准噶尔无叶豆的引种栽培

准噶尔无叶豆的引种栽培刘生龙王理德高志海仲述军（甘肃省治沙研究所,武威７３３０００）ＴｈｅｉｎｔｒｏｄｕｃｔｉｏｎｅｘｐｅｒｉｍｅｎｔｏｆＥｒｅｍｏｓｐａｒｔｏｎｓｏｎｇｏｒｉｃｕｍ（Ｌｉｔｖ．）ＶａｓｓＬｉｕＳｈｅｎｇ－Ｌｏｎｇ,ＷａｎｇＬｉ－Ｄｅ...     

根茎型木本克隆植物准噶尔无叶豆的种群数量动态

 根据根茎型木本克隆植物的特征, 不以种群的分株数量代表种群大小, 而尝试以不同茎级的根茎长度代表种群大小, 运用种群静态生命表、存活曲线、生殖力表和Leslie矩阵模型, 研究了准噶尔无叶豆(Eremosparton songoricum)的两个种群——A种群(46°31.09′ N, 88°33.06′ E, 紧邻乌伦古湖)和B种群(46°28.07′ N, 88°33.07′ E, 位于沙漠腹地)的种群数量动态。结果表明: 种群存活表现为Deevey-I型。A种群在中龄阶段受到的人为干扰较大, 死亡率出现高峰, 种群的净增长率(R₀)、内禀增长率(r_m)和周限增长率(λ)较低, 表现为衰退型种群, Leslie矩阵模型的模拟结果表明, 15 a内种群呈现下降趋势; B种群所受到的压力主要是干旱贫瘠的荒漠环境所导致的系统压力, 种群的R₀、r_m和λ值适中, 表现为缓慢增长型种群, Leslie矩阵模型的模拟结果表明, 15 a内种群呈现先下降、再上升的趋势。此外, 研究结果验证了Leslie矩阵模型可以扩展应用到根茎型木本克隆植物这类特殊生活型植物的种群数量动态研究上。     

准噶尔荒漠大翅霸王的生殖物候及结实格局

大翅霸王是多年生早春开花草本植物,是准噶尔荒漠地区的建群种之一。对野生大翅霸王的生殖物候、果实形态、结实格局和种子萌发特性进行了研究。结果表明:(1)大翅霸王的营养期生长期为20—30d,占整个生活周期的1/4,生殖生长期长约90—100d,其中花期约占1/2,果熟期短;(2)大翅霸王种群能产生3种形态的果实,可将植株分为5翅型、4/5翅型和3/4/5翅型植株,它们分别占种群植株数的3.45%、83.15%和13.40%。(3)依据个体大小的变化,3种类型果实在植株上的比例发生了显著变化。随植株个体的增大,三翅果所占比例逐渐增多,由0增加到2.65%;四翅果所占比例也增多,但在二级个体上有最大比例17.01%;五翅果实所占比例最高(80%)且没有显著变化。(4)三翅果、四翅果和五翅果内种子形态无差异,萌发率均小于30%;划破种皮能不同程度的加速和促进种子的萌发。大翅霸王特有的生殖物候和果实的表型多样性是其对荒漠干旱地区恶劣多变环境长期适应的结果。     

人工固沙区与流沙区准噶尔无叶豆种群数量特征与空间格局对比研究

准噶尔无叶豆(Eremosparton songoricum) 是中亚荒漠特有小半灌木,稀有种,在我国仅片段化分布于新疆古尔班通古特沙漠;它是流动沙丘的先锋物种,也能成功定居于人工固沙区(草方格)。对比研究了人工固沙区及自然流沙区的准噶尔无叶豆群落物种组成、种群密度、高度、盖度、生物量等特征及种群空间分布格局。结果表明:人工固沙区内的准噶尔无叶豆群落物种的科、属、种数均明显多于流沙区,而且2种生境物种相似性指数仅为0.522,表明人工固沙生境显著改变了群落物种组成与结构。除植株密度外,人工固沙区种群的高度,盖度,地上、地下及总生物量密度,单株地上、地下及总生物量等数量特征均显著高于流沙区。2种生境中准噶尔无叶豆种群空间分布的关联维数均接近2.0,体现了较强的个体空间相关性和空间占据能力。2种尺度(1 m和2 m)下的聚集度分析表明,2种生境中种群基本为随机分布。因而,人工固沙生境并未明显改变种群空间分布格局,这可能是种群的固有特性。人工固沙区的土壤有机质、全氮和有效氮含量显著高于流沙区,且与种群数量特征(植株密度除外)呈显著正相关。总之,与流沙区相比,人工固沙使地表得到固定,提高了土壤有机质和氮素含量,明显改变了定居于其中的准噶尔无叶豆种群主要数量特征,增强了种群的生存和适应能力。该结论对荒漠濒危植物的保育具有重要指示意义。     

