients to the soil, carbon storage, and sequestration. In the Ecuadorian Amazon, Coffea canephora is planted together with leguminous, woody, forest, and secondary forest species, where the continuous incorporation of vegetative residues from shade species represents a substantial addition of nutrients within these systems. This study was carried out from 2018 to 2022 to determine the contribution of nutrients contained in the biomass and C sequestration in agroforestry systems of coffee with conventional (high use of agrochemicals) and organic (without the use of chemicals) management. The study was carried out with a randomized complete block design, using a factorial arrangement (2 × 4 with three replications). This arrangement included two types of systems (agroforestry and monoculture) and four agronomic management practices (high and medium for conventional, and intensive and low organic). The biomass and nutrient content were measured twice a year (every 180 days); in addition, the yield was also recorded. A multivariate and univariate analysis was used for data analysis through R and SAS software. After five years of evaluation, it was determined that the N, K, Ca, and Mg contents were higher in the agroforestry systems than the monocultures. In the AFSs, the highest nutrient content was obtained with the medium conventional and low organic agronomic management, while in the monocultures, it was obtained with the high and medium conventional management. In addition, at a soil depth of 20 cm, the total storage and CO2 were 38.12 and 139.8 t ha−1, respectively. The highest yields were obtained with conventional management in AFSs (1599 kg ha−1) and monoculture (1789.45 kg ha−1). Overall, AFSs showed a significant contribution of nutrients, such as N, K, Ca, and Mg, for coffee cultivation; moreover, yields were similar in the AFS and monoculture with both conventional and organic management, which is positive, since AFSs also contribute environmental benefits.

Ethnobotanical Study of Potential Food-Utilization of Shade and Undercover Vegetation in the Coffee Agroforestry Landscape, Kalibaru District, Banyuwangi Regency

Agroforestry is a cultivation system that integrates crops like coffee with various vegetation, as applied in the Kalibaru District. The local community utilizes an agroforestry system by combining shade and undercover plants that can be utilized as food. The objective of this study was to collect a diversity of edible vegetation and investigate the local utilization. Data was collected by vegetation analysis and ethnobotanical studies related to their use. The result showed that 22 species of shade plants and 22 species of undercover plants were edible. The highest use value of shade species in coffee agroforestry are Leucaena leucocephala, Musa paradisiaca, Syzygium aromaticum, Carica papaya, and Artocarpus heterophyllus. Meanwhile, the highest use values in undercover species are Capsicum frutescens, Manihot esculenta, Colocasia esculenta, and Maranta arundinacea. The highest index of cultural significance for shade species is shown in Carica papaya, Leucaena leucocephala, Parkia speciosa, and Musa paradisiaca. Meanwhile, the highest index of cultural significance for undercover species is C. frutescens, L. esculentum, P. amarylifolius, and C. longa. This area can support local food resources and serve as a means of cultural preservation.

Utjecaj ekspozicije krošnje na morfološka svojstva iglica devet četinjača

The aim of this research was to investigate if the crown exposure of some conifers influenced to needle properties. The leaf morphological traits of sixty-six trees of nine conifers: Atlas cedar, Austrian pine, Blue spruce, Douglas fir, European spruce, European yew, Serbian spruce, Silver fir, and White fir, from six Belgrade parks, were analyzed. Five needles were measured from each of the four main crown exposures. Length, width, area and perimeter of needles were investigated. Species, parks in which they were found, as well as crown exposures, differed mostly in needle length and needle width. Correlations between measured needle traits were determined by linear regression analysis. Strong positive correlations were found between the length, perimeter, and area of needles. The differences among the species in terms of light requirement determine species for individual planting as light-loving or partial shade species (Atlas cedar, European spruce, Serbian spruce, Blue spruce, Austrian pine and Douglas fir), or for group planting as shade-loving species (Silver fir, White fir and European yew).

Method for selecting ornamental species for different shading intensity in urban green spaces.

