Growth Period Research Articles

Influence of Selenium on the Yield and Content of the Amino Acid Composition of Spring Wheat Grain under Optimal Conditions of Water Supply and during Drought

In model experiments in soil culture, the effect of various methods of applying sodium selenite on the formation of yield and amino acid composition of grain varieties of spring wheat Zlata and Ester, depending on water supply conditions, was studied. Sodium selenite was introduced by pre-sowing seed treatment and leaf treatment of vegetative plants. The study simulated optimal water supply conditions and soil moisture deficiency during the critical period of plant growth. The role of selenium in the regulation of the production process and the formation of the amino acid composition of spring wheat grain was studied. It was found that the production process of wheat plants, both under optimal water supply and in drought conditions, depended on the method of application of selenium and the varietal characteristics of spring wheat. The results allowed us to assume that selenium activated the attenuating ability of the ear by enhancing its acceptor properties. Under these conditions, the grains were better provided with assimilates. this made it possible to form the maximum possible yield of wheat grain. In conditions of drought, during leaf treatment of plants with sodium selenite, favorable conditions were created for the formation of reproductive organs of wheat, which stimulated the restoration of the processes of assimilate outflow from the vegetative mass into the forming grains. This made it possible to influence production processes and reduce the depression of wheat crop formation. The use of selenium revealed an increase in the total content of key amino acids, which had a significant effect on the antioxidant status of plants and contributed to the realization of their adaptive potential. The positive effect of selenium on the content of a number of amino acids, including on the assimilation of methionine, was revealed, which was probably due to the synthesis of selenomethionine, since the ways of their formation are similar and it is not possible to separate them. The greatest effect of selenium was observed in the cultivation of wheat of the Zlata variety compared with wheat of the Ester variety, which was determined by varietal differences inherent genetically and the unequal protein content in the grain.

Decoding stomatal characteristics regulating water use efficiency at leaf and plant scales in rice genotypes.

Stomatal traits in rice genotypes affect water use efficiency. Low-frequency small-size stomata correlate with whole plant efficiency, while low-frequency large-size stomata show intrinsic efficiency and responsiveness to vapour pressure deficit. Leaf surface and the patterning of the epidermal layer play a vital role in determining plant growth. While the surface helps in determining radiation interception, epidermal pattern of stomatal factors strongly regulate gas exchange and water use efficiency (WUE). This study focuses on identifying distinct stomatal traits among rice genotypes to comprehend their influence on WUE. Stomatal frequency ranged from 353 to 687 per mm2 and the size varied between 128.31 and 339.01 μm2 among 150 rice germplasm with significant variability in abaxial and adaxial surfaces. The cumulative water transpired and WUE determined at the outdoor phenomics platform, over the entire crop growth period as well as during specific hours of a 24h-day did not correlate with stomatal frequency nor size. However, genotypes with low-frequency and large-size stomata recorded higher intrinsic water use efficiency (67.04μmol CO2 mol-1 H2O) and showed a quicker response to varying vapour pressure deficit that diurnally ranged between 0.03 and 2.17kPa. The study demonstrated the role of stomatal factors in determining physiological subcomponents of WUE both at single leaf and whole plant levels. Differential expression patterns of stomatal regulatory genes among the contrasting groups explained variations in the epidermal patterning. Increased expression of ERECTA, TMM and YODA genes appear to contribute to decreased stomatal frequency in low stomatal frequency genotypes. These findings underscore the significance of stomatal traits in breeding programs and strongly support the importance of these genes that govern variability in stomatal architecture in future crop improvement programs.

Estimation of changes in carbon sequestration and its economic value with various stand density and rotation age of Pinus massoniana plantations in China

Plantations actively participate in the global carbon cycle and play a significant role in mitigating global climate change. However, the influence of forest management strategies, especially planting density management, on the biomass carbon storage and production value of plantations for ensuring carbon sink benefits is still unclear. In this study, we estimated the carbon sequestration and economic value of Pinus massoniana plantations with various stand densities and rotation ages using a growth model method. The results revealed that with increasing stand age, low-density plantations at 2000 trees·ha−1 (358.80 m3·ha−1), as well as high-density plantations at 4500 trees·ha−1 (359.10 m3·ha−1), exhibited nearly identical standing volumes, which indicated that reduced inter-tree competition intensity favors the growth of larger trees during later stages of development. Furthermore, an increase in planting density led to a decrease in the average carbon sequestration rate, carbon sink, and number of trees during the rapid growth period, indicating that broader spacing between trees is favorable for biomass carbon accumulation. Further, extending the rotation period from 15 to 20 years or 25 years and reducing the optimal planting density from 3000 to 2000 trees·ha−1 increased the overall benefits of combined timber and carbon sink income by 2.14 and 3.13 times, respectively. The results highlighted that optimizing the planting density positively impacts the timber productivity and carbon sink storage of Pinus massoniana plantations and boosts the expected profits of forest managers. Thus, future afforestation initiatives must consider stand age and planting density management to shift from a scale-speed pattern to a quality-benefit design.

