点叶绵枣叶片培养及器官分化的研究

点叶绵枣叶外植体培养于MS 6-BA 1 PPm IBA 0.5 ppm培养基中,一月后不定芽仅从近轴面的叶表面产生。组织学的观察表明,不定芽起源于表皮细胞。     

Biliprotein assembly in the disc-shaped phycobilisomes of Rhodella violacea electron microscopical and biochemical analyses of C-phycocyanin and allophycocyanin aggregates

C-phycocyanin and allophycocyanin from the red alga Rhodella violacea were investigated by electron microscopy and biochemical methods using samples taken from the same fractions.The molecular weights of the native biliprotein aggregates C-phycocyanin and allophycocyanin are about 139,000 (140,000) and 130,000 (145,000) as revealed by calibrated gel chromatography, gradient gel electrophoresis and morphological measurements on the basis of an average protein packing density. These molecular weights are direct evidence for a trimeric aggregation form ()₃ of these biliproteins. Independently, their monomers were determined to be about 34,400 (C-phycocyanin) and 33,900 (allophycocyanin).C-phycocyanin and allophycocyanin are ringshaped, six-membered, biliprotein aggregates with dimensions of about 10.2×3.0 nm and 10.0×3.0 nm, respectively. The aggregates are made up of six subunits, 3 and 3, which are assumed to be associated in alternating positions. They are arranged in regular hexagons in C₆ symmetry. Hexameric aggregates ()₆, so far only isolated for C-phycocyanin, originate by face to face association of two trimeric aggregates.     

A Stereoselective Synthesis of Antimycinone A3 and Its Stereoisomers

Antimycinone A₃, which is a neutral fragment of mild alkaline hydrolysate of antimycin A₃, and its stereoisomers were synthesized stereoselectively from methyl trans-2-n-butylpent-3-enoate or methyl cis-2-n-butylpent-3-enoate, and natural antimycinone A₃ was proved to possess Hα-Hβ and Hβ-Hγ trans configuration.     

The effect of ultraviolet-depleted light on the flavonol contents of the cactus species Opuntia wilcoxii and Opuntia violacea

An early investigation at the Biosphere-2 Laboratory, an artificial ecosystem in the Arizona desert, had shown that the flavonoid content of cacti grown in glass-filtered solar light was lower than of cacti grown in normal solar light. This was attributed to the absence of ultraviolet (UV) radiation, which is required for flavonoid biosynthesis. In this study, two species of Opuntia cacti were grown in solar and UV-depleted light, and their flavonol contents of different tissues were determined by HPLC. O. wilcoxii, previously raised in the absence of UV light, was exposed to normal solar light. The flavonol content of young O. wilcoxii pads was 28-fold higher when grown in solar light as compared to UV-depleted light. The flavonol contents of mature outer tissues were only slightly higher. O. violacea, previously raised in solar light, was also maintained in the same UV-depleted artificial ecosystem. The flavonol content after hydrolysis of outer tissues was similar, whether grown in solar light or UV-depleted light. We attribute these responses to different biosynthetic and metabolic rates of young vs. mature plant tissues; slow-growing mature tissues neither produce nor metabolize compounds as quickly as immature tissues. These findings indicate that artificial ecosystems can influence the production of natural products in cultivated plants.     

Riccia fruticulosa O.F.Müll., 1782 and blue Metzgeria (Marchantiophyta) in Europe

Riccia fruticulosa O.F.Müll., 1782 from Norway is a valid name, referring to Riccardia palmata (Hedw.) Carruth. In 1785 Dickson misidentified British plants of a blue Metzgeria as R. fruticulosa . The European blue species of Metzgeria is conspecific with M. violacea (Ach.) Dumort., which replaces M. fruticulosa auct. The true origin of the type of Jungermannia violacea Ach., 1805 is probably Tierra del Fuego (rather than Dusky Bay, New Zealand), where the species is widespread. Reports from Australasia, Asia and Africa are all erroneous. The blue colour of Jungermanniales is found only in living plants and is derived from the oil-bodies. In contrast, that of Metzgeria appears only after death; its biological function is unknown.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 142 , 229−235.     

The influence of plant spacing on density-dependent versus frequency-dependent spore transmission of the anther smut Microbotryum violaceum

The anther smut fungus Microbotryum violaceum is a pollinator-transmitted plant disease. As for other vector-borne diseases, frequency-dependent transmission patterns are predicted, in contrast to the density-dependent transmission of passively spread diseases. Frequency dependence will, however, only arise if vectors compensate for varying plant spacings. To test this assumption, we set up experimental populations of the host plant, Silene latifolia, with varying disease density (number of diseased plants per plot) and frequency (proportion of plants diseased), and three different plant spacings. We measured spore deposition on healthy flowers in these plots on two dates. Spore deposition decreased considerably from the first to the second census, perhaps related to the concomitant decrease in inflorescence sizes of diseased plants. At our first census, spore deposition rates varied with disease frequency, and the effect of frequency depended on plant spacing. While spore deposition was positively frequency dependent at the 1.5-m inter-plant spacing, no effect of disease frequency was found at a spacings of 0.5 m or 3 m. Nor was there an effect of disease density on spore deposition at the first census. At the later census, on the other hand, spore deposition increased almost significantly with increasing disease density (P = 0.08). This difference in deposition pattern together with a significant decrease in spore receipt indicates changes in pollinator spectrum and/or activity. The correlation of spore numbers among flowers within plants, an indication for intra-plant moves by vectors, was significant at 0.5 m and 1.5 m but not at 3 m. Floral traits and sex of individual plants influenced the number of spores they received. On the first census date, spore deposition increased with increasing inflorescence size in female but not in male plants. On the second census date, neither sex nor number of open flowers had an effect on spore receipt. None of the experimental plants became infected, however, probably because of the unusually hot and dry weather. Received: 14 May 1998 / Accepted: 19 November 1998     