In urban areas, ornamental plants face different constraints, such as the shading of buildings and trees. Therefore, the selection of suitable species and their integration or combination with pre-existing plants is very important. Trees, shrubs, and herbaceous plant species must be distributed according to plant light requirements and shading intensity. Ornamental plants are classified into two groups based on their light intensity or shade tolerance: sun and shade species. To properly position the plants, especially in the immediate vicinity of buildings, it is necessary to study the projection of shadows during the year and the most critical periods, such as July and August. The position of ornamental species with different shading tolerances can be obtained by characterizing the leaf gas exchange for each species. Among the physiological parameters, the most important is the light compensation point, which is the light intensity corresponding to a net photosynthesis equal to zero. This means that the assimilation of carbon dioxide through photosynthesis is equal to the carbon dioxide emitted by respiration. This steady state represents the most critical condition for plants to endure the summer. The distribution of species inside a green area should be determined by considering the minimum light intensity that allows sufficient photosynthesis to compensate for the respiration rate. In this context, non-destructive leaf gas exchange, chlorophyll a fluorescence, and chlorophyll content can be useful tools for selecting suitable ornamental plants under diverse shading conditions.

Differences in ecological resilience of radial growth between Larix principis-rupprechtii and Picea meyeri after drought.

To understand the responses of radial growth to climatic factors and the differences in ecological resilience to drought between a heliophilous species Larix principis-rupprechtii and a shade species Picea meyeri in mixed forests, we developed the tree-ring width chronologies of L. principis-rupprechtii and P. meyeri in three mixed forests based on the samples collected from Toudaogou of Saihanba in Hebei, Ningwu County and Kelan County in Shanxi Province. We analyzed the correlation between climatic factors and various chronologies and examined the differences in resistance (Rc), recovery (Rt), and resilience (Rs) of L. principis-rupprechtii and P. meyeri in response to drought stress. The results showed that the radial growth of L. principis-rupprechtii and P. meyeri was negatively correlated with the mean and maximum air temperature from May to July in three mixed forests, and was positively correlated with the Palmer drought index (PDSI) from May to September. Radial growth decline in trees due to drought stress was significantly different between the two species among the three sites, indicating different physiological and ecological regulation strategies. The resistance of P. meyeri was stronger than that of L. principis-rupprechtii at the three study sites, with stronger resilience and resilient elasticity of L. principis-rupprechtii than P. meyeri. As a result, P. meyeri exhibited greater drought resistance than L. principis-rupprechtii. Under global warming condition, L. principis-rupprechtii might be at greater risk of growth decline than P. meyeri in this region.

Patterns of shade plant diversity in four agroforestry systems across Central America: a meta-analysis

Agroforestry systems can potentially increase tree diversity within agricultural landscapes, but to date, there is little understanding of the patterns of shade plant diversity within different agroforestry systems (AFS) at large spatial scales. Using compiled plant inventory data (from 23 sources, 2517 plots, and 148,255 individuals) encompassing four AFS (shaded coffee; shaded cocoa; dispersed trees on pastures; and live fences) across six countries in Central America we estimated different metrics of diversity to assess the conservation value of different AFS for shade plants. 458 shade plant species were recorded across the four agroforestry systems. Primary forest species accounted for 28% of the shade species recorded, but only 6% of the recorded individuals. No single AFS was consistently the most diverse across countries when considering rarefied species richness. Trees on pastures can potentially reach a similar species richness as cocoa and coffee systems but require sampled areas 7–30 times larger. In terms of composition, 29 species were shared across the agroforestry systems in different countries, illustrating the strong selection pressure of farmers for species that provide timber, firewood, and fruit. Our study highlights the potential contribution and limitations of different AFS for tree diversity conservation within agricultural landscapes.

