Construction of SNP genetic maps based on targeted next-generation sequencing and QTL mapping of vital agronomic traits in faba bean(Vicia faba L.)

Owing to the limitation of a large genome size(~13 Gb),the genetic and gene mapping studies on faba bean(Vicia faba L.)are lagging far behind those for other legumes.In this study,we selected three purified faba bean lines(Yundou 8137,H0003712,and H000572)as parents and constructed two F2 populations.These two F2 populations,namely 167 F2 plants in Pop1(Yundou 8137×H0003712)and 204 F2 plants in Pop2(H000572×Yundou 8137),were genotyped using a targeted next-generation sequencing(TNGS)genotyping platform,and two high-density single nucleotide polymorphisms(SNP)genetic linkage maps of faba bean were constructed.The map constructed from Pop1 contained 5103 SNPs with a length of 1333.31 cM and an average marker density of 0.26 cM.The map constructed from Pop2 contained 1904 SNPs with a greater length of 1610.61 cM.In these two F2 populations,QTL mapping identified 98 QTLs for 14 agronomic traits related to the flowers,pods,plant types and grains.The two maps were then merged into an integrated genetic linkage map containing 6895 SNPs,with a length of 3324.48 cM.These results not only lay the foundation for fine mapping and map-based cloning of related genes,but can also accelerate the molecular marker-assisted breeding of faba bean.

Identification of Faba Bean(Vicia faba L.)Germplasm Resources in Hubei Province and Evaluation on Their Main Agronomic Traits

Through field observation and lab analysis, 13 agronomic traits, including plant height and effective branching number per plant, etc., of 207 faba bean （Vicia faba L.） germplasms saved in Crop Middle-term Genebank of Hubei Province were evaluated, moreover, the identification on the disease resistance and the quality was carried out on parts of germplasm resources. The results showed that the faba beangermplasm resources in Hubei Province were abundant, the variation range of agronomic traits like the growth period, plant height and 100-bean weight, etc., was great, and the range of choice was wide. In the aspect of quality, there were 9 germplasms withthe content of crude protein higher than 30%, and the variation range of amylose content in total starch was large, which provided excellent sources of parents for breedinq hi.qh-quality faba bean varieties in Hubei Province.

Yield stability and relationships among stability parameters in faba bean(Vicia faba L.) genotypes

Sixteen faba bean genotypes were evaluated in 13 environments in Ethiopia during the main cropping season for three years(2009–2011). The objectives of the study were to evaluate the yield stability of the genotypes and the relative importance of different stability parameters for improving selection in faba bean. The study was conducted using a randomized complete block design with four replications. G × E interaction and yield stability were estimated using 17 different stability parameters. Pooled analysis of variance for grain yield showed that the main effects of both genotypes and environments, and the interaction effect, were highly significant(P ≤ 0.001) and(P ≤ 0.01), respectively. The environment main effect accounted for 89.27% of the total yield variation, whereas genotype and G × E interaction effects accounted for 2.12% and 3.31%, respectively.Genotypic superiority index(Pi) and FT3 were found to be very informative for selecting both high-yielding and stable faba bean genotypes. Twelve of the 17 stability parameters,including CVi, RS, α, λ, S2 di, bi, S(2)i, Wi, σ2i, EV, P59, and ASV, were influenced simultaneously by both yield and stability. They should accordingly be used as complementary criteria to select genotypes with high yield and stability. Although none of the varieties showed consistently superior performance across all environments, the genotype EK 01024-1-2ranked in the top third of the test entries in 61.5% of the test environments and was identified as the most stable genotype, with type I stability. EK 01024-1-2 also showed a17.0% seed size advantage over the standard varieties and was released as a new variety in2013 for wide production and named "Gora". Different stability parameters explained genotypic performance differently, irrespective of yield performance. It was accordingly concluded that assessment of G × E interaction and yield stability should not be based on a single or a few stability parameters but rather on a combination of stability parameters.

