Woody Polygonaceae from Brazil: new species and a new interpretation

Three new species, Ruprechtia maracaensis, Ruprechtia nitida , and Triplaris matogrossensis are described. Ruprechtia glauca is a poorly known species from the state of Bahia. Its relationship with R. laxiflora is discussed.     

Inflorescence structure and generic delimitation of Triplaris and Ruprechtia (Polygonaceae)

A revision of the generic limits between Triplaris and Ruprechtia (Polygonaceae), which were confused in earlier literature, led to the conclusion that the two genera should be maintained. Triplaris is characterized by 1–flowered pistillate partial inflorescences, absence of a basal pedicel–like extension of the fruiting perianth–tube, which is always as long as or longer than the achene, bracteoles completely fissured on the abaxial side, and sessile or subsessile male flowers with perianth segments always connate for more than half of their length.
Ruprechtia has 2–3–flowered monochasial pistillate part–inflorescences (except the 1–flowered R. triflora) , a basal pedicel–like extension of the fruiting perianth–tube, which is at most 3/4 as long as the achene, more or less tubular bracteoles only exceptionally fissured down on the abaxial side, and pedicellate male flowers with perianth segments never connate for more than one third of their lenght. Preliminary paly–nological studies have shown that the pollen of Triplaris are microreticulate or punc–tate–microreticulate while Ruprechtia pollen have perforate–rugulose surfaces.     

不同遮阴环境下木奶果幼苗生长与生理生化的响应

木奶果是一种在幼苗期和成熟期对光适应性不同的热带乔木树种。研究不同遮阴环境下木奶果幼苗的生长及生理响应机制,以明确木奶果幼苗生长的适宜光照环境范围,对木奶果的苗木栽培及生态应用意义重大。本试验设置了5个处理,即CK(无遮阴),S3(遮光率45.3%)、S4(遮光率69.2%)、S6(遮光率80.0%)和S8(遮光率90.2%),观测停扣山和谢鞋山种源的木奶果幼苗4个月后的生长生理变化情况。结果显示:随着遮阴强度的加大,木奶果幼苗的叶面积与光合色素含量一直上升;叶绿素a/b值和过氧化氢酶(CAT)活性一直下降;丙二醛含量在S6前先呈下降趋势,而后稍有上升;株高和地径增长量先升后降,相对电导率、脯氨酸(Pro)与可溶性糖(Ss)含量则表现为先降后升。强光环境下,木奶果幼苗通过增加类胡萝卜素相对含量与CAT活性,以减缓膜脂过氧化损害;弱光环境下,木奶果幼苗通过增加叶面积与光合色素含量提高光能利用率。Pro与Ss则作为综合调节物,调节渗透压,以减轻强光与弱光带来的细胞膜胁迫压力。其中,停扣山与谢鞋山种源分别在S6与S4处理下Pro与Ss含量达最低值且株高与地径增长量达最高值。表明幼苗期的木奶果...     

Gerbera jamesonii, a New Host of Fusarium oxysporum f.sp. tracheiphilum

The random amplified polymorphic DNA (RAPD) technique was used to analyze the total genomic DNA of pathogenic isolates of Fusarium oxysporum on Gerbera jamesonii by comparing them to representatives of the formae speciales chrysanthemi and tracheiphilum. A close genetic relationship was observed among most of the new isolates from G. jamesonii. They shared RAPD markers with the tested representatives of the forma specialis chrysanthemi . Some isolates of those tested from diseased G. jamesonii were placed in a different cluster, which included representative isolates of forma specialis tracheiphilum . This is the first report of F. oxysporum f.sp. tracheiphilum on G. jamesonii. A rapid protocol for DNA extraction directly from fungal colonies grown on potato dextrose agar allowed complete analysis in less than 4 h.     

