Green Leaf Research Articles

Investigating the Effect of Hydrafiber and Biochar as a Substitute for Peat-Based Substrate for Zinnia (Zinnia elegans) and Snapdragon (Antirrhinum majus) Production

Increasing environmental and economic concerns necessitate the research for peat moss alternatives, aiming to balance ecological sustainability with cost-effectiveness. This study assessed whether biochar (BC) and hydrafiber (HF) could be a partial replacement for peat moss as substrate components. Twelve substrates were formulated by either mixing BC (20%, 40%, and 60%, by vol.) with HF (20%, 40%, and 60%, by vol.), with the remaining being peat moss or mixing BC (0%, 20%, 40%, and 60%, by vol.) with the commercial substrates (CS) to grow zinnia (Zinnia elegans) and snapdragon (Antirrhinum majus) plants in containers. The physical properties of the substrates, including container capacity, total porosity, air space, bulk density, and chemical properties including leachate pH and electrical conductivity (EC) were measured. Plant growth parameters including growth index (GI) and leaf greenness (indicated with SPAD), biomass, and number of flowers were measured biweekly. The results showed all the substrate mixes had similar air space, bulk density, and SPAD. Treatment with 20% BC and 80% CS yielded the highest GI, biomass, and numbers of flowers in both zinnia and snapdragon. In conclusion, BC could be used to partially (20%) replace commercial substrate mix for container-grown zinnia and snapdragon.

Green tea supplementation prevented oxidative stress, fibrosis, and myocardial damage in isoproterenol-induced Swiss albino mice

IntroductionOne of the main causes of death and morbidity in people with cardiovascular disorders is myocardial infarction. This study investigated the impact of green tea (GT) leaf powder on isoproterenol (ISO)-induced myocardial infarction in Swiss albino mice. Methods and materials4 to 5 weeks male Swiss albino mice were divided into four groups with 6 mice in every group: Control, ISO, Control + GT and ISO+ GT leaves powder. All of the mice were sacrificed at the end of the investigation. Heart organ and blood plasma samples were taken, and they were tested for oxidative stress indicators and several biochemical parameters. To investigate the formation of mononuclear cells and fibrosis in the heart histopathological staining of tissue sections was also carried out. ResultsIn this experiment, supplementation with green tea leaf powder in ISO-administered mice prevented the increased activity of the AST, ALT, and ALP enzymes. Additionally, three more tests were performed such as CK-MB, Creatinine, and Uric acid whose levels were increased by isoproterenol, and treatment of green tea reduced these elevated levels. Due to the supplementation of green tea leaf powder, ISO-administered mice had lower levels of lipid peroxidation product, nitric oxide, advanced protein oxidation product, and myeloperoxidase. Mice exposed to ISO had considerably higher levels of oxidative stress markers and lower levels of cellular antioxidants including catalase activity, SOD activity, and reduced glutathione concentration. Additionally, the heart of ISO-induced mice revealed substantial fibrosis and inflammatory cell infiltration. Furthermore, green tea leaf powder supplementation prevented inflammatory cell infiltration and fibrosis in ISO-administered mice. ConclusionIn conclusion, the findings imply that supplementing with green tea leaf powder might lower the risk of myocardial infarction in mice given ISO, potentially by reducing oxidative stress, inflammation, and fibrosis.

Far-red radiation management for lettuce growth: Physiological and morphological features leading to energy optimization in vertical farming

