Seedling leaves of the genus Acerfrom southern New England were compared in relation to light. The species investigated were red maple (A. rubrum L.), a species tolerant of xeric and hydric sites; silver maple (A. saccharinum L.), a... more
Seedling leaves of the genus Acerfrom southern New England were compared in relation to light. The species investigated were red maple (A. rubrum L.), a species tolerant of xeric and hydric sites; silver maple (A. saccharinum L.), a species restricted to riparian sites that are periodically flooded; and sugar maple (A. saccharum Marsh.), a mesic species of lower slopes and valleys. Germinating seedlings of all species were collected and grown within four shade treatments that had contrasting light quantity and quality: (1) approximately 100% of full sunlight, red:far-red ratio = 1.27; (2) 40% of full sunlight, ratio = 0.97; (3) 15% of full sunlight, ratio = 0.85; and (4) 4% of full sunlight, ratio = 0.46. Leaves, cuticles, and epidermal and palisade mesophyll cell layers were all thicker, and stomatal densities were higher for all three species in the full sun treatment. Dimensions of leaf structure (leaf thickness, palisade mesophyll thickness, lower epidermal thickness) were between 25 and 35% smaller for silver maple as compared to the other maples. Silver maple also allocated less biomass to roots (about 15% less) and more to stems. Its thin upper surface cuticle, thin leaves, and large leaf area predispose this species to desiccation. Phenotypic plasticity of leaf anatomical measures was greatest for red maple, suggesting it to be more of a generalist than its congeners. Red maple allocated greater biomass to roots in shade (17% and 27% more than sugar and silver maple respectively), with thicker leaves and cuticle, making it least prone to desiccation. Sugar maple had greater dry mass and total leaf area in the deepest shade than the other maples. Measures of leaf structure can provide useful insights into known ecological affinities of site and shade-tolerance among maples. FoR. Sc. 45(4):512-519.
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Maize (Zea mays L.) is an important crop used for feeding humans and cattle globally. Deficiency of potassium (K) and zinc (Zn) adversely impacts the maize crop productivity and quality. However, the application of these nutrients shows... more
Maize (Zea mays L.) is an important crop used for feeding humans and cattle globally. Deficiency of potassium (K) and zinc (Zn) adversely impacts the maize crop productivity and quality. However, the application of these nutrients shows variant responses in different maize cultivars. To understand this perspective, the current study aimed at investigating K and Zn’s optimal concentration in different hybrid and inbred maize cultivars. The treatments were based on three zinc levels (0, 6, and 12 mg Zn kg−1) and K levels (0, 30, and 60 mg kg−1), and their respective combinations. The experiment results showed that combined fertilization approaches of Zn and K (Zn12K60) improved the plant biometric, and physiological attributes of maize crop. The results revealed a significant increase in plant height (45%), fresh weight (70%), and dry weight (45%). Similarly, physiological attributes significantly improved the relative water content (76.4%), membrane stability index (77.9%), chlorophy...
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Seagrasses comprise a substantive North American and Caribbean Sea blue carbon sink. Yet fine-scale estimates of seagrass carbon stocks, fluxes from anthropogenic disturbances, and potential gains in sedimentary carbon from seagrass... more
Seagrasses comprise a substantive North American and Caribbean Sea blue carbon sink. Yet fine-scale estimates of seagrass carbon stocks, fluxes from anthropogenic disturbances, and potential gains in sedimentary carbon from seagrass restoration are lacking for most of the Western Hemisphere. To begin to fill this knowledge gap in the subtropics and tropics, we quantified organic carbon (Corg) stocks, losses, and gains from restorations at 8 previously-disturbed seagrass sites around the Gulf of Mexico (GoM) (n=128 cores). Mean natural seagrass Corg stocks were 25.7±6.7MgCorgha(-1) around the GoM, while mean Corg stocks at adjacent barren sites that had previously hosted seagrass were 17.8MgCorgha(-1). Restored seagrass beds contained a mean of 38.7±13.1MgCorgha(-1). Mean Corg losses differed by anthropogenic impact type, but averaged 20.98±7.14MgCorgha(-1). Corg gains from seagrass restoration averaged 20.96±8.59Mgha(-1). These results, when combined with the similarity between natu...