Genetic Diversity Analysis of Faba Bean (Vicia faba L.) Based on EST-SSR Markers

Faba bean （Vicia faba L.）, one of the most important legumes in the world, evolved different types of cultivars due to its partial cross-pollination. The development of simple sequence repeat （SSR） markers from expressed sequence tags （EST） provided a useful tool for investigation of its genetic diversity. The purpose of the present study was to investigate the genetic diversity of faba bean from China and Europe using EST-SSR markers. 5 031 faba bean ESTs from the NCBI database were downloaded and assembled into 1 148 unigenes. A total of 107 microsatellites in 96 unigenes were identified, indicating that merely 8.36% of sequences contained SSRs. The most abundant SSR within faba bean was tri-nucleotide repeat motif, and among all the tri-nucleotide repeats, the motif AAG/CTT was the most abundant type. Based on these results, 11 EST-SSR markers were used to assess the genetic diversity of 29 faba bean cultivars from China and Europe with two to three alleles per locus. The polymorphism information content value ranged from 0.0644 to 0.4278 with an average of 0.2919. Principal coordinate analysis （PCA） and phylogenetic clustering based on these 11 EST-SSR markers distinguished these cultivars into different groups. The results indicated that faba bean in China had a narrow genetic basis, and the additional sources of genetic cultivars/accessions should be introduced to enhance the genetic variability. The results of this study proved that the EST-SSR marker is very effective in evaluation of faba bean germplasm.

Near-infrared spectroscopy(NIRS) evaluation and regional analysis of Chinese faba bean(Vicia faba L.)

To analyze the nutritional composition of faba bean(Vicia faba L.) seed, estimation models were developed for protein, starch, oil, and total polyphenol using near infrared spectroscopy(NIRS). Two hundred and forty-four samples from twelve producing regions were measured in both milled powder and intact seed forms. Partial least squares(PLS) regression was applied for model development. The model based on ground seed powder was generally superior to that based on the intact seed. The optimal seed powder-based models for protein, starch, and total polyphenol had coefficients of correlation(r2) of 0.97, 0.93 and 0.89, respectively. The relationship between nutrient contents and twelve producing areas was determined by two-step cluster analysis. Three distinct groupings were obtained with region-constituent features, i.e., Group 1 of high oil, Group 2 of high protein, and Group 3 of high starch as well as total polyphenol. The clustering accuracy was 79.5%. Moreover, the nutrition contents were affected by seeding date, longitude, latitude, and altitude of plant location. Cluster analysis revealed that the differences in the seed were strongly influenced by geographical factors.

Adaptation of faba bean varieties for yield, for yield components and against faba bean gall (Olpidium viciae Kusano) disease in South Gondar, Ethiopia

Faba bean(Vicia faba L.) has an important place in the Ethiopian national diet. It is consumed in various forms and contributes to the improvement of soil fertility. However,its production and productivity are affected by biotic and abiotic constraints. Among the biotic constraints, the emerging faba bean gall disease, caused by Olpidium uiciae, is the major and most destructive disease wherever faba bean is grown. Field experiments were conducted at two locations(Farta and Tach Gayint districts) to evaluate the reaction of faba bean varieties to faba bean gall disease and to assess them for yield and yield components during the 2014 and 2015 main cropping seasons. Thirteen faba bean varieties and one local check were plantecd in three replications Lusing a randomized complete block design. The disease incidence and severity of faba bean gall were recorded(on a 1-9 scale) five tinmes at10-day intervals. A combined analysis of variance showed za significant difference(P < 0.05)among faba bean varieties with respect to the incidence and severity of gall disease at both locations. Disease incidence, severity, and AUDPC were lowest for variety Turmsa at both locatiOons, but this variety showed lhigh yield only at tlhe Farta location. 'The lhighest yields were obtained from varieties Degaga(1157.74 kg ha ') and Nc58(828.97 kg ha ') at Farta and Tach Gayint, respectively and these varieties slhowed low faba bean gall severity and AUDPC. Thus, higher-yielding faba bean varieties such as Degaga and Nc58 are recommended for faba bean production areas in northwestern Ethiopia.

