Identification and Evaluation of Cold Tolerance in Bitter Gourd (Momordica charantia L.) at Bud and Seedling Stages under Different Temperature Conditions

[ Objectives] This study was conducted to screen the temperature index most suitable for identification of cold tolerance in bitter gourd （Momordica charantia L. ） at bud and seedling stages. [ Methods] With six different bitter gourd germplasms as experimental materials, the cold tolerance at bud and seedling stages were identified and evaluated. [ Results] At 18℃ , the largest change range of germination potential among different gernlplasms was 11.3% -96.0%, and the largest change range of germination rate was 13.3% - 100.0% ; and the six germplasms could be divided into three grades of cold tolerance. Therefore, 18 9C is an ideal temperature for the identification of cold tolerance in bitter gourd germplasms at bud stage. At 20℃, the cold tolerance in bitter gourd germplasms at bud stage could also be divided into three grades, and the change ranges of germination potential and germination rate were larger than 50.0%, so 20℃ could serve as the candidate temperature for the identification of cold tolerance in bitter gourd germplasms at bud stage. After 1 d of treatment at 6℃, the six bitter gourd germplasms could be divided into three grades, and the cold injury index had the largest range of 20.31 - 84.38 and could serve as the temperature index for the identification of cold tolerance in bitter gourd at seedling stage. [ Conclusions] This study will provide reference for the identification of cold tolerance in bitter gourd at bud stage and seedling stage.

Identification of Tip-burn of Six Chinese Cabbage Varieties at Seedling Stage

[ Objective] The paper was to discuss the incidence regularity of Chinese cabbage tip-burn. [ Method] With five Chinese cabbage varieties bred by Zhengzhou Vegetable Research Institute and Beijing Xinsanhao as materials, the incidence regularity of tip-burn was studied using Chinese cabbage tip-burn identification method at seedling stage. [ Result] The disease index of tip-burn generally increased with the prolongation of culture time, but all varieties successively reached high susceptibility state at 45 d of calcium deficiency culture, and the disease basically reached a stable state at 55 d. Zhengbai 65 showed the best resist- ance in calcium deficiency treatment, while Zhengbai 4 displayed the worst tolerance and was very sensitive to calcium deficiency, with poor buffering capacity. Zhengbai 80 performed good buffering capacity in the early stage of calcium deficiency, but with the prolongation of culture time, the incidence developed rapidly in late stage. Other varieties showed different resistance and sensitivity, but they reached the stable incidence period almost at the same time point. [ Conclusion] The results provided a reference for prevention and control of tip-burn.

Changes in DNA Methylation Pattern at Two Seedling Stages in Water Saving and Drought-Resistant Rice Variety after Drought Stress Domestication

Recent studies revealed that DNA methylation plays an important role in plant growth and development. In this study, a water-saving and drought-resistant rice variety Huhan 3 was subjected to drought stress from tillering to grain-filling stages in six successive growth cycles. The variations in DNA methylation pattern between the original generation （Go） and the sixth generation （G6） were analyzed by using methylation sensitive amplification polymorphism method. The results revealed that the methylated loci accounted for 34.3% to 34.8% of the total loci. Among these methylated loci, 83.1% to 84.8% were full- and hyper-methylated and 15.2% to 16.9% were hemi-methylated. The DNA methylation level decreased from the three-leaf to four-leaf stages in Huhan 3. Differentially methylated loci （DML） between generations or/and between different developmental stages accounted for 4.0% of the total loci, most of which were only related to plant development （57.9%）. Compared to Go, the DNA methylation pattern of G8 changed after drought domestication, at the three-leaf stage, de-methylation accounting for 59.1%, while at the four-leaf stage, re-methylation for 47.9%. Genome-wide alternations of DNA methylation were observed between the two seedling stages, and DML mainly occurred on the gene＇s promoter and exon region. The genes related to DML involved in a wide range of functional biology and participated in many important biological processes.

