Leaf Nutrient Concentrations Research Articles

Phyllosphere antibiotic resistome in a natural primary vegetation across a successional sequence after glacier retreat

The spread of antibiotic-resistance genes (ARGs) has posed a significant threat to human health over the past decades. Despite the fact that the phyllosphere represents a crucial pool of microorganisms, little is known about the profile and drivers of ARGs in less human interference natural habitats. In order to minimize the influence of environmental factors, here we collected leaf samples from the early-, middle- and late-successional stages across a primary vegetation successional sequence within 2 km, to investigate how the phyllosphere ARGs develop in natural habitats. Phyllosphere ARGs were determined using high-throughput quantitative PCR. Bacterial community and leaf nutrient content were also measured to assess their contribution to the phyllosphere ARGs. A total of 151 unique ARGs were identified, covering almost all recognized major antibiotic classes. We further found that there was some stochastic and a core set of the phyllosphere ARGs during the plant community succession process, due to the fluctuant phyllosphere habitat and specific selection effect of plant individuals. The ARG abundance significantly decreased due to the reduction of the phyllosphere bacterial diversity, community complexity, and leaf nutrient content during the plant community succession process. While the closer links between soil and fallen leaf resulted in a higher ARG abundance in leaf litter than in fresh leaf. In summary, our study reveals that the phyllosphere harbors a broad spectrum of ARGs in the natural environment. These phyllosphere ARGs are driven by various environmental factors, including the plant community composition, host leaf properties, and the phyllosphere microbiome.

Mediating Effect of Bio-Organic Fertilizer on the Physiological Characteristics of “Qi-Nan” Agarwood from Aquilaria sinensis (Lour.)

This study examines the impact of bio-organic fertilizers on the physiological characteristics and leaf nutrient content of “Qi-Nan” agarwood seedlings. The aim is to provide a theoretical foundation for the efficient cultivation of “Qi-Nan”. The experiment was conducted under field conditions using a Randomized complete block design. The control group received no fertilization, while the three fertilizer-treated groups received vermicompost, sheep manure, or microbial organic fertilizer. The results indicate that the application of bio-organic fertilizer significantly promoted the growth of plant height and diameter, increased the contents of soluble proteins, soluble sugar, chlorophyll, and leaf nutrients; and decreased the contents of free proline, peroxidase, malondialdehyde, and other stress indices. Redundancy analysis showed that the main factors affecting the seedlings height and diameter were free proline, chlorophyll, total nitrogen, and total potassium. Principal component analysis and membership function analysis revealed significant variations in growth, physiological characteristics, and nutrient content among the three fertilizer groups and the control group, with vermicompost > microbial organic fertilizer > sheep manure > no fertilization. In conclusion, biological organic fertilizer significantly promotes the growth of “Qi-Nan” seedlings, and vermicompost is the most effective fertilizer in this experiment.

Ionome of Lithuanian Populations of Purple Loosestrife (Lythrum salicaria) and Its Relation to Genetic Diversity and Environmental Variables

Fifteen riparian populations of Lithuanian Lythrum salicaria were assessed for leaf macronutrient, micronutrient and non-essential element concentrations and compared to the former obtained molecular data at amplified fragment length polymorphism (PLP.AFLP) loci. Inductively coupled plasma mass spectrometry was used to profile the contents of 12 elements in the leaves. The leaf nutrient concentrations were within normal ranges for growth and development and heavy metal concentrations did not reach toxic levels. The concentrations of macroelements such as nitrogen, potassium, calcium and magnesium were in the range of 23,790–38,183; 7327–11,732; 7018–12,306; and 1377–3183 µg/g dry mass (d. m.), respectively; the concentrations of micronutrients such as sodium, iron, zinc and copper varied in the ranges of 536–6328; 24.7–167.1; 10.88–26.24; and 3.72–5.30 µg/g d. m., respectively, and the concentrations of non-essential elements such as lead, nickel, chromium, and cadmium were in the intervals of 0.136–0.940; 0.353–0.783; 0.207–0.467; and 0.012–0.028 µg/g d. m., respectively. When comparing the maximum and minimum values for site elements of L. salicaria, the concentration of N varied by 1.6, K—1.6, Ca—1.8, Mg—2.3, Na—6.1, Fe—6.8, Zn—2.4, Cu—1.5, Pb—6.9, Ni—2.2, Cr—2.2, and Cd—2.3 times. The coefficient of variation (CV) of element concentrations in sites was moderate to large: N—15.4%, K—14.3%, Ca—18.6%, Mg—24.8%, Na—50.7%, Fe—47.0%, Zn—24.9%, Cu—14.5%, Pb—57.1%, Ni—30.11%, Cr—26.0%, and Cd—38.6%. Lythrum salicaria populations growing near regulated riverbeds were characterized by significantly (p < 0.05) lower concentrations of Ca and Mg, and significantly (p < 0.05) higher concentrations of N, K, Fe, Na, Ni, Cr and Cd. The PLP.AFLP was negatively correlated with concentrations of N, Na, Fe, Ni, Cr, and Cd. The L. salicaria population with the lowest leaf N and Na concentration showed the highest genetic polymorphism (PLP.AFLP = 65.4%), while the least polymorphic population (PLP.AFLP = 35.0%) did not show extreme concentrations of either element. In conclusion, our elemental analysis of L. salicaria populations showed that ionomic parameters are related to genomic parameters, and some habitat differences are reflected in the ionomes of the populations.