Shade and no light explain Hovenia dulcis Thunb. invasiveness in subtropical forest fragments: A Greenhouse Microcosm Experiment

Hovenia dulcis is a non-native species with high capacity for invasion in subtropical forest fragments. In this study we used a greenhouse experiment simulating field abiotic and biotic conditions to investigate the germination and growth to determine the mechanisms associated with the high invasion potential of this species. We evaluated the effects of abiotic factors (light) and biotic factors (litter mass and litter type) on ecophysiological parameters: germination (GR), initial establishment (RR and ER) and shoot and root growth in a greenhouse experiment. Interactions between factors were compared using GLM, to select the best model and the factors that influence each parameter evaluated. GR, RR and ER were negative influenced by light intensities, when the low intensity presents more germination and establishment of individuals than intermediate intensity. Additionally, shoot height and root length were negatively influenced by the light intensity with a higher stem elongation in low light intensities. We found no interactions between the abiotic and biotic conditions tested. However, when evaluated individually, germination, establishment and growth were better in low light conditions regardless of the litter mass and litter type. These results challenge the classification of H. dulcis as an intolerant shade species.

Alternative electron transport pathways contribute to tolerance to high light stress in lichenized algae.

The photosynthetic apparatus of lichen photobionts has been well-characterized by chlorophyll fluorescence analysis (e.g., by pulse amplitude modulation [PAM]), which provides a proxy of the activity of photosystem II (PSII) and its antenna. However, such kinetics are unable to directly characterize photosystem I (PSI) activity and the associated alternative electron pathways that may be involved in photoprotection. Instead, PSI can be probed in vivo by near-infrared absorption, measured at the same time as standard chlorophyll fluorescence (e.g., using the WALZ Dual PAM). Here, we used the Dual PAM to investigate cyclic electron flow and photoprotection in a range of mostly temperate lichens sampled from shaded to more open microhabitats. Sun species displayed lower acceptor side limitation of PSI (Y[NA]) early in illumination when compared to shade species, indicative of higher flavodiiron-mediated pseudocyclic electron flow. In response to high irradiance, some lichens accumulate melanin, and Y[NA] was lower and NAD(P)H dehydrogenase (NDH-2)-type cyclic flow was higher in melanised than pale forms. Furthermore, non-photochemical quenching (NPQ) was higher and faster relaxing in shade than sun species, while all lichens displayed high rates of photosynthetic cyclic electron flow. In conclusion, our data suggest that (1) low acceptor side limitation of PSI is important for sun-exposed lichens; (2) NPQ helps shade species tolerate brief exposure to high irradiance; and (3) cyclic electron flow is a prominent feature of lichens regardless of habitat, although NDH-2-type flow is associated with high light acclimation.

Photosynthesis in sun and shade: the surprising importance of far-red photons.

The current definition of photosynthetically active radiation includes only photons from 400 up to 700 nm, despite evidence of the synergistic interaction between far-red photons and shorter-wavelength photons. The synergy between far-red and shorter-wavelength photons has not been studied in sunlight under natural conditions. We used a filter to remove photons above 700 nm to quantify the effects on photosynthesis in diverse species under full sun, medium light intensity and vegetation shade. Far-red photons (701 to 750 nm) in sunlight are used efficiently for photosynthesis. This is especially important for leaves in vegetation shade, where far-red photons can be > 50% of the total incident photons between 400 and 750 nm. Far-red photons accounted for 24-25% of leaf gross photosynthesis (Pgross ) in a C3 and a C4 species when sunlight was filtered through a leaf, and 10-14% of leaf Pgross in a tree and an understory species in deep shade. Accounting for the photosynthetic activity of far-red photons is critical for accurate measurement and modeling of photosynthesis at single leaf, canopy and ecosystem scales. This, in turn, is crucial in understanding crop productivity, the global carbon cycle and climate change impacts on agriculture and ecosystems.

An Assessment of the Hypoglycemic and Antioxidant Properties of the Methanol Extract of Erythrophleum guineense Stem Bark in Albino Rats