YOLO-Granada: a lightweight attentioned Yolo for pomegranates fruit detection

Pomegranate is an important fruit crop that is usually managed manually through experience. Intelligent management systems for pomegranate orchards can improve yields and address labor shortages. Fast and accurate detection of pomegranates is one of the key technologies of this management system, crucial for yield and scientific management. Currently, most solutions use deep learning to achieve pomegranate detection, but deep learning is not effective in detecting small targets and large parameters, and the computation speed is slow; therefore, there is room for improving the pomegranate detection task. Based on the improved You Only Look Once version 5 (YOLOv5) algorithm, a lightweight pomegranate growth period detection algorithm YOLO-Granada is proposed. A lightweight ShuffleNetv2 network is used as the backbone to extract pomegranate features. Using grouped convolution reduces the computational effort of ordinary convolution, and using channel shuffle increases the interaction between different channels. In addition, the attention mechanism can help the neural network suppress less significant features in the channels or space, and the Convolutional Block Attention Module attention mechanism can improve the effect of attention and optimize the object detection accuracy by using the contribution factor of weights. The average accuracy of the improved network reaches 0.922. It is only less than 1% lower than the original YOLOv5s model (0.929) but brings a speed increase and a compression of the model size. and the detection speed is 17.3% faster than the original network. The parameters, floating-point operations, and model size of this network are compressed to 54.7%, 51.3%, and 56.3% of the original network, respectively. In addition, the algorithm detects 8.66 images per second, achieving real-time results. In this study, the Nihui convolutional neural network framework was further utilized to develop an Android-based application for real-time pomegranate detection. The method provides a more accurate and lightweight solution for intelligent management devices in pomegranate orchards, which can provide a reference for the design of neural networks in agricultural applications.

Rice Growth and Leaf Physiology in Response to Four Levels of Continuous Drought Stress in Southern China

Exploring the growth and physiological response mechanisms of rice under continuous drought stress circumstances can provide a significant scientific foundation and technological assistance for meeting drought difficulties, improving drought resistance and rice (Oryza sativa L.) output, and ensuring food security. In this study, a rice field experiment was conducted under a rain shelter with five different treatments set up: P1 (drought stress from tillering stage), P2 (drought stress from jointing–booting stage), P3 (drought stress from heading–flowering stage), P4 (drought stress from grain filling stage), and CK (adequate water management throughout the growth stage). Continuous drought stress from different growth stages with four levels (mild, medium, moderate, and severe). The results showed that the effects of different drought stress treatments on rice growth varied significantly. Compared with the CK treatment, plant height was reduced by 12.10%, 8.14%, 3.83%, and 1.06% in the P1, P2, P3, and P4 treatments, respectively, and the number of tillers was reduced by 23.83%, 18.91%, 13.47%, and 8.68%, respectively. With the increase in drought stress levels, SPAD values and Rubisco activity of rice leaf continued to decrease; SOD activity showed a decreasing trend, but the decreasing trend of POD and CAT activities was not significant, while MDA content showed an increasing trend. For yield components, continuous drought stress significantly reduced spike length of rice by an average of 3.5%, effective number of spikes by 18.9%, thousand grain weight by 3.7%, grain number per spike by 11.6%, and fruiting rate by 1.8%, respectively, compared to CK treatments during the growth period. In general, continuous drought stress during the early growth period affected the effective spike number and the grain number per spike. Continuous drought stress after the grain filling stage had the least effect on yield (17.62% of yield reduction), and water use efficiency (1.76 kg m−3) was much higher than other treatments. These researchers’ findings provide insight into how rice physiology and growth react to continuous drought stress, which is significant for agricultural operations.

