Genetic diversity of the wild Asian lotus (Nelumbo nucifera) from Northern China

Asian lotus(Nelumbo nucifera Gaertn.)is an aquatic plant with ornamental,cultural,economic,and ecological values.China has abundant germplasm resources of Asian lotus.However,in many areas,the wild Asian lotuses have been destroyed and the germplasms is now facing extinction.In addition,the knowledge of the genetic diversity of the wild Asian lotus in China is poor.To identify and protect the germplasms of Chinese wild Asian lotus,eleven genomic-SSR primers,three EST-SSR primers,and three chloroplast DNA primers were used to investigate the genetic diversity among 69 samples of wild Asian lotus from 25 locations in northern China.The genetic diversity of 27 samples of wild Asian lotus from southern China and other countries,the ancient Asian lotus,Asian lotus cultivars from China,and Asian-American hybrids was also compared.The genetic diversity of the wild Asian lotus from northern China was characterized as medium,and themean values of observed heterozygosity(Ho)and expected heterozygosity(He)were 0.087 and 0.552,respectively.Based on a UPGMA dendrogram and STRUCTURE analysis,the wild Asian lotus samples in northern China were divided into three groups.The wild Asian lotus samples from northern China contained 16 haplotypes.The Nei’s genetic distance between the wild Asian lotus samples from the Songhua River basin and the Liao River basin in northeastern China was relatively small,and these germplasms might be relatively primitive compared to those from other regions.This study provides essential information regarding the genetic diversity of the wild Asian lotus resources in northern China,and provides a basis for further analysis of population-level genetic evolution through high-throughput sequencing.

Analysis of Accumulating Ability of Heavy Metals in Lotus (Nelumbo nucifera) Improved by Ion Implantation

Heavy metals have seriously contaminated soil and water, and done harm to public health. Academician WANG Naiyan proposed that ion-implantation technique should be exploited for environmental bioremediation by mutating and breeding plants or microbes. By implanting N^＋ into Taikonglian No.l, we have selected and bred two lotus cultivars, Jingguang No.1 and Jingguang No.2. The present study aims at analyzing the feasibility that irradiation can be used for remediation of soil and water from heavy metals. Compared with parent Taikonglian No.l, the uptaking and accumulating ability of heavy metals in two mutated cultivars was obviously improved. So ion implantation technique can indeed be used in bioremediation of heavy metals in soil and water, but it is hard to select and breed a cultivar which can remedy the soil and water from all the heavy metals.

Optimization of slow-release fertilizer application improves lotus rhizome quality by affecting the physicochemical properties of starch

To achieve the dual goals of high yield and good quality with low environmental costs,slow-release fertilizer(SRF)has been widely used in lotus cultivation as new type of fertilizer instead of traditional nitrogen fertilizer.However,the optimal amount of SRF and how it would promote lotus rhizome quality remain unclear.This study was designed to investigate the photosynthetic characteristics and the synthesis,accumulation,and physicochemical properties of lotus rhizome starches under six SRF levels(CK,S1,S2,S3,S4,and S5).Compared with CK(0 kg ha^(–1)),the net photosynthetic rate(P_(n))and SPAD values of leaves remained at higher levels under SRF treatment.Further research showed that SRF increased the lotus rhizome yield,the contents of amylose,amylopectin,and total starch,and the number of starch granules.Among the six SRF levels,S3(1035 kg ha^(–1))showed the greatest difference from CK and produced the highest levels.With the increasing SRF levels,the peak,hot and final viscosities decreased at first and then increased,but the setback viscosity and pasting temperature increased.In order to interpret these changes at the molecular level,the activities of key enzymes and relative expression levels of starch accumulation related genes were analyzed.Each of these parameters also increased under SRF treatment,especially under the S3 treatment.The results of this study show that SRF,especially S3(1035 kg ha^(–1)),is a suitable fertilizer option for lotus planting which can improve lotus rhizome quality by affecting starch accumulations related enzymes and genes.These results will be useful for SRF application to high-quality lotus rhizome production with low environmental costs.

