The downwash flow field of the multi-rotor unmanned aerial vehicle (UAV), formed by propellers during operation, has a significant influence on the deposition, drift and distribution of droplets as well as the spray width of the UAV for plant protection. To study the general characteristics of the distribution of the downwash airflow and simulate the static wind field of multi-rotor UAVs in hovering state, a 3D full-size physical model of JF01-10 six-rotor plant protection UAV was constructed using SolidWorks. The entire flow field surrounding the UAV and the rotation flow fields around the six rotors were established in UG software. The physical model and flow fields were meshed using unstructured tetrahedral elements in ANSYS software. Finally, the downwash flow field of UAV was simulated. With an increased hovering height, the ground effect was reduced and the minimum current velocity increased initially and then decreased. In addition, the spatial proportion of the turbulence occupied decreased. Furthermore, the appropriate operational hovering height for the JF01-10 is considered to be 3 m. These results can be applied to six-rotor plant protection UAVs employed in pesticide spraying and spray width detection.

To solve the common problem of flumes flow-measurement accuracy without sacrificing water head, a new type of trapezoidal cutthroat flume to measure the discharge in terminal trapezoidal channels is presented. Using the computational fluid dynamic method, three-dimensional flow fields in trapezoidal cutthroat flumes were simulated using the RNG k-ε three-dimensional turbulence model along with the TruVOF technique. Simulations were performed for 12 working conditions, with discharges up to 0.075 m³·s⁻¹ to determine hydraulic performance. Experimental data for the trapezoidal cutthroat flume in terminal trapezoidal channel were also obtained to validate the simulation results. Velocity distribution of the flume obtained from simulation analyses were compared with observed results based on time-averaged flow field and comparison yielded a solid agreement between results from the two methods, with relative error below 10%. The results indicated that the Froude number and the longitudinal average velocity increased along the convergence section and decreased in the divergent section. In the upper throat, the Froude number was less than 0.5, which meets the water measurement requirement, and the critical flow appeared near the throat section. The maximum water head loss of the trapezoidal cutthroat flume was less than 9% of the total head, compared to the rectangular cutthroat flume, and head loss of trapezoidal cutthroat flume was significantly less. Regression models developed for upstream depth versus discharge under different working conditions were satisfactory, with a relative error of less than 2.06%, which meets the common requirements of flow measurement in irrigation areas. It was concluded that trapezoidal cutthroat flumes can improve flow-measurement accuracy without sacrificing water head.

To improve the accuracy of runoff forecasting, an uncertain multiple linear regression (UMLR) model is presented in this study. The proposed model avoids the transfer of random error generated in the independent variable to the dependent variable, as this affects prediction accuracy. On this basis, an inexact two-stage stochastic programming (ITSP) model is used for crop planting structure optimization (CPSO) with the inputs that are interval flow values under different probabilities obtained from the UMLR model. The developed system, in which the UMLR model for runoff forecasting and the ITSP model for crop planting structure optimization are integrated, is applied to a real case study. The aim of the developed system is to optimize crops planting area with limited available water resources base on the downstream runoff forecasting in order to obtain the maximum system benefit in the future. The solution obtained can demonstrate the feasibility and suitability of the developed system, and help decision makers to identify reasonable crop planting structure under multiple uncertainties.

Alternate partial root-zone irrigation (APRI) can improve water use efficiency in arid areas. However, the effectiveness and outcomes of different frequencies of APRI on water uptake capacity and physiological water use have not been reported. A two-year field experiment was conducted with two irrigation amounts (400 and 500 mm) and three irrigation methods (conventional irrigation, APRI with high and low frequencies). Root length density, stomatal conductance, photosynthetic rate, transpiration rate, leaf water use efficiency, midday stem and leaf water potentials were measured. The results show that in comparison with conventional irrigation, APRI with high frequency significantly increased root length density and decreased water potentials and stomatal conductance. No differences in the above indicators between the two APRI frequencies were detected. A significantly positive relationship between stomatal conductance and root length density was found under APRI. Overall, alternate partial root-zone irrigation with high frequency has a great potential to promote root growth, expand water uptake capacity and reduce unproductive water loss in the arid apple production area.

The objectives of this study were to investigate the effects of red and blue LEDs on in vitro growth and microtuberization of potato (Solanum tuberosum) single-node cuttings. Explants were incubated under 6 light treatments: 100% red LEDs (R), 75% red LEDs+ 25% blue LEDs (3RB), 50% red LEDs+ 50% blue LEDs (RB), 25% red LEDs+ 75% blue LEDs (R3B), 100% blue LEDs (B) and white LEDs (W). Most of the growth and physiological parameters were significantly higher in 3RB than W. Enhancement of leaf area and chlorophyll concentrations were obtained in B. Leaf stomata were elliptical with the lowest density in 3RB. However, those in W were round in shape, and those with the smallest size and the highest density were observed in R. Most of the characteristics of microtuberization were also improved in 3RB. The combined spectra of red and blue LEDs increased the number of large microtubers. The fresh weight of individual microtubers in R and W were increased, but not their number. These results suggest that, of the treatments assessed, 3RB is optimal for the in vitro growth of potato plantlets and the combination of red and blue LEDs is beneficial for microtuberization.