Quantification Assessment of Winter Wheat Sensitivity under Different Drought Scenarios during Growth

To effectively reveal the disaster-causing mechanism between water stress and yield loss under different drought combinations during multiple growth periods of winter wheat, based on biennial wheat drought experiments, a crop growth analysis method was used to quantitatively identify and assess wheat yield loss sensitivity. The results showed that there was a significant negative correlation between the total dry matter relative growth rate (RGR) of wheat and the daily average degree of drought stress. The average determination coefficients of logarithmic fitting for 2017 and 2018 were 0.7935 and 0.7683, respectively. Wheat dry matter accumulation differed under the different drought combination scenarios. The yield loss sensitivity response relationship between the decrease in the RGR of wheat dry matter (relative to no drought stress) and the daily average degree of drought stress could be quantitatively identified by an S-shaped curve, and the 2017 and 2018 average coefficients of determination R2 were 0.859 and 0.849, respectively. Mild drought stress at the tillering stage stimulates adaptability and has little effect on yield. The soil water content (SWC) can be controlled to 65–75% of the field water holding capacity; the SWC at the jointing and booting stage can be controlled to be higher than the field water holding capacity of 55%. The SWC was maintained at a level higher than 75% of the field water holding capacity during the heading and flowering stages and the grain-filling and milky stages to achieve a harmonization of yields and water savings. In addition, during the production process, continuous severe drought during the jointing and booting stage and the heading and flowering stage should be avoided. This study elucidates the response relationship between drought intensity and drought-induced losses from the perspective of physical genesis, provides effective irrigation guidance for regional wheat planting, lays the foundation for the construction of quantitative agricultural drought loss risk curves, and provides technical support for predicting the trend of yield losses in wheat under different drought stresses.

Effects of a newly developed toe exercise program combined with the intrinsic and extrinsic muscle trainings on toe function: a case series.

Foot and toe function is important for not only sports performance but also preventing and treating musculoskeletal disorders. Although strengthening training specific to intrinsic and extrinsic muscles has been recommended, insufficient information is available in toe exercises in their variation and evidences compared to shoulder or lumbopelvic training strategies. The aim was to examine the effects of a newly developed foot muscle exercise program on toe function in individuals during the growth period. This is a single-group, pretest-posttest case series. Both feet of seven male patients in their growth period with sports-related overuse injuries of the lower extremities (mean age, 11 years) underwent a four-week strength exercise of the toes, consisting of intrinsic and extrinsic muscle-targeted exercises. Main outcome measures were as follows: 1) flexion force of each toe; 2) compression force of each toe; 3) dexterity of the toes evaluated using the "rock-paper-scissors test"; 4) toe loading during single-leg squat exercise. An F-scan system was used to measure 2 and 4. All patients performed the program appropriately and completed the program for four weeks. Significant improvements were observed in the outcome measures of 1 to 4. The combined exercise program for the intrinsic and extrinsic muscles of the foot effectively improved toe strength, dexterity, and loading during dynamic motion and could be easily performed in individuals during the growth period.

Spatiotemporal patterns of leaf nutrients of wild apples in a wild fruit forest plot in the Ili Valley, China

Malus sieversii, commonly known as wild apples, represents a Tertiary relict plant species and serves as the progenitor of globally cultivated apple varieties. Unfortunately, wild apple populations are facing significant degradation in localized areas due to a myriad of factors. To gain a comprehensive understanding of the nutrient status and spatiotemporal variations of M. sieversii, green leaves were collected in May and July, and the fallen leaves were collected in October. The concentrations of leaf nitrogen (N), phosphorus (P), and potassium (K) were measured, and the stoichiometric ratios as well as nutrient resorption efficiencies were calculated. The study also explored the relative contributions of soil, topographic, and biotic factors to the variation in nutrient traits. The results indicate that as the growing period progressed, the concentrations of N and P in the leaves significantly decreased (P < 0.05), and the concentration of K in October was significantly lower than in May and July. Throughout plant growth, leaf N–P and N–K exhibited hyperallometric relationships, while P–K showed an isometric relationship. Resorption efficiency followed the order of N < P < K (P < 0.05), with all three ratios being less than 1; this indicates that the order of nutrient limitation is K > P > N. The resorption efficiencies were mainly regulated by nutrient concentrations in fallen leaves. A robust spatial dependence was observed in leaf nutrient concentrations during all periods (70.1–97.9% for structural variation), highlighting that structural variation, rather than random factors, dominated the spatial variation. Nutrient resorption efficiencies (NRE, PRE, and KRE) displayed moderate structural variation (30.2–66.8%). The spatial patterns of nutrient traits varied across growth periods, indicating they are influenced by multifactorial elements (in which, soil property showed the highest influence). In conclusion, wild apples manifested differentiated spatiotemporal variability and influencing factors across various leaf nutrient traits. These results provide crucial insights into the spatiotemporal patterns and influencing factors of leaf nutrient traits of M. sieversii at the permanent plot scale for the first time. This work is of great significance for the ecosystem restoration and sustainable management of degrading wild fruit forests.

Incorrectly healed supracondylar humerus fracture : That will grow out later on?!

