Later Stages Of Growth Research Articles

Field margins and botanical insecticides enhance Lablab purpureus yield by reducing aphid pests and supporting natural enemies.

Botanical insecticides offer an environmentally benign insect pest management option for field crops with reduced impacts on natural enemies of pests and pollinators while botanically rich field margins can augment their abundance. Here, we evaluated the non‐target effects on natural enemies and pest control efficacy on bean aphids in Lablab of three neem‐ and pyrethrum‐based botanical insecticides (Pyerin75EC®, Nimbecidine® and Pyeneem 20EC®) and determine the influence of florally rich field margin vegetation on the recovery of beneficial insects after treatment. The botanical insecticides were applied at the early and late vegetative growth stages. Data were collected on aphids (abundance, damage severity and percent incidence) and natural enemy (abundance) both at pre‐spraying and post‐spraying alongside Lablab bean yield. The efficacy of botanical insecticides was similar to a synthetic pesticide control and reduced aphid abundance by 88% compared with the untreated control. However, the number of natural enemies was 34% higher in botanical insecticide‐treated plots than in plots treated with synthetic insecticide indicating that plant‐based treatments were less harmful to beneficial insects. The presence of field margin vegetation increased further the number of parasitic wasps and tachinid flies by 16% and 20%, respectively. This indicated that non‐crop habitats can enhance recovery in beneficial insect populations and that botanical insecticides integrate effectively with conservation biological control strategies. Higher grain yields of 2.55–3.04 and 2.95–3.23 t/ha were recorded for both botanical insecticide and synthetic insecticide in the presence of florally enhanced field margins in consecutive cropping seasons. Overall, these data demonstrated that commercial botanical insecticides together with florally rich field margins offer an integrated, environmentally benign and sustainable alternative to synthetic insecticides for insect pest management and increased productivity of the orphan crop legume, Lablab.

Variations in Plant Water Use Efficiency Response to Manipulated Precipitation in a Temperate Grassland

Water use efficiency (WUE) plays important role in understanding the interaction between carbon and water cycles in the plant-soil-atmosphere system. However, little is known regarding the impact of altered precipitation on plant WUE in arid and semi-arid regions. The study examined the effects of altered precipitation [i.e., ambient precipitation (100% of natural precipitation), decreased precipitation (DP, −50%) and increased precipitation (IP, +50%)] on the WUE of grass species (Stipa grandis and Stipa bungeana) and forb species (Artemisia gmelinii) in a temperate grassland. The results found that WUE was significantly affected by growth stages, precipitation and plant species. DP increased the WUE of S. grandis and S. bungeana generally, but IP decreased WUE especially in A. gmelinii. And the grasses had the higher WUE than forbs. For different growth stages, the WUE in the initial growth stage was lower than that in the middle and late growth stages. Soil temperature, available nutrients (i.e., NO3–, NH4+, and AP) and microorganisms under the altered precipitations were the main factors affecting plant WUE. These findings highlighted that the grasses have higher WUE than forbs, which can be given priority to vegetation restoration in arid and semi-arid areas.

Estimation of Landsat-like daily evapotranspiration for crop water consumption monitoring using TSEB model and data fusion.

Evapotranspiration (ET) plays an essential role in agricultural water resource management. Understanding regional agricultural water consumption characteristics can be improved by predicting ET using remote sensing. However, due to the lack of high-resolution images on clear-sky days or the limitation of ET reconstruction on cloudy-sky days, it remains challenging to continuously derive ET at the field scale. In this study, the Landsat and MODIS data were initially fused to obtain the Landsat-like vegetation index and land surface temperature on clear-sky days. Then the two-source energy balance (TSEB) model was applied to calculate the daily ET during the clear-sky. A canopy resistance-based gap-filling method was involved in reconstructing regional ET on cloudy days while considering different environmental factors. The estimations were validated by automatic weather system data (AWS) and eddy covariance (EC) measurements in Guantao County. The results demonstrated that the proposed scheme performed well in estimating cropland ET, with an RMSE of 0.86 mm·d−1 and an R2 of 0.65, and the NSE and PBias were 0.61 and -0.29%, respectively. The crop water consumption analysis revealed that the daily ET of winter wheat peaked during the maturation stage. Nevertheless, summer maize water consumption peaked in the middle of the growing season in this area. The temperature during the early development stage and the soil moisture in the mid and late growth stages had the greatest impact on the ET of winter wheat. During the entire growing period, soil moisture had the largest effect on the ET of summer maize. The findings showed that the TSEB model can be effectively applied to field-scale water consumption monitoring in North China through MODIS and Landsat data fusion and ET temporal reconstruction considering environmental factors.

