黄土高原油松林地产流产沙及其过程研究

通过对径流小区的多年观测和人工模拟降雨试验,利用自制的径流自动记录装置,研究了油松林地不同处理的产流产沙及其动态过程。研究结果表明,油松林地、林地去枯枝落叶层和采伐林地上层林木等３种处理与农地比较,分别减少径流量８８．０％、２７．０％和８７．８％,减少产沙量９９．９％、９８．０％和９９．８％。产沙量与坡度和雨强关系密切,随坡度和雨强增加而迅速增加,以雨强的效应更甚。油松林地开始产流的降雨量一般在１     

PRODUCTION AND ROLE OF INTERFERON IN PHYSIOLOGICAL CONDITIONS

1. There is convincing evidence that a number of agents such as bacteria, viruses, endotoxins, foreign proteins, smokes and chemicals come into contact under physiological conditions with the lymphoid tissue associated with the gut and/or bronchial systems. Endogenous lectins and proteases may also act as mitogens on the central and peripheral immune system. 2. It is suggested that these agents act as inducers of interferon (and some also as immunogens), so that local production of interferon is turned on successively from cell to cell depending upon their responsiveness and upon the periodic inflow of inducers. 3. On the basis of a number of different features, it is proposed to distinguish between an ‘acute’ and a ‘physiological’ interferon response. In the latter, the interferon-producing cell influences the neighbouring cells by short-range humoral transmission (paracrine control) and possibly by cellular interaction, while the route of the general circulation is preferentially used in the former response. 4. It is suggested that the physiological interferon response, although previously overlooked, has great biological importance because production of interferon at strategic sites can maintain active defence systems essential for survival. 5. It is to be expected that the physiological interferon response, although amenable to experimental verification, may be difficult to detect. On the basis that interferon is normally absent from serum, it is suggested that most of the released immune-type interferon is either bound by cells surrounding the site of its synthesis or catabolized locally. 6. It is postulated that the progressive decline of the physiological interferon response with increasing age may represent one of the factors favouring the insurgence of autoimmune diseases and tumours in the process of ageing. It is also suggested that the involution of the thymus may in part be due to intrathymic production of interferon induced by proteases released from macrophages.     

FERMENTATIVE AND PHOTOCHEMICAL PRODUCTION OF HYDROGEN IN ALGAE

1.. After 2 hours of fermentation in nitrogen the metabolism of those algae which were found capable of photoreduction with hydrogen changes in such a way that molecular hydrogen is released from the cell in addition to carbon dioxide. 2. The amount of hydrogen formed anaerobically in the dark depends on the amount of some unknown reserve substance in the cell. More hydrogen is formed in presence of added glucose, but no proportionality has been found between the amount of substrate added and that of hydrogen formed. This is probably due to the fact that two types of fermentation reactions exist, with little or no connection between them. Whereas mainly unknown organic acids are formed during the autofermentation, the addition of glucose causes a considerable increase in the production of lactic acid. 3. Algae which have been fermenting for several hours in the dark produce upon illumination free hydrogen at several times the rate observed in the dark, provided carbon dioxide is absent. 4. Certain concentrations of dinitrophenol strongly inhibit the evolution of hydrogen in the dark. Fermentation then continues mainly as a reaction leading to lactic acid. In such poisoned algae the photochemical liberation of hydrogen still continues. 5. If the algae are poisoned with dinitrophenol the presence of carbon dioxide will not interfere with the photochemical evolution of hydrogen. 6. The amount of hydrogen released in this new photochemical reaction depends on the presence of an unknown hydrogen donor in the cell; it can be increased by the addition of glucose but not in proportion to the amount added. 7. The results obtained allow for a more correct explanation of the anaerobic induction period previously described for Scenedesmus and similar algae. The possibility of a photochemical evolution of hydrogen had not been taken into account in the earlier experiments. 8. The origin of the hydrogen released under the influence of light is discussed.     