The supracondylar humerus fracture is the most frequent fracture of the elbow region during the growth period. The peak age is around 5years. Extension fractures predominate. The clinical diagnostics are supplemented by X‑ray images in two projections. Growth-associated spontaneous corrections of posttraumatic deformities rarely occur. The goal of treatment is therefore the active transformation of every displaced fracture into a nondisplaced stably fixed fracture.If this is not successful, the consequences of healing in amalalignment can be, e.g., restriction of elbow flexion due to remaining antecurvation or cubitus varus. Combinations are often present. The causes include technical problems with reduction and retention but also misjudgement of the X‑ray findings, ignorance of the growth prognosis or inadequate verification of whether the treatment goal has been achieved.Unsatisfactory treatment results should be corrected as early as possible. This can be done primarily before bony healing is completed or secondarily as acorrective osteotomy at any later point in time. The earlier the correction of the malalignment is performed, the greater the chances of a complete restoration to the original condition. Depending on the type and extent of the deformity various techniques for corrective osteotomy are suggested in the literature.

Distribution of phthalate esters and their metabolites in peanut plant during the entire growth period and their dietary risk assessment of peanuts in China

AbstractTo understand the remediation potential of peanut plants to phthalate esters (PAEs) contamination, the absorption and accumulation patterns of dibutyl phthalate (DBP), bis (2‐ethylhexyl) phthalate (DEHP), and diisononyl ortho‐phthalate (DINP), as well as their metabolites—monoalkyl phthalate esters (MPEs), monobutyl phthalate (MBP), monoethylhexyl phthalate (MEHP), and monoisononyl phthalate (MINP), were examined in peanut plant during the entire growth period. It was found that the amounts of DBP and MBP in peanut plants correlated positively, when the DBP content is high, the MBP content is also high, as well as DEHP and MEHP. Additionally, the root contained the highest overall concentrations of DBP, DEHP, DINP, MBP, and MEHP over the course of the growth cycle. To evaluate PAEs contamination and dietary risk of peanuts in China, 18 PAEs and seven MPEs in 490 peanut samples collected from 17 provinces of China were detected by UPLC‐MS/MS, the detection rate of 18 selected PAE in peanut was 100%. The dietary risk assessment suggested that the general population and high consuming population are not at risk of non‐carcinogenic from the PAEs and MPEs found in peanuts of China. There is no need for the general consumption group to take any precautions against the carcinogenic risk of DEHP, and the high consumption group's carcinogenic risk is also within an acceptable range.

Policy evaluation and performance assessment for sustainable urbanization: a study of selected city corporations in Bangladesh

Bangladesh is going through an unprecedented period of urban growth, and its cities are having to deal with rising service, housing, and infrastructural needs. It is critical to comprehend how urban government promotes sustainable development as the nation struggles with the intricacies of urbanization. This study aims to investigate how urban governance impacts sustainable urbanization at the city corporation level in Bangladesh, focusing on Goal 11 of the Sustainable Development Agenda, which is “sustainable cities and communities.” The study selected Rajshahi and Gazipur City Corporations as case studies and employed Principal Component Analysis (PCA) and descriptive statistics methods to gather data from primary and secondary sources. The findings of the study reveal gaps in urban governance, highlighting inconsistencies between the expectations of stakeholders and the reality on the ground. Stakeholders express high expectations for housing access, infrastructure development, disaster management, transportation, and environmental sustainability, but the current state falls short in several areas. Further, the study proposes several recommendations to enhance urban governance, including fostering participatory approaches, ensuring sufficient budget allocation for infrastructure development, addressing housing challenges, enhancing women’s safety in transportation, and strengthening disaster management systems.

Success of introduction of species of the genus &lt;i&gt;Cotoneaster&lt;/i&gt; Medik. in the Komi Republic

Among the woody plants preserved and studied in the arboretum of the Botanical Garden of the Institute of Biology of the Komi Scientific Center of the Ural Branch of the Russian Academy of Sciences for nine years (2013–2021) include representatives of the polymorphic genus Cotoneaster of different geographical origins. As a result of generalization and analysis of data on biomorphology, characteristics of the generative period, dynamics of seasonal growth and development, winter hardiness of plants of species of the genus Cotoneaster introduced in the North, based on an assessment of the main indicators of viability, the studied plants were divided into groups of prospects for cultivation in the northern region. Plants of Eurasian origin C. melanocarpus and C. integerrimus, which undergo a full cycle of seasonal development, are characterized by high winter hardiness, form full-fledged seeds and retain their vital form under introduction conditions, are classified in Group I as quite promising. The East Asian species C. dammeri, C. horizontalis are assigned to the II group of promising plants and C. ascendens to the III group of unpromising plants. These introduced species were characterized by an extended period of growth and development, late completion of the growing season, low winter hardiness, but good shoot recovery ability after winter damage. C. bullatus turned out to be an unpromising species (group V) with low winter hardiness, and therefore the impossibility of transition to the generative period of development. Additional study of this decorative species with the involvement of other specimens is necessary. Based on the data obtained, species such as C. melanocarpus, C. integerrimus, C. dammeri and C. horizontalis can be recommended for cultivation and use in landscaping in some areas of the Komi Republic.