Recently, far-red wavelengths (FR, 700–750 nm) have been largely investigated in indoor cultivation systems due to their morphological effects on plants (e.g., leaf expansion and stem elongation), resulting also in increasing yield. This work investigated the effect of substituting part of the red (R) and blue (B) radiation with far-red radiation, while keeping constant the photon flux density, in the light spectrum for lettuce grown in a vertical farm. Lettuce (Lactuca sativa var. Canasta) plants were transplanted and grown in an ebb-and-flow system for 29 days. During the cycle, plants were subjected to five different light treatments: a control treatment consisting of an optimized R and B spectrum (ratio of 3; RB3) with a photosynthetic photon flux density of 200 µmol m−2 s−1, and four treatments in which R and B were partially replaced by 10, 30, 50 and 70 µmol m−2 s−1 of FR light, resulting in an increasing FR fraction. Biomass production and most of the morphological parameters were affected from 15 days after transplanting (DAT), while stomatal conductance from 22 DAT. Leaf greenness and specific leaf area values were influenced by the FR radiation starting from 8 DAT. At 29 DAT, substitution of an amount of R and B photons equal to 30 (RB3–30) or 50 (RB3–50) µmol m−2 s−1 with the same amount of FR radiation resulted in increased leaf biomass in both fresh (+49 and +47%, respectively) and dry weight (+45 and +42%, respectively). With RB3–30, the increase was due to leaf area expansion (+103%), whereas stomatal conductance (gs) and quantum efficiency of photosystem II (ΦPSII) did not change compared with the spectrum with only R and B. With RB3–50, gs and ΦPSII decreased compared with RB3 (-27 and -6%, respectively), but the greater biomass accumulation was supported by the greater leaf expansion (+119 %). The adoption of RB3–30 and RB3–50 also promoted light use efficiency (+45 and +42 %, respectively), lighting energy use efficiency (+48 and +53 %, respectively) and therefore the overall energy performance of the system. The adoption of RB3–30 and RB3–50 is a valid strategy to increase yield for lettuce production, but further studies, also in relation to blue radiation intensity, are needed to avoid the negative effect on leaf pigmentation.

Biosynthesis of silver nanoparticles using green tea leaf extract and their structural and optical analysis

In the present study, silver nanoparticles (Ag NPs) were synthesized by biosynthesis method using Green tea leaf extract. Biosynthesis is an easy, economical, and environmentally friendly method to prepare NPs. The synthesized NPs were characterized by using an X-ray diffraction spectrum (XRD), UV-Vis spectra, Tauc plot and Dynamic light scattering spectrum analysis. The XRD results of biosynthesized Ag NPs show that the particles are crystalline and face-cantered cubical in shape, with an average size of 14 nm. UV-visible spectra studies and Tauc plot analysis confirm the excellent optical properties of the Ag NPs. Due to these outstanding qualities, we anticipated that the use of green-produced Ag NPs would result in an exponential increase in various applications. Ag NPs exhibit cytotoxicity and anticancer characteristics, antibacterial, antioxidant, and antifungal activity.

OsRCI-1-Mediated GLVs Enhance Rice Resistance to Brown Planthoppers.

Green leaf volatiles (GLVs) play pivotal roles in plant anti-herbivore defense. This study investigated whether the rice 13-lipoxygense gene OsRCI-1 is involved in GLV production and plant defense in rice. The overexpression of OsRCI-1 (oeRCI lines) in rice resulted in increased wound-induced levels of two prominent GLVs, cis-3-hexen-1-ol and cis-3-hexenal. In a previous study, we found that the overexpression of OsRCI-1 reduced the colonization by the rice brown planthopper (BPH, Nilaparvata lugens) but increased the attractiveness to the egg parasitoid Anagrus nilaparvatae compared to wild-type (WT) plants. This study found that when cis-3-hexen-1-ol, but not cis-3-hexenal, was added to WT plants, it could change the BPH's colonization preference, i.e., more BPHs preferred to colonize the oeRCI lines. The exogenous application of cis-3-hexen-1-ol or cis-3-hexenal to BPH-infested WT plants could weaken or overturn the preference of A. nilaparvatae for oeRCI lines. However, field experiments revealed that only cis-3-hexenal was attractive to the parasitoid and increased the parasitism rates of BPH eggs. These results indicate that OsRCI-1 is involved in rice GLV production and therefore modulates both direct and indirect defense in rice.

A leaf-mimic material based on polyurethane microcapsules and Cr2O3 for hyperspectral stealth

Targets can achieve invisibility in the vegetation environments by simulating the reflection spectra of plant green leaves. However, balancing the accuracy and stability of simulation effects, particularly in simulating spectral features caused by water in the leaves, is often challenging. Herein, polyurethane microcapsules encapsulating liquid water (W-PUMCs) were prepared by inverse emulsion polymerization, then mixed with Cr2O3 in specific proportions into the epoxy resin matrix to obtain a material capable of simulating the reflection spectra of green leaves in the visible and near-infrared bands. The normalized similarity (NS) between the spectrum of this material and that of plant (cherry) green leaf can reach 0.9779 in the range of 400–2500 nm. W-PUMCs are used to simulate the spectral characteristics caused by water in the leaves because the spectral NS between W-PUMCs and the green leaf in the 1100–2200 nm range is 0.9930. Cr2O3 is employed to simulate the other major spectral features of green leaves. This strategy guarantees simulation accuracy while simplifying the preparation process and reducing production costs and providing solutions to spectral simulation in the fields of military stealth and ecological protection.

