Foliage Type Research Articles

The Impact of Vegetation on Thermal Performance

This paper investigates the effect of vegetation in modifying outdoor temperature around a single-family house in a hot and humid tropical climate. The climatic parameters, house location, and physical characteristics of landscape design are measured and surveyed. The focus of this study is on the impact of trees and different types of foliage on the thermal environment of the houses. The main findings are that heavily landscape around single-family houses can potentially slow heat build-up by shading, evapotranspiration, and wind channelling by as much as 4°C.Keywords: Single-family house, thermal performance, landscape design, evapotranspirationeISSN 2398-4295 © 2018. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open-access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia. http://dx.doi.org/10.21834/ajbes.v3i11.110

The value of different vegetative indices (NDVI, GAI) for the assessment of yield potential of pea (Pisum sativum L.) at different growth stages and under varying management practices

This research evaluated the NDVI (normalized difference vegetation index) and GAI (green area index) in order to indicate the productivity and developmental effects of <em>Rhizobium inoculants</em> and microelement foliar fertilizer on pea crops. Two inoculants, Nitragina (a commercial inoculant) and IUNG (a noncommercial inoculant gel) and a foliar fertilizer (Photrel) were studied over a 4-year period, 2009–2012. The cultivars chosen for the studies were characterized by different foliage types, namely a semileafless pea ‘Tarchalska’ and one with regular foliage, ‘Klif’. Foliar fertilizer significantly increased the length of the generative shoots and the number of fruiting nodes in comparison to the control, which in turn had a negative impact on the harvest index. Pea seed yield was highly dependent on the interaction between the years of growth and the microbial inoculant, and was greater for ‘Tarchalska’ (4.33 t ha<sup>−1</sup>). Presowing inoculation of seeds and foliar fertilization resulted in a significantly higher value of GAI at the flowering (3.91 and 3.81, respectively) and maturity stages (4.82 and 4.77, respectively), whereas the value of NDVI was higher for these treatments only at the maturity stage (0.67 and 0.79, respectively). A significantly greater yield (5.0–5.4 t ha<sup>−1</sup>) was obtained after inoculation with IUNG during the dry years.

The early Miocene flora of Güvem (Central Anatolia, Turkey): a window into early Neogene vegetation and environments in the Eastern Mediterranean

AbstractThe early Burdigalian (MN3) plant assemblage of the Güvem area (northwestern Central Anatolia) is preserved in lacustrine sediments of the Dereköy pyroclastics. Its age is well constrained by radiometric dates of basaltic rocks bracketing the pyroclastics, making the Güvem flora one of the extremely few precisely dated early Miocene floras in the Mediterranean region. The rich assemblage of impression fossils comprises ferns and fern allies (2 species), gymnosperms (12 spp.) and angiosperms (129 spp.).Ilex miodipyrenasp. nov. is described as a new fossil-species. The most diverse families in the assemblage are the Fagaceae with 12 taxa and the Fabaceae with 12 leaf morphotypes and one fruit taxon. Aquatic plants are represented by seven taxa, riparian (including palms) and swamp forest elements by >35 taxa, and lianas by three taxa (Smilaxspp.,Chaneya). The relatively large number of aquatic and riparian/swamp elements is congruent with the rich fish, amphibian and reptile record of the Güvem area. Another characteristic feature of the plant assemblage is the presence of various lobed leaves which show similarities with modern species of different families (e.g.Alangium, various Malvales). Trees and shrubs growing on well-drained soils and forming closed-canopy and open-canopy forests are the most diversified group (>70 taxa). In terms of number of specimens in the collection and based on field observations, by far the most abundant leaf fossils belong to evergreen oaks ofQuercus drymejaandQ. mediterraneaand to various types of foliage that cannot be assigned to a particular extant or extinct genus of Fagaceae. These sclerophyllous trees must have covered vast areas surrounding the wetlands that developed during the early Miocene in the Güvem Basin. Based on a recent reassessment of the ecology and taxonomic affinity of these trees, they are considered to reflect humid temperate climatic conditions but with a brief drier season during the winter months. These forests are more similar to the laurel forests of the southeastern United States and those stretching in a narrow belt south of the Himalayas to eastern central China. The large number of Fabaceae may indicate the presence of warm subtropical environments but this is difficult to assess, as they are known for having wide ecological ranges today and in the past. All in all, a larger part of the plant taxa point to forested vegetation. This is in agreement with previous palynological studies which detected only small amounts of herbaceous and grass pollen. Open patches of vegetation may have been restricted to river banks and to rocky areas in a volcanic landscape. The biogeographic patterns detected for the early Miocene of the Güvem assemblage are manifold; most taxa are widespread Northern Hemispheric elements. A substantial part of the species migrated from Asia into Europe during the (late) Paleogene and reached Anatolia during the early Miocene (Fagus,Paliurus,Chaneya,Ailanthus,Quercus kubinyii,Davallia haidingeri,Acer angustilobum,A. palaeosaccharinum). Fewer taxa may have been in Anatolia before they migrated to Europe (e.g.Nerium,Smilax miohavanensis,Quercus sosnowskyi). Finally, very few taxa are Anatolian endemics (e.g.Ilex miodipyrena).

