Tissue Nutrient Concentrations Research Articles

A representation of the phosphorus cycle for ORCHIDEE (revision 4520)

Abstract. Land surface models rarely incorporate the terrestrial phosphorus cycle and its interactions with the carbon cycle, despite the extensive scientific debate about the importance of nitrogen and phosphorus supply for future land carbon uptake. We describe a representation of the terrestrial phosphorus cycle for the ORCHIDEE land surface model, and evaluate it with data from nutrient manipulation experiments along a soil formation chronosequence in Hawaii. ORCHIDEE accounts for the influence of the nutritional state of vegetation on tissue nutrient concentrations, photosynthesis, plant growth, biomass allocation, biochemical (phosphatase-mediated) mineralization, and biological nitrogen fixation. Changes in the nutrient content (quality) of litter affect the carbon use efficiency of decomposition and in return the nutrient availability to vegetation. The model explicitly accounts for root zone depletion of phosphorus as a function of root phosphorus uptake and phosphorus transport from the soil to the root surface. The model captures the observed differences in the foliage stoichiometry of vegetation between an early (300-year) and a late (4.1 Myr) stage of soil development. The contrasting sensitivities of net primary productivity to the addition of either nitrogen, phosphorus, or both among sites are in general reproduced by the model. As observed, the model simulates a preferential stimulation of leaf level productivity when nitrogen stress is alleviated, while leaf level productivity and leaf area index are stimulated equally when phosphorus stress is alleviated. The nutrient use efficiencies in the model are lower than observed primarily due to biases in the nutrient content and turnover of woody biomass. We conclude that ORCHIDEE is able to reproduce the shift from nitrogen to phosphorus limited net primary productivity along the soil development chronosequence, as well as the contrasting responses of net primary productivity to nutrient addition.

Genetic variation in compensatory feeding for dietary dilution in a generalist caterpillar

Increasing the rate of food consumption is a common adaptive strategy that allows herbivores to compensate for declines in nutrient concentrations in plant tissues. Herbivores that are better able to compensate for dietary dilution may have selective advantages under nutritionally poor conditions. In order for compensatory feeding to respond to selection, there must be standing heritable variation for this trait. However, empirical data substantiating the adaptive significance and genetic variability of compensatory feeding are rare. By employing a full-sib, split-brood design, this study presents quantitative genetic analyses on the nutrient consumption rates of the generalist caterpillar, Spodoptera exigua, raised on semi-synthetic diets differing in nutrient concentrations. When encountering a diluted diet, caterpillars exhibited a compensatory increase in food consumption rate, but the extent of this increase was not sufficient to fully compensate for dietary dilution. A significant gene-environment interaction for consumption rate indicated that the capacity of caterpillars to compensate for dietary dilution varied across genotypes. The broad-sense heritability of compensatory feeding was 0.51. Caterpillar genotypes with a higher compensatory capacity suffered lower performance losses on the diluted diet than did those with a lower capacity. This study has implications for understanding how herbivores can evolutionarily respond to nutritional challenges.

Chromium from Hydrolyzed Leather Affects Soybean Growth and Nodulation

Hydrolyzed leather, obtained from industrial leather waste, is an organic nitrogenous fertilizer with a high chromium (Cr) content. Soybean crops can be adversely affected by the presence of residual Cr in soil after application of hydrolyzed leather fertilizer. The aim of this work was to assess the effect of hydrolyzed leather on Cr absorption, root development, and symbiotic nodulation of soybean plants grown on three different soils including two Lixisols and a Gleysol. These soils were previously fertilized with hydrolyzed leather at three different rates (0.0, 0.1, and 0.8 kg m−2). Soybean shoot height, root development, nodulation, and mineral nutrient concentrations in plant tissues were determined after 45 d of crop growth. The application of hydrolyzed leather significantly increased Cr content in soil and Cr uptake by plants. Surprisingly, Cr was stored mainly in the aerial part of the plants. The presence of Cr had an adverse impact on shoot dry matter (41% reduction) and number of nodules (49% reduction) per plant grown on the soil with the lowest cation exchange capacity. However, no other significant effect was observed in nodule weight, diameter, or any other measured parameters.