ABSTRACT Erythrophleum guineense G. Don is an enormous shade species that is indigenous to moist regions of Africa. Various forms of its bark are used to treat heart diseases, edema, headache, and body pains. In this study, the stem bark of Erythrophleum guineense was subjected to double maceration and extracted with 80% methanol. The methanol extract was screened for its phytochemical components and in vitro antioxidant activity through the utilization of the Ferric Reducing/Antioxidant Power (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity procedures. The acute toxicity of the plant extract was evaluated using Lorke’s method in albino rats. Screening was conducted in normoglycemic and glucose-challenged albino rats to determine the plant extract’s control of blood glucose levels. The doses of the methanol extract of Erythrophleum guineense tested in rats through the oral route were 100, 200, and 400 mg kg−1 body weights of the rats. The effects were compared with glibenclamide (0.2 mg kg−1 per os) and normal saline. The phytochemical constituents of the methanol extract of Erythrophleum guineense were saponins, terpenes, tannins, steroids, carbohydrates, and alkaloids. The results indicated that the plant extract possessed antioxidant and hypoglycemic properties. Further research is warranted to isolate the active hypoglycemic principle of the stem bark of Erythrophleum guineense.

Silvicultural intensification has a limited impact on tree growth in forest restoration plantations in croplands

Investigating the impact of silvicultural practices on tropical forest restoration plantations is highly relevant, as there is a growing global demand for large-scale ecological restoration. The objective of this study was to test the hypothesis that native trees respond positively to the intensification of fertilization and weed control in a forest restoration plantation on a site previously used as cropland in the Atlantic Forest region of Brazil. We carried out a study with 22 native tree species, 11 of which were classified as shade species and the other 11 classified as diversity species. We implemented a randomized experimental design in a split-plot design, with six replicates of four treatments: intensive weed control (glyphosate spraying every 3 months) with and without fertilization, and non-intensive control (mechanical control every 6 months), with and without fertilization. We performed fertilization by supplying the site with 53 kg ha−1 of nitrogen, 35 kg ha−1 of phosphorus, and 51 kg ha−1 of potassium. We evaluated individual tree crown areas and increments in basal diameter and height 16 months after planting. In general, growth varied more among species than in weed control and fertilization treatments. Overall, the method of controlling weeds did not influence tree growth, but interacted with species for all growth variables. Fertilization increased tree diameter increment, and interacted with species, leading to diameter and height increments; however, most of the species did not respond to fertilization. Contrary to our expectations and previous findings, silvicultural intensification did not promote higher overall tree growth, probably because the restoration planting was conducted on a cropland with decades of intensive management, which increased soil fertility and reduced weed abundance through periodical maintenance prior to restoration planting. Our results highlight the importance of considering local and historical conditions to decide whether and when management intensification is required to accelerate tree growth in tropical forest restoration plantations.

Shade lichens are characterized by rapid relaxation of non-photochemical quenching on transition to darkness

AbstractNon-photochemical quenching (NPQ) plays an important role in protecting photosynthetic organisms from photoinhibition by dissipating excess light energy as heat. However, excess NPQ can greatly reduce the quantum yield of photosynthesis at lower light levels. Recently, there has been considerable interest in understanding how plants balance NPQ to ensure optimal productivity in environments in which light levels are rapidly changing. In the present study, chlorophyll fluorescence was used to study the induction and relaxation of non-photochemical quenching (NPQ) in the dark and the induction of photosynthesis in ten species of lichens, five sampled from exposed and five sampled from shaded habitats. Here we show that the main difference between sun and shade lichens is the rate at which NPQ relaxes in the dark, rather than the speed that photosynthesis starts upon illumination. During the first two minutes in the dark, NPQ values in the five sun species declined only by an average of 2%, while by contrast, in shade species the average decline was 40%. For lichens growing in microhabitats where light levels are rapidly changing, rapid relaxation of NPQ may enable their photobionts to use the available light most efficiently.

Evolution of shade tolerance is associated with attenuation of shade avoidance and reduced phenotypic plasticity in North American milkweeds.

