古莲子与现代莲子ABA含量和SOD活性的比较研究

本研究选用种龄为580±70年的古莲子──太子莲,和与之亲缘相近的种龄为8年的现代哈尔滨莲,对比测定其脱落酸的含量及超氧物歧化酶活性,以期探讨距今已有几百年种龄的古莲仍能保持其活力、萌发、开花的现象与这两项生理指标的关系。实验结果表明,两种莲子的皮（果皮和种皮）ABA含量均很高,太子莲和哈尔滨莲分别为4.18 μg/g, 5.69 μg/g。SOD活性在莲子吸胀期和幼苗期两种莲子的子叶中差异不明显,而在胚和幼芽中,太子莲比哈尔滨莲分别高出50%和27%。基于以上结果,说明其胚中具有较强的抗逆性物质,利于保持其生命力。莲皮中高含量的ABA及胚中高活性的SOD有利于莲子的休眠和增强其抗逆性,并保持胚的生命力。     

莲子超氧物歧化酶的特性分析

比较了莲子、豇豆、绿豆、玉米、花生、菜心等6种植物种子的胚或胚轴超氧物歧化酶(SOD)的活性和热稳定性,其中莲子胚轴中SOD活性及耐热性最高。莲子胚轴粗提液中的SOD有Mn-SOD和Fe-SOD两种类型,而Fe-SOD耐高温。经100℃处理、硫酸铵沉淀、SephadexG-100凝胶过滤和DEAE-纤维素柱层析,获得纯化的耐热性强的超氧物歧化酶。纯化酶对KCN不敏感,活性受H     

莲子长寿机制的研究进展

莲( Nelumbo nucifera Gaertn.)为莲科、莲属多年水生宿根草本植物。莲子生命力极强,在自然条件下的泥碳层中能存活千年,甚至在极端高温、高湿条件下仍能保持较高的萌发活力。随着莲基因组测序与基因注释的完善,莲子长寿机制的相关研究取得了一定进展。本文对莲子的结构形态、保护系统和基因组特性方面的研究进展进行了综述,阐明莲子的长寿机制,对后续研究方向进行了展望。     

莲子长寿机制的研究进展

莲（Nelumbo nucifera Gaertn.）为莲科、莲属多年水生宿根草本植物。莲子生命力极强,在自然条件下的泥碳层中能存活千年,甚至在极端高温、高湿条件下仍能保持较高的萌发活力。随着莲基因组测序与基因注释的完善,莲子长寿机制的相关研究取得了一定进展。本文对莲子的结构形态、保护系统和基因组特性方面的研究进展进行了综述,阐明莲子的长寿机制,对后续研究方向进行了展望。     

莲子Fe-SOD的提取及其耐高温能力的初探

通过对莲子中超氧化物歧化酶(Super Oxide Dimutase,SOD)进行分离提纯,证实其是Fe-SOD,并观察Fe-SOD的耐热性,为SOD的提取和应用开辟了新的思路【。方法】以热变性与有机溶剂沉淀联合法分离提纯莲子Fe-SOD;利用Fe-SOD活性受H2O2的抑制而不受氰化物的抑制的特性来鉴定;设置不同的温度观察提取额莲子SOD的耐热性。【结果】莲子提取酶液活性为90.522U/ml,SOD酶液对邻苯三酚自氧化的抑制率为96.3%。莲子SOD活性受H2O2的抑制而不受氰化物的抑制。在75℃时保温30min后,酶活力仍然保留60%以上,在100℃保温30min时酶活力保留35%。【结论】以热变性与有机溶剂沉淀联合法分离提纯莲子SOD并鉴定其为耐热性Fe-SOD。     

两种生态型空心莲子草对莲草直胸跳甲发育和繁殖的影响

【目的】评价空心莲子草Alternanthera philoxeroides 2种生态型食物对莲草直胸跳甲Agasicles hygrophila生长发育和繁殖的影响。【方法】建立莲草直胸跳甲在水生型和旱生型空心莲子草上的实验种群两性生命表。【结果】2种生态型空心莲子草对莲草直胸跳甲2龄和3龄幼虫的历期、产卵前期、产卵期、雌虫寿命、雄成虫寿命和繁殖力的影响无显著差异,但取食水生型空心莲子草的莲草直胸跳甲具有较短的蛹历期（6.28 d）、较高的幼虫期存活率（99.00%）和较高的成虫前期存活率（95.00%）;取食旱生型空心莲子草的莲草直胸跳甲在内禀增长率和周限增长率都显著低于水生型食物,但莲草直胸跳甲的净增殖率（R_0）和平均世代周期（T）在旱生型和水生型食物间并无显著差异。【结论】与旱生型空习莲子草相比,水生型空心莲子草是莲草直胸跳甲的较适宜食物,但旱生型空心莲子草并不显著影响莲草直胸跳甲的发育和繁殖。     

