Substrates, emergence and initial development of passion fruit seedlings

Passion fruit is known to be sensitive to drought, and in order to study the physiological and biochemical changes that occur in passion fruit seedlings under drought stress, a hypertonic polyethylene glycol (PEG) solution (5%, 10%, 15%, and 20%) was used to simulate drought stress in passion fruit seedlings. We explored the physiological changes in passion fruit seedlings under drought stress induced by PEG to elucidate their response to drought stress and provide a theoretical basis for drought-resistant cultivation of passion fruit seedlings. The results show that drought stress induced by PEG had a significant effect on the growth and physiological indices of passion fruit. Drought stress significantly decreased fresh weight, chlorophyll content, and root vitality. Conversely, the contents of soluble protein (SP), proline (Pro), and malondialdehyde (MDA) increased gradually with the increasing PEG concentration and prolonged stress duration. After nine days, the SP, Pro and MDA contents were higher in passion fruit leaves and roots under 20% PEG treatments compared with the control. Additionally, with the increase in drought time, the activities of antioxidant enzymes such as peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT) showed an increasing trend and then a decreasing trend, and they reached the highest value at the sixth day of drought stress. After rehydration, SP, Pro and MDA contents in the leaves and roots of passion fruit seedlings was reduced. Among all the stress treatments, 20% PEG had the most significant effect on passion fruit seedlings. Therefore, our study demonstrated sensitive concentrations of PEG to simulate drought stress on passion fruit and revealed the physiological adaptability of passion fruit to drought stress.

The quality of soybean seeds is influenced by the amount of nutrients that are available for the germination and initial development of the seedlings. Thus, the aim of this research was to evaluate the influence of the nutritional content of the seeds and mineral supplementation via seed treatment on physiological quality, enzymatic activity and initial development of soybean seedlings. We assessed soybean seeds from two lots with low and high nutritional content, submitted or not to mineral supplementation via seed treatment. The physiological quality of seeds was assessed by the germination test and first germination count. The initial development of seedlings was evaluated by the tests of length and root system volume, shoot length, and cotyledons, roots and shoot dry matter. It was also determined the activity of α-amylase in cotyledons, acid phosphatase (APase) and guaiacol peroxidase (POD) in the roots and shoot. Mineral supplementation via seed treatment positively influenced the physiological quality and development of seedlings, and the activity of α-amylase in the cotyledons, POD and APase enzymes in the shoot from the low nutrient lot. Low nutrient seeds have characteristics of soybean seedling production similar to those of high nutrient content by using mineral supplementation via seeds.

Este trabalho objetivou avaliar os efeitos da adubação com N e K no desenvolvimento de mudas de maracujazeiro-amarelo (Passiflora edulis) cultivadas em Latossolo Vermelho distrófico. O delineamento experimental foi o inteiramente casualizado, com três repetições, num esquema fatorial 4 x 4, com 4 doses de N (zero, 150, 300 e 600mg de N dm-3) e quatro de K (zero, 75, 150 e 300mg de K dm-3), parceladas em quatro vezes. A unidade experimental foi constituída por vasos de 3,3L. Após 84 dias da germinação, foram avaliados: altura da planta, o diâmetro do caule, o número de folhas e a área foliar. O melhor desenvolvimento das mudas de maracujazeiro ocorreu com as doses de 150mg de N dm-3 e de 300mg de K dm-3.

Passion fruit (Passiflora edulis f. flavicarpa) has high economic and nutritional value, and the nursery stage is crucial for its early development. The objective of the present study was to evaluate chlorophyll fluorescence, foliar nutritional status, and growth of passion fruit seedlings in response to four organic substrates: S1 (sand + biochar + organic matter), S2 (sand + compost + organic matter), S3 (sand + compost + agricultural soil), and S4 (agricultural soil), under a completely randomized design. The physiological variables Fv/Fm, Φ(II), and ETR were measured, as well as the foliar concentration of macro and micronutrients and growth variables, whose data were analyzed using ANOVA and Tukey's test (5%). Plants grown in substrate S2 showed the highest photochemical efficiency (Fv/Fm ≈ 0.79; Φ(II) ≈ 0.44; ETR ≈ 160), whereas those in substrate S1 exhibited the highest foliar concentrations of K, Fe, and Zn. The principal component analysis explained 71% of the total variability, associating substrate S2 with better physiological yield and growth. It can be concluded that substrates containing compost enhance PSII photochemical efficiency, while those including biochar are associated with greater foliar mineral accumulation.

