烟草含钾量的基因型差异及钾高效品种筛选

【目的】高含钾量是优质烟叶的一项重要指标。比较不同烟草品种的含钾量及其对施用钾肥的反应,为筛选高钾基因型烟草品种提供基础。【方法】以 93 份烟草种质资源为研究对象,在凉山州进行连续两年的大田试验。设置常规钾 (K₂O = 300 kg/hm2) 与低钾 (K₂O = 150 kg/hm2) 两个水平,成熟期测定烟叶含钾量,以聚类分析将烟草分类,并分析其在不同叶位间的基因型差异。【结果】施钾量影响烟草上、中、下部叶片钾含量,常规钾水平下的烟叶含钾量高于低钾水平,常规施钾量下的上、中、下部烟叶含钾量分别为低钾水平下的 1.13、1.14、1.15 倍 (2014 年) 和 1.10、1.25、1.35 倍 (2015 年) 。将烟叶含钾量进行聚类分析,供试材料被划分为高钾型、普通型和低钾型 3 类,并筛选获得了典型材料。高钾型烟草的上、中、下部烟叶含钾量均显著高于普通型及低钾型烟草材料。常规施钾水平下,高钾型烟草的上、中、下部烟叶含钾量分别是低钾型的 1.50～1.92、1.54～2.52、1.31～2.36 倍;低钾水平下分别为 1.27～1.93、1.66～2.24、1.72～1.73 倍。【结论】高钾基因型烟草上、中、下部烟叶的含钾量均显著高于普通型和低钾型;普通型上部叶的含钾量与低钾型烟草之间无显著差异,中、下部烟叶含钾量普通型显著高于低钾基因型。通过两年田间试验筛选获得了 6 份高钾型烟草材料,包括嘎吉红大、长叶红大、达白 1 号、达白 2 号、MFZS、930032-7,可应用于烟叶生产,亦可为富钾基因型品种选育提供育种亲本材料。     

蕺菜属植物富钾基因型的筛选

在低钾土壤培养和营养液培养的条件下,采用植株含钾量、吸钾速率和钾素利用率并结合植株根系形态特征,对蕺菜属(Houttuynia Thunb.)16份不同基因型材料的富钾能力进行筛选.结果表明,峨眉蕺菜W01-86以及蕺菜W01-34和W01-71在低钾土壤培养和溶液培养时植株含钾量分别高于9.0%,5.50%,吸钾速率大于1.50μmol/(g·h).低钾土壤培养和溶液培养时的钾素利用率分别高于2.50,0.30g/g,为富钾基因型;W01-4和W01-99低钾土壤培养和溶液培养时的植株含钾量分别低于8.5%,5.0%,吸钾速率小于0.65μmol/(g·h),低钾土壤培养和溶液培养时的钾素利用率分别低于2.00,0.30 g/g,为低钾基因型.     

籽粒苋根际土壤及根系分泌物对矿物态钾的活化作用

通过大田和模拟试验等方法 ,研究了籽粒苋根际土壤及根系分泌物对矿物态钾的活化作用 ,研究结果表明 :(1)籽粒苋根际土壤的速效钾含量较非根际土增加了 1.7倍 ,缓效钾 (K)的含量也提高了 5 5 .9% ;(2 )用籽粒苋根际土壤处理后的花岗岩粉末 ,其速效钾和缓效钾含量均较对照有所增加 ,增幅分别为 2 .8%～ 2 4.7%和 15 .7%～ 44 .7% ;用籽粒苋根际土壤处理后的紫色土 ,其速效钾和缓效钾含量较对照分别增加了 18.5 %和 11.1% ;(3 )通过对y值的综合贡献率计算可知 ,不同籽粒苋模拟根系分泌物对花岗岩粉末中矿物态钾的活化能力大小依次为 :草酸 >蔗糖 >核酸 >乳酸 >柠檬酸。     

