油菜×蔊菜远缘杂交创新油菜种质资源研究

本项研究重点是要探讨通过油菜与蔊菜远缘杂交,将蔊菜的某些优良性状转移到栽培油菜中的可行性.结果表明甘蓝型油菜与蔊菜进行远缘杂交有较好的亲和性.而且其杂交后代变异明显,出现了许多碎叶型植株和一些类似白菜型的植株,杂交后代对菌核病有较强的抗性,有许多具有优势的单株.油菜与蔊菜进行远缘杂交对于创新油菜种质资源,培育高产、高抗油菜新品种具有重要意义.     

不同环境对蔊菜群体变异式样的影响

蔊菜(Rorippa indica(L.)Hiern))和无瓣蔊菜(R.dubia(Pers.Hara)是两个形态相似的近缘种,还是同一种植物的不同变异式样,分类学家历来有不同看法。本文通过不同生境的7个自然群体取样和2个人工控制的栽培群体栽种,以群体为单位,分别测算花蕾中花瓣数和果实内种子列数;对具代表性不同生境的群体取花粉粒进行电镜扫描。结论是:蔊菜和无瓣蔊菜可能是同一种植物的不同变异式样,作为同一种植物来对待也许是合适的。     

蔊菜杂草性的研究

本文通过对十字花科常见杂草芹菜[Rorippa in lica(L.)Hiern]在南京地区的自然群体的周期性观察,以了解其在不同生态环境下的生活周期。本文还通过一系列实验来观察其繁育系统、种子传播的动因、结实力、种子发芽率和植物抗人为干扰的耐受性。花蕾套袋试验证明蔊菜主要是自交可亲和的,即使存在异型杂交也是微不足道的。种子传播效应试验揭示水和风都是种子传播的自然力。该种具有范围很广的耐受性,踏践和刈割试验证明在严重的人为于扰下仍能完成其生活周期。蔊菜尽管本质上属于多年生草本,能产生大量的种子,在很大程度上靠种子繁殖。种子萌芽试验证明它的种子萌发参差不齐。总之,蔊菜具有典型杂草的许多特性,而这些特性给它以适合在多种自然的和人为干扰的环境中正常地生长的能力。     

蔊菜幼苗抗菌核病及抗旱和耐湿特性的鉴定

以3个甘蓝型油菜(Brassica napus L.)品种‘中油821’(‘Zhongyou No.821’)、‘中双9号’(‘ZhongshuangNo.9’)及‘中油杂2号’(‘Zhongyouza No.2’)为对照,采用离体叶片菌丝块接种法、人工模拟干旱和湿害胁迫处理法对蔊菜〔Rorippa indica(L.)Hiern〕的抗菌核病〔Sclerotinia sclerotiorum(Lib.)de Bary〕、抗旱和耐湿特性进行了鉴定。结果表明:菌核病菌接种后,蔊菜幼苗叶片的病斑直径为1.75 cm,极显著小于3个甘蓝型油菜品种的病斑直径(3.25～3.60 cm)。经干旱胁迫后,3个油菜品种的幼苗严重萎蔫,茎粗、根长以及地上部分、根和全株的鲜质量和干质量均极显著低于对照;蔊菜幼苗轻度萎蔫,仅茎粗和根鲜质量分别极显著和显著低于对照,其他生长指标与对照差异不显著;蔊菜幼苗各生长指标的伤害指数均显著或极显著低于3个油菜品种。经湿害胁迫后,蔊菜和3个油菜品种幼苗的总叶片数和绿叶数较对照明显减少、黄叶数增加,但蔊菜幼苗的黄叶数显著少于3个油菜品种;3个油菜品种幼苗的茎粗、根长以及地上部分、根和全株的鲜质量和干质量总体上显著或极显著低于对照,而蔊菜幼苗仅茎粗、根长和根干质量显著低于对照,其他生长指标与对照差异不显著;蔊菜幼苗的茎粗,根长,地上部分、根和全株的鲜质量以及根和全株的干质量的伤害指数均显著或极显著低于3个油菜品种。研究结果显示:蔊菜对菌核病的抗性及抗旱和耐湿性均强于供试的3个甘蓝型油菜品种,是十字花科(Brassiaceae)中对菌核病抗性强、抗旱耐湿的优质基因源。     