A computational model for biosonar echoes from foliage.

Since many bat species thrive in densely vegetated habitats, echoes from foliage are likely to be of prime importance to the animals’ sensory ecology, be it as clutter that masks prey echoes or as sources of information about the environment. To better understand the characteristics of foliage echoes, a new model for the process that generates these signals has been developed. This model takes leaf size and orientation into account by representing the leaves as circular disks of varying diameter. The two added leaf parameters are of potential importance to the sensory ecology of bats, e.g., with respect to landmark recognition and flight guidance along vegetation contours. The full model is specified by a total of three parameters: leaf density, average leaf size, and average leaf orientation. It assumes that all leaf parameters are independently and identically distributed. Leaf positions were drawn from a uniform probability density function, sizes and orientations each from a Gaussian probability function. The model was found to reproduce the first-order amplitude statistics of measured example echoes and showed time-variant echo properties that depended on foliage parameters. Parameter estimation experiments using lasso regression have demonstrated that a single foliage parameter can be estimated with high accuracy if the other two parameters are known a priori. If only one parameter is known a priori, the other two can still be estimated, but with a reduced accuracy. Lasso regression did not support simultaneous estimation of all three parameters. Nevertheless, these results demonstrate that foliage echoes contain accessible information on foliage type and orientation that could play a role in supporting sensory tasks such as landmark identification and contour following in echolocating bats.

Woody-plant ecosystems under climate change and air pollution-response consistencies across zonobiomes?

Forests store the largest terrestrial pools of carbon (C), helping to stabilize the global climate system, yet are threatened by climate change (CC) and associated air pollution (AP, highlighting ozone (O3) and nitrogen oxides (NOx)). We adopt the perspective that CC-AP drivers and physiological impacts are universal, resulting in consistent stress responses of forest ecosystems across zonobiomes. Evidence supporting this viewpoint is presented from the literature on ecosystem gross/net primary productivity and water cycling. Responses to CC-AP are compared across evergreen/deciduous foliage types, discussing implications of nutrition and resource turnover at tree and ecosystem scales. The availability of data is extremely uneven across zonobiomes, yet unifying patterns of ecosystem response are discernable. Ecosystem warming results in trade-offs between respiration and biomass production, affecting high elevation forests more than in the lowland tropics and low-elevation temperate zone. Resilience to drought is modulated by tree size and species richness. Elevated O3 tends to counteract stimulation by elevated carbon dioxide (CO2). Biotic stress and genomic structure ultimately determine ecosystem responsiveness. Aggrading early- rather than mature late-successional communities respond to CO2 enhancement, whereas O3 affects North American and Eurasian tree species consistently under free-air fumigation. Insect herbivory is exacerbated by CC-AP in biome-specific ways. Rhizosphere responses reflect similar stand-level nutritional dynamics across zonobiomes, but are modulated by differences in tree-soil nutrient cycling between deciduous and evergreen systems, and natural versus anthropogenic nitrogen (N) oversupply. The hypothesis of consistency of forest responses to interacting CC-AP is supported by currently available data, establishing the precedent for a global network of long-term coordinated research sites across zonobiomes to simultaneously advance both bottom-up (e.g., mechanistic) and top-down (systems-level) understanding. This global, synthetic approach is needed because high biological plasticity and physiographic variation across individual ecosystems currently limit development of predictive models of forest responses to CC-AP. Integrated research on C and nutrient cycling, O3-vegetation interactions and water relations must target mechanisms' ecosystem responsiveness. Worldwide case studies must be subject to biostatistical exploration to elucidate overarching response patterns and synthesize the resulting empirical data through advanced modelling, in order to provide regionally coherent, yet globally integrated information in support of internationally coordinated decision-making and policy development.

