[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.
