High Shade Research Articles

환경정화용 녹색식물소재로서 자생 맥문동의 중금속 축적 및 토양 내 제거 특징

This study attempted to utilize various groundcover plants in phytoremediation, using shade plants, which often have a high shade tolerance for shade urban space. Liriope platyphylla was grown in soil containing three of heavy metals, Zn, Cd, and Pb under four different concentrations (0, 100, 250 and 500 mg/kg) to determine the heavy metal accumulation characteristics and removing from soil. Total amounts of accumulated Zn in L. platyphylla were increased in accordance with increasing elevated Zn concentrations in soil, but the difference was not significant between Zn250 and Zn500. Cd accumulation, sharply increased in Cd100 and Cd250, but was reduced in Cd500. Increased Pb concentration in soil resulted a continuous increase in the total amounts of Pb accumulated in L. platyphylla. The total content of Zn in soil decreased by almost 50% in Zn100, almost 33% in Zn250 and 20% in Zn500 through growth of L. platyphylla over a period of 7 months. In the case of Cd, the concentration in soil, was decreased with 10% in Cd100, 10% in Cd250 and 33% in Cd500 through growth of L. platyphylla over a period of 7 months. This results indicate that more Cd was removed by planting L. platyphylla, compared to Zn or Pb.

Lateglacial studies in the western valleys of the Italian Julian Alps and in the Koritnica valley

Different from the northern valleys of the Italian Julian Alps the bottoms of the western valleys do not contain any late-pleistocene moraines. However, common to all valleys is the large glaciation most probably in the Gschnitz-stage, in which the glaciers reached particularly low locations due to special favourable aspects such as north-exposure, steep and narrow gorges, high shading and considerable snow accumulation. This is also valid for the sidebranches of the Slovenian Koritnica valley which are again directed west-east. Still younger glacier stages could be found in the upper sections of the Dogna, Raccolana and Bala valley. For the moraines of very low altitudes in the Resia valley, at the entrance to Možnica and the upper Raccolana valley pollen analyses are available. All considerations in the paper are estimations based on geomorphological and climatological experience.

Changes in plant species density in an experimentally fragmented forest landscape: Are the effects scale-dependent?

The establishment of commercial tree plantations is a common cause of habitat fragmentation globally, yet the influence of this land use on plant species density in fragmented native forests requires further understanding. Theory predicts species density will be highest in large areas of habitat, and should decline as area is reduced, but whether these effects are scale-dependent is largely unknown. We assessed plant species density (total, common and uncommon species) in experimentally fragmented eucalypt forest remnants (0.25, 0.88, 3.06 ha) surrounded by a pine plantation, at three spatial scales using nested quadrats. Specifically, we consider how plant species density varies across three different sized fragments, and whether the response of species density is magnified in common or uncommon species. Species density in small fragments was higher than continuous forest for all species groupings at the smallest spatial scale (1 m2), and for total and common species at the next smallest spatial scale (16 m2). No species groupings responded to reductions in habitat area at the largest spatial scale (144 m2). We suggest that pine plantations may cause higher species density in small fragments via two mechanisms, either by allowing species to infill unoccupied areas within small fragments, or by buffering small fragments from species losses during a severe and prolonged drought. In both cases we suspect reduced moisture stress (e.g. increased soil moisture, higher shading and reduced temperature) in small fragments has led to the observed changes in species density.

Developing a weather responsive internal shading system for atrium spaces of a commercial building in tropical climates

