Foliage Concentrations Research Articles

Frequency of Endophytic Bacteria in Roots and Foliage of Brachiaria Humídicola Cv. Humidicola (Rendle) Schweick in Soil with Arsenic Presence

The objective of this study was to correlate the presence of arsenic in roots and stems of Brachiaria humidicola cv. humidicola (Rendle) Schweick grown in cattle areas of the San Jorge subregion and the population density of endophytic bacteria in roots and foliage with the presence of this metal. Samples of soil, roots and stems of B. humicola grass were collected and characterized for arsenic concentration in roots and foliage and the presence of endophytic bacteria (CFU/g tissue). The results show the presence of arsenic concentrations in roots and stems above the values established at national and international level. Likewise, the presence of endophytic bacteria was found in the roots and foliage of B. humidicola, which may be contributing to the remediation and reduction of arsenic concentration from the roots to the foliage. This is the first study correlating the presence of arsenic and endophytic bacteria on cattle farms with B. humicola and the possible role of these bacteria in contributing to bioremediation of this metal in the soil and within the tissues of the pasture species.

How tree species have modified the potentially toxic elements distributed in the developed soil–plant system in a post-fire site in highly industrialized region

The biogeochemical cycles of trace elements are changed by fire as a result of the mineralization of organic matter. Monitoring the accumulation of trace elements in both the environment and the tree biomass during the post-fire (PF) forest ecosystem regeneration process is important for tree species selection for reforestation in ecosystems under anthropogenic pressure. We analyzed the soil concentrations of different groups of potentially toxic elements (PTEs), including beneficial (Al), toxic (Cd, Cr, Pb), and microelements (Cu, Mn, Ni, Zn), and their bioaccumulation in the tree species (Pinus sylvestris, Betula pendula, Alnus glutinosa) biomass introduced after a fire in a forest weakened by long-term emissions of industrial pollutants. The results indicated no direct threat from the PTEs tested at the PF site. The tree species introduced 30 years ago may have modified the biogeochemical cycles of the PTEs through different strategies of bioaccumulation in the belowground and aboveground biomass. Alder had relatively high Al concentrations in the roots and a low translocation factor (TF). Pine and birch had lower Al concentrations in the roots and higher TFs. Foliage concentrations and the TF of Cd increased from alder to pine to birch. However, the highest concentration and bioaccumulation factor of Cd was found in the alder roots. The concentrations of Cr in the foliage and the Cr TFs in the studied species increased from pine to birch to alder. Higher concentrations of Cu and Ni were found in the foliage of birch and alder than of pine. Among the species, birch also had the highest Pb and Zn concentrations in the roots and foliage. We found that different tree species had different patterns of PTE phytostabilization and ways they incorporated these elements into the biological cycle, and these patterns were not dependent on fire disturbance. This suggests that similar patterns might also occur in more polluted soils. Therefore, species-dependent bioaccumulation patterns could also be used to design phytostabilization and remediation treatments for polluted sites under industrial pressure.

Propagating Uncertainty in Predicting Individuals and Means Illustrated with Foliar Chemistry and Forest Biomass

Quantifying uncertainty is important to establishing the significance of comparisons, to making predictions with known confidence, and to identifying priorities for investment. However, uncertainty can be difficult to quantify correctly. While sampling error is commonly reported based on replicate measurements, the uncertainty in regression models used to estimate forest biomass from tree dimensions is commonly ignored and has sometimes been reported incorrectly, due either to lack of clarity in recommended procedures or to incentives to underestimate uncertainties. Even more rarely are the uncertainty in predicting individuals and the uncertainty in the mean both recognized for their contributions to overall uncertainty. In this paper, we demonstrate the effect of propagating these two sources of uncertainty using a simple example of calcium concentration of sugar maple foliage, which does not require regression, then the mass of foliage and calcium content of foliage, and finally an entire forest with multiple species and tissue types. The uncertainty due to predicting individuals is greater than the uncertainty in the mean for studies with few trees—up to 30 trees for foliar calcium concentration and 50 trees for foliar mass and calcium content in the data set we analyzed from the Hubbard Brook Experimental Forest. The most correct analysis will take both sources of uncertainty into account, but for practical purposes, country-level reports of uncertainty in carbon stocks can safely ignore the uncertainty in individuals, which becomes negligible with large enough numbers of trees. Ignoring the uncertainty in the mean will result in exaggerated confidence in estimates of forest biomass and carbon and nutrient contents.