白莲缘枯病病原菌的分离鉴定与防治药剂筛选

【目的】江西省白莲产区近年来莲缘枯病频发,对于莲子的产量和品质有着严重的负面影响。为明确莲缘枯病的病原种类,筛选出适用于防控该病害的化学药剂具有一定意义。【方法】通过形态学、分子生物学及柯赫氏法则对该病原菌进行鉴定,结合形态学与ITS、TEF1-α和β-tubulin进行序列分析,采用菌丝生长速率法,利用供试6种杀菌剂对病原菌进行室内毒力测定,筛选适用于防控该病害的化学药剂。【结果】引起白莲缘枯病的病原为小新壳梭孢菌(Nelumbo parvum),在6种供试药剂中,45%咪鲜胺、50%多菌灵可湿性粉剂和40%苯醚甲环唑悬浮剂的抑制效果最为明显,EC50分别为0.010、0.050和0.025μg/mL。【结论】45%咪鲜胺、50%多菌灵和40%苯醚甲环唑三种杀菌剂对小新壳梭孢菌的杀菌效果较好。

Whole genome re-sequencing reveals evolutionary patterns of sacred lotus (Nelumbo nucifera)

Sacred lotus(Nelumbo nucifera or lotus) is an important aquatic plant in horticulture and ecosystems. As a foundation for exploring genomic variation and evolution among different germplasms, we re-sequenced 19 individuals from three cultivated temperate lotus subgroups(rhizome,seed and flower lotus), one wild temperate lotus subgroup(wild lotus), one tropical lotus group(Thai lotus) and an outgroup(Nelumbo lutea). Through genetic diversity and polymorphism analysis by non-missing SNP sites widely distributed in the whole genome, we confirmed that wild and Thai lotus exhibited greater differentiation with a higher genomic diversity compared to cultivated lotus. Rhizome lotus had the lowest genomic diversity and a closer relationship to wild lotus, whereas the genomes of seed and flower lotus were admixed. Genes in energy metabolism process and plant immunity evolved rapidly in lotus, reflecting local adaptation.We established that candidate genes in genomic regions with significant differentiation associated with temperate and tropical lotus divergence always exhibited highly divergent expression pattern. Together, this study comprehensive and credible interpretates important patterns of genetic diversity and relationships, gene evolution, and genomic signature from ecotypic differentiation of sacred lotus.

湘莲根际促生菌的筛选及其效应研究

为获得湘莲根际促生菌(Plantgrowth promoting rhizobacteria,PGPR)并明确其促生特性,试验从湘莲根际土壤中分离出7株固氮解磷菌,通过对其功能指标的对比挑选出菌株XL7,其具有良好的固氮解磷和产IAA能力。经鉴定该菌株为高地芽孢杆菌(Bacillus altitudinis)。通过种子萌发、盆栽试验测定菌株对湘莲的促生效应。结果表明:接种XL7能促进种子的萌发,发芽势、发芽率、苗长、苗重和不定根重均高于对照;土壤中矿质态氮、速效磷和速效钾分别提高了5.3%、31.8%和26.1%;莲幼苗植株生物量、全氮、全磷和全钾分别增加了25.0%、18.3%、80.5%和38.7%。这表明该多功能菌株对湘莲具有良好的促生作用。