Identification of a Tobacco Disease on Flat Tray System

[ Objective] The pathogen of a new disease found in floating seedlings of tobacco was isolated and identified to provide the basis for the control of the disease. [ Method] The pathogenicity of the isolated strain was determined according to Koch＇s rules, and the pathogen was identified through Biolog system, 16S rDNA sequence analysis and physiological and biochemical methods. [ Result] Through Koch＇s test, the isolated 3 -3 strain was verified to be the pathogen causing floating seedling disease, which was consistent with the characteristics of Pectobacterium carotovo- rum subsp. Carotovorum through Biolog determination and the other physiological and biochemical methods. 16S rDNA sequence analysis showed that 3 -3 strain had the highest similarity with P. carotovorum subsp. Carotovorum strains Kun28213 （accession number GU936996）, reaching 99. 9%. [Conclusion] Base on the identification results of several methods, the pathogen causing floating seedling disease was P. carotovorum subsp. Carotovorum, and the disease was first reported in China. According to the English name of the disease, the disease was called as tobacco blackleg disease.

The Research on Identification of Resistance to Sorghum Aphid [Melanaphis Sacchari(Zehntner)] Employing Indoor Artificial Infestation Technique

[ Objective] The paper was to establish a quick and effective indoor identification method of sorghum resistance to aphid uninfluenced by seasons. [ Method] Based on the indoor reproduction technique of aphids, the sorghum varieties with different resistant performances against aphids in fields were conducted inoculation test in the laboratory according to different seedling culture media, different survey periods of aphid quantity, different leaf ages for inoculation, different inoculation quantity of aphids and different aphid sizes. Three hundred sorghum materials were identified in both laboratory and field. [ Result ] The number of aphids per seedling on the fifth day after inoculation gave the best score of plant resistance to sorghum aphid by using the loam as the seedling culture media, and inoculating three different sizes of aphids in seedlings at two-leaf stage. Thus, the indoor identification technique of resistance to sorghum aphids was as follows ： （ 1 ） sorghum seeds were sown in loam at room temperature of 22 - 26 ℃ and air humidity of 55% - 75% ; （2） three aphids with different sizes were inoculated in scedIings at two-leaf stage; （3） the number of aphids per seeding were surveyed on the fifth day after inoculation; （4） plant resistance to sorghum aphid was evalu- ated according to number of aphids per seedling on the fifth day after inoculation. The resistant grade of sorghum variety was evaluated according to distribution of aphid quantity per seedling in a 100-seedlings population. The resistance materials identified by indoor method at seedling stage had consistent performance with fidd identification. [ Conclusion] The method could be used for resistance identification of sorghum varieties and hybrids, and accurate identification and selectlon of individual resistance of hybrid offspring, which could improve selection efficiency of individual resistant plant against aphids in hybrid offspring and identification accuracy of individual resistant plant among molecular marker population.

Identification of seedling cabbages and weeds using hyperspectral imaging

Target detection is one of research focuses for precision chemical application.This study developed a method to identify seedling cabbages and weeds using hyperspectral imaging.In processing the image data with ENVI software,after dimension reduction,noise reduction,de-correlation for high-dimensional data,and selection of the region of interest,the SAM(Spectral Angle Mapping)model was built for automatic identification of cabbages and weeds.With the HSI(Hyper Spectral Imaging)Analyzer,the training pixels were used to calculate the average spectrum as the standard spectrum.The parameters of the SAM model,which had the best classification results with 3-point smoothing,zero-order derivative,and 6-degrees spectral angle,was determined to achieve the accurate identification of the background,weeds,and cabbages.In comparison,the SAM model can completely separate the plants from the soil background but not perfect for weeds to be separated from the cabbages.In conclusion,the SAM classification model with the HSI analyzer could completely distinguish weeds from background and cabbages.