准噶尔无叶豆的开花物候与生殖特征

 为了研究沙漠稀有植物准噶尔无叶豆(Eremosparton songoricum)的开花物候特征及其对生殖成功的影响, 2005和2006年连续两年对其自然种群的开花物候和开花过程中的花部表型变化进行了观察, 并运用相对开花振幅、开花强度和开花同步性等开花物候指数研究了开花物候特征。结果表明: 准噶尔无叶豆在5月下旬至6月中下旬开花, 其种群、个体、花序和单花的花期分别历时26~29 d、8~10 d、5~7 d和2~3 d。单花开花进程依其形态和散粉特征可分为散粉前期、散粉初期、散粉盛期和凋谢期4个时期。其个体水平的开花物候进程(开花振幅曲线)呈渐进式单峰曲线, 具有很高的开花同步指数, 表现出一种集中开花的模式。开花物候指数与座果数之间的相关分析结果表明, 始花日期与花期持续时间存在负相关关系, 而与开花数和座果数存在正相关关系; 花期持续时间与开花数和座果数存在显著正相关关系。准噶尔无叶豆个体开花物候在很大程度上是由其遗传因子决定的, 而开花物候在年度间的变异, 可能是由于荒漠气候的差异(主要是水分和温度的差异)所引起的。作为沙漠窄域分布特有种, 准噶尔无叶豆在环境和人为干扰的双重选择压力下, 为了吸引更多的传粉者访问而达到生殖成功, 形成了大量集中开花的模式。     

沙丘坡面异质性小生境中准噶尔无叶豆对水分条件变化的响应

以多年生克隆植物准噶尔无叶豆(Eremosparton songoricum(Litv.)Vass.)为材料,选择河边(A种群)和沙漠腹地(B种群)两个沙丘,研究从沙丘底部至顶部,沿着水分条件连续变化的梯度,准噶尔无叶豆在分株种群和克隆片段水平的形态变化特征,以期能揭示其在异质性小生境内利用水分资源的对策,并为准噶尔无叶豆的资源保护、培育和利用提供有意义的参考.研究发现:①在分株种群水平,A种群分株高度及地上部生物量显著高于B种群,而B种群地下部(根)的生物量则显著高于A种群;②在克隆片段水平,随着沙丘底部至顶部,A种群与B种群克隆片段高度和地上生物量都减小,而分株密度都增加,但升高或降低的强度不同;A种群根的生物量和长度增加,主要是水平的位于地下0～10 cm层面的直径10mm以下的根长度增加,而B种群根的生物量减小,但长度却在增加,主要是水平的位于地下0～10 cm层面的直径6mm以下的细根长度增加.水平细根的长度增加,更利于无性系进行广泛觅食,同时促进无性系尽快越过不利生境斑块和提高分株在有利生境中的生长概率.结果表明,准噶尔无叶豆对沙丘坡面水分条件连续变化的异质性小生境存在分株种群及克隆片段两个等级的可塑性响应,并通过可塑性变化适应了沙丘坡面水分条件的分异.     

大花百子莲的结实和结籽格局及种子产量影响因素分析

在2007和2008年对大花百子莲(Agapanthus praecox subsp.orientalis‘Big Blue’)在群体、果序和单果水平上的结实和结籽格局进行了观测,并依据每花序单花数、单花胚珠数和单粒种子质量推算其单株潜在种子产量;此外,采用人工补充授粉方法研究了不同授粉方式对大花百子莲结实和结籽的影响,并对其种子产量的影响因素进行了分析。结果表明:从始花期、盛花期至末花期,随开花时间的延迟,大花百子莲植株的每花序单花数和座果率均逐渐降低,其中始花期开花的植株每花序单花数和座果率均最高。从果序基部、中部至顶端,座果率和结籽率均逐渐减小且差异显著。在果序基部和中部,果实内种子败育率沿果实基部至顶端依次降低,而单粒种子质量则依次增加;且果序基部的果实各部位的种子败育率均低于果序中部的果实,而单粒种子质量则差异不大。大花百子莲的单株潜在种子产量约为43.18 g,而其单株实际种子产量约为2.87 g,远低于其潜在种子产量。自然授粉的大花百子莲每柱头花粉数为27.5粒,而自花授粉、同株异花授粉和异株授粉的每柱头花粉数均超过100粒;与自然授粉、自花授粉和同株异花授粉植株相比,异株授粉植株的座果率和结籽率均显著增加。研究结果显示:大花百子莲的结实和结籽格局呈现非随机分布规律,在引种地存在有性繁殖障碍;养分和授粉状况是制约大花百子莲种子产量的重要因素。     