Grafting improves the growth and yield of Cucumis sativus plants grown under salinity stresses by modulating antioxidant enzymes, water status and nutrient uptake

The purpose of this research was to determine if salt-tolerant rootstock could be used to increase cucumber yield and quality in saline environments. Greenhouse experiments were conducted for 2020 and 2021, with five salt stress-tolerant rootstocks (Super Green (squash hybrid, Modesto seeds company, Modesto, California 95357, U.S.A.), Just (squash hybrid, American Takii seeds, California, U.S.A.), bottle gourd 1 (Legenaria siceraria, PI 491352), bottle gourd 2 (Legenaria siceraria, PI 491365), watermelon (Citrullus lanatus var. Colocynthoides), and Laurens (cucumber cultivar, Enza Zaden, Enkhuizen, Netherlands) and salt-sensitive genotypes of Luerans (scion). Specimens of these genotypes were subjected to distinct salinity levels of 0, 50, 100, and 150 mM (NaCl). The morphophysiological responses of these genotypes to salt stress were evaluated. Under normal and stressful conditions, the plant height, leaf area (LA), leaf water content (LWC), number of leaves, root dry matter, shoot dry matter, rates of leaf appearance and stem elongation, fruit yield, and quality increased significantly in grafted cucumber plants compared with non-grafted individuals (control). Similar findings were noted in the physiological properties of antioxidant enzymes, proline content, and leaf nutrient concentration (N, P, K, Ca, Mg, Fe, Zn, and Na). Grafting of Luerans on five rootstocks significantly elevated the antioxidant enzymes (catalase and peroxidase) activity level, increased proline accumulation, and reduced leaf sodium (Na) content.

Densidade de plantas e morfologia foliar afetam a produtividade, qualidade e nutrição do algodoeiro

ABSTRACT In sandy soils with frequent drought events, the choice of cultivar and plant density is crucial to improve water use efficiency and avoid losses in cotton yield and fiber quality. This study aimed to evaluate cotton cultivars’ yield and fiber quality at different plant densities. The study was carried out during two growing seasons (2017/2018 and 2018/2019) on sandy soil in southeastern Brazil. The cultivar TMG 47B2RF showed 27 and 29% higher yields under low and medium plant density, respectively, when compared with the highest plant density. The higher yield was due to the higher number of bolls in relation to the cultivar DBB 509B2RF. The boll weight of cultivar DBB 509B2RF was 23 and 22% higher under low and medium plant density, respectively. Fiber length and strength were higher in TMG 47B2RF compared to DBB 509B2RF. The leaf nutrient content was higher in DBB 509B2RF, except for Ca and Mg. When there is a regular rainfall, the low plant density results in higher yields, but intermediate plant density is the best option in cropping seasons with severe drought. The high density of plants in sandy soil environments was never a better option for none of the cultivars.