水稻钾素营养的根际效应

关于淹水条件下根际效应的研究迄今很少。而淹水土壤的根际环境与早作土壤十分不同。     

烟草根际土壤中解钾细菌的分离与多样性分析

土壤中含有丰富的钾元素,但主要以缓效态形式存在于钾长石或云母等硅酸盐矿物中,不能被作物直接吸收利用。解钾微生物能溶解硅酸盐矿物中的钾,提高土壤中作物可利用钾的含量,有望缓解我国钾肥短缺的现状。本研究利用选择性培养基,从烟草根际筛选钾细菌,基于16S rDNA序列分析烟草根际土壤解钾细菌的多样性,通过测定解钾细菌的解钾效能及对烟草的促生作用,筛选有应用潜力的优良解钾细菌菌株。结果表明,从四川、湖北和山东烟区烟草根际土壤分离获得的27株解钾细菌,在解钾固体培养上溶钾圈直径为0.11~0.30 cm。16S rDNA序列分析表明,烟草根际土壤解钾细菌主要包括变形菌门γ亚群(Gammaproteobacteria,85.18%)、变形菌门α亚群(Alphaproteobacteria,3.70%)、变形菌门β亚群(Betaproteobacteria,3.70%)、放线菌门(Actinobacteria,3.70%)和拟杆菌门(Bacteroidetes,3.70%),其中克雷伯菌属(Klebsiella)为优势菌属(66.67%)。27个菌株均有一定的解钾能力,解钾活性为0.59~4.40 mg.L–1。参试菌株均对烟草有一定的促生作用,利用解钾细菌菌液处理烟株20 d后,与对照相比,株高增加0.97%~38.64%,最大叶长增加4.40%~31.02%。本研究筛选出的菌株XF11、GM2、JM19和GL7具有较高的解钾活性和促进植物生长的能力,展现了良好的应用潜力。     

铬处理下超富集植物李氏禾根际溶解氧时空分布特征

植物根系泌氧能改变土壤氧化还原电位,影响重金属形态及生物有效性,是重金属污染土壤植物修复效率的重要影响因素。本文基于平面光极原位高分辨技术,在0、50、100 mg/kg等3个铬浓度下研究了铬超富集植物李氏禾根际溶解氧的时空分布特征。结果表明,李氏禾根际土壤中溶解氧浓度较高的热区集中于根系周围区域,在根尖位置溶解氧浓度较高。根际溶解氧含量显著高于非根际土壤,且距离根部越远溶解氧平均含量越低,其中100 mg/kg铬处理组李氏禾根部中心位置土壤溶解氧浓度为距离中心位置5 mm处土壤溶解氧浓度的1.45倍。在8天的拍摄周期中,对照组根部中心位置溶解氧浓度最高达77.2%,显著高于50 mg/kg铬处理组的50.2%和100 mg/kg铬处理组的42.3%。此外,3个铬浓度下李氏禾根际溶解氧浓度都呈现先升高后降低的规律,第4天达到最高值。铬处理下李氏禾根际溶解氧浓度明显下降,这可能是李氏禾为避免根际富氧环境将Cr(III)氧化为毒性更强Cr(VI)的保护性行为。     

我国南方镭污染区优势植物及根际微生物分析

为探索我国南方中低水平镭污染土壤环境中优势植物对²²⁶Ra的富集规律及其根际微生物特征,对属于中亚热带湿润型季风气候区的南方典型铀矿区进行了野外实地样方调查,采集该地区优势植物和土壤,分析物种优势度、土壤镭污染水平、植物对²²⁶Ra的转移和富集特征、植物根际微生物特征。结果表明,现场共筛选出15种优势草本植物,以苏丹草（Sorghum sudanense）的生物量最大,富集系数和转运系数分别为0.17、0.45;采样区²²⁶Ra的平均浓度为211 Bq·kg^-1;土壤中存在大量的变形菌门（Proteobacteria）、子囊菌门（Ascomycota）等微生物,且不同的植物根际有特定的微生物类群富集,在放射性环境治理和修复、形成植物-微生物联合修复组合方面具有应用潜力。本研究结果为后期筛选原位治理土壤放射性污染的植物-微生物联合修复技术提供了依据。     

小麦根际解钾微生物与土壤钾含量、钾素利用率及根系活力的关系

[目的]探讨肥料施用方式和施钾量对土壤不同形态钾含量及小麦根系活力的影响,以期为提高土壤钾素利用效率提供技术支持.[方法]2018—2020年连续两年,采用裂裂区设计,主区为肥料(A):设20％ 有机肥(鸡粪)+80％ 氮肥(A1),100％ 氮肥(A2)2个水平;副区为施钾量(B):设不施钾(B1)、减量施钾80 k...     