Effect of Varieties and Fungicide Rate on Chocolate Spot (Botrytis fabae) Disease of Faba Bean (Vicia faba L.) at Tach Gayint District in South Gondar Zone, Amhara Region, Ethiopia

Faba bean is suffered with many biotic and abiotic factors. Chocolate spot disease, caused by Botrytis fabae is one of the biotic factors limiting yields of this crop resulting in yield losses up to 68% in Ethiopia. The experiment was conducted during 2020/2021 cropping season at Tach Gayint district, Ethiopia to determine the integration of faba bean varieties and fungicide rates on reducing chocolate spot disease. The experiment consisted of 12 treatments, viz. three faba bean varieties and four rate of Mancozeb fungicide in factorial arrangement. The experiment was laid out as randomized complete block design (RCBD) with three replications. Data was collected and analyzed. Results indicated that, disease incidence was reached at maximum percentage in all treatments on the last dates of assessment. But treatments were significantly difference in severity level. The least disease severity was recorded from varieties treated by 3.5 kg/ha of Mancozeb 80% WP with mean values Walki (12.7%), and (18.1% and 20.8%) on Gora and local variety respectively at the final dates of disease assessment. Similarly, the reduced AUDPC was also recorded from varieties treated by 3.5 kg/ha of Mancozeb 80% WP with mean values Walki (371.8% unit/day) and (539% and 686.4% days) on varieties Gora, and Local respectively. Whereas the maximum disease severity and AUDPC were obtained from unsprayed plots. Based on the results obtained, variety Walki treated with Mancozeb 80% WP at rate of 2.5 kg/ha and 3.5 kg/ha were effective to reduce the effect of chocolate spot disease for the study area.

Quantitative Analysis of Pathway Enrichment within Faba Bean Seeds RNA-Seq (<i>Vicia faba</i>L)

Faba bean (Vicia faba L) seeds are an important source of plant protein for humans and animals. A total of 15,697 Differentially Expressed Genes (DEGs) with pathway annotation were discovered in RNA-Seq of the faba bean seeds. A total of 75 significant KEGG pathways abundance were discovered and 9 pathways were conserved within all genotypes. 41 significant pathways were found to be partially conserved within comparisons of 2 to 6 pairs of genotypes and 25 significant pathways were unique to single pairs of genotypes. There were 8 specific significant pathways discovered related to the faba bean seed Hydration Capacity trait and 9 specific significant pathways discovered related to the PSbMV seeds staining trait. The DEGs demonstrated the genetic distance between these varieties was confirmed by the breeding pedigree selection information and a PCA graph clearly illustrated the genetic distance within these genotypes.

Heterotic Effect, Combining Ability and Significance of Synthetics over Line Cultivars in Faba Bean (<i>Vicia faba</i>L.) Grown under Semi-Arid Zones

The aim of this study was to investigate the amount of heterosis and performance of faba bean synthetic cultivars compared to line cultivars under semi-arid conditions. Five inbred lines in at least S6 generation were developed and used to develop F1s hybrid (in all possible combination excluding reciprocal), lines mixtures (Syn-0) and synthetic generations of Syn-1. Evaluation of the entries showed the lines to have high general and specific combining ability, high yield and high average degree of cross-fertilization (0.36);hetrosis relative to mid-parent for yield was 67%. Lines mixture from four inbred lines (Hudeiba/93, Bassabier, Ed-Damar and Shabah) gave the highest yield of 3.40 t/ha for Syn-0 and 3.96 t/ha for Syn-1. Compared to the average yield t/ha of the pure stand of the four lines (3.11 t/ha), the increase in yield of was 9% in sy-0 and 27% in Syn-1. Compared to the individual yield t/ha of the pure stand of the lines, the performance of Syn-0 surpassed that of the individual pure stands of the linesby 14% for Hudiaba/93 and Bassabier and 4% for Ed-Damar and 7% for Shabah, whereas the increase in performance of Syn-1 compared to pure stand of the lines was 32%, 25% and 21%, respectively. The results confirm the previous knowledge on yield increase with successive syn-generations in faba bean due to the effects of heterogeneity and heterozygosity. Such results could be used as a base for an effective breeding program for improvement of yield of faba bean grown under the semi-arid zones.

