Genome-wide identification,characterization and functional prediction of the SRS gene family in sesame(Sesamum indicum L.)

Sesame(Sesamum indicum L.)is an ancient oilseed crop of the Pedaliaceae family with high oil content and potential health benefits.SHI RELATED SEQUENCE(SRS)proteins are the transcription factors(TFs)specific to plants that contain RING-like zinc finger domain and are associated with the regulation of several physiological and biochemical processes.They also play vital roles in plant growth and development such as root formation,leaf development,floral development,hormone biosynthesis,signal transduction,and biotic and abiotic stress responses.Nevertheless,the SRS gene family was not reported in sesame yet.In this study,identification,molecular characterization,phylogenetic relationship,cis-acting regulatory elements,protein-protein interaction,syntenic relationship,duplication events and expression pattern of SRS genes were analyzed in S.indicum.We identified total six SiSRS genes on seven different linkage groups in the S.indicum genome by comparing with the other species,including the model plant Arabidopsis thaliana.The SiSRS genes showed variation in their structure like2–5 exons and 1–4 introns.Like other species,SiSRS proteins also contained‘RING-like zinc finger'and‘LRP1'domains.Then,the SiSRS genes were clustered into subclasses via phylogenetic analysis with proteins of S.indicum,A.thaliana,and some other plant species.The cis-acting regulatory elements analysis revealed that the promoter region of SiSRS4(SIN_1011561)showed the highest 13 and 16 elements for light-and phytohormone-responses whereas,SiSRS1(SIN_1015187)showed the highest 15 elements for stress-response.The ABREs,or ABA-responsive elements,were found in a maximum of 8 copies in the SiSRS3(SIN 1009100).Moreover,the available RNA-seq based expression of SiSRS genes revealed variation in expression patterns between stress-treated and non-treated samples,especially in drought and salinity conditions in.S.indicum.Two SiSRS genes like SiSRS1(SIN_1015187)and SiSRS5(SIN_1021065),also exhibited variable expression patterns between control vs PEG-treated sesame root samples and three SiSRS genes,including SiSRS1(SIN_1015187),SiSRS2(SIN_1003328)and SiSRS5(SIN_1021065)were responsive to salinity treatments.The present outcomes will encourage more research into the gene expression and functionality analysis of SiSRS genes in S.indicum and other related species.

Production and achievements of Sesamum indicum industry in the world:Past and current state

Sesame production is important in agriculture,food industry,and the crop diversity due to its rich nutritional profile and health benefits.Despite its significant value,sesame is still an orphan crop that has received little scientific attention,resulting in low yield compared to other major oilseed crops.This review offers a comprehensive overview of the present state of production,knowledge,and research advancements concerning Sesamum indicum on a global scale.The FAOSTAT database was extensively used to examine the global trends from 1961 to 2021.In the past 60 years,global sesame production has substantially increased,with Asia and Africa being the primary producers.The integration of omics technologies and biotechnological interventions has revolutionized our understanding of the genetic basis of sesame,enhanced productivity,invigorated stress resilience,and improved seed quality.High-throughput sequencing methods such as RNA-seq,RAD-seq,SLAF-seq,and GBS technology are used in various studies,linkage mapping,and identification of trait-associated markers.Fine linkage maps,and multi-omics studies such as genomics,proteomics,transcriptomics,and metabolomics have been employed in sesame research for gene and QTL mapping.Proteins and metabolic pathways related to oil content,yield,and stress tolerance were reported.Genes and QTLs related to yield and its components,drought,salt,and osmotic stress tolerance were discovered.Candidate genes associated with capsule shattering and seed shattering were recently revealed.For more achievement in sesame,it is important to enhance sesame production efficiency through mechanization,advanced agricultural practices,and knowledge dissemination to farmers.MAS and multi-omics integration should be particularly reinforced.The advancements in sesame production present a significant and promising opportunity for farmers,governments,and stakeholders in the agricultural sector.