In response to the non-trivial problem of overheating in glass roofed buildings in low latitudes a study was undertaken to reduce discomfort and high energy consumption in a large atrium building in China. This paper reports on the development of a shading system designed for that building as a remedial solution to reduce temperatures while maintaining adequate levels of natural lighting in the atrium spaces of a large multifunctional commercial building. The effects of the shading system on both the physical indoor environment and its economic implications were analysed using implemented models. Calibrated with the data measured in the building during the hottest season, summer, the models were used to test both thermal and lighting performance of two shading arrangements: high and low level blinds in both open and covered modes on typical overcast days and clear days in summer and winter respectively. Also tested were two types of fabric used for the blinds.The performance of these tested cases was assessed for solar gain, cooling loads, internal surface temperatures, air temperatures and operative temperatures of both ground floor and surrounding walkways on various levels within the atrium, the major circulation areas. The results reveal that the high level shading, with blinds fixed close to the glazed roof are generally less effective in the provision of thermal and lighting conditions of the atrium, than the low level shading, where blinds are fixed 3–5 m below the glazed roof to form a ventilated void. The financial benefits of these remedial solutions were also assessed using standard economic analysis methods to provide recommendations on their costs and payback periods.

Whole‐plant trait spectra of North American woody plant species reflect fundamental ecological strategies

The adaptation of plant species to their biotic and abiotic environment is manifested in their traits. Suites of correlated functional traits may reflect fundamental tradeoffs and general plant strategies and hence represent trait spectra along which plant species can vary according to their respective strategies. However, the functional interpretation of these trait spectra requires the inspection of their relation to plant performance. We employed principle coordinate analysis (PCoA) to quantify fundamental whole‐plant trait spectra based on 23 traits for 305 North American woody species that span boreal to subtropical climates. We related the major axes of PCoA to five measures of plant performance (i.e., growth rate, and tolerance to drought, shade, water‐logging and fire) for all species and separately for gymnosperms and angiosperms. Across all species a unified gymnosperm‐angiosperm trait spectrum (wood density, seed mass, rooting habit) is identified, which is correlated with drought tolerance. Apart from this, leaf type and specific leaf area (SLA) strongly separate gymnosperms from angiosperms. For gymnosperms, one trait spectrum emerges (seed mass, rooting habit), which is positively correlated with drought tolerance and inversely with shade tolerance, reflecting a tradeoff between these two strategies due to opposing trait characteristics. Angiosperms are functionally more diverse. The trait spectra related to drought tolerance and shade tolerance are decoupled and three distinct strategies emerge: high drought tolerance (low SLA, dense wood, heavy seeds, taproot), high shade tolerance (high SLA, shallow roots, high toxicity, opposite arranged leaves), and fast growth/stress intolerance (large maximum heights, soft wood, light seeds, high seed spread rate). In summary, our approach reveals that complex suits of traits and potential tradeoffs underlie fundamental performance strategies in forests. Studies relying on small sets of plant traits may not be able to reveal such underlying strategies.

Population dynamics of canopy trees in New Caledonian rain forests: are monodominantNothofagus(Nothofagaceae) forests successional to mixed rain forests?

Abstract:In New Caledonia, rain forests with an upper canopy dominated by single species ofNothofagusoccur next to mixed-canopy forests, without discernible environmental cause. A potential explanation is that they are different successional stages. To test this hypothesis and predict long-term change in canopy dominance, population size structures of 61 canopy species were analysed in sixNothofagus-dominated forests and three adjacent mixed rain forests. Weibull analysis suggests that theseNothofagusforests are secondary forests, with recruitment insufficient to maintain monodominance, except at a high-altitude site. At low- to mid-altitudes theNothofaguscanopy is predicted to develop into a mixed canopy, unless moderate to severe disturbance occurs within its reproductive lifespan. However, adjacent mixed rain forests are also secondary, with 85% of analysed species showing no evidence of continuous regeneration. Fifteen species from both forest types showed reverse-J curves suggesting continuous regeneration, but onlyCalophyllum caledonicumdid so consistently. Since few canopy species showed evidence of high shade tolerance and persistence, a small number of shade-tolerant species is predicted to dominate both forests in the long term, in the hypothetical absence of disturbance. Hence, temporal factors associated with disturbances play a key role in determining dominance in these forests.

