[Objective]Sorghum is an important brewing material.The starch content and composition in grains are significant factors affecting the physicochemical properties of sorghum starch.This study aimed to reveal the primary factors influencing the physical and chemical characteristics of starch through the relationship between different starch components and their proper-ties,providing theoretical guidance for the selection and breeding of high-quality sorghum varieties.[Methods]In this study,19 sorghum varieties were used as experimental materials.Measurements were conducted to determine various indicators of differ-ent starch components and gelatinization properties in the grains,and an analysis of the correlation between starch components and gelatinization characteristics were performed.[Results]The average total starch content among the 19 sorghum varieties was 59.55％.The average amylose content was 11.55％,and the resistant starch content averaged at 8.07％.There were sig-nificant differences in resistant starch content among the varieties.The average amylopectin content and its proportion were 48％and 80.75％,respectively.The average amylose to amylopectin ratio was 7.79％.Among the six starch component-re-lated characteristics,three showed a highly significant negative correlation,two showed a highly significant positive correla-tion,and one showed a significant positive correlation.In terms of gelatinization characteristics,final viscosity,lowest viscosi-ty,and breakdown values were significantly influenced by the amylopectin ratio and the amylose-to-amylopectin ratio.Peak vis-cosity,lowest viscosity,and breakdown value also showed a significant relationship with the amylose content but were not sig-nificantly associated with the amylopectin content.Peak viscosity and breakdown value were closely related to the total starch content.The lowest value was significantly correlated with the amylose and amylopectin content,amylopectin proportion,and amylose-to-amylopectin ratio.The resistant starch content in grains mainly affected the peak temperature of the starch.[Conclu-sion]The physicochemical properties of sorghum grain starch were closely related to the starch components and their ratios.It is important in production to select different sorghum varieties with specific starch contents and compositions based on various processing purposes.
Drought is one of the important factors affecting maize production,which exerts adverse effects on plant growth and development.It stands as a primary cause for reduced global maize production,significantly hampering the development of the maize industry.In many regions,the conflict between limited agricultural water resources and the necessity to increase maize productivity to meet the escalating food demands of a growing population continues to escalate.The development of maize vari-eties that are less water-dependent and more tolerant to drought can alleviate this challenge.Given the frequent occurrence of high temperature and drought due to global climate change,conducting research on maize drought resistance and implementing adaptive strategies is highly imperative.Breeders are employing various genetic and breeding methods to develop drought-resis-tant maize varieties.The combination of transcriptomics,proteomics,and other high-throughput omics techniques with new breeding methods can significantly improve drought resistance of maize.In recent years,genetic engineering appears to be a faster and more effective approach in enhancing maize's drought resistance compared to traditional breeding and molecular marker-assisted selection strategies.Techniques such as transgenic and genome editing have shown rapid enhancements in maize tolerance to drought stress.This paper presents maize's response to drought resistance and explores the application of new breeding and systems biology methods to resolve the physiological basis and molecular mechanism of maize's drought resis-tance,offering insights for the development of drought-tolerant varieties and further improving maize yield.
[Objective]Under high-density planting conditions for maize,leaf redundancy exists.Moderate defoliation can aid in redistributing internal resources and improve maize yield.[Methods]This study,conducted in 2021 and 2022,utilized the com-pact maize variety Zhengdan958.A two-factor split-zone experimental design was used,with the primary factor focusing on planting density:conventional density(67 500 plants·hm-2)and high-density(97 500 plants·hm-2).The secondary factor in-volved source reduction intensity:removing the top 2,4,and 6 leaves of the plant 7 days after silking,with the treatment of no leaf reduction served as the control.Analysis of maize plant morphology,photosynthetic performance,root characteristics,and yield components was carried out at the stages of anthesis,grain filling,milky,and waxing stages to investigate the response of maize photosynthetic performance and root characteristics to reduced leaf source.[Results]The results of the study demonstrat-ed that leaf removal at conventional density did not enhance maize's photosynthetic performance,while removing the top two leaves under high-density planting conditions delayed the senescence of the remaining leaves,slowed the decline of the leaf area index,and increased the population photosynthetic rate(CAP)by 24.5％during the filling period compared to the control.Un-der conventional density planting conditions,defoliation was detrimental to deep root growth and reduced root activity.Howev-er,under high-density planting,defoliation encouraged root growth in the 40～100 cm soil layer,resulting in a 53.7％increase in root dry wright at the wax maturity stage compared to the control,with root activity increasing by 7.0％.Removing 2,4,or 6 leaves under conventional density resulted in yield reduction of 7.5％,21.7％,and 26.5％,respectively.In contrast under high-density planting conditions,removing 2 leaves increased kernel yield by 7.8％compared to the control,while excessive source reduction treatments(removing 4 or 6 leaves)reduced maize yield by 14.5％and 22.7％,respectively.[Conclusion]It is evident that reducing the leaf source at conventional density is detrimental to maize growth.However,moderately reducing the leaf source under high-density planting conditions significantly improved maize photosynthetic performance,enhanced root characteristics,and ultimately increased maize yield.