印度蔊菜与无瓣蔊菜形态变异特征的比较及分类关系

印度蔊菜(Rorippa indica)与无瓣蔊菜(R. dubia)的分类关系仍存在较大争议, 为阐明二者的分类学关系, 本研究综合利用形态指标测量、DNA相对含量检测、体细胞染色体观察和基于SSR分子标记的遗传距离分析等方法, 系统地比较了二者的分类学特征和细胞遗传学差异。结果表明: 印度蔊菜(2n = 48)为六倍体, 无瓣蔊菜(2n = 32)为四倍体。同时, 前者DNA相对含量约为150, 是后者的1.5倍。通过45对SSR分子标记的遗传距离分析得出, 相对于球果蔊菜(R. globosa)与欧亚蔊菜(R. sylvestris), 二者亲缘关系较近, 独立聚类为一支, 但在遗传距离为0.23处可以明确划分为两个种。同时, 利用角果长度和结籽密度两个形态指标可以将二者明显区分为两个种。另外, 二者存在明显的生殖障碍, 通过正反交授粉实验得出: 印度蔊菜与无瓣蔊菜自花授粉的结实率分别为97.73%和95.65%, 而以印度蔊菜为母本的杂交处理结实率为0, 以无瓣蔊菜为母本的杂交处理结实率为47.06%, 但其种子萌发率为0。综上所述, 印度蔊菜与无瓣蔊菜为两个种。     

中国白粉菌属的分类研究Ⅳ.十字花科上的一个新种

本文描述了采自北京香山的细子薄菜 Rorippa cantoniensis(Lour.)Ohwi(十字花科)上的一种新白粉菌 Erysiphe rorippae Chen & Zheng sp.DOV.蔊菜属是白粉菌属的寄主新记录。在附属丝形态上,本新种因附属丝往往在顶部略膨大呈棍棒形而与唇形科上的华阴白粉菌 Erysiphe huayinensis Zheng & Chen 颇为近似,但因子囊壳直径较大,子囊孢子数目较少、体积较大且在两端钝尖而与该种很易区分。与十字花科上的另外两个已知种,即十字花科白粉菌 Erysiphe cruciferarura(Opiz)Junell 和南芥白粉菌 Erysiphe arabidisZheng & Chen 相比则无论在什么方面都没有共同之处。这三个种可检索如下:     

甘蓝型油菜与蔊菜的原生质体融合与植株再生

以甘蓝型油菜下胚轴和蔊菜叶片为外植体提取原生质体, 采用PEG-高pH、高Ca²⁺附加DMSO的原生质体融合方法, 用液体浅层静置培养融合体, 获得了10株融合杂种, 观察了杂种形态学和细胞学。结果表明：1%纤维素酶+0.2%离析酶+3 mmol/L MES 酶解14 h 可获得较高产率的油菜原生质体, 0.25% 纤维素酶+0.5%离析酶+5 mmol/L MES酶解12 h可获得较高产率的蔊菜原生质体; 30% PEG + 0.3 mol/L葡萄糖+50 mmol/L CaCl₂•2H₂O +15%DMSO的融合条件下, 获得了10.4%的融合率; 实验所获的原生质体融合材料可作为新种质。     

甘蓝型油菜与蔊菜属间杂种后代的苗期耐湿性综合评价

以生产上应用的耐湿性存在差异的3个甘蓝型油菜品种为对照,采用盆栽模拟湿害胁迫的方法,对15份源自甘蓝型油菜与蔊菜属间杂交获得的遗传稳定的创新种质进行苗期耐湿性鉴定和综合评价。结果显示:(1)湿害抑制根系生长,导致植株变矮,叶片发黄,生物量降低,湿害对根系影响最为严重,其次是植株总生物量积累和地上部分的生长。(2)通过主成分分析和隶属函数法,将全展叶数、绿叶率、苗高、根长、地上部分鲜重、根鲜重、植株总鲜重、地上部分干重、根干重和植株总干重等10个性状指标值转化成单一的综合评价值(D值),客观、科学、准确地对参试的18份材料进行了综合评价,为甘蓝型油菜苗期耐湿性评价提供了方法参考。(3)15份创新种质除绿叶率外的9个测定指标的耐湿性系数均高于对照品种,耐湿性综合评价结果显示,15份创新种质的D值均高于渝黄2号,13份创新种质的D值高于综合抗耐性俱佳的中油821,3份创新种质的D值高于高耐湿品种中双9号,聚类得到的高耐湿类群的7份材料中创新种质占6份(85.71%)。可见,创新种质的耐湿性平均要优于对照品种,说明通过远缘杂交获得的创新种质对甘蓝型油菜的耐湿性有了较为明显的改良和提高。     