不同水分下准噶尔无叶豆分株种群特征和生物量分配差异

准噶尔无叶豆是豆科无叶豆属小半灌木,在中国仅片断化分布于新疆古尔班通古特沙漠局部区域.该种自然种群种子萌发率极低(<3%),主要靠克隆繁殖维持种群.为研究克隆生长在异质性生境中的可塑性特征及其生态适应意义,对生境土壤含水量存在差异的两个准噶尔无叶豆自然种群(河边种群,沙漠种群)的分株种群特征、生物量及其分配比重进行了比较,研究发现:①在分株种群特征上,河边种群的分株显著高于沙漠种群,分株间距也显著大于沙漠种群.沙漠种群分株密度和根的密度显著大于河边种群,但每一分株拥有根的概率显著小于河边种群;②在生物量分配方面,河边种群具有比沙漠种群大的根生物量,但根茎生物量则要显著的小于沙漠种群;③在植株各部分生物量比重随植株大小的变化趋势上,河边种群各部分的比重随植株大小变化的趋势平缓,而沙漠种群各部分的比重变化趋势则较为急剧,表明河边准噶尔无叶豆分株种群随着植株的大小变化,资源分配比例并没有发生很明显的变化,而沙漠种群变化较大.结果表明,准噶尔无叶豆种群对所处生境水分条件存在可塑性响应,并通过分株种群特征变化和生物量分配差异应对水分条件的变化,形成自身的适应对策.     

种子植物的选择性败育及其进化生态意义

种子植物的选择性败育是指植株在花粉源、传粉次序、果实在植株上的位置和发育果实中的种子数目等因素或者这些因素综合作用的基础上对发育中的幼果或种子选择性败育的现象。植株可以选择性地败育位于果序顶部或基部的果实以及位于果实基部、中部或柱头端的种子。此现象在被子植物中比较普遍,特别是在豆科、十字花科和紫草科中最为常见。导致植物选择性败育的主要原因主要有资源限制和遗传因子两个方面。植物通过选择性败育部分自交或基因型较差的果实或种子,不仅可以提高母本和后代的适合度,而且还可以提高果实或种子的扩散效率。因此,对选择性败育的研究在深入了解植物的结实结籽格局、探讨其进化式样与机制等方面具有重要意义。该文系统总结了国际上有关植物选择性败育的研究工作,重点介绍了选择性败育发生的式样、导致选择性败育的因素、选择性败育的进化生态意义,以及目前研究选择性败育现象的主要方法,并对该领域今后研究前景进行了展望。     

被子植物地下结实和地上/下两型结实的生态适应意义

地下结实和地上/下两型结实是被子植物两类独特的结实方式, 多发生在陆生和草本植物中, 主要生长在缺少水分或光照、土壤扰动频繁及环境波动较为剧烈的生境中。两种结实方式不仅是植物适应性进化的重要方面, 也是选择性进化的产物。其中, 地下结实对于植物在母株附近适宜微环境中保存后代、在极端环境下保持种子活力、逃避地面动物取食和火灾伤害以及延长果实发育时间等方面, 地上/下两型结实对于减少同胞子代及种群内竞争、维持和扩大种群以及提高物种的适应力和进化可塑性等方面, 都具有重要的生态适应意义, 是植物抵御不利生物与非生物环境的两类重要防御策略。但两种结实方式同时也存在着限制果实与种子扩散、影响基因传递与种群遗传结构、加大种群隔离以及提高繁殖代价等进化限制, 对物种的分布、种群增长、迁移、适合度和生活史进化等具有重要影响。目前, 地下和地上/下两型结实现象分别在大约24科57属和13科34属中进行了报道, 其中在菊科、十字花科、豆科和玄参科等类群中两种结实现象同时存在。从系统发育看, 地下结实在木兰分支、单子叶植物分支及双子叶植物分支中均存在, 而地上/下两型结实仅出现在单子叶植物分支和双子叶植物分支中, 在被子植物基部类群(ANITA类群)中两种结实方式均不存在。该文对植物地下和地上/下两型结实的类型、系统进化、繁殖特性和扩散对策进行了介绍, 并对其生态适应意义进行了总结, 以期为深入研究植物结实的进化策略提供参考。     

