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Au Trung Vo, Imane Haddidi, Hussein Daood, Zoltan Mayer and Katalin Posta

The aim of this study was to determine the influence of mycorrhizal inoculation and sand-peat composition as growth substrate on the biomass, and individual polyphenol concentration of Eclipta prostrata. Mycorrhizal inoculation alters some secondary metabolites of E. prostrata, showing significant differences in polyphenol contents between the treatments. Moreover, varying peat and sand rates, representing different nutrient supplies, had significant impacts on both mycorrhizal colonization and growth responses. Our results highlight that 60/40% (v/v) sand and peat ration is the best for a large-scale cultivation of E. prostrata, moreover supporting the highest total phenolic content. Through high-performance liquid chromatography (HPLC) analysis, nine individual phenolic components were analyzed, including wedelolactone and demethyl-wedelolactone at the highest concentration. Some of the identified compounds, such as 5-o-caffeoylquinic acid, quercetin-3-arabinoside, 4-o-caffeoylquinic acid, and protocatechuic acid have not been reported previously in E. prostrata cultivars. Using hierarchical cluster analysis, multiple groups are represented, suggesting the role of mycorrhizal inoculation, growth substrate, and their interaction on secondary metabolites of E. prostrata. Better understanding of the phenolic composition of E. prostrata and factors influencing it help to identify new industrial applications of this medicinal plant (together with arbuscular mycorrhizal fungi), and moreover, help to develop new strategies for the prevention and treatment of different diseases.

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İbrahim Kahramanoğlu and Serhat Usanmaz

The present study was conducted with the aim of increasing storage duration of cucumber fruits by using eco-friendly edible biomaterials and nanotechnology. Hence, the effects of postharvest-applied lemongrass oil (LO) and propolis extract (PEx), alone or in combination with modified atmosphere packaging (MAP), on the weight loss, fruit firmness, sensory index, chilling injury (CI), decay incidence (DI), and soluble solid concentration (SSC) of cucumber fruits were tested. Two different doses (0.2% and 0.5%) of both LO and PEx were tested in present study. Application of LO and PEx was performed by dipping the fruits into the solutions at 21 ± 1 °C for 3 minutes; after drying for 30 minutes, fruits were transferred to a cold room and kept at 4.5 ± 0.5 °C and 95% relative humidity (RH). Studies were continued for 24 days, and quality parameters were measured at 4-day intervals. Two-day shelf-life simulation was also applied to fruits after each interval, and the same quality parameters were observed. Results suggest that the combination of MAP bags with LO or PEx treatment provides better conditions for postharvest storage of cucumbers and that storage duration might be extended to 20 days. Fruits treated with LO or PEx and stored in MAP bags maintained weight and SSC, were firmer, showed lower DI, and expressed lower CI (P < 0.05) throughout storage.

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Yuee Tian, Zhiping Che, Di Sun, Jiaxuan He, Shengming Liu and Xiaomin Lin

Gray mold caused by Botrytis cinerea has become an important limiting factor for tree peony production. Currently, chemical control is still the main means of managing the disease in China. The objective of this study was to test fungicides with different mechanisms of action in controlling B. cinerea on tree peony. The inhibitory efficacy of five fungicides on four asexual stages was measured in the petri dish containing culture medium amended with a tested fungicide at various concentrations. The results showed that carbendazim had the strongest inhibition effect against all four stages of B. cinerea, with the EC50 values of 0.1037, 0.0563, 0.5578, and 0.0797 mg·L–1, respectively. The inhibitory effect of diethofencarb was only slightly less than that of carbendazim on conidia production, germination, and germ tube elongation. The inhibitory effect of procymidone was second only to that of carbendazim on colony expansion. The results indicated that carbendazim and diethofencarb could be used as protective fungicides to spray in the early stage of disease occurrence to inhibit conidia germination and germ tube elongation, so as to reduce the infection rate of B. cinerea and prevent disease occurrence. Carbendazim, procymidone, and diethofencarb mainly inhibit the reinfection of B. cinerea by inhibiting the growth of mycelium and the production of conidia, so they could be used as control fungicides during the occurrence phase of the disease.