Oil Palm Nutrient Mapping Using Multispectral Drone

Unmanned Aerial Vehicle (UAV) is one of the platforms that have recently proven profitable in agriculture, despite being more commonly used as a carriage platform. Nevertheless, the use of UAVs for mapping promotes precision agriculture. Foliage mapping and nutrient mapping are examples of mapping techniques that are beneficial for oil palm. Assessing the condition and distribution of nutrient content is essential for plantation management to monitor the health of the trees, identify potential problems such as nutrient deficiency or pest infestation, and optimise management practices for higher yields. Therefore, this study aims to produce nutrient content information from UAV and spectroradiometer data. Compact remote sensing sensors operating at visible (RGB) (0.4-0.7 micrometre), Near Infra-red (NIR) (0.7-1.2 micrometre), thermal infrared (TIR) and Long-wave Infrared (LWIR) bands (7-14 micrometre) were used in this study to determine the concentration of foliage content in the oil palm plantation. Nutrient elements such as Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), and Magnesium (Mg) were detected from the foliar content as indicated in the 17th frond of oil palm leaves. This study successfully developed a method for identifying and quantifying the nutrient content of oil palm plantations using a drone platform. This study would aid in predicting oil palm production and provide farm owners and managers with valuable decision-making information.

Soil change and broadleaf tree growth 10 years after wood ash and brash co-application to a clearfelled lowland conifer site in Britain

Abstract Wood ash use, to raise pH and replace nutrients lost through forest harvesting, is well regulated in Scandinavia and Canada, but not yet in the UK. This experiment applied granulated wood ash from mixed tree thinnings to a lowland clay mineral soil at ~2.3 t ha−1 dose rate, after clearfell of western hemlock (Tsuga heterophylla (Raf.) Sarg.). With brash (~56 t ha−1 dry weight) as N resource, a 4 × 4 matrix of ash only, ash + brash, brash only and control treatments were planted with oak seedlings (Quercus robur L.). Soil survey was undertaken before ash application and followed over 10 years. By year 2, self-sown grass was dominant in the control and ash plots, and birch (Betula pendula, Roth.) was present across all treatments by year 4. In year 10, oak height was 25–29 per cent greater in brash and ash + brash plots, with DBH increased >20 per cent over the controls. Birch DBH was greater by 30 per cent in brash plots but was over 50 per cent in the ash + brash plots. Foliar concentrations of Ca, K and P significantly increased with ash addition in both oak and birch, as Al, Mn, Fe and Cr decreased. Soil pH (CaCl2) was reduced in all treatments in year 2 likely due to nitrification, during organic matter and needle breakdown, but recovered 8 years later to be significantly highest in ash and ash + brash plots. Mg, K, Ca, Na, Ba and S concentrations were higher in ash plot soils, but soil organic matter, total carbon and total nitrogen declined due to mineralization and uptake by grass and trees. Wood ash addition did not significantly increase heavy metal concentrations in either soil or foliage. In the long term, wood ash aided soil recovery and promoted tree growth in combination with the brash – it could be beneficial for tree growth after thinning/coppicing on heavy mineral soils, with the prerequisite of an existing ground cover. Aim To quantify the effects of wood ash and brash addition over time to soils and tree growth after conifer clearfelling on a lowland clay soil site.

Influence of Nano-Chitosan Loaded with Potassium on Potassium Fractionation in Sandy Soil and Strawberry Productivity and Quality