沙丘稀有种准噶尔无叶豆花部综合特征与传粉适应性

植物花部特征进化与传粉适应性一直是进化生态学领域关注的核心问题之一。以古尔班通古特沙漠自然生长的准噶尔无叶豆为对象,对其花部特征和传粉特性进行了野外观察和室内的分析研究。结果表明:种群花期历时21 d,花序花期历时7-12 d,单花花期一般3 d,若遇阴雨天气,花期可延长1-2 d,整个花期龙骨瓣一直保持闭合状态。单花10枚花药在旗瓣微张时已全部完成散粉。准噶尔无叶豆主要靠分泌花蜜、鲜艳的花色以及旗瓣基部的黄色辐射状纹理结构吸引传粉者。准噶尔无叶豆花期的有效传粉者为4种蜂类昆虫,它们的平均访花频率为(7.75±0.57)次·花^-1·d^-1,访花高峰期表现为三峰型: 13:00-14:00,16:00-17:00和19:00-20:00。准噶尔无叶豆人工套袋实验表明该种为自交亲和型,主动自交少见,生殖成功依赖传粉者。胚珠成功受精至果实完全成熟阶段存在自交衰退,柱头角质层结构和花粉刷结构是准噶尔无叶豆在进化过程中形成的减少自交,倾向异交的机制。     

Secondary metabolites from Eurotium species, Aspergillus calidoustus and A. insuetus common in Canadian homes with a review of their chemistry and biological activities

As part of studies of metabolites from fungi common in the built environment in Canadian homes, we investigated metabolites from strains of three Eurotium species, namely E. herbariorum, E. amstelodami, and E. rubrum as well as a number of isolates provisionally identified as Aspergillus ustus. The latter have been recently assigned as the new species A. insuetus and A. calidoustus. E. amstelodami produced neoechinulin A and neoechinulin B, epiheveadride, flavoglaucin, auroglaucin, and isotetrahydroauroglaucin as major metabolites. Minor metabolites included echinulin, preechinulin and neoechinulin E. E. rubrum produced all of these metabolites, but epiheveadride was detected as a minor metabolite. E. herbariorum produced cladosporin as a major metabolite, in addition to those found in E. amstelodami. This species also produced questin and neoechinulin E as minor metabolites. This is the first report of epiheveadride occurring as a natural product, and the first nonadride isolated from Eurotium species. Unlike strains from mainly infection-related samples, largely from Europe, neither ophiobolins G and H nor austins were detected in the Canadian strains of A. insuetus and A. calidoustus tested, all of which had been reported from the latter species. TMC-120 A, B, C and a sesquiterpene drimane are reported with certainty for the first time from indoor isolates, as well as two novel related methyl isoquinoline alkaloids.     

Distribution, structural and ecological aspects of the unusual leaf nectaries of Calolisianthus species (Gentianaceae)

Nectaries in leaves of Gentianaceae have been poorly studied. The present study aims to describe the distribution, anatomy, and ecological aspects of extrafloral nectaries (EFNs) of three Calolisianthus species and in particular the ultrastructure of EFNs in Calolisianthus speciosus during leaf development, discussing its unusual structure. Leaves of Calolisianthus species were fixed and processed by the usual methods for studies using light, scanning microscopy and transmission electron microscopy (TEM). Ion chromatography was used to analyze the nectar exudates of C. speciosus. The distribution patterns of nectar secretion units were analysed by ANOVA and t-tests. Two EFNs that can be seen macroscopically were observed at the bases of C. speciosus and C. pendulus leaves. Such large nectaries are absent there in C. amplissimus. Another similarly large EFN is observed at the apex of each leaf in all species. The EFNs at the base of the young leaves in C. speciosus are visited by ants during the rainy season. EFNs are formed by several nectar secretory units (nectarioles) that are present throughout the leaves. Each nectariole is formed by rosette cells with a central channel from which the nectar is released. Channels of old C. speciosus and C. pendulus EFNs were obstructed by fungi. TEM of EFNs in young leaves showed cytoplasms with secretion, small vacuoles, mitochondria, cell wall ingrowth, and plasmodesmata. TEM of EFNs in old leaves demonstrated dictyosomes, plastids, mitochondria, segments of endoplasmatic reticulum, and lipid droplets. The nectar contains sucrose, glucose and fructose.     