莲种胚在温度胁迫下的逆境生理研究

为明确莲种胚对不同温度胁迫的耐受能力,探索莲种胚细胞在逆境胁迫下的生理响应规律,该研究以成熟莲子为材料,从形态学、抗性生理和抗氧化相关基因表达定量3个层面进行了研究。结果表明:(1)莲子对于高温与超低温具有较好的胁迫耐受能力,经70 ℃高温与-196 ℃超低温处理后,其发芽率和种芽长相比对照组无显著变化; 80 ℃及以上的高温处理会使莲种胚吸水萌发迟缓,发芽率降低50%及以上,种芽萌发变慢。(2)高温处理后,莲种胚细胞中抗氧化酶活性随吸水萌发过程呈上升趋势,非酶促抗氧化剂含量下降,细胞膜脂过氧化程度逐渐减轻,质膜完整性有所恢复。(3)高温处理下,莲种胚氧化应激相关基因(DHN Rab18、Cu/Zn SOD、Mn SOD、POD41、POD73、CAT1、GR、APX)积极参与胁迫响应,出现不同程度的上调表达,100 ℃处理组中DHN Rab18、Cu/Zn SOD、POD41、GR与APX上调表达幅度较大。综上结果认为,莲种胚具有良好的高温与低温胁迫耐受性,在不同温度胁迫下抗氧化系统与抗逆保护类蛋白对维持莲种胚的细胞活力可能发挥重要保护作用。     

白刺花胚性愈伤组织诱导及体细胞胚发生和萌发

探讨不同因素对白刺花下胚轴、子叶2种外植体胚性愈伤组织诱导及体细胞胚发生和萌发的影响。以B5和MS为基本培养基,研究2,4-D、6-BA和TDZ对白刺花下胚轴和子叶胚性愈伤组织的诱导;在MS培养基上添加不同浓度2,4-D,研究胚性愈伤组织增殖情况;采用ABA,探究对体细胞胚发生的影响。结果表明:下胚轴比子叶更易诱导胚性愈伤组织,筛选出2种外植最佳的胚性愈伤组织诱导培养基均为MS+2.0 mg/L 2,4-D+0.5 mg/L TDZ+0.5 mg/L 6-BA,胚性愈伤组织诱导率分别为77.3%和41.0%。15.0 mg/L ABA、0.2 mg/L 2,4-D和2.0 mg/L 6-BA有利于体细胞胚发生,1/3MS+0.2 mg/L NAA+0.1 mg/L 6-BA+2.0 g/L活性炭+25 g/L蔗糖+7 g/L琼脂的培养基可使体细胞胚萌发率达80%以上,再生植株移栽成活率高达90%。白刺花外植体种类及培养基类型均会影响胚性愈伤组织的诱导,其中下胚轴诱导效果优于子叶;MS培养基较适合启动细胞脱分化形成愈伤组织,2,4-D对胚性愈伤组织的增殖保持有调控作用,ABA有利于体细胞胚的发生。     

莲子食用价值研究进展

莲（Nelumbo nucifera Gaertn.）为莲科莲属多年生水生双子叶被子植物,在世界上具有广泛的分布。莲的用途广泛,其各个组织器官都可以食用或药用。莲的种子即莲子是一种广受欢迎的食物,既可鲜食也可加工成各种莲子产品后食用。莲子中含有丰富的淀粉、蛋白质、多糖、氨基酸、矿质元素、酚类、生物碱等成分,既能食用,也具有保健价值。前人对莲子的生长发育及营养价值已经开展了较多的研究,在此基础上,该文主要针对莲子的营养成分、保健功效和加工工艺进行综述,并对莲子的开发应用前景和限制因素进行总结和展望。     

莲子食用价值研究进展

莲(Nelumbo nucifera Gaertn.)为莲科莲属多年生水生双子叶被子植物,在世界上具有广泛的分布。莲的用途广泛,其各个组织器官都可以食用或药用。莲的种子即莲子是一种广受欢迎的食物,既可鲜食也可加工成各种莲子产品后食用。莲子中含有丰富的淀粉、蛋白质、多糖、氨基酸、矿质元素、酚类、生物碱等成分,既能食用,也具有保健价值。前人对莲子的生长发育及营养价值已经开展了较多的研究,在此基础上,该文主要针对莲子的营养成分、保健功效和加工工艺进行综述,并对莲子的开发应用前景和限制因素进行总结和展望。     