Yield, Fruit Quality Traits, and Leaf Nutrient Concentration of ‘Prolific’ Sapodilla Grafted onto Seedlings of 16 Sapodilla Rootstocks in Puerto Rico

Research on sapodilla (Manilkara zapota) has been very limited. A field study was conducted to determine the yield potential, fruit quality traits, leaf nutrient composition, and scion/rootstock compatibility of ‘Prolific’ sapodilla grafted onto 16 sapodilla rootstock seedlings. For this purpose, seedlings (maternal half-sibs) of cultivars Adelaide, Arcilago, Aruz, Blackwood, Blocksberg, Guilbe, Hanna, Jamaica-1, Larsen, Mendigo-1, Gallera, Morning Star, Russel, Prolific, Timothe, and Vasallo-1 were used as rootstock seedlings and evaluated during 7 years of production at Isabela, PR. Year showed a significant effect on the number of fruit per hectare, yield, individual fruit weight, fruit length and diameter, and total soluble solids. Rootstock seedlings had a significant effect on the number of fruit per hectare, yield, and individual fruit weight but had no effect on other fruit traits. The year × rootstock interaction was not significant for any of the variables measured in the study. Rootstock seedlings ‘Timothe’, ‘Vasallo-1’, ‘Larsen’, and ‘Aruz’ had the highest 7-year mean for number and the yield of fruit averaging 4479 fruit/ha and 1245 kg·ha−1, respectively. ‘Timothe’ and ‘Vasallo-1’ significantly out yielded the ‘Prolific’ rootstock seedling. The number of fruit per hectare and corresponding yield obtained in this study were very low probably as the result of wind exposure, the presence of the fungus Pestalotia causing floral necrosis, or both. Scion/rootstock incompatibility was not the cause of the low yield performance of grafted trees. The average individual weight of fruit was 282 g and ranged from 264 to 303 g. Averaged over rootstock seedlings, leaf tissue nutrient concentration did not vary greatly over time. Moreover, tissue nutrient concentration was similar before and after fertilization events.

Mycorrhization affects root distribution of Lotus corniculatus and Calamagrostis epigeios in a nutrient poor heterogeneous soil in a rhizotron experiment

Plant growth can be highly dependent on symbiotic partners, such as arbuscular mycorrhizal fungi (AMF) that improve the plant's nutrient uptake. However, less is known about whether AMF can beneficially influence spatial root distribution, especially in soils with patchy nutrient concentrations. This study was conducted to evaluate root distribution and plant response of Lotus corniculatus and Calamagrostis epigeios in a heterogeneous nutrient poor soil under different mycorrhizal conditions.Heterogeneous soil conditions of a reclamation site in the Lusation mining district, consisting of a nutrient poor sandy soil with embedded large silt-clay fragments, were used for this rhizotron experiment. Treatments were non-mycorrhizal and mycorrhizal L. corniculatus and C. epigeios in sterile soil and in sterile soil with a fungal free soil solution and mycorrhizal plants in a non-sterile soil. Mycorrhizal fungi were exogenous (Funneliformis mosseae and Rhizophagus irregularis) in sterile soil and indigenous mycorrhizal fungi in non-sterile soil. Plants were grown in rhizotrons, with clay-silt fragments in a sandy soil matrix. Treatment response variables were root density, root and shoot biomass, shoot tissue nutrient concentrations, and percentage of roots in clay-silt fragments relative to total root biomass, mycorrhizal colonization and intraradical fungal alkaline phosphatase (ALP) activity.Exogenous mycorrhizal L. corniculatus plants had higher root mass density in clay-silt fragments than indigenous mycorrhizal and non-mycorrhizal plants while C. epigeios had only higher root mass density in clay-silt fragments relative to sandy soil only in exogenous mycorrhizal plants in sterile soil with soil solution. Non-mycorrhizal C. epigeios shoot biomass in sterile soil did not significantly differ from that of exogenous mycorrhizal treatments. The greatest shoot biomass for both plant species, was with the highest percentage of roots in clay-silt fragments relative to the total root system. Exogenous mycorrhizal plants of both species had highest shoot phosphorus concentrations in sterile soil with soil solution. However, intraradical fungal ALP activity was highest in indigenous mycorrhizal plants. The results indicate that mycorrhizal conditions can have a strong influence on spatial root development. The consequences are that conditions, which promote root growth, lead to more roots in nutrient rich clay-silt fragments and thus enhance plant exploitation of heterogeneously distributed soil nutrients.