Passion fruit (Passiflora edulis Sims) is widely cultivated in tropic and sub-tropic regions for the production of fruit, flowers, cosmetics, and for pharmacological applications. Its high economic, nutritional, and medical values elicit the market demand, and the growing areas are rapidly increasing. Leaf blight caused by Nigrospora sphaerica is a new and emerging disease of passion fruit in Guizhou, in southwest China, where the unique karst mountainous landscape and climate conditions are considered potential areas of expansion for passion fruit production. Bacillus species are the most common biocontrol and plant-growth-promotion bacteria (PGPB) resources in agricultural systems. However, little is known about the endophytic existence of Bacillus spp. in the passion fruit phyllosphere as well as their potential as biocontrol agents and PGPB. In this study, 44 endophytic strains were isolated from 15 healthy passion fruit leaves, obtained from Guangxi province, China. Through purification and molecular identification, 42 of the isolates were ascribed to Bacillus species. Their inhibitory activity against N. sphaerica was tested in vitro. Eleven endophytic Bacillus spp. strains inhibited the pathogen by >65%. All of them produced biocontrol- and plant-growth-promotion-related metabolites, including indole-3-acetic acid (IAA), protease, cellulase, phosphatase, and solubilized phosphate. Furthermore, the plant growth promotion traits of the above 11 endophytic Bacillus strains were tested on passion fruit seedlings. One isolate, coded B. subtilis GUCC4, significantly increased passion fruit stem diameter, plant height, leaf length, leaf surface, fresh weight, and dry weight. In addition, B. subtilis GUCC4 reduced the proline content, which indicated its potential to positively regulate passion fruit biochemical properties and resulted in plant growth promotion effects. Finally, the biocontrol efficiencies of B. subtilis GUCC4 against N. sphaerica were determined in vivo under greenhouse conditions. Similarly to the fungicide mancozeb and to a commercial B. subtilis-based biofungicide, B. subtilis GUCC4 significantly reduced disease severity. These results suggest that B. subtilis GUCC4 has great potential as a biological control agent and as PGPB on passion fruit.

The yellow passion fruit is a plant climbing botanically that has a good geographical distribution in Brazil, with more than 150 species in the country. The presence of salts in soil and irrigation water is one of the main obstacles in agriculture in the world, caused by low rainfall and high evapotranspirative rates causing the salts to accumulate in the soil. However, alternatives have been sought to try to mitigate such limitations of seedling production, such as the use of biofertilizers in the soil. In this way, the objective was to evaluate the growth and development of yellow passion fruit seedlings under the effects of irrigation water salinity and the use of bovine biofertilizer on the substrate. An experiment was carried out in a greenhouse in the Center for Agrarian Sciences and Biodiversity, from october/2017 tomarch/2018, in county of Crato-Ceara, Brazil. The substrate used was the first 20 cm material of a yellow Red Argisol. The experimental design was completely randomized design (C.R.D) in a factorial scheme 5x2, referring to the electrical conductivity values ​​of the irrigation water: 0.5; 1.0; 2.0; 3.0 and 4.0 dS m-1, in the soil without and with common biofertilizer, with three replicates. The biofertilizer, after being diluted in non-saline water (0.5 dS m-1) in the ratio of 1:3, was applied only once to 10% of the substrate volume two days before sowing. The increase in the salinity of irrigation water negatively affected the initial behavior of the passion fruit seedlings in terms of growth and development, especially in the treatments that did not receive the organic feed.

The rice crop is annual, adapted to highlands, floodplains or flooded, representing high importance for human consumption, requiring research for the optimization of cultivation and its initial development. The objective of the present work was to evaluate the germination and vigor of rice seeds, with the application of inoculant with bacteria of the species Azospirillum brasilense. The experimental design used was completely randomized, using six inoculant doses containing A. brasilense, with 4 replications of 50 seeds each, using the SCS 121 CL cultivar. Germination evaluations were carried out daily up to 14 days, the first count test on the 5th day and the second count on the 14th day after sowing. The germination speed index and the biometric parameters were also performed at the end of the experiment. The dose of 4.0 mL 1000-1 seeds of inoculant was the treatment that resulted in a percentage of germination in the rice seed. Root length increased with higher doses, however there was no significant difference in root dry mass. The different inoculant doses do not interfere with the development of the rice aerial part.

The effects of two farm manures, bovine manure (BM) and chicken manure (CM), on imazaquin degradation in a sandy loam soil were studied under laboratory conditions. The degradation of imazaquin in BM and CM-amended soil (10% by w/w) was about 2.4 and 1.5 times, respectively, faster than that in unamended soil. Different amendment ratios of BM to soil lead to different degradation rates of imazaquin. However, higher mix ratio did not necessarily increase the degradation, and the optimal active degradation of imazaquin was observed at the approximate mix ratio of 10:1 of soil to BM. Imazaquin degradation rate was enhanced 2∼ 4 times in non-sterilized soil over that in SGI (sterilization by gamma irradiation) soil. In non-sterilized soil, biological mechanisms accounted for 48.7% to 74.6% of imazaquin degradation, which suggested that microbial transformation was the primary pathway for imazaquin degradation in soil. The degradation rate of imazaquin for SSA (sterilization by sodium azide) treatment was 1.33 and 1.26 times, respectively, over that for SA (sterilization by autoclaving) and SGI treatments. Imazaquin degradation half-life (13.2 d) in SGI soil with non-sterilized BM was 3.2 times faster than that in SGI soil without BM. In contrast, the slow degradation rate (0.0173 d−1) was observed in SGI soil with water-extracted nutrients from sterilized BM. The organic matter and water-extracted nutrients from sterilized manure had no effects on imazaquin degradation in soil.