[Objective]Primary trisomics is an essential genetic research materials.This study aimed to create a primary trisomics of petunia(Petunia hybrida Vilm)and conducted related cytological and physiological studies.[Methods]In this study,the white variety diploid and triploid of petunia were used as materials.Two primary trisomies,designated as No.6 and No.7,were selected from the progenies of the backcross between triploid and diploid through chromosome counting and karyotype analysis.Comparative observations of agronomic traits and determination of pollen fertility were conducted with diploid as the control.Meiosis of the primary triploid pollen mother cells was observed at different stages using conventional meiotic division compression method.Physiological indicators including chlorophyll content,cell membrane permeability,malondialdehyde content,superoxide dismutase activity,and peroxidase activity were determined under drought stress conditions for both prima-ry triploids and diploid.The average membership function values was calculated for comparative analysis of drought tolerance.[Results]The results showed that:(1)Compared with diploid,the primary trisomy plant exhibited smaller stature and weaker growth,especially the No.6 primary trisomy displaying the most noticeable difference,and the edge undulation of the petals of the No.7 primary trisomy was not obvious.The pollen sterility rate for No.7 primary trisomy was 16.3％,while for No.6 primary trisomy,it was 41.6％,far higher than the diploid's 8.5％.(2)The meiosis of primary trisomy was generally nor-mal,following the typical pattern of diploid plant meiosis.(3)During drought stress treatment,chlorophyll degradation in both primary triploids was faster than in the diploid.the degradation rate of chlorophyll of the two primary trisomies was greater than that of diploid.No.6 primary trisomy showed the most significant increase in relative conductivity and malondialdehyde con-tent,followed by No.7 primary trisomy,with the diploid exhibiting the lowest.Superoxide dismutase and peroxidase activity showed a gradual increase,with the diploid exhibiting the most significant increase in enzyme activity,followed by No.7 pri-mary trisomy,and No.6 primary trisomy showing the least increase.The ranking for drought tolerance calculated by the aver-age membership function value was diploid＞No.7 primary trisomy＞No.6 primary trisomy.[Conclusion]Studies indicated that utilizing the backcross between triploids and diploid was an effective way for creating petunia primary trisomy.Compared to the diploid,the primary trisomy showed reduced growth,increased pollen sterility,and decreased drought stress tolerance.Notably,the No.6 primary trisomy showed more significant changes compared to the No.7 primary trisomy.
[Objective]This study aimed to explore an efficient and energy-saving extraction method for extracting polysaccha-rides from chili peppers and investigate the impact of different chili pepper germplasm resources on their polysaccharide content.The study screened out the optimal ultrasonic extraction process for pepper polysaccharides and measured the polysaccharide content in the fruits of 162 different pepper germplasm resources based on this process.[Methods]The study assessed the influ-ence of solid-liquid ratio,ultrasonic time,and ultrasonic temperature on the extraction rate and yield of pepper polysaccharides.The response surface methodology was employed to optimize the ultrasonic extraction process for chili pepper polysaccharides.Subsequently,the optimized extraction process was used to determine the polysaccharide content in the fruits of 162 different germplasm resources for comparative analysis,aiming to identify pepper germplasms rich in polysaccharides.[Results]The op-timal conditions for ultrasonic extraction of chili pepper polysaccharides were found to be a solid-liquid ratio of 1:24,ultrasonic time of 54 mins,and ultrasonic temperature of 61 ℃,yielding a polysaccharides extraction rate of 4.61％±0.26％based on practical experiments.Under these optimal conditions,the polysaccharide content in the fruits of 162 pepper germplasm resourc-es ranged from 2.22％±0.15％to 7.21％±0.70％,with an overall average content of 4.00％±0.58％.Significant differ-ences in polysaccharide content were observed among different pepper germplasms,with germplasm 002 showing the highest polysaccharide content and the germplasm 166 the lowest.Based on polysaccharide content,the 162 pepper germplasm re-sources were categorized into five groups:extremely high(P1),high(P2),moderate(P3),low(P4),and extremely low(P5)types.The analysis revealed that the lantern-shaped pepper germplasm exhibited the highest average polysaccharide con-tent,and among the seven germplasms in groups P1 and P2,all except CM12 were lantern-shaped chili peppers.[Conclusion]This study established the optimal ultrasonic extraction process for pepper polysaccharides and determined the polysaccharide content in the fruits of 162 pepper germplasm resources based on this process.It was found that lantern shaped peppers had a relatively high average polysaccharide content.These research results can serve as a reference for the development and applica-tion of chili pepper germplasm resources rich in polysaccharides.