Antioxidant lignans sesamin and sesamolin in sesame(Sesamum indicum L.):a comprehensive review and future prospects

Sesame(Sesamum indicum L.)is a significantly lucrative cash crop for millions of small-holder farmers.Its seeds are an important source of a highly appreciated vegetable oil globally and two clinically essential antioxidant lignans,sesamin and sesamolin.Accordingly,many countries import millions of tons of sesame seed every year.The demand for lignan-rich sesame seeds has been increasing in recent years due to the continuous discovery of several pharmacological attributes of sesamin and sesamolin.To meet this demand,the sesame breeder’s primary objective is to release sesame cultivars that are enriched in oil and lignans.Thus,it is necessary to summarize the information related to the sesamin and sesamolin contents in sesame in order to promote the joint efforts of specialized research teams on this important oilseed crop.In this article,we present the current knowledge on the sesamin and sesamolin contents in S.indicum L.with respect to the updated biosynthesis pathway,associated markers,governing loci,available variability in sesame germplasm,the in planta potential roles of these compounds in sesame,and the newly discovered pharmacological attributes.In addition,we propose and discuss some required studies that might facilitate genomics-assisted breeding of high lignan content sesame varieties.

Deletion of a 1,049 bp sequence from the 5′UTR upstream of the SiHEC3 gene induces a seed non-shattering mutation in sesame

Sesame is a labor intensive crop with limited mechanized harvesting mainly due to the seed shattering(SS)trait.In this study,we performed a genetic analysis of the seed-shattering resistance(SR)trait with a SR sesame mutant 12M07.Unlike the SS type,the parenchyma cells in the abscission zone of the 12M07 mutant are arranged loosely but adhere to the seed coat.Inheritance analysis of six generations derived from 12M07(SR)×Xiangcheng Dazibai(SS)showed that the SR trait is recessive and controlled by a single gene pair.Association mapping of the F2population with 888,619 variants(single-nucleotide polymorphisms(SNPs)and insertion-deletion(InDels))and 31,884 structural variations(SVs)determined that only SV12002 in the 5′upstream region of gene Sindi0765000(named SiHEC3)in Chr.3 was significantly associated with the SR trait.SiHEC3 encodes the bHLH transcription factor.A 1,049 bp deletion occurred in the 5′UTR of Sihec3 in 12M07.SiHEC3 is mainly expressed in developing placental tissues,with the expression peaking in capsules at 45 days after pollination.A dual-luciferase reporter assay in tobacco confirmed that the promoter activity of Sihec3 was reduced because of the deletion of the 1,049 bp promoter sequence.Protein–protein interaction network analysis showed that HEC3 is co-expressed with nine key proteins,such as SHATTERPROOF1(SHP1)and SEEDSTICK(STK)which participate in the secondary wall biosynthesis of the abscission layer in plants.The findings of this study show the important function of Sihec3corresponding with the SR trait and supply the genetic information for breeding new varieties that are amenable to mechanized harvesting in sesame and other crops.

Sesamum indicum(sesame) enhances NK anti-cancer activity, modulates Th1/Th2 balance, and suppresses macrophage inflammatory response

Objective:To evaluate the potential immunomodulatory effects of an aqueous extract of Sesamum indicum seeds with regard to splenocyte proliferation,Th1/Th2 balance,macrophage function,and the cytotoxic activity of natural killer(NK)cells.Methods:Splenocyte proliferation was measured by[~3H]-thymidine incorporation.Griess assay was performed to evaluate the production of nitric oxide by macrophages.The levels of cytokines secreted by splenocytes and macrophages were measured by ELISA.JAM assay was performed to examine the cytotoxic activity of NK cells against YAC-1 tumor cells.Results:Sesamum indicum significantly enhanced splenocyte proliferation in a dose-dependent manner.Sesamum indicum also increased and suppressed the secretion of Th1 and Th2 cytokines,respectively,by splenocytes.The secretion of key pro-inflammatory mediators(IL-6,TNFα,and nitric oxide)by primary macrophages was significantly inhibited by Sesamum indicum.Moreover,Sesamum indicum increased the cytotoxic activity of NK cells against YAC-1 tumor cells.Conclusions:Sesamum indicum shows potent immunomodulatory,anti-inflammatory,and anti-cancer effects.Constituents of Sesamum indicum may be used as effective therapeutic agents in regulating immune reactions implicated in various infectious and noninfectious conditions including cancer.