Weed management strategies in Soybean (Glycine max) — A review

Soybean (Glycine max L.) being a rainy season crop, faces severe infestation of kharif weeds. Since the crop suppresses weeds due to its dense canopy at later stages of growth, the control of weeds has received very little attention. Weeds offer severe competition to crops during the early stage of growth. The critical crop weed competition period in soybean varies from 15–45 days after sowing (DAS) depending upon location and prevailing environmental conditions. Weeds cause a 26–84% reduction in the yield depending upon the types and intensity of weeds, besides impairing the quality of the produce. Different methods of weed management in field crops include preventive, cultural, mechanical, chemical, biological, and biotechnological means. Weed control through a physical approachachieved by hand weeding at 20 and 40 DAS (twice) is ineffective due to the continuous rainfall and high labour wages. The use of herbicides for the control of weeds has gathered momentum in recent years. Weed control through the integration of herbicides with cultural weeding is a paying proposition. Double knock application of one preemergence herbicide followed by application of post-emergence herbicides, solves the problem of labour scarcity encountered by the farmers. However, the timely application of different weed management tactics has a crucial role in achieving the desired target. Killing one or two flushes before seeding a crop and immediate cultivation of field after harvest to destroy survivors has an added advantage. An effort has been made in this article to review the work done on weed management in soybean

Integrated transcriptome and endogenous hormone analysis provides new insights into callus proliferation in Osmanthus fragrans

Osmanthus fragrans is an important evergreen species with both medicinal and ornamental value in China. Given the low efficiency of callus proliferation and the difficulty of adventitious bud differentiation, tissue culture and regeneration systems have not been successfully established for this species. To understand the mechanism of callus proliferation, transcriptome sequencing and endogenous hormone content determination were performed from the initial growth stages to the early stages of senescence on O. fragrans calli. In total, 47,340 genes were identified by transcriptome sequencing, including 1798 previously unidentified genes specifically involved in callus development. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of differentially expressed genes (DEGs) was significantly enriched in plant hormone signal transduction pathways. Furthermore, our results from the orthogonal projections to latent structures discrimination analysis (OPLS-DA) of six typical hormones in five development stages of O. fragrans calli showed jasmonic acid (JA) could play important role in the initial stages of calli growth, whereas JA and auxin (IAA) were dominant in the early stages of calli senescence. Based on the weighted gene co-expression network analysis, OfSRC2, OfPP2CD5 and OfARR1, OfPYL3, OfEIL3b were selected as hub genes from the modules with the significant relevance to JA and IAA respectively. The gene regulation network and quantitative real-time PCR implied that during the initial stages of callus growth, the transcription factors (TFs) OfERF4 and OfMYC2a could down-regulate the expression of hub genes OfSRC2 and OfPP2CD5, resulting in decreased JA content and rapid callus growth; during the late stage of callus growth, the TFs OfERF4, OfMYC2a and OfTGA21c, OfHSFA1 could positively regulate the expression of hub genes OfSRC2, OfPP2CD5 and OfARR1, OfPYL3, OfEIL3b, respectively, leading to increased JA and IAA contents and inducing the senescence of O. fragrans calli. Hopefully, our results could provide new insights into the molecular mechanism of the proliferation of O. fragrans calli.

Effects of cotton stubble return and subsoiling on dry matter accumulation, nutrient uptake, and yield of cotton in coastal saline-alkali soil

<p id="C3">To study the effects of cotton straw returning and deep loosening on cotton yield, salt content in 0-40 cm soil layer, dry matter accumulation dynamics, nitrogen (N), phosphorus (P), and potassium (K) accumulation, and distribution characteristics, four treatments including conventional tillage (CT), subsoiling tillage (ST), cotton stubble return (SR), and cotton stubble return + subsoiling tillage (SRT) were conducted using Lumianyan 36 as experimental material. The results showed that cotton stubble return increased cotton yield across two years. Lint yield of SR was 33.9% higher than CT, and SRT 32.1% higher than SR. Subsoiling increased cotton yield in 2017 and had no effect on it in 2018. Cotton stubble return reduced the salt content of 0-40 cm soil layer. The salt content of SR was 22.4% lower than that of CT, and the soil salt content of SRT was 20.7% lower than that of ST at the late growth stage in cotton. However, the effect of subsoiling on the salt content of 20-40 cm soil layer was inconsistent during the two-year experiment. The soil salt content of ST was 16.5% lower than of CT at late growth stage in 2017, but subsoiling had no effect on soil salt content in 2018. The accumulation dynamic of dry matter and N, P, K in cotton were consistent with the Logistic growth curve. Cotton stubble return increased maximal accumulation of dry matter and N, P, K in two years. The maximum accumulation of dry matter, N, P, and K in SR was 35.5%, 38.3%, 53.4%, and 55.0% higher than that in CT, and the accumulation of SRT was 27.0%, 30.7%, 21.2%, and 42.4% higher than that in ST. Compared with CT, the dry matter, N, P, and K accumulation of ST increased by 17.8%, 22.2%, 51.3%, and 40.6% in 2017, respectively, but had no effect in 2018. The dynamic of dry matter and nutrient accumulation were mainly affected by the maximum accumulation rate and rapid accumulation duration. Stubble return increased the amount and proportion of dry matter and N, P, K allocated to reproductive organs of cotton in the two-year experiment. Compared with CT, ST increased the allocation amount of dry matter and N, P, K to reproductive organs in 2017, but had no effect in 2018. In summary, the results revealed that cotton stubble return (SR) or cotton stubble return + subsoiling tillage (SRT) could be recommended tillage measures for soil improvement and high cotton yield in coastal saline-alkali cotton area.