Winter Targeted Observing Periods during the Year of Polar Prediction in the Southern Hemisphere (YOPP-SH)

Abstract The Year of Polar Prediction in the Southern Hemisphere (YOPP-SH) held seven Targeted Observing Periods (TOPs) during the 2022 austral winter to enhance atmospheric predictability over the Southern Ocean and Antarctica. The TOPs of 5-10 days duration each featured the release of additional radiosonde balloons, more than doubling the routine sounding program at the 24 participating stations run by 14 nations, together with process-oriented observations at selected sites. These extra sounding data are evaluated for their impact on forecast skill via data denial experiments with the goal of refining the observing system to improve numerical weather prediction for winter conditions. Extensive observations focusing on clouds and precipitation primarily during atmospheric river (AR) events are being applied to refine model microphysical parameterizations for the ubiquitous mixed phase clouds that frequently impact coastal Antarctica. Process studies are being facilitated by high time resolution series of observations and forecast model output via the YOPP Model Intercomparison and Improvement Project (YOPPsiteMIIP). Parallel investigations are broadening the scope and impact of the YOPP-SH winter TOPs. Studies of the Antarctic tourist industry’s use of weather services show the scope for much greater awareness of the availability of forecast products and the skill they exhibit. The SIPN South analysis of predictions of the sea ice growth period reveals that the forecast skill is superior to the sea ice retreat phase.

Effect of casein bioactive peptides on performance, nutrient digestibility, enzyme activity and intestinal microbial population in broiler chickens.

This experiment was carried out to investigate the effect of bioactive peptides derived from casein on performance, nutrient digestibility, enzyme activity and intestinal microbial population in broiler chickens. In this study, 350 1-day-old male Ross 308 broiler chicks were distributed among 35 pens in a completely randomized design with seven treatments, five replicates and 10 chicks in each replicate. The experimental treatments included: basal diet without any additives (control), basal diet + Avilamycin antibiotic, basal diet + 200, 400, 600, 800 and 1000 mg of peptides per kg of diet. Results showed no significant effects of the experimental treatments on weight gain and feed conversion ratio during the starter period, but there was a significant improvement in weight gain in grower, finisher and whole periods in chicks fed with diet containing 1000 mg/kg peptides (p < 0.05). Adding peptides improved intestinal morphology (in duodenum and ileum) (p < 0.05). Supplementation of casein peptides significantly reduced thiobarbituric acid reactive substances concentration in breast and thigh meat. The activity of amylase, lipase and protease enzymes improved in treatments containing 800 and 1000 mg peptides in comparison to the control treatment. The use of casein-peptides increased intestinal Lactobacillus and decreased Coliform populations.

Effect of nano-urea and irrigation regimes on growth parameters of wheat (Triticum aestivum L.)

Wheat (Triticum aestivum L.) is a crucial cereal crop globally, serving as a staple food for a vast population. Its productivity faces challenges such as nutrient imbalance and terminal heat stress exacerbated by climate change, particularly in regions like the North-Eastern Plain Zone of India. To address these issues, a study was conducted during the rabi season of 2021–2022 in Jharkhand, India, aiming to examine the impacts of irrigation regimes and nano-urea-based nitrogen management practices on wheat. Employing a split-plot design with three replications, the experiment assessed three irrigation regimes and five nitrogen management practices. Results revealed that irrigation regimes registered non-significant effects on crop growth parameters like plant height, LAI (leaf area index), root dry weight, flag leaf area and tillers/m2 , which might be due to frequent rain up to the flowering stage during the crop growth period. Higher levels of nitrogen in commercial urea significantly increased plant height, LAI, flag leaf area, recovered root dry weight and dry matter accumulation. However, nano-urea spray at 45 DAS helped crop plants positively to increase all growth parameters more compared to nano-urea spray at 60 DAS. All growth attributes with 50% RDN+2-nano-urea spray were statistically at par with 50% RDN+1 nano-urea spray up to 40 DAS, but after the flowering stage, it was statistically similar with 100% RDN. The maximum tillers/m2 was found under 100% RDN, followed by 75% RDN+ one nano-urea spray and 50% RDN+2 nano-urea spray. Thus, 3- irrigations at CRI, flowering and milk stage and 100% RDN (120 kg N/ha) were found sufficient for enhancing the growth parameters of wheat.