Indirect Effects of a Fungal Entomopathogen,Lecanicillium lecanii(Hypocreales: Clavicipitaceae), on a Coffee Agroecosystem Ant Community

Fungal entomopathogens are widely distributed across natural and managed systems, with numerous host species and likely a wide range of community impacts. While the potential for fungal pathogens to provide biological control has been explored in some detail, less is known about their community interactions. Here we investigate the effects of fungal epizootics of the entomopathogen Lecanicillium lecanii (Zimmerman) on a keystone mutualism between Azteca instabilis (F. Smith), a dominant arboreal ant, and the green coffee scale (Coccus viridis Green), as well as broader impacts on a coffee agroecosystem ant community. We hypothesized that seasonal epizootics cause shifts in the foraging ranges of A. instabilis as the ants adapt to the loss of the resource. We further hypothesized that the magnitude of these shifts depends on the availability of alternate resources located in neighboring shade trees. To test these hypotheses, we induced an epizootic in experimental sites, which were compared with control sites. Surveys of ant activity were undertaken pre- and post-epizootic. We found a decrease in foraging activity of A. instabilis and increase in activity of other ant species in the experimental sites post-epizootic. The decrease in abundance of A. instabilis foragers was greater on plants in which an epizootic was induced than in other plants. This relationship was modified by shade tree density where higher shade tree density was associated with larger decreases in A. intabilis foraging activity in coffee plants. These results demonstrate the potential for fungal entomopathogens to influence the structure and diversity of ecological communities.

Thematic and Spatial Resolutions Affect Model-Based Predictions of Tree Species Distribution

Subjective decisions of thematic and spatial resolutions in characterizing environmental heterogeneity may affect the characterizations of spatial pattern and the simulation of occurrence and rate of ecological processes, and in turn, model-based tree species distribution. Thus, this study quantified the importance of thematic and spatial resolutions, and their interaction in predictions of tree species distribution (quantified by species abundance). We investigated how model-predicted species abundances changed and whether tree species with different ecological traits (e.g., seed dispersal distance, competitive capacity) had different responses to varying thematic and spatial resolutions. We used the LANDIS forest landscape model to predict tree species distribution at the landscape scale and designed a series of scenarios with different thematic (different numbers of land types) and spatial resolutions combinations, and then statistically examined the differences of species abundance among these scenarios. Results showed that both thematic and spatial resolutions affected model-based predictions of species distribution, but thematic resolution had a greater effect. Species ecological traits affected the predictions. For species with moderate dispersal distance and relatively abundant seed sources, predicted abundance increased as thematic resolution increased. However, for species with long seeding distance or high shade tolerance, thematic resolution had an inverse effect on predicted abundance. When seed sources and dispersal distance were not limiting, the predicted species abundance increased with spatial resolution and vice versa. Results from this study may provide insights into the choice of thematic and spatial resolutions for model-based predictions of tree species distribution.

Review of Advanced Daylighting Systems

Daylight is the most underutilized resource in modern buildings. Artificial light can be dispensed away in institutional buildings such as offices, banks, schools etc. having only daytime occupancy by proper architectural design of fenestrations The design of a day lighting space is both an art and a science. The biggest challenge facing the lighting designer is to admit only as much light as necessary and distribute it evenly throughout the space without introducing glare or heat. In hot / warm climates, it has become common practice in windows spaces to specify blinds and glazing with high shading coefficients to control glare and minimize heat gain. However, this practice reduces the effectiveness of lighting systems that dim automatically. Improved systems are needed to capture natural daylight and distribute it uniformly throughout a space while controlling heat gain and glare. One such system is the light shelf. Light shelves shade the space from direct sunlight and reflect this sunlight onto the ceiling for a deeper and more uniform distribution. Reflective blinds offer good control of glare and solar protection. Innovative day lighting systems are designed to redirect sunlight or sky light to areas where it is needed with excessive luminance and glare. These systems use optical devices that initiate reflections, refractions, and / or use total internal reflection of sunlight and sky light. Advanced day lighting systems can be designed to actively track the sun or passively control the direct sunlight and sky light. In this paper, we review the state of the art of several advanced day lighting systems which are designed to maximize the energy-saving potential of day lighting, while improving comfort and visual performance at an “affordable” cost.