Propagule origin and soil organic carbon content determine the growth and yield of Amorphophallus muelleri Blume

Amorphophallus muelleri Blume locally called Iles-iles or porang becomes a new commercial commodity in Indonesia. The tuber as the most economic value contains high glucomannan. It has been speculated that the high variation in production among farmers is due to different planting materials and soil organic carbon (SOC). Thus, the research aimed to evaluate the growth and yield of A. muelleri from different planting materials and levels of SOC. The research was carried out at Leuwikopo Experimental Station IPB Bogor from December 2021 to August 2022, using a nested design. The main plot was the level of SOC (2%, 3%, 4%, 6%), and the sub-plot was planting materials (seeds, bulbils, and tubers from leaf cuttings). The results showed SOC status determined growth and yield. Plant height, stem diameter, number of leaves, canopy width, leaf greenness, number of tubers, weight, and size of tubers, stomatal conductance, and intercellular CO2 were significantly affected by SOC level. SOC at a level of 6% stimulated the highest growth and yield. Planting materials also determined the growth and yield. Plants originating from bulbils produced the highest yields, followed by tuber from leaf cuttings, and seeds. It is recommended to plant bulbils accompanied by maintaining SOC at a level of 6%.

Yield and Fruit Characteristics of Tomato Crops Grown with Mineral Macronutrients: Impact of Organo-Mineral Fertilizers through Foliar or Soil Applications.

The utilization of plant biostimulants has gained importance as a strategy by which to improve plant productivity and soil health. Two independent trials were conducted across two seasons (2021 and 2023) to evaluate the effects of foliar or soil applications of various commercial organo-mineral fertilizers (Futuroot®, Radicon® Amifort®) with biostimulant action that is exerted on yield and fruit characteristics of processing tomato crops (cv Taylor F1) that have been exposed to mineral macronutrients. These treatments were administered three times during the season: at the transplanting, pre-flowering and berry development stages. In the first trial, conducted in two fields characterized respectively by low and high fertility, foliar applications of Radicon®, which is based on humic acid and amino acids, increased the leaf greenness index SPAD compared with the control. Furthermore, the leaf green colour intensity (SPAD index), measured during the reproductive phases of the tomato exhibited a positive correlation (R2 = 0.726) with the marketable yield obtained. This increase in marketable yield was significant in the biostimulant treatment compared with the control in both soils, especially in the soil characterized by lower fertility (16.1%), when compared with the more fertile soil (6.8%). In the second trial, conducted in the low-fertility field mentioned above, soil applications of all biostimulants (Futuroot®, Radicon® and the combinations [Radicon® + Amifort-Plus®]) significantly increased the marketable yield by 27.8%, 13.5% and 27.7%, respectively, compared with the control. The most significant beneficial effects of both Futuroot® and [Radicon® + Amifort®] could be attributed to the combination of humic acids and auxins, cytokinins or microelements (Zn, Mn, MgO) present in the formulation of these products. Furthermore, the increase in marketable yield obtained when Radicon® was applied to leaves was higher (16.1%) than that observed with soil application (13.5%). In both trials, no relevant effects of biostimulant products were observed on most of the physicochemical characteristics of tomato fruits. In conclusion, the biostimulants based on humic acid and amino acids combined with chemical fertilizers tested in the present study and applied by fertigation were more effective in improving tomato yield, and therefore they can be recommended for efficient agricultural production.

Root inoculation with beneficial soil microbes enhances indirect plant defences induced by insect feeding and egg deposition