不同观赏荷花品种对镉胁迫响应的差异性研究

[目的]本文旨在探讨不同观赏荷花品种耐镉(Cd)的差异,筛选优质荷花品种以作为植物修复Cd污染水体的材料。[方法]以常用的6个大中型观赏荷花品种为试材,利用盆栽试验研究不同Cd处理水平(0、1、10、25 mg·kg-1)下各荷花品种生长及生理特性的变化。[结果]低Cd处理(1 mg·kg-1)促进了各荷花品种株高和立叶数的增加,中Cd处理(10 mg·kg-1)对‘风卷红旗’‘中国红·北京’‘珠峰翠影’的株高和立叶数有促进作用,但抑制其他3个品种的生长,经高Cd处理(25 mg·kg-1)后仅‘珠峰翠影’的株高和立叶数仍显著增加;不同Cd处理水平对各荷花品种冠幅和叶径的生长均产生了抑制效果。随着Cd处理水平升高,各荷花品种叶片的叶绿素含量逐渐降低,相对电导率不断上升,超氧化物歧化酶(SOD)和过氧化物酶(POD)活性均呈先上升后下降的趋势。其中,‘风卷红旗’‘中国红·北京’和‘珠峰翠影’叶绿素含量及相对电导率受Cd胁迫的影响较其他3个品种小,且‘风卷红旗’和‘中国红·北京’的2种抗氧化酶活性仅在高Cd胁迫下才显著低于对照,而‘珠峰翠影’在各水平Cd处理下始终高于对照。对不同荷花品种Cd积累特性的分析表明,‘风卷红旗’和‘中国红·北京’的Cd积累量相对较高,而‘珠峰翠影’的Cd转运系数最高;荷花不同器官中Cd积累量由大到小表现为根、叶、根状茎。[结论]不同观赏荷花品种耐Cd能力差异较大,‘珠峰翠影’‘风卷红旗’‘中国红·北京’的耐Cd性相对较强,这3个耐性品种可通过根系阻挡与固定大量Cd或高效启动抗氧化系统清除Cd诱导产生过量活性氧的方式抵御Cd胁迫。

典型状态下荷叶润湿性差异及其机理分析

为了研究荷叶不同状态下润湿性差异的成因与机理,通过对荷叶在鲜、老、病、枯4个典型状态下进行润湿性观察、与水接触角测量、扫描电镜观测,分析其表面微观形貌、化学蜡质含量等要素的变化规律,揭示润湿性差异的成因与机理。结果表明:鲜叶为微米级乳突和纳米级蜡质层覆盖的二元复合微观形貌,枯叶乳突和蜡质层稍有萎缩,但微观结构变化不显著;老叶微观形貌中出现了少许"板条"状突起和乳突、蜡质层共同构成其粗糙叶表结构;而病叶"乳突+蜡质层"的二元复合结构发生明显变化,呈现无序的线型纤维柱状网络结构。不同状态荷叶表面与水接触角测量结果显示,鲜、老、枯叶仍呈现疏水或超疏水状态,而病叶呈现亲水状态,润湿性能发生根本改变。荷叶表面蜡质含量在不同状态下也存在一定差异,老叶、枯叶蜡质含量与鲜叶接近,但疏水性皆低于鲜叶。研究表明荷叶不同状态下润湿性差异的成因在于其叶表微观形貌和化学蜡质含量发生改变造成的,从这2个因素对其疏水性的贡献率来比较,叶表微观形貌是决定其疏水程度的主因。研究结果为疏水表面仿生设计提供参考。

莲藕膨大过程中碳水化合物变化的初步研究

在莲藕膨大过程中,测定其干物质、淀粉、可溶性总糖、还原糖、可溶性蛋白质等含量,研究碳水化合物的变化规律。结果表明:干物质、淀粉和可溶性蛋白质含量在莲藕膨大过程中均逐渐上升,至膨大后期有一个急增过程;还原糖含量先有所上升,膨大中期迅速下降,至膨大后期维持较稳定水平;可溶性总糖含量从膨大始期至膨大中期平缓上升,至膨大后期则迅速增加。莲藕根状茎的储藏物质主要为淀粉。