Research Interests: Environmental Science, Climate Change, Carbon, Mangroves, Carbon Cycle, and 13 moreMedicine, Multidisciplinary, Seagrass, Seagrass ecology, Seagrass and Coral Reef Restoration Projects, Caribbean region, Gulf of Mexico, Coastal marshes, Blue Carbon, Ecosystem, Hydrocharitaceae, Elsevier, and Geologic Sediments
Go to AGRIS search. Journal of home and consumer horticulture (1994). The use of a commercial organic biostimulant for improved production of marigold cultivars. ...
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A short account is given of the use and development of a non-polluting organic biostimulant (OB, defined as non-fertilizer products which have a beneficial effect on plant growth) called 'Roots' which consists of a mixture of... more
A short account is given of the use and development of a non-polluting organic biostimulant (OB, defined as non-fertilizer products which have a beneficial effect on plant growth) called 'Roots' which consists of a mixture of humic acids, marine algal extracts, a non-hormonal reductant plant metabolite and B vitamins. Brief data are presented on its use in stimulating the growth and nitrogenase activity of Alnus acuminata seedlings. The preparation has also been shown to stimulate the growth of coffee seedlings and Gliricidia sepium [seedlings].
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Abstract Ecophysiological studies that investigate species sorting across environmental gradients provide insights into the mechanisms underscoring tree distribution patterns. We examined pine functional traits by measuring a suite of... more
Abstract Ecophysiological studies that investigate species sorting across environmental gradients provide insights into the mechanisms underscoring tree distribution patterns. We examined pine functional traits by measuring a suite of physiological parameters including needle water content, spectral reflectance, transpiration decline, and leaf morphology to explore pine stratification patterns across the elevation gradient of the San Bernardino Mountains in southern California. The high and low elevation species demonstrated moisture and solar radiation tolerance. The lowest elevation species, Pinus attenuata Lem., maintained low transpiration rates under drought stress and had high concentrations of photosynthetic pigments indicating high photosynthetic capacity. Pinus coulteri Don was the most stress intolerant pine as demonstrated by high transpiration rates. Although Pinus lambertiana Doug. dominated cooler north-facing slopes, its lower transpiration rates suggested that it was well adapted to moisture stress. Pinus contorta Doug. was a typical high elevation stress tolerant tree growing under high incident solar radiation, heavy snow pack, and severe winds. Our results suggest that water availability and solar radiation intensity are the major factors influencing southern California pine distributions.
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Research Interests: Plant Biology and Biology
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It is generally held that shade-intolerant, early colonizing species demonstrate greater phenotypic plasticity than more shade-tolerant, later successional species (Ashton and Berlyn 1992). It has also been shown that the light saturation... more
It is generally held that shade-intolerant, early colonizing species demonstrate greater phenotypic plasticity than more shade-tolerant, later successional species (Ashton and Berlyn 1992). It has also been shown that the light saturation point of many temperate broadleaf tree species is about 20% to 30% of full sunlight (Chabot and Mooney 1985). Here we test two hypotheses: 1) morphological plasticity across an experimental light gradient ranging from 3% full sun to 67% full sun will be greater for the genus Betula than the genus Acer, and 2) the maximum degree of plasticity for genera and species will be expressed in the light treatment interval where photosynthetically active radiation (PAR) of 20% to 30% full sunlight occurs. Methods Seedlings of two congeneric assemblages - grey birch (Betula populifolia), paper birch (B. paperifera), yellow birch (B. alleghanensis), striped maple (Acer pennsylvanica), red maple (A. rubrum) and sugar maple (A. saccharum) - were grown over their...
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Seagrasses comprise a substantive North American and Caribbean Sea blue carbon sink. Yet fine-scale estimates of seagrass carbon stocks, fluxes from anthropogenic disturbances, and potential gains in sedimen-tary carbon from seagrass... more
Seagrasses comprise a substantive North American and Caribbean Sea blue carbon sink. Yet fine-scale estimates of seagrass carbon stocks, fluxes from anthropogenic disturbances, and potential gains in sedimen-tary carbon from seagrass restoration are lacking for most of the Western Hemisphere. To begin to fill this knowledge gap in the subtropics and tropics, we quantified organic carbon (C org) stocks, losses, and gains from restorations at 8 previously-disturbed seagrass sites around the Gulf of Mexico (GoM) (n = 128 cores). Mean natural seagrass C org stocks were 25.7 ± 6.7 Mg C org ha − 1 around the GoM, while mean C org stocks at adjacent barren sites that had previously hosted seagrass were 17.8 Mg C org ha − 1. Restored seagrass beds contained a mean of 38.7 ± 13.1 Mg C org ha − 1. Mean C org losses differed by anthropogenic impact type, but averaged 20.98 ± 7.14 Mg C org ha − 1. C org gains from seagrass restoration averaged 20.96 ± 8.59 Mg ha − 1. These results, when combine...