Changes in Patellofemoral Joint Morphology During Skeletal Growth and Maturation are not Sex-Dependent

Background:Patellofemoral disorders account for approximately 25% of patients seen in sports medicine clinics. A variety of anatomic risk factors have been identified in the pathogenesis of patellofemoral instability. While studies have analyzed these factors in adults, or compared them between healthy controls and patients with patellar injuries, little is known about how these anatomic markers change during skeletal growth and development.Hypothesis/Purpose:(A) The anatomic risk factors associated with patellar instability and dislocation change significantly during skeletal maturation. (B) These age-related changes during maturation will differ between male and female patients.Methods:After institutional review board approval, magnetic resonance imaging data from 239 unique knees (patient age 7-18; 55% female), without previous or current injury, were randomly selected and used to measure patellar height, lateral patellar tilt angle, trochlear width, trochlear depth, trochlear sulcus angle, and tibial tubercle trochlear groove distance. Linear regression was used to test the associations between age and anatomic measurement indices. Subsequently, patients were divided into four age groups: pre-pubertal school-aged children (7-10 years old), early adolescents (11-14 years old), and late adolescents (15-18 years old). Additionally, two-way analysis of variance with the Holm-Sidak post hoc test was used to compare anatomic morphologies between male and female patients in each age group.Results:Patellar height (Caton-Deschamps index), lateral patellar tilt angle and trochlear sulcus angle all decreased significantly with age (P<0.001). Trochlear width, depth, and tibial tubercule trochlear groove distance all increased significantly with age (P<0.001). Except for trochlear width in late adolescence (P<0.001) where males had wider trochlea (medial and lateral) compared to matched females, the age-related anatomic changes were similar between males and females (P>0.1).Conclusion:The findings partially support our hypothesis, as we observed significant age-related changes in all quantified anatomical indices, which was not different (except trochlear width in late adolescence) between males and females. The lack of significant differences in key morphological features of the patellofemoral joint that are linked to patellar dislocation between females and males is consistent with a similar prevalence of this injury between the two. However, the findings suggest that there are significant differences in the trochlear width between females and males at later stages of growth and maturation. The current observations suggest that these anatomic risk factors undergo significant changes during skeletal growth, providing us with a window of opportunity to use prophylactic interventions to prevent or minimize the development of high-risk morphology.Figure 1.1.CDI: Caton-Deschamps Index; TD: Trochlear Depth; TSA: Trochlear Sulcus Angle; LPTA: Lateral Patellar Tilt Angle TTTG: Tibial Tubercle Trochlear Groove Distance.Figure 1.2.Age- and sex-dependent changes in patellofemoral joint morphology during skeletal growth and maturation. Data are presented as mean and SEM (* P<0.05).

Pre-anthesis night warming improves post-anthesis physiological activity and plant productivity to post-anthesis heat stress in winter wheat (Triticum aestivum L.)

Global warming is asymmetric, with the increase in temperature at night being greater than that during the day. In this study, we conducted night warming treatments using a passive heating device on the wheat variety ‘Yangmai 18′ grown in culture pots in an experimental field. The night warming treatments were performed from the tillering stage to the jointing stage (NW T-J ), from the jointing stage to the booting stage (NW J-B ), and from the booting stage to the anthesis stage (NW B-A ). A non-warming treatment was used as a control (NN). Post-anthesis heat (H) stress was performed during the grain-filling stage. The results showed that treatments NW T-J and NW J-B significantly enhanced grain yield by increasing the 1000-grain weight, while the NW J-B treatment showed the highest impact. Night warming treatments at early growth stages significantly prevented the grain-yield reduction caused by heat stress during grain filling. NW J-B treatment increased the sucrose content and sucrose phosphate synthase (SPS) activity of the flag leaves under heat stress during grain filling, which increased the ability of the plants to convert post-anthesis photoassimilates into sucrose, providing a basis for the accumulation of sucrose in the grains. Meanwhile, NW J-B treatment increased the ability of the plants to assimilate and utilize nitrogen by increasing the nitrogen content and activity of nitrate reductase (NR) and glutamine synthetase (GS) of the flag leaves under heat stress during grain filling. Post-anthesis assimilation products and the activities of the enzymes related to carbon and nitrogen metabolism in wheat plants subjected to night warming treatments maintained at a higher level, which promoted the formation and conversion of proteins and starches in the grains at the late growth stages. Night warming treatments from the jointing to booting stage effectively improved post-anthesis physiological activity and plant productivity, which reduced yield loss caused by heat stress during grain filling. • Night warming priming at early growth stages increased the photosynthetic assimilation capacity of the wheat. • Night warming priming at early growth stages also increased the ability of wheat to accumulate and transfer nitrogen under heat stress during grain filling. • Night warming priming from the jointing to booting stage showed the highest impact.