Abstract Plants can respond to insect egg deposition by emitting oviposition‐induced plant volatiles (OIPVs) recruiting parasitoids. The recruitment of carnivore insects in response to egg deposition is considered an indirect defence strategy that is widespread in the plant kingdom. In recent years, there has been increasing evidence showing that microbial colonization can influence the strength of plant responses to insect herbivory, yet no information is available on how beneficial microbes modulate indirect defences induced by insect egg deposition. In this work, we evaluated the effects of inoculation with the beneficial soil fungus Trichoderma harzianum strain T22 on a tritrophic system consisting of tomato, the southern green stink bug Nezara viridula and its associated egg parasitoid Trissolcus basalis. We used Y‐tube olfactometer assays to evaluate the behavioural responses of the parasitoids to OIPVs emitted by plants colonized with beneficial soil microbes. We also used gas chromatography coupled with mass spectrometry (GC–MS) to investigate whether and how root inoculation with T. harzianum T22 affects the chemical composition of induced plant volatiles. In olfactometer assays, we found that root inoculation with T. harzianum T22 enhanced the attraction of the egg parasitoid towards tomato plants induced by N. viridula feeding and oviposition activities. In particular, the egg parasitoid preferred OIPVs emitted by tomato plants previously inoculated with T. harzianum T22 over OIPVs emitted by non‐inoculated plants. Furthermore, chemical analysis showed that root inoculation with T. harzianum T22 resulted in changes in the composition of OIPVs, which was consistent with the behavioural observations. Among the compounds that strongly contribute to the chemical differences between OIPVs from non‐inoculated and inoculated plants, chemical analysis identified green leaf volatiles ((Z)‐3‐hepten‐1‐ol, (E,E)‐2,4‐hexadienal), along with terpenoids (terpinen 4‐ol, α‐tujene and δ‐elemene). Taken together our results indicate that beneficial soil microbes enhance indirect plant defences induced by feeding and oviposition, broadening our understanding of plant responses to insect eggs. Our results underscore the importance of taking into account the role of microorganisms to fully comprehend the intricate interactions among plants, herbivore eggs and their associated egg parasitoids. Read the free Plain Language Summary for this article on the Journal blog.

Identification and functional marker development of SbPLSH1 conferring purple leaf sheath in sorghum.

We identified a SbPLSH1gene conferring purple leaf sheath in sorghum (sorghumbicolor(L.) Moench)and developed a functional markerfor it. The purple leaf sheath of sorghum, a trait mostly related to anthocyanin deposition, is a visually distinguishable morphological marker widely used to evaluate the purity of crop hybrids. We aimed to dissect the genetic mechanism for leaf sheath color to mine the genes regulating this trait. In this study, two F2 populations were constructed by crossing a purple leaf sheath inbred line (Gaoliangzhe) with two green leaf sheath inbred lines (BTx623 and Silimei). Based on the results of bulked-segregant analysis sequencing, bulk-segregant RNA sequencing, and map-based cloning, SbPLSH1 (Sobic.006G175700), which encodes a bHLH transcription factor on chromosome 6, was identified as the candidate gene for purple leaf sheath in sorghum. Genetic analysis demonstrated that overexpression of SbPLSH1 in Arabidopsis resulted in anthocyanin deposition and purple petiole, while two single-nucleotide polymorphism (SNP) variants on the exon 6 resulted in loss of function. Further haplotype analysis revealed that there were two missense mutations and one cis-acting element mutation in SbPLSH1, which are closely associated with leaf sheath color in sorghum. Based on the variations, a functional marker (LSC4-2) for marker-assisted selection was developed, which has a broad-spectrum capability of distinguishing leaf sheath color in natural variants. In summary, this study lays a foundation for analyzing the genetic mechanism for sorghum leaf sheath color.

The Application of Protein Concentrate Obtained from Green Leaf Biomass in Structuring Nanofibers for Delivery of Vitamin B12.

Nanofibers made of natural proteins have caught the increasing attention of food scientists because of their edibility, renewability, and possibility for various applications. The objective of this study was to prepare nanofibers based on pumpkin leaf protein concentrate (LPC) as a by-product from some crops and gelatin as carriers for vitamin B12 using the electrospinning technique. The starting mixtures were analyzed in terms of viscosity, density, surface tension, and electrical conductivity. Scanning electron micrographs of the obtained nanofibers showed a slight increase in fiber average diameter with the addition of LPC and vitamin B12 (~81 nm to 109 nm). Fourier transform infrared spectroscopy verified the physical blending of gelatin and LPC without phase separation. Thermal analysis showed the fibers had good thermal stability up to 220 °C, highlighting their potential for food applications, regardless of the thermal processing. Additionally, the newly developed fibers have good storage stability, as detected by low water activity values ranging from 0.336 to 0.376. Finally, the release study illustrates the promising sustained release of vitamin B12 from gelatin-LPC nanofibers, mainly governed by the Fickian diffusion mechanism. The obtained results implied the potential of these nanofibers in the development of functional food products with improved nutritional profiles.