两种热带雨林树苗对环境光强变化的生理响应和适应机制

干季末雨季初以西双版纳热带雨林中木奶果和玉蕊2种树苗为材料,研究了将生长于12.5%自然光（相当于小林窗的光强）和36%自然光（相当于大林窗的光强）下的这2种树苗分别移至36%自然光和12.5%自然光下之后各自叶片最大净光合速率（Pmax）、叶绿素荧光参数、光合色素含量、比叶重（LMA）以及叶片悬挂角（MA）的变化过程,探讨了2种植物幼苗在生长环境光强改变后其形态和生理生态特性做出的相应调整以适应新的光环境的过程与机制。结果表明,这2种树苗均不适宜生长在大林窗的强光环境下,但木奶果对光环境的增强表现出一定的耐受力,光合适应潜力强于玉蕊,2种树苗对低光环境都能较好地适应;新叶的生成在整株植物对生长光环境变化的适应过程中也起到至关重要的作用。     

Foraging Behavior of the Parasitoid Encarsia formosa on Gerbera jamesonii Leaves

Insight into the foraging behavior of the parasitoid Encarsia formosa Gahan for whitefly hosts was gained by continuous observation of individual parasitoids on leaves of the ornamental plant Gerbera jamesonii, until females left the leaf. Comparison of the parasitoid behavior on three cultivars gave similar results. Mean searching time on uninfested G. jamesonii leaves of three cultivars was 1 h 30 min and the mean percentage of walking activity of the total observation time on those cultivars was 61%. Both parameters were not influenced by different leaf structures of Gerbera cultivars. Encounters with hosts arrested the parasitoids on the leaves. The walking activity and the percentage of host encounters that resulted in an oviposition decreased with decreasing egg load of the parasitoid. In comparison with tomato, where biological control of whiteflies is successful, only minor differences in the foraging behavior occur, except for the residence time of females, which was about three to four times longer on G. jamesonii leaves, but these leaves are about seven times larger than tomato leaves. The facts that (1) the foraging behavior of E. formosa on G. jamesonii is independant of the cultivar and (2) the foraging behavior is, in many aspects, similar to that on tomato suggest that biological control of whitefly on this ornamental plant is a potential option.     

Carbon monoxide enhances the chilling tolerance of recalcitrant Baccaurea ramiflora seeds via nitric oxide-mediated glutathione homeostasis

Both carbon monoxide (CO) and nitric oxide (NO) play fundamental roles in plant responses to environmental stress. Glutathione (GSH) homeostasis through the glutathione-ascorbate cycle regulates the cellular redox status and protects the plant from damage due to reactive oxygen species (ROS) or reactive nitrogen species (RNS). Most recalcitrant seeds are sensitive to chilling stress, but the roles of and cross talk among CO, NO, ROS, and GSH in recalcitrant seeds under low temperature are not well understood. Here, we report that the germination of recalcitrant Baccaurea ramiflora seeds shows sensitivity to chilling stress, but application of exogenous CO or NO markedly increased GSH accumulation, enhanced the activities of antioxidant enzymes involved in the glutathione-ascorbate cycle, decreased the content of H(2)O(2) and RNS, and improved the tolerance of seeds to low-temperature stress. Compared to orthodox seeds such as maize, only transient accumulation of CO and NO was induced and only a moderate increase in GSH was shown in the recalcitrant B. ramiflora seeds. Exogenous CO or NO treatment further increased the GSH accumulation and S-nitrosoglutathione reductase (GSNOR) activity in B. ramiflora seeds under chilling stress. In contrast, suppressing CO or NO generation, removing GSH, or blocking GSNOR activity resulted in increases in ROS and RNS and impaired the germination of CO- or NO-induced seeds under chilling stress. Based on these results, we propose that CO acts as a novel regulator to improve the tolerance of recalcitrant seeds to low temperatures through NO-mediated glutathione homeostasis.     

西双版纳野芭蕉先锋群落优势种群的生态位动态

运用Ｌｅｖｉｎｓ（１９６８）和Ｐｉａｎｋａ（１９７３）提出的方法研究西双版纳小果野芭蕉先锋群落优势种群的生态位动态特征。结果表明,该群落中生态位宽度值列前五位的种群是：小果野芭蕉（１．６１５７）,木奶果,榕树,接骨木和苎麻;小果野芭蕉的生态位宽度值随着演替进行逐渐增大;群落中降小果野芭焦与其余物种间生态位重叠值普遍较大外,接骨木,木奶果、苎麻和榕树和它种植物之间具有较大幅度的生态位重叠;在三个演替     

Bioindicator capacity of trees towards dryland salinity

To investigate plant–soil reactions towards site salinity we chose Ruprechtia triflora as the dominant tree species in its natural habitat in dry forests of Paraguay. We applied freezing point osmometry to measure tree leaves and soil samples identically on the basis of colligative solute properties. In order to substantiate the first field findings, the relation of tree and soil in terms of salinity was further investigated under controlled conditions in the greenhouse. R. triflora shows extreme osmotic adaptability. In three independent greenhouse experiments with NaCl application, Ruprechtia seedlings and later Eucalyptus dunnii seedlings from E Australia (for inter-species comparison) showed highly significant responses to their soil salinities. We conclude that tree leaves can serve as bioindicator for soil salinity within the tree’s rhizosphere.     