棚栽与瓶栽金线莲的广靶代谢组学比较

[目的]基于广泛靶向代谢组学技术,探索瓶栽和棚栽金线莲主要代谢产物的差异,为鉴别不同栽培方式的金线莲产品提供依据。[方法]以金线莲主栽品种‘红霞’为研究对象,采用UPLC-MS/MS分析技术对比了组培瓶苗驯化6月龄(瓶栽)与大棚栽培6月龄(棚栽)的金线莲全草干品之间的差异代谢物,并进行了标识代谢物筛选和差异代谢物通路富集分析。[结果](1)棚栽和瓶栽金线莲平均株高分别为11.37、9.90 cm,叶片数分别为8.75、5.75片,单株干质量分别为0.43、0.23 g,棚栽均极显著高于瓶栽;瓶栽和棚栽金线莲苷含量分别为138.75、144.75 g·kg^(-1),蛋白质含量分别为129.75、133.13 g·kg^(-1),棚栽略高于瓶栽,但两者差异不显著。(2)在两种干品中共检测到880种代谢物,从中筛选到差异代谢物89种,其中棚栽有55种上调表达、34种下调表达。含量较高的标识代谢物中,棚栽金线莲有22种,主要为黄酮醇、酚酸类和核苷酸及其衍生物等化合物;瓶栽有10种,主要为酚酸类、生物碱和游离脂肪酸等化合物。(3)通路富集分析结果显示,89种显著差异代谢物分布在48条代谢通路中,显著富集的有硫胺代谢,VB_(6)代谢,丙氨酸、天冬氨酸和谷氨酸代谢,生物素代谢,泛醌和其他萜类醌生物合成,黄酮和黄酮醇生物合成,嘌呤代谢,氨酰基tRNA生物合成,氰基氨基酸代谢,醚脂代谢,叶酸生物合成等途径。[结论]仅检测金线莲苷和蛋白质含量,无法区分瓶栽和棚栽金线莲产品。在差异代谢谱中,二者各有上下调表达,差异代谢物数量和含量都以棚栽金线莲具有显著优势,可为两种栽培品的鉴别提供依据。此外,在标识性代谢物中,金线莲的有效成分黄酮类、酚酸类等,也以棚栽具有显著优势,可为金线莲高质量栽培提供参考。

217份一粒系小麦苗期抗条锈病鉴定及抗病基因检测

小麦条锈病是影响小麦生产的重要病害之一。发掘新的抗病基因,培育新的抗病品种是防治小麦条锈病最经济有效的措施。一粒系小麦作为普通小麦的二级基因源,蕴含了丰富的抗病资源。为了从一粒系小麦中发掘新抗病基因,促进其利用,本文对217份一粒系小麦材料进行了苗期抗条锈病鉴定和A基因组的部分抗条锈病基因检测。结果表明,共有55份材料在苗期对CYR32表现抗病,占25.35%;抗病基因分子标记检测显示,携带Yr1、Yr34/Yr48、Yr69、Yr76抗性基因的材料分别有26、22、16、34份。共有4份表现高抗或免疫的材料同时携带2个抗性基因:2份材料携带Yr69和Yr34,2份携带Yr1和Yr34。所有供试材料中均未检测到Yr17。此外,有23份抗病材料未检测到以上抗病基因,其中7份表现高抗及免疫,可能携带其他已知或新的抗条锈病基因。本研究为一粒系小麦的利用提供了参考信息。