[Objective]The aim of this study was to identify sorghum aphid-resistant germplasm resources through field inocula-tion.The goal was to reveal the metabolites,metabolic pathways,and functional differences of aphid-resistant materials through physiological metabolomics analysis.Additionally,the research sought to enhance sorghum parental materials through breeding practice to facilitate the development of sorghum variety with resistance to aphid.[Method]In the summer of 2022,22 breeding materials were field-inoculated and evaluated,resulting in the identification of one highly resistant and one highly sus-ceptible material.During the winter jointing stage of 2022,samples were collected for physiological metabolomics determina-tion,three days post-inoculation.[Result]Significant differences were observed in the susceptibility of the 22 materials after in-oculation.Among these,three high-resistant materials and two high-susceptible materials were identified.Specifically,the high-susceptible maintainer line,LB36(aphid ratio 1.78),and the high-resistant maintainer line,LB34(aphid ratio 0.12),were selected for further investigation.The results of physiological metabolomics analysis revealed 140 differential metabolites in the comparison of the resistant and susceptible materials(K1 vs G1)before inoculation,and 181 differential metabolites after inoculation(K2 vs G2).Subsequent comparisons highlighted 17 significantly up-regulated and 24 significantly down-regulated differential metabolites in the comparison of K1 vs K2,and 51 significantly up-regulated and 42 significantly down-regulated dif-ferential metabolites in the highly susceptible materials(G1 vs G2).Both resistant and susceptible materials were enriched in two KEGG metabolic pathways related to of phenylpropanoid biosynthesis and phenylpropanoid compound biosynthesis.In ad-dition,the differential metabolite L-glutamine exhibited an up-regulation trend in high-resistant materials,contrasting with its down-regulation after inoculation in high-susceptible materials.[Conclusion]Among the 22 parental lines,three were identified as high-resistant materials,including one maintainer line(LB34)and two restorer lines(NK1 and LNR-4).Two materials ex-hibited high susceptibility,with one maintainer line(LB36)and one restorer line(LTR168).The enrichment of LB34 in phen-ylpropanoid biosynthesis and phenylpropanoid compound biosynthesis pathways,reflected the crucial role of these pathways in plant growth and resistance to biotic or abiotic stress.The differential metabolites L-glutamine demonstrated significant contri-bution by promoting energy metabolism,enhancing the antioxidant enzyme activity of plants,ultimately leading to resistance against aphid infestation.
[Objective]The aim of the study was to clarify the chemical substances emitted by Larix principis-rupprechtii Mayr,and to provide a reference for identifying chemicals that might attract or repel insects of L.principis-rupprechtii.[Methods]The dynamic headspace adsorption method was used to extract volatiles from branches of L.principis-rupprechtii under three different conditions,including healthy,mechanically damaged,and insect damaged.The volatiles were identified and analyzed using gas chromatography-mass spectrometry(GC-MS)technology.[Results]The results showed that a total of 59 volatile compounds were identified under three conditions.The branches of L.principis-rupprechtii released 52,53 and 53 kinds of volatiles under three treatment conditions of health,pest,and mechanical damage,respectively.These compounds en-compassed ten categories:aromatic hydrocarbons,ketones,alcohols,terpenes,esters,aldehydes,acids,phenols,alkanes,and ethers.Four categories showed higher levels,with alkanes being the most abundant,followed by ketones,terpenes,and aldehydes,while the remaining six categories exhibited lower levels.There were three unique volatile compounds under the healthy condition,such as heptane,1,3,5-triethylbenzene,and n-heptacosane.Under insect-infested conditions,three unique volatiles were detected,including 3-carene,n-hexane,and n-octadecane.No specific volatiles were detected under the mechan-ical damage condition.Forty-five compounds were shared across all three conditions,with four compounds exhibiting higher contents:4-ethylbenzaldehyde,3-ethylacetophenone,4-ethylacetophenone,and β-pinene and(+)-pinene.Five compounds displayed significant differences,namely(+)-α-pinene,β-pinene,cetylaldehyde,2,2'-methylene bis-(4-methyl-6-tert-butyl-phenol),and 2,6,10-trimethyl-dodecane.Among the major components,(+)-α-pinene,β-pinene,and 2,2'-methylene bis-(4-methyl-6-tert-butylphenol)showed significantly higher concentrations.Notable,the(+)-α-pinene and β-pinene levels under mechanically injury and insect infestation conditions were significantly higher than those under the healthy condition(P＜0.05).[Conclusion]The branches of L.principis-rupprechtii exhibited variations in alkanes and terpenes under three different treat-ments as health,insect damaged,and mechanically damaged states.The relative content of alkanes in the mechanical damaged state was approximately 10％higher than that in health and insect damaged state,while the terpene content was about 15％low-er.