Concurrent drought threatens wheat and maize production and will widen crop yield gaps in the future

CONTEXTDrought poses a significant threat to global crop production. As the global community grapples with the escalating challenges of climate change, understanding the multifaceted impacts of concurrent drought on food security becomes imperative. OBJECTIVEThis study delved into the response of wheat and maize, key staples in the global food system, to different types of drought, with a particular focus on the yield gaps resulting from concurrent meteorological and agricultural drought. METHODSThe DSSAT-CERES model was adopted to simulate phenophase, rain-fed, and potential yields of maize and wheat in China from 1962 to 2100. Meteorological (Non-stationary Standard Precipitation Evapotranspiration Index, NSPEI) and agricultural (Standard Soil Moisture Index, SSMI) drought indices were calculated from crop seeding to maturity stages. We employed bivariate and multiple cross-wavelet as well as vine Copula to qualitatively and quantitatively analyze the response of yield gaps to different drought types. Finally, we determined the relative dependence weights of maize and wheat on NSPEI and SSMI by least squares regression. RESULTS AND CONCLUSIONSSpanning from 2022 to 2100, a trend of shortened growth periods for these crops were detected, accompanied by increasingly drier conditions. These situations exacerbated the crops' vulnerability to concurrent drought, leading to considerable yield reductions. Our projections indicated that future yield gaps due to concurrent drought could be, on average, 2–30% higher than those caused by single-type drought. Concurrent drought affected wheat (5–50%) more severely than maize (0–35%). Western regions would be more affected than the Eastern regions. Under the SSP (Shared socioeconomic pathway) 5-8.5 scenario in 2022–2100, all four crops would have higher dependence weights on SSMI (51–99%) than NSPEI (26–59%), emphasizing the critical role of soil moisture in agricultural drought monitoring and yield loss alleviation. SIGNIFICANCEOur findings highlight the urgent need for integrated drought management strategies that address the compounded risks of concurrent drought, thereby contributing to the resilience of agricultural systems and global food security in a changing climate. Our research proposes to consider the relative weights of meteorological and agricultural drought in the future development of composite drought monitoring indicators for addressing food drought risk under climate change.

Increasing dissolved oxygen concentration of irrigation water is beneficial to nitrogen uptake of cotton under mulched drip irrigation

ContextEnhancing crop nitrogen absorption is crucial for improving nitrogen fertilizer utilization efficiency. Soil oxygen conditions play a vital role in influencing crop nutrient uptake. However, the impact of dissolved oxygen concentration in irrigation water on cotton’s nitrogen absorption remains unknow under mulched drip irrigation conditions. RESEARCH QUESTION: This study aimed to investigate whether the dissolved oxygen concentration in irrigation water affects cotton’s nitrogen uptake. METHODS: Urea was utilized as the nitrogen fertilizer, and 5 dissolved oxygen concentration of irrigation water were set in the experiment by adding sodium percarbonate (CK: 3.9 mg L−1, CO1: 9.2 mg L−1, CO2: 13.3 mg L−1, CO3: 17.3 mg L−1, CO4: 25.5 mg L−1). RESULTS: The results showed that increasing the dissolved oxygen concentration in irrigation water could increase the soil urease activity and bacterial operational taxonomic units (OTU), which may be beneficial to the urea decomposition and nitrogen cycling function. Towards the end of the cotton growth period, oxygenation irrigation led to an increase in nitrate nitrogen and ammonium nitrogen content in the soil. The average nitrate nitrogen content in the 0–60 cm soil layer of CO1, CO2, CO3 and CO4 increased by 12.4 %, 14.7 %, 15.9 % and 17.3 % respectively compared with CK. Similarly, the average ammonium nitrogen content of CO1, CO2, CO3 and CO4 in the 0–40 cm soil layer increased by 8.9 %, 11.7 %, 12.0 % and 11.6 % respectively compared with CK. Increasing the dissolved oxygen concentration in irrigation water resulted in elevated dry matter accumulation in cotton. The total dry matter of CO1, CO2, CO3 and CO4 increased by 9.5 %, 12.6 %, 14.6 % and 16.8 % respectively compared with CK. Additionally, the nitrogen concentration in each cotton organ also exhibited an increase. The total nitrogen accumulation of CO1, CO2, CO3 and CO4 increased by 26.1 %, 36.2 %, 48.2 % and 53.1 % respectively compared with CK. Furthermore, increasing the dissolved oxygen concentration in irrigation water also facilitated nitrogen migration to cotton bolls (boll shell + seed + fiber). The cotton boll nitrogen accumulation of CO1, CO2, CO3 and CO4 increased by 1.8 %, 3.4 %, 4.2 % and 4.2 % (absolute value) compared with CK (reached significant level). Finally, the lint yield and fiber quality parameters (micronaire, fiber elongation, fiber breaking strength) exhibited further improvement with the increase in dissolved oxygen concentration in irrigation water. CONCLUSIONS: Increasing the dissolved oxygen concentration in irrigation water promotes nitrogen absorption in cotton, facilitates nitrogen accumulation in cotton bolls, and enhances nitrogen fertilizer utilization efficiency. Moreover, it positively impacts cotton lint yield and fiber quality.