The nocturnal larvae of a specialist folivore prefer Chromolaena odorata (L.) foliage from a sunny environment, but does it matter?

Increasing evidence suggests that the responses of insect herbivores to environment-mediated changes in the phenotypic and phytochemical traits of their host plants are more complex than previously thought. Here, we examined the effects of habitat conditions (shaded versus full-sun habitats) on plant traits and leaf characteristics of the invasive alien plant, Chromolaena odorata (L.) (Asteraceae). We also determined neonate larval preference of the specialist herbivore, Pareuchaetes pseudoinsulata Rego Barros (Lepidoptera: Erebidae) (a biological control agent) for shaded versus full-sun leaves. The study further evaluated the performance of the moth on C. odorata leaves obtained from both shaded and full-sun habitats. Leaves of C. odorata plants growing in the shaded habitat had higher water and nitrogen contents compared with full-sun leaves. Plants growing in shade had longer leaves but full-sun plants were taller and had greater aboveground biomass compared with shaded plants. Although neonate larvae of P. pseudoinsulata preferred to feed on full-sun foliage, development was faster when reared on shaded foliage. However, survival, pupal mass, growth rate, and Maw’s host suitability index of the moth did not significantly differ between full-sun and shaded foliage. Our inability to demonstrate significant differences in key insect performance metrics in P. pseudoinsulata between shaded and full-sun foliage, despite neonate larval preference for one of the foliage types, suggests that neither of the foliage types can be considered a superior host, and reiterate the fact that relationships between host plant quality (modulated by light intensity) and phytophagous insect performance are not simple.

Differences in carbon isotope discrimination and whole-plant transpiration efficiency among nine Australian and Sahelian Acacia species

We observed coordinated differences in water-use efficiency, 13 C isotope composition, and whole-plant transpiration efficiency among nine Acacia species, although the up scaling from leaf to whole-plant level resulted in different relationships in Sahelian and Australian species. The genus Acacia sensu lato contains a large variety of tropical to Mediterranean species adapted to habitats ranging from mesic to arid in Africa and Australia. We checked whether transpiration efficiency differed among a range of nine Sahelian and Australian species and whether it was related to the degree of aridity of the original area or to their type of foliage (pinnate leaves or phyllodes). Intrinsic water-use efficiency (W I) was recorded from leaf gas exchange and whole-plant transpiration efficiency (TE) from biomass production and water consumption of potted seedlings. Both W I and TE were compared to 13C discrimination (Δ13C) computed from either bulk foliage or extracted cellulose. At leaf level, Δ13C matched closely W I across species, while at the whole-plant level, the relationship between TE and either Δ13C or W I differed between the Sahelian and the Australian species. Large interspecific differences were found but they were not related to the aridity of the origin nor to the type of foliage. Δ13C captured well the variability of W I among several Acacia species while species differences in carbon-use efficiency (the fraction of carbon assimilated recovered in plant biomass) or the relative nocturnal transpiration may disrupt the relationship between TE and Δ13C.