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Philip J. Brown, Lambert B. McCarty, Virgil L. Quisenberry, L. Ray Hubbard Jr. and M. Brad Addy

Drainage is important to golf and athletic facilities trying to avoid lost play time. Native soil containing clay is sometimes incorporated into sand profiles with the intent to increase water and nutrient holding capacities. However, mixes high in silt and/or clay often have drainage problems. Research was conducted on soil physical properties from incremental 10% v/v additions of silt and clay (fines) to a U.S. Golf Association (USGA)-specification sand. Soils were evaluated based on volumetric water retention from 0 to 50 cm matric potential, saturated hydraulic conductivity (Ksat), porosity, and bulk density. The soil water characteristic (SWC) for 100:0 (sand:fines) had lower volumetric water content (θv) throughout the profile than any other mixture. Addition of 10% fines increased θv to more than 0.17 cm3·cm–3 throughout the 0- to 50-cm matric potential range, whereas 20% fines increased θv to more than 0.26 cm3·cm–3. The 70:30 mixture had greater θv throughout the profile than mixtures containing more than 70% sand. Mixtures with less than 70% sand produced similar SWCs. Increasing sand content increased bulk density, which altered saturated volumetric water content. Ksat was reduced from more than 265 cm·h–1 in 100:0 mixtures to 43 cm·h–1 for 90:10 mixtures, and to less than 5 cm·h–1 with ≥20% fines. The addition of ≥20% by volume of fines to a USGA sand increased water content in the soil to the point it was rendered unacceptable for trafficked turf sites. This research illustrates the influence fine particles, even in small amounts, can have on a USGA sand, and why they should not be added without prior evaluation.

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Guilherme Locatelli, Rafael Pio, Rayane Barcelos Bisi, Filipe Bittencourt Machado de Souza, Mariana Thereza Rodrigues Viana, Daniela da Hora Farias, Evaristo Mauro de Castro and Carolina Ruiz Zambon

Water deficits are considered the primary environmental stress in agriculture, and improving the growth and production of plants under this stress is one of the primary goals of breeding and crop management programs. The apple tree is a plant that is negatively affected by water stress. Plants that develop under a water deficit may develop physiological and anatomical strategies to survive or even produce fruits in these environments. In view of the importance of and lack of studies of the leaf anatomy of apple trees in areas with a water deficit that are intended to support genetic improvement programs for this fruit either to introduce cultivars in regions with water deficits or to select potential progenies for future crosses, the aim of this study was to compare the anatomical characteristics of apple leaves from two distinct environments (water deficit and precipitation) under tropical conditions. Twelve fully expanded leaves were collected from seven apple cultivars (Eva, Rainha, Princesa, Julieta, Imperatriz, Baronesa, and Gala Real), which are planted in the experimental orchard at Universidade Federal de Lavras, during water deficit (September) and precipitation (February) seasons. Sixteen anatomical characteristics were evaluated in addition to the anatomical description of the apple leaves. The experimental design was completely randomized in a 7×2 factorial arrangement. The means were analyzed using the Scott-Knott method for grouping means at the 5% level of error probability. Genetic divergence, cultivar clustering and principal component analyses were also performed based on the anatomical characteristics evaluated during the two seasons. The apple leaves had anatomical characteristics that can favor the production of this fruit tree in areas experiencing water deficits within subtropical regions. According to their anatomical characteristics, there was genetic divergence among the apple cultivars studied here. The cultivars Gala Real, Eva, and Baronesa presented anatomical and morphological characteristics that showed adaptation potential in areas with water deficits.