Nutrimental balance in aquaponic lettuce production

This research was conducted in order to determine the best fish density for growing both fish and lettuce (Lactuca sativa L.) in aquaponics, under greenhouse conditions. Densities of 10, 15, 20 and 25 kg m-3 of tilapia (Rocky Mountain strain.) with a plant density of 25 lettuce m-2 were established in an aquaponic system. The variables measured were related to vegetative growth (fresh weight, plant height and stem diameter), nutrient content in plant tissue (N, P, K, Ca, Mg, Fe, Cu, Zn, Mn and B) and concentration of N-NO3-, P-H2PO42-, K+, Ca2+ and Mg2+ in the nutrient solution, during two aquaponic cycles of lettuce cultivation. The highest fresh lettuce weight, plant height, stem diameter, nutrients in aquaponic solution and tissue nutrients content were obtained with a fish density of 25 kg m-3. The nutrient concentration in aquaponic nutrient solution increased according to fish density. At the end of experiment (60 days after transplanting), N-NO3-, Ca2+ and Mg2+ concentration reached its highest values of 105, 38.5 and 38 mg L-1, respectively; meanwhile P-H2PO42- and K+ reached its highest concentration (15 and 14 mg L-1, respectively) between 21 and 35 days after starting the experiment. These results indicate that the aquaponic system provide only 62% of N-NO3-, 48% of P, 5% of K, 21% of Ca and 79% of Mg in relation to the Steiner Universal Nutrient Solution for hydroponics. However normal tissue nutrient content was observed, with exception of K, Ca and Cu, but no signs of nutrient deficiencies were observed in lettuce leaves.

Soybean Response to Broadcast Application of Boron, Chlorine, Manganese, and Zinc

Core Ideas Application of B, Cl, and Zn increase soybean tissue concentration of each respective nutrient. Addition of B, Cl, Mn, and Zn do not increase soybean grain yield and have a marginal impact on soybean grain quality. Soil tests for B, Cl, and Zn do not predict soybean grain yield response and no relationships exist between trifoliate B, Cl, Mn, and Zn concentration to grain yield or their respective soil tests. It is unlikely that micronutrients are needed to increase soybean grain yield. Efficient use of micronutrients can potentially increase soybean [Glycine max (L.) Merr.] grain yield and economic return. The objectives of this study were to determine the effect of broadcast application of micronutrients on soybean tissue nutrient concentration and grain yield and the relationships between soil and plant tissue tests. Three separate research trials were conducted at 35 sites from 2011 to 2014. Soybean response to Zn application was evaluated in Study 1; B, Mn, and Zn in Study 2; and B, Cl, Mn, and Zn in Study 3. Fertilizers were broadcast applied to the soil surface and incorporated prior to planting. Application of B, Cl, and Zn increased soybean trifoliate concentration of each respective nutrient but application of Mn did not. Addition of B, Cl, Mn, and Zn did not increase soybean grain yield and had a marginal impact on soybean grain quality. Application of 2.2 kg B ha−1 sometimes reduced soybean grain yield. Soil tests for B, Cl, and Zn did not predict soybean grain yield response and there were no relationships between trifoliate B, Cl, Mn, and Zn concentration to grain yield or their respective soil tests. Increased soybean grain yield did increase the removal of micronutrients, but it is unlikely that micronutrients are needed to increase soybean grain yield. Results from these studies conducted across Minnesota showed that broadcast application of B, Cl, Mn, and Zn do not increase soybean yield except for low Mn (<20 mg kg−1) where Mn application could increase soybean yield.

Identification of Nutrient Contents in Six Potential Green Biomasses for Developing Liquid Organic Fertilizer in Closed Agricultural Production System

The use of solid organic fertilizer in closed agricultural production system must be combined with foliar application to improve fertilizing effectiveness. Nutrient contents in tissues of green biomass determine the quality of liquid organic fertilizer. Six potential green biomasses, Tithonia diversifolia (Hemsl.) A. Gray, Gliricidia sepium (Jacq.) Kunth ex Walp., Leucaena leucocephala (Lamk.) de Wit, Ageratum conyzoides L., Eichhornia crassipes (Mart.) Solms, and banana corms were identified its nutrient contents. Samples were dried at 60 o C for 48 hours, grinded, analyzed for N, P, K, Ca -ex , Mg -ex , C, cellulose and lignin contents. Results indicated that T. diversifolia and A. conyzoides had the highest N content compared to other biomasses. A. conyzoides had the highest P content, followed by T. diversifolia . A. conyzoides had the highest K content, followed by G. sepium . The highest Ca- ex content was in L. leucocephala , followed by A. conyzoides . The highest Mg -ex content was found in A. conyzoides , followed by L. leucocephala . The highest C content was found in E.crassipes , followed by G. Sepium. T. diversifolia had the highest cellulose content, followed by E.crassipes . Lignin content of all biomasses was similar. Lastly, E.crassipes had the highest C/N compared to other biomass, and both T. diversifolia and A. conyzoides had the lowest C/N. It is concluded that A. conyzoides is the most promising green biomass for production of liquid organic fertilizer, followed by T. diversifolia and G. sepium.