Under sandy soil conditions, increasing the efficiency of potassium (K) fertilizers is considered to be a major limiting factor for improving the productivity and quality of fruit crops. In this context, utilizing nanotechnology has emerged as a novel technique to increase the efficiency of K applications. In our study, two field trials were conducted, in two consecutive seasons (2019/2020 and 2020/2021), to compare the effects of nano-chitosan loaded with K as a foliar treatment with those of conventional soil applications of K on plant growth, yield, and quality of strawberry plants grown in sandy soil. Strawberry plants were treated with 12 different treatments, which were replicated three times in a randomized complete block design in each growing season. Potassium sulfate (K2SO4, 48% K2O) was applied to the soil at a rate of 150.0 kg acre−1 (recommended rate, 100%). Meanwhile, the spraying of nano-chitosan loaded with K was applied at 1000 mg L−1 as a control. In addition, K2SO4 was applied either individually or in combination at the rate of 112.5 or 75.0 kg acre−1 with four nano-chitosan-K dosages (250, 500, 750, and 1000 mg L−1). After harvesting, soil samples were collected and prepared to determine K fractions. As well, plant samples were collected to determine the vegetative growth parameters and the foliage content of NPK and chlorophyll. Eventually, the yield traits and quality parameters were evaluated. A principal component analysis was conducted to determine the interrelationships of the treatments’ averages and their effects on yield components and quality traits. A combined analysis was performed for the two studied seasons and the values were the mean of six replications. The results indicated that the application of common K fertilizer (150.0 kg K2SO4 acre−1) resulted in the maximum increase in soluble and exchangeable K in the soil, which was comparable to those observed with 112.5 kg K2SO4 acre−1 + 1000 mg L−1 nano-chitosan-K and 112.5 K2SO4 acre−1 + 750 mg L−1 nano-chitosan-K. The total yield, marketable yield, and fruit firmness were all significantly increased by the latter two treatments compared to the control group. Furthermore, plots treated with 112.5 kg K2SO4 acre−1 + 1000 mg L−1 nano-chitosan-K significantly increased the total soluble solids, vitamin C levels, acidity, total sugar, and anthocyanin levels in strawberry fruits. In conclusion, under sandy soil conditions, the utilization of nanoparticles could be an indispensable tool for manipulating fertilization management when cultivating strawberries. The K status of the soil was improved by applying 75% of the recommended dose of mineral K in combination with 1000 or 750 mg L−1 of nano-chitosan-K, without compromising strawberry yield or quality.

The Effects of Two Organic Soil Amendments, Biochar and Insect Frass Fertilizer, on Shoot Growth of Cereal Seedlings

To mitigate the environmental harm associated with high-input agriculture, arable farmers are increasingly required to maintain productivity while reducing inputs of synthetic fertilizers. Thus, a diverse range of organic products are now being investigated in terms of their value as alternative fertilizers and soil amendments. This study used a series of glasshouse trials to investigate the effects of an insect frass-based fertilizer derived from black soldier fly waste [HexaFrass™, Meath, Ireland] and biochar on four cereals grown in Ireland (barley, oats, triticale, spelt) as animal feed and for human consumption. In general, the application of low quantities of HexaFrass™ resulted in significant increases in shoot growth in all four cereal species, along with increased foliage concentrations of NPK and SPAD levels (a measure of chlorophyll density). These positive effects of HexaFrass™ on shoot growth were observed, however, only when a potting mix with low basal nutrients was used. Additionally, excessive application of HexaFrass™ resulted in reduced shoot growth and, in some cases, seedling mortality. The application of finely ground or crushed biochar produced from four different feedstocks (Ulex, Juncus, woodchip, olive stone) had no consistent positive or negative effects on cereal shoot growth. Overall, our results indicate that insect frass-based fertilizers have good potential in low-input, organic, or regenerative cereal production systems. Based on our results, biochar appears to have less potential as a plant growth promoting product, but could be used as a tool for lowering whole-farm carbon budgets by providing a simplistic means of storing carbon in farm soils.

Seasonal variation of mercury concentration of ancient olive groves of Lebanon

Abstract. This study investigates the seasonality of the mercury (Hg) concentration of olive tree foliage, an iconic tree of the Mediterranean basin. Hg concentrations of foliage, stems, soil surface, and litter were analyzed on a monthly basis in ancient olive trees growing in two groves in Lebanon, Bchaaleh and Kawkaba (1300 and 672 m a.s.l. respectively). A significantly lower concentration was registered in stems (∼7–9 ng g−1) in comparison to foliage (∼35–48 ng g−1) in both sites, with the highest foliage Hg concentration in late winter–early spring and the lowest in summer. It is noteworthy that olive fruits also have low Hg concentrations (∼7–11 ng g−1). The soil has the highest Hg content (∼62–129 ng g−1) likely inherited through the cumulated litter biomass (∼63–76 ng g−1). A good covariation observed between our foliage Hg time series analysis and those of atmospheric Hg concentrations available for southern Italy in the western Mediterranean basin confirms that mercury pollution can be studied through olive trees. Spring sampling is recommended if the objective is to assess the trees' susceptibility to Hg uptake. Our study draws an adequate baseline for the eastern Mediterranean and the region with similar climatic inventories on Hg vegetation uptake, in addition to being a baseline to new studies on olive trees in the Mediterranean to reconstruct regional Hg pollution concentrations in the past and present.