Research Interests: Environmental Science, Climate Change, Carbon, Mangroves, Carbon Cycle, and 12 moreMedicine, Multidisciplinary, Seagrass, Seagrass ecology, Seagrass and Coral Reef Restoration Projects, Caribbean region, Gulf of Mexico, Coastal marshes, Blue Carbon, Ecosystem, Hydrocharitaceae, and Geologic Sediments
Adaptations to resource availability strongly shape patterns of community composition along successional gradients in environmental conditions. In the present study, we examined the extent to which variation in functional composition... more
Adaptations to resource availability strongly shape patterns of community composition along successional gradients in environmental conditions. In the present study, we examined the extent to which variation in functional composition explains shifts in trait-based functional strategies in young tropical secondary forests during the most dynamic stage of succession (0-20 years). Functional composition of two size classes in 51 secondary forest plots was determined using community-weighted means of seven functional traits, which were intensively measured on 55 woody plant species (n = 875-1,761 individuals). Along the successional gradient in forest structure, there was a significant and consistent shift in functional strategies from resource acquisition to resource conservation. Leaf toughness and adult plant size increased significantly, while net photosynthetic capacity (A mass) decreased significantly during succession. Shifts in functional strategies within size classes for A mas...
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Research Interests: Monitoring And Evaluation, Life history, Biology, Sri Lanka, Sustainable, and 15 moreEcosystem health, Linear models, Sustainable forestry, Rain forest, Forests, Afforestation, Forestry Sciences, Surface Area, General Linear Model, Plant Succession, Pioneer Species, Diameter, Tree Height, high light, and Environmental factor
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Sea grasses are foundation species for estuarine ecosystems. The available light for sea grasses diminishes rapidly during pollutant spills, effluent releases, disturbances such as intense riverine input, and tidal changes. We studied how... more
Sea grasses are foundation species for estuarine ecosystems. The available light for sea grasses diminishes rapidly during pollutant spills, effluent releases, disturbances such as intense riverine input, and tidal changes. We studied how sea grasses' remote-sensing signatures and light-capturing ability respond to short term light alterations. In vivo responses were measured over the entire visible-light spectra to diminishing white-light on whole-living-plants' spectral reflectance, including 6h of full oceanic-light fluences from 10% to 100%. We analyzed differences by various reflectance indices. We compared the sea grasses species responses of tropical vs. temperate and intertidals (Halodule wrightii, and Zostera marina) vs. subtidal (Thalassia testudinum). Reflectance diminished with decreasing light intensity that coincided with greater accessory pigment stimulation (anthocyanin, carotenoids, xanthins). Chlorophyll a and Chlorophyll b differed significantly among species (Thalassia vs. Halodule). Photosynthetic efficiency diminished at high light intensities. The NDVI index was inadequate to perceive these differences. Our results demonstrate the leaf-level utility of data to remote sensing for mapping sea grass and sea grass stress.
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The use of biostimulants and bioinputs, including biofertilizers, biopesticides and microorganisms for agricultural use, has been developed considerably in the last three decades. Definitions for biostimulants vary greatly and there are... more
The use of biostimulants and bioinputs, including biofertilizers, biopesticides and microorganisms for agricultural use, has been developed considerably in the last three decades. Definitions for biostimulants vary greatly and there are still some arguments surrounding these compounds. However, they are defined as non-hormonal products which have a beneficial effect on plant growth. Many of these biostimulant materials are natural products that contain no added chemicals or synthetic plant growth regulators. Agricultural and forestry extension in biostimulants and bioinputs in Costa Rica has been a process towards sustainability.