[Objective]The purpose of this paper aimed to reveal the soil water holding capacity and influencing factors of different reclaimed vegetation in the dump soil yards,and to provide a scientific basis for ecological restoration in soil dumping areas.[Method]Three types of reclaimed grass,Elymus dahuricus Turcz.,Astragalus adsurgens,and Leymus chinensis(Trin.ex Bunge)Tzvelev,were selected as the research objects.Changes in soil physical properties,such as soil porosity,water holding capacity and aggregates in 0～40 cm soil layer,were studied.The influencing factors of soil water holding capacity were ana-lyzed,and the principal component analysis method was used to comprehensively evaluate the soil water retention capacity of dif-ferent reclaimed vegetation in the soil dumping area.[Results]With the increase in soil depth,the soil bulk density of the three sample plots in the soil dumping area initially increased and then decreased with the increase of soil depth,showing differences between different soil layers,indicating that reclaimed vegetation had different effects on the soil bulk density in the soil dumping area.The average soil bulk density of the 0～40 cm soil layer was ranked as Leymus chinensis(Trin.ex Bunge)＞Elymus dah-uricus Turcz.＞Astragalus adsurgens,with values of 1.38,1.37,and 1.33 g·cm-3,respectively.Soil capillary porosity showed the opposite trend.The predominant aggregates were micro-aggregates(particle size＜0.25 mm),ranging between 70.48％and 83.10％,with the content of macro-aggregates(particle size＞5 mm)only between 1.46％to 7.78％.Soil aggre-gate stability was relatively poor,indicated by the low values of aggregate stability indices K,MWD,and GWD.The maxi-mum water holding capacity of Elymus dahuricus Turcz.,Astragalus adsurgens,and Leymus chinensis(Trin.ex Bunge)Tzvelev in 0～40 cm soil layer was 667.21,664,and 666.56 g·kg-1,respectively.The maximum water holding capacity,field water capacity,and capillary water capacity of Elymus dahuricus Turcz were significantly higher than those of Astragalus adsur-gens and Leymus chinensis(Trin.ex Bunge)Tzvelev(P＜0.05).Factors affecting the soil water retention capacity in the soil dumping yard were mainly soil bulk density,porosity,and the content of 2～5 mm soil water stable aggregates.The soil water holding capacities of different vegetation types were evaluated by principal component analysis,and the results indicated that 14 evaluation indicators could be reduced to four principal components.The ranking of scores for each principal component varied,and the comprehensive score of soil water holding capacity was Elymus dahuricus Turcz.＞Astragalus adsurgens＞Leymus chi-nensis(Trin.ex Bunge)Tzvelev,with the comprehensive score of Elymus dahuricus Turcz.significantly higher than that of As-tragalus adsurgens and Leymus chinensis(Trin.ex Bunge)Tzvelev.[Conclusion]Considering soil porosity structure,aggregate stability,and water holding capacity from multiple perspectives,Elymus dahuricus Turcz.is optimal for soil improvement and water conservation effects in soil dumping area,followed by Astragalus adsurgens and Leymus chinensis(Trin.ex Bunge)Tzvelev.
[Objective]The purpose of this study was to explore an optimal liquid medium most suitable for Bacillus velezensis fermentation.[Method]By conducting surveys among farmers,methods for the preparation of homemade microbial fermenta-tion solution were collected and screened.Eventually,the study designed four treatments,including millet porridge with brown sugar medium(T2),rice washing water with brown sugar medium(T3),brown sugar medium(T4),and LB medium as the control treatment(T1).The above-mentioned media were prepared by inoculating 2％Bacillus velezensis strain culture mother liquor and applied through seedling tray irrigation.Research was conducted on three aspects:the growth of cucumber seed-lings,changes in nutrient content in the substrate,and the types of pathogenic microorganisms.[Result]The results showed that T1,T2,and T3 treatments displayed significant improvement in four indicators,including plant height,stem thickness,aboveground fresh weight,and aboveground dry weight compared to the CK treatment,with no significant difference among the three treatments.Regarding leaf area and chlorophyll,T1 and T3 treatments performed the best,with no significant difference between the two.T4 treatment showed no significant difference in plant height,leaf area,aboveground fresh weight,and aboveground dry weight compared to CK treatment,but significantly outperformed in stem thickness.However,in chlorophyll content,T4 treatment significantly decreased compared to CK treatment.Both T2 and T4 treatments significantly outper-formed the CK treatment in total root length and total root area,without significant differences between T1 and T3 treatments.Only T3 treatment significantly outperformed the CK treatment in underground fresh weight and underground dry weight,with the other fermentation treatments showing no significant difference relative to CK treatment in these two indicators.The com-prehensive evaluation of cucumber seedling growth using the affiliation function method and the strength seedling index revealed that T3 treatment had the most prominent growth-promoting effect on cucumber seedlings.Regarding the changes in nutrient content in the substrate after seedling establishment,except for mineral nitrogen content,T3 treatment significantly decreased in effective phosphorus,quick-acting potassium,and organic matter content compared to other treatments.Through fluores-cence quantitative analysis of Fusarium spp.in the substrates after fermentation liquid treatment,the Fusarium spp.copy num-bers were significantly lower than those in the CK treatment.[Conclusion]The medium prepared with 10 L of rice washing wa-ter combined with 20 g of brown sugar was the most suitable for preparing B.velezensis fermentation broth.