Nutrient Distribution and Content in Plant Tissue, Forest Floor, and Litterfall in Four Pioneer Stands on Volcano Mt. Showa-Shinzan.

Nutrient Distribution and Content in Plant Tissue, Forest Floor, and Litterfall in Four Pioneer Stands on Volcano Mt. Showa-Shinzan.

Relationships between abiotic environment, plant functional traits, and animal body size at Mount Kilimanjaro, Tanzania.

The effect-response framework states that plant functional traits link the abiotic environment to ecosystem functioning. One ecosystem property is the body size of the animals living in the system, which is assumed to depend on temperature or resource availability, among others. For primary consumers, resource availability may directly be related to plant traits, while for secondary consumers the relationship is indirect. We used plant traits to describe resource availability along an elevational gradient on Mount Kilimanjaro, Tanzania. Using structural equation models, we determined the response of plant traits to changes in precipitation, temperature and disturbance with and assessed whether abiotic conditions or community-weighted means of plant traits are stronger predictors of the mean size of bees, moths, frugivorous birds, and insectivorous birds. Traits indicating tissue density and nutrient content strongly responded to variations in precipitation, temperature and disturbance. They had direct effects on pollination and fruit traits. However, the average body sizes of the animal groups considered could only be explained by temperature and habitat structure, not by plant traits. Our results demonstrate a strong link between traits and the abiotic environment, but suggest that temperature is the most relevant predictor of mean animal body size. Community-weighted means of plant traits and body sizes appear unsuitable to capture the complexity of plant-animal interactions.

Effect of biochar derived from faecal matter on yield and nutrient content of lettuce (Lactuca sativa) in two contrasting soils

BackgroundFaecal matter biochar offers an interesting value proposition where the pyrolysis process guaranties a 100% pathogen elimination, as well as significant reduction in transport and storage weight and volume. Therefore, to evaluate the effect of (1) biochar produced from dried faecal matter from household based septic tanks, and (2) N fertilizer, as well as their interaction on yield and nutrient status of lettuce (Lactuca sativa), lettuce was grown over two growing cycles under glasshouse on two contrasting soils amended once at the start with factorial combination of faecal matter biochar at four rates (0, 10, 20 and 30 t ha−1) with 0, 25 and 50 kg N ha−1 in randomized complete block design.ResultsFor both soils, maximum fresh yields were recorded with biochar and combined application of biochar with N treatments. However, the greatest biochar addition effects (with or without N) with regard to relative yield were seen in less fertile sandy loam soil. We have also observed that faecal matter biochar application resulted in noticeable positive residual effects on lettuce yield and tissue nutrient concentrations in the 2nd growing cycle. For both soils, most nutrients analyzed (N, P, K, Mg, Cu and Zn) were within or marginally above optimum ranges for lettuce under biochar amendment.ConclusionsThe application of faecal matter biochar enhances yield and tissue nutrient concentrations of lettuce in two contrasting soils, suggesting that faecal matter biochar could be used as an effective fertilizer for lettuce production at least for two growing cycles. Moreover, the conversion of the faecal matter feedstock into charred product may offer additional waste management benefit as it offers an additional (microbiologically safe) product compared to the more common co-composting.