Mismatches between light conditions and light-capture strategy can reduce plant performance and prevent colonization of novel habitats. Although light-capture strategies tend to be highly conserved among closely related species, evolutionary transitions from shaded to unshaded habitats (and vice versa) occur in numerous plant lineages. We combined phylogenetic approaches with field and greenhouse experiments to investigate evolutionary constraints on light-capture strategy in North American milkweeds (genus Asclepias) and to determine whether colonization of shaded habitats in this heliophilic clade is associated with reduced plasticity and attenuation of the shade avoidance response. Colonization of shaded habitats has occurred at least 10 times in this genus, including at least once in each major North American clade. Evolutionary transitions between habitats exhibit strong directional bias, with shifts from full-sun to shaded habitats occurring at least three times as often as the opposite transition. In field and greenhouse experiments, sun species responded to shade by increasing internode length, height, and specific leaf area, consistent with the shade avoidance response; paired shade species exhibited reduced plasticity overall, and only one trait (specific leaf area) responded to experimental shade. Our results suggest that milkweeds colonized shaded environments multiple times using a light-capture strategy distinct from the ancestral (putatively shade avoidant) strategy, including a general attenuation of plasticity in response to variable light conditions. This pattern bolsters the notion that shade avoidance and tolerance represent divergent evolutionary strategies for maximizing performance under qualitatively different types of shade.

Apparent nitrogen limitation of Robusta coffee yields in young agroforestry systems

AbstractRobusta coffee (Coffea canephora Pierre ex Froehner) is an important cash crop in the lowland tropics. Similar to Arabica (C. arabica L.), agroforestry is common in these systems, though comparatively little is known about how nutrient inputs and leguminous shade trees influence Robusta nutritional status and yield. We evaluated how shading with leguminous trees across four input systems, defined largely by quantity and form (compost vs. synthetic) of nitrogen (N), phosphorus (P), and potassium (K), influenced Robusta‐based cropping systems in the Ecuadorian Amazon. Soil fertility was largely unaffected by compost and synthetic fertilizer (NPK) inputs or by shade species, and was weakly related to coffee productivity based on principal component analysis (PCA). Though litter appeared to be an agronomically appreciable source of N and P, this was only somewhat reflected in soil extractable N and P, presumably due to nutrient losses under high rainfall conditions (>3,000 mm yr−1). Patterns of variation suggest transfer of N and P from litter to soil to leaf. Conversely, litter K was unrelated to soil K, but soil K was closely related to leaf K. Robusta yields appeared to be largely N limited and were more influenced by input type (i.e., synthetic vs. organic nutrient sources) than by shade species or amount of N inputs in the form of compost or synthetic N, P, and K fertilizers. Additionally, yields across all treatments were significantly higher than regional averages, suggesting that slight investments in inputs can substantially increase productivity in maturing Robusta systems, irrespective of shade tree species selection.

Cuantificación de la fijación biológica del nitrógeno en árboles de sombra de dos cafetales de Cuba

In coffee agroecosystems, it is of much importance to maintain appropriate levels of nitrogen to guarantee stable and sustainable productions. In this agriculture type, it is fundamental to consider the insert of shade species that carry out the Biological Fixation of the Nitrogen like natural form of incorporating this element to the soil. In that sense, it was carried out an experiment in two coffee areas ( Coffea canephora var. Robusta) of the East of Cuba, in Sagua-Nipe-Baracoa and Sierra Maestra mountains, with the objective of quantifying the production of dry biomass and content of two leguminous used as shade trees ( Samanea saman and Gliricidia sepium ) and starting, from those determinations, to estimate the nitrogen biological fixation by the total N difference method. The dry mass and N content quantified in the shade trees were superior to the valued in the coffee, due to the different behavior among the species in study, coffee dry mass oscillated between 1.23 and 1.75 t ha -1 and the shade trees between 2 and 3 t ha -1 . The contents of foliate N of the shade species oscillated among 25-40 kg ha -1 and the coffee presented foliar concentrations of the element in appropriate ranges. The arboreal species present BFN between 20 and 55 %, that which transforms them into an important source for the contribution and recycling of the nitrogen inside the coffee ecosystems.

