The Ability of Tetrahymena utriculariae (Ciliophora,Oligohymenophorea) to Colonize Traps of Different Species of Aquatic Carnivorous Utricularia

The host specificity of the recently described ciliate species Tetrahymena utriculariae was tested in a greenhouse growth experiment, which included 14 different species of aquatic Utricularia as potential host plants. We confirmed the high specificity of the interaction between U. reflexa and T. utriculariae, the former being the only tested host species able to maintain colonization for prolonged time periods. We conclude that this plant–microbe relationship is a unique and specialized form of digestive mutualism and the plant–microbe unit a suitable experimental system for future ecophysiological studies.     

中国神农架蜡梅属一新变种和新变型

描述了蜡梅（Chimonanthus praecox L.）一新变种即卷瓣蜡梅,该变种与原变种的主要区别是中花被片高度反卷,中被片颜色为白色或金黄色,主要分布于神农架林区。其中中被片颜色为白色的卷瓣蜡梅可以被看作一个新变型跳枝蜡梅。     

Internal architecture, origin-insertion site, and mass of jaw muscles in Old World hamsters

The jaw muscle (i.e., masticatory, suprahyoid, and extrinsic tongue) anatomy and mass were examined in four genera of Old World hamsters (cricetine murids), Mesocricetus, Cricetulus, Tscherskia, and Phodopus. The masseter was the largest and most complicated of the muscles examined. In the superficial layer, a few ventral fibers form a small medially turned portion with an insertion site more similar to those of sciurids than of other murids. In Mesocricetus, the superficial layer has a discrete anteroventral portion that has not been reported for other murid rodents. Examination of the fiber attachment sites indicated that the deep layer contains four parts and the medial layer contains three parts. The deep layer originates from two aponeuroses that are firmly connected to each other at their anterior ends and lie along the zygomatic arch. The aponeurosis of insertion for the deep layer is situated along the masseteric ridge and the dorsal border of the angular process, but is absent in its middle part, consistent with reports in two relatives, sigmodontine and arvicoline murids. In cricetine murids, unlike in other rodents, fibers insert on the dorsal narrow strip of the posterior mandibular aponeurosis, not on its broad medial aspect. The relative mass of some masticatory and suprahyoid muscles is related to body mass. Small species (Cricetulus and Phodopus) have relatively larger masseter and mylohyoid muscles and smaller temporalis and geniohyoid muscles than large species (Mesocricetus and Tscherskia).     

Mineral cost of carnivory in aquatic carnivorous plants

Tissue N, P, K, Ca, and Mg content was estimated in traps and photosynthetic and carnivorous shoots in five aquatic carnivorous plant species from an outdoor culture: Aldrovanda vesiculosa, Utricularia vulgaris, U. reflexa, U. intermedia, and U. stygia, for the determination of the mineral cost of carnivory. In three species with monomorphic shoots (A. vesiculosa, U. vulgaris, U. reflexa), tissue P and K content in traps was significantly higher than that in their photosynthetic shoots, whereas N content was about the same. In U. stygia and U. intermedia with dimorphic shoots, tissue N and P content was markedly the highest in photosynthetic shoots followed by traps, while it was lowest in carnivorous shoots. In all five species, trap K content was significantly (2–4 times) higher than that in photosynthetic and carnivorous shoots. In all species, the values of the mineral cost of carnivory – the proportion of mineral nutrient amount contained in traps or carnivorous shoots to that in the total plant biomass – were within 19–61% for N, 33–76% P, 51–78% K, 26–70% Ca, and 34% for Mg. A new concept of the ecological cost-benefit relationships of plant carnivory, based on the mineral benefit of prey capture and mineral costs associated with trap production, is introduced for aquatic carnivorous plants. The evolution of this plant group is considered to show the optimization of these mineral cost-benefit relationships.     

Genetic structure in aquatic bladderworts: clonal propagation and hybrid perpetuation

• Background and Aims The free-floating aquatic bladderwort Utricularia australis f. australis is a sterile F₁ hybrid of U. australis f. tenuicaulis and U. macrorhiza. However, co-existence of the hybrids and parental species has not been observed. In the present study, the following questions are addressed. (a) Does the capacity of the two parental species to reproduce sexually contribute to higher genotypic diversity than that of sterile F₁ hybrid? (b) Are there any populations where two parental species and their hybrid co-exist? (c) If not, where and how do hybrids originate?• Methods The presence and absence of Utricularia was thoroughly investigated in two regions in Japan. An amplified fragment length polymorphism (AFLP) analysis was conducted for 397 individuals collected from all populations (33 in total) where Utricularia was observed.• Key Results The mean number of genotypes per population (G) and genotypic diversity (D) were extremely low irrespective of the capacity to reproduce sexually: G was 1·1–1·2 and D was 0·02–0·04. The hybrid rarely co-existed with either parental species, and the co-existence of two parental species was not observed. Several AFLP bands observed in the hybrid are absent in both parental genotypes, and parent and hybrid genotypes in the same region do not show greater genetic similarity than those in distant regions.• Conclusions The capacity to reproduce sexually in parental species plays no role in increasing genotypic diversity within populations. The observed genotypes of the hybrid could not have originated from hybridization between the extant parental genotypes within the study regions. Considering the distribution ranges of three investigated taxa, it is clear that the hybrid originated in the past, and hybrid populations have been maintained exclusively by clonal propagation, which may be ensured by both hybrid vigor and long-distance dispersal of clonal offspring.     

