广西歧舌苔属植物研究及一中国新记录种毛缘歧舌苔

【目的】了解歧舌苔属植物在广西的实际分布情况,为广西苔藓植物研究增加新资料的同时,也为中国苔藓植物多样性保护添加必要的基础数据。【方法】通过近期的野外调查结合广西植物标本馆（IBK）馆藏标本的核查,获得歧舌苔属植物研究材料,经室内形态观察及查阅相关文献,确定其物种多样性。【结果】发现广西歧舌苔属植物标本10份,最终确认广西歧舌苔属植物3种,分别为毛缘歧舌苔,大歧舌苔、阔叶歧舌苔。【结论】歧舌苔科以及岐舌苔属均为首次在广西记录的科属,其中毛缘歧舌苔是中国新记录种。文章对毛缘歧舌苔的形态特征进行了详细描述,对另外2个种主要形态特征进行了归纳,并提供各个种的引证标本信息、地理分布以及彩色图版。     

The ecology of Cenomanian lithistid sponge frameworks, Regensburg area, Germany

Upper Jurassic‐Lower Cretaceous sponge biostromes and bafflestone mounds were common and widespread in European temperate to tropical marine environments. They declined markedly during the Late Cretaceous. Most sponge frameworks were paucispecific and ecologically simple, with only basic levels of succession or tiering. The occurrence of ecologically complex, lithistid sponge biostromes and mounds in the Cenomanian Quadersandstein Member, Regensburger Grünsandstein of the Saal Quarry, Bavaria, is therefore of special significance. These are ecologically the most complex sponge frameworks yet reported from the Cretaceous. Their size, morphology and ecological organization compare favorably with shallow‐water, sponge‐dominated frameworks in modern seas. The Saal Quarry sponge frameworks are generally associated with firmgrounds and condensed intervals in the transgressive systems tract of the Cenomanian‐Turonian, tectonoeustatic supercycle UZA‐2. The lowest sponge frameworks are up to 1 m high bafflestone mounds consisting of large, irregular, sheet‐ and mound‐like recumbent sponges overlain by diverse, cylindrical, pyriform, upward‐branching forms of Jerea and Siphonia. These biostromes overlie a condensed interval or firmground which locally contains small, in situ pyriform sponges (Jerea pyriformis Lamouroux) as well as Middle Cenomanian Inoceramus etheridgei Woods. The upper sponge frameworks consist of bafflestone mounds up to 4.4 m wide and 1.3 m high, composed of six lithistid sponge morphotypes, possibly representing several species of Jerea and Siphonia. The occurrence of Rotalipora cushmanni in strata overlying the upper sponge framework indicates a Late Cenomanian age. Morphotypes preserve internal sponge morphologies and partially dissolved spicules surrounded by a diagenetic halo of silicified, pelletoid grainstone and/or packstone. Silica cements were derived from spicule dissolution. Different combinations of these morphotypes dominate three to four successional stages of sponge framework growth, and show vertical ecological tiering within communities. This ecological zonation is consistent among frameworks, and is partially or wholly repeated between storm‐related disturbance events.     

中国疫霉属真菌异宗配合的种的交配型

明确了异宗配合的疫霉属(Phytophthora)7个种(P.capsici,P.cinnamomi,P.drechsleri,P.melonis,P.nicotianae[=P.parasitica],P.palmivora 和 P.sinensis)47个菌株的交配型。特别有意义的是 P.drechsleri A~1和 A~2两个交配型在南京具有相同的优势,并且证实 P.cinnamomi A~1交配型的存在。     

Hormonal regulation of barley nuclease: investigation using a monoclonal antibody

Abstract. A monoclonal antibody prepared against barley ( Hordeum vulgare L., cv. Himalaya) nuclease (EC 3.1.30.2) was characterized with solid-state enzyme-linked immunosorbent assays and immuno-blotting. The antibody was specific for intracellular and secreted nuclease. Hormonal regulation of the synthesis and secretion of nuclease in isolated aleurone layers was investigated by immunoprecipitation of biosynthetically-labelled nuclease using polyclonal antibodies and by immunoblot analyses using the monoclonal antibody, respectively. Gibberellic acid (GA₃) induced the de novo synthesis and secretion of nuclease in a time-and concentration-dependent manner. Nuclease was detected in aleurone layers incubated in 1 mmol m⁻³ GA₃, after 24 h. The maximum rates of nuclease synthesis and secretion occurred 36–48 h after hormone treatment. A minimum concentration of 10⁻⁶ mol m⁻³ GA₃ was required for nuclease synthesis and secretion, whereas the maximum rate of nuclease secretion occurred at concentrations of 10⁻⁵ mol m⁻³ and higher. In the presence of abscisic acid, the synthesis and secretion of nuclease from GA₃-treated aleurone layers was almost completely inhibited. Based on these findings, the authors conclude that all nuclease within and secreted from aleurone layers treated with GA₃ is the result of its de novo synthesis.     

Investigation of Bidirectional Movement of Tracers in Sieve Tubes of Salix Viminalis L.

Sieve-tube sap was collected as honeydew from the aphid Tuberolachnussalignus (Gmelin) feeding on a young shoot or a mature stemof willow (Salix viminalis L.). Two radioactive tracers (either³H-glucose and ¹⁴C-sucrose, or ¹⁴CO₂, Na₂ ¹⁴CO₃, and ³²P-orthophosphate)were applied to leaves or to bark abrasions at each end of thestem. In some experiments the tracers were applied after thestart of honeydew production, whilst in others the tracers wereapplied before the aphids were sited. In most cases aphids feeding between the tracer applicationpoints produced doubly-labelled honeydew during a 24–48-hperiod from tracer application. In some instances the firstdrops of honeydew contained one tracer, followed several hourslater by the other tracer, whilst some aphids produced doubly-labelledhoneydew from the first drop. Singly-labelled or inactive honeydewwas found in only a few cases. It was demonstrated that when ³H-glucose and ¹⁴C-sucrose wereapplied at opposite ends of a stem that the tracers moved inopposite directions in the form of sucrose. The data suggest that a simultaneous bidirectional movementof two tracers may occur in the same sieve tube. However, thepossibility that the doubly-labelled honeydew could be producedby lateral movement from one sieve tube carrying one tracerto an adjacent punctured sieve tube carrying the other tracercannot be discounted.     

An Effect of Ethylene on the Distribution of 14C-sucrose from the Petals to Other Flower Parts in the Senescent Cut Inflorescence of Dianthus caryophyllus

The distribution of carbon-14 in the flower parts of the cutcarnation inflorescence after feeding ¹⁴C-sucrose through thepetals was studied during natural ageing and after ethylenetreatment. Levels of ethylene which caused irreversible wiltingof petals also promoted an accelerated transfer of the radioactivesucrose to the nectar, gynaecium and stem. Since the nectarreceived a relatively large proportion of the radioactive carbon,the composition of the sugars in the nectar and the vascularizationof the nectary were investigated. Sucrose comprised about 85per cent of the nectar sugars and the balance was glucose andfructose. The vascular tissue closest to the nectary consistedof phloem elements; tracheary elements terminated deeper inthe receptacle and were surrounded by a ring of phloem. Thepercentage of solutes in the nectar was about 18 per cent andincreased when the flowering stems were placed in sucrose solutions;the solutes in the nectar were principally sugars. Taken togetherthe results show that the nectary can act as a sink for sucroseand, in the flower at least, that translocation of sucrose takesplace in the phloem. The results provide further evidence forthe hypothesis that ethylene promotes mobilization of substrateand an efflux of material from petals to the gynaecium, nectarand stem.