Effects of Drip Irrigation Flow Rate and Layout Designs on Soil Salt Leaching and Cotton Growth under Limited Irrigation

Optimal drip irrigation management in shallow groundwater areas needs to clarify the effects of flow rate and layout designs on the soil moisture, salt distribution, cotton root length density, plant height, leaf area, and yield. In this study, a one-year field experiment was conducted from April to October 2018 in the fifth company of the 16th Regiment in Alar City, Xinjiang, to investigate the effects of various drip flow rates and layout designs of cotton growth. Two drip flow rates (2.8 and 5.6 L·h−1) and two layout designs (one film, two drip tapes, and six rows; one film, three drip tapes, and six rows) were applied to explore the optimal combination, resulting in a total of four treatments that were irrigated three times in the whole growth period. Soil moisture, salt distribution, cotton root length density, plant height, and leaf area were measured. The main results were as follows: (1) Under the same layout designs, the soil moisture content was higher and the soil salinity was lower when the drip flow rate was 5.6 L·h−1, and the cotton root length density, plant height, leaf area, and yield were significantly higher than that of 2.8 L·h−1. (2) Under the same drip flow rate, the soil desalination rate, cotton growth indexes, and yield under the three-tapes treatment were significantly higher than the values of the two-tapes treatment. The actual yield of treatment D was 21.56%, 19.23%, and 11.71% higher than that of treatments A, B, and C, respectively. (3) The crop evapotranspiration of cotton during the two irrigation cycles showed an increasing trend, and the groundwater contribution showed a smaller and then increasing trend. Overall, the combination of three tapes and a drip flow rate of 5.6 L·h−1 had the highest cotton yield and net income, which were 6211.36 kg·hm−2 and 4820.21 kg·hm−2 for the theoretical and actual yields. The results of this study can provide a reference for the management of limited irrigation leaching soil salinity and cotton cultivation in shallow groundwater areas.

High STI burden among a cohort of adolescents aged 12-19 years in a youth-friendly clinic in South Africa.

Adolescents face a higher risk for HIV, STIs, and unintended pregnancy than any other age group in sub-Saharan Africa, and have unique health care needs as they navigate this period of growth and developmental milestones. We conducted the Youth Friendly Services study among adolescents in Rustenburg, South Africa to address some of these concerns. Participants aged 12-19 were followed quarterly for 12 months, asked at baseline about demographics, their sexual behavior, and tested for HIV, STIs, and pregnancy (girls). Report of sexual activity was not a requirement for enrollment. Assent and parental consent were obtained for participants under 18. Some follow up visits fell during COVID-mandated shutdowns, and we worked with participants to reschedule and extend follow up as appropriate. Here we present data on reported behaviors, participant attrition, risk of HIV, other STI, and pregnancy. From May 2018 to August 2019, we enrolled 223 HIV-negative, non-pregnant adolescents (64% girls). The median age was 17 (IQR: 14-18). Among the 119 (53%) participants who reported being sexually active at baseline, the median age at first sex was 16 years (IQR: 15-17). During follow-up, an additional 16 (7%) participants reported having their first sexual encounter. Among the sexually active participants, the incidence of HIV was 1.5 cases / 100 person-years at risk (PYAR, 95% CI: 0.4-6.0), the incidence of chlamydia was 15.7 cases (95% CI: 10.1-24.4), gonorrhea was 4.7 cases (95% CI: 2.1-10.5), and HSV was 6.3 cases (95% CI: 3.1-12.6); we observed no cases of incident syphilis. The incidence of pregnancy among sexually active girls was 15.0 pregnancies / 100 PYAR (95% CI: 8.5-26.5). Despite small numbers, the incidence of most STIs was significantly higher in females compared to males. We also observed two pregnancies and 5 incident STIs among participants who reported never having had sex, these tended to be younger participants. From March to September 2020, the clinic was shut down for COVID-19, and 53 study visits were postponed. Follow up was concluded in November 2020, a total of 19 participants were lost to follow up, however only one participant dropped off-study during COVID-19 shutdowns. Retention at the final visit was 91.5%. We successfully completed a prospective study of adolescents to learn more about the risks they face as they navigate sexual debut in the context of a program of youth-friendly counseling and services. Among self-reported sexually active participants, we observed a high rate of HIV, STI and pregnancy, however we also observed pregnancy and STIs among those who reported no sexual activity.