Effect of Nitrogen and Phosphorus on Flowering, Bulb Yield and Nutrient Contents in Leaves of Tuberose (Polianthes Tuberose L.) cv. Prajwal

Effect of Nitrogen and Phosphorus on Flowering, Bulb Yield and Nutrient Contents in Leaves of Tuberose (Polianthes Tuberose L.) cv. Prajwal

Nanoparticulate Fertilizers Increase Nutrient Absorption Efficiency and Agro-Physiological Properties of Lettuce Plant

The extensive use of chemical fertilizers is responsible for numerous environmental problems including low food quality, soil degradation, and toxicity to beneficial living organisms in the soil. Nano-fertilizers (NFs) application may be a promising solution for combat these challenges. The current study focused on the efficiency of applying small amounts of NFs incorporated with conventional nitrogen, phosphorus, and potassium (NPK) fertilizers to reduce the quantities of conventional fertilizers (CFs) in lettuce cultivated in sandy soil. This study evaluated the effect of these incorporations on plant growth, yield, phytochemical accumulation, leaf nutrient, and leaf nitrate. A pot experiment was conducted during the winter seasons of 2020/2021 and 2021/2022 using the following treatments: CF100: 100% CFs, CF75NF25: 75% CFs + 25% NFs, CF50NF50: 50% CFs + 50% NFs, CF25NF75: 25% CFs + 75% NFs, and NF100: 100% NFs (=10% of CFs). Our findings displayed that the CF75NF25 and CF50NF50 treatments recorded the highest plant growth parameter values (plant length, root length, number of leaves, and fresh and dry biomass). The maximum of chlorophyll fluorescence measurements (photosystem II efficiency) were obtained in plants fertilized with CF75NF25, followed by CF50NF50 and CF100. The improvement ratios of photosynthetic pigments (Chlorophyll (Chl) a, b, and total) for CF75NF25 were 23.77, 50, and 23.72% in the first season and 10.10, 51.0, and 24.90% in the second season for Chl a, b, and total, respectively, as compared with the CF100 treatment. A similar tendency was observed for the CF50NF50 treatment. Generally, CF75NF25 significantly raised the content of total phenolic compounds (TPC), total flavonoid content (TFC), and antioxidant activity (AOA) in lettuce plants by 36.09, 47.82, and 40.16% in the first season and by 30.39, 37.53, and 32.43% in the second season, respectively, compared with CF100. In addition, the levels of leaf nutrient content and uptake of N, P, and K were significantly higher in plants fertilized with CF75NF25 compared to the other treatments, whereas CF25NF75 had the lowest values among the different treatments across both seasons for most of the tested traits. The nitrate content in lettuce leaves (NO3−) for both seasons was lower than the acceptable level for human consumption. These results indicate that incorporating a low concentration of NFs into CFs could be a promising strategy to reduce the amount of CFs to 75% or 50% of lettuce NPK requirements without significant adverse effects on the growth and productivity of lettuce plants cultivated in sandy soil.

The Dynamics of Immature Rubber Photosynthetic Capacities Under Macronutrients Deficiencies

Pará rubber produces natural latex which is essential for the industries. Rubber plant in immature phase is prone to macronutrient deficiencies due to improper management practices in the field and the nature of immature plants that have sensitive physiological responses under stress conditions. The study aimed to assess the effect of macronutrient limitation on immature rubber trees’ photosynthetic capacity and growth. The immature rubber was pot-grown inside the greenhouse with a completely randomized design experiment and nutrient limitations used as the treatments. The treatments consisted of 5 levels, namely, NPK; NP (-K); NK (-P); PK (-N); Control (-NPK). Photosynthetic capacity parameters (Vc max: maximum rate RuBisCO carboxylation, Jmax: RuBP regeneration rate, and TPU: Triose Phosphate Utilization), tree growth (plant height, flush number, leaf number, stem diameter), and leaf macronutrient (N, P, and K) concentrations were periodically measured. Welsch’s test (α = 0.05) continued with Games-Howell pairwise comparison, followed by Pearson’s correlation test and polynomial regressions were performed to describe the nutrient limitation and photosynthetic capacity relationships. Results showed that the leaf nutrient concentration corresponds with the given treatments, even though it was above the critical level for immature rubber. The limitation of N fertilization slightly reduced plant development and growth such as height, leaf number, flush number, relative growth rate, and photosynthetic capacities. However, the P and K limitation effect could not be observed clearly in the observation periods on growth and photosynthetic capacity parameters. Furthermore, the mobility rate of nutrients from the soil to the plants and its translocation inside plant organs played more essential role in plant growth and photosynthetic capacities. Prolonged observation periods on various rubber clones have to be performed to deeply understand the effects of nutrient deficiencies on immature rubber tree morphophysiological activities. HIGHLIGHTS Rubber plant in immature phase have sensitive physiological responses under stress conditions, and it is prone to macronutrient deficiencies due to improper management practices in the field Assessment of macronutrient limitation effect on immature rubber trees’ photosynthetic capacity and growth is essential to understand how the plants strive under the nutrient scarcity and providing a perspective which nutrient is more essential The N fertilization played more essential role compared to P and K, for immature rubber growth and photosynthetic activity GRAPHICAL ABSTRACT

