Vegetative Compartments Research Articles

Plant Uptake of Per- and Polyfluoroalkyl Substances at a Contaminated Fire Training Facility to Evaluate the Phytoremediation Potential of Various Plant Species.

Fire training facilities and other areas suffer from serious per- and polyfluoroalkyl substance (PFAS) contamination in soil, surface water, and groundwater due to regular practices with PFAS-containing aqueous firefighting foams (AFFFs). Therefore, the uptake of 26 PFASs in plants and the contamination of soil and groundwater has been investigated at a fire training site at Stockholm Arlanda airport, Stockholm (Sweden) in 2016. Elevated ∑26PFAS levels were detected in soil and groundwater ranging from 16 to 160 ng g-1 dry weight (dw) and 1200-34 000 ng L-1, respectively. Samples from different plant species and tissues (i.e., roots, trunk/cores, twigs, leaves/needles) of the local plant community were taken, namely silver birch (Betula pendula), Norway spruce (Picea abies), bird cherry (Prunus padus), mountain ash (Sorbus aucuparia), ground elder (Aegopodium podagraria), long beechfern (Phegopteris connectilis), and wild strawberry (Fragaria vesca). The plants showed a high variability of concentrations with highest ∑26PFAS concentrations in vegetative compartments with up to 97 ng g-1 wet weight (ww) and 94 ng g-1 ww in birch leaves and spruce needles, respectively. Annual ground cover plants such as long beechfern and ground elder, and bushes like bird cherry showed concentrations up to 6.9, 23, and 21 ng g-1 ww, respectively. The bioconcentration factors (BCFs; plant/soil ratios) were highest in foliage, while the total tree burden of ∑26PFASs per tree was up to 11 mg for birch and 1.8 mg for spruce. Considering a shelterwood system with mixed stands of silver birch and spruce in combination with regular harvest of leaves and birch sap and an understory of ground elder, it is potentially feasible to remove 1.4 g of ∑26PFASs per year and hectare from (heavily) contaminated sites. An alternative approach is the coppicing of birch trees in combination with an understory of ground elder, potentially removing 0.65 g yr-1 ha-1 of ∑26PFASs, while a simple meadow with ground elder can remove 0.55 g yr-1 ha-1 ∑26PFASs.

Transformation of the Solanum tuberosum with Saccharomyces cerevisiae Gene Suc2 Encoding Cell-Wall Invertase Influences on Sugars Distribution in Plants

Introduction: Invertase is the key enzyme of carbohydrate metabolism, which catalyzes the sucrose hydrolysis. In this study, we investigated a functional role of the apoplastic invertase (cell-wall invertase) on sugars distribution in vegetative organs and cell compartments of potato plants in vitro.Methods: Our study was carried out with potato (S. tuberosum L., cv. Desiree) plants and the line which expressed the suc2 gene of S. cerevisiae under control of the tuberspecific patatin B33-promoter of class I with an N-end-connected potato proteinase II inhibitor signal peptide, which provides apoplastic localization of yeast invertase. The suc2 gene expression were shown using RT-PCR. The results of Ds-Na-PAGE of apoplast proteins from leaves and MALDI-TOF MS analysis indicate the presence of the yeast invertase in the apoplastic space of the transgenic potato plants. The content of fructose and sucrose was determined according to Roe. The glucose content was determined by the glucose oxidase method.Results: The integrated target suc2 gene encodes the invertase of yeast with an N-endconnected potato proteinase II inhibitor signal peptide, which provides apoplastic localization of foreign invertase.Conclusions: Transformation of potato plants resulted in accumulation of fructose in the apoplast, sucrose and glucose in the leaves, and especially, glucose in roots and microtubers. It is indicative of regulatory function of cell-wall invertase that could be found some application in medical, biological and pharmaceutical engineering.

Identification, distribution, and quantification of biominerals in a deciduous forest.