Effect of Microclimatic Modification on Growth and Yield of Sesame （Sesamum indicum L.） in a Semi-Desert Region of Northern Sudan

An investigation was carried out in the semi- desert region of northern Sudan, during 2000, to study the influence of different micrometeorological parameters on growth and yield of sesame under alley cropping system. Sesame, cv. Kenana-2, was grown in 6-m wide alleys formed by 3 year old Acacia ampliceps and Acacia stenophylla. Air temperature, relative humidity, wind speed, solar energy and shade behaviour were measured throughout the growing season. Irrigation was measured by water meter and soil moisture by gravimetric sampling at depths of 15, 30, 45 and 60 cm, in alley cropping and control plots. Sesame was evaluated for growth and yield performance in southern, central and northern parts of each alley. The results showed substantial reduction in wind runs, solar radiation and air temperature, while relative humidity was increased under alley conditions. Soil moisture content, especially in the upper 045 cm soil depth, was much higher in alley cropped plots than in the control plots. A. stenophylla resulted in the highest saving of irrigation water and considerably increased （40%） sesame seed yield. In contrast, sesame seed yield was reduced by 46% under A. ampliceps-alley cropping. Competition for light and water were highly responsible for variation in sesame seed yield in the different zones of the alley. A. stenophylla tree is, therefore, recommended in an alley cropping system in the semi-desert region of northern Sudan for its superiority in optimizing radiation and saving of irrigation water.

Combined Effects of Compost,Supraxone and Lambda-Super on Soil Microbial Activity under Pluvial Cultivation of Sesame(Sesamum indicum L.)in Burkina Faso

Sesame cultivation is strategic for the economy of Burkina Faso. Indeed, after cotton, sesame is the second most important agricultural product for exportation. However, its production is limited by plant diseases and pest attacks. Facing this situation, large amounts of pesticides are used to boost productivity. But, these chemicals have a negative impact on soil fertility. In this instance, the effects of Supraxone and Lambda-super in the presence of compost on soil microbial activity under rainfed sesame cultivation in a peasant environment were studied. The experiment design was a block of Fisher (BCR) comparing the non-treated parcel (TNT) to the parcel amended only with compost (C) and to the parcel amended with compost and treated with the pesticides (C + P), respectively. Soil samples were taken at depths of 0 - 20 cm before sowing at 41st and 81st days after sowing. Respiratory activity and soil microbial biomass were monitored respectively by respirometric tests and by the fumigation-incubation method. The results show that the addition of compost into the soil with or without supraxone treatment and Lambda-super resulted in an increase in microbial biomass and soil respiratory quotient. These results show that the provision of compost in sufficient quantity corrects the inhibitory effect of soil biological activity by pesticides.

Assessing Genetic Variation and Relationships among a Mini Core Germplasm of Sesame (<i>Sesamum indicum</i>L.) Using Biochemical and RAPD Markers

Knowledge of genetic diversity is essential for any future varietal improvement program. Thus, the objective of this study is to contribute to a better knowledge of the genetic diversity within 15 sesame accessions, using biochemical markers and RAPD. The accessions are of various sources and seeds of different colors;color being an important feature in the sesame market. SDS-PAGE on protein extracts of sesame seeds revealed 31 protein markers, only 4 of which were polymorphic, indicating that this technique is not suitable for studying genetic diversity in S. indicum. The analyses on isoenzymatic extracts of esterase from sesame seedlings made it possible, to distinguish and classify the accessions into 2 major groups. RAPD analysis of genomic DNA using 10-mer primers revealed a high inter-accession genetic diversity. A total of 53 DNA markers, including 48 polymorphic, were produced. The coefficient of similarity between accessions ranged from 0.343 to 0.897. RAPD markers were found to be more suitable for studying genetic diversity within sesame germplasm than isozyme analyzes. Nevertheless, geographical distributions and seed colors are not related to the classes formed.