Evaluation of yielding of mixtures of Pisum sativum L. with Triticum aestivum L. grown in organic farming

<p>The aim of this study was to determine the productivity and quality of feed obtained from the mixtures of field pea (<em>Pisum sativum</em> L.) with spring wheat (<em>Triticum aestivum</em> L.), depending on the pea cultivar and its percentage in the weight of sown seeds under the conditions of organic farming. A field experiment was carried out in the years 2011–2013 in a randomized split-plot design with four replications. The first factor was a pea ‘Wiato’ or ‘Tarchalska’. The secondary factor was density of a pea mixture sown: 40, 60, and 80%. The yield of mixture seeds as well as the yield and structure of individual components were evaluated. The contents of crude protein and crude fiber, fat, ash, phosphorus, and potassium were determined in cereal grain and pea seeds.</p><p>The examined factors and weather conditions during the growing season had a significant impact on the growth and yield of pea–spring wheat mixtures. The seed yields of the mixtures with the semi-leafless ‘Tarchalska’ were lower than with ‘Wiato’ (with bipinnate leaves). Increasing the pea percentage in seed material resulted in lower mixture yields. The percentage of pea seeds (regardless of foliage type) in the mixture yields was significantly lower than the weight of sown seeds. Increasing the pea percentage in the mixture yield positively influenced the contents of protein, fat, and ash but it caused a decrease in the content of fiber. The pea percentage at sowing had little influence on the content of phosphorus in the mixture seed yields, but it slightly increased the content of potassium, regardless of the pea cultivar. The mixtures with the ‘Wiato’ and ‘Tarchalska’ cultivars contained a similar amount of protein, fiber, and fat, while the mixtures with ‘Tarchalska’ accumulated more ash.</p>

Inheritance and allelism of morphological traits in eastern redbud (Cercis canadensis L.).

Inheritance of purple, gold, and variegated foliage types, weeping architecture, and double flower was explored in F1, F2, and backcross families resulting from controlled hybridization of eastern redbud (Cercis canadensis L.). Potential allelic relationships were explored when possible. Inheritance analysis in families derived from controlled hybridization of ‘Covey’ (green leaf) and ‘Forest Pansy’ (purple leaf) suggest that purple leaf color and weeping architecture are both controlled by single recessive genes, for which the symbols pl1 and wp1 are proposed, respectively. Inheritance of gold leaf was explored in families of ‘Covey’ (green leaf) × ‘Hearts of Gold’ (gold leaf). Interpretation of inheritance of gold leaf in these families was confounded by the recovery of a leaf color phenotype in the F2 family unlike either parent. However, data suggested the action of a single locus controlling gold leaf color in ‘Hearts of Gold’, and that instability of gold leaf expression may be based on transposable element activity. Segregation of gold leaf in the F2 families of ‘Texas White’ [green leaf (C. canadensis var. texensis)] × ‘JN2’ [gold leaf (The Rising Sun)] did not fit a Mendelian ratio. Analysis of progeny of ‘Silver Cloud’ and ‘Floating Clouds’ (both showing white/green leaf variegation) with non-variegated cultivars demonstrated that variegation in ‘Silver Cloud’ is controlled by a single recessive nuclear gene, while variegation in ‘Floating Clouds’ is controlled by cytoplasmic factors. The symbol var1 is proposed for the gene controlling variegation in ‘Silver Cloud’. Double flower in progeny derived from ‘Flame’ (double flower) suggested that double flower is dominant to single flower, and that ‘Flame’ is heterozygous at the double-flower locus, for which the symbol Df1 is proposed. Allelism studies showed that the gene controlling purple leaf in ‘Forest Pansy’ is allelic to the purple leaf gene in ‘Greswan’ and that the gene controlling weeping phenotype in ‘Traveller’ (C. canadensis var. texensis) is non-allelic to the weeping gene found in ‘Covey’. Allelism of the gold leaf trait in ‘Hearts of Gold’ and ‘JN2’ was investigated, but no clear conclusions regarding allelism could be made due to recovery of leaf color phenotypes unlike either parent.

Behavioral Responses ofLaricobiusspp. and Hybrids (Coleoptera: Derodontidae) to Hemlock Woolly Adelgid and Adelgid Host Tree Odors in an Olfactometer