Interactive effects among ecosystem services and management practices on crop production: Pollination in coffee agroforestry systems

Crop productivity is improved by ecosystem services, including pollination, but this should be set in the context of trade-offs among multiple management practices. We investigated the impact of pollination services on coffee production, considering variation in fertilization, irrigation, shade cover, and environmental variables such as rainfall (which stimulates coffee flowering across all plantations), soil pH, and nitrogen availability. After accounting for management interventions, bee abundance improved coffee production (number of berries harvested). Some management interventions, such as irrigation, used once to trigger asynchronous flowering, dramatically increased bee abundance at coffee trees. Others, such as the extent and type of tree cover, revealed interacting effects on pollination and, ultimately, crop production. The effects of management interventions, notably irrigation and addition of lime, had, however, far more substantial positive effects on coffee production than tree cover. These results suggest that pollination services matter, but managing the asynchrony of flowering was a more effective tool for securing good pollination than maintaining high shade tree densities as pollinator habitat. Complex interactions across farm and landscape scales, including both management practices and environmental conditions, shape pollination outcomes. Effective production systems therefore require the integrated consideration of management practices in the context of the surrounding habitat structure. This paper points toward a more strategic use of ecosystem services in agricultural systems, where ecosystem services are shaped by the coupling of management interventions and environmental variables.

Shade tolerance of temperate Asian bamboos: a harbinger of their naturalization in Pacific Northwest coniferous forests?

Bamboos native to temperate East Asian coniferous forests arrive with increasing frequency in the United States as horticultural imports, and some are becoming naturalized locally. Given the strong floristic and physiognomic similarities between East Asian and western North American coniferous forests, we asked whether these introduced bamboos could tolerate the varied light regimes within coniferous forests in their new range. Seven temperate Asian bamboos and one North American bamboo (Arundinaria gigantea) were grown within shade structures in an experimental garden; these structures reduced ambient light to three light levels (50, 70, 90 % shade) that occur routinely within coniferous forests in the Pacific Northwest. Species’ responses under these light levels were measured by their light response curves to photosynthesis, resource allocation to light or carbon harvesting centers inferred by CO2 response curves, and shifts amongst forms of leaf Chlorophyll. Bashania fargesii has lower chlorophyll content and photosynthetic rates under high shade (90 %) relative to other Asian species and to B. fargesii grown in 50 and 70 % shade. Bashania fargesii, Sasa kurilensis and A. gigantea also displayed lower photosynthetic rates under 90 % shade compared to plants grown in 50 and 70 % shade and lower electron transport capacity under 70 and 90 % shade compared to plants grown in 50 % shade. In contrast, Pleioblastus chino, Pleioblastus distichus, Pseudosasa japonica, Sasa palmata and Sasaella ramosa display strong tolerance of low light. Our results indicate these five Asian bamboos (and others yet to be introduced) could skirt a major environmental barrier to new species establishment in these North American forests. Measuring a species’ light response curve offers a reliable, rapid means to assess an immigrant species’ potential to tolerate forests’ varied light regimes.

Does shade cover availability limit nest-site choice in two populations of a turtle with temperature-dependent sex determination?

Shifts in resource use may be an important mechanism by which organisms can adjust to novel environmental conditions, such as those imposed by climate change. However, for such shifts to be possible, environmental space must exist into which organisms can move. Habitat that ensures successful survival and reproduction is one such critical resource. We studied resource selection of shade cover over nest sites by painted turtles in populations in Illinois (center of range) and New Mexico (southern edge of range). We targeted this habitat feature because shade can influence hatching success and offspring phenotype (including sex in the study species) by affecting nest microenvironments. We found that while turtles in both populations selected nest sites that were shadier than average available sites, overall resource selection differed between the populations. This disparity may have been due to differences in structure of vegetation that provides shade at each site, because areas with high shade cover in New Mexico (low dense thickets) were much more difficult for turtles to access than those in Illinois (dense tree canopy cover). Further, shade cover predicted different parameters of incubation regime at each site, suggesting that turtles must assess dissimilar components of shade cover in order to choose nest sites and predict their future incubation regimes. Our results suggest that shade cover within nesting areas is a key component of painted turtle habitat, and that accessible, highly-shaded nest sites may be limited at the New Mexico site. Maintaining a range of shade cover from which turtles can select nest sites would permit plasticity in nest-site choice to be expressed, which may be important in preventing sex ratio skews due to climate change.