IntroductionThe production ofpapaya seedlings is one of the main steps for establishing crops that present maximum quality performance. Nutritional availability is one of the factors limiting the formation process of quality seedlings, and fertilization is often done without technical criteria. Thus, the objective of this study was to evaluate the effect of different doses of Lithothamnion sp., obtained from different sources, on the development and growth of ’Aliança‘ papaya seedlings.MethodsThe study was developed at the Experimental Farm of the Capixaba Institute of Research, Technical Assistance, and Rural Extension, in the municipality of Linhares, north of the state of Espírito Santo. The experimental design used was randomized blocks in a factorial scheme, where the first factor was composed of three commercial sources of Lithothamnion sp. (LT Supra®; Algen® and Primaz®). The second factor was composed of six different doses, namely: 0; 2; 4; 6; 8; and 10 kg m-3 of Lithothamnion sp. At 37 days after sowing, the seedlings were evaluated for the following characteristics: germination percentage; leaf area; stem length; stem mass fraction; root length; stem diameter; leaf dry mass; stem dry mass; root dry mass; and total dry mass. The content of nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur in the leaves and roots was also evaluated.ResultsThe use of Lithothamnion sp. on ’Aliança‘ papaya seedlings promoted leaf and stem growth and development, dry matter accumulation, and improved germination percentage. Lithothamnion sp. from the coast of Espírito Santo (LT supra®) promoted significant gains in germination percentage, leaf area, stem length, root collar diameter, leaf dry matter, stem dry matter, and total dry matter. Lithothamnion sp. from the coast of Maranhão (Algen®) and Bahia (Prima®) increased leaf phosphorus and root sulfur levels.DiscussionLithothamnion sp. promoted a biostimulant effect with improved growth and development in ’Aliança‘ papaya seedlings, with a dosage close to 4 kg m-3, with the LT supra® product being the most recommended.

The aim of this work was to evaluate the physiological parameters and development of passion fruit submitted to water stress and propagation methods. The experiment was conducted in a completely randomized design (DIC), in a 3x3 factorial arrangement, using methods of propagation (PM) of passion fruit, which are: the species Passiflora edulis propagated with seeds (PS); Passiflora edulis grafted on the Passiflora gibertii species propagated by seed (E x PS) and Passiflora edulis grafted on the Passiflora gibertii species propagated by cuttings (E x PE) and interacting with three irrigation intervals (I), which are irrigated with intervals of 4, 8 and 12 days, with four repetitions. The suspension of irrigations for eight days reduces the rate of CO2 assimilation, transpiration and stomatal conductance in passion fruit seedlings propagated by seeds and grafting. Passion fruit plants propagated by seeds show greater efficiency in the use of water than those grafted on P. gibertii. Passion fruit seedlings grafted onto seedlings obtained by cuttings or seeds have vigor to be propagated commercially.

To accelerate growth performance of Robusta coffee (Coffea canephora) seedling could be conducted through the application of exogenous plant hormone.Salicylic acid is one of plant hormones that widely applied to increase the plant growth for several plants, however, for coffee was still relative limited. This studywas aimed to determine the effect of salicylic acid on the growth of Robusta coffee seedlings which research was conducted at Indonesian Coffee and CocoaResearch Institute (ICCRI), Jember, East Java. This experiment was set using split plot design with three replications. The main plot was clones, which were BP 308and Sintaro clones. The seedlings were propagated from rooted cuttings. The subplot was the concentration of exogenous salicylic acid, that were control,0.6 mM, 1.2 mM, and 1.8 mM. The result demonstrated that BP 308 clone had higher rooting performance than Sintaro clone that shown by the higher rootvolume, root dry mass, and root/shoot ratio. In general, the application of salicylic acid could enhance the growth of Robusta coffee seedling. The application of 0.6 mMsalicylic acid increased plant growth of coffee seedlings. There was different response to concentration of application salicylic acid for both clones. The application of 0.6 mM salicylic acid could increase plant growth of BP 308, includeplant height, leaf area, stem dry mass, leaf dry mass, root/shoot ratio and total dry mass. Meanwhile, on Sintaro clone, application of 1.2 mM salicylic acid couldincrease leaf area, stem, leaf and total dry mass. The application of salicylic acid more than 1.2 mM led to detrimental effect of coffee seedlings.

