A TEN-YEAR RECORD OF ABOVEGROUND BIOMASS IN A KANSAS TALLGRASS PRAIRIE: EFFECTS OF FIRE AND TOPOGRAPHIC POSITION

Measurements of mid-season live and dead aboveground biomass are reported for a 10-yr period (1975–84) in a northeast Kansas tallgrass prairie. Study sites included shallow, rocky upland and deep, non-rocky lowland soils in annually burned (April) and unburned watersheds. Lowland sites had significantly greater live biomass than upland sites for both burned and unburned prairie for the 10-yr period. Moreover, live biomass was greater on burned than unburned lowland sites, but was not significantly increased by fire on the upland sites. Averaged across upland and lowland sites, mid-season live biomass was 422 g m^–2 on annually burned and 364 g m^–2 on unburned sites for the 10-yr period. Each site had its lowest live biomass value during the severe drought year of 1980 (range = 185–299 g m^–2). During the study period, live biomass was most strongly correlated with seasonal pan water evaporation (r = –0.45 to –0.82), whereas dead biomass was correlated with the previous yr's precipitation (r = 0.61 and 0.90 for upland and lowland sites, respectively). When aboveground biomass was sampled throughout the 1984 season and separated into several components, biomass of the graminoids was 40% lower, whereas that of forbs and woody plants was 200–300% greater in the unburned than in the annually burned site.     

金黄色葡萄球菌L型耐药性10年分析

目的 研究金黄色葡萄球菌Ｌ型耐药性变化,确定当前临床用药。方法 对儿科感染性疾病Ｌ型血培养金黄色葡萄球菌进行药敏试验,监测耐药性１０年变化。结果 金黄我葡萄球菌Ｌ型１６９０型,青霉素族,头孢菌素族,大环内酯类,氨基糖甙类及其他抗生素耐药性均升高,丁胺卡那霉素,白霉素,磷霉素,利福平,万古霉素上升幅度较小。结论 金黄色葡萄球菌Ｌ型耐一呈上升趋势,丁胺卡那霉素、白霉素、磷霉素、万古霉素为有效抗生素。     

A CHEMOTAXONOMIC STUDY OF LEMNACEAE

One hundred eighty-six clones of Lemnaceae, representing world-wide collections of 22 taxa, were grown in axenic cultures reproduced by clonal subcultures. Following morphological examinations under a range of culture conditions, a “key” clone was selected to represent each taxon. These key clones were completely representative of the qualitative flavonoid chemistry of the taxa as determined from a number of clones. With the exceptions of Spirodela polyrhiza and S. biperforala which produce identical flavonoids, the flavonoid associations of each species of Lemnaceae were unique in the family. Through paper chromatographic comparisons of purified compounds, plus visible and ultraviolet absorption spectroscopy of isolated individual flavonoids, a total of 47 different compounds was described. These substances included: glycosides of anthocyanidins (cyanidin and petunidin); glycosides of flavonols (kaempferol and quercetin); glycosides of flavones (apigenin and luteolin); and several glycoflavones (C-glycosyl-flavones). When grown under equivalent controlled conditions of culture, infraspecific variation in the qualitative production of these 47 flavonoids was detected in only one flavone glycoside of the species Lemna perpusilla. The reliability of the flavonoid patterns under various conditions of culture was investigated. Under 62 different regimes S. oligorhiza and S. polyrhiza showed only minor variations in their flavonoid glycosides. Studies of other taxa supported this generalization. Under controlled conditions, morphological intergradation obscured identification of many collections. Each could be conclusively identified by its flavonoid chemistry.     

植物气孔扩散传导率的研究(以花生为例)

本文对生长在可控环境温室中的花生气孔扩散传导率进行了实验研究,揭示了单个植株之间、上下表面之间、叶片不同部位以及冠层垂直方向上气孔扩散传导率的变异性。同时以气孔扩散传导率与环境条件的测定值为基础,对传导率对环境因子的反应进行了分析,植株顶部叶片气孔扩散传导率与太阳总辐射和空气饱和差有关系;冠层传导率与冠层截留辐射和空气饱和差有相关关系。     

月经初潮年龄的研究

本文根据西安市及辽宁省开原县2281名女学生及部分青年女农民的调查,得出了西安市女性月经初潮年龄为13.50±1.21岁;开原县则为14.40±1.40岁。月经初潮时间有提前趋势,尤以农村为著。通过不同方法的统计分析,发现寿命表的方法优点较多,现状法调查比较准确。此外,本文还与国内、外的资料做了比较,分析了季节分布特点,探讨了月经初潮的影响因素。     

A FIVE-YEAR STUDY OF PREMATURITY

To get a comprehensive picture of prematurity and neonatal death or survival, all factors on the maternal and fetal records that might be pertinent were recorded. This information, having to do with factors such as age, gravida of the mother, blood group incompatibility, period of gestation, weight at birth, type of delivery, medication and anesthesia administered to the mother, is presented in tabular form.In the study of perinatal mortality it was noted that failure to establish normal pulmonary ventilation is the most common cause of death in the neonatal period. Maternal history of relative infertility, that is, previous abortions, stillbirths and premature deliveries, was the most impressive finding in the stillborn series.In the follow-up study of premature infants who survived the neonatal period, 8.5 per cent were found to be severely handicapped. In four cases the handicap was due to congenital anomalies, in two others probably to infection, leaving 12 with complications possibly ascribable to prematurity. Six of these had retrolental fibroplasia as a major handicap. In seven, mental retardation was the presenting problem. Most of the handicapped children had multiple handicaps, which included spasticity, delayed motor development, strabismus, etc. The incidence of the necessity for corrective measures for feet and legs appeared relatively high.In general, survivors compared favorably with the rest of the childhood population. Complications and twinning were associated inordinately often.     

日本沼虾血细胞的初步研究

甲壳动物血细胞的种类、数量与其免疫功能密切相关。目前,在这个领域中,研究对象主要集中于海水品种［’－’］。本研究以淡水经济虾类——日本沼虾为对象,对上述领域进行初步探讨,以丰富这方面的资料,为今后进一步研究提供参考。材料与方法．l染获试用的染液种类和配方、配法参照文献［8,9］。1．2不同固定剂固定血细胞试验用 lmL注射器（5号针头,下同）先吸取 0．lmL待试验固定剂／ 0．75％生理盐水,再抽取等量血淋巴,混匀后,滴一滴在干净载玻片上,显微镜下观察血细胞形态。l．3血涂片制作选健康日本沼虾【Macrobrachiu。 nm…     

A CYTOGENETIC STUDY OF A THREE-PAIRED RACE OF HAPLOPAPPUS GRACILIS

Haplopappus gracilis (Nutt.) Gray is an aneuploid species of Compositae of wide distribution in the southwestern U.S.A. and northern Mexico. Except for 2 types of supernumeraries, cytological samples from throughout its range have regularly shown 2 pairs of chromosomes. However, recent collections from a small area in south-central Arizona had 2n = 4, 2n = 5, and 2n = 6 in the same population. The 2n = 5 plants were hybrids between the 2n = 4 and 2n = 6 types. Both natural and artificial F₁ hybrids show preferential disjunction from a trivalent and produce genetically balanced gametes with n = 2 and n = 3. In backcrosses of the F₁ to n = 2 plants, a 1:1 ratio of 2n = 4 and 2n = 5 plants was obtained. The possible mechanisms for the evolution of n = 2 from n = 3 and vice versa are discussed.