Spatial distribution and correlation of dominant species of karst secondary forest in central Guizhou, China

We analyzed the spatial distribution pattern and correlation of the top four dominant tree species in a 2 hm2 karst secondary forest plot of Tianlong Mountain in central Guizhou, using pairwise correlation function g(r) combined with a completely random model (CSR). The results showed that the diameter structure of trees followed an inverted J-shape, and that more trees belonged to diameter class Ⅴ (≥10 cm) driven by the dominant trees of Lithocarpus confinis and Platycarya longipes. L. confinis presented an inverted J-shaped distribution, and the population could renew very well and was in the primary growth stage. The abundance of P. longipes and Itea yunnanensis increased gradually with increasing diameter class. The density of grown and large trees was far more than the young and small individuals, which indicated poor population regeneration, and the population was in the middle and late growth stages. The top dominant tree species, except L. confinis, showed clustering distribution at large scale, which was decreased gradually with scale and trended to distribute randomly. The pattern was particularly prominent in the diameter class for young trees. Different diameter classes of different tree species presented diffe-rent spatial distribution patterns which influenced by many factors. In terms of interspecific associations, the four dominant tree species showed negative or no associations. The higher importance value of tree species, the lower the degree of association with other dominant species. The two negative correlation tree species had the lowest degree of correlation at small scale. With the increase of spatial scale, the degree of negative correlation decreased gradually, and tended to be no correlation.

Automated soybean mapping based on canopy water content and chlorophyll content using Sentinel-2 images

Accurate and timely spatiotemporal distribution information of soybean is vital for sustainable agriculture development. However, it is challenging to establish a phenology-based automated crops mapping algorithm at large spatial domains by simply applying vegetation index temporal profile. This study developed a Phenology-based automatic Soybean mapping algorithm through combined Canopy water and Chlorophyll variations (PSCC). Three phenology-based indices were designed: the ratio of change magnitudes of vegetation index to water stress index during the late growth stage (T1), the mean concentration of chlorophyll during the whole growth period (T2), and the accumulated variations of chlorophyll before and after heading date (T3). Soybean was distinguished by lower T1 and T3 and higher T1 due to higher senescence water loss and chlorophyll content. The PSCC method was validated in Northeast China from 2017 to 2021 and in four states (Missouri, Illinois, Indiana, and Ohio) of the United States (US) in 2020 using Sentinel-2 datasets. Soybean planting areas obtained by PSCC were consistent with the corresponding agricultural statistical area (R2 > 0.83). The soybean maps were evaluated using 5702 reference data, and the overall accuracy and kappa coefficient were 91.99% and 0.8338, respectively. The overall accuracy for soybean mapping was improved by 16.07% compared with using only canopy water variation. The result showed that our method could be applied to large spatial domains and multi-years without retraining. The soybean planting area in Northeast China expanded substantially 25,867 km2 (by 89.10%) during the period 2015–2020 and decreased slightly 7,535 km2 (by 13.73%) from 2020 to 2021. Soybean expansion occurred mainly in ever-planted regions. Northeast China contributed about 60% to the national soybean revitalization goal in 2020. This study provided information on the soybean spatiotemporal changes in Northeast China, which was significant for agricultural policymakers to formulate soybean production plans to achieve national soybean revitalization.

Molecular-level characteristics of soil organic carbon in rhizosheaths from a semiarid grassland of North China

Rhizosheaths are aggregated, sheath-like soils that physically adhere to root surface, and they form on herbaceous plant roots worldwide, especially in semiarid grasslands. Representing a strong root−soil−microbe interaction, the rhizosheaths are expected to have distinct soil organic carbon (SOC) signatures from rhizosphere soils of non-rhizosheath forming plants. However, such signatures remain unclear, which hinders our understanding of root effects on SOC cycling in grasslands. We compared SOC characteristics between rhizosheath and non-rhizosheath soils of eight herbaceous plant species, collected from a semiarid grassland of North China, using solid-state 13C nuclear magnetic resonance spectroscopy and biomarker analyses. We further examined the temporal dynamics of SOC characteristics of rhizosheath soils from early, middle, and late plant growth stages. Compared to non-rhizosheath SOC, rhizosheath SOC had more root inputs of both labile substrates (carbohydrates and free alkanoic acids) and relatively recalcitrant suberin- and lignin-derived compounds. Moreover, the labile inputs provided more substrates for microbial degradation of cutin-derived compounds. These indicators of labile substrate availability increased significantly from the early to late growth stages. Overall, our findings clarify the molecular characteristics of rhizosheath SOC and its temporal dynamics, both of which suggest a critical role of rhizosheath in shaping the rhizosphere microenvironment and regulating SOC cycling.