Genetic Diversity Assessment of Moroccan Sesame(Sesamum indicum L.)Populations Using Agro-morphological Traits

Genetic diversity of Moroccan sesame(Sesamum indicum L.)was analyzed for the first time using agro-morphological traits.Thirty-three sesame populations collected from Tadla region in Morocco were evaluated for 13 parameters in three contrasted environments,Afr-13,Afr-14 and Atj-14.Broad and significant variation among populations was observed only for three agro-morphologic traits,namely first capsule height(FCH),number of seeds per capsule(NSC)and thousand seeds weight(TSW).The respective overall averages were 71.82 cm(ranging from 65 cm to 77 cm),61.39(varying from 57 to 65)and 3.20 g(ranging from 3.0 g to 3.4 g).Environment had a highly significant effect on all studied parameters,except capsule size and oil content.The obtained mean values of parameters studied showed that environment Afr-14 was the most favorable for most of them,particularly seed yield(1.32 t/ha)and TSW(3.57 g).Significant and interesting correlations were observed between seed yield per plant(SYP)and other parameters.As relevant implication of this finding,number of capsules per plant(NCP)and NSC could be used as valuable selection criteria in sesame breeding program.However,limited and non-significant variation among sesame populations for most of parameters studied suggests that they are genetically very close and may be derived from a single cultivar or germplasm.Molecular characterization is needed to confirm or refute this hypothesis.Besides,when compared with sesame grown throughout the world,Moroccan sesame was found to be very promising,which open up the possibility to develop this crop in this country.

芝麻（Sesamum indicum L．）根系的解剖结构与耐涝强度的相关性研究

本文用常规石蜡切片法观察了耐涝芝麻品种根系与怕涝芝麻品种根系解剖结构的区别。用改良的丹尼管法测量了芝麻茎叶部分向根系输送氧气的数量，探讨了芝麻的抗涝机理。研究结果证明：耐涝芝麻品种根系具有皮层厚。皮层细胞呈柱状排列，皮层细胞间隙大等结构特征。当根系渍水时，耐涝芝麻品种的茎叶能向根系输送较多氧气，在一定程度上缓解了根系缺氧的状况。

Response of Hypercholesterolemic Rats to Sesamum indicum Linn Seed Oil Supplemented Diet

Fatty acid composition of Sesamum indicum oil was determined by gas chromatography and the response of hypercholesterolemic rats to diet supplemented with Sesamum indicum seed oil was investigated. Twenty four rats weighing between 120-130 g were randomly assigned into four groups. Group A was fed normal diet, Group B, C and D were fed hypercholesterolemic diet （i.e. 20% fat ＋ 1% cholesterol） for two weeks to establish hypercholesterolemia. Group B were maintained on hyper diet while C and D were fed 5% and 10% benniseed oil supplemented diet for four weeks. Plasma was collected and analyzed for TC （total cholesterol）, HDL-C （high density lipoprotein）, LDL-C （low density lipoprotein） and TG （triglycerides） levels. Linoleic acid （42.44%） and oleic acid （40.60%） were the major unsaturated fatty acid in the oil. Significant increase （P 〈 0.05） was observed in the TC, TG, LDL and LDL/HDL ratio of the hypercholesterolemic rats compared to the normal control. Supplementation with Sesamum indicum seed oil at 5% and 10% levels resulted in significant decrease （P 〈 0.05） in TC, TG, LDL and LDL/HDL ratio, and significant increase in the HDL-C. The high level of unsaturated fatty acid in the oil may in part be responsible for the hypocholesterolemic effect of the oil.

芝麻栽培种与野生种(Sesamum schinzianum Asch、Sesamum radiatum Schum & Thonn)种间杂交后代的生物学特性

【目的】探明芝麻栽培种与野生种种间杂交的亲和性,分析杂交后代遗传特征。【方法】以26个基因型(Sesamum indicum L.)与刚果野芝麻(Sesamum schinzianum Asch)和野芝1号(Sesamum radiatum Schum&Thonn)野生种为杂交亲本,借助胚培养技术获得种间杂交后代。采用SSR标记和生物学方法鉴定并分析杂交种F1的遗传特性。【结果】通过胚培养技术获得2 430个种间杂交F1株系,对部分材料的检测表明杂种阳性率为95.83%。刚果野芝麻×栽培种的正反交杂交率分别为34.62%(A)和11.54%(C),野芝1号×栽培种的正反交杂交率分别为100%(B)和19.23%(D)。F1花粉粒存在部分不育和高度不育两种类型,F1自交结实率分别为2.32—2.57粒/蒴果(S.schinzianum×S.indicum)和0.30—2.45粒/蒴果(S.radiatum×S.indicum)。【结论】S.radiatum与栽培种的杂交亲和率高于S.schinzianum。以野生种为母本与栽培种杂交,杂交种F1在株高、根系结构等性状方面超亲表现明显;株系高抗枯萎病;部分F1株系有低自交结实性。