The genome sequence of the Green Oak Leaf Roller, Tortrix viridana (Linnaeus, 1758).

We present a genome assembly from a female Tortrix viridana (the Green Oak Leaf Roller; Arthropoda; Insecta; Lepidoptera; Tortricidae). The genome sequence is 456.6 megabases in span. Most of the assembly is scaffolded into 31 chromosomal pseudomolecules, including the Z and W sex chromosomes. The mitochondrial genome has also been assembled and is 16.43 kilobases in length.

Agrochemical Characterization of Podzolic-Yellow Soils Fertilized for a Long Time

It is known from our research that in the last 40-50 years, as a result of intensive use of podzol-yellow soils, the reserve and amount of humus reduced, mechanical composition relatively lightened, but relatively stabilization was observed in humus quantity in the areas where the crop rotation was available. It is known that among the agricultural plants, the standard soil for tea plant — weakly podzolic yellow soil has a score of 100 points on the quality scale. Every year application of mineral fertilizers is required in order to get a lot of green leaf crops from the tea plant bushes in terms of soil-ecological requirements. Therefore, physiological acid ammonium-sulfate fertilizer is applied to bushes at a high dose every year. The super-phosphate fertilizer with more gazh in its composition is applied together with nitrogen fertilizer in order to increase its efficiency. In addition to it, potassium-chlorine or potassium-sulfate is applied. According to the research results it can be noted that humus of moderately washed sort decreased 0,1-1,30%, total nitrogen — 0,07-0,08%, absorbed ammoniac — 20,60-40,14 mg/kg, ammoniac dissolved in water — 1,56-4,38 mg/kg, nitrate – 0,24-2,34 mg/kg, total phosphorus — 0,04-0,05%, gross phosphorus — 2,28-23,54 mg/kg, total potassium — 0,14-0,80 %, exchangeable potassium — 50,0-77,4 mg/kg compared to non-degraded sort.

Chlorophyll Content Evolution of Wheat Triticum aestivum L. var. Alex under Different Salinity Doses

Salinity stress has effects on plants as harmful as those caused by drought. This research aim was to evaluate the changes in wheat total chlorophyll content estimation under salinity stress. The experiment was set up on October 15, 2022, by sowing wheat seeds var. Alex in field conditions, in mezo-phyto-cosmos, under six treatments, 0, 15, 30, 45, 60, and 75 mM NaCl. The total chlorophyll content estimation of leaves, flag leaves, and spikes was measured with a chlorophyll meter. The assessments were taken periodically for leaf greenness during in (Biologische Bundesanstalt, Bundessortenamt und CHemische Industrie) BBCH 11, 14, 51 and at the end of the experiment for flag leaves and spikes greenness. The highest values for leaves total chlorophyll were registered at all treatments except 75 mM NaCl at the fourth evaluation. For flag leaves chlorophyll content, measured at the end of the experiment, the highest value was registered in the control treatment, significantly higher compared to the 15, 45, 60, and 75 mM NaCl by 38%, 86%, 88%, and 91%. The spike chlorophyll content showed no significant differences between all the treatments. Higher doses of saline treatment significantly affect the leaves chlorophyll content, decrease the flag leaf, and spike greenness.

Estimation of Yield Loss Due to Striped Disease in Peanut Plants in Palopo City, South Sulawesi

Palopo City is one of the peanut production centres in South Sulawesi. However, from 2008 to 2020, groundnut production in Palopo City has decreased. Recently, in South Sulawesi, it was reported that peanut stripe virus infection has spread widely and evenly in peanut plants. Symptoms of stripe disease include dark green and light green leaf colour, chlorosis, and can cause stunting. This study aims to determine the estimation of yield loss caused by stripe disease in peanut plants in Polopo City, South Sulawesi. This research was conducted in a farmer-owned groundnut field located in Purangi Village, Sendana Subdistrict, Palopo City, South Sulawesi, from January to May 2023. Parameters observed were plant height, disease severity and incidence, and yield loss. Observations were made 6 times on plants aged 4 to 9 weeks after planting. The results showed that the symptoms of striped disease showed that the growth of peanut plant height was inhibited, and caused a decrease in the number of pods, pod weight, and pod number. Disease severity increased to 57.2% and disease incidence to 46.6%. Yield loss caused by stripe symptoms in peanut plants was 43.78%, indicating that high disease severity and incidence can reduce yield.