Source-Sink Dynamics in Field-Grown Durum Wheat Under Contrasting Nitrogen Supplies: Key Role of Non-Foliar Organs During Grain Filling.

The integration of high-throughput phenotyping and metabolic approaches is a suitable strategy to study the genotype-by-environment interaction and identify novel traits for crop improvement from canopy to an organ level. Our aims were to study the phenotypic and metabolic traits that are related to grain yield and quality at canopy and organ levels, with a special focus on source-sink coordination under contrasting N supplies. Four modern durum wheat varieties with contrasting grain yield were grown in field conditions under two N fertilization levels in north-eastern Spain. We evaluated canopy vegetation indices taken throughout the growing season, physiological and metabolic traits in different photosynthetic organs (flag leaf blade, sheath, peduncle, awn, glume, and lemma) at anthesis and mid-grain filling stages, and agronomic and grain quality traits at harvest. Low N supply triggered an imbalance of C and N coordination at the whole plant level, leading to a reduction of grain yield and nutrient composition. The activities of key enzymes in C and N metabolism as well as the levels of photoassimilates showed that each organ plays an important role during grain filling, some with a higher photosynthetic capacity, others for nutrient storage for later stages of grain filling, or N assimilation and recycling. Interestingly, the enzyme activities and sucrose content of the ear organs were positively associated with grain yield and quality, suggesting, together with the regression models using isotope signatures, the potential contribution of these organs during grain filling. This study highlights the use of holistic approaches to the identification of novel targets to improve grain yield and quality in C3 cereals and the key role of non-foliar organs at late-growth stages.

Nitrogen Modulates the Effects of Short-Term Heat, Drought and Combined Stresses after Anthesis on Photosynthesis, Nitrogen Metabolism, Yield, and Water and Nitrogen Use Efficiency of Wheat

More frequent and more intense heat waves and greater drought stress will occur in the future climate environment. Short-term extreme heat and drought stress often occur simultaneously after winter wheat anthesis, which has become the major constraint threatening future wheat yield. In this study, short-term heat, drought and their combination stress were applied to wheat plants after anthesis, and all wheat plants were restored to the outdoor normal temperature and full watering after stress treatment. The aim of the current study was to evaluate the role of nitrogen (N) in modulating the effects of post-anthesis short-term heat, drought and their combination stress on photosynthesis, N metabolism-related enzymes, the accumulation of N and protein and growth, as well as on the yield and water (WUE) and N use efficiency (NUE) of wheat after stress treatment. The results showed that compared with low N application (N1), medium application (N2) enhanced the activities of nitrate reductase (NR) and glutamine synthase (GS) in grains under post-anthesis heat and drought stress alone, which provided a basis for the accumulation of N and protein in grains at the later stage of growth. Under post-anthesis individual stresses, N2 or high application (N3) increased the leaf photosynthetic rate (An), PSII photochemical efficiency and instantaneous WUE compared with N1, whereas these parameters were usually significantly improved by N1 application under post-anthesis combined stress. The positive effect of increased An by N application on growth was well represented in a higher green leaf area, aboveground dry mass and plant height, and the variation in An can be explained more accurately by the N content per unit leaf area. Short-term heat, drought and combined stress after anthesis resulted in a pronounced decrease in yield by reducing grain number per spike and thousand kernel weight. The reduction in NUE under combined stress was higher than that under individual heat and drought stress. Compared with N1, N2 or N3 application significantly prevented the decrease in yield and NUE caused by post-anthesis heat and drought stress alone. However, N1 application was conducive to improving the productivity, WUE and NUE of wheat when exposed to post-anthesis combined stress. The current data indicated that under short-term individual heat and drought stress after anthesis, appropriately increasing N application effectively improved the growth and physiological activity of wheat compared with N1, alleviating the reduction in yield, WUE and NUE. However, under combined stress conditions, reducing N application (N1) may be a suitable strategy to compensate for the decrease in yield, WUE and NUE.