根分泌物对根际微生物生态分布的影响

本文从根分泌概念着手 ,依据近 2 0年来国内外有关根分泌研究的一些成果 ,就根分泌物的概念、产生机制进行了综合论述 ,并重点讨论了植物根分泌物对根际微生物代谢、生态分布、病原微生物抑制作用的影响以及土壤环境对根分泌物的影响。     

湿地植物铅的富集特征及根际铅移动性的影响因素研究

【目的】揭示湿地植物铅的富集特征及根际铅移动性影响因素的作用机理,为人工湿地修复重金属污染水体提供理论指导和依据。【方法】通过根箱法研究了五种挺水湿地植物 (大叶皇冠草、黑籽荸荠、圆币草、草龙、小婆婆纳) 根际 pH、氧化还原电位 (Eh)、Fe2+ 和 Fe3+ 浓度、铅 (Pb) 的化学形态及移动性的变化。【结果】与非根际相比,五种植物根际pH下降,Fe2+ 和 Fe3+ 浓度显著下降,Eh显著升高,Pb的移动性显著降低 (P<0.05)。与非根际相比,根际pH下降幅度为 0.1～0.4个单位,根际Fe2+和 Fe3+浓度下降幅度为0.6～2.7 mmol/kg。土壤中铅的存在形态主要以残渣态为主 (36.39%～47.54%),其次是铁锰氧化物结合态 (30.16%～41.64%)、有机质结合态 (8.85%～15.08%) 和碳酸盐结合态 (6.89%～12.46%)。五种湿地植物根际Pb的移动性降低的主要原因是根际碳酸盐结合态Pb含量显著下降,其中大叶皇冠草受根际pH、Eh、Fe3+和Fe2+的影响导致其根际Pb移动性降低效应最为显著。【结论】五种供试植物Pb主要分布在根部;根表富集的铁膜数量显著高于锰膜数量;供试植物根际Fe3+含量与Pb的移动性因子呈极显著正相关,湿地植物根系铁氧化能力对降低其根际重金属的移动性有重要作用。本研究为人工湿地修复重金属污染水体提供了有力的理论依据。     

EDDS对印度芥菜Cu积累的影响及与P-ATPase的关系研究

通过水培的方法研究了可降解螯合剂EDDS对印度芥菜对Cu积累的影响,分析了根系中与Cu主动排出有关的P型ATPase的活性及其基因表达。结果表明:根系中Cu的积累量随外界浓度的升高而升高,但Cu在茎杆与叶片中的积累量则变化不大。随着外加EDDS浓度的增加,根、茎、叶中的Cu的积累量均出现下降的趋势。上述结果表明,根系以Cu离子为主要的吸收形式,而不是EDDS-Cu。通过对印度芥菜根系细胞膜上P型ATPase活性及基因表达分析后发现,不加EDDS时,随着外界Cu浓度的升高,ATPase活性增强,而当Cu达到16μmol L-1时出现降低的趋势。但是,ATPase活性随着外加EDDS的浓度增加而降低,这是因为EDDS降低了外界的Cu活度。RT-PCR分析结果表明,该ATPase的基因(BjHMA)在转录水平上的表达与活性变化一致。由于P型ATPase的作用是将Cu排出细胞,因此上述结果说明,其活性大小以及转录水平的变化受到外界Cu离子活度的影响,在一定的范围内可以调节植物对Cu的积累。     

Cadmium bioavailability to Nicotiana tabacum L., Nicotiana rustica L., and Zea mays L. grown in soil amended or not amended with cadmium nitrate