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Yan Liu, Hailin Guo, Yi Wang, Jingang Shi, Dandan Li, Zhiyong Wang and Jianxiu Liu

Seashore paspalum (Paspalum vaginatum) is a notable warm-season turfgrass. Certain germplasm resources are distributed in the southern regions of China. The objectives of this study were to investigate the genetic diversity and genetic variation of Chinese seashore paspalum resources. Morphological characteristics and sequence-related amplified polymorphism (SRAP) markers were used to assess genetic relationships and genetic variation among 36 germplasm resources from China and six cultivars from the United States. The results showed significant variation for 13 morphological characteristics among 42 tested seashore paspalum accessions, and that the phenotypic cv was, in turn, turf height > turf density > internode length > inflorescence density > leaf width > reproductive branch height > spikelet width > leaf length > spikelet number > inflorescence length > internode diameter > inflorescence width > spikelet length. According to the morphological characteristics and cluster analysis, 42 seashore paspalum accessions were divided into six morphological types. In total, 374 clear bands were amplified using 30 SRAP primer combinations; among these bands, 321 were polymorphic with 85.83% polymorphism. SRAP marker cluster analysis showed that 42 seashore paspalum accessions were grouped into seven major groups, with a genetic similarity coefficient ranging from 0.4385 to 0.9893 and genetic distance values ranging from 0.0108 to 0.8244. The high level of genetic diversity occurred among Chinese germplasm, and the genetic distance was relatively high between Chinese germplasm and cultivars introduced from the United States. The patterns in morphological trait variations and genetic diversity will be useful for the further exploitation and use of Chinese seashore paspalum resources.

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Mokhles A. Elsysy and Peter M. Hirst

Adequate flower formation limits dependable apple (Malus ×domestica) production and is a major challenge for apple industries around the world. ‘Honeycrisp’ is a high value apple cultivar, but consistent flowering is difficult to achieve. Apple flower formation is affected by factors including defoliation, girdling, and gibberellin (GA4+7) and 1-naphthaleneacetic acid (NAA) applications. However, the molecular mechanisms that regulate the effects of these factors are not well understood. We studied the effect of local spur defoliation, GA4+7 and NAA applications on ‘Honeycrisp’ flower formation. Furthermore, we investigated the effect of local defoliation and local GA4+7 application on the transcript levels of two major flower formation genes in the meristems of apple spurs. The floral inhibition gene terminal flower1-1 (MdTFL1-1) and floral promoting genes flowering locus T (MdFT1 and MdFT 2) of apple. Local application of GA4+7 and defoliation treatments inhibited flower formation, but NAA applications were without effect. Defoliation treatments were accompanied by a significant reduction in MdFT1, 2 transcript levels compared with controls early in the growing season. Conversely, GA4+7 application was accompanied by a significant increase in MdTFL1-1 transcripts compared with controls throughout the growing season. These results indicate that GA4+7 inhibits flower formation by upregulating the inhibitory MdTFL1-1, and defoliation acts by downregulating transcript levels of MdFT1, 2 early in the growing season. We also provide evidence that defoliated bourse buds may receive flowering promotion signals from other parts of the tree in the absence of their local leaves.

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Desire Djidonou, Xin Zhao, Karen E. Koch and Lincoln Zotarelli

Growth and yield typically increase when tomato plants are grafted to selected interspecific hybrid rootstocks from which distinctive root system morphologies are envisioned to aid nutrient uptake. We assessed these relationships using a range of exogenous nitrogen (N) supplies under field production conditions. This study analyzed the impact of N on growth, root distribution, N uptake, and N use of determinate ‘Florida 47’ tomato plants grafted onto vigorous, interspecific, hybrid tomato rootstocks ‘Multifort’ and ‘Beaufort’. Six N rates, 56, 112, 168, 224, 280, and 336 kg·ha−1, were applied to sandy soil in Live Oak, FL, during Spring 2010 and 2011. During both years, the leaf area index, aboveground biomass, and N accumulation (leaf blade, petiole, stem, and fruit) responded quadratically to the increase in N fertilizer rates. Averaged over the two seasons, the aboveground biomass, N accumulation, N use efficiency (NUE), and N uptake efficiency (NUpE) were ≈29%, 31%, 30%, and 33% greater in grafted plants than in nongrafted controls, respectively. More prominent increases occurred in the root length density (RLD) in the uppermost 15 cm of soil; for grafted plants, RLD values in this upper 15-cm layer were significantly greater than those of nongrafted plants during both years with an average increase of 69% over the two seasons. Across all the grafted and nongrafted plants, the RLD decreased along the soil profile, with ≈60% of the total RLD concentrated in the uppermost 0 to 15 cm of the soil layer. These results demonstrated a clear association between enhanced RLD, especially in the upper 15 cm of soil, and improvements in tomato plant growth, N uptake, and N accumulation with grafting onto vigorous rootstocks.