A Comparison Study of Phenolic Contents and <i>in Vitro</i>Antioxidant Activities of Australian Grown Faba Beans (<i>Vicia faba</i>L.) Varying in Seed Coat Colours as Affected by Extraction Solvents

Twelve Australian grown faba bean genotypes with seed colour ranging from white, different shades of buff/beige, green, red and purple, were extracted using 80% methanol (v/v) or 70% acetone (v/v). The findings showed that commonly consumed buff-coloured genotypes have comparable phenolic contents and antioxidant activities to those with exotic seed coat colour (red, green and purple). In general, the extraction yield for methanol and acetone extracts of faba bean genotypes were similar. However, the acetone extracts of faba bean varieties with coloured seed coats exhibited higher antioxidant activities than their methanol extracts counterparts. Phenolic compounds and antioxidant activities of the genotypes were compared in an array of chemical-based assays and profiled using an on-line high-performance liquid chromatography-post column derivatization (HPLC-PCD) system. The total phenolic content (TPC) and total flavonoid content (TFC) of acetone extracts were approximately twice those of methanol extracts. The acetone extracts contained six times higher levels of di(phenyl)-(2,4,6-trinitrophenyl) imi- noazanium radical scavenging activity (DPPH), six times higher Total Equivalent Antioxidant Capacity (TEAC) and two times higher Ferric Reducing Antioxidant Power (FRAP) than those of methanol extracts. In general, the methanol extracts of white-coloured faba bean genotype exhibited comparable phenolic contents and antioxidant activities to varieties with coloured seed coats. However, the TPC, TFC, DPPH, TEAC and FRAP of acetone extracts from white-coloured genotype were 2 - 4, 1 - 2, 5 - 9, 2 - 3 and 1 - 2 times lower than those of faba bean varieties with coloured seed coats. HPLC-PCD analyses showed substantial antioxidant responses, represented as a dense “hump” of peaks in the HPLC chromatograms of acetone extracts from coloured-genotypes. This “hump” was not detected in the chromatograms of white-genotype acetone extracts, or in chromatograms of methanol extracts regardless of genotype or seed coat colour. All coloured-beans had higher phenolic contents and antioxidant activities than the white-genotype. Hydroxybenzoic acids/flavanols, hydroxycinnamic acids and flavonols were dominant in coloured beans. The findings suggest potentials in selecting commonly consumed buff-coloured faba bean genotypes within the breeding programs for enhanced levels of phenolic compounds and antioxidant activities, potentially increasing their health-promoting properties. And, there might also be potentials in developing faba bean extracts for pharmaceutical or natural medicines.

Impact of Bee Pollination on Yield of Faba Bean (<i>Vicia faba</i>L.) Grown under Semi-Arid Conditions

The effect of honeybee (Apis mellifera carnica) on yield was investigated in open-pollinated faba bean cultivars and three inbred generations produced from them (once-selfed, twice-selfed, and thrice-selfed). All entries were grown in cages under two pollination conditions: presence of bees (cross-pollination) or absence of bees (self-pollination). The open-pollinated generations gave the highest performance in the presence and absence of bees. In the presence of bees, the open-pollinated and their inbred entries gave higher performance in all of the studied traits than in the absence of bees;the average improvement in yield and its components was 22%. The highest improvement percentage in yield performance was shown by more inbred entries (thrice-selfed > once-selfed), indicating that in faba bean populations, the performance of inbred generations was chiefly associated with the tripping of flowers, which is usually governed by successfully fertilized flowers, i.e., plants result from selfing in faba bean population needs to be visited by pollinating insects (bees) to set more seeds. It concluded that honeybee has an important role in increasing faba bean yield in semi-arid conditions;hence, it is important to provide a pollinator friendly environment for their foraging places and nesting sites to secure food supply.