Summary Mature (flowering) tobacco (Nicotiana tabacum cv. PBD6, Nicotiana rustica cv. Brasilia) and maize (Zea mays cv. INRA 260) plants were grown in an acid sandy-clay soil, enriched to 5.4 mg Cd kg^–1 dry weight soil with cadmium nitrate. The plants were grown in containers in the open air. No visible symptoms of Cd toxicity developed on plant shoots over the 2-month growing period. Dry-matter yields showed that while the Nicotiana spp. were unaffected by the Cd application the yield of Z. mays decreased by 21%. Cd accumulation and distribution in leaves, stems and roots were examined. In the control treatment (0.44 mg Cd kg^–1 dry weight soil), plant Cd levels ranged from 0.4 to 6.8 mg kg^–1 dry weight depending on plant species and plant parts. Soil Cd enrichment invariably increased the Cd concentrations in plant parts, which varied from 10.1 to 164 mg kg^–1 dry weight. The maximum Cd concentrations occurred in the leaves of N. tabacum. In N. rustica 75% of the total Cd taken up by the plant was transported to the leaves, and 81% for N. tabacum irrespective of the Cd level in the soil. In contrast, the Cd concentrations in maize roots were almost five times higher than those in the leaves. More than 50% of the total Cd taken up by maize was retained in the roots at both soil Cd levels. The Cd level in N. tabacum leaves was 1.5 and 2 times higher at the low and high Cd soil level, respectively, than that in N. rustica leaves, but no significant difference was found in root Cd concentrations between the two Nicotiana spp.Cd bioavailability was calculated as the ratio of the Cd level in the control plants to that in the soil or as the ratio of the additional Cd taken up from cadmium nitrate to the amount of Cd applied. The results showed that the plant species used can be ranked in a decreasing order as follows: N. tabacum > N. rustica > Z. mays.     

Effect of pre-incubated sawdust-based cowdung on growth and nutrient uptake of Zea mays (L.) and on soil chemical properties

Summary A greenhouse soil culture experiment was set up to evaluate the effect of pre-incubation time (0, 2, 4, 6 weeks) of sawdust-based cowdung, prior to use, on the growth, dry-matter yield, and uptake of nutrients by Zea mays (L). The chemical properties of the soil (an Alfisol) were examined after the various treatments. The results indicated that incubation of cowdung for 4 weeks before planting time enhanced the growth and dry-matter yields of maize. Soil pH increased with the length of incubation while organic-C contents and cation exchange capacity remained unaffected. The length of pre-incubation enhanced the uptake of N and P but did not affect the uptake of K, Ca, Mg, and Na.     

Genetic Diversity among Syrian Cultivated and Landraces Wheat Revealed by AFLP Markers

Genetic diversity among some important Syrian wheat cultivars was estimated using Amplified Fragment Length Polymorphism (AFLP) markers. Five Triticum aestivum L. and 10 Triticum turgidum ssp. durum were analyzed with 11 EcoRI–MseI primer pair combinations. Of the approximately 525 detected AFLP markers, only 46.67% were polymorphic. Cluster analysis with the entire AFLP data divided all cultivars into two major groups reflecting their origins. The first one contained T. aestivum L. cultivars, and the T. turgidum ssp. durum cultivars and landraces were grouped in the second. Narrow genetic diversity among all cultivars was detected with an average genetic similarity of 0.884. The lowest similarity index (0.9) was found between Cham5 and Hamary (durum wheat), whereas this value was 0.93 between Salamony and Bouhouth 4 (T. aestivum L.). The narrow genetic diversity level indicates that these genotypes could be originated from the same source. AFLP analysis provides crucial information for studying genetic variation among wheat cultivars and provides important information for plant improvement.     

A forage grass and small grain legume plant collecting expedition in South East Poland, 1990

Summary The Plant Genetic Resources Unit (PGRU) of the Institute of Grassland and Environmental Research, Welsh Plant Breeding Station (IGER, WPBS), UK, and the Plant Genetic Resources Section of the Plant Breeding and Acclimatization Institute (PBAI), Poland, carried out a joint collecting expedition in Poland between 25 August and 7 September 1990. The expedition was unique in that it was the first time that vegetative sampling had been applied to the perennial forage grass and legume populations of south east Poland. The expedition focused on seminatural vegetation in agriculturally managed situations and detailed collection site data on management systems was obtained from landowners.Samples were collected from 62 sites. Vegetative collections of Lolium spp. (37 populations) and Trifolium spp. (56 populations), and seed collections of Festuca spp. (32 populations) were made by the IGER team (Table 2). The PBAI team made 59 separate seed collections, mainly of Leguminosae.The expedition covered four geographical subregions of south east Poland. (See Fig. 1). These were the Nizina Mazowiecka south of Warszawa, the Wyzyna Malopolska with the town of Kielce at its centre and the Beskidy Zachodnie and Beskidy Wschodnie regions of the Carpathian mountains.A diverse range of habitats was sampled covering a broad range of altitude agricultural management systems and ecological conditions. Polish agriculture is faced with the problems of a rapid orientation to a market economy and it is likely that the diverse range of habitats encoutered will be reduced as agricultural practices change. This will lead to genetic erosion of the unique forage grass and legume populations to be found in Poland.Abbreviations ECP/GR European Co-operative Programme on Crop Genetic Resources - IGER Institute of Grassland and Environmental Research - PBAI Plant Breeding and Acclimatization Institute - PGRU Plant Genetic Resources Unit - WPBS Welsh Plant Breeding Station     