棉花远缘杂交新种质耐盐性鉴定及生理特性分析

为探究盐胁迫对棉花生理机制的影响,以耐盐碱棉花中J0710为对照,对山西农业大学棉花育种课题组培育的2个棉花远缘杂交新种质HL2、A_(2)H幼苗进行为期15 d的盐溶液处理(浓度为200 mmol/L),分析参试材料的相对株高、相对根长及相对成活率,计算盐害指数;并结合不同处理时间(0,5,12,24,48 h)的幼苗原初光能转化效率(Fv/Fm)、抗氧化酶活性、脯氨酸含量、可溶性糖含量等生理指标的测定结果,对参试材料的耐盐性进行综合评价。结果表明,盐胁迫15 d后,对3个材料幼苗生长的伤害程度由弱到强依次为中J0710<HL2<A_(2)H,盐胁迫极显著抑制了A_(2)H的相对株高、相对根长及相对成活率,说明该盐浓度处理下,对HL2及中J0710的生长发育影响较小,而对A_(2)H的影响较大。在不同的处理时间下,盐胁迫对3个材料的最大光能转化效率均具有不同程度的影响,相较于胁迫前,抑制程度由弱到强依次为HL2<A_(2)H<中J0710。相较于未胁迫之前,盐胁迫提高了过氧化物酶(POD)活性;其中,整个胁迫过程中HL2的POD活性显著高于A_(2)H和耐盐对照中J0710,并且在胁迫12~48 h达到显著水平;超氧化物歧化酶(SOD)活性变化规律不明显,且在盐胁迫过程中发挥作用较低;HL2及耐盐对照中J0710的脯氨酸含量积累量均随着盐胁迫时间的延长而增多,种质HL2的可溶性糖及可溶性蛋白含量在整个盐胁迫期间均显著高于耐盐对照中J0710和A_(2)H。综上,在盐逆境中,耐盐材料具有较发达的根系;而较高的光能转化效率、细胞内较高的活性氧清除能力以及较高的渗透调节物质的积累是其耐盐性较强的生理基础。

稻种资源苗期田间抗旱性鉴定技术规程

作物田间抗旱性是一个复杂的数量性状,准确的表型鉴定是数量性状基因发掘和遗传基础研究的关键。而稻种资源田间抗旱性表型的准确鉴定一直是该领域的卡脖子难点,也是抗旱育种工作者所关注的核心技术步骤。本文在前期系统的抗旱性研究基础上,通过多年对田间抗旱性鉴定体系的探索优化,总结制定了包括一般要求、整地、备种、播种、施肥、水分管理、病虫草害防治、苗期群体抗旱性调查与评价等全过程的操作规范和基本要求,为作物种质资源苗期田间抗旱性鉴定提供技术参考。该技术规程适用于海南省三亚市每年冬季(11月中旬-次年4月上旬)的苗期田间抗旱性鉴定。

玉米苗期耐盐性鉴定技术研究及耐盐自交系筛选

土壤盐碱化使耕地利用率降低,作物生产受到限制。玉米耐盐种质的鉴定及筛选在盐碱地改良利用中具有重要意义和应用前景。本研究为筛选玉米苗期耐盐鉴定的最适NaCl浓度,选取16份代表性自交系进行0(对照)、100、150、200、250、300 mmol/L NaCl处理7 d,测定株高、根长、地上部鲜重、地下部鲜重、地上部干重和地下部干重6个指标,并记录苗情。结果表明,盐处理7 d后,与对照相比,150 mmol/L NaCl处理的各指标存在显著差异,并且比其他盐浓度处理的变异系数更大,由此确定150 mmol/L为玉米自交系苗期耐盐鉴定的最适浓度。据此本研究建立了玉米苗期150 mmol/L NaCl处理的多指标综合评价耐盐鉴定技术。利用该技术对76份玉米自交系进行分析,通过加权隶属函数法计算耐盐综合评价指数D并聚类分析,将76份玉米自交系划分为高耐盐、耐盐、盐敏感及盐高敏4个类群,其中明71、中106、四-287和8112苗期耐盐能力较强,可作为玉米耐盐育种的优异资源;地上部鲜重耐盐系数与D值相关性最高,可作为玉米自交系苗期耐盐性评价的主要指标。