‘Gvardeets’: a new awnless brome (<i>Bromorsis inermis</i>) cultivar developed in Tyumen Province

Background. Awnless brome (Bromopsis inermis (Leyss.) Holub) is a perennial herbaceous plant used as feed in animal husbandry, for phytomelioration, and as a component of grass mixtures to make a durable natural cover for landscaping. Studying the genetic diversity of this species and selecting the best accessions will help to develop new cultivars capable of productive longevity.Materials and methods. In 2017, a new cultivar of B. inermis called ‘Gvardeets’ was submitted to the State Variety Trials. It was developed using chemical mutagenesis followed by multiple selection from cv. ‘Sverdlovsky 38’ at the Research Institute of Agriculture for the Northern Trans-Ural Region, a branch of Tyumen Scientific Center. During the growing seasons of 2012–2020, the cultivar was compared in the field according to the main productivity indicators with the reference cvs. ‘Langepas’ and ‘Sverdlovsky 38’. Observations were performed according to the guidelines for the study of fodder crops.Results and conclusions. The new cultivar ‘Gvardeets’ is mid-season: it takes 50–60 days for its plants to develop from spring regrowth to the beginning of mowing and 95–110 days to harvesting. The plants are erect, 115–145 cm high; foliage content is 38–50%. Protein content in dry matter is 7.0–12.0%; fiber content, 28.2–34.0%. It has a good yield: the harvest of green mass for 9 years averaged 22.8 t/ha; hay, 7.7 t/ha; seeds, 0.19 t/ha, which is higher the original cv. ‘Sverdlovsky 38’ ( ) by 13, 12 and 16% and the productive cv. ‘Langepas’ by 6, 7 and 5%, respectively. It is winter-hardy, resistant to lodging, technology-friendly, and well adaptable to adverse environmental conditions, which ensures its high value for practical use. It was designed for hayfields and pastures. According to the results of the State Variety Trials, in 2021 it was commercialized for the Volga-Vyatka (4), West Siberian (10), and East Siberian (11) regions of Russia.

Viscotoxin and lectin content in foliage and fruit of Viscum album L. on the main host trees of Hyrcanian forests

Mistletoe (Viscum album L.) is a hemiparasitic plant that absorbs water and nutrients from the host tree. Mistletoe contains two groups of cytotoxic, immunomodulatory and antitumor proteins, viscotoxins and lectins. This study evaluated the quantity and quality of viscotoxins and total lectins in the stems with leaves (foliage) and fruit of mistletoe on Parrotia persica and Carpinus betulus in September with immature green berries and in December with mature white berries. Viscum album L. plants were harvested from host species located in the Hyrcanian forests of Iran in 2019. The highest level of viscotoxins was detected in the December foliage of V. album settled on C. betulus (9.25 mg/g dry weight [DW]), and the highest content of lectins was found in the December foliage of V. album settled on P. persica (0.79 mg/g DW) and C. betulus (0.73 mg/g DW) respectively. The immature green berries of V. album from both host species contained much higher concentrations of viscotoxins and lectins than the mature white berries. Four isoforms of viscotoxins, viscotoxin A1, A2, A3 and B could be identified in all samples of both host species. Viscotoxin A3 was the predominant viscotoxin isoform followed by viscotoxin A1.

Foliar Application of Salicylic Acid and DA-6 on Swithgrass (Panicum virgatum L.) Grown in Pb-Contaminated Soil; Implications for Phytoextraction

ABSTRACT Lead (Pb) soil contamination is widespread and poses a threat to human health. Even chronic exposure to low levels of Pb contaminated soils is potentially harmful to organisms. Remediation of Pb-contaminated soil can be accomplished through phytoextraction, a technique that uses plants and associated soil microorganisms. The North American native switchgrass (Panicum virgatum L.), a second-generation bioenergy crop was used in this study due to its ability to produce high biomass and grow on marginal lands. In this study the effects of exogenous foliar application of the plant growth regulators diethyl aminoethyl hexanoate (DA-6) and salicylic acid (SA) were examined separately but in conjunction with the soil-fungicide propiconazole and soil chelate nitrilotriacetic acid (NTA) in order to optimize phytoextraction of Pb. Plants were grown under controlled conditions using highly Pb-contaminated (5802.5 mg kg−1) soil derived from a superfund site. Foliar application of the plant growth regulator DA-6 resulted in significantly higher Pb concentrations in the foliage of plants compared to Control plants. The DA-6 did, however, not improve plants dry mass (DM). Foliar application of salicylic acid resulted in significantly greater DM of the foliage compared to Control plants. The DM of plants treated with foliar application of salicylic acid was 46% higher than those of Control plants. Foliar application of salicylic acid did not improve significantly Pb concentration of foliage compared to Control plants. The findings reported in this study will potentially improve phytoextraction by switchgrass grown in Pb contaminated soils.