케라틴 아미노산 비료 시비에 따른 크리핑 벤트그래스의 생육과 품질 변화

Amino acids in the plant were intermediate metabolites which produced by uptake and assimilation of nitrogen and these extracts which gained by bio-chemical digestion from protein of plant or animal were a source of functional fertilizer. This study was conducted to evaluate effects of keratin amino acid fertilizer (KAF) gained from animal hair or hoof on changes of turfgrass quality and growth by investigating turf color index, chlorophyll index, shoot number, clipping yield, and nutrient content in the turfgrass tissue. Treatments were designed as follows; non-fertilizer (NF), compound fertilizer (CF), keratin amino acid fertilizer treatments [CF + KAF 0.26 ml m −2 (CKF), CF + KAF 0.52 ml m −2 (2CKF)], and only keratin amino acid fertilizer treatment (KF). Shoot number, clipping yield, and nitrogen uptake of KF were higher than those of CF. As compared with CF, soil chemical properties, turf color index, chlorophyll index and clipping yield of keratin amino acid fertilizer were not significant, but shoot number and uptake of N and K were increased significantly. These results show that the application of keratin amino acid fertilizer increased shoot number and growth by increased uptake of nitrogen and potassium.

Associations between omega-3 fatty acids, selenium content, and mercury levels in wild-harvested fish from the Dehcho Region, Northwest Territories, Canada

ABSTRACTTo better understand the risks and benefits of eating wild-harvested fish from the Northwest Territories, Canada, levels of total mercury (HgT) and selenium (Se) and composition of omega-3 fatty acid (n-3 FA) were measured in muscle tissue of fish harvested from lakes in the Dehcho Region, Northwest Territories, Canada. Average HgT levels ranged from 0.057 mg/kg (cisco) to 0.551 mg/kg (northern pike), while average n-3 FA concentrations ranged from 101 mg/100 g (burbot) to 1,689 mg/100 g (lake trout). In contrast to HgT and n-3 FA, mean Se concentrations were relatively similar among species. Consequently, species such as lake whitefish, cisco, and longnose sucker displayed the highest nutrient levels relative to HgT content. Levels of HgT tended to increase with fish size, while Se and n-3 FA levels were typically not associated with fork length or fish weight. Interestingly, HgT concentration was occasionally inversely related to tissue nutrient content. Significant negative correlations were observed between Hg and n-3 FA for lake trout, northern pike, and walleye. There were also significant negative correlations between Hg and Se noted for lake whitefish, cisco, and northern pike. Samples with the highest nutritional content displayed, on occasion, lower levels of HgT. This study provides valuable information for the design of probabilistic models capable of refining public health messaging related to minimizing Hg risks and maximizing nutrient levels in wild-harvested fish in the Canadian subarctic.

Nitrogen:phosphorous supply ratio and allometry in five alpine plant species.

In terrestrial ecosystems, atmospheric nitrogen (N) deposition has greatly increased N availability relative to other elements, particularly phosphorus (P). Alterations in the availability of N relative to P can affect plant growth rate and functional traits, as well as resource allocation to above‐ versus belowground biomass (M A and M B). Biomass allocation among individual plants is broadly size‐dependent, and this can often be described as an allometric relationship between M A and M B, as represented by the equation MA=αMBβ, or log M A = logα + βlog M B. Here, we investigated whether the scaling exponent or regression slope may be affected by the N:P supply ratio. We hypothesized that the regression slope between M A and M B should be steeper under a high N:P supply ratio due to P limitation, and shallower under a low N:P supply ratio due to N limitation. To test these hypotheses, we experimentally altered the levels of N, P, and the N:P supply ratio (from 1.7:1 to 135:1) provided to five alpine species representing two functional groups (grasses and composite forbs) under greenhouse conditions; we then measured the effects of these treatments on plant morphology and tissue content (SLA, leaf area, and leaf and root N/P concentrations) and on the scaling relationship between M A and M B. Unbalanced N:P supply ratios generally negatively affected plant biomass, leaf area, and tissue nutrient concentration in both grasses and composite forbs. High N:P ratios increased tissue N:P ratios in both functional groups, but more in the two composite forbs than in the grasses. The positive regression slopes between log M A and log M B exhibited by plants raised under a N:P supply ratio of 135:1 were significantly steeper than those observed under the N:P ratio of 1.7:1 and 15:1. Synthesis: Plant biomass allocation is highly plastic in response to variation in the N:P supply ratio. Studies of resource allocation of individual plants should focus on the effects of nutrient ratios as well as the availability of individual elements. The two forb species were more sensitive than grasses to unbalanced N:P supplies. To evaluate the adaptive significance of this plasticity, the effects of unbalanced N:P supply ratio on individual lifetime fitness must be measured.

The symbionts made me do it: legumes are not hardwired for high nitrogen concentrations but incorporate more nitrogen when inoculated.