荒漠植物白刺属4个物种的生殖分配比较

选定乌兰布和沙漠地区白刺属4种植物为研究对象,通过对其样株在花期的各生殖构件的数量特征及生物量调查,系统研究了唐古特白刺(Nitraria tangutorum Bobr.)、西伯利亚白刺(Nitraria sibirica Pall.)、大白刺(Nitraria roborowskii Kom.)和泡泡刺(Nitraria sphaerocarpa Maxim.)4种白刺属植物在生殖枝水平上的生殖分配。结果表明:不同白刺属植物在分株高度、生殖枝长、生殖枝基径、单枝花数、花序干重、枝叶干重等生殖构件的数量性状方面均有显著差异,其中泡泡刺的各生殖构件的数量均最小;除了西伯利亚白刺的生殖分配值达到44.51%外,其余3种白刺的生殖分配值均没有超过20%。经统计分析,4种白刺种群的生殖枝长分别与分株高度呈显著(P<0.05)的直线性正相关关系;生殖枝花序干重与分株高显著正相关;4种白刺的生殖分配随着分株生殖枝生物量的增加而减少,即白刺的个体大小与生殖分配之间呈现负相关关系。这种生殖分配特点反映了不同白刺植物对生长环境的资源利用、与克隆繁殖的权衡及对生态适应的策略。     

Prenylated flavanones and flavanonols as chemical markers in Glycosmis species (Rutaceae)

Fifteen prenylated or geranylated flavanones and flavanonols were isolated from the leaf extracts of different Glycosmis species collected in Thailand and Malaysia. All structures were elucidated by spectroscopic methods, especially 1D and 2D NMR. Six compounds were described for the first time and two were only known so far as synthetic products. The chemotaxonomic significance of flavanoid accumulation within the genus Glycosmis is highlighted.     

RPB2 sequences reveal a close phylogenetic relationship between tetraploid Hordelymus and diploid Hordeum species in Triticeae (Poaceae)

The origin of Hordelymus genome has been debated for years, and no consensus conclusion was reached. In this study, we sequenced and analyzed the RPB2 (RNA polymerase subunit II) gene from Hordelymus europaeus (L.) Harz, and its potential diploid ancestor species those were suggested in previous studies. The focus of this study was to examine the phylogenetic relationship of Hordelymus genomes with its potential donor Hordeum, Psathyrostachys, and Taeniatherum species. Two distinguishable copies of sequences were obtained from H. europaeus. The obvious difference between the two copies of sequences is a 24 bp indel (insertion/deletion). Phylogenetic analysis showed a strong affinity between Hordeum genome and Hordelymus with 85% bootstrap support. These results suggested that one genome in tetraploid H. europaeus closely related to the genome in Hordeum species. Another genome in H. europaeus is sister to the genomes in Triticeae species examined here, which corresponds well with the recently published EF-G data. No obvious relationship was found between Hordelymus and either Ta genome donor, Taeniatherum caput-medusae or Ns genome donor, Psathyrostachys juncea. Our data does not support the presence of Ta and Ns genome in H. europaeus, and further confirms that H. europaeus is allopolyploid.     

Chemical constituents of the seeds of Ammopiptanthus (Leguminosae) and their systematic and ecological significance

Eleven flavonoids including a new flavone glycoside, 7,3′-dihydroxy-4′-methoxyflavone-7-O-β-glucopyranoside, and a quinolizidine alkaloid, lupanine, were isolated from the seeds of two Ammopiptanthus (Leguminosae) species, Ammopiptanthus mongolicus and Ammopiptanthus nanus. 7,3′-Dihydroxy-4′-methoxyflavone and lupanine were the major constituents in the seeds of both species. The patterns of seed flavonoids presented a clear systematic relationship between the two species. The simple seed alkaloid composition was presumed to be responsible for the weak defense capability of the seeds to insect pests in both species.     

Flavonoids in the species of Cyrtomium (Dryopteridaceae) and related genera

Flavonoids in 19 Cyrtomium, three Cyrtogonellum and two Phanerophlebia taxa were surveyed. Major flavonoids were flavonol O-glycosides based on kaempferol, quercetin, and sometimes myricetin, and C-glycosylflavones, such as isovitexin, vitexin, isoorientin, orientin and their O-glycosides. The C-methylflavanones, farrerol and cyrtominetin, and their 7-O-glucosides were isolated from Cyrtomium devexiscapulae and Cyrtomium laetevirens. Flavanones have been reported from Cyrtomium falcatum sensu lato. Though C. falcatum sensu lato is divided into four taxa, i.e. C. falcatum subsp. falcatum, C. falcatum subsp. australe, C. falcatum subsp. littorale, and C. devexiscapulae, the occurrence of the flavanones was restricted to C. devexiscapulae, and they did not occur in C. falcatum sensu stricto.