Establishing Critical Leaf Nutrient Concentrations and Identification of Yield Limiting Nutrients for Precise Nutrient Prescriptions of Oil Palm (Elaeis guineensis Jacq) Plantations

African oil palm (Elaeis guineensis Jacq.) is a bulk feeder of nutrients. In this study, we aimed at devising strategies for efficient nutrient management in the oil palm plantations of the Krishna River basin located in Andhra Pradesh, India by assessing soil fertility status, establishing optimal leaf nutrient concentrations and identifying yield restrictive nutrients. In total, 67 oil palm plantations were surveyed from this area in 2020, soil samples were collected and analysed for different soil properties, including pH, EC, SOC, available P, K, S, exchangeable Ca and Mg, and hot water-soluble boron (HWB) in surface (from 0–20 cm depth), subsurface (from 20–40 cm depth) and deep (from 40–60 cm depth) soil layers. As per DRIS (Diagnosis and Recommendation Integrated System) indices estimated in this study, the order of requirement of nutrients is Nitrogen (N) > B > K > P > Mg for this area. Optimum leaf nutrient concentrations ranged between 2.07–4.29%, 0.13–0.27%, 0.52–0.94%, 0.44–0.76% and 44.97–102.70 mg/kg for N, P, K, Mg and B, respectively. In surveyed plantations, about 15, 6, 16, 9 and 12 percent of leaf samples had less than optimum concentration of N, P, K, Mg and B respectively. Nitrogen and Boron are the major yield limiting factors in this region. Leaf nutrient concentrations need to be maintained at the optimum ranges as estimated above for higher productivity in the Krishna basin area.

Methyl jasmonate and type of fertilization affect growth, production and accumulation of sulforaphane in black radish taproot

ABSTRACT Arable areas frequently lack sufficient soil nutrients, necessitating use of fertilizers, whose excessive usage presents a threat to the environment, human health, and food safety. Natural plant-based growth regulators are inexpensive and favorable to the environment. Phytohormone methyl jasmonate (MeJA) is important in improving quality, productivity, and resistance against various pests, diseases, and environmental challenges. The objectives of this study were to compare effects of fertilization and application of MeJA on taproot yield, leaf nutritive value, and accumulation of sulforaphane (SF) in black radish (Raphanus sativus L. var. niger) taproots. Sulforaphane is a potent cytoprotective agent, promoting antioxidant, anti-inflammatory, antiglycative, and antimicrobial effects. The treatments (T) were: T1 = 3 t∙ha−1 of poultry litter (PL); T2 = PL+2.5 ml∙L−1 foliar application of micro-sulfur (S); T3 = PL+S+3 g∙L−1foliar application of sorbitol (SO); T4 = 480 kg∙ha−1 of NPK 20,20,20; T5 = NPK+S; T6 = NPK+S+SO. The second experiment was foliar application of MeJA at 0, 50, or 100 mg∙L−1. Application of treatments and MeJA alone, and in combination, improved growth, leaf nutrient concentrations, taproot yield components, and accumulation of SF in black radish. The T3 treatment produced the highest relative chlorophyll content (SPAD index = 31.56), most leaf area (495.33 dm2), tallest plants and longest taproot (57.95 and 17.68 cm), highest dry matter of leaf and taproot (8.10 and 12.57%), heaviest fresh weight of leaves and taproots (249.15 and 360.40 g) and highest total taproot yield (120.13 t∙ha−1). Treatment T6 produced highest nitrogen (N), phosphorus (P) and potassium (K) content in leaves, 3.57, 0.52 and 3.87 g 100 g, respectively, and highest SF content in taproots (8.5 mg/100 g). The 100 mg∙L−1 MeJA rate produced the largest leaf area (480.10 dm2), highest dry matter of leaf and taproot (7.31 and 11.65%), heaviest fresh weight of taproot (356.23 g), highest N, P, K and S content in leaves (3.45, 0.47, 3.69 and 0.375 g/100 g), most taproot yield (118.74 t∙ha−1) and highest FS content in taproot (9.62 g/100 g). The 100 mg∙L−1 foliar application of MeJA was effective in increasing and improving vegetative growth, taproot productivity, and FS accumulation in black radish.