Origin and distribution of calcite cements in a folded fluvial succession: The Puig‐reig anticline (south‐eastern Pyrenees)

AbstractAs one of the predominant diagenetic products in clastic rocks, calcite cements are typical fingerprints of cement‐forming fluids and are key controls on reservoir quality. The Puig‐reig anticline, in the south‐eastern Pyrenees (Spain), exposes excellent outcrops of conglomerates, sandstones and claystones, which were deposited from a proximal to medial fluvial system and underwent folding, fracturing and cementation. This anticline constitutes an appropriate case study to investigate the origin and distribution of calcite cements during folding evolution and how they affect reservoir quality. Based on structural, petrographic and geochemical analyses (carbon, oxygen, strontium and clumped isotopes and elemental composition), five generations of calcite cements (‘Cc0’ to ‘Cc4’) have been identified, filling intergranular porosity of host rocks, faults and four fracture sets (F1 to F4). Calcite cement Cc0 precipitated in intergranular porosity from meteoric fluids in the phreatic zone during the early diagenetic stage. During the most intense phase of thrusting and folding, Cc1 precipitated in intergranular porosity, faults and F1 to F4 fracture sets from hydrothermal fluids that migrated from deeper areas of the Pyrenean chain. During the late stage of fold growth, Cc2 precipitated in faults and their associated fractures in the anticline crest from hydrothermal fluids but at shallower burial depths than that of Cc1. Calcite cement Cc3 mainly precipitated in fractures with the same strike as F1 and F4 fracture sets in the north‐western part of the anticline, from formation fluids that probably migrated through the frontal thrust of the south‐eastern Pyrenees. During the continuous fold denudation, Cc4 precipitated from meteoric fluids in F1 to F4 fracture sets across the anticline. Results indicate that at foreland basin margins, external fluids coeval with compressional deformation and/or alteration of detrital carbonates contribute to intensive calcite cementation. This can result in an overall occlusion of porosity and significantly damaged reservoir quality.

Effects of plastic film mulch biodegradability on nitrogen in the plant-soil system

The application of biodegradable film mulching (BFM) instead of non-biodegradable film mulching (NBFM) is a promising way to mitigate the negative impacts of residual film in agricultural mulching systems. But the effects of BFM on soil mineral nitrogen (N) are not known. To investigate the effects of BFM on N mineralization, nitrate (NO3−) accumulation and leaching, and plant N uptake, we conducted two-year field experiment with five treatments: no-mulching (No-M), white non-biodegradable film mulching (White-NotBioM), black non-biodegradable film mulching (Black-NotBioM), white biodegradable film mulching (White-BioM), and black biodegradable film mulching (Black-BioM). The net N mineralization in NBFM was greater than that in BFM due to the disintegration of biodegradable films in the middle and late stages of maize growth, resulting in a decrease in soil water content under BFM. Higher net N mineralization caused a higher NO3− accumulation in the topsoil (0–20 cm) under NBFM. The NO3− accumulation in the topsoil in Black-NotBioM was 23–88% higher than that in Black-BioM; while in White-NotBioM it was 16–63% higher than that in White-BioM. After two years of cropping, the NO3− accumulation in 100–180 cm (defined as N leaching in deep layers, NLD) in NBFM was 52–63% higher than that in BFM, implying that the higher NO3− accumulation in the topsoil in NBFM caused more N leaching. The yields and plant N uptake were similar between NBFM and BFM, but BFM had higher N harvest index values. Compared with NBFM, BFM showed less NO3− accumulation in the topsoil and less NLD, whereas yield, plant N uptake and net economic benefits were not reduced. Therefore, BFM, especially Black-BioM, could be an alternative to NBFM in maize production on the Loess Plateau. However, the higher N accumulation in root soil layer (0–100 cm) under Black-BioM should be accounted for in N fertilizer management.

Drought escape during the late growth stage through early recovery from initial drying stress by hydropriming of upland rice

ABSTRACT This study investigated the interactions between soil moisture conditions and seed priming on initial and late growth over 2 years (2017–2018) through field trials and container experiments with regulated soil moisture. Field trials were conducted on rainfed upland rice fields in Uganda, East Africa, where primed and control seeds were planted in triplicate and cultivated. In 2017, the percentage of first heading (head emergence) of hills was higher in priming treatments, and the time for 20% of the hills to achieve the first heading (H20) was significantly earlier than in controls. Additionally, grain ratio (number of fertile grains to sterile grains) and H20 were negatively correlated (P < 0.05). However, the difference in growth parameters between control and priming was not found in the case of 2018. The results suggested that priming reduces the growth period under certain conditions and improves drought escape. Therefore, we investigated the relationship between priming effects on initial growth under soil moisture treatments and subsequent development under waterlogged conditions. After transfer to waterlogged conditions, plants of the primed seeds initially grown in low soil moisture conditions recovered earlier than control plants. Our research concludes that the agronomical impact of hydropriming on upland rice prevents prolonged plant growth under drought by early recovery. Furthermore, it could decrease the yield loss caused by reduced rainfall in the late growth stage.