钾营养对莲藕产量形成和氮磷钾养分累积分配的影响

【目的】研究钾营养对莲藕产量形成及氮磷钾养分积累与分配的影响。【方法】采用盆栽试验,设置不施钾(-K)和施钾(+K)处理进行全生育期试验。【结果】莲藕移栽76d后,+K处理叶片和叶柄干物质累积量明显高于-K处理,并均在97d膨大茎成型后逐渐降低;膨大茎干物质累积速率和累积量在早期为+K处理低于-K处理,97d后+K处理的干物质累积速率明显加快,其累积量于139d明显高于-K处理,160d不同处理膨大茎干物质累积量趋于稳定,+K处理为1204g/株,比-K处理高19.7%。在97—160d产量形成关键期,膨大茎中氮、磷和钾的累积量,+K处理比-K处理分别高32.8%、10.3%和74.2%,其中来自其它器官转移的氮、磷和钾,+K处理比-K处理分别高1.20、0.12和1.26g/株,来自根系直接从土壤中吸收转运的氮、磷和钾,前者比后者高2.16、0.04和5.70g/株。莲藕氮、磷、钾累积总量之比-K处理为1﹕0.14﹕0.90,+K处理为1﹕0.13﹕1.31。【结论】钾营养促进莲藕干物质生产和累积、促进根系对养分的吸收并提高莲藕各器官尤其是叶柄中钾的含量,在生育后期促进干物质和养分从叶片等器官转移并贮存到膨大茎中并最终增产。

钾素营养对莲藕生长和干物质累积的影响

采用大盆试验研究了钾素营养对莲藕生长和干物质累积的影响,结果表明,钾素营养明显增加莲藕立叶数量和立叶面积、提高立叶相对叶绿素值和组织器官含水量、延缓叶片衰老、增强立叶抗逆性,从而促进莲藕生育前期光合产物的累积和健康生长;钾素营养还适当延长莲藕成熟期,促进干物质从叶片转移并贮存到产品中,使莲藕增产20.4%。

莲子蛋白的组成、溶性和品质

广昌干白莲莲子中含蛋白质量分数为24．94％，比其他30个品种的平均值高15％，其氨基酸组成中必需氨基酸的比例符合世界卫生组织规定要求，盐溶球蛋白和水溶清蛋白占总蛋白含量的76.23％，醇溶蛋白仅占0.33％．主要蛋白亚基有8个，相对分子质量在98×103～16×103之间．讨论了莲子贮存蛋白基因作为优秀蛋白基因材料的应用前景，还就其种子蛋白的贮存部位、含量、溶性及必需氨基酸的比例论证了莲归属双子叶植物的合理性．

野生莲资源的RAPD分析

利用16个随机引物对来自6省的12份野生莲(Nelumbonucifera)资源材料进行了RAPD分析。扩增形成141条谱带,其中多态带79条,占56.03%。显示野生莲在我国具有丰富的遗传多样性。结果还表明:1)野生莲资源遗传分化十分明显,虽有一定的地域相似性,但有些地区的分化也很明显;2)野生莲资源可分为3类,与园艺学分类比较相似,可能暗示了现代莲由不同遗传背景的野生莲演化而来。

湖北省莲藕品种演变及栽培利用特点

湖北省是莲藕起源地之一,亦为我国莲藕重要产区。其品种演变历史可划分为传统品种阶段(1980年以前)、新品种选育的起步和奠基阶段(1980～1990年)、传统品种更新和新品种快速推广与持续选育时期(1990年以后)。不仅拥有许多传统品种,而且选育了多个新品种,是我国莲藕新品种的主要选育地区。在莲藕茬口配置、设施栽培、种藕繁殖、采挖以及莲藕产品开发利用等方面具有明显的地方特色。

莲多酚氧化酶基因的克隆及序列分析

多酚氧化酶是一类普遍存在于植物、真菌、昆虫的质体中,由核基因编码能与铜相结合的金属蛋白酶。它是许多果蔬等农产品酶促褐变的主因,也在植物的光合作用、抗病虫害、生长发育以及花色的形成中起一定作用。用RT-PCR方法,从中国莲(Nelumbonucifera)幼叶RNA中成功扩增出ppo的部分序列,经克隆测序,得到长度在978～1057bp的序列共7个,编码326～352个氨基酸。与其他物种PPO进行比较,其核苷酸序列相似性为83%～85%,氨基酸序列相似性为84%～99%。莲ppo的成功克隆为抑制莲藕的酶促褐变,提高莲的抗虫抗病性等的研究打下了良好的基础。