Seasonal Variation on the Contents of Coumarin and Kaurane‐Type Diterpenes in Mikania laevigata and M. glomerata Leaves under Different Shade Levels

Coumarin (1) and kaurane-type diterpenes are considered the bioactive constituents of Mikania glomerata and M. laevigata, used in Brazil to treat respiratory affective disorders. The seasonal variation of 1, ortho-coumaric acid (2), benzoylgrandifloric acid (3), cinnamoylgrandifloric acid (4), and kaurenoic acid (5) in leaves of both species, cultivated in full sunlight and under shade levels of 40 and 80%, was quantified by HPLC. Compound 2 was detected solely in M. laevigata in concentrations below the limit of quantification. Coumarin was not found in M. glomerata, whereas its concentration reached 0.94±0.24% (w/w) in M. laevigata farmed in summer under 80% shading. Both Mikania species produced higher amounts of kaurane diterpenes when cultivated in plenty of sunlight. Hence, maximum contents of 1 are reached in M. laevigata cultivated under high shading, but with reduced concentrations of 3-5. Conversely, M. glomerata should be cultivated under full sunlight and harvested in winter for highest concentrations of kaurane-type diterpenes.

Bell Pepper (Capsicum annum L.) Crop as Affected by Shade Level: Microenvironment, Plant Growth, Leaf Gas Exchange, and Leaf Mineral Nutrient Concentration

Use of shading nets helps ameliorate heat stress of vegetable crops. This study evaluated the effects of shade level on microenvironment, plant growth, leaf gas exchange, and mineral nutrient content of field-grown bell pepper crop. Bell pepper cultivars Camelot, Lafayette, Sirius, and Stiletto were grown at 0%, 30%, 47%, 62%, and 80% shade levels. Photosynthetically active radiation and air, leaf, and root zone temperatures decreased as shade level increased. Despite having increased plant leaf area, there was increased soil water content with increased shade level, indicating reduced soil water use. With increased shade level, the total plant leaf area, individual leaf area, and individual leaf weight increased, whereas leaf number per plant and specific leaf weight decreased. In contrast to non-normalized chlorophyll index (CI) values, CI normalized by specific leaf weight were related to leaf nitrogen (N) and increased with increased shade level. Net photosynthesis and stomatal conductance (gS) decreased and leaf transpiration increased with increased shade level, particularly above 47% shade level. Leaf concentrations of N, potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn), sulfur (S), aluminum (Al), and boron (B) increased with increased shade level. Relatively few differences in plant growth, leaf gas exchange, and leaf mineral nutrient concentrations were observed among cultivars. In conclusion, morphological changes such as taller plants and thinner and larger leaves likely enhanced light capture under shaded conditions compared with unshaded plants. High shade levels reduced leaf temperature and excessive leaf transpiration but resulted in reduced leaf photosynthesis. Thus, moderate shade levels (30% and 47%) were the most favorable for bell pepper plant growth and function.

Technical Note: Effects of Storage Container Color and Shading on Water Temperature

Rainwater harvesting (RWH) is a method of capturing rainfall from a catchment surface and storing it for later use. Though it has been around for thousands of years, its popularity and use has been increasing in recent years and water quality within RWH systems has become a concern. Water temperature is a parameter that affects water quality, and storage container color and shading affect this temperature. Rainwater storage containers with four different colors kept at three different shadings were used to study the effects of shading and container color on water temperature. Temperatures of water stored in these containers were monitored over 20 weeks during a Texas summer. Statistical analyses showed that the color and shade variables had an interaction and thus both together had an effect on the water temperature. Because of this, individual treatment variables could not be analyzed and compared statistically. However, the trends showed that light colors and higher shading caused lower water temperatures in the storage containers. Also, the color had more pronounced effect than shading on water temperature inside the containers.