Evaluation of Chelating Agents Used in Phytoextraction by Switchgrass of Lead Contaminated Soil.

Soil lead (Pb) contamination is a recognized environmental and global health problem. Phytoextraction of Pb using switchgrass (Panicum virgatum L.), a second-generation biofuel crop, is typically enhanced by soil chelation. The effectiveness of four different chelating agents, phytic acid (inositol hexaphosphate), citric acid, NTA (nitrilotriacetic acid), and EDTA (ethylenediaminetetraacetic acid) was examined in pot culture. Plants treated with EDTA (1 mM) showed significantly higher shoot Pb concentrations compared to control plants and plants treated with other chelates. Lead-solubility following phytoextraction was examined by soil washing using 0.01 and 0.05 M acetic acid as an extractant solution revealed no significant differences in Pb concentrations in soil among different chelate treatments and control. Furthermore, the effects of different concentrations (1, 2, 5 and 10 mM) of NTA on Pb phytoextraction of switchgrass were examined. Plants receiving 5 mM and 10 mM NTA had significantly higher foliage concentrations of Pb compared to plants treated with lower levels (1 and 2 mM) of NTA. Moreover, the effect of NTA application alone was significantly improved by a combined application of Triton X-100, an alkyl polyglucoside (APG); the Pb concentration in the foliage of switchgrass was more than doubled when treated with NTA combined with APG. The use of NTA combined with APG has great potential in improving phytoextraction efficiencies of switchgrass on Pb-contaminated soils.

A maceration treatment of leucaena foliage improves its nutritional value by reducing mimosine concentration

Giant leucaena produces high dry matter yields but the foliage contains mimosine, a non-protein amino acid that is toxic to animals, especially non-ruminants. Reducing mimosine concentration in foliage following harvesting may allow for greater use of Giant leucaena and mitigate the negative aspects of higher mimosine concentration in some varieties. We evaluated two methods for post-harvest treatment of foliage of a highly productive interspecific hybrid variety ‘KX2’ for reducing mimosine concentration: (i) maceration treatment; and (ii) extraction with 0.1 N HCl. Mimosine as a percentage of leaf dry matter ranged from less than 1% DM to around 3% DM. Although both methods reduced mimosine concentration, extraction by 0.1 N HCl also reduced gross energy, protein and carbohydrate concentrations of leucaena foliage. The maceration treatment, on the other hand, caused little reduction in crude protein and crude fat concentrations but markedly increased the carbohydrate concentration. ADF and NDF concentrations were also reduced as a result of maceration treatment. The estimated gross energy concentration in macerated foliage was not significantly lower than in unprocessed foliage. A suitable mechanical method for post-harvest maceration of leucaena foliage, e.g. a wood-chipping machine, could be used to reduce mimosine concentration in the foliage, making it safer for feeding to livestock and enhancing the feed value, especially for non-ruminants. These methods should be tested by conducting feeding studies to determine the possible benefits in animal performance from feeding macerated foliage.

Feasibility Study of Wood-Leaf Separation Based on Hyperspectral LiDAR Technology in Indoor Circumstances

Wood–leaf separation aiming at classifying LiDAR points into wood and leaf components is one of the most important genres for improving leaf area index estimation and forestry survey accuracy. The wood return signals could artificially increase the apparent foliage content, which needs to be screened out for deriving vital tree attributes accurately. Previous research works tended to use intensity, waveform, and geometric information extracted from a single wavelength LiDAR for wood–leaf separation. This article employs a revised hyperspectral LiDAR (HSL) to obtain spatial and ultrawide spectral data simultaneously. We also propose a simple three steps method to separate wood and leaf components based on HSL spatial and spectral measurements under the laboratory circumstances. First, the preprocessing is conducted to acquire 3-D spatial information and the multiband laser pulse reflectance for further separation. Second, preliminary separation (band division, key feature parameter calculation, and judgment) is implemented based on reflectance. Third, we employ K-Nearest Neighbor (KNN) method to enhance separation results based on preliminary separation results and spatial features and then update the results by recorrection. Then, 3-D reconstruction is accomplished by fusing wood–leaf separation results. The experimental results demonstrate that the proposed method can separate wood and leaf components with high accuracy and indicate tree attributes straightforwardly.