High concentrations of Cd can inhibit growth and reduce the activity of the photosynthetic apparatus in plants. In several plant species, aldo-keto reductases (AKRs) have been shown to enhance tolerance to various abiotic stresses by scavenging cytotoxic aldehydes; however, few AKRs have been reported to enhance Cd stress tolerance. In this study, the gene IbAKR was isolated from sweet potato. The relative expression levels of IbAKR increased significantly (approximately 3-fold) after exposure to 200 mmol·L⁻¹ CdCl₂ or 10 mmol·L⁻¹ H₂O₂. A subcellular localization assay showed that IbAKR is predominantly located in the nucleus and cytoplasm. IbAKR-overexpressing tobacco plants showed higher tolerance to Cd stress than wild-type (WT). Transgenic lines showed a significant ability to scavenge malondialdehyde (MDA) and methylglyoxal (MG). In addition, proline content and superoxide dismutase activity were significantly higher and H₂O₂ levels were significantly lower in the transgenic plants than in the WT. Quantitative real-time PCR analysis showed that the reactive oxygen species (ROS) scavenging genes encoding guaiacol peroxidase (GPX), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR) and peroxidase (POD) were significantly upregulated in transgenic plants compared to WT under Cd stress. These findings suggest that overexpressing IbAKR enhances tolerance to Cd stress via the scavenging of cytotoxic aldehydes and the activation of the ROS scavenging system.

Sweet potato, Ipomoea batatas, is a globally important food crop. The purple-fleshed sweet potato, rich in anthocyanins, has great potential for both nutritional and pharmaceutical uses. In this study, we characterized the root transcriptomes of the purple-fleshed sweet potato cv. Jingshu 6 and its mutant JS6-5 with high anthocyanin content by high-throughput RNA sequencing. A total of 22873364 and 27955097 high quality reads were obtained from Jingshu 6 and JS6-5, respectively, and assembled into 35592 unigenes. In all, we obtained 1566 differentially expressed genes (DEGs). Among them, 994 were upregulated and 572 were downregulated in JS6-5 compared to the expression in Jingshu 6. A total of 1436 DEGs were annotated, in which 847 DEGs had gene ontology (GO) terms and 329 DEGs were assigned to 84 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Most importantly, 23 differentially expressed genes and 24 transcription factors were identified as candidate genes involved in anthocyanin biosynthesis. In addition, 2349 SSRs were detected. This study not only provides the candidate genes but also provides insights into the molecular mechanism of anthocyanin biosynthesis in sweet potato.

Potassium is an essential nutrient for plant growth and productivity of crops. K⁺ transporters are important for K⁺ uptake and transport in plants. However, information on the function of K⁺ transporters and K⁺ channels in cotton is limited. The KT/KUP/HAK protein family is essential for a variety of physiological processes in plants, including nutrient acquisition and regulation of development. This study, identified a K⁺ transporter gene, GhKT2, expressed in the roots of cotton (Gossypium hirsutum) cv. Liaomian17. The deduced transcript of GhKT2 is highly homologous to Cluster II of KUP/HAK/KT K⁺ transporters and is predicted to contain 11 transmembrane domains. GhKT2 has been localized to the plasma membrane, and its transcripts were detected in roots, stems, leaves and shoot apices of cotton seedlings. Consistently, b-glucuronidase (GUS) expression driven by the GhKT2 promoter could be detected in roots, mesophyll cells, and leaf veins in transgenic Arabidopsis. In addition, the expression of GhKT2 was induced by low K⁺ stress in cotton roots and pGhKT2::GUS-transgenic Arabidopsis seedlings. The GhKT2-overexpression Arabidopsis lines plants were larger and showed greater K⁺ accumulation than the wild type (WT) regardless of K⁺ concentration supplied. The net K⁺ influx rate, measured by the noninvasive micro-test technique, in root meristem zone of GhKT2-transgenic Arabidopsis lines was significantly greater than that of WT. Taken together, this evidence indicates that GhKT2 may participate in K⁺ acquisition from low or high external K⁺, as well as K⁺ transport and distribution in plants.

Plants have developed sophisticated systems to cope with herbivore challenge, including morphological barriers and secondary metabolites to reduce damage. In this study, 550 Gossypium genotypes were evaluated for whitefly (Bemisia tabaci) resistance in five experiments including two in the field and three in the greenhouse, with 23 resistant and 19 susceptible genotypes selected. Whitefly-resistance index determination showed that a leaf having a high density of hairs had resistance to whitfly egg/nymph production. Longer leaf hairs were also important for resistance. This study revealed that okra shaped leaves reduced adult whitefly oviposition preference, while glabrous leaves and high hair density helped not only in the reduction of the adults but also decreased oviposition preference. Gossypol was also observed to be involved in the reduction of adult whitefly development and/or survival.