[Objective]Tetrastigma hemsleyanum Diels et Gilg is a unique and rare medicinal plant in China,which contains abundant antioxidant and antibacterial components.This study mainly aimed to explore the antioxidant and antibacterial activi-ties of different extracts from T.hemsleyanum tuber roots,providing a sufficient theoretical basis for the development of phar-maceutical and industrial products.[Methods]The antioxidant and antibacterial activities of different extracts from T.hemsleya-num tuber roots using different solvents,including N-butanol,ethyl acetate,petroleum ether,and water,were measured using DPPH,ABTS+·,FRAP,and a two-fold dilution method.[Results](1)All four different extracts from T.hemsleyanum tu-ber roots demonstrated both antioxidant and antibacterial activities,which increased with the concentration of extracts;(2)The N-butanol extract exhibited the most potent antioxidant effects(IC50DPPH·=3.68±0.56 mg·L-1,IC50ABTS+.=11.57±1.66 mg·L-1),nearly equivalent to the antioxidant capacity of L-ascorbic acid.Next in potency was the ethyl acetate extract(IC50DPPH.=6.13± 0.77 mg·L-1,IC50ABTS+.=16.58±1.71 6 mg·L-1),while the petroleum ether extract and water extract showed significantly weaker antioxidant effects(P＜0.01).(3)There were differences in the antibacterial activities of the four different extracts from T.hemsleyanum tuber roots against different bacteria strains.The inhibitory and bactericidal effects of the four different extracts were ranked as follows:n-butanol＞ethyl acetate＞petroleum ether＞water.The antibacterial activity of N-butanol extract were as follows:MIC(E.coli)=0.31 g·L-1,MBC(E.coli)=0.63 g·L-1,MIC(B.subtilis)=1.25 g·L-1,MBC(B.subtilis)=1.25 g·L-1,MIC(E.faecalis)=0.63 g·L-1,MBC(E.faecalis)=0.63 g·L-1,MIC(P.aeruginosa)=0.63 g·L-1,MBC(P.aeru-ginosa)=0.63 g·L-1 and MIC(S.aureus)=0.63 g·L-1,MBC(S.aureus)=1.25 g·L-1.None of the extracts from T.hemsleyan-um tuber roots showed significant antibacterial activity against Canadida.albicans.[Conclusion]The findings indicated that T.hemsleyanum tuber roots exhibit strong antioxidant capacity and broad-spectrum antibacterial effects.The active substances mainly enrich in N-butanol extracted fraction,followed by the ethyl acetate extracted fraction.
[Objective]The assessment of germplasm genetic diversity can guide the selection of superior complementary parent lines in resource research and breeding,facilitating the enhancement of the exchange and accumulation of superior genes,thus improving the efficiency of breeding new varieties.[Methods]In this study,45 wheat millet germplasms(25 japonica varieties and 20 waxy varieties)were selected from different provinces in China.Coefficient of variation analysis,correlation analysis,principal component analysis,and cluster analysis were used to comprehensively assess seven phenotypic traits,evaluate the ge-netic differences in agronomic traits,and screen for excellent trait resources.Under the same environmental conditions,the study compared the yield differences of various broom corn millet varieties in typical sandy loam soil and saline-alkali soil while analyzing their saline-alkali tolerance.[Results]Significant genetic differences in agronomic traits were evident,displaying rich diversity.Plant height,panicle length,grain weight per panicle,1000-grain weight per panicle,and growth period exhibited considerable variation.The principal component analysis indicated that panicle weight,panicle weight,plant height,panicle length,1000-grain weight,and growth period could serve as primary indicators for phenotypic identification of broom corn mil-let.Systematic cluster analysis categorized broom corn millet resources into three groups.Group Ⅰ primarily consisted of japoni-ca varieties,group Ⅲ mainly consisted of glutinous varieties,and group Ⅱ consisted of only two varieties-Nymme No.1 and No.7-characterized mainly by their extended growth period.The comparative analysis of adaptability to saline-alkali soil showed that apart from 10 varieties displaying moderate tolerance,the remaining varieties demonstrated weak or very weak tol-erance to saline-alkali conditions.[Conclusion]Based on the comprehensive evaluation of seven main agronomic characteristics and saline-alkali tolerance,varieties with favorable traits suitable for introduction in North Shanxi and saline-alkali land were se-lected,including Yimi 5,Gumi 21,Ningmi 10,and Ningmi 9.