Comparative Analyses in Lotus : The Cytogenetic Map of Lotus uliginosus Schkuhr

A comparative cytogenetic map was built for Lotusuliginosus (2n = 12), expanding previous analyses that revealed intra- and interspecific chromosomal rearrangements in the model legume L. japonicus, L. filicaulis, and L. burttii. This species is positioned in a sister clade of the previously-mapped species and is proposed as one of the progenitors of L. corniculatus, the main forage crop of the genus. The cytogenetic map allowed the location of 12 genomic regions to be compared between these species. A high macrosynteny was revealed, but it was interrupted by a translocation involving chromosomes 3 and 5, a new rearrangement for the genus. Also, a transposition on chromosome 2 was found in L. japonicus 'Miyakojima'. Furthermore, changes in the number, size, and position of rDNA sites were observed, as well as an intraspecific size heteromorphism of the 5S rDNA site on L. uliginosus chromosome 6. The karyotype differences observed are proportional to the phylogenetic distance among these species.     

Photoperiod and photosynthetic capacity in Lotus scoparius

Abstract Leaves of Lotus scoparius Nutt., a Mediterranean-climate shrub, exhibited higher photosynthetic capacities when grown under winter (10/14 h, day/night) than summer (14/10 h) photo-periods, even though total daily photon irradiance was higher under summer photoperiods. Photosynthetic dependence on natural variations in photo-period, such that activity was higher under photo-periods associated with expected precipitation, may be a more dependable environmental parameter than total irradiance in temperate habitats with winter-spring precipitation patterns and where seasonal cloudiness may cause total daily irradiance levels to be highly variable.     

莲SRAP-PCR反应体系的优化与建立

以中国古代莲(Nelumbo nucifera)和美洲黄莲(N.lutea)为材料,利用单因素分析法对影响莲SRAP-PCR扩增效果的模板、Mg2+、dNTP、Taq DNA聚合酶、引物浓度进行了探索和研究.获得了能稳定扩增莲基因组的SRAP-PCR最佳10 μL反应体系:模板DNA浓度为50 ng、1μL10×Buffer、MgCl2浓度为2 mmol/L、dNTPs浓度为0.2 mmol/L、Taq DNA聚合酶浓度为0.75 U、正反向引物浓度均为0.8μmol/L.为检测该优化体系的稳定性,进一步选取16对引物组合对88份花莲核心种质进行PCR扩增,获得了183条清晰的谱带,其中165条具有多态性,比率为90％,说明建立的莲SRAP反应体系是稳定可靠的.莲SRAP-PCR反应体系的优化和建立,为利用SRAP标记技术深入开展莲的遗传多样性评价、遗传连锁图构建和分子辅助育种等研究提供成熟的技术体系支撑.     

Genome and Chromosome Dimensions of Lotus japonicus

Lotus Japonicus , Miyakojima MG-20 and Gifu B-129. The genome sizes of Miyakojima and Gifu were determined as 472.1 and 442.8 Mbp, respectively. Both the accessions were diploid (2n=12) and six chromosomes were identified and characterized based on the condensation patterns and the locations of rDNA loci. The obvious polymorphism observed in the genome size and the chromosome morphology between the two accessions, revealed specific accumulation of heterochromatin in Miyakojima or elimination in Gifu. The chromosomes L. japonicus were numbered according to their length. A quantitative chromosome map was also developed by the imaging methods using the digital data of the condensation pattern. 45S rDNA loci were localized on chromosomes A and F, and 5S rDNA locus was localized on chromosome A by fluorescence in situ hybridization (FISH). Identification of the chromosome and genome sizes and development of the quantitative chromosome map represent significant contribution to the L. japonicus genome project as the basic information. Received 29 August 2000/ Accepted in revised form 17 October 2000     

莲藕研究进展

综述了莲藕在分类、生长发育、遗传育种、组织培养、生理学特性等方面的研究进展.     