High tissue nitrogen (N) concentrations in N-fixing legumes may be driven by an evolutionary commitment to a high N strategy, by higher N availability from fixation, or by some other cause. To disentangle these hypotheses, we asked two questions: are legumes hardwired to have high N concentrations? Aside from delivering fixed N, how does inoculation affect legume N concentrations? In order to understand drivers of plant stoichiometry, we subjected four herbaceous legume species to nine levels of N fertilization in a glasshouse. Half of the individuals were inoculated with crushed nodules, whereas the other half remained uninoculated and could not fix N. Across four legume species, we found that tissue stoichiometry and nutrient content were more plastic than has been described for any other plant species. In addition, inoculated plants had higher tissue N concentrations than N fixation activity alone can explain. Rather than being hardwired for high N or phosphorus (P) demand, the legumes we examined were highly flexible in their nutrient allocation. Understanding the drivers of legume N concentrations is essential to understanding the role of N fixers in community- and ecosystem-level processes.

Effect of fertilization pulses on the production of Gracilaria birdiae seedlings under laboratory and field conditions

The genus Gracilaria is one of the most important sources of agar in the world. In Brazil, Gracilaria birdiae is the main commercially exploited species; however, overexploitation has contributed to the depletion of natural beds. In order to obtain more information so as to consolidate G. birdiae cultivation, studies under laboratory (indoor and outdoor) and field (sea and shrimp pond) conditions were conducted to evaluate the effects of fertilizer pulses on biomass and relative growth rate (RGR) of this species. The following nutrient sources used were (T1) shrimp-pond effluent, (T2) fertilizer for aquarium plants (Mbreda), and (T3) fertilizer extract of Ascophyllum nodosum (Acadian). Significant differences for growth were recorded over time for all treatments in both outdoor and field conditions (p < 0.001). The highest RGRs were recorded for treatments that used pulses of commercial fertilizers (T2 and T3) and the lowest for treatment using shrimp-pond effluent pulses (T1). The analysis of the nutrient content in tissue also showed a relationship between growth and nitrogen and phosphorus accumulation in the algal tissues. The N/P ratio indicated a significant effect on the growth of G. birdiae and the highest RGRs were registered for seedlings with a N/P ratio ≥16 (T2 and T3). In conclusion, the best results were recorded for the Mbreda and Acadian commercial fertilizers. However, although no significant differences were detected between growth and the two fertilizers (T2 and T3), the seedlings cultivated under Acadian pulses showed a better performance against environmental stress caused by reduced salinity.

Plant species differ in early seedling growth and tissue nutrient responses to arbuscular and ectomycorrhizal fungi.

Experiments with plant species that can host both arbuscular mycorrhizal fungi (AMF) and ectomycorrhizal fungi (EMF) are important to separating the roles of fungal type and plant species and understanding the influence of the types of symbioses on plant growth and nutrient acquisition. We examined the effects of mycorrhizal fungal type on the growth and tissue nutrient content of two tree species (Eucalyptus grandis and Quercus costaricensis) grown under four nutrient treatments (combinations of low versus high nitrogen (N) and phosphorus (P) with different N:P ratios) in the greenhouse. Trees were inoculated with unidentified field mixtures of AMF or EMF species cultivated on root fragments of AMF- or EMF-specific bait plants. In E. grandis, inoculation with both AMF and EMF positively affected belowground plant dry weight and negatively affected aboveground dry weight, while only inoculation with AMF increased tissue nutrient content. Conversely, Q. costaricensis dry weight and nutrient content did not differ significantly among inoculation treatments, potentially due to its dependence on cotyledon reserves for growth. Mineral nutrition of both tree species differed with the ratio of N to P applied while growth did not. Our results demonstrate that both tree species' characteristics and the soil nutrient environment can affect how AMF and EMF interact with their host plants. This research highlights the importance of mycorrhizal fungal-tree-soil interactions during early seedling growth and suggests that differences between AMF and EMF associations may be crucial to understanding forest ecosystem functioning.