The predatory species Laricobius nigrinus (Fender) and Laricobius osakensis (Shiyake and Montgomery) (Coleoptera: Derodontidae) have been released for biological control of hemlock woolly adelgid (Adelges tsugae; Hemiptera: Adelgidae) in eastern North America. L. osakensis is native to Japan, whereas L. nigrinus is endemic to the Pacific Northwest of the United States and Canada. After release, L. nigrinus was found to hybridize with the native eastern species, Laricobius rubidus (LeConte). The purpose of this study is to observe prey location behaviors of these three Laricobius species and L. nigrinus × L. rubidus (Ln × Lr) hybrids. Olfactometer bioassays were used to test response to host odors of adelgid-infested eastern hemlock, uninfested eastern hemlock, and uninfested eastern white pine. Predators reacted in the olfactometer more quickly when adelgid-infested foliage was included as a choice. L. nigrinus preferred infested eastern hemlock over uninfested eastern white pine, and L. rubidus preferred uninfested eastern white pine over uninfested eastern hemlock. Laricobius hybrids did not show a preference for foliage types known to be primary adelgid hosts (eastern hemlock and eastern white pine). Unequal preference by species of Laricobius for host trees of different adelgid prey could therefore be maintaining Laricobius species barriers despite hybridization. L. osakensis for this study were reared in the laboratory, whereas other species in this study were collected from the field, yet still were attracted to infested and uninfested eastern hemlock. This species also responded most quickly in the olfactometer, which is encouraging for successful biological control with this species.

Quantitative Analysis of Induced Phenotypic Diversity in Chickpea Using Physical and Chemical Mutagenesis

In the present scenario of variable natural environment and sky-high population, sustainable boost in the agricultural productivity is the utmost priority. Induce mutagenesis generates noble genetic combination without affecting the overall genomic makeup of crop, thus, providing essential genetic variation for any crop improvement programme. The present study has been carried out to investigate the comparative mutagenicity of gamma rays and HZ on chickpea (Cicer arietinum L.) genotype (avrodhi) at M2 generation developed from seeds of treated M1 plants population. The assessment on phenotypic expression for the studied qualitative and quantitative traits showed considerable deviations in all the treatments and significant positive shift in 0.01 and 0.02% doses compared to control while 0.04% proved to be most mutagenic with highest significant negative deviation. A broad spectrum and frequency of macro mutations were induced affecting all plant parts and different morphological variants were screened and isolated on the basis of economic importance from the treated populations. Economically important mutations like branching pattern, stem structure, plant height, dwarf and bushy growth habit, foliage type, flowering behavior and maturity were identified and the frequency of the variants were found to be more in 0.03% doses. Explicitly, HZ doses provided greater deviations in both directions in the quantitative phenotypic characters studied while frequencies of distinct morphological mutants were more in gamma rays. The induced elite phenotypes (blue flowered, double flowered, pigmented leaf, bushy and early mutants), having strong correlation with agronomic traits, will definitely be helpful in selection of improved mutants in subsequent generations.

EFFECT OF GENOTYPE, ENVIRONMENT, GROWTH STAGE, AND FOLIAGE TYPE ON AMERICAN ELDERBERRY LEAF ELEMENTAL STATUS

Foliar analysis is a useful monitoring tool to evaluate the efficacy of fertilizer application for horticultural crops. Tracking seasonal variations in leaf element contents can help producers in scheduling soil and foliar nutrient applications. The American elderberry (Sambucus nigra subsp. Canadensis) is increasingly cultivated in North America, yet information on sufficiency levels of leaf element content and seasonal variation is lacking. A study was conducted in 2006 at two locations in Missouri (USA) to measure the leaf content of N, P, K, Ca, Mg, Fe, Cu, Zn, Mn and B. Foliage from new shoots arising either from crowns at soil level or from above-ground woody stems was sampled from three elderberry genotypes at three growth stages (spring flush, anthesis, and fruit ripening) at two locations. Significant differences were noted among the three genotypes for all foliar elements except Cu, and between the two sites for all except Fe and Cu. Leaf element levels of Ca, Mg, and B increased significantly over the growing season, while levels of N, P, K, and Zn decreased. In several cases (N, P, K, Zn, Mn) significant differences in element content were observed between the two foliage types. A number of significant interactions were noted among the variables. Additional work is needed to further develop foliar analysis as a tool for elderberry producers.

Effect of plant types on grain yield and lodging resistance in pea (Pisum sativum L.)