Investigation of Shade Tree Species Used in Tea Garden in Bangladesh

The shade trees are an integral component of tea cultivation in Bangladesh. The shade trees are essential for modulating the environment of the tea ecosystem, enriching the soil fertility, reducing temperature and the evaporative capacity, conserve soil moisture and helps in the control of certain pests and diseases which are positively thermotropic in nature. The shade trees provide partial shade to the tea plants, which is important for improving the quality of the tea leaf. The right type of shade trees and their proper management is a prerequisite for successful tea crop growing. For this persists, a floristic exploration of shade trees was carried out at fifteen tea gardens in Chattogram and Moulvibazar District of Bangladesh from November 2017 to December 2018. During the investigation, a total of 44 species of Angiosperm representing 31 genera of 9 families was enlisted. For every species, scientific name, vernacular name, status, and necessary photographs are mentioned. In the assessment, the Fabaceae family shows the highest number of shade trees comprising 19 genera and 31 species. The most common permanent shade tree species among the tea gardens are Albizia odoratissima, A. chinensis, A. lebbeck, A. lucidior, A. procera, and Derris robusta. Indigofera teysmannii is frequently using as a temporary shade species in all investigated tea gardens. Cajanus cajan, Tephrosia candida, Tephrosia candida, Gliricidia sepium, Erythrina lithosperma and Desmodium gyroides species are also used as temporary shade trees in many tea gardens. Further investigations, however,are required to find out the right type of shade tree species on the growth and yield of tea plants in tea cultivation areas of Bangladesh.
 SAARC J. Agri., 18(1): 219-237 (2020)

Spectral quality of monochromatic LED affects photosynthetic acclimation to high-intensity sunlight of Chrysanthemum and Spathiphyllum.

Vertical farming using light-emitting diode offers potential for the early production phase (few weeks) of young ornamental plants. However, once transferred to the greenhouse, the photosynthetic acclimation of these young plants might depend on this initial light regime. To obtain insight about this acclimatization, Chrysanthemum (sun species) and Spathiphyllum (shade species) were preconditioned in growth chambers for 4 weeks under four light qualities: blue (B), red (R), red/blue (RB, 60% R) and white (W) at 100 μmol m-2 s-1 . Monochromatic light (R and B) limited leaf development of both species, which resulted in a lower leaf mass per area when compared to multispectral light (RB for Chrysanthemum, RB and W for Spathiphyllum). R-developed leaves had a lower photosynthetic efficiency in both species. After the light quality pretreatment, plants were transferred to the greenhouse with high-intensity natural light conditions. On the first day of transfer, R and B preconditioned leaves of both species had an inhibited photosynthesis. After 1 week in natural light condition, rapid light curve parameters of Chrysanthemum leaves that developed under B acclimated to sunlight had a similar level than RB-developed leaves unlike R-leaves. Spathiphyllum leaves showed a decrease in maximum electron transport rate and this was most pronounced for the R pretreatment. After 1 month, R-preconditioned Chrysanthemum had the lowest dry mass, while no effects on the dry weight of Spathiphyllum with respect to the pretreatments were observed. Light quality during preconditioning affected the leaf ability to acclimate to natural high light intensities in greenhouse environment.

Shade tree timber as a source of income diversification in agroforestry coffee plantations, Peru

Coffee is traditionally grown in agroforestry systems. Shade trees in coffee plantations provide important ecosystem services, and their timber may also be a good source of income for coffee growers. However, key information on the value of shade tree timber and its potential contribution to the income of coffee growers based on empirical data is lacking. The income that could be obtained from shade trees was estimated for three coffee plantations with different shade tree species. To estimate the marketable timber volume of standing trees, allometric equations were developed. Our results showed that the value of the shade tree timber varied significantly. It represented only 2-3% of the annual coffee farm income on the coffee plantation dominated by native Inga spp. On the other hand, the plantation predominantly shaded by Eucalyptus trees had high potential annual (50-68% of plantation income) and total (92-96% of plantation income) timber value, followed by the plantation shaded predominantly by Pinus (32-49% of plantation income for annual timber volume and 89-94% of plantation income for total timber volume). It is evident that shade trees may be a good economic reserve for coffee growers when exotic Eucalyptus or Pinus tree species are planted. However, using individual-tree data, it was found that the relatively rare native shade tree Retrophyllum rospigliosii, which was found in almost all plantations, has a high timber value and a large timber supply, making it a shade species with high potential for agroforestry.