Carbon content and allometric models to estimate aboveground biomass for forest areas under restoration

Maximizing carbon sequestration is crucial to mitigate climate change and indicates that the restoration technique used was effective. To quantify carbon stock over time on areas being restored, suitable allometric equations are needed. These equations are lacking for the Atlantic forest, lacking even more for restoration sites, and rare for restoration areas implemented with the active method, technique often used to restore Atlantic forest areas. Thus, the objective of this study was 3‐fold. First, to provide an equation to estimate aboveground biomass for 5‐year‐old Atlantic forest under restoration implemented with the active method. Second, to determine carbon content for the branch, stem, and foliage pools for those areas. Third, to present biomass, carbon content, and carbon stock benchmarks for 5‐year‐old areas under restoration implemented with the active method. Three sites were sampled with nine plots each, measuring tree height and diameter. One subplot was established in each plot, and all trees within it were harvested and had fresh weight measured and samples were taken to the laboratory to dry weight and carbon content determination. Ten models estimating biomass were fitted and tested. Mean carbon content in foliage, branch, stem, and the weighted average were 44.8, 44.5, 45.8, and 45.3%, respectively. Mean biomass and carbon stock were 20.19 ± 0.146 Mg/ha and 9.73 Mg C/ha. We concluded that the equation that we provide is precise, and very necessary to estimate biomass for young restoration areas at the Atlantic forest.

Biomonitoring of Mercury Contamination in Poland Based on Its Concentration in Scots Pine (Pinus sylvestris L.) Foliage.

This work evaluates current mercury (Hg) contamination in Poland, represented by the Hg concentrations in Scots pine foliage. Samples were collected over 295 investigation plots in monitoring grids throughout Poland, from pines aged between 12 and 147 years. Analyses were conducted with consideration of bioclimatic factors and soil properties. Concentrations in the pine foliage did not exceed the values characteristic of an ecosystem unaffected by industrial pollution, ranging from 0.0032 to 0.0252 mg kg−1 dry mass. However, pine stands located in western and central Poland, and in the northwest near the Baltic Sea, exhibited higher Hg concentrations in foliage than in eastern regions. Hg content in foliage depends on the mean temperature of the driest quarter, as well as on Hg content in soils. This indicates that the periods of drought observed in recent years in Poland may affect Hg concentrations in pine foliage.

Effects of Exogenous Application of Plant Growth Regulators (SNP and GA3) on Phytoextraction by Switchgrass (Panicum virgatum L.) Grown in Lead (Pb) Contaminated Soil

Soil lead (Pb) contamination is a major environmental and public health risk. Switchgrass (Panicum virgatum), a second-generation biofuel crop, is potentially useful for the long-term phytoremediation and phytoextraction of Pb contaminated soils. We evaluated the efficacy of a coordinated foliar application of plant growth regulators and soil fungicide and a chelator in order to optimize phytoextraction. Plants were grown in soil culture under controlled conditions. First, three exogenous nitric oxide (NO) donors were evaluated at multiple concentrations: (1) S-nitroso-N-acetylpenicillamine (SNAP); (2) sodium nitroprusside (SNP); and (3) S-nitrosoglutathione (GSNO). Second, the effect of SNP (0.5 μM) was examined further with the model chelate EDTA and the soil fungicide propicanazole. Third, a combined foliar application of SNP and gibberellic acid (GA3) was examined with EDTA and propicanazole. The soil application of propiconazole (a broad-spectrum fungicides) reduced AMF colonization and allowed greater Pb phytoextraction. The foliar application of SNP resulted in similar concentrations of Pb (roots and foliage) to plants that were challenged with chelates and soil fungicides. The combined foliar application of SNP and GA3 resulted in significantly greater average Pb concentration (243 mg kg−1) in plant foliage in comparison to control plants (182 mg kg−1) and plants treated with GA3 alone (202 mg kg−1). The combined foliar application of SNP and GA3 resulted in the greatest phytoextraction efficiency and could therefore potentially improve phytoextraction by switchgrass grown in Pb contaminated soils.