Correlation Analysis and Principal Component Analysis of Eight Agronomic Traits of Autumn Broad Beans (Vicia faba L.)

[Objectives] This study was conducted to give play to the yield-increasing potential of new broad bean varieties. [Methods] The correlation analysis and principal component analysis of eight main agronomic traits of 15 autumn-sown broad bean varieties in 2017-2018 were carried out. [Results] There were extremely complicated correlations between the agronomic traits. Among the various agronomic traits, the number of pods per plant showed a significant negative correlation from the number of seeds per pod(P<0.05), and significant negative correlations with pod length and 100-grain weight(P<0.01). The number of seeds per pod was significantly positively correlated with pod length(P<0.01). The 100-grain weight of broad beans was significantly positively correlated with the pod length(P<0.01), and was significantly negatively correlated with the number of pods per plant(P<0.01). Three principal components were established by principal component analysis, and the contribution rate of the first principal component was the highest, which was 40.18%. The contribution rates of the second principal component and the third principal component to the total variance were 24.08% and 13.55%, respectively. The score equations of the principal components were derived. [Conclusions] This study provides a theoretical reference for the application and promotion of new varieties of autumn broad beans.

Chitosan Seed Priming Improves the Yield and the Root System of Faba Bean(Vicia faba L.)Short Title:Chitosan Impact on Yield of Faba Bean

Faba bean is an important legume crop with food and feed applications.Since 2015,the culture of faba bean has decreased in France.Poor yield caused by climate change is proposed as one of the main reasons.Chitosan is a promising biopolymer with empirically proved impact on germination and disease tolerance of faba bean.However,the impact of chitosan seed priming on germination and yield of this plant is not experimentally studied.We followed chitosan primed faba bean seeds,from sowing until maturation,using germination,fruit and grain parameters.We observed that chitosan seed priming ameliorated several yield related traits.Germination rate,length of radicle and seedling,radicle dry matter,number of pods/plants,number of grains/pods were increased in chitosan primed faba beans.Total grain mass/plant increased up to 47%in treated plants.The probable underlying mechanisms,namely,root enhancement nitrogen metabolism,and elicitation of immune system are discussed.We conclude that,chitosan seed priming with compatible commercial preparations could be a potential solution to recompensate the loss of yield under variable climate conditions.

Relationship between Seed Yield and Yield Chracteristics in Faba Bean （Vicia faba L.） by GGE-Biplot Analysis

Viciafaba L. was domesticated around 8000 BC in the Near East; the crop spread to Central Europe and Russia through Anatolia, the Danube Valley and the Caucasus; to Eastern Mediterranean regions through the Mediterranean coast and the Isles; from Egypt and Arabian Coast （the Arabia Felix） to Abyssinia; through Mesopotamia to India and China probably during the first millennium AD （only land races of major type, the latest in being produced, were known in China until recently）. Faba bean （Vicia faba L.） is grown world-wide as a protein source for food and feed. The importance of nutzients （micro and macro） for human growth is universally recognized. An investigation was camed out to select the most successful faba bean genotypes to estimate for seed yield and some of agro-morphological traits. Effective interpretation of the dataon breeding programes is important at all stages of plant improvment. The GT （genotype by trait） was used for two-way faba bean genotypes with multiple traits. For this purpose, six faba bean genotypes with specific components were tested and the GT biplot for genotype data explained 83% of total variation of the standardized data. The polygon view of GT presented for five traits of faba bean genotypes showed three vertex genotypes as Goryaka, Karcacaoglan and Seher. Genotype G0ryaka had the highest values for most of the traits. It was demonstzaited that the selection of high seed yield will be via hundred seed weight and planth height. These traits should be considered meanwhile as effective selection criteria developing high yielding faba bean genotypes because of their large contibution to grain yield. The genotypes Goryaka and Karacaoglan could be well-considered for improving of desirable candidate in selection of improvement studies.