Petal Development in Lotus japonicus

Previous studies have demonstrated that petal shape and size in legume flowers are determined by two separate mechanisms, dorsoventral (DV) and organ internal (IN) asymmetric mechanisms, respectively. However, little is known about the molecular mechanisms controlling petal development in legumes. To address this question, we investigated petal development along the floral DV axis in Lotus japonicus with respect to cell and developmental biology by comparing wild‐type legumes to mutants. Based on morphological markers, the entire course of petal development, from initiation to maturity, was grouped to define 3 phases or 13 stages. In terms of epidermal micromorphology from adaxial surface, mature petals were divided into several distinct domains, and characteristic epidermal cells of each petal differentiated at stage 9, while epidermal cells of all domains were observed until stage 12. TCP and MIXTA‐like genes were found to be differentially expressed in various domains of petals at stages 9 and 12. Our results suggest that DV and IN mechanisms interplay at different stages of petal development, and their interaction at the cellular and molecular level guides the elaboration of domains within petals to achieve their ideal shape, and further suggest that TCP genes determine petal identity along the DV axis by regulating MIXTA‐like gene expression.     

The origin of Lotus corniculatus

Summary Earlier students of the origin of Lotus corniculatus suggested that this tetraploid species arose as an autotetraploid of the closely related diploid species L. tenuis or L. alpinus. More recent studies suggested that L. alpinus and L. japonicus could be ancestral forms. The present study of tannin content, phenolic content, cyanide production, morphology, cytogenetics, Rhizobium specificity and self-incompatibility in the corniculatus group virtually excludes the possibility that L. corniculatus could have arisen through autopolyploidy of L. tenuis or L. alpinus, and suggests that L. corniculatus arose through hybridization of L. alpinus and/or L. tenuis (probably as female parent) with L. uliginosus (probably as male parent), followed by chromosome doubling in the hybrid.     

Physiological and Anatomical Basis of Differential Tolerance to Soil Flooding of Lotus corniculatus L. and Lotus glaber Mill

Lotus corniculatus L. and Lotus glaber Mill. are warm-season legume species adapted to many kinds of environmental stress, including flooding conditions, whereas other popular forage legumes, like alfalfa or white clover, cannot thrive. This study evaluates the relationship between root aerenchyma, water relations and leaf gas exchange and the differential tolerance to soil flooding of L. corniculatus and L. glaber. Adult plants of these species, established independently in grasslands mesocosms, were subjected to 40 days of early spring flooding at a water depth of 6 cm. Both species presented constitutive aerenchyma tissue in the roots. Under flooding conditions, this parameter was 26.2% in L. glaber and 15.3% in L. corniculatus. In addition, flooded plants of L. glaber presented a leaf biomass 47.5% higher above water while L. corniculatus showed a leaf biomass 59.6% lower in the same layer, in comparison to control plants. Flooded plants of L. glaber maintained the stomatal conductance (g _s) and transpiration rate (E) for 25 days, although these parameters reduce slightly to 40–60% in comparison to controls after 40 days of flooding. In this species, a reduction in photosynthesis (A) in flooding conditions was detected only on the last day of measurement. In L. corniculatus, the same parameters (g _s, E and A) were affected by flooding since day 18 of treatment, and values reached 25–40% in comparison to control plants after 40 days of flooding. Flooding did not affect above-ground biomass in L. glaber; while in L. corniculatus, above-ground biomass was 35% lower than in control plants. Our results confirmed that L. glaber is more able to cope with flooding stress than L. corniculatus, even in the presence of natural competitors. On the whole, this experiment provides information that can aid in the identification of anatomical and physiological parameters associated with flood-tolerance in this forage legume species, with economic potential for the agricultural areas subject to periodic flooding.     

Genome Analysis of Lotus japonicus

Lotus japonicus , a model legume plant, was reviewed and compared with Medicago truncatula and soybean. Several mutant libraries are being analyzed, focusing on the nodulation mechanism. The first plant nodulation gene nin was cloned by Ac-transposon tagging. Soybean remains as the most studied legume, especially in relation to the disease resistance genes. However, Lotus japonicus offers several advantages for molecular genetics, and the remained lackings were recently filled up, namely 1) an appropriate crossing partner for Gifu, accession Miyakojima, was proposed for its 4% polymorphism and smooth recombining ability; 2) a genome library with long inserts, average of 140 kb, and 8.2 genome equivalents of library size, has been established; and 3) the rather low polymorphic rate between Gifu and Miyakojima can be overcome with the HEGS (High Efficiency Genome Scanning). With this infrastructure, positional cloning of the causative genes of several mutant libraries will be accomplished in a short term. Genome sizes of L. japonicus acc. Gifu and Miyakojima were determined with high accuracy, to be 494±0 MB and 512±1 MB, respectively. The feasibility of constructing a physical map of the entire genome, for functional genomics, was discussed. Received 5 September 2000/ Accepted in revised form 11 October 2000