Pre-harvest sprouting in wheat is the germination of seeds within the spikes when rains occur after or during grain ripening, which occurs commonly in the barani tract of Pakistan. Therefore, 10 cultivars and five advanced lines of spring bread wheat were evaluated for pre-harvest sprouting resistance. After natural rainfall, seeds were immediately collected from the wet spikes and tested for germinating ability. Three different germination tests were applied to hand-threshed seed: (1) spikes threshed on the day of sampling and germination tested immediately, (2) spikes threshed on the day of sampling and germination tested 1 week later, and (3) spikes threshed 1 week after sampling and germination test immediately after threshing. Seeds and spikes kept for 1 week were place on blotting paper at room temperature. Cultivars BARS-09, 09FJ17, Doukkala-12, NARC-09 and Ouassou-20 exhibited higher sprouting resistance while other genotypes were susceptible to pre-harvest sprouting in each of the three tests. A diallel crossing was conducted with six susceptible and two resistant genotypes to assess the genetic behavior of pre-harvest sprouting resistance. The combining ability (CA) demonstrated a higher proportion of additive genetic effects for sprouting resistance, because of higher variance of general and specific CA for both parameters under study. Doukkala-12 and BARS-09 showed increased pre-harvest sprouting resistance in their F₁ descendants.

Four kinds of antifungal compounds from an extract of Paenibacillus polymyxa A21 with molecular masses of 883.56, 897.59, 947.55, and 961.58 Da were characterized as the members of fusaricidin-type of antibiotics according to LC-MS analysis. Fusaricidins isolated from culture filtrate displayed high antagonistic activity against several plant fungal pathogens, especially Botrytis cinerea, the causal agent of gray mold. The fusaricidins biosynthetic gene cluster (BGC) from A21 was cloned by PCR and comparative cluster analysis revealed that gene fusTE, the 3′ boundary of the fusaricidin BGC in strain PKB1, was not present in fusaricidin BGC of A21, indicating that fusTE is not necessary for fusaricidin synthesis. Fusaricidin extract from A21 significantly reduced gray mold disease incidence and severity on tomato. The mRNA levels for three patho-genesis-related proteins (PRs) revealed that treatment of tomato leaves with fusaricidin extract induced the expression of PR genes to different levels, suggesting that one reason for the reduction of gray mold infection by fusaricidin is induction of PR proteins, which lead to increased resistance to pathogens. This is the first report of the application of fusaricidins to control tomato gray mold and the comparative cluster analysis provides important molecular basis for research on fusaricidin biosynthesis.

This study reports a strain of Trichoderma harzianum CCTCC-SBW0162 with potential to enhance biocontrol activity against gray mold pathogen, Botrytis cinerea, and with a pivotal role in tomato (Solanum esculentum) plant growth enhancement. A total of 254 Trichoderma isolates were screened by in vitro antagonistic assay. Of these, 10 were selected for greenhouse experiments based on their greater inhibition of B. cinerea. The in vitro antagonistic assay and greenhouse experiments indicated that T. harzianum CCTCC-SBW0162 gave the highest inhibition rate (90.6%) and disease reduction (80.7%). Also, to study the possible mechanism associated with antifungal activity of CCTCC-SBW0162 against B. cinerea, molecular docking was used to assess the interactions between CCTCC-SBW0162-derived metabolites, and pathogencity and virulence related proteins of B. cinerea. The molecular docking results indicated that the combination of harzianopyridone, harzianolide and anthraquinone C derived from CCTCC-SBW0162 could synergistically improve antifungal activity against B. cinerea through the inhibition/modification of pathogenicity and virulence related proteins. However, this computerized modeling work emphasized the need for further study in the laboratory to confirm the effect T. harzianum-derived metabolites against the proteins of B. cinerea and their interactions.

Greenhouse gas emissions due to biological degradation processes of animal wastes are significant sources of air pollution from agricultural areas. The major environmental controls on these microbe-induced gas fluxes are temperature and moisture content. The objective of this study was to model the effects of temperature and moisture content on emissions of CO₂ and CH₄ during the ambient drying process of dairy manure under controlled conditions. Gas emissions were continuously recorded over 15 d with paired fully automated closed dynamic chambers coupled with a Fourier Transformed Infrared gas analyzer. Water content and temperature were measured and monitored with capacitance sensors. In addition, on days 0, 3, 6, 9, 12 and 15, pH, moisture content, dissolved organic carbon and total carbon (TC) were determined. An empirical model derived from the Arrhenius equation confirmed high dependency of carbon emissions on temperature and moisture content. Results indicate that for the investigated dairy manure, 6.83% of TC was lost in the form of CO₂ and 0.047% of TC was emitted as CH₄. Neglecting the effect of temperature, the moisture contents associated with maximum gas emissions were estimated as 0.75 and 0.79 g·g⁻¹ for CO₂ and CH₄, respectively.