Nanoparticle Treatments Based on Zinc Oxide and Moringa oleifera Leaf Extracts Alleviate Salinity Stress in Faba Bean (Vicia faba L.)

Salinity stress limits crop growth and productivity, including legumes in various regions worldwide. The impact of foliar-applied zinc nanoparticles (ZnNPs) and combined zinc nano-loaded with moringa extracts (ZnONPs) on salt tolerance in faba beans (cultivar, Giza-716) grown under saline soil (50 and 100 mM NaCl) was investigated. Moringa oleifera extract has been used as a chelating agent to synthesize zinc oxide nanoparticles. The crystalline structure, morphology, and chemical composition of ZnO nanoparticles were studied using various characterization techniques, including UV-visible spectroscopy (UV), Fourier Transform Infrared Analysis (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Morphological, chemical, and biochemical parameters of plants at 60 and 90 days after sowing were assessed. Salinity stress caused a remarkable reduction in growth traits, photosynthetic pigments and proline levels of the faba bean. Foliar spray with ZnNPs and ZnONPs on faba bean grown under saline soils promoted plant growth parameters (i.e., shoot length, numbers of leaves, relative water content, shoot and roots fresh and dry weights), photosynthetic pigments (Chl a, b, total chlorophyll, and carotenoids), proline and mineral elements (Na+, K+, Ca2+, and Zn2+) compared to control. However, at 100 mM NaCl, there were no significant variations in the mentioned parameters. This study suggested that there is potential for foliar spraying with ZnNPs and ZnONPs in improving growth parameters, photosynthesis efficiency and biochemical aspects of faba bean plants under saline conditions.

Assessment of Factors Influencing Chocolate Spot (Botrytis fabae) Disease Epidemics of Faba Bean (Vicia faba L.) at Tach Gayint District in North Western Ethiopia

Faba bean (Vicia faba L.) is one of the oldest domesticated food legumes that have been cultivated for at least 5000 years. It is a multi-purpose crop that plays an important role in the socio-economic life of farming communities in Ethiopia. Chocolate spot disease, caused by Botrytis fabae is one of the yield limiting factors of this crop resulting in yield losses up to 68% in Ethiopia. A field survey was conducted in Tach Gayint district South Gondar Administrative Zone during the 2020/2021 main cropping season to assess the importance of the chocolate spot disease of faba bean. A total of 60 faba bean farmer fields were assessed in six (6) Kebele Administrations and most farmer fields were affected by chocolate spots. But the status of disease incidence and severity was varied. Significant differences among locations were observed due to altitude, soil type, planting density, date of planting, crop growth stages and farm history of the fields. Independent variables like Altitude, farm history, crop growth stage, date of planting and planting density were significantly associated with both disease incidence and severity when entered first and last into a model. The finding indicates that the lowest plant density and late planting of the crop reduce the incidence and severity of the disease.

Effect of Flower Removal on Senescence and Metabolism of Faba Bean(Vicia Faba L.)

In pot experiments at Xichang,China,during 1989～1994,visual senescencesymptoms and associated changes in constituent contents and activities of leaves of fababean(Vicia faba L.)were compared in respones to flower removal.The leaves from upper,middle and lower positions were sampled six times during reproductive developmentphase.At 70 DAP flower removal had caused 37%～189% and 82%～197% increase ofgreen leaf area and green leaf dry weight per plant respectively.Flower removal led to asignificant increase in the chlorophyll,soluble sugar and protein contents and the catalaseactivity.The leaf cell relative electroconductivity of those plants was maintained at a lowerlevel,relative to the control,during the late growing stage.These results certainly impliedthat the leaves of flower removal plants were still fully functional at a very late growingstage,consequently the plants increased many new branches per plant.