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Maize (Zea mays L.) is an important crop used for feeding humans and cattle globally. Deficiency of potassium (K) and zinc (Zn) adversely impacts the maize crop productivity and quality. However, the application of these nutrients shows... more
Maize (Zea mays L.) is an important crop used for feeding humans and cattle globally. Deficiency of potassium (K) and zinc (Zn) adversely impacts the maize crop productivity and quality. However, the application of these nutrients shows variant responses in different maize cultivars. To understand this perspective, the current study aimed at investigating K and Zn’s optimal concentration in different hybrid and inbred maize cultivars. The treatments were based on three zinc levels (0, 6, and 12 mg Zn kg−1) and K levels (0, 30, and 60 mg kg−1), and their respective combinations. The experiment results showed that combined fertilization approaches of Zn and K (Zn12K60) improved the plant biometric, and physiological attributes of maize crop. The results revealed a significant increase in plant height (45%), fresh weight (70%), and dry weight (45%). Similarly, physiological attributes significantly improved the relative water content (76.4%), membrane stability index (77.9%), chlorophyll contents (170%), and photosynthetic rate (130%) in both inbred and hybrid genotypes. Furthermore, Zn and K (Zn12K60) increased transpiration rate (E), stomatal conductance (Ci), and internal CO2. In conclusion, maize hybrids (Neelam and DK-6142) were observed best compared with inbred (Afghoi and P-1543) cultivars with the combined application of Zn and K (Zn12K60). Thus, these inbred varieties should be preferred for fodder requirement with optimum fertilizer (Zn12K60) application in Zn deficient soils.
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The use of biostimulants and bioinputs, including biofertilizers, biopesticides and microorganisms for agricultural use, has been developed considerably in the last three decades. Definitions for biostimulants vary greatly and there are... more
The use of biostimulants and bioinputs, including biofertilizers, biopesticides and microorganisms for agricultural use, has been developed considerably in the last three decades. Definitions for biostimulants vary greatly and there are still some arguments surrounding these compounds. However, they are defined as non-hormonal products which have a beneficial effect on plant growth. Many of these biostimulant materials are natural products that contain no added chemicals or synthetic plant growth regulators. Agricultural and forestry extension in biostimulants and bioinputs in Costa Rica has been a process towards sustainability.
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ABSTRACT summarySeedlings of four species of the genus Shorea section Doona were examined. All co-exist in the moist evergreen rain forest of southwestern Sri Lanka. Experiments were designed to investigate some physiological and... more
ABSTRACT summarySeedlings of four species of the genus Shorea section Doona were examined. All co-exist in the moist evergreen rain forest of southwestern Sri Lanka. Experiments were designed to investigate some physiological and anatomical attributes of leaves under different light conditions. The attributes considered were net photosynthesis, transpiration, stomatal conductivity, blade and cuticle thickness, stomatal frequency, thickness of upper epidermis and palisade mesophyll, and number of palisade layers. Results demonstrate the close association between anatomical adaptation and efficiency in physiological processes. Results also elucidate some of the relationships between distribution patterns of species across the forest topography and their differences in light and drought tolerance. This indicates that an important period determining site specialization of a species occurs during regeneration establishment. These relationships are not as simple or as ecologically noticeable though as for those relationships documented in many previous studies between tree species of markedly different successional stages or taxonomy.
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The objective of this study was to compare the interaction between Frankia and vesicular-arbuscular mycorrhizae (VAM) on the growth response of Alnus acwninata H.B.K. seedlings under three different phosphorus levels. Alnus acuminata... more
The objective of this study was to compare the interaction between Frankia and vesicular-arbuscular mycorrhizae (VAM) on the growth response of Alnus acwninata H.B.K. seedlings under three different phosphorus levels. Alnus acuminata seedlings grown in sterile vermiculite, were inoculated with Frankia strain HFPArI3 and/or VAM (as Glomus inwa-radices) under three phosphorus levels (10.50 and 100 pg g'). After 120 days diiferences in growth were observed at the 50 pg g" P level between nodulated and non-nodulated plants; whether inoculated with Frankia + VAM or just with VAM. Interaction between Frankia and VAM was positive with respect to nodule weight at 50 pg g7' P level. The data suggest that the presence of VAM can compete with the nodules as a carbohydrate sink. At increasing levels of P the presence of Frankia alone statistically increased growth over that of the control.
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ABSTRACT It is hypothesized that root hairs serve as specialized respiratory cells concomitantly with their other functions. Occurrence of "pores" (unthickened cell walls), presence of little or no cuticle (offering... more
ABSTRACT It is hypothesized that root hairs serve as specialized respiratory cells concomitantly with their other functions. Occurrence of "pores" (unthickened cell walls), presence of little or no cuticle (offering minimum resistance for oxygen diffusion) and dense cytoplasm studded with mitochondria at Ule tip of the root hairs, are some of the special ultrastructural adaptations of root hairs which offer an indication that at least one of their main functions involves respiration. This hypothesis is based on ultrastructural evidence and comparative anatomy such as: (1) development of more dense root hairs in soil voids, (2) occurrence of dense root hairs on the juvenile primary root of viviparously germinating seeds inside the pod (e.g., Pisum sarivum and Phaseolus vulgaris seedlings grown in paper towel and glass culture); (3) occurrence of permanently open stomata in the root hair zone of some species which is believed to be a double advantage as it may enable additional diffusion of oxygen to meet greater energy requirement of growing seedling; (4) occurrence of well developed root hairs in most of the terrestrial plants and their absence or poorly developed nature in most hydrophytes; and (5) development of maximum number and length of root hairs in relatively dry and porous soils rather than wet soils. Further, the increase in surface area that root hairs provide serves as a sort of "plant gill" to maximize uptake of oxygen as well as water and nutrients.