In the present experiment 56 diverse pea genotypes were chosen belonging to seven different plant type groups and observations were made on eight traits related to yield and lodging. Normal foliage with reduced stipule plant type (stst genotype) found to be shortest (in terms of days to flowering and days to maturity) while, semi-leafless plant type had the highest 100-seed weight as compared to the normal plant types (LeLe AfAf TlTl StSt). On the other hand, the pleiofila with reduced stipule foliage type (afaf tltl stst) had smallest 100-seed whereas, seed yield per plant was highest in case of semi-leaf plant types in both tall and dwarf groups. Similarly, Pleiofila with normal and reduced stipule plant types in both tall and dwarf groups were found to be more lodging susceptible than the normal. The dwarf/semi-dwarf genotypes combined with semi-leafless peas appear to be the most ideal plant type that would provide better tolerance to lodging and yields high.

A Study of Foliage Morphological Descriptions Accommodating Continuity in Previous Delimitation of Types in Tropical Plants

The morphological description of some selected tropical plants in Ogun State, Nigeria was investigated. This is with a view to bridge existing more or less compartmentalized foliar descriptions which are discrete and lack the observed continuum of shape types in nature. Plants from which leaves were collected and observed for the different traits were randomly collected from some Local Government Areas of the State. The qualitative macromorphological characters observed include, leaf type, leaf shape, leaf apex, leaf base and leaf margin with varying percentage occurrence. Of the 74 distinct foliage types examined 62(84%) matched the existing foliage descriptions in literature while 12(16%) had undefined shape descriptions. It was observed that simple (79%), ovate and lanceolate (18%), entire (58%), acute (26%), acute (44%) had the highest frequency for the leaf type, leaf shape, leaf margin, leaf apex and leaf bases respectively, while the lowest frequency was recorded to be compound (21%), linear, oblanceolate, acicular, orbicular, sagitate, falcate, peltate, hastate, lobed (1.6%), spinose, denticulate, crenate, parted (1.6%), mucronulate and cirrhose (1.6%), auriculate and hastate (1.6%) in the leaf type, leaf shape, leaf margin, leaf apex and leaf bases respectively. Other shapes hitherto undefined include: lanceospatulate, zygomorphic-trilobe, ensiformis, lobed-pentate, lobed-starlate and ellipto-dentoid. The study revealed that there is a continuum in plant foliage macromorphological description rather than independent occurrence of plant foliage characters found in literature.

Genetic and ontogenetic variation in an endangered tree structures dependent arthropod and fungal communities.

Plant genetic and ontogenetic variation can significantly impact dependent fungal and arthropod communities. However, little is known of the relative importance of these extended genetic and ontogenetic effects within a species. Using a common garden trial, we compared the dependent arthropod and fungal community on 222 progeny from two highly differentiated populations of the endangered heteroblastic tree species, Eucalyptus morrisbyi. We assessed arthropod and fungal communities on both juvenile and adult foliage. The community variation was related to previous levels of marsupial browsing, as well as the variation in the physicochemical properties of leaves using near-infrared spectroscopy. We found highly significant differences in community composition, abundance and diversity parameters between eucalypt source populations in the common garden, and these were comparable to differences between the distinctive juvenile and adult foliage. The physicochemical properties assessed accounted for a significant percentage of the community variation but did not explain fully the community differences between populations and foliage types. Similarly, while differences in population susceptibility to a major marsupial herbivore may result in diffuse genetic effects on the dependent community, this still did not account for the large genetic-based differences in dependent communities between populations. Our results emphasize the importance of maintaining the populations of this rare species as separate management units, as not only are the populations highly genetically structured, this variation may alter the trajectory of biotic colonization of conservation plantings.

Soil N forms and gross transformation rates in Chinese subtropical forests dominated by different tree species

Background and aims Knowledge related to extent of differing soil N forms and N transformation rates in subtropical southern China is severely limited. Accordingly, the purpose of this study was to investigate if and how tree species of different foliage types (coniferous, deciduous, and evergreen broadleaved) influence N forms and microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) content as well as gross N transformation rates in the organic and mineral soils of three distinct subtropical forests in China.