Elevational variation in soil phosphorus pools and controlling factors in alpine areas of Southwest China

As an important life element in the Earth’s ecosystem, soil phosphorus (P) is of great significance to stability and sustainable development of terrestrial ecosystems. However, seasonal variations in different soil P pools and their regulatory mechanisms along elevations are not fully understood. Here, we investigated seasonal variations in soil P pools including total P (TP), available P (AP), inorganic P (IP), organic P (OP), labile P, moderately labile P, and stable P in topsoil (0–15 cm) along different elevations (2600–3900 m) in the Yulong Snow Mountain. The associated drivers including leaf nutrient contents, soil properties, micro-climate, and microbial parameters were also examined. We found that all soil P fractions reached a maximum at mid-elevations (2,900 m and 3,200 m), possibly due to the more active microorganisms and suitable soil climatic conditions for advancing P weathering. Meanwhile, soil AP pool was also observed to be tightly related to the leaf P content along elevations. Unexpectedly, most soil P pools did not show seasonal changes, except for AP showing significantly higher level in the wet season than in the dry season, owing to the high temperature and microbial activity for promoting P release in the wet season. Consequently, we found that microbial P, acid phosphatase and dissolved organic carbon had a stronger influence on different P pools than other soil factors. Moreover, there was a strong interaction of labile P and moderately labile P with soil environments (i.e. soil moisture, temperature, dissolved organic carbon). Collectively, our results revealed the elevational shifts in soil P pools and potential mechanisms in Yulong Mountain, and provided an important theoretical basis for soil P dynamics in response to environments in mountain ecosystems.

The fruit peel anatomy, leaf nutrient content, and fruit quality of ‘Terigas’ mandarin in relation to fruit cracking

‘Terigas’ mandarin is one of the cultivars cultivated in almost all of Indonesia’s provinces. However, this cultivar is prone to cracking, and little research has been conducted on fruit cracking in Indonesia. The goal of this study was to determine the effect of fruit cracking on peel anatomy, leaf nutrient content, and fruit quality in ‘Terigas’ cultivar. A Completely Block Design (CBD) with three replications was used. Results showed that the peel thickness of uncracked with big fruit size was significantly the highest, while epidermis of cracked fruit with big size was the thickest. The largest oil glands size was shown in uncracked fruit with a big size. The leaf that supported uncracked fruit with a big size had the highest Ca content, whereas the lowest Ca content was observed in the leaf that supported cracked fruit with a small size. In contrast, the leaf that supported cracked with a small fruit size had the highest Zn content. Regardless of fruit size, fruit weight, fruit diameter, and pH of uncracked fruit were significantly much higher than cracked ones. Nevertheless, the Total Soluble Acid and vitamin C of cracked fruit were significantly higher than uncracked ones. This study may provide the important keys to the fruit cracking effect, and as a tool to lessen citrus fruit cracking, especially in ‘Terigas’ mandari

Intensity Of Soil Treatment And Frequency Of Inorganic Fertilizer Application On Nutrient Levels And Growth Of Palm Oil (Elaeis guineensis Jacq) At The Replanting Stage