Coral community changes in response to a high sedimentation event: A case study in southern Hainan Island

A high sedimentation event caused by dredging and dumping of sediment was recorded on Xiaodonghai Reef in Yulin Bay, southern Hainan Island, China. Significantly high sedimentation and constant light shading were observed during the sediment dumping event (SD Event). Using long-term video transects, we quantified coral community changes and responses to the SD Event between 2008 and 2010. The SD Event caused severe coral mortality on Xiaodonghai Reef at a depth of 6 m, while corals at 3 m were less affected. Total live coral cover at 6 m decreased from 54.3% to 14.8%, and Diploastrea heliopora replaced Galaxea fascicularis as the dominant coral species at 6 and 9 m. The density of juvenile corals also declined after the SD Event, especially for the genera Galaxea and Platygyra. However, the density of juvenile Porites and Pocillopora spp. slightly increased. Monitoring for 11 months after the SD Event indicated no recovery of coral communities on Xiaodonghai Reef. Long-term video transect data also revealed that mean live coral cover dramatically declined, from 30.5% in 2008 to 9% in 2010, while the dominant corals in Yulin Bay shifted to more tolerant coral species, such as massive Porites spp. and D. heliopora. The rapid coral community degradation in Yulin Bay between 2008 and 2010 was probably caused by high sediment deposition resulting from intensive dredging and land-clearing activities. These results highlight the necessity for an integrated watershed management to control sediment deposition on near-shore coral reefs.

Physiological and morphological responses of invasiveAmbrosia artemisiifolia(common ragweed) to different irradiances

Invasion by the exotic herb Ambrosia artemisiifolia L. has become a serious agricultural and environmental problem and of increasing research interest as the species continues its southward spread into subtropical regions of China. To better understand the possible physiological and morphological adaptations of A. artemisiifolia in this region, we conducted a greenhouse experiment using seedlings of A. artemisiifolia and a comparative native species, Urena lobata L. (Caesar’s weed), which is an erect annual shrub in the Malvaceae that commonly co-occurs with A. artemisiifolia in open, disturbed habitats in southern China. Seedlings of both plants were grown under four irradiance regimes (10%, 30%, 55%, and 100% irradiance) from 14 May to 13 July 2010. Ambrosia artemisiifolia showed significantly higher total biomass, total leaf area, specific leaf area, relative growth rate, and net assimilation rate but lower leaf mass fraction than U. lobata at the 30%–100% irradiance levels. With decreasing irradiance, A. artemisiifolia significantly increased biomass allocation to stems and decreased allocation to roots. Meanwhile, A. artemisiifolia exhibited higher light-saturated photosynthetic rates and light saturation points with wide variances except at the 10% irradiance treatment. These findings suggest that A. artemisiifolia has generally higher irradiance plasticity for traits pertaining to biomass partitioning, growth, and plant structure than U. lobata. The ability of A. artemisiifolia to tolerate high shade conditions while maintaining high growth rates at elevated irradiance levels may afford it a competitive advantage and may help explain its recent colonization and spread in southern China.

One‐sided competition for light promotes coexistence of forest trees that share the same adult height