BRRI Dhan107: High Protein Premium Quality Rice Variety for Irrigated Ecosystem in Bangladesh

A newly released high protein enriched, premium quality type high yielding, extra-long slender grain containing rice variety BRRI dhan107 which suitable for irrigated ecosystem of Bangladesh, is an improvement over existing high protein enriched and premium quality type rice varieties for Bangladesh. The variety has satisfactorily passed the Proposed Variety Trial (PVT) conducted in the farmers’ field in Boro 2022-23 season. As a result National Seed Board (NSB) approved this variety for commercial cultivation in the Boro season (dry season) in 2024. It has modern plant type with 103 cm plant height and matures by 148 days. The proposed variety showed 1.20 t/ha higher yield than check variety BRRI dhan50. Identifying characters of this variety are green leaf, intermediate plant height, semi-erect flag leaf, extra-long slender grain, intermediate leaf senescence. On an average it can produce 8.19 t/ha grain yield, although with appropriate management under favorable environment it can give up to 9.57 t/ha yield. Thousand grain weight of the variety is 26.1 gm and head rice yield is 60.1%. High protein (10.02%) enriched BRRI dhan107 has high amylose (29.1%) with extra-long slender (7.6 mm) type grain. The high protein enriched, premium quality type rice variety BRRI dhan107 is a superb variety for cultivating in the Boro season (dry) and farmers as well as the country can be nutritionally and economically benefited by the cultivation of BRRI dhan107.

Transcriptomic Analysis of Green Leaf Plants and White-Green Leaf Mutants in Haworthia cooperi var. pilifera.

Haworthia cooperi var. pilifera is a succulent plant with ornamental value. The white-green leaf mutant (wl) showed a significant difference in leaf color from the wild-type plant (WT). In this study, we integrated the transcriptomes of wl and WT plants to screen differentially expressed genes related to leaf color variation. The results of transcriptome analysis showed that 84,163 unigenes were obtained after de novo assembly and the NR database annotated the largest number of unigenes, which accounted for 57.13%, followed by NT (43.02%), GO (39.84%), Swiss-Prot (39.25%), KEGG (36.06%), and COG (24.88%). Our finding showed that 2586 genes were differentially expressed in the two samples, including 1996 down-regulated genes and 590 up-regulated genes. GO analysis predicted that these differentially expressed genes (DEGs) participate in 12 cellular components, 20 biological processes, and 13 molecular function terms and KEGG analysis showed that metabolic pathways, plant-pathogen interaction, glycerophospholipid metabolism, endocytosis, plant hormone signal transduction, and ether lipid metabolism were enriched among all identified pathways. Through functional enrichment analysis of DEGs, we found that they were involved in chloroplast division and the biosynthesis of plant pigments, including chlorophyll, carotenoids, anthocyanin, and transcription factor families, which might be related to the formation mechanism of leaf color. Taken together, these results present insights into the difference in gene expression characteristics in leaves between WT and wl mutants and provide a new insight for breeding colorful leaf phenotypes in succulent plants.

Anti-black pod disease activity of leaf extract of Carica papaya Linn

BackgroundTheobroma cacao (Cocoa) is a major foreign exchange earner for Ghana. Over the recent decades, there has been a consistent decline in cocoa production in the country. A major contributing factor is the cocoa black pod disease caused by Phytophthora species. Synthetic fungicides have been used to control the pathogens over the years. However, recent calls for organic cocoa devoid of residues from synthetic fungicides, which are known to pose several health challenges as well as a negative impact on the environment, have gained attention. Thus, inviting investigations into more environmentally friendly and sustainable alternatives to synthetic fungicides. ObjectiveThis study explored the inhibitory potential of crude extract from Carica papaya against cocoa black pod disease caused by Phytophthora spp. Material and methodsAn in-silico study was done using known phytochemicals from Carica papaya as ligands against a Phytophthora effector protein. Crude extracts were obtained from the plant materials using 70 % ethanol as the extraction solvent. The crude Green Leaf Extract (GLE), Aging Induced Chlorophyll Deficient Leaf Extract (AICDLE), and Matured Black Seed Extract (SDE) were tested in-vitro against pre-cultured P. palmivora and P. megakarya using the poison food technique. GLE was modulated with Delco, a synthetic fungicide, at different ratios which were tested in-vitro and in-vivo. ResultsA total of 16 ligands showed binding affinity higher or equal to the standard ligand, alliin, suggesting Carica papaya as a repository of anti-phytophthora agents. Assessment of crude extracts at concentrations 5–20 mg/ml showed fungistatic activity against P. palmivora and P. megakarya in-vitro. Modulation of GLE with Delco produced some combinations that made GLE fungicidal in-vitro against P. palmivora and P. megakarya with fractional inhibition concentration indices between 0.51 and 0.65, interpreted as partially synergistic. The in-vivo assessment of combination D (Delco and GLE in a 0.3 mg:3 mg per ml ratio) performed as well as Delco alone at the recommended dose of 5 mg/ml. Thus, combination D reduces the requirement for copper-based fungicide by over 90 %. ConclusionThis study shows Carica papaya in a new light as a potential material that could be formulated into a natural product-based fungicide for combating Phytophthora-induced black pod disease.