[Objective]This study intended to use rapeseed cake to supplement nitrogen and explore the nitrogen utilization dur-ing the preparation of straw-based substrate blocks and the process of seedling cultivation.[Method]Four different proportions of rapeseed cakes were added during the preparation of straw-based seedling substrate blocks,including CK with 100％straw,T1 with 5％rapeseed cake+95％straw,T2 with 10％rapeseed cake+90％straw,and T3 with 15％rapeseed cake+85％straw.Seedlings were cultivated using these blocks,and the differences in nitrogen utilization during the formation and rice seedling cultivation process of straw-based blocks with different proportions of added rapeseed cake were compared.[Result]Compared to CK,the plant height of T1,T2,and T3 increased by 14.7％,17.1％,and 22.7％,respectively.Stem diame-ter and the fresh weight of 100 plants in T1 and T3 increased by 0.7％,4.8％and 3.6％,17.0％,respectively,compared to CK.T3 exhibited the highest total nitrogen content,total carbon content,and ammonium nitrogen content in the substrate blocks,showing a respective increase of 17.3％and 84.4％in total carbon and ammonium nitrogen content compared to CK.Nitrate nitrogen content was the highest in T1 treatment,significantly higher than that in CK,with an 89.7％increase.The to-tal nitrogen content and nitrogen accumulation in seedlings were highest in T3,with the total nitrogen content significantly high-er than CK,showing a 17.2％increase.Both the amount of nitrogen loss and nitrogen loss rate were reduced in treatments with added rapeseed cake compared to CK.Specifically,the nitrogen loss amount and nitrogen loss rate in T3 treatments were significantly lower than in other treatments,showing reductions of 24.6％and 23.3％compared to CK,6.1％and 16.0％compared to T1,and 7.0％and 14.6％compared to T2.[Conclusion]The addition of rapeseed cake during the preparation of straw-based substrate blocks significantly reduced the nitrogen loss and enhanced the biological characteristics of seedlings culti-vated with the straw-based substrate block.Among these treatments,straw-based blocks with 15％added rapeseed cake pro-duced seedlings with optimal characteristics such as plant height and stem thickness,with a significantly lower nitrogen loss rate compared to other treatments.
[Objective]In order to explore the benefits of intercropping grass crops with legumes,this study focused on the sor-ghum-peanut intercropping system.The objective was to determine the optimal row ratio for sorghum-peanut intercropping and to reveal the mechanism contributing to increased yield.[Methods]This study spanned two consecutive years,from 2021 to 2022,using sorghum variety Liaonuo 11 and peanut Jinhua 15 as the test materials.Intercropping row ratios were set at 4:4 and 8:4,with sole cropping as the control.The study aimed to determine and analyze differences in biotic traits,light energy use characteristics,material production capacity,and yields of sorghum and peanut across various intercropping row ratios.[Re-sults]Over the two-year experimental period,sorghum and peanut intercropping significantly improved sorghum's population traits,photosynthesis,and biomass production capacity.Notably,this was evident in reduced plant height,increased stem di-ameter,dry matter of per plant,and yield.The biotic traits of sorghum were most favorable in the 4:4 sorghum-peanut inter cropping,where plant height decreased by 4.56％to 6.21％,and stem thickness increased by 5.95％to 11.43％.The high-est yields reached 11 202.34 kg·hm-2(2021)and 11 790.64 kg·hm-2(2022),marking a 32.40％and 34.14％increase com-pared to monocropping,with a 3.39％to 10.59％rise in thousand kernel weight and a 5.51％increase in spike weight.Addi-tionally,the highest dry matter accumulation of 377.59 g·plant-1 per plant was recorded,marking a 22.86％increase;The net photosynthetic rate was noticed an 11.81％to 13.35％increase,transpiration rate increased by 18.58％to 53.27％,stomatal conductance increased by 25.57％to 53.96％,inter-cellular carbon dioxide concentration decreased by 15.30％,sorghum seed light energy utilization increased by 31.25％to 34.48％,and biological yield light energy utilization increased by 22.65％(2022).[Conclusion]Sorghum and peanut intercropping demonstrated high land use efficiency,with sorghum as the predomi-nant crop in this system.Optimal intercropping row ratios improved sorghum canopy structural characteristics,increased photo-synthetic capacity,and light energy utilization,establishing a solid foundation for dry matter accumulation and yield.The 4:4 in-tercropping ratios showed the best overall performance across the studied parameters.
[目的]本文旨在明确红棕象甲幼虫对吡虫啉的敏感性及其中毒后的行为学反应.[方法]采用经口注射法,研究了吡虫啉处理对红棕象甲高龄幼虫的致死中剂量和致死中时间,并分析了经药剂处理后红棕象甲的形态学变化.[结果](1)在供试剂量下,吡虫啉对红棕象甲幼虫的致死中时间(LT50)无显著差异,随供试时间延长,致死中剂量(LD50)呈现降低趋势,其中在处理后96 h的LD50为每头0.43 μg.(2)在每头25 μg剂量吡虫啉处理后10～11 min,红棕象甲幼虫丧失活动能力,而在每头62.5～500 μg剂量处理中,试虫丧失活动能力的时长介于1～30 min.(3)吡虫啉处理后红棕象甲幼虫的毒理学症状随处理时间延长依次主要表现为:虫体蜷缩、皱缩、抖动、口器持续大张、体壁松软、体壁僵硬、平衡感缺失后恢复等,其中抖动、口器持续大张、体壁僵硬等现象随时间的延长会反复交替出现.除口器持续大张状态外,其余各状态的出现频率的最高值和最低值均在处理后48 h出现.(4)高剂量下个别试虫会出现内容物崩出的现象,且高剂量会更快的完成各毒理学症状的表现.(5)在经过重新喂食后,部分中毒反应出现缓解,其中以口器持续大张状态在喂食后24 h缓解最为明显.[结论]吡虫啉对红棕象甲的LT50与供试剂量大小无明显相关性.经吡虫啉处理后,红棕象甲幼虫出现明显的中毒反应,同时在经过重新饲喂取食后,部分症状会有所缓解.