重金属对蚕豆(vicia faba)根尖的核酸含量及核酸酶活性影响的研究

Pb^(2+)、Cd^(2+)、Zn^(2+)在低浓度作用下,随处理浓度的升高,刺激蚕豆(Vicia faba)DNA含量(处理浓度分别低于10.0、0.50、50.0ppm)和RNA含量(处理浓度分别低于10.0、50.0、50.0ppm),DNase活性(处理浓度均低于10.0ppm)和RNase活性(处理浓度分别低于20.0、10.0、50.0ppm)相应地升高;当处理浓度超过相应浓度时,DNA和RNA含量以及DNase与RNase活性随浓度升高而降低。Hg^(2+)在小于0.05ppm时使RNase活性升高,高于该浓度使其降低,其它各指标无上述规律性变化。重金属对核酸代谢的影响结果取决于植物组织的适应性反应与金属离子的毒性反应的强度。文章还讨论了金属离子特征和可能存在的不同代谢活动的抗性诱导体系对植物毒性的影响,以及蛋白质的代谢活动对植物适应性水平的影响。

Effect of Localized Scorch on the Transport and Distribution of Exogenous Jasmonic Acid in Vicia faba

Exogenous jasmonic acid (JA) has been showed to be able to induce stomatal closure in Vicia faba L. in previous investigations. The transport and distribution of 3H-JA affected by localized scorch on V. faba seedling were studied with radioisotope technique. The results showed that 3H-JA could be transported up or down at the rate of 4-5 cm·min -1 following feeding into root or shoot tip. The transport of 3H-JA in shoot reached a relative stable rate at 30 min after being fed through root. Wounding by scorch in the youngest leaf caused an increase in the transport of 3H-JA from root to shoot and enhanced the distribution of 3H-JA in the wounded leaf. However, distribution of 3H-JA in unwounded leaves increased after 5 h being fed through the youngest leaf. It was noticed that wounding improved accumulation of 3H-JA in abaxial epidermis. Consistent results were obtained: wounding prevented transport of 3H-JA out from the youngest leaf to root; These observations suggest that JA plays an important role as a defense signal and might be involved in the regulation of the stomatal movement in response to wounding stress.

Cd^(2+)、Al^(3+)对蚕豆(Vicia faba)DNA合成及修复的影响

利用３Ｈ－ＴｄＲ 掺入方法，研究了不同浓度单金属离子Ｃｄ２＋ 、Ａｌ３＋ 对蚕豆ＤＮＡ 合成、ＤＮＡ 修复（以ＵＤＳ为指标）的影响。结果表明：在低浓度Ｃｄ２＋ 、Ａｌ３＋ （Ｃｄ２＋ 浓度＜ ２０ｍ ｇ／ｌ，Ａｌ３＋ 浓度＜ １００ｍ ｇ／ｌ）处理后，蚕豆ＤＮＡ 合成加快，并且不同程度地诱导了ＵＤＳ的发生；但在高于此浓度的Ｃｄ２＋ 、Ａｌ３＋ 作用下，蚕豆ＤＮＡ合成受抑制，浓度越高，抑制作用越强；并且几乎不表现出ＵＤＳ效应。这一结果说明Ｃｄ２＋ 、Ａｌ３＋ 对蚕豆的遗传物质ＤＮＡ有损伤作用。在一定受损范围内，蚕豆自身有ＤＮＡ损伤修复能力，超过这个限度，ＤＮＡ损伤不能被修复。Ｃｄ２＋ 、Ａｌ３＋ 对ＤＮＡ 合成和修复的影响是高等植物金属中毒的机制之一。