蔊菜和珍珠露水草的组织培养

植物名称:蔊菜(Rorippa montana)珍珠露水草(Cyanotis arachnoidea)。材料类别:蔊菜茎段及珍珠露水草叶鞘。培养条件:基本培养基为MS。诱导愈伤组织和芽的培养基附加(1)NAA1mg/l(下同),2,4-D0.1,BA0.5;(2)NAA0.2,BA2;(3)NAA0.05,BA1。诱导生根培养基为1/2MS附加NAA0.1。培养温度25—28℃,每天光照12小时,光照度1500—2000lx。生长与分化情况:蔊菜茎经消毒后切成长约0.5cm的茎段,接种到培养基(1)上进行暗培养。外植体产生明显的肿胀状愈伤组织,并发生开裂,     

不同纬度高蔊菜的交配系统和繁殖保障

高山植物的繁殖适应策略一直是进化生态学研究的热点, 但是目前仍缺乏对繁殖适应性状的量化研究。本研究以横断山特有十字花科植物高蔊菜(Rorippa elata)为研究材料, 结合野外同质园控制实验, 在居群水平探讨了其繁殖适应策略。结果表明, 高蔊菜的繁殖能力与纬度呈负相关, 而越冬存活率与纬度呈正相关。不同交配方式结实率的显著性差异分析表明, 高蔊菜具有混合交配系统, 其中自交为主型和中间型的株系各占45.5%和39.4%; 不同株系具有不同程度的繁殖保障现象, 自交为主型最高(0.163), 中间型最低(0.011)。本研究表明高蔊菜在居群水平的繁殖和存活之间存在沿纬度梯度的权衡变化, 以自交为主的混合交配系统为其提供不同程度的繁殖保障。     

风花菜根异常次生结构的解剖学观察

利用光镜观察了风花菜（Rorippa islandica (Oed.)Borb.）的根的发育过程中的解剖结构的变化,发现风花菜根具有异常次生结构,第一年早期次生结构中,在导管周围形成额外形成层并由额外形成层向内外分裂形成大量的薄壁组织,从而使根快速增粗,在根的横切面上,导管分散在薄壁组织当中。第一年晚期的次生结构中,由木质部中薄壁组织细胞反分化形成额外形成层,许多分散的额外形成层片段连接形成形成层环,形成层环向内向外分裂形成三生木质部及三生韧皮部,从而构成三生维管组织环,三生维管组织环形成方向由外向内,可以形成多环。第二年风花菜的韧皮部以及皮层中的薄壁组织反分化形成额外形成层,并且由额外形成层片段连接形成额外形成层环,进而分裂形成三生维管组织环,而且在皮层中可以形成多层,形成的方向为由内向外。风花菜根不同发育时期的异常次生结构是与其生理活动相适应的。     

Chloroplast DNA Variation and Biogeography in the Genus Rorippa Scop. (Brassicaceae)

Abstract: Phylogenetic relationships and biogeography of 25 Rorippa species were studied using sequences of two non-coding regions of chloroplast DNA ( trn L intron, trnL /F spacer). Our results indicate a close relationship between European ( R. islandica ssp. islandica, R. pyrenaica ) and North American (R. curvipes, R. sinuata) mountain species. The polyploid European lowland species R. amphibia, R. palustris and R. sylvestris are much younger than the mountain species and have their closest relatives in western Asia and Siberia. Different colonization routes of the southern hemisphere are discussed for Rorippa. Australasia was colonized at least twice, most likely via the Malayan route. A molecular clock approach dates the first colonization to the end of Pliocene or early Pleistocene. R. gigantea reached Australia later in the Pleistocene. Our data provide evidence for an amphitropical disjunction between the South American (R. philippiana) and North American (R. curvisiliqua) species. Long-distance dispersal via migrating birds is the most likely explanation for this intercontinental disjunction. Two of the analysed African species (R. nudiuscula, R. madagascariensis) have their closest relative (R. austriaca) in eastern Europe and western Asia. The lack of sequence divergence among these species indicates a colonization event probably not earlier than 100 000 years ago.     