机械损伤对烤烟植株氮素吸收及体内烟碱含量的影响

采用砂培和营养液培养方法,研究了在营养生长阶段切除顶芽和叶片损伤对烟株生长、体内烟碱浓度、氮浓度及吸氮量的影响。结果表明,切除顶芽导致烟株体内烟碱浓度和含量显著增加。叶片损伤也能增加体内的烟碱浓度,且损伤二次比损伤一次的效果更为明显,说明叶面损伤对烟株体内烟碱合成的影响具有累积效应。但叶面损伤对烟株体内烟碱合成的影响小于打顶处理。切除顶芽和叶面损伤对烟株体内的氮浓度及吸氮量均无显著影响,但显著提高了烟株体内单位氮素产生烟碱的能力。试验结果还表明,机械损伤刺激烟株体内烟碱的合成,烟碱增加与氮素吸收无直接关系。     

不同化感潜力水稻品种对低钾的生理与分子响应

选择国际公认的化感水稻品种“P1312777”和非化感水稻品种“Lemont”为材料,在K元素为5mg&#183;L^-1（低K）和40mg&#183;L^-1（正常K）2个水平的营养液中培养,通过水稻形态学指标（根长、株高、根冠比和生物量）、生理生化指标（SOD、POD、CAT、根系活力及植株中N、P、K含量）,评价不同化感潜力水稻品种对低K胁迫的生理响应,并采用实时荧光定量PCR（Realtime Fluorescent Quantitative PCR,FQ-PCR）,分析了低K胁迫下水稻根和叶中与N、P、K吸收利用相关的12个关键酶的基因表达差异。结果表明,低K促进了化感水稻“P1312777”根的生长,根冠比加大,生物量增加,但对株高的影响不显著;而该条件下非化感水稻“Lemont”的上述指标均受到不同程度的抑制。低K对两种水稻的保护酶系（SOD、POD、CAT）和根系活力均有一定程度的抑制作用,植株中N、P、K含量降低,但非化感水稻“Lemont”受抑制的程度远大于化感水稻“P1312777”。FQ-PCR检测结果表明,低K胁迫下两种水稻根、叶中的12个关键酶的基因均呈现上调表达,而化感水稻“P1312777”的基因表达上调倍数均明显大于非化感水稻“Lemont”。低K胁迫下两种水稻品种的形态学差异、生理与分子响应均表明,化感水稻“P1312777”比非化感水稻“Lemont”具有更强的适应K匮乏的能力。     

小麦/玉米苗期磷累积量对介质供磷水平反应的差异

小麦和玉米苗期是磷素营养的关键期和敏感期,研究两种作物苗期对介质供磷反应,可为合理施用磷肥提供参考.试验设缺磷对照、低磷胁迫、中等磷胁迫和正常供磷(P2O5含量分别为0、0.05 mmol·L-1、0.3 mmol·L-1和0.5 mmol·L-1) 4种磷水平,选取小麦\"小偃22号\"、\"兰考4号\"和玉米\"屯玉65号\"、\"户单4号\"为指标作物,用营养液培养法研究小麦、玉米苗期磷累积量对介质不同供磷水平的反应差异.结果表明,不同介质供磷水平下,两种作物苗期磷累积量显著不同且因作物类型、基因型、器官及测定时期不同而异.总体而言,介质供磷后,苗期早期生长阶段(出苗后25 d以前),小麦的介质最佳供磷水平较玉米高;苗期后期(出苗后40～50 d),小麦和玉米最佳供磷水平一致.如果以低磷胁迫作为对比进行分析,玉米苗期整株磷累积量对介质供磷的敏感性比小麦强;从不同基因型来看:\"兰考4号\"对介质供磷的敏感性强于\"小偃22号\",\"屯玉65号\"和\"户单4号\"基本一致.缺磷条件下小麦较玉米磷效率高,供磷条件下玉米较小麦高;但不同基因型间规律性较差.