Surveys were conducted to determine the occurrence of diseases of yellow passion fruit (Passiflora edulis f. flavicarpa) in plantations located in the central states of Aragua, Carabobo, Guarico, Miranda, and Yaracuy, Venezuela, from 1991 to 1998. Plants in both commercial plantations and passion fruit nurseries were symptomatic for wilt and reddish-brown collar rot. Symptomatic tissues were surface-disinfected and plated on PARPH medium (1). Phytophthora parasitica was frequently isolated from diseased tissues, and pathogenicity tests were conducted with the fungus under greenhouse conditions. Passion fruit seedlings were grown in pots containing a 1:1 (vol/vol) steamed soil/sand mixture, one plant per pot. Five-millimeter-diameter plugs of P. parasitica isolates were grown on clarified V8 agar. Three-month-old seedlings were wounded with a sterile scalpel in the collar region. Wounded and unwounded plants were inoculated with 10 ml of zoospore suspension (105 spores per ml) or sterile water (control). Fifty plants were evaluated per treatment, and the experiment was repeated. Wounded and unwounded seedlings inoculated with zoospores developed chlorosis and collar necrosis after 15 days. Seedling mortality reached 50% 1 month after inoculation, and the fungus was reisolated from symptomatic tissues. This is the first report of P. parasitica causing collar rot and wilt of yellow passion fruit in Venezuela. Reference: (1) S. N. Jeffers and S. B. Martin. Plant Dis 70:1038, 1986.

O aproveitamento de água residuária de suinocultura, além de servir como fonte de nutrientes, constitui-se numa prática de reutilização da água, evitando a poluição de água e do solo. Com esse intuito, foi instalado e conduzido um experimento aproveitando a água residuária de suinocultura para o desenvolvimento de mudas de maracujazeiro-azedo visando a suprir a necessidade de fertilizantes comerciais. Foi utilizado o esquema fatorial 5 x 2, no delineamento de blocos casualizados, sendo os fatores: as concentrações de água residuária de suinocultura (0; 25; 50; 75 e 100%) e os tipos de substrato (comercial e a mistura de terra+areia, na proporção v/v de 2:1), com 4 repetições e sete plantas por parcela. Após 60 dias, foram avaliadas as seguintes características: comprimento da parte aérea e do sistema radicular (cm), número de folhas, área foliar (cm²), matéria seca da parte aérea e do sistema radicular (mg) e análise foliar e de fertilidade do substrato terra+areia. O melhor desenvolvimento das mudas de maracujazeiro-azedo ocorreu com a aplicação da água residuária de suinocultura na concentração de 100%. A utilização da água residuária supriu a demanda nutricional de mudas de maracujazeiro-azedo na fase inicial, sem o fornecimento de fertilizantes comerciais. A utilização de substratos mais porosos, como o Plantmax, favoreceu o desenvolvimento de mudas de maracujazeiro-azedo.

Host bacterial community of MGEs determines the risk of horizontal gene transfer during composting of different animal manures

We evaluated the effect of crude extracts of the microcystin-producing (MC+) cyanobacteria Microcystis aeruginosa on seed germination and initial development of lettuce and arugula, at concentrations between 0.5 μg.L(-1) and 100 μg.L(-1) of MC-LR equivalent, and compared it to crude extracts of the same species without the toxin (MC-). Crude extracts of the cyanobacteria with MC (+) and without MC (-) caused different effects on seed germination and initial development of the salad green seedlings, lettuce being more sensitive to both extracts when compared to arugula. Crude extracts of M. aeruginosa (MC+) caused more evident effects on seed germination and initial development of both species of salad greens than MC-. Concentrations of 75 μg.L(-1) and 100 μg.L(-1) of MC-LR equivalent induced a greater occurrence of abnormal seedlings in lettuce, due to necrosis of the radicle and shortening of this organ in normal seedlings, as well as the reduction in total chlorophyll content and increase in the activity of the antioxidant enzyme peroxidase (POD). The MC- extract caused no harmful effects to seed germination and initial development of seedlings of arugula. However, in lettuce, it caused elevation of POD enzyme activity, decrease in seed germination at concentrations of 75 μg.L(-1) (MC-75) and 100 μg.L(-1) (MC-100), and shortening of the radicle length, suggesting that other compounds present in the cyanobacteria extracts contributed to this result. Crude extracts of M. aeruginosa (MC-) may contain other compounds, besides the cyanotoxins, capable of causing inhibitory or stimulatory effects on seed germination and initial development of salad green seedlings. Arugula was more sensitive to the crude extracts of M. aeruginosa (MC+) and (MC-) and to other possible compounds produced by the cyanobacteria.