Biomineralization is a common process in most vascular plants, but poorly investigated for trees. Although the presence of calcium oxalate and silica accumulation has been reported for some tree species, the chemical composition, abundance, and quantification of biominerals remain poorly documented. However, biominerals may play important physiological and structural roles in trees, especially in forest ecosystems, which are characterized by nutrient-poor soils. In this context, our study aimed at investigating the morphology, distribution, and relative abundance of biominerals in the different vegetative compartments (foliage, branch, trunk, and root) of Fagus sylvatica L. and Acer pseudoplatanus L. using a combination of scanning electron microscopy and tomography analyses. Biomineral crystallochemistry was assessed by X-ray diffraction and energy-dispersive X-ray analyses, while calcium, silicon, and oxalic acid were quantified in the compartments and at the forest scale. Our analyses revealed that biominerals occurred as crystals or coating layers mostly in bark and leaves and were identified as opal, whewellite, and complex biominerals. In both tree species, opal was mostly found in the external tissues of trunk, branch, and leaves, but also in the roots of beech. In the stand, opal represents around 170kg/ha. Whewellite was found to suit to conductive tissues (i.e., axial phloem parenchyma, vascular bundles, vessel element) in all investigated compartments of the two tree species. The shape of whewellite was prismatic and druses in beech, and almost all described shapes were seen in sycamore maple. Notably, the amount of whewellite was strongly correlated with the total calcium in all investigated compartments whatever the tree species is, suggesting a biologic control of whewellite precipitation. The amount of whewellite in the aboveground biomass of Montiers forest was more important than that of opal and was around 1170 kg/ha. Therefore, biominerals contribute in a substantial way to the biogeochemical cycles of silicon and calcium.

Consolidating the Feedstock Crops Cellulosic Biodiesel with Cellulosic Bioethanol Technologies: A Biotechnology Approach

At present, the US is the largest producer of bioethanol (i.e. ethanol mostly produced from corn seed starch), and biodiesel (i.e. oil produced from oil seed crops). Considering controversies around whether governments should allow the conversions of food and feed into fuels or should they put a limit on such conversions, the future market potentials for crop vegetative wastes cellulosic bioethanol and cellulosic biodiesel is enormous. The majority of crop lipids are in the seeds of oil seed crops. In certain cases such as in palm oil and olive trees, the majority of lipids are in the crop fruit. Lipids also exist in crop vegetative tissues including leaves, stems and husks. However, lipids of the vegetative tissues are at very low levels and mostly are in cell membranes and outside of the leaf epidermis in form of wax. For example, the lipids per dry weight of oil seeds and oil fruits could be as high as ~80-90%, while the vegetative tissues of normally contain less than 2-3% lipids. A couple of most recent review articles show that it is possible to increase the lipid contents of plants vegetative tissues via metabolic engineering. A couple of other scientific teams were recently able to produce high quantities (9.5 to 17% per dry matter) of high density oil in form of triacylglyceride (TAG) in sugarcane and tobacco (Nicotiana tobacum) leaves. The author’s team also recently developed 3rd generation of metabolically engineered maize plants that are producing abundant oil droplets in their leaf cells (unpublished data). It is also possible to shift the fatty acid contents of cellulosic oil from biodiesel oil to vegetable oil by overexpressing of certain genes that are associated with lipid biosynthesis. The overexpression of certain other genes associated with lipid biosynthesis can result in productions of unusual fatty acids such as epoxy fatty acids, and fatty acids of acyl triglycerides, or can result in a shift of fatty acids from one type to another. Therefore, it is expected that biodiesel can be produced in crops vegetative biomass for extraction and use, and its fatty acid content be modified as might become needed. On the other hands, cellulosic ethanol is produced through the use of microbial cellulases that convert crop cellulose into fermentable sugars and via pretreatment processes that either breakdown or remove the lignin component of lignocellulosic biomass to allow the exposure of cellulose of the lignocellulosic matter to cellulase enzymes. However, production of microbial cellulases and pretreatment processes of lignocellulosic matter are very expensive. To cut the costs of production of cellulosic ethanol, microbial heterologous cellulases have been produced within the crop vegetative biomass, specifically inside crops vegetative biomass sub-cellular compartments, including the apoplast (i.e. the free space outside of the plasma membrane and the cell wall), chloroplast, vacuole and mitochondria or within multiple number of sub-cellular compartments. In addition, lignin of crop vegetative biomass has been reduced via the RNA interference (RNAi) technology and the lignin structure has been changed in a manner that it can be broken down easily with minimum needs for pretreatment processes. This Editor believes that it must be possible to produce high density lipids as biodiesel via metabolic engineering, extract the biodiesel oil and then convert the lignocellulosic residues into cellulosic ethanol. In fact the two biofuels production systems are well compatible with the existing cellulosic ethanol refinery. Such integrated technology can contribute towards replacing of the environmentally harmful and nonrenewable petroleum fuel to cellulosic biofuels without replacing of the food or feed for fuels. Technologies associated with cellulosic biofuels are not difficult and could be used around the globe especially in countries where abundant crop residues such as rice straws are burned to waste, creating environmental contaminations and human health problems including asthma.