Analysis on Genetic Diversity and Genetic Basis of the Main Sesame Cultivars Released in China

SRAP （sequence-related amplified polymorphism） was used for the analysis of 67 sesame （Sesamum indicum L.） cultivars widely used in Chinese sesame major production areas from 1950 to 2007. A total of 561 bands were amplified using 21 SRAP random primer pairs, with 265 of them were polymorphic, resulting in a polymorphism ratio of 47.2%. The total bands and polymorphism amplified by each primer pair averaged 26.7 and 12.6, respectively. The average genetic similar coefficient and genetic distance of the 67 cultivars were 0.9104 and 0.0706, respectively, indicating limited genetic diversity and narrow genetic basis. Comparative analysis on genetic similarity and genetic distance of different classified cultivars showed that the difference of average genetic similarity coefficient and genetic distance between the landraces and cultivars bred through crosses reached significant levels （P=0.01）, with the genetic basis of landraces wider than that bred cultivars. The genetic basis of cultivars used in 1990-2007 was more narrow than that of cultivars from 1950 to 1969 and from 1970 to 1989, with the differences of average genetic similarity coefficient and genetic distance reached 0.01 significant level. The genetic basis of Chinese sesame main cultivars is relatively narrow, and the genetic basis of cultivars developed through crosses in recent years is narrower than history cultivars.

Near-infrared reflectance spectroscopy reveals wide variation in major components of sesame seeds from Africa and Asia

Sesame is an important oilseed crop in Africa and Asia, owing to its high nutritional quality seed and market value. Variation in sesame seed components including oil, oleic acid,linoleic acid, and protein was investigated by near-infrared reflectance spectrometry in 139 samples collected from different countries. Oil and protein contents were between 40.8%and 60.3%(mean 53.0%) and 15.5% to 25.5%(mean 20.4%), respectively. Linoleic acid,ranging from 31.8% to 52.4%(mean 46%) was more abundant than oleic acid(31.8%–50.6%,mean 38.1%). Light-seeded samples displayed higher nutritional quality, as they were richer in oil, protein, and linoleic acid than dark seeds. Samples from Africa had higher oil and linoleic acid contents, while Asian samples had higher oleic content. The analysis revealed West African sesame cultivars containing especially high levels of seed components, which may command high market values. Two clusters of sesame samples grouped by seed composition were obtained, including one cluster with high oil and oleic acid content and the other with high protein and linoleic acid content. This study revealed that sesame samples from Africa and Asia harbor high variation for major seed components and also provided background information for breeding high-nutrition varieties according to the demands of sesame seed markets.

Influence of Acacia senegal agroforestry system on growth and yield of sorghum, sesame, roselle and gum in north Kordofan State, Sudan