大豆种质资源苗期耐盐鉴定及遗传多样性分析

盐碱地是边际土壤的主要类型之一,利用边际土地耕作是减缓耕地紧缺的有效途径。为筛选耐盐性较强的大豆种质资源,提高盐碱土地大豆产量,本研究对392份来自国内外不同地域的大豆种质资源,采用150 mmol/L NaCl进行苗期盐胁迫处理,采用单株分类记载法进行苗期耐盐性鉴定,并利用10个与耐盐基因连锁的SSR标记对高耐及耐盐等级大豆种质资源进行分子辅助鉴定及遗传多样性分析,应用相似性系数分析、聚类分析等方法对高耐及耐盐等级大豆种质资源进行综合评价。结果表明:筛选出58份高耐及耐盐大豆种质资源,包括赤豆1号、东农69等高耐大豆种质资源14份,黑农51、黑河35等耐盐大豆种质资源44份;58份耐盐大豆种质资源分子辅助鉴定表明,绥农1号、合丰50和东大2号携带耐盐等位变异最多,均为6个,标记平均鉴定效率为43.45%,平均准确率为68.46%,其中分子标记Satt201的鉴定效率和鉴定准确率最高,分别为60.34%和96.55%;聚类分析表明,58份大豆种质资源间的相似性系数在0.5385~0.9231之间,平均值为0.6974,相关系数为0.6240,说明58份大豆种质资源大部分遗传关系较近,遗传多样性较低,58份耐盐大豆种质资源并未按地域进行聚类,但一个类群或亚群中大部分种质资源来源地在地理位置上相同或较为接近,可从中筛选亲缘关系较远的大豆种质资源作为亲本,用于培育耐盐大豆新品种奠定遗传基础。

向日葵种质资源的耐盐性评价

为了解向日葵种质资源的耐盐性,鉴定发掘向日葵耐盐优异种质,对444份种质资源分别进行了芽期(250 mmol/L NaCl)、苗期(250 mmol/L NaCl)耐盐鉴定和盐碱地全生育期种植观察,通过测定芽期发芽率、苗期存活率、叶面积、株高、SPAD值等6个苗期指标和全生育期株高、葵盘直径、结实率、相关产量等7个指标的相对值(各指标与对照处理的相应比值)进行耐盐性分析评价。相关性分析结果表明苗期两两指标间均呈极显著正相关,相关系数在0.518-0.790之间;全生育期7个指标中多数指标间的相关性都达到了显著或极显著水平。基于指标相对值进行主成分分析、隶属函数值计算、耐盐性综合评价和聚类分析,筛选出芽期耐盐及以上种质132份、苗期耐盐及以上种质9份、全生育期耐盐及以上种质41份,其中6份种质(ZX0365、ZX0389、ZX1391、ZX1394、ZX3089、ZX3094)在3个时期均表现为耐盐及以上等级,综合耐盐性好,可作为耐盐基因挖掘和耐盐品种选育等后续利用的种质材料。对其中124份种质3个时期(芽期、苗期、全生育期)的耐盐等级进行相关性分析,结果表明各时期的耐盐性鉴定结果极显著相关,芽期和苗期的耐盐鉴定结果可为盐碱地种植向日葵选择耐盐材料提供有效参考。本研究为向日葵耐盐品种选育提供了方法和材料基础。

小麦芽期和苗期耐盐鉴定方法的适用性评价

耐盐鉴定是筛选种质和选育耐盐小麦品种的前提。小麦室内耐盐鉴定方法较多,涉及不同生育时期和组织器官。为了评估这些方法在生产上的适用性,本研究选用北方冬麦区5个耐盐品种和5个盐敏感品种为试验材料,对基于芽期和苗期的7种耐盐鉴定方法(涉及27个测试指标)进行实用性评价。结果显示,利用小麦种子的发芽相对盐害率不能区分参试耐盐品种和盐敏感品种,而小麦苗期的叶部盐害指数、根部Na^(+)和K^(+)流速以及根尖数、根径、叶片K^(+)含量的相对盐害率在耐盐和盐敏感品种之间差异显著。综合回归分析结果和可操作性,明确叶部盐害指数是北方冬麦区适用性较高的耐盐鉴定方法,可结合根尖数相对盐害率、叶片K^(+)含量相对盐害率或根部Na^(+)和K^(+)流速用于种质筛选或品种选育。本研究从适用程度方面解析和评价了耐盐鉴定方法,为小麦耐盐育种工作提供参考信息。