YOUNG FLUSH THINNING IN MANGO (CV. COGSHALL) CONTROLS CANOPY DENSITY AND PRODUCTION

Although mango has been grown for a very long time and cultivation is increasing, productivity is still low and irregular. In this work, we took up the common hypotheses in which fruiting under hot subtropical conditions competes strongly for limited carbon resources, and the strategy of the mango tree is to adjust carbon investment between the fruit and vegetative compartments. If flowering is too abundant for mango tree, the assimilates produced by photosynthesis will not fit the demand during fruit set and growth. However, rather than favouring vegetative development by heading cuts, we decreased the number of vegetative flushes (physiological sinks) by thinning cuts of young flushes as soon as they appear in order to improve their development and to increase flower induction in their terminal bud. In Reunion Island, we developed a young flush thinning cut protocol which aimed at optimising, at mango tree level, the source/sink relationships for carbohydrates with the objective to increase total yield and mango quality. The pruning method involved the removal of young yellow coloured twigs as soon as they appeared at each flush period. This one-year trial showed that the yield of treated trees was similar to that of control trees but individual fruit weight was greater. Moreover, some fruiting sites were stimulated and overall tree functioning was more homogeneous, in terms of phenology and successions of flushes. The pruned trees set delayed vegetative flush that led to delayed flowering and by consequence to delayed fruit maturation and harvest. This thinning cut of young flushes decreased canopy density, with limited branching. These results could bring about the development of new orchard management practices leading to orientated production of good standard quality mangoes. Ongoing studies aim at adapting this thinning cut procedure to other cultivars in various sites.

Fruit development, not GPP, drives seasonal variation in NPP in a tropical palm plantation

We monitored seasonal variations in net primary production (NPP), estimated by allometric equations from organ dimensions, gross primary production (GPP), estimated by the eddy covariance method, autotrophic respiration (R(a)), estimated by a model, and fruit production in a coconut (Cocos nucifera L.) plantation located in the sub-tropical South Pacific archipelago of Vanuatu. Net primary production of the vegetative compartments of the trees accumulated steadily throughout the year. Fruits accounted for 46% of tree NPP and showed large seasonal variations. On an annual basis, the sum of estimated NPP (16.1 Mg C ha(-1) year(-1)) and R(a) (24.0 Mg C ha(-1) year(-1)) for the ecosystem (coconut trees and herbaceous understory) closely matched GPP (39.0 Mg C ha(-1) year(-1)), suggesting adequate cross-validation of annual C budget methods. However, seasonal variations in NPP + R(a) were smaller than the seasonal variations in GPP, and maximum tree NPP occurred 6 months after the midsummer peak in GPP and solar radiation. We propose that this discrepancy reflects seasonal variation in the allocation of dry mass to carbon reserves and new plant tissue, thus affecting the allometric relationships used for estimating NPP.