Oil palm is a plantation crop that produces vegetable oil, and people highly need it, so it requires efforts to increase its production. One way is by utilizing existing land without having to open new oil palm plantation areas with replanting. This study aimed to analyze the effect of fertilization frequency on different tillage and to get the best fertilization frequency on different tillage on leaf nutrient levels and growth of oil palm plants. This research experimented with a split-plot design (SPD) with a randomized block basic design. The factors tested in this study consisted of the main plot, e.g., tillage (No tillage, 1 time of tillage, 2 times of tillage) and subplots, e.g., the fertilization frequency (D1: 5 times frequency of NPK fertilization D2: 4 times frequency of NPK fertilization D3 : 3 times frequency of NPK fertilization). The two factors were combined, and 12 treatment combinations were obtained. Each treatment combination consisted of 3 groups, totaling 36 experimental units. Each experimental unit consisted of 2 plants, so 72 plants were obtained. The data obtained were analyzed using variance and further tested with the honest significant difference test (BNJ) at the 5% level and advanced test analysis using the Satker application (SAS). This study showed that NPK fertilization with a frequency of 2 times in 2 times tillage increased vegetative plant growth (increased stem circumference). The main plot of tillage two times increased leaf nutrient content (leaf N content) and plant vegetative (plant height gain and stem circumference increase). NPK fertilization with a frequency of 2 times increased plant growth (increased stem circumference).

Large Chestnut Trees Did Not Respond to Annual Fertiliser Applications, Requiring a Long-Term Approach to Establishing Effective Fertilisation Plans

Due to the high value of the fruit, the European chestnut (Castanea sativa Mill.), usually grown in agroforestry systems, has been planted as a single species in orchards managed with increasingly intensive cropping practices, such as the regular use of fertilisers. This justifies research into establishing fertilisation programmes oriented towards ecological intensification. In this study, the results of fruit production, plant nutritional status and soil properties are reported from a field trial in which three NPK fertilisers (20:7:10, 13:11:21 and 7:14:14) and a control treatment were used. Chestnut yields did not vary significantly between treatments, although the mean values of the control showed a clear downward trend. N supplied by the fertilisers seems to have been the most important factor in the difference between the fertilised and control treatments, since leaf N concentrations were lower in the control and often below the lower limit of the sufficiency range. Soil inorganic N levels in the autumn, and tissue N concentrations of the herbaceous vegetation developing beneath the trees, indicated risks of N loss to the environment and highlighted the importance of this vegetation remaining during the winter. The chestnuts’ poor response to fertiliser applications was attributed to the buffering effect of the large perennial structure of the trees on the distribution of nutrients to the growing plant parts. In large trees, it seems appropriate to base the annual fertilisation plan on leaf nutrient concentration. Thus, farmers probably should avoid spending money on fertilizer applications as long as leaf nutrient concentrations do not approach the lower limits of sufficiency ranges.

Influence of fertigation and foliar sprays on yield, nutrient content of leaf, fruit and soil and economics of cultivation of papaya variety Surya

Influence of fertigation and foliar sprays on yield, nutrient content of leaf, fruit and soil and economics of cultivation of papaya variety Surya

Soil physicochemical characteristics and leaf nutrient contents on banana farms of North Queensland, Australia

Context Banana production in Australia is in three primary sub-regions within tropical North Queensland and the industry faces a variety of challenges including costs of production, disease and pests, and environmental impacts. The range of soil characteristics and banana leaf nutrient status on banana farms has not previously been systematically described. This knowledge gap makes it difficult to adapt research, management recommendations, and regulations to the needs of the three primary growing sub-regions. Aims In this work, we aimed to identify key soil factors that differentiate growing sub-regions, and provide context for future research and industry regulation. Methods We characterised soil and banana leaf samples from 28 banana farms on soil types accounting for >85% of Australia’s banana production. Key results and conclusions Variation in soil properties and leaf nutrient concentrations were driven largely by site- (principal component 1 in both cases) and management-related variables (principal component 2 in both cases). Management-related foliar nutrient concentrations did not differ between regions despite differences in the associated soil variables. The most important site characteristics appeared to be soil parent material and climate. The Mareeba sub-region has basaltic soils, low rainfall and temperature, whereas the other two sub-regions are hotter, wetter and have a variety of soil parent materials. Leaf nitrogen concentrations were mostly below the regulated limit for additional nitrogen fertiliser application. Implications Our findings can facilitate sub-region-specific site selection for research, extension, and monitoring and more targeted regulation of banana production- and environment-related issues.

Predicting ecosystem productivity based on plant community traits.