Summary Coexistence of tree species is usually explained in relation to horizontal heterogeneity of forests caused by disturbance. In contrast, it remains unknown whether one‐sided competition for light in vertically structured forests contributes to stable coexistence of tree species that share the same adult height, even without horizontal heterogeneity. And if so, it is needed to specify the conditions of stable coexistence in terms of demographic and allometric traits between species. To answer these questions, we employ a theoretical model that describes dynamics of tree populations in forests of which vertical structure is expediently divided by height classes. We carry out analytical examination for a forest with two height classes where tree populations are adult in canopy and juvenile in understorey. Demographic processes in the canopy are regulated by foliage density in the canopy, whereas juvenile survival is suppressed by overall foliage density in both classes. A between‐species difference in juvenile/adult ratio of foliage density is required for coexistence equilibrium of two species to exist. The difference in juvenile/adult ratio in equilibrium is determined by demographic and allometric parameters of species. Trade‐offs between demographic parameters are necessary for a coexistence equilibrium which is either stable or unstable. A species with high fecundity and/or shade‐free juvenile survival can stably coexist with a species with high shade‐free growth rate and/or adult survival, whereas it cannot stably coexist with a species with high shade tolerance in growth rate and/or in adult survival. Difference in shade tolerance in juvenile survival does not contribute to stable coexistence. Height‐foliage allometry contributes only additionally to enhance coexistence equilibrium. When we divide forests into three height classes, up to three species can coexist, by means of demographic trade‐offs that bring about interspecific differentiation in vertical foliage distribution. We show all possible cases of coexistence among canopy (C), subcanopy (S) and understorey (U) species in terms of maximum adult height as follows: CCC, CCS, CCU, CSS and CSU. Synthesis. Our theoretical model shows that demographic trade‐offs among tree species with identical demographic responses to shade promotes stable coexistence through vertical foliage partitioning. This mechanism works independently of the coexistence mechanism through horizontal partitioning of patch mosaic, which is associated with interspecific difference in shade tolerance.

Geographic Distributions and Ecology of Ornamental Curcuma (Zingiberaceae) in Northeastern Thailand

The genus Curcuma is a very important economic plant. Members of this genus were used as food, medicine and ornament plants. The objectives of this study were to examine the geographic distributions and ecological conditions in the natural habitats of Curcuma in Northeastern Thailand. Species diversity was examined using the line transect method. Ecological conditions of the species were examined using a sampling plot of 20 x 20 m. A total of five species were found including Curcuma angustifolia Roxb., C. alismatifolia Gagnep., C. gracillima Gagnep., C. parviflora Wall. and C. rhabdota. These species were in an altitudinal range between 290 m and 831 m above sea level. Four species (C. angustifolia, C. alismatifolia, C. gracillima and C. rhabdota) were distributed in open gaps in dry dipterocarp forest. One species, C. parviflora was found in the contact zone between dry dipterocarp and bamboo (Gigantochloa sp.) forest. C. rhabdota was found only in a habitat with high humidity and shading along the Thailand-Lao PDR border. Significant ecological conditions of the natural habitats of these Curcuma species were identified. Altitude is the most important factor when determining the geographic distributions of these Curcuma species in Northeastern Thailand.

Optimization of quality in exported <i>Polyscias balfouriana</i> "Marginata" by using different shade levels

Foliage plant industry in Sri Lanka often has to face difficulties due to problems associated with the qualities of the final product of plant especially, pale green colour leaves and poor quality shoots, which are not accept by the buyers in export market. An investigation was carried out to develop the green colour and other qualities of Polyscias balfouriana “Marginata” (PBM) using different shade levels within 10 weeks. Canes, 10 cm long were used as planting materials and planted in coir beds under, 55, 60, 65, 70, 75, 80, 85, 90 and 95% shade levels. Other qualities evaluated for PBM were shoot length, leaf area, number of leaves per shoot. It was evident that the preferable forest green colour was achieved significantly (p = 0.001) at the highest shade levels of 85 and 90%. The leaf area of 14 cm2 and, sprout of 7 cm to 7.5 cm length also achieved at highest shade levels of 85% and 90%. Percentage of canes with 3 or more than 3 leaves per shoot was significantly higher than that of canes with less than 3 leaves at shade levels higher than the control. The higher percentage of acceptable canes with 3 or more than 3 leaves was found in shade level of 80%, 85% and 90 %. With these findings it can be concluded that the use of high shade levels such as 85% and 90% at foliage nurseries are favorable to obtain quality PBM plant for export market. DOI: http://dx.doi.org/10.4038/jas.v7i2.4403 The Journal of Agricultural Sciences, 2012, vol.7, no 2 58-65