山西小麦苗期耐低磷特性及遗传分析

【目的】干旱与半干旱地区的水肥资源贫乏,而小麦不同基因型间的磷效率差异很大,因此,鉴选耐低磷种质、挖掘磷代谢遗传位点有助于小麦的遗传改良。【方法】以282份山西小麦品种为材料,在正常磷(0.2 mmol·L^(-1))、中度低磷(0.1mmol·L^(-1))和低磷胁迫(0.01 mmol·L^(-1))3个磷浓度条件下对苗期根部鲜重、茎叶部鲜重、植株鲜重、根部干重、茎叶部干重、植株干重,最大根长、总根长、根表面积、根体积、根直径和根尖数共12个形态指标进行考查,运用主成分分析、隶属函数分析及聚类分析等方法综合评价苗期不同品种的耐低磷特性,在此基础上,分析苗期性状演变趋势及生物量分配等特征,并利用全基因组关联分析挖掘小麦耐低磷位点。【结果】苗期不同性状对低磷的响应程度不同,磷浓度降低导致生物量分配策略发生变化,与根部生长情况比较,地上部生长受磷浓度变化影响小;磷浓度降低会抑制地上部生长,地上部干重和鲜重显著降低,而低磷促进了根系生长,根部干重和鲜重、最大根长、总根长、根体积和根尖数等指标显著增加。根据耐低磷综合D值与形态指标相关分析发现最大根长和根直径可作为苗期耐低磷的筛选指标,D值聚类分析筛选到晋麦46、晋麦61、有芒大红茎、红秃麦、红和尚、白壳红、白线麦、火烧头和白山麦共9份耐低磷品种。性状演变分析发现品种耐低磷能力没有受到直接选择。耐低磷能力随年代变化先降后升,2010年之前品种耐低磷能力呈下降趋势,2010年后品种耐低磷能力有所提升。关联分析检测到8个R^(2)>10%的稳定位点,其中,1A_545074550、2B_489279799、6A_166899658和6A_273060644未见报道。【结论】苗期最大根长和根直径可作为苗期耐低磷的筛选指标。通过综合评价山西小麦苗期耐低磷能力,筛选到9份耐低磷品种。在1A、2B和6A染色体上检测到4个与耐低磷相关的新位点。

两种棉花耐盐鉴定方法的综合评价与低酚棉种质系的耐盐性鉴定

【目的】探究陆地棉对人工海水和NaCl单盐胁迫的响应,评估人工海水模拟盐胁迫鉴定棉花耐盐性的可行性。【方法】以135份不同类型的陆地棉种质系为材料,比较人工海水和NaCl单盐胁迫对棉花种子萌发和幼苗生长的影响,结合主成分分析、隶属函数分析和聚类分析等方法对棉花材料的耐盐性进行综合评价,并通过田间试验对2种鉴定方法进行验证。【结果】2种盐胁迫下的鉴定结果仅有52.38%的一致性,鉴定结果存在较大差异。人工海水胁迫下的鉴定结果与田间试验鉴定结果呈极显著正相关关系,相关系数为0.720,NaCl胁迫下的鉴定结果与大田鉴定结果无显著相关关系。人工海水和NaCl胁迫处理下,105份低酚棉种质资源中表现为抗盐或耐盐的材料数量占比分别为21.90%和33.33%,其中鲁17和邯低酚29在2种胁迫下均表现出较强的耐盐性。【结论】使用与海涂地成分相似的人工海水模拟盐胁迫可以更加精确地鉴定棉花材料的耐盐性。低酚棉整体耐盐性较差,但不乏有耐盐性强的种质系,可用于培育耐盐的低酚棉新品种。

7个优质粳稻品种在寿光地区的种植鉴定

在潍坊市寿光市进行7个粳稻品种比较试验,对参试品种的农艺性状、产量、抗性及稻米品质表现进行汇总分析。结果表明,津原U99表现早熟、优质、丰产性较好,适于寿光试验区作优质米种植。圣稻22、圣香1826丰产性好、米质优良、中感稻瘟病,应加强稻瘟病的防治。津原U99、润农303、润农11表现抗稻瘟病,津原985高感稻瘟病,圣稻2620感稻瘟病。该试验为当地品种的合理选择提供了参考依据。