Optimizing planting pattern and nitrogen application rate improves grain yield and water use efficiency for rain-fed spring maize by promoting root growth and reducing redundant root growth

Improving root growth is essential for enhancing the capacity of crops to acquire soil resources but redundant root growth can also limit productivity, especially in rain-fed farming areas where resources are limited. We conducted a two-year field experiment in the Loess Plateau region of China to explore the effects of different planting patterns (flat planting without film mulching; ridge–furrow plastic film mulching planting with three ridge–furrow ratios of 40:70 cm, 55:55 cm, and 70:40 cm) and nitrogen application rates (180 kg ha –1, 240 kg ha –1, and 300 kg ha –1) on the growth and activity of roots, root–shoot relationship, and grain yield and WUE of rain-fed spring maize. The planting pattern and nitrogen application rate only affected the root characteristic parameters in the shallow soil layer (0–40 m), where these parameters all increased as the ridge–furrow ratio and nitrogen application rate increased. The improvements in the root characteristic parameters were beneficial for increasing the root bleeding sap rate. The root–shoot ratio was only affected by the planting pattern. Compared with flat planting, increasing the ridge–furrow ratio enhanced the root–shoot ratio in the early growth stage, which was beneficial for allowing roots to acquire soil resources and promoting canopy establishment; however, the opposite results were observed in the late growth stage, thereby suggesting that increasing the ridge–furrow ratio promoted the distribution of dry matter to the shoots and reduced redundant root growth. The spring maize grain yield and water use efficiency were significantly positively correlated with the root characteristic parameters and the root bleeding sap rate but negatively correlated with the root–shoot ratio, thereby explaining the increases in the grain yield and water use efficiency as the ridge–furrow ratio and nitrogen application rate increased. However, there were generally no significant differences in the grain yield and water use efficiency between 240 kg ha −1 and 300 kg ha −1 under the same planting pattern. Therefore, the combination of ridge-furrow plastic film mulching planting with three ridge-furrow ratios of 70:40 cm and 240 kg ha −1 may be applied as a suitable field management practice for rain-fed spring maize production in the Loess Plateau region.

Metabolomics integrated with transcriptomics reveals the changes during developmental stages in Shiraia bambusicola.

Shiraia bambusicola is a fungus with high economic value widely used in medicine, agriculture, and food. We wishedto understand the genes and metabolites changes involved in the different developmental stages of S. bambusicola. So, to reveal key genes and metabolites in the main active metabolite,the were analyzed in different developmental stages of S. bambusicola fruiting body. A total of 29,137 Unigenes were annotated. In the whole growth process, differentially expressed genes were involved in the pathways of cytochrome P450, transcription factors, transporters, and so on, while in the early stage of growth, genes enriching to synthesis pathways of basic substances. In the middle stage of growth, genes with more prominent changes were involved in the pathways of the cell cycle, cancer mechanisms, and aminobenzoate degradation; in the later stage of growth, differentially expressed genes that enriched synthesis pathways of secondary metabolites. A total of 612 metabolites were detected from different growth stages of S. bambusicola. Among them, coumarins, alkaloids, rutin, liquiritigenin, quercetin, and other medically relevant metabolites were detected for the first time. We have identified 31 secondary metabolites, relevantly only accumulated in the early and middle stage, but not detected in the later stage, such as flavonols, coumarins, nucleotides and its derivatesand hydroxycinnamoyl derivatives. The differential genes and metabolites of the same group were enriched in 127 pathways, and more significantly in ubiquinone and other terpenoid quinone biosynthesis, phenylalanine metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, and phenylpropanoid biosynthesis. The correlation networks of several significantly enriched pathways were analyzed, andthe relationships within and between these pathways, genes, and metabolites, were analyzed. The synthetic pathway of hypocrellin hasbeen speculated upon. We believe that hypocrellin is synthesized in S. bambusicola via the shikimic acid pathway followed by phenylalanine, tyrosine, and tryptophan biosynthesis pathway, then the ubiquinone and other terpenoid quinone biosynthesis pathway, and finally a series of polymerization and modification reactions. Several genes and metabolites involved in the biosynthesis of hypocrellin have been identified. This study provides a reference for further research on S. bambusicola, by providing a basis for its use and development.

First Report of Leaf Spot Caused by Didymella americana on Cassia nomame in China.