With the rapid accumulation of plant trait data, major opportunities have arisen for the integration of these data into predicting ecosystem primary productivity across a range of spatial extents. Traditionally, traits have been used to explain physiological productivity at cell, organ, or plant scales, but scaling up to the ecosystem scale has remained challenging. Here, we show the need to combine measures of community-level traits and environmental factors to predict ecosystem productivity at landscape or biogeographic scales. We show how theory can extend the production ecology equation to enormous potential for integrating traits into ecological models that estimate productivity-related ecosystem functions across ecological scales and to anticipate the response of terrestrial ecosystems to global change.

Effect of humic substances on yield and nutrient contents of Eggplant Santana (Solanum melongena) plants in gray-brown soil

Humic substances promote the conversion of nutrients into forms available to plants. It also stimulates seed germination and viability, and its main effect usually being more prominent in the roots. This study was conducted in a randomized complete block design with three replications in Gobustan, Azerbaijan, in 2021 growing season, to determine the effects of different doses (0, 250, 500 and 1000 ppm) of humic substances such as humic acid (HA), fulvic acid (FA) and humic fulvic acid (HFA) on fresh yield and nutrient contents (N, P and K) of Eggplant Santana (Solanum melongena var. esculentum Santana) plants in a field experiment. According to the results of this study, humic substance treatments increased the fresh yields and leaf nutrient contents of Eggplant Santana, and this increase was found to be significant. The highest value for highest fresh yields and leaf NPK contents of Eggplant Santana plants were obtained from 1000 ppm HFA dose. These results suggest that 1000 ppm HA and FA combination to the standard humic substances application will be sufficient to obtain adequate fresh yield and nutrient contents in Eggplant Santana leafs.

Prediction of pilocarpine production from soil attributes and the nutritional status of Pilocarpus microphyllus

Jaborandi (Pilocarpus microphyllus), an endemic species of the Brazilian flora threatened with extinction, is the only natural source of pilocarpine, an alkaloid widely used in the pharmaceutical industry. This compound is extracted from the leaf tissue and may be affected by edaphic and nutritional variations. The aim of this study was to correlate soil chemical parameters and leaf nutrient contents with pilocarpine production in Pilocarpus microphyllus plants collected from areas of the Carajás National Forest. In samples collected from 83 plants, pilocarpine, leaf nutrients (N, P, K, S, Mg, Ca, B, Zn, Cu, Fe, and Mn), and soil chemical attributes (P, K, S, Mg, Ca, B, Zn, Cu, Fe, Mn, organic matter, pH, and Al) were evaluated. The mean values of pilocarpine varied between 0.4% and 2.2% of the leaf dry matter, which are rare. In general, the soils presented low nutrient availability, marked acidity, and very high Fe and Mn values. In the leaves, low concentrations of N, P, and K and high leaf concentrations of Fe (2239.13 mg kg−1) and Mn (2095.46 mg kg−1) were observed, which suggested that P. microphyllus is a metal accumulator species. Through multivariate analysis, the model that best predicted pilocarpine production was composed of leaf N, leaf Mg, soil Fe (positive predictors), soil S, and leaf P (negative predictors). The nutritional management for large-scale cultivation of P. microphyllus should be focused mainly on the amounts of N, Fe, and Mg.

Polysaccharides combined to copper and magnesium improve tomato growth, yield, anti-oxidant and plant defense enzymes

The search for sustainable technologies to increase yield are fundamental for a modern agriculture. Polymers of biological origin (e.g., polysaccharides) have been studied for their potential use in agriculture. These substances present a great possibility of agricultural uses allowing their combination with nutrients to improve the uptake by plants. In this regard, the association of copper and magnesium to polysaccharides was investigated in the tomato cultivation in pots conducted with fertigation under protected environment. Two experiments were conducted: (i) foliar application of polysaccharides and their association with copper and magnesium in the initial growth of tomato plants; and (ii) tomato yield with foliar application of polysaccharides and their association with copper and magnesium. Growth, leaf nutrient content, enzymes and biochemical variables, fruit yield and leaf disease severity index were analyzed. The foliar sprays with polysaccharides in the combination with copper and magnesium was efficient to promote plant growth and yield. It also improved the concentration of antioxidant enzymes and the β,1,3 glucanase enzyme, while reducing the severity of powdery mildew in tomato leaves.