芝麻种质苗期耐盐性鉴定及耐盐材料筛选

土壤盐渍化是农业生产的主要限制因素,发展耐盐碱作物对盐碱地高效利用和提高土地增量具有重要意义。本实验以耐盐性差异明显的芝麻种质为试验材料,采用盆栽方法,设置0‰、5‰、8‰NaCl溶液3个处理,测定相对株高、存活率以及干/鲜重等指标,确立芝麻苗期耐盐性鉴定评价方法。实验结果显示随着盐浓度的增加,芝麻苗期各生长指标均呈下降趋势。8‰NaCl浓度下,相对苗/根鲜重、相对苗/根干重、相对株高和相对存活率变化范围分别为20.57%~49.12%,28.26%~48.76,8.17%~23.42%,6.46%~21.10%,10.91%~45.01%和6.83%~53.00%。采用隶属函数和主成分分析方法进行耐盐能力综合评价,各材料排序为‘G551’>‘G441’>‘LZ 1’>‘中芝11’>‘LZ 2’>‘JH1’>‘G358’>‘G452’。对126份芝麻种质以8‰NaCl为筛选浓度、以相对成苗率为筛选指标,进行了苗期耐盐性鉴定,通过聚类分析将参试材料划分为5大类,并筛选到耐盐芝麻种质9份。本研究为芝麻耐盐性鉴定和耐盐新品种选育提供了材料和技术支撑。

楸树组培苗内生菌分离鉴定与功能特性解析

研究旨在挖掘楸树组培苗内生菌资源,开发具有应用潜力的农业微生物菌群,从而促进组培苗快速生长和繁殖。利用选择性培养基对楸树组培苗内生菌进行分离鉴定。采用Ashby固体培养基初筛,测定液体培养基中有效氮浓度,评价内生菌固氮效果;通过Nbrip固体培养基初筛,测定液体培养基中可溶性磷浓度,评价内生菌解磷效果;测定内生菌对植物病原菌链格孢菌和葱柄锈菌的抑制效果。自楸树组培苗中分离获得24株内生菌,经形态和16S rRNA序列鉴定均为根瘤菌属的Rhizobium zeae。菌株NF6的固氮能力最强,其培养基中有效氮浓度达111.97 mg/L;菌株NF11的解磷效果最好,其培养基中可溶性磷浓度达1007.95 mg/L;多数内生菌对供试病原菌均有抑制效果,分别有6株和2株内生菌对链格孢菌和葱柄锈菌的抑制率超过20%。本研究获得了植物促生和生防效果的菌株资源,可为组培苗内生菌的潜在应用提供理论依据。

芜菁种质资源抗旱性鉴定与筛选

为系统评价芜菁幼苗的抗旱性,筛选抗旱种质,以40份芜菁种质为试验材料,采用苗期盆栽试验,设置干旱和正常浇水两种处理,测定芜菁幼苗形态指标、叶绿素含量、旱害指数、死亡率等19个抗旱性评价指标,并利用相关性分析、主成分分析、隶属函数法等对芜菁幼苗进行抗旱性综合评价和抗旱鉴定指标筛选。结果表明,与正常浇水处理相比,干旱胁迫降低了芜菁的株高、茎粗、叶长和叶宽、地上鲜质量和干质量、叶绿素含量等指标,但对地下部相关指标的影响有正负两种结果。根据综合评价结果,可将40份芜菁种质划分为3种类型,包括11份干旱敏感种质、5份抗旱种质、24份中度抗旱种质,其中抗旱性强的芜菁材料是B9,对干旱最为敏感的材料是B2;主成分分析结果表明,株高、叶长、叶宽、叶柄长、主根长、根体积、地上鲜质量、地下鲜质量、地下干质量、根冠比、旱害指数可作为芜菁幼苗抗旱性评价的重要指标。