We examined the effects of intercropping with Acacia senegal （L.） Willd on growth and yield of sorghum （Sorghum bicolor L.）, sesame （Sesamum indicum L.） and roselle （Hibiscus sabdariffa）. Field experiments were conducted in El-Obeid Research farm （13°10′ N; 30°12′ E）, North Kordofan State, Sudan, during 2002–2003 in an 11-year-old A. senegal plantation. The experimental design was randomized complete block design （RCBD） with four replications. Data were recorded for plant height （cm）, fresh weight （kg·ha-1）, dry weight （kg·ha-1）, crop yield （kg·ha-1）, and gum yield （kg·ha-1）. We used Land Equivalent Ratios （LER） and simple financial analyses of gross surpluses to evaluate the productivity and profitability of the different treatments. The results indicated that A. senegal trees had a beneficial effect on crop performance and yield as well as gum yield. Significant differences （p 〈 0.05） were obtained for plant height, fresh weight, dry weight and crop yield. Therefore, yield of sorghum, sesame and roselle under intercropping system were 13.7%, 23.8% and 20.9% higher than that obtained in the sole cropping system respectively. The highest yield increase was observed with sesame （23.8%）. Gum yield （g/tree/picking） was significantly （p 〈 0.05） increased for sorghum, sesame and roslle under intercropping system. The highest yield of （298 g/tree/picking） was obtained when roselle was intercropped with A. senegal, while the least gum yield of （239 gδtree-1） was recorded in pure A. senegal plot. All the treatments gave land equivalent ratio （LER） of more than one-indicating the superiority of growing the field crops in intercropping over the sole cropping systems. The highest LER of 3.8 was obtained for sesame intercropped with A. senegal （Hashab）, followed by 3.7, when sorghum was intercropped with A. senegal and 3.3 when roselle intercropped with A. senegal. All the treatments gave positive net revenues, the highest being for intercropped sorghum （558 SDG·ha-1） （SDG=Sudanese gienh）. The intercropping of roselle gave the second net revenue （518 SDG·ha-1）, while the sole sorghum gave the lowest net revenue （501 SDG·ha-1）.

Tolerance to Salinity of Sesame Genotypes in Different Phenological Stages

The sesame crop is usually avoided in salt-affected areas because of the various effects of saline stress on plants. Besides varying between species, salinity effects are known to vary for genotypes of the same species as well as plant development stages. Thus, through the irrigation of plants with saline water, this study evaluates tolerance to saline stress of new sesame genotypes in different phenological stages. Three experiments were carried out under greenhouse conditions, using the sesame genotypes BRS Seda, LAG-927561 and LAG-26514. Water with different levels of electrical conductivity (ECw = 0.6, 1.6, 2.6, 3.6 and 4.6 dS m-1) was used to irrigate plants during germination and initial growth stages, as well as the entire crop cycle. Tolerance to saline stress (3.6 dS m-1) during growth and production stages was also studied. Salinity did not affect sesame germination, but seedling growth was hindered from the ECw of 1.6 dS m-1 onwards, and plant height was the most affected growth variable. Seed production is affected by salinity, regardless of the phenological stage in which plants are exposed to salinity. The strains LAG-927561 and LAG-26514 show promising signs in studies on adaptation to saline stress.

Triple test cross analysis for seed yield and its components in sesame under water stress conditions

Water deficit is a limiting factor in sesame cultivars yield,thus identification of genetic mechanisms of sesame traits under water stress conditions is essential to development of water stress tolerant genotypes.Hence,the triple test cross(TTC)analysis in F_(2) population of the sesame cross(NA_(76)NA_(54))was used.Since,30 TTC families with their 13 respective parents were evaluated during the summer season 2020 under two irrigation treatments.i.e.,normal irrigation with 5952.38 m^(3) hm^(-2) of applied water,and water stress with 2976.19 m^(3) hm^(-2) of applied water.This was implemented at the experimental field of Kafr El Hamam/Sharkia,Agricultural Research Station,Agricultural Research Center(ARC),Egypt.Additive(D)and dominance(H)gene actions as well as epistatic and its two components of additiveadditive,additivedominance plus dominancedominance were involved in the inheritance of all studied traits under both irrigation treatments and their combined analysis.The degree of dominance(H/D)^(0.5) verified the presence of partial dominance in most cases.The correlation coefficient between sums(additive)and differences(dominance)was non-significant,showing that dominant genes between lines were ambidirectional.The moderately water stress tolerant TTC families as the best selected families were found in families 22,25,10,12,and 15.Therefore,postponing selection in these selected families to later segregating generations for all studied traits would be effective to exploit the positive effects of additiveadditive epistasis.