Different flooding responses in Rorippa amphibia and Rorippa sylvestris, and their modes of expression in F1 hybrids

The river floodplain species Rorippa amphibia, Rorippa sylvestris, and their hybrid Rorippa x anceps were studied here, with the aim of identifying potential species differences with respect to flooding tolerance, and of assessing their expression in F1 hybrids. Parents and their F1 hybrids were subjected to three flooding treatments mimicking natural conditions, and growth-related and leaf morphological traits were compared. In contrast to R. sylvestris, R. amphibia responded to waterlogging by forming specialized roots, and its growth was not reduced. These traits were dominantly expressed in hybrids. Both species and the hybrids established shoot growth over 2 wk of complete submergence. Only in R. sylvestris was this not at the expense of root biomass, suggesting that R. sylvestris can photosynthesize underwater. Rorippa sylvestris also showed a hyponastic response. Hybrids were intermediate to the parents in this respect. This study shows that phenotypic expression of parental traits in F1 hybrids is mostly additive, but can also be dominant. This suggests that a large overlap in habitat use of parents and hybrids is likely. If such an overlap occurs, the main evolutionary consequences of hybridization in Rorippa will be the introgression of genes, as the hybrids are fully fertile.     

Development of highly conserved primers for 12 new polymorphic microsatellite loci for the genus Rorippa Scop. (Brassicaceae), yellow‐cress

We isolated 12 highly conserved polymorphic microsatellite loci for the yellow‐cress species Rorippa amphibia and Rorippa sylvestris. We used a partial genomic library enriched for several repeat motifs. Obtained sequences containing repetitive elements were blasted and aligned with the Arabidopsis thaliana sequence. We evaluated the cross‐species compatibility of primers designed from sequences either aligning strongly or weakly with A. thaliana. The former proved much more efficient in obtaining primers that worked in both species. The developed conserved primers for microsatellite loci provide excellent markers for studying segregation, gene flow and hybridization in the genus Rorippa.     

Reconstructing the spread of invasive plants: taking into account biases associated with herbarium specimens

Aim To reconstruct the spread of invasive wetland species using herbarium specimens and to develop a method that accounts for the biases associated with this type of historical record. Location Southern Québec. Methods The temporal and spatial distribution of herbarium specimens of vascular plants was examined. Six invasive species that are mainly found in wetlands were compared with five native, non‐expanding hydrophytes. The cumulative number of locations was plotted against time to construct invasion curves. For native species, this ‘invasion curve’ indicates the spatiotemporal distribution of the sampling for herbarium specimens of wetland plants. It also represents the history of the state of knowledge of the distribution of native species. Deviation from the native species invasion curve can be used to describe the spread of invasive species. For every year on record, the cumulative number of locations of each exotic species was divided by the cumulative number of locations of all native species, and the proportions obtained were plotted against time. Periods of invasiveness were then delineated. Results During the twentieth century, two periods of intensive herbarium specimen collection in Québec can be clearly distinguished, i.e. from 1930 to 1940 and from 1950 to 1985. Several periods of invasiveness were delineated for Butomus umbellatus L. (1922–35), Hydrocharis morsus‐ranae L. (1957–96), Lycopus europaeus L. (1963–2000), Lythrum salicaria L. (1890–1905, 1923–46), Phragmites australis (Cav.) Trin. ex Steudel (1963–84) and Rorippa amphibia (L.) Bess. (1929–34, 1943–52, 1971–79). Main conclusions Accounting for sampling biases associated with herbarium specimens is important in order to objectively delineate periods of invasiveness for exotic species. The spread of wetland vascular plant species can be reconstructed using herbarium specimens, even when the phenomenon is rapid, but the reconstruction is certainly more accurate when the invasion occurred during an active sampling period. The highly variable sampling effort for herbarium specimens in Québec and in other regions strongly cautions against using herbarium data without correction procedures.     

The plastic reproductive allocation of the cruciferous perennialRorippa indica in response to different degrees of feeding damage

The degree of feeding damage in the wild to the cruciferous perennial Rorippa indica (L.) Hieron ranged from 0% (not damaged) to 100% (heavily damaged). However, “not damaged” and “heavily damaged” individuals did not differ in the relative suitability of their intrinsic traits for P. rapae, which caused the heaviest damage on the plant. Therefore, the different degrees of feeding damage may be due to variability in the extrinsic traits of the plant, that is, it may be determined by the habitat conditions where individual plants exist. Furthermore, R. indica allocated more resource to seed production at the expense of the roots when it was experimentally subjected to heavy leaf damage. The result suggested that R. indica individuals may escape, by means of seed dispersal and seed dormancy, from unfavorable habitats where they are heavily damaged by herbivores.