Surveying Changes in Sectional Tissue Nutrient Concentrations of Hibiscus acetosella ‘Panama Red’ during Adventitious Root Formation

A study was conducted to observe changes in mineral element concentrations within different sections of leafy stem cuttings of Hibiscus acetosella ‘Panama Red’ (PP20121) during a 21-day propagation period under standard industry propagation conditions. Concentrations of 13 mineral elements were analyzed in leaves, lower stems (below substrate), upper stems (above substrate), and roots at 3-day intervals. Before root emergence (day 0–6), P, K, Zn, Ca, and Mg concentrations decreased in the shoots (including upper stems and leaves), whereas Zn, Ca, and B concentrations decreased in the lower stems. Sulfur increase occurred in lower stems before root emergence. After rooting (day 9–21), N, P, Zn, Fe, Cu, and Ni concentrations decreased in the roots; K, S, B, and Mg concentrations increased. In the lower stems, N, P, K, S, and Zn concentrations decreased, whereas B increased. Potassium concentration decreased in the leaves; P, K, S, and Zn decreased in the upper stems. Calcium and Mg increased in leaves. This study indicates specific nutrients are important in adventitious rooting, and that it is important to analyze rooting as a function of fine-scale temporal measurements and fine-scale sectional measurements.

Plant Growth Promoting Rhizobacteria-an Efficient Tool for Agriculture Promotion

Current soil management strategies are mainly dependent on inorganic chemical-based fertilizers, which caused a serious threat to human health and environment. Plant growth-promoting rhizobacteria (PGPR) are naturally occurring soil bacteria that aggressively colonize plant roots and benefit plants by providing growth promotion. Inoculation of crop plants with certain strains of PGPR at an early stage of development improves biomass production through direct effects on root and shoots growth. The major groups of PGPR can be found along with the phyla actinobacteria, bacteroidetes, firmicutes, and proteobacteria. Inoculation of agricultural crops with PGPR may result in multiple effects on early-season plant growth, as seen in the enhancement of seedling germination, plant health, vigor, height, shoot weight, nutrient content of shoot tissues, early bloom, chlorophyll content, and increased nodulation in legumes. PGPRs are reported to influence the growth, yield, and nutrient uptake by an array of mechanisms. They help in increasing nitrogen fixation in legumes, help in promoting free-living nitrogen-fixing bacteria, increase supply of other nutrients, such as phosphorus, iron and produce plant hormones that enhance other beneficial bacteria or fungi. Now a day’s an increasing number of PGPR being commercialized for various crops. Subsequently, there has been much research interest in PGPRs. Several reviews have discussed specific aspects of growth promotion by PGPRs. Therefore, PGPRs can help to generate wealth cooperatively in local communities, reducing the need for more expensive manufactured products, such as nitrogenous fertilizers and use of PGPR in world has the potential to provide valuable insight.

Traits Driving Tolerance to Atmospheric Fluoride Pollution in Tree Crops

Increased emissions of fluoride into the atmosphere contribute to reducing the sustainability of agricultural systems worldwide. In order to improve the understanding of the factors behind such phenomenon, varieties of citrus (Citrus spp.), Valencia sweet-orange, Ponkan mandarin, and Lisbon lemon and coffee (Coffea spp.), Obata, Catuai, and Apoata, were treated with fluoride nebulization. The trees were exposed to nebulization for 60 min inside a chamber by using medium (0.04 mol L−1) and high (0.16 mol L−1) doses of fluoridic acid (HF) during three nonconsecutive days in a single week, for a total of 26 days of exposure during the experiment. Sixty days after beginning nebulization, we evaluated leaf gas exchange, (ultra)structural organization, tree growth, and fluoride and nutrient concentrations in plant tissue. Photosynthesis and leaf dry mass of citrus and coffee varieties were affected differently by fluoride toxicity, and based on the tolerance index (relative leaf dry mass of control versus leaf dry mass of trees treated with 0.16 mol L−1 HF), the order of sensitivity for the varieties of each species was as follows: for citrus, lemon > mandarin > sweet-orange; and for coffee, Apoata > Catuai > Obata. The ability of the trees to control fluoride absorption most likely explained this contrast in sensitivity among varieties because both photosynthesis and leaf growth were negatively correlated with leaf fluoride concentration. Although disorganization of the thylakoids, degeneration of vascular cells, and disruption of the middle lamella occurred in leaves of all varieties exposed to fluoride, the more severe damage was observed in those with greater sensitivity to the pollutant (i.e., lemon and Apoata coffee). Taken together, these results provided insights into the factors that explain poor performance of citrus and coffee trees under fluoride pollution and also revealed the traits driving the tolerance of these crops such a limiting condition, which included a combination of the following: (i) reduced fluoride absorption, (ii) increased photosynthesis, and (iii) improved maintenance of the ultrastructural organization of leaves.