Cassia nomame (Sieb.) Kitagawa is an annual plant in the Leguminousae family. The aerial parts of C. nomame have been used as tonic and diuretic in Korea and Japan (Syed et al. 2019). A leaf spot was observed on the leaves of a 1-year-old C. nomame landrace in Changli County (39.42°N, 119.10°E), Qinhuangdao City, Hebei Province during August to October in 2018. In many fields (n≥3), the disease incidence over 80% in the middle and late stage of plant growth. Symptoms on leaves in one field began with many small, dark necrotic spot lesions. Later, the lesions spread to round-to-oval, slightly sunken in the center, and large necrotic patches with indefinite margins. Finally, lesions coalesced and resulted in defoliation. Lesions were occasionally observed on the pods. Symptoms on the pods were initially small, dark spots and then expanded to large necrotic patches with irregular edges. Symptomatic tissues (n=32) from pods and leaves were cut into 3 to 8 mm2 squares, surface disinfested with 75% ethanol for 10 s, rinsed with sterile distilled water, then placed on potato dextrose agar (PDA) at 28℃. After 3 days, ten isolates with consistent characteristics were obtained with a frequency 52.6%. The isolates on PDA were round, initially pale and had little aerial mycelium, gradually turned olive green and had dense wool-like dense aerial mycelia after 3 days. Conidia were hyaline, smooth, solitary, and elliptical. The conidia measured 5.4 to 8.2 μm × 2.5 to 3.8 μm (n=50), and has two oil bodies positioning at opposite poles. Pigmented chlamydospores were spherical or nearly pear-shaped, and solitary. Black fructifications (pycnidia) were produced profusely on PDA after subculture for 3 days. All the isolates were similar to Didymella sp. in morphology (Aveskamp etal.2009). Choice three isolates YSGUO8 YSGGUO8-a and YSGGUO8-b to be further characterized by sequencing of the internal transcribed spacer (ITS), actin gene, and 28S large subunit of the nuclear rRNA gene (LSU) (Zhang et al. 2017). The sequences of three strains (MK836417 MZ484072 and MZ484073 for ITS, MK837604 MZ593675 and MZ593676 for actin, MK843781 MZ836208 and MZ836207 for LSU, respectively) showed 99% to 100% similarity with Didymella americana K-004 (KY070279 for ITS,KY070285 for LSU), Phoma americana CBS 256.65 (FJ426973 for ITS, FJ426871 for actin, MH870196 for LSU) and P. americana CBS 185.85 (FJ426972 for ITS, FJ426870 for actin, GU237990 for LSU) in GenBank. The fungi were identified as D. americana (formerly P. americana or Peyronellaea americana) on the basis of morphological characteristics and sequence analysis. A pathogenicity test was conducted with three times on 1-year-old C. nomame strain at the 4 to 6 compound leaf stage. Conidia were obtained from 7-day-old PDA cultures grown at 28℃ with a 12-h photoperiod. Koch's postulates were fulfilled by spray inoculating ten healthy young plants with 106conidia per milliliter of D. americana strain YSGUO8, and sterile water as the control. After inoculation, the plants were managed at 28℃, 60% relative humidity and a 12-h photoperiod. After 5 to 8 days, the inoculated leaves developed small and dark spots lesions similar to those observed on the leaves with initial symptoms in the field. The control leaves remained symptomless. The same fungi were re-isolated from infected leaves by morphology observation and sequence analysis, confirming Koch's postulates. D. americana has caused leaves spot on Table Beet in New York (Vaghefi et al. 2016). To our knowledge, this is the first report of D. americana causing leaf spot of C. nomame in China.

Effects of increasing panicle-stage N on yield and N use efficiency of indica rice and its relationship with soil fertility

Because of the higher nitrogen (N) recovery efficiency (NRE) of panicle-stage fertilization compared with basal and tillering fertilization, increasing the proportion of N topdressing at the booting stage (panicle-N) is recommended and commonly practiced in parts of China. To investigate the effects of increasing panicle-N on grain yield and N use efficiency (NUE) and the relationships of the increase and the rice cultivar and soil fertility status, we increased the percentage of panicle-N from 20% to 40% by correspondingly reducing the N amount applied only at the tillering stage in both high- and low-fertility blue clayey paddy fields in 2018 and 2019. Four indica cultivars with diverse panicle types were used, and their grain yield, dry matter accumulation, and NUE were compared. In high-fertility soil, increasing topdressing panicle-N from 20% to 40% reduced tillering ability and reduced the effective panicle numbers of the multi- and medium-panicle cultivars Huanghuazhan (HHZ), C Liangyouhuazhan (CHZ), and Tianyouhuazhan (THZ). These cultivars gave the greatest yield when 30% of N was supplied as panicle fertilizer, whereas the yield, NRE, N agronomic efficiency (NAE), and nitrogen physiological efficiency (NPE) of the heavy-panicle inbred cultivar Yangdao 6 (YD6) continued to increase, resulting in improved dry matter accumulation and grain filling in the late growth stage. The yield, NAE, NRE, and NPE of YD6 peaked when the panicle-N constituted 40%. While in low-fertility soil, the multipanicle cultivar HHZ showed the greatest yield when 30% of fertilizer-N was applied once at the panicle initiation (PI) stage, while the medium-panicle cultivar CHZ showed the greatest yield when the panicle-N percentage was 40%. Our results suggest that the percentage of panicle-N fertilizer should not exceed 30% for multipanicle cultivars, while can be appropriately increased to 40% for heavy-panicle indica cultivars. The effect of increasing topdressing panicle-N on the yield of medium-panicle cultivars was related to soil fertility. The optimum panicle-N percentage was 30% in the high-fertility soil and 40% in the low-fertility soil.