珍稀濒危物种堇叶紫金牛高效快繁体系的建立

筛选堇叶紫金牛(Ardisia violacea)野生优株,以其当年新发带休眠腋芽茎段为外植体,通过启动培养、丛生芽诱导增殖、壮苗培养、生根培养和炼苗移栽等过程建立其组培快繁技术体系。研究结果表明,最佳启动培养基为MS+0.80 mg·L~(–1)KT+0.10 mg·L~(–1) NAA+0.10 mg·L~(–1) IBA,腋芽萌发率达92.60%;最佳丛生芽诱导增殖培养基为MS1+0.50 mg·L~(–1) TDZ+0.10mg·L~(–1) NAA,平均增殖系数达8.60;最佳壮苗培养基为MS+1.00 mg·L~(–1) KT+0.50 mg·L~(–1) NAA;最佳生根培养基为1/2MS+2.00 mg·L~(–1) IBA+1.00 mg·L~(–1) NAA+1.00 mg·L~(–1) AC,平均生根率达98.70%;采用松鳞和泥炭(2:1,v/v)作为炼苗基质,炼苗成活率可达85.30%。实验成功建立了堇叶紫金牛高效组培快繁技术体系,经验证该体系能够满足规模化生产的需求。     

SYNTHESIS AND BINDING OF PHYCOERYTHRIN AND ITS ASSOCIATED LINKERS TO THE PHYCOBILISOME IN RHODELLA VIOLACEA (RHODOPHYTA): COMPARED EFFECTS OF HIGH LIGHT AND TRANSLATION INHIBITORS1

We studied the synthesis and binding of phycoerythrin and its associated linkers to the phycobilisome (PBS) in Rhodella violacea (Kornmann) Wehrmeyer and compared the effects of high light and translation inhibitors on these processes. Rhodella violacea has a simple hemidiscoidal PBS structure with a well-known composition. The number of PBSs per cell decreases when irradiance is increased, and at higher irradiances the rods are shortened with a specific loss of the terminal hexamer of phycoerythrin (PE) and its associated linker. To test whether or not the observed variations were due to a coordination between the expression of the chloroplast-encoded PE and the nuclear-encoded linkers, we inhibited the expression of the chloroplast genes by the translation inhibitor chloramphenicol. In the few PBSs synthesized, the linker associated to the terminal PE hexamer was missing while that associated with the intermediate PE hexamer was still present. The inhibition by cycloheximide of the translation of the nuclear-encoded linkers did not influence the synthesis of the chloroplast-encoded phycobiliproteins. The absence of linkers prevented the formation of PE hexamers and their binding to the PBSs. We therefore propose the existence of two levels of regulation for PE and associated linkers: the intermediate PE hexamer and associated linker are always present even though their amount is reduced when irradiance is increased. In contrast, the terminal hexamer of PE and its associated linker are no longer present under high light. Their absence can be due to a feedback control between the level of PE and the synthesis of the linker: when the level of PE is lowered below a given value by the action of light on the chloroplast, a signal coming from the chloroplast reaches the nucleus and the synthesis of the linker is repressed. There is no sign of nuclear regulation of the synthesis of PE, but the nuclear-encoded linkers have a structural role in the formation of PE hexamers.     

Corynoplastis japonica gen. et sp. nov. and Dixoniellales ord. nov. (Rhodellophyceae,Rhodophyta) based on morphological and molecular evidence

A new unicellular red alga, Corynoplastis japonica gen. et sp. nov., is described from Tobishima, Japan. Cells are spherical, 18–33 µm in diameter, pale purple to brownish red and surrounded by a mucilaginous sheath. A single chloroplast with many lobes extends from the cell periphery to the cell center. A peripheral thylakoid is present. A pyrenoid occurs at each innermost chloroplast lobe end and one or two thylakoids are present in the pyrenoid matrix. The nucleus is eccentric to peripheral and Golgi bodies are scattered throughout the cell and associated with endoplasmic reticulum. Cells have a slow random gliding motility. The low molecular weight carbohydrate mannitol is present in the cells. Molecular phylogenetic analysis indicates that this alga is closely related to members of the genus Rhodella. A new order, Dixoniellales, is established for Dixoniella, Neorhodella and Glaucosphaera based on molecular and ultrastructural evidence (Golgi bodies associated only with the nucleus). The redefined order Rhodellales in which Rhodella and Corynoplastis are placed is characterized ultrastructurally by Golgi bodies scattered throughout the cytoplasm and associated with endoplasmic reticulum.     

稀土元素铕和钇对紫叶酢浆草试管苗生长的影响

在MS培养基中添加不同浓度的稀土元素铕(Eu)、钇(Y),研究Eu、Y对紫叶酢浆草试管苗生长的影响。结果表明,适宜浓度的Eu或Y能够促进紫叶酢浆草试管苗的生长和分化,但高浓度的Eu或Y则抑制紫叶酢浆草试管苗生长。