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Nonspecific light loss by the cell-wall-plus-cytoplasm (CWC) can cause a 50% increase in Feulgen absorption units in peanut root-tip nuclei as determined by scanning at 450 nm, whereas this phenomenon is not evident with chicken... more
Nonspecific light loss by the cell-wall-plus-cytoplasm (CWC) can cause a 50% increase in Feulgen absorption units in peanut root-tip nuclei as determined by scanning at 450 nm, whereas this phenomenon is not evident with chicken erythrocytes. A two wavelength scanning method of subtracting nonspecific 450 nm absorption from 550 nm Feulgen absorption values eliminated the nonspecific light loss in CWC, However, the two wavelength scanning method is time consuming and somewhat impractical with a regular scanning microdensitometer such as Vickers M85. Elimination of the problem of nonspecific light loss is suggested by careful determination of background setting with the spot position close to the nucleus in CWC. The accuracy of the CWC background setting method was further tested by comparison with subtraction method. The use of plant nucleis as an internal standard in plant DNA measurements was also evaluated. Significant variation among the replicate slides due to the variation in p...
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Research Interests: Physiology, Forestry, Photosynthesis, Forest Ecology And Management, Forest Ecology, and 15 moreDrought Stress, Biological Sciences, Environmental Sciences, Reforestation, Drought tolerance, Precipitation, Afforestation, Light Intensity, Air Temperature, Growth rate, Adaptive capacity, Large Scale, Acacia Mangium, Native Species, and Dry Season
Research Interests: Drought Stress, Biological Sciences, Tropical trees, Environmental Sciences, Negative Affect, and 14 moreWater use efficiency, Environmental Variables, Biomass Allocation, Environmental Conditions, Light Intensity, Seedling Establishment, Adaptive capacity, Carbon Isotope Ratio, Leaf Anatomy, Low Light, Seedling Growth, Field capacity, Stomatal density, and high light
Research Interests: Developmental Biology, Fluorescence Microscopy, Biological Sciences, Mutation, Pollen, and 11 moreLectins, Reproductive Success, Plant Lectins, Arabidopsis, Plant Development, Cell Wall, Cell communication, Epidermal Stem Cells, Plant Epidermis, High Molecular Weight, and Medical and Health Sciences
Eight microsatellite loci were isolated from an enriched genomic library of the great leaf-nosed bat, Hipposideros armiger. The polymorphism of these loci was tested on a population of 48 individuals from Anhui Province, China. All loci... more
Eight microsatellite loci were isolated from an enriched genomic library of the great leaf-nosed bat, Hipposideros armiger. The polymorphism of these loci was tested on a population of 48 individuals from Anhui Province, China. All loci revealed the polymorphism ranging from three to 12 alleles. The observed heterozygosity values were from 0.213 to 0.875 and expected heterozygosity from 0.232 to
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This study examined the foliar response of putative hybrid Engelmann × white × Sitka spruce (Picea engelmannii Parry × Picea glauca (Moench) Voss × Picea sitchensis (Bong.) Carr) needles in relation to crown position and across three... more
This study examined the foliar response of putative hybrid Engelmann × white × Sitka spruce (Picea engelmannii Parry × Picea glauca (Moench) Voss × Picea sitchensis (Bong.) Carr) needles in relation to crown position and across three stages of development (15, 55, and 145 years). We focused on the morphological and anatomical response, and used physiological measures (photosynthesis and stomatal conductance) to emphasize the important relationship between structure and function. We found that needles from the upper outer crown position were adaptated to reduce stress from evapotranspiration. Trees from the 15- and 55-year-old stands generally responded the most, and trees from the 145-year-old stand responded the least. As they mature, these spruce trees may have reduced ability to adapt to their environment. Some of our results contradict what the literature considers "typical" for sun-shade dimorphism in temperate forests. For example, in all stands, sun needles were bro...