烟盲蝽用芝麻饲养的效果及捕食能力评估

烟盲蝽Nesidiocoris tenuis是一种杂食性天敌昆虫。本研究通过比较芝麻饲养和补充烟粉虱Bemisia tabaci猎物饲养烟盲蝽的生物学特征,评估了用芝麻人工饲养烟盲蝽的饲养效果和该种群对自然猎物的捕食能力。结果显示,用芝麻饲养的烟盲蝽若虫发育历期较长,成虫后足胫节长度较小。然而,烟盲蝽的雌性比例、存活率、成虫生殖力以及对烟粉虱和烟蚜的捕食量没有显著差异。两个种群连续繁殖10代时,芝麻饲养的烟盲蝽种群的内禀增长率为0.2152,与补充猎物饲养的烟盲蝽种群的内禀增长率0.2398相近。以上结果表明,仅用芝麻提供营养可以进行烟盲蝽的人工饲养,并且这种方法为烟盲蝽的规模化饲养和基于芝麻种植的田间饲养模式的建立提供了参考依据。

芝麻苗期干旱生理生化指标响应特征及其基因表达分析

为建立芝麻抗旱性快速鉴定体系及筛选芝麻抗旱品种,采用盆栽反复干旱法,设置正常水分(CK)和干旱胁迫(DS)两种处理,对31份芝麻材料进行生理生化指标测定和综合评价,同时利用qRT-PCR检测SOD合成相关基因的表达量。结果表明:芝麻苗期■、可溶性糖(SS)、脯氨酸(Pro)含量和超氧化物歧化酶(SOD)、过氧化物酶(POD)活性与CK相比均显著上升,各指标综合抗旱系数和抗旱指数的变异系数最高的分别是SOD(98.64%)和■(154.01%);抗旱指数与■含量、SOD活性呈极显著正相关关系,这两个指标可作为芝麻苗期抗旱性鉴定的重要指标。聚类分析将31份芝麻材料划分为5类抗旱类型,分别为高抗型、中抗型、低抗型、低感型和高感型。利用综合评价方法,筛选出高抗材料2份(‘汾芝10号’和‘豫-11-1’),中抗旱材料4份,低抗旱材料9份,敏感材料10份,高感材料5份;筛选出■含量和SOD活性可作为芝麻种质资源苗期抗旱特性快速鉴定的指标。

钾营养对花期干旱胁迫芝麻生长及叶片氮代谢的影响

为探究花期干旱胁迫下不同钾肥水平对芝麻(Sesamum indicum L.)生长和叶片氮代谢的影响,以及芝麻响应干旱胁迫的生理机制,以赣芝7号为试验材料,采用盆栽控水试验方法,设置3个钾肥水平(0、60、120 kg·hm^(-2);K_(2)O)和2个土壤水分处理(75%±5%和45%±5%田间持水量),对比不同钾肥水平下芝麻生长、氨基酸、可溶性蛋白含量、氮代谢酶活性等指标的差异。结果表明,干旱胁迫严重抑制芝麻生长,与正常灌水相比,干旱处理芝麻叶片相对含水量、株高、比叶重和叶绿素值分别平均下降8.2个百分点、23.5%、8.1%和6.6%。干旱导致芝麻叶片的氮代谢能力减弱,与正常灌水相比,干旱处理芝麻叶片的氮、钾、可溶性蛋白(SP)和氨基酸(AA)含量分别平均提高5.4%、10.6%、21.1%和52.7%,硝酸还原酶(NR)和谷氨酸合成酶(GOGAT)活性分别平均下降11.3%和16.6%。干旱胁迫下,与不施钾相比,施钾使芝麻叶片相对含水量、株高、比叶重、叶绿素值、钾、氮含量分别提高3.3~7.2个百分点、20.9%~39.0%、3.2%~5.5%、1.0%~4.5%、14.8%~19.6%、2.0%~5.4%;硝酸还原酶和谷氨酸合成酶活性分别提高8.7%~9.5%和15.1%~20.0%。相关性分析表明,干旱胁迫下,叶片钾含量与氮、SP、FAA含量及NR、GOGAT活性呈显著或极显著正相关(R^(2)=0.69~0.95)。综上所述,施钾可缓解干旱胁迫对芝麻造成的不利影响,提高叶片钾、氮含量及硝酸还原酶和谷氨酸合成酶活性;施钾主要通过调控渗透调节、蛋白质合成及氮代谢等途径来提高芝麻的耐旱性。本研究结果为芝麻抗旱栽培提供了科学依据。