Small Celastraceae and Polygonaceae twigs from the Upper Cenozoic (Ituzaingó Formation) of the La Plata Basin,Argentina

Two new wood types from the Late Cenozoic of the Ituzaingó Formation, La Plata Basin, Northeast Argentina add to our knowledge of South American Cenozoic plants. The materials were preserved by siliceous cellular permineralization, and they were prepared for microscopic examination by surface polishing and in thin sections. The anatomy of these new species was described. The relationship and comparison with the nearest living relatives (NLRs) are discussed. Maytenoxylon perforatum Franco gen. and sp. nov. is described as the first fossil wood referable to Celastraceae from South America. This new fossil species is related to extant Maytenus Molina. The other fossil twig, Ruprechtioxylon breae Franco sp. nov., has features of the Polygonaceae family and particularly resembles the extant specie Ruprechtia laxiflora Meisn. The occurrence of these fossil woods in south-eastern South America suggests that a relatively warm and dry to seasonally dry climate prevailed over this region of Gondwana during the Upper Cenozoic. It also provides new evidence for the hypothesis of the more wide distribution of Seasonally Dry Tropical Forest (SDTF) during the Upper Cenozoic.     

海南非洲菊根腐病病原的分离与鉴定

从海南省五指山市非洲菊苗圃,儋州市兰花基地非洲菊苗圃的腐烂病根上采集分离到9个疫霉菌株,经鉴定属于隐地疫霉Phytophthoracryptogea。     

A preliminary revision of the supraspecific classification of Kobresia Willd. (Cyperaceae)

Previous supraspecific classifications of the genus Kobresia are evaluated. The evolution of the genus is discussed, and a preliminary revised supraspecific classification based on putative evolution is proposed. Previous classifications were mostly based on inflorescence characters. The spicate inflorescence might have evolved in parallel from a paniculate one, and unisexual spikelet might also be the result of parallel evolution from bisexual spikelets. Therefore, the subgenera or sections Elyna and Hemicarex , which were recognized by previous authors and characterized by the spicate inflorescence (the former with bisexual spikelets and the latter with unisexual ones), may be polyphyletic. In the classification presented here, three subgenera are recognized. A new subgenus Blysmocarex (N. A. Ivanova) S. R. Zhang is proposed. A key to subgenera and sections is included, and types, synonymies and representative species are given under each supraspecific rank.     

盆栽非洲菊基因枪介导法转化体系的建立

以非洲菊盆栽品种为材料,研究了BA和NAA不同浓度组合对不定芽诱导增殖的影响;基因枪介导法转化的不同轰击距离对转化率影响。结果表明：1．5mg／LBA的培养基上增殖倍数最高,高达8．96倍;9cm的目标轰击距离转化效率最高,达到10．9％。建立了非洲菊盆栽品种的再生和转基因体系,为非洲菊基因工程育种打下基础。     

Biological significance of soluble IL-2 receptor

A NUMBER of receptors for growth factors and differentiation antigens have been found to be secreted or released by cells. Following mononuclear cell (MNC) activation and interleukin-2 receptor (IL-2R) expression, a soluble form of the Alpha;-chain of IL-2R (sIL-2R) is released. The sIL-2R has been shown to be present in the culture supernatants of activated MNCs as well as in normal sera and, in higher amounts, in sera from subjects affected by several diseases including neoplastic, infectious and autoimmune ones, and in sera from transplanted patients suffering allograft rejection. The blood sIL-2R levels depend on the number of producing cells and the number of molecules per cell, so that sIL-2R blood values may represent an index of the number and the functional state of producing cells, both normal and neoplastic. Thus, monitoring of the immune system, mostly T-cells and haematological malignancies might be targets for the measurement of sIL-2R. Since many conditions may influence sIL-2R production, little diagnostic use may result from these measurements. However, since blood sIL-2R levels may correlate with disease progression and/or response to therapy, their measurement may be a useful index of activity and extent of disease. The precise biological role of the soluble form of the IL-2R is still a matter of debate. However, we know that increased sIL-2R levels may be observed in association with several immunological abnormalities and that sIL-2R is able to bind IL-2. It is conceivable then that in these conditions the excess sIL-2R released in vivo by activated lymphoid cells or by neoplastic cells may somehow regulate IL-2-dependent processes. On the other hand, it cannot exclude that sIL-2R is a by-product without biological significance. Finally, it is puzzling that in many conditions in which an increase of blood sIL-2R values has been observed, MNCs display a decreased in vitro capacity to produce sIL-2R. These seemingly contrasting findings are discussed in the light of the data showing that sIL-2R production correlates with IL-2 production.     