[目的]针对自然场景下无人机拍摄的图像中鼠洞目标占比小,与地物高度融合且容易受阴影等各类因素影响,导致误识别率高的情况,需要对目标检测算法进行改进,以提高鼠洞定位精度.[方法]以YOLOv5s为基础算法进行优化改进,在Backbone主干网络的C3模块融合轻量ECA注意力机制模块,从通道方面更好关注特征信息,降低漏检率;在特征金字塔FPN中引入转置卷积学习最佳上采样方法,恢复卷积运算中丢失的有用信息;用SIoU替换CIoU损失函数来有效减少冗余框,同时加快预测框的收敛和回归.其次,做消融实验来验证3种改进策略的有效性并对比模型改进前后在不同场景下的识别情况.[结果]改进的YOLOv5s比原始模型的P、R和mAP分别提高了3.3%、3.7%和3.5%,FPS达到了56.7,且在特殊场景下无漏检、错检的情况,可以保证鼠洞检测的准确性和实时性.对比其它算法在平均检测精度、体积和速度上都较有优势.[结论]本文改进的算法能满足在复杂场景下的鼠洞检测,实现精确定位,为鼠害监测提供鼠洞检测方面的支撑.
[目的]随着富硒功能农业的发展及国民膳食结构的改变,以谷子为代表的杂粮成为富硒农作物研究的热点,明确不同土施硒肥位置对谷子生理特性及硒积累的影响可为谷子富硒肥精准施用技术提供理论支持.[方法]以"张杂谷13号"为材料,通过种肥同播的方式,采用单因素完全随机设计,在距离谷子植株水平距离设置5和10 cm两个水平、距离土表垂直深度设置5、10和15 cm三个水平,共计6个施用富硒有机肥位置处理,对谷子成熟期农艺性状、不同器官干物质量、产量及其构成因素、硒含量和硒积累量进行测定.[结果]在距离谷子植株水平距离10 cm、距离土表垂直深度 10 cm处理下,谷子株高、旗叶宽度、叶片干物质量、籽粒干物质量均达最大值,分别为 120.51 cm、3.24 cm、4.14 g、19.09 g,且相比其他处理的增幅范围分别为 15.96％～23.06％、9.83％～23.66％、6.43％～245.00％、1.49％～135.97％;籽粒硒含量及硒积累量也达到最大值,分别为0.77 mg·kg-1和14.75 μg·株-1,显著高于其它处理,且相比其他处理的增幅范围分别为18.46％～60.42％和44.89％～219.96％.施用富硒有机肥不同处理下,谷子籽粒所含硒元素均以硒代蛋氨酸和硒代胱氨酸等有机态硒存在.[结论]利用隶属函数法综合分析可得,在距离谷子植株水平距离10 cm、距离土表垂直深度10 cm处施用硒肥为"张杂谷13号"土施富硒有机肥的适宜位置.
[目的]冀北坝上地区燕麦产量较低且年际间波动剧烈,探究品种多样性对燕麦种子产量稳定性的影响,对保证燕麦高产和稳产具有重要意义.[方法]选择坝莜3号、蒙燕1号、坝燕6号、甜燕麦、白燕18号和KONA(美国)6个品种为试验材料,研究2017-2019年不同品种的生育期和产量变化,并揭示燕麦产量变异的气象决定因子.[结果]不同燕麦品种生育期在78～99 d之间,其中坝莜3号生育期最长.同一品种生育期年际间变异较高.2017年、2018年和2019年 6个品种的产量分别为 2872.51～5860.55 kg·hm-2、3194.70～4841.50 kg·hm-2和3117.50～5193.75 kg·hm-2,年际间变异为11.7～29.2％.6个品种的平均产量分别为4424.61、4158.46和3865.71 kg·hm-2,干旱年份(2019年)品种多样性的产量优势更加明显.品种多样性显著降低年际间产量的变异,6个品种平均产量的年际间变异率仅为6.7％.出苗-孕穗期降水量(PE-B)、抽穗-开花期降水量(PB-F)、开花-乳熟期最低温度(TminF-MR)和孕穗-抽穗期总辐射(SB-H)4个因子决定冀北坝上地区燕麦产量变异的70％.[结论]品种多样性提高冀北坝上地区燕麦种子产量和年际间产量稳定性,并且品种多样性的产量优势在干旱年份更加明显.