Tritrophic Interactions Mediated by Zoophytophagous Predator-Induced Host Plant Volatiles.

The zoophytophagous mirid predator Nesidiocoris tenuis and the ectoparasitoid Stenomesius japonicus are important biological control agents for several agricultural pests including the invasive leafminer, Phthorimaea absoluta, a destructive pest of Solanaceous crops especially tomato in sub-Saharan Africa. However, little is known about how feeding by N. tenuis can influence the tritrophic interactions in the tomato plant. Here, we tested the hypothesis that N. tenuis phytophagy would influence the tritrophic olfactory interactions between the host plant tomato and pest, predator, and parasitoid. In olfactometer assays, P. absoluta females and N. tenuis adults were both attracted to constitutive volatiles released by the tomato plant. Whereas females of P. absoluta avoided volatiles released by N. tenuis-infested plants, S. japonicus females and N. tenuis adults were attracted to the induced volatiles. In coupled gas chromatography-electroantennographic detection (GC-EAD) recordings of intact and N. tenuis-infested plant volatiles, antennae of P. absoluta and S. japonicus females both detected eight components, whereas N. tenuis adults detected seven components which were identified by GC-mass spectrometry (GC-MS) as terpenes and green leaf volatiles (GLVs). Dose-response olfactometer bioassays revealed that the responses of P. absoluta, N. tenuis, and S. japonicus varied with the composition and concentration of blends and individual compounds tested from N tenuis-induced volatiles. Females of P. absoluta showed no preference for an eight-component blend formulated from the individual repellents including hexanal, (Z)-3-hexenyl butanoate, and δ-elemene identified in the volatiles. On the other hand, S. japonicus females were attracted to an eight-component blend including the attractants (E)-2-hexenal, (Z)-3-hexenol, methyl salicylate, β-phellandrene, and (E)-caryophyllene. Likewise, N. tenuis adults were attracted to a seven-component blend including the attractants β-phellandrene, δ-elemene, and (E)-caryophyllene identified in the volatiles. Our findings suggest that there is potential for the use of terpenes and GLVs to manage the insects in the tritrophic interaction.

Effects of Organic Amendments on the Morphology and Chemical Composition of Black Mustard (Sinapis nigra L.) Grown on Soil Contaminated with Copper

The present study aimed to determine the influence of organic amendments (OAs) on neutralizing the harmful effect of copper (Cu) on black mustard (Sinapis nigra L.). In a pot experiment, three levels of copper pollution were used: 200, 400, and 600 mg Cu kg−1, against a control without Cu. The soil was amended with three types of OAs: pine bark (PB), peat moss (PM), and cattle manure (CM). Our research showed that plant condition depends on the Cu content in the soil. Increasing soil contamination significantly affected the plant yield, leaf greenness index, and dry matter content. The type of OA had no significant effect on the condition of black mustard (BM); however, each had a different effect on neutralizing the harmful effects of Cu. CM reduced Cu accumulation, PM showed no effect, while PB contributed to a significant increase in Cu content in BM plants. The chemical composition of BM depended on the Cu content in the soil. With increased soil contamination with Cu, the contents of Ntot, K, Mg, Ca, and Na in BM increased, while the content of P decreased. In terms of mitigating the harmful effects, CM was more beneficial than PM and PB. Among the analyzed OAs, CM, and PM contributed to Cu immobilization, while PB promoted Cu mobilization in contaminated soils.