Effects of oxygen level on metabolism and development of seedlings of Trapa natans and two ecologically related species

Seeds of the water plant Trapa natans L. (water chestnut) can germinate in strict anoxia. The seedlings show seminal roots growing upwards while shoot buds remain quiescent until O₂ becomes available. Trapa seedlings are highly tolerant to anoxia. The rate of ethanol fermentation was 21.2 μmol (g FW)⁻¹ h⁻¹, while production of lactate was negligible and lower than that of succinate. The seminal root of Trapa compares better to the rice coleoptile rather than to the rice root, both functionally and as to the metabolic response to anoxia. The anaerobic germination of Nuphar luteum L. and Scirpus mucronatus L. was also characterized by a limited developmental program.     

The structure of the littoral: effects of waterlily density and perch predation on sediment and plant‐associated macroinvertebrate communities

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Phylogenetic relationships in Nuphar (Nymphaeaceae): evidence from morphology,chloroplast DNA,and nuclear ribosomal DNA

The genus Nuphar consists of yellow-flowered waterlilies and is widely distributed in north-temperate bodies of water. Despite regular taxonomic evaluation of these plants, no explicit phylogenetic hypotheses have been proposed for the genus. We investigated phylogenetic relationships in Nuphar using morphology and sequences of the chloroplast gene matK and of the internal transcribed spacer (ITS) regions of nuclear ribosomal DNA. Two major lineages within Nuphar are consistently resolved with the morphological and molecular data sets. One lineage comprises New World taxa and the other represents a primarily Old World lineage. Relationships within the major lineages were poorly resolved by morphology and ITS, yet certain relationships were elucidated by all analyses. Most notable is the strong support for a monophyletic lineage of dwarf taxa and the alliance of the North American N. microphylla with the Eurasian taxa. Minor discordance between the independent cladograms is accounted for by hybridization. The common taxonomic practice of uniting all North American and Eurasian taxa under one species is not supported phylogenetically.     

Expression of floral MADS-box genes in basal angiosperms: implications for the evolution of floral regulators

The ABC model of floral organ identity is based on studies of Arabidopsis and Antirrhinum, both of which are highly derived eudicots. Most of the genes required for the ABC functions in Arabidopsis and Antirrhinum are members of the MADS-box gene family, and their orthologs are present in all major angiosperm lineages. Although the eudicots comprise 75% of all angiosperms, most of the diversity in arrangement and number of floral parts is actually found among basal angiosperm lineages, for which little is known about the genes that control floral development. To investigate the conservation and divergence of expression patterns of floral MADS-box genes in basal angiosperms relative to eudicot model systems, we isolated several floral MADS-box genes and examined their expression patterns in representative species, including Amborella (Amborellaceae), Nuphar (Nymphaeaceae) and Illicium (Austrobaileyales), the successive sister groups to all other extant angiosperms, plus Magnolia and Asimina, members of the large magnoliid clade. Our results from multiple methods (relative-quantitative RT-PCR, real-time PCR and RNA in situ hybridization) revealed that expression patterns of floral MADS-box genes in basal angiosperms are broader than those of their counterparts in eudicots and monocots. In particular, (i) AP1 homologs are generally expressed in all floral organs and leaves, (ii) AP3/PI homologs are generally expressed in all floral organs and (iii) AG homologs are expressed in stamens and carpels of most basal angiosperms, in agreement with the expectations of the ABC model; however, an AG homolog is also expressed in the tepals of Illicium. The broader range of strong expression of AP3/PI homologs is inferred to be the ancestral pattern for all angiosperms and is also consistent with the gradual morphological intergradations often observed between adjacent floral organs in basal angiosperms.     

瑶药冷骨风质量控制方法研究

瑶药冷骨风来源于睡莲科植物萍蓬草(Nuphar pumilum)的干燥根茎,为瑶族人习用药材,具有止咳补虚、除蒸止汗、祛瘀调经、止血的作用,目前历版《中国药典》和地方标准并未有收载其质量控制方法。该研究收集了10批冷骨风药材,采用生药鉴别方法对冷骨风药材性状进行显微鉴别,用TLC(薄层色谱)法对药材进行定性鉴别,用高效液相色谱法对没食子酸含量进行测定。结果表明:(1)色谱柱为Welch Ultimate XB-C_(18)柱(4.6 mm×250 mm,5μm),流动相为甲醇-0.05%磷酸溶液(5∶95),流速为1.0 mL·min~(-1),检测波长为272 nm,柱温为室温。(2)建立了冷骨风药材性状、显微、TLC鉴别方法。(3)含量测定中没食子酸在0.072 1~0.360 5μg范围时,进样量与峰面积呈良好的线性关系,平均回收率为103.66%,RSD为2.03%(n=6)。(4)10批样品没食子酸含量为0.82%~1.23%,平均含量为0.94%。因此,建立的瑶药冷骨风质量控制方法具有较强的科学性,可用于冷骨风药材的质量控制。     

Atomic Force Microscope Information on Pollen Exine Substructure in Nuphar

Images of individual exine units from the tectum of Nuphar luteum (L.) Sm. pollen were made using atomic force microscopy. These units were recorded as being 120 to 160 nm wide. Exine-units sectioned transversally were circular and had a central circular (core) zone 40 nm or more in diameter. Exine unit-structures in Nuphar have an outer (binder) substructure coiled around a core zone.     

Small-scale distributional dynamics of the yellow water-lily and its herbivore Galerucella nymphaeae (Coleoptera: Chrysomelidae)

Summary I followed the within-generation distribution of a chewing specialist herbivore, the water-lily beetle, on individually marked leaves of the yellow water-lily. Yellow water-lilies produced new leaves steadily throughout the growth season. Average leaf longevity was 3–4 weeks, much shorter than the developmental time of the beetle. The average egg-load of leaves was about 120. Leaf longevity was independent of egg density, but migration rate of the first instar larvae was density-dependent. Beetles occurred in every leaf, but consumed only a fraction (17%) of the available leaf area. However, this caused the leaf to lose its floating ability, so even this low rate of consumption made the leaf unavailable to herbivores. The herbivore population had to redistribute itself throughout the summer, escaping from the drowning leaves to fresh ones. No beetle could survive from egg to adult on a single leaf. The small-scale redistribution of the herbivore strongly affected the damage experienced by the host plant. In general, ability to redistribute depends on the dispersal ability of the herbivore, and thus migration ability may strongly affect the plant-herbivore interaction.     

Floral biology of Nuphar pumila (Timm) DC. (Nymphaeaceae) in China

Anthesis in individual flowers of Nuphar pumila (Timm) DC. occurs for four consecutive days. First-day flowers are protogynous and functionally female. Flowers can open completely on the first day of anthesis. This contrasts with all previous reports, which state that first-day flowers of Nuphar are characterized by partial expansion of the calyx, leaving a distal small triangular opening just above the stigmatic disc. Flowers close completely on the first night of anthesis and remain partially open on the subsequent three nights. During the entire anthesis period the stigmas emit a sweet, fruity odor and the petal nectaries produce visible nectar drops. The stigma of N. pumila is secretory and unicellular-papillate. Pollen grains are monosulcate with long spines. Our observations on the mating system of N. pumila indicate that neither asexual seed production nor spontaneous self-pollination occurs. Cross-pollination of second-, third- and fourth-day flowers produced few seeds. Flowers of N. pumila were mainly pollinated by sweat bees, with flies playing a minor pollination role. No beetle visits were observed. Our insect-pollination observations substantiate the view that the relative contribution of flies, bees, and beetles to pollination in a single Nuphar population depends on two factors: the relative abundance of the insects, and presence of alternative food sources.