莲房原花青素对氧自由基和脂质过氧化的作用

目的 : 观察莲房原花青素 ( LSPC)对活性氧自由基 O·-2 、· OH和肝脂质过氧化损伤的作用。方法 : ( 1 )应用化学发光法检测 LSPC对 O·-2 和· OH的清除作用 ;( 2 )体外大鼠红细胞、肝线粒体温育引起肝脂质过氧化物 ( LPO)含量变化 ;( 3)体外大鼠肝匀浆温育 ,Fe2 +、H2 O2 诱导引起 LPO含量变化 ;( 4 )小鼠连续口服不同剂量 LSPC 7d后 ,一次性灌胃 5 % CCl4油溶液 1 0 ml/kg bw,2 4 h后检测肝和血浆中超氧化物歧化酶 ( SOD)活性、谷胱甘肽 S-转移酶 ( GST)活性以及脂质过氧化物 ( LPO)含量。结果 : LSPC能有效地清除活性氧自由基 O·-2 和· OH,其 IC50 值分别为 1 69.0 mg/L和 1 0 5 .3mg/L;不同剂量 LSPC能明显抑制体外大鼠红细胞、肝线粒体、肝组织LPO产生 ;口服中、低剂量 LSPC能显著降低 CCl4中毒小鼠体内 LPO含量 ,提高 SOD、GST活性。结论 : 适量 LSPC具有抗活性氧自由基和脂质过氧化的作用 ,可能具有护肝功能。

莲膨胀素基因的克隆及其序列分析

膨胀素是一类存在于植物细胞壁上,并能快速缓冲张力,使植物细胞壁松驰的蛋白质。以中国莲幼叶总RNA反转录所得的cDNA为模板,设计简并引物,用PCR方法成功扩增出expansin部分序列,经克隆测序,得到长度在531￣532bp的序列共3个,编码177个氨基酸,而且均存在expansin的保守区域。与其它物种,如杂交杨树、烟草、杂交葡萄、野马铃薯、樱桃等物种的expansin相比,核苷酸相似性为84%￣85%,氨基酸序列相似性为86%￣99%。莲expansin的成功克隆为研究莲的生长发育以及莲品种的改良等打下了良好的基础。

莲藕克隆构型与环境的关系

对莲〔NelumbonuciferaGaertn〕在水田及鱼塘的克隆生长格局进行了研究,调查了三个或三个以上的品种莲的叶片大小、叶柄高度、节间长度、分枝角度、分枝节位、结藕节位等参数。结果表明,莲根茎分枝类型为单轴型,新生的次生根茎交替着水平伸向上级根茎的两侧,分枝角度62.6～98.7°,品种之间存在差异。不同品种莲叶柄高度、叶柄粗度、根状茎节间长度、根状茎节间粗度随着植株生长越来越大,与以前报道并不一致。主枝结藕节位可作为判断莲藕熟性的指标之一。莲克隆构型在不同品种、不同生长环境之间有明显差异。

僵藕的发生与矿质营养关系的研究

分析了僵藕发生与矿质营养的关系。结果表明 :①僵藕田土壤中有机质和有效性矿质离子含量均略低于正常田 ,但差异不显著 ;②在肥沃土壤中生长的僵藕叶中矿质元素含量一般均低于正常藕 ,根状茎中 ,锰、铜、铁、锌的含量极显著高于正常藕 ,钙显著低于正常藕 ;③僵藕栽培在营养液中 ,其子藕仍为僵藕 ,在矿质营养缺乏条件下的正常藕不发生僵化。因此 ,僵藕并非因矿质营养缺乏直接所致。