Alternate paths of evolution for the photosynthetic gene rbcL in four nonphotosynthetic species of Orobanche

We have determined the nucleotide sequence for the Rubisco large subunit from four holoparasitic species of Orobanche. Intact open reading frames are present in two species (O. corymbosa and O. fasciculata), whereas the remaining species (O. cernua and O. ramosa) have rbcL pseudogenes. Sequences for rbcL 5'-UTRs from species of Orobanche have few changes in the promoter and ribosome binding sites compared to photosynthetic higher plants. Comparison of rbcL 3'-UTR sequences for Nicotiana, Ipomoea, Cuscuta, and Orobanche reveal that nucleotide sequences from parasitic plants have regions capable of forming stem-loop structures, but 56–69 nt are deleted upstream of the stem-loop in the parasitic plants compared to their photosynthetic relatives. Although rbcL pseudogenes of O. cernua and O ramosa have many large and small deletions, few indels are shared in common, implying that their common ancestor probably had an intact rbcL reading frame. Intact rbcL reading frames in O. corymbosa and O. fasciculata retain a bias of synonymous over nonsynonymous substitutions and deduced protein sequences are consistent with potentially functional Rubisco large subunit proteins. A conservative model of random substitution processes in pseudogene sequences estimates that the probability is low (P<0.028) that these sequences would retain an open reading frame by chance. Species of Orobanche have either had recent photosynthetic ancestors, implying multiple independent losses of photosynthesis in this genus, or the rbcL gene may serve an unknown function in some nonphotosynthetic plants.     

Six New Species and One New Subspecies of Codonopsis(Campanulaceae) from the Pan Himalaya

Six species and one subspecies of Codonopsis are described from the Pan Himalaya as new in the present article. They are Codonopsis bomiensis, Ccampanulata, Celliptica, Chemisphaerica, Clixianica, Creflexa, and Ccardiophylla Diels ex Kom. subsp. megaphylla. The six new species each is provided with an illustration.     

Photosynthetic CO2 affinity of the aquatic carnivorous plant Utricularia australis (Lentibulariaceae) and its investment in carnivory

Aquatic carnivorous plants usually grow in shallow dystrophic waters poor in inorganic N and P. Utricularia australis was chosen as a model plant for its prolific distribution and great ecological plasticity. The photosynthetic CO₂ compensation point and factors associated with investment in carnivory and capture of prey were measured in 17 U. australis micropopulations in Třeboň basin, Czech Republic, together with water chemistry factors at these sites differing greatly in their trophic level, water hardness, and prey availability. Apical shoot growth rate was estimated at some oligotrophic sites. The micropopulations differed greatly in the proportion of traps with animal prey (2.7–70%, mean 26%), trap proportion to total biomass (1.4–42%, mean 26%), mean trap biomass (0.7–63 μg trap⁻¹, mean 19 μg), and maximum trap size (1–3 mm, mean 2.0 mm). CO₂ compensation points ranged from 0.7 to 6.1 μM (mean 2.6 μM). A weak HCO₃ ⁻ use (compensation point 0.51 mM) was found in plants growing in alkaline water. Trap biomass proportion did not correlate significantly with prey capture and CO₂ compensation points with ambient [CO₂]. A very rapid apical growth (2.5–4.2 new nodes day⁻¹) occurred in sand pits. Thus, HCO₃ ⁻ use in U. australis can be induced by growing at very high pH. CO₂ compensation points resembled those known in other aquatic non-carnivorous plants. They did not reflect carnivory. In spite of very rapid apical shoot growth, the relative growth rate of U. australis can be zero in oligotrophic habitats without prey.     

泛喜马拉雅地区党参属六个新种和一个新亚种

描述了在泛喜马拉雅地区发现的党参属六个新种和一个新亚种。Codonopsis campanulata和C．reflexa 分布于尼泊尔,C．bomiensis发现于西藏的波密和米林,其余都产自四川西部。六个新种均附有精美的线条图。