First Report of Nigrospora oryzae Causing Leaf Spot Disease on Amorphophallus albus in Shaanxi Province of China.

Amorphophallus albus P. Y. Liu & J. F. Chen is a typical cash crop widely planted in southwest China (Gao et al., 2022). In early August of 2021, a peculiar leaf spot disease was first detected on A. albus in Ankang Academy of Agricultural Sciences manufacturing base (32°69'N, 109°02'E), Shaanxi, China. Small irregular yellow-brown spots (1 to 2 mm) were observed on the surface of A. albus leaf. Following infection of the leaf, it expanded (3 to 5 mm) and became necrotic. Nine planting bases were investigated, and approximately 75% of plants were symptomatic during the rapid expansion period of bulb growth in Hanyin, Langao and Hanbin counties, Ankang City, Shaanxi, China. Higher disease incidence was observed at temperatures above 30℃ and humidity above 80%. Twenty-seven symptomatic tissues of infected leaves were first surface sterilized by immersion in 75% ethanol for 1 minute, followed by rinsing three times in sterile distilled water. The tissues were then cut into 4-5 mm pieces, plated on 1.5% potato dextrose agar (PDA), and incubated at 28±2°C. The hyphal tip from the growing edge of colonies cultured for three days at 28±2℃ was transferred to PDA to obtain pure cultures. Fungal colonies were white, then grey to black with an unevenly distributed, fast-growing aerial mycelium covering the petri dish within five days at 28±2℃. The colony turned dark brown when maintained in the dark at 28±2℃ after seven days, then grayish brown upon sporulation after 15 days (Fig.1f-g). Conidia were brown or black, smooth, spherical to sub-spherical, single-celled (8-12 µm × 10-13µm, average 9-11.5 µm in diameter, n=5µm). The nutritional hyphae exhibited septa, and a portion of the aerial hyphae formed a long, rough conidium, giving rise to a nearly spherical apical sac (Fig.1h). The surface gave rise to several small peduncles bearing clusters of surfaced spherical conidia (Fig.1i). Surfaced spherical conidia were generated on the surface of the small peduncle (Fig.1j). These morphological features were consistent with Nigrospora oryzae (Li et al., 2017). Genomic DNA was extracted from mycelia of the pathogen using an Ezup column fungal genomic DNA extraction kit (Sangon Biotech, Shanghai, China). To confirm the identity of the pathogen, the genomic fragments for the internal transcribed spacer (ITS), LSU (28S) and BenA gene of the isolate were amplified by PCR (Wang et al., 2017) and sent for sequencing. The resultant sequence (GeneBank ID of gene ITS, LSU, BenA are OR723825, OR775345, OR277316, respectively) were compared with the voucher specimens. BLAST results showed >99% identity with those of N.oryzae (GeneBank ID of N.oryzae strain LC2707 ITS, LSU, BenA are KX985954, KY806242, KY019481, respectively). A neighbor joining phylogenetic tree with the concatenated sequences of these genes showed that A-pb169 had the closest match with N. oryzae (Fig. 2). For pathogenicity testing, fifty plants in a period of rapid expansion of bulb growth were selected. Four leaves per plant were inoculated by sprayed till runoff with a conidial suspension of the pathogen (50 µL, 1×106 conidia/ml sterile water), and incubated at 30±2℃ and 80 ± 5% humidity. Control plants received sterile water. On the third day after inoculation, a yellow-brown spot appeared on leave surfaces, the spot gradually expanded; the infection rate was 90 to 95%. Fifteen days after inoculation, infected leaves showed symptoms like those observed in the field, whereas 100 control leaves sprayed with sterile water remained symptomless (Fig.1 a-e). The pathogen was reisolated from infected leaves and confirmed as N. oryzae by morphology and molecular identification. To our knowledge, this is the first report of leaf spot disease of A. albus caused by N. oryzae in China. Since its one of the major cash crops of the southeastern China, further work is necessary to determine its spread and economic impact as well as developing sustainable disease management options.