广东省草本花卉上的拟茎点霉新种和新记录种

报道了采自草本花卉上的一个拟茎点霉Phomopsis新种(千日红拟茎点霉Ph.gomphrenae)和两个中国新记录种(风仙花拟茎点霉Ph.impatientis与埋生拟茎点霉Ph.immersa)。新种千日红拟茎点霉的甲乙型分生孢子不论长度还是宽度均小于之前报道的两个拟茎点霉,并且缺少第三种分生孢子。新种附有拉丁文描述及显微结构图。模式标本保存于华南农业大学真菌标本室(SCHM)。     

四种简易切花保鲜剂比较试验

以瓶插寿命、鲜重及水分平衡值变化为指标,探讨由蔗糖、食盐、酒精、阿司匹林、食醋、青霉素等日常用品组成的四种配方的简易保鲜剂,对香石竹、非洲菊和玫瑰鲜切花的保鲜效果。结果表明,四种保鲜剂中,以配方B(1 L水+10 g蔗糖+10 g食盐+10 ml酒精)保鲜效果较为理想,能改善花枝的吸水状况,延长鲜切花水分平衡时间,从而延长鲜切花瓶插寿命。     

Soluble IL-2 receptor in AIDS. Correlation of its serum level with the classification of HIV-induced diseases and its characterization

By using a fluorescence sandwich ELISA, elevated IL-2R levels were detected in the sera from both HIV-infected hemophiliacs and other HIV-infected patients. The serum IL-2R levels were reflective of the classification of HIV-induced diseases by the Centers for Disease Control. Moreover, the IL-2R levels were negatively correlated most prominently with CD4 cell counts, with lymphocyte counts, and with a decrease in the CD4-CD8 ratio but not with either WBC counts or B cell counts. As striking elevations of serum IL-2R were noted in AIDS patients with group IVD infection, the serum IL-2R was purified sequentially by using size-exclusion HPLC, high-pressure chromatofocusing, and H48 affinity HPLC. The isoelectric point values of IL-2R were separated into 4.2 and 3.8, whereas the Mr was determined to be only 45 kDa by immunoprecipitation with H48 antibody followed by SDS-PAGE. However, production of cellular and supernatant IL-2R was not elevated in PBMC of patients with AIDS or in any of the 19 HIV-I- or HIV-II-infected cell line cells. In contrast, PBMC from patients with adult T cell leukemia and cell line cells that expressed human T cell lymphotropic virus -I or -II produced soluble IL-2R, constitutively. The mechanisms by which serum levels of IL-2R might be elevated in HIV-infected patients are discussed in comparison with that in adult T cell leukemia patients.     

Structural properties of the cAMP-dependent protein kinase associated with rat synaptic plasma membranes--I. Configuration in situ and membrane association-derived influences on [3H]cAMP binding

1. A geometry of molecular ordering in situ characterizes the synaptosomal membrane-bound cAMP kinase, which is revealed from the expression of two equal-size [3H]cAMP-binding domains of differing sensitivity to physical (freeze-thaw) and chemical (reconstitution following salt-effected peripheral protein depletion) treatment of the membrane. 2. Cross-linking of rat synaptosomal membrane proteins with glutaraldehyde revealed after electrophoretic (agarose-polyacrylamide-SDS) resolution and "Western blot" transfer a series of bands with in situ (i.e. on the Western blots) [3H]cAMP-binding capacity. The molecular sizes of these protein bands corresponded closely with those of the cAMP kinase subunit assemblies (R2C2)2, (R2C)2, R2C2, R2C and RC. 3. The subunit assembly (R2C2)2 was also revealed after cross-linking with glutaraldehyde of the purified (commercial preparation) cytosol-derived cAMP kinase II reconstituted in lecithin liposomes. 4. The results support consideration of an operative in vivo configurational shifting between assembly forms and are discussed in the light of the outlined possibility that such shiftings might be involved in the regulation of the membrane-bound cAMP kinase.