[目的]本文旨在探讨云南松苗木生物量特征与苗木质量指数间相对生长关系.[方法]以3年生云南松苗木为研究材料,采用整株收获法测定云南松苗木各构件生物量,以苗木质量指数作为苗木个体大小的评价,分析其生物量的分配特征.[结果]云南松苗木生物量分配存在较大的差异,且各构件间的分配也存在较大的波动,其中以叶、茎的分配占比较大.从生物量投资来看,在单株水平和构件水平上云南松苗木生物量积累与苗木质量指数均呈极显著正相关关系(P<0.01),表现为线性函数形式增长.从生物量分配格局来看,生物量分配与苗木质量指数间呈幂函数形式的异速生长关系.进一步分析表明,在单株水平上,苗木质量指数增加,生物量向根分配降低,而向地上部分分配增加.在构件水平上,苗木质量指数增加,根的分配中主根相对减少而侧根增加,地上部分向叶的分配增加而向茎分配减少.[结论]云南松苗木生物量分配与苗木质量指数间关系密切,苗木通过各器官间生物量投资差异来调整分配策略.
[目的]梨小食心虫是世界性的果树害虫之一,世代重叠率高,其幼虫危害最为严重,因其有钻蛀性不易被发现和防治,需要确定成虫的为害动态再根据测报理论指导Ⅰ龄害虫的防治.目前,梨小食心虫害虫的监测主要是通过水盆法诱集并人工对成虫进行计数,但是,人工计数调查后推测梨小食心虫种群动态,不能及时获取种群信息并进行防控,将会带来不可估量的经济损失.因此,探索精准、快速监测梨小食心虫种群动态变化的智能化技术,为其有效防控,实现果品高产优产提供新思路成为了亟待解决的问题.[方法]本文采用Keras?YOLOv3目标检测法识别梨小食心虫并计数,将已采集的梨小食心虫图像经过Keras中数据增强功能进行模型输入等处理,提高梨小食心虫图像辨识、定位和计数的精准度和效率.[结果]自然条件下,Keras?YOLOv3网络模型对梨小食心虫的检测速度为每张0.042 s,检测平均精度mAP值为88.2％,计数精确率为94.5％,较传统YOLOv3模型依次分别提高了10.6％、7.1％、12.0％.在多种害虫并发时,本模型训练的网络环境复杂度欠缺且害虫种类少,梨小食心虫检测的平均精度mAP降至79.98％,计数准确率降至83％.[结论]该网络模型可以方便快捷地检测梨小食心虫以及计数,为梨小食心虫害虫种群监测防治智能化提供了新思路,扩大了计算机视觉中的目标检测模型的适用范围,实现了田间小型昆虫的检测识别,为其提供了参考依据.
[目的]柠条种子小蜂(Bruchophagus neocaraganae)是我国林业危险性有害生物.本研究将明确柠条种子小蜂对3种不同处理(健康、机械损伤和受柠条种子小蜂危害)中间锦鸡儿(Caragana liouana)的行为反应,测定不同处理的植物挥发物组分,以及挥发物单体对柠条种子小蜂的作用.[方法]利用Y型嗅觉仪测定柠条种子小蜂成虫对3种不同处理的中间锦鸡儿的行为选择,采用动态顶空吸附法和气相色谱—质谱联用仪(GC-MS),收集并分析健康、机械损伤和受柠条种子小蜂危害后挥发物组分及相对含量的变化,并进行主成分分析.[结果]健康中间锦鸡儿对柠条种子小蜂成虫具有显著的诱引作用,受虫害的中间锦鸡儿对柠条种子小蜂成虫具有显著的趋避作用.不同处理的中间锦鸡儿挥发物中共含有35种化学成分,主要为萜烯类化合物,另外还有少量酯类、醇类、酮类、醛类、烷烃和烯烃化合物.与健康植株相比,受虫害的中间锦鸡儿挥发物中新出现了3-蒈烯、α-蒎烯、α-香柠檬、β-波旁烯等物质,健康植株挥发物中检测到的水杨酸甲酯、顺-3-己烯醇和环癸醇并未在虫害植株中检测到.与健康植株相比,受机械损伤后的中间锦鸡儿挥发物中新出现了α-香柠檬、γ-戊内酯、对乙基苯甲醛等物质.健康植株挥发物中检测到的反-3-己烯醇、罗勒烯和水杨酸甲酯并未在机械损伤植株中检测到.在行为选择试验中,反-3-己烯醇、柠檬烯和水杨酸甲酯对柠条种子小蜂产生吸引作用,3-蒈烯、β-石竹烯和月桂烯对柠条种子小蜂产生趋避作用,柠条种子小蜂对乙基苯甲醛和γ-戊内酯无明显的选择行为.[结论]柠条种子小蜂的危害以及机械损伤均能改变中间锦鸡儿挥发物组分,反-3-己烯醇、柠檬烯和水杨酸甲酯对柠条种子小蜂产生吸引作用,3-蒈烯、β-石竹烯和月桂烯对柠条种子小蜂产生趋避作用,可以为开发该害虫的植物源引诱剂或趋避剂奠定基础.