How the capacity of bedrock to collect dust and produce soil affects phosphorus bioavailability in the northern Appalachian Mountains of Pennsylvania

AbstractMore above‐ground biomass (kg m−2) grows in the northern Appalachian Mountains (USA) in forests on shale than on sandstone at all landscape positions other than ridgetops. This has been tentatively attributed to physical (rather than chemical) attributes of the substrates, such as elevation, particle size, and water capacity. However, shales have generally similar phosphorus (P) concentrations to sandstones and, in the Valley and Ridge province, they erode more quickly. This led us to hypothesize that faster replenishment of the lithogenic nutrient P in shale soils through erosion + soil production could instead control the differences in biomass. To test this, soils and foliage from 10 sites on shales and sandstones in the northern Appalachians from roughly the same elevation and aspect were analysed. We discovered that, when controlling for location, concentrations of bioavailable P in soils and P in foliage were higher and P resorbed from senescing red oak leaves was lower on slower‐eroding sandstone than on faster‐eroding shale. Lower resorption generally can be attributed to lower P limitation for trees. Further investigation of weathering and erosion on one of the sandstone–shale pairs within a larger, paired watershed study revealed that the differences in P concentrations in biomass and foliage between lithologies likely developed because sandstones act as ‘collectors’ that trap nutrients from residual and exogenous sources, while shales erode quickly and thus promote production of soil from bedrock that releases P to ecosystems. We concluded that the combined effects of differential rates of dust collection and erosion results in roughly equal biomass growing on sandstone and shale ridgetops. This work emphasizes the balance between a landscape's capacity to collect dust versus produce soil in controlling bioavailability of nutrients.

Response of Different Potato Genotypes to Drought Stress

A pot trial was established to evaluate the response of different potato genotypes to drought stress. Two potato genotypes (Demon and Hopehely) were exposed to two water levels (80% and 50% water holding capacity). The trial was replicated 16 times and 4 replications were harvested at 36 DAS, 54 DAS, 72 DAS, and 90 DAS. The results revealed that drought significantly reduced the growth and plant development of Demon (G1). Hopehely (G2) produced a higher yield in control as well as drought condition. Tuber yield positively correlated with tubers number, and root weight that was significantly higher in Hopehely under both experimental conditions. Hopehely produced a higher number of tubers (18) than Demon whereas Demon produced 11 tubers per plant. Moreover, under drought conditions, the relative water content of leaves and nitrogen content in foliage increased in Hopehely while decreased in Demon. Drought stress caused a 40% reduction in plant height and a 24.3% reduction in the number of leaves in Demon that was significantly higher than the 11% plant height reduction and 9.1% leaf count reduction in Hopehely. It was observed that the morphology of Hopehely (producing dwarf plants, fewer leaves, maintaining water content of leaves, producing more tubers) helped it to be a better drought-tolerant genotype compared to Demon.

Mapping phosphorus concentration in Mediterranean forests using different remote-sensing methods

ABSTRACT Mineral nutrition is essential for optimal plant growth. Phosphorus (P) is a relatively small component of leaf dry weight, with a concentration in plant foliage of less than 1%. Despite its low concentration, P is an essential element in plants, mainly used for energy transfer. Mapping P concentration using traditional methods is expensive and usually limited to a small area; it is time-consuming and covers only a few plant individuals or species. In this study, we demonstrate the use of remote-sensing (RS) data acquired from the feld and airborne hyperspectral sensors to predict and map the P concentration in leaves of different woody Mediterranean plant species. Comprehensive field work included leaf sampling, laboratory analyses, and spectral measurements using a visible, near-infrared and shortwave-infrared (VIS–NIR–SWIR) field spectrometer. Using different spectral configurations, we built accurate models to predict P concentration in leaf samples. The models were built using a NIR data analysis technique with the data mining software PARACUDA II. This software allowed us to identify the correlative wavelengths for P-bearing molecules in selected woody Mediterranean plant species. The hyperspectral-based model for leaf P concentration was extracted from the reflectance data acquired using a manned aircraft carrying a hyperspectral sensor (Specim AisaFenix 1 K). The model gave a reliable correlation between points extracted from the hyperspectral image and samples measured in the field. We believe that the methodology used in this study will help forest ecologists better understand the concentration of P in the foliage of woody Mediterranean plant species.