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Manpreet Singh, Rupinder Kaur Saini, Sukhbir Singh and Sat Pal Sharma

Water shortage is one of the major challenges faced by the current agricultural systems worldwide, especially in arid and semi-arid regions. Deficit irrigation (DI), a water-saving strategy of applying less water than crop evapotranspiration (ETc) demands, has been extensively investigated in different crops, including water-intensive vegetables. The DI strategies such as regulated deficit irrigation (RDI) and partial root zone drying (PRD) generally increase water use efficiency (WUE) and have emerged as potential practices to save water for agricultural sustainability. However, in view of the sensitivity of shallow-rooted vegetable crops to water stress, DI is often associated with yield losses. A review of 134 DI reports of vegetable crops revealed significant reductions in yield under all DI levels in 52% of cases and yields statistically similar to those of full irrigation (100% ETc in most cases) under small water deficits in 44% of cases, thereby raising concerns about the sustainability of vegetable production under DI. Biochar, a carbon-rich co-product of pyrolysis of organic matter, is increasingly undergoing study as a soil amendment to mitigate drought stress and is being explored as an additional practice with DI to minimize the yield losses due to water deficits. This work reviews the effects of biochar application on growth, yield, physiology, and WUE of different vegetable crops under DI regimes to determine the potential of biochar and DI used in combination to sustain vegetable productivity in water-limited areas. Overall, the addition of biochar under DI has helped to compensate for yield losses of vegetables and further enhanced WUE. However, field studies investigating long-term soil–biochar interactions that strongly conclude the impact of biochar under moisture stress conditions are lacking.

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Fátima Medina-Lara, Ramón Souza-Perera, Manuel Martínez-Estévez, Manuel O. Ramírez-Sucre, Ingrid M. Rodríguez-Buenfil and Ileana Echevarría Machado

The characteristics of the soil in the Peninsula of Yucatán confer unique organoleptic properties to the habanero pepper (Capsicum chinense Jacq.), and thus this entity possesses the denomination of origin of the species, making these chilis the most coveted, nationally and internationally. However, the extreme microtopographic variation distinguishing the Peninsula complicates the transfer of technologies and the successful establishment of agricultural practices. Maya farmers of the region identify the brown soils as preferable for the cultivation of this chili, although there is some controversy among the farmers regarding the best yields when the quality of the water used for irrigation is poor. No studies of the effect of soil type on this plant have been carried out. This work evaluated the impact of three types of soil of the Peninsula (red, brown, and black) on growth, fruit production, and nutrient content in soils and plants, during different phenological stages. The results indicate that the red and brown soils were the best for the growth and production of the fruit. In the black soil, it was possible to observe greater retention and accumulation of sodium applied in the water used for irrigation and in the macronutrients N, P, K, which may have led to a negative effect in the development of the fruit in these plants. Moreover, the plants growing in red and brown soils seem to make a more efficient use of the nutrients, presenting higher values of N, P, and K in their tissues in the flowering-fructification stage. These results are particularly useful in the realization of agricultural plans with a lower consumption of fertilizers, which allows an increase in yield, particularly if we take into account the enormous problems of saline intrusion worldwide and in this region.