MODELING THE EFFECTS OF FRUIT LOAD, SHADE AND PLANT WATER STATUS ON COFFEE BERRY GROWTH AND CARBON PARTITIONING AT THE BRANCH LEVEL

Preliminary results of coffee berry growth modeling at the branch level are presented. The model, RAMCAF, is based on an existing model developed for peach. Parameters such as light extinction within the coffee tree canopy and potential fruit and shoot growth rates were derived from an experiment conducted over a period of two years on dwarf arabica coffee trees in Costa Rica with varying fruit loads and contrasting light regimes. Equations of leaf fall versus time as well as net photosynthesis versus photosynthetically active radiation were also obtained from experimental data. Simulations illustrate over the production cycle the effects of fruit load, level of shade and plant water status on fruit growth and carbon partitioning between the vegetative and reproductive branch compartments. Future developments such as coupling RAMCAF with a 3-dimensional architectural model of coffee trees to improve calculation of light interception and carbon assimilation are proposed. (Resume d'auteur)

Tracking chlordane compositional and chiral profiles in soil and vegetation

The cycling of chlordane and other persistent organic pollutants through the environment must be comprehensively elucidated to assess adequately the human health risks posed from such contaminants. In this study the compositional and chiral profiles of weathered chlordane residues in the soil and vegetative compartments were investigated in order to provide details of the fate and transport of this persistent pesticide. Zucchini was planted in a greenhouse in three bays containing chlordane-contaminated soil. At harvest the vegetation and soil were extracted and analyzed for chlordane content using chiral gas chromatography/ion trap mass spectrometry. Both achiral and chiral chlordane components were quantified. The chlordane concentration in the rhizosphere (soil attached to roots) was significantly less than that in the bulk soil. However, the enantiomeric ratio of the chiral components and overall component ratios had changed little in the rhizosphere relative to the bulk soil. Significant levels of chlordane were detected in the vegetation, the amount varying in different plant tissues from a maximum in roots to a minimum in fruit. In addition to the chlordane concentration gradient in plant tissues, significant shifts in compositional profile, as indicated by the component ratios, and in chiral profile, as indicated by the enantiomeric ratio, of the contaminant were observed in the plant tissues. The data indicate that abiotic processes dominate the transport of the chlordane components through the soil to the plant. This is the first report of the effect of rapid biotic processes within the plant compartment on chlordane compositional and chiral profiles.

The physiology of micronutrient homeostasis in field crops

Plants have developed a number of transport mechanisms to control the acquisition, partitioning and deposition of the micronutrients iron, copper, zinc and manganese. This control is important because the plants must obtain adequate levels of these essential nutrients for both vegetative and reproductive tissues, while at the same time preventing excess accumulation. Points of physiological control include various root-system processes, movement and partitioning along the xylem pathway, temporary storage in vegetative compartments, and mobilization via the phloem pathway. The regulation of these control points is not fully understood, although it appears that certain functions may be influenced by interorgan communication. Current evidence does indicate that these processes can be controlled to various degrees; differences exist not only between species, they can also vary temporally and spatially within a given plant. Because this regulatory variability exists, it would appear that enhancing the micronutrient density of edible plant components through the manipulation of physiological processes is an achievable goal.

Lead contamination of the roadside ecosystem.

The atmospheric, edaphic, and vegetative components of the roadside ecosystem contain elevated levels of lead originating from the combustion of lead containing gasolines by motor vehicles. The size of this ecosystem approximates 3.04 X 107 hectares (118,000 square miles) in the United States. Recent evidence has greatly refined our understanding of the distribution and localization of lead in the roadside environment. This paper is a representative review of some of this recent evidence. Vehicles release approximately 80 mg of lead/km to the atmospheric compartment in the form of inorganic lead salts ranging in size from 1 to 5 µ. Lead content of roadside atmospheres may be elevated 2-20 times non-roadside atmospheres. Sedimentation from the atmospheric compartment results in lead contamination of the soil and vegetative compartments. Lead in the upper 5 cm of the soil profile may be elevated 30 times non-roadside soil within a few m of a street or highway. The soil lead is largely bound by organic matte...