Combined effects of pre-hardening and fall fertilization on nitrogen translocation and storage in Quercus variabilis seedlings

Maintaining proper seedling nitrogen status is important for outplanting success. Fall fertilization of evergreen conifer seedlings is a well-known technique for averting nitrogen (N) dilution caused by continued seedling growth during hardening. For deciduous seedlings, this technique is much less understood, and regardless of foliage type, the interaction of N status prior to fall fertilization and the rate of fall fertilization have yet to be fully explored. Therefore, we fertilized Quercus variabilis container seedlings with either 25, 100, or 150 mg total N seedling−1, applied exponentially, during a 23-week pre-hardening regime, followed by either 0, 12, or 24 mg total N seedling−1 applied during hardening (i.e., fall fertilization) in equal aliquots for 4 weeks. For seedlings without supplemental N during hardening, N concentration in stems and roots increased significantly despite substantial growth. The absence of N dilution was attributed to N translocation from foliage to these tissues, which was independent of pre-hardening N status. Overall, 32 % of foliar N was translocated and accounted for 75 % of the total N increase in stems and roots. Final stem N status was a function of pre-hardening fertilization, whereas root N concentration was affected by the interaction of pre-hardening and fall fertilization. Roots appear to be the main site of N storage, and root N content was significantly affected by pre-hardening and fall fertilization, but not their interaction. A combination of pre-hardening and fall fertilizer at a rate of 100 and 24 mg total N seedling−1, respectively, yielded seedlings with the largest root systems.

Modifying the Outdoor Temperature around Single-Family Residences: The Influence of Landscaping

This paper investigates the effect of vegetation in modifying outdoor temperature around a single-family house in a hot and humid tropical climate. The climatic parameters, house location, and physical characteristics of landscape design are measured and surveyed. The focus of this study is on the potential impact of trees and different types of foliage on the thermal environment of the houses. The main findings are that heavily landscape around single-family houses can potentially slow heat build-up by shading, evapotranspiration, and wind channelling by as much as 4°C.

Responses of foliar antioxidative and photoprotective defence systems of trees to drought: a meta-analysis

Current climate change predictions hint to more frequent extreme weather events, including extended droughts, making better understanding of the impacts of water stress on trees even more important. At the individual plant level, stomatal closure as a result of water deficit leads to reduced CO2 availability in the leaf, which can lead to photo-oxidative stress. Photorespiration and the Mehler reaction can maintain electron transport rates under low internal CO2, but result in production of reactive oxygen species (ROS). If electron consumption is decreased, upstream photochemical processes can be affected and light energy is absorbed in excess of photochemical requirements. Trees evolved to cope with excess energy and elevated concentration of ROS by activating photoprotective and antioxidative defence systems. The meta-analysis we present here assessed responses of these defence systems reported in 50 studies. We found responses to vary depending on stress intensity, foliage type and habitat, and on whether experiments were done in the field or in controlled environments. In general, drought increased concentrations of antioxidants and photoprotective pigments. However, severe stress caused degradation of antioxidant concentrations and oxidation of antioxidant pools. Evergreen trees seemed to preferentially reinforce membrane-bound protection systems zeaxanthin and tocopherol, whereas deciduous species showed greater responses in water-soluble antioxidants ascorbic acid and glutathione. Trees and shrubs from arid versus humid habitats vary in their antioxidative and photoprotective defence responses. In field experiments, drought had greater effects on some defence compounds than under controlled conditions.

The Effect of Landscaping on the Thermal Performance of Housing

The heat island effect influences most of the major cities around the world. This urban phenomenon occurs because air temperatures in densely built urban areas are higher than the temperatures of the surrounding rural countryside. In tropical cities, the exterior environment is already extremely warm due to high air temperatures, especially during dry seasons. However careful planning and development of exterior spaces can reduce the adverse impact of these temperatures. This paper investigates the effect of landscaping on the thermal performance of housing in a hot-humid tropical climate. The climatic parameters, physical characteristics of building construction, and landscape design of three private houses in Shah Alam, Selangor, Malaysia were measured and surveyed. The study focuses on the potential impact of shade trees and different types of foliage on the thermal performance of houses of different ages. Sets of instrument were placed in several outdoor and indoor locations around the houses. Result show that the outdoor air temperatures of the well-landscaped houses were usually lower compared to the minimally- landscaped house. The main findings show that well-designed landscaping around single-family houses could potentially reduce heat build-up by shading, evapotranspiration, and wind channelling by as much as 3°C.