水稻铁害和应激乙烯释放的关系

在热带地区的水稻栽培中,常遇到水稻青铜病（ｂｒｏｎｚｉｎｇ）的危害．已知它是由水田中高浓度的亚铁离子所引起,故又叫铁害．但至今没有可靠的生理诊断指标用于抗性品种的筛选．本文研究了铁害与应激乙烯释放的关系,试图以应激乙烯的释放作为铁害的生理诊断指标．试验用两种方法模拟水稻致病．第一种方法是将水稻离体叶片的剪口端浸入ＦｅＳＯ４溶液中,靠叶片蒸腾作用吸收Ｆｅ＋＋而致病．另一种方法是在水培培养液中加入ＦｅＳＯ４通过水稻根系吸收Ｆｅ＋＋而致病．研究结果表明,当处理离体叶片时,发病强度和应激乙烯释放量呈显著相关,但叶片内铁含量的增加与发病强度和应激乙烯释放都没有相关性．而处理完全植株时,叶片中乙烯释放几乎不受影响．当部分或全部切除根时,叶片中乙烯释放则可被亚铁离子激发。表明水稻根系限制了Ｆｅ＋＋的吸收速率,而Ｆｅ＋＋进入叶组织的速率又决定应激乙烯的释放和组织的伤害程度．因此,叶片应激乙烯的释放作为铁害的生理诊断指标只有在当根系受到某种伤害时才可能适用,譬如移栽和毒性土壤等因素造成的根系的伤害．     

CAULINE VASCULATURE AND LEAF TRACE PRODUCTION IN MEDULLOSAN PTERIDOSPERMS

Medullosa and Sutcliffia specimens from the Paleozoic of North America and Europe are examined to determine the architecture of the cauline vasculature and mode of leaf trace production. Emphasis is placed on the identification and characterization of protoxylem strands and their relationship to leaf trace production. Organization of the primary xylem varies from a single protostele to a dissected stele composed of two to many more or less independent bundles. In Medullosa the bundles of primary xylem are each surrounded by secondary xylem, forming separate segments of vascular tissue (‘steles’ of previous workers). These vascular segments may divide and fuse at different levels in the stem. A definite number of protoxylem strands occur near the periphery of the primary xylem. The protoxylem strands divide at intervals producing protoxylem to the departing leaf traces. Leaf traces thus formed arise from all the vascular segments in a coordinated and predictable way and pass outward through emission areas in the secondary xylem. This type of cauline vascular architecture is compared to that of other seed plants. The vascular system of Medullosa stems is interpreted as a dissected monostele. Sympodial vascular architecture has apparently evolved from a protostele separately within the medullosan pteridosperms.     

我国森林植被的生物量和净生产量

利用森林蓄积量推算森林生物量和净生产量的方法,系统研究了我国森林植被的生物生产力。结果表明,我国森林生物生产力的地理分布规律与世界总趋势一致,但量上有差异,具体表现在：我国森林生物量的平均值小于世界平均水平,而净生产量却显得较高;我国森林的总生物量是９１０２．８７×１０６ｔ,其中,林分为８５９２．１３×１０６ｔ,经济林３２５．７２×１０６ｔ;竹林１８５．０２×１０６ｔ,疏林、灌木林７９０．５４×１０６ｔ;森林和疏林（含灌木林）的总生产力分别是１１７７．３１×１０６ｔ／ａ和４５８．１６×１０６ｔ／ａ。研究结果还显示,用材积推算的生物量（材积源生物量）比用平均生物量计算的结果更符合实际。分析中国森林在中国及全球陆地碳库中的作用发现,与其他区域和世界平均水平相比较,中国森林在中国陆地植被中所起的主导作用较弱,它的生物量不足全球森林总生物量的１％,然而,它在保护中国土壤碳库功能方面起着其他植被类型所无法替代的作用。     

CATKIN FREEZING AND ACORN PRODUCTION IN GAMBEL OAK IN UTAH, 1978

In May 1978, a general freeze of the male flowers of Gambel oak (Quercus gambelii Nutt.) was observed in northern Utah. In August, transect reconnaissance was conducted throughout Utah to assess acorn production and the incidence of freeze damage in Gambel oak. It was found that below ca. 1950 m elevation acorn production was relatively low while the incidence of freeze damage was high. Above ca. 1950 m elevation, where the oaks were still dormant at the time of the freeze, acorn production was relatively high while freeze damage was relatively low. Occasional acorn production observed at low elevations appeared to be associated with subterranean pooling of water and/or cold air drainage. Some biogeographic implications of freeze stress are discussed.     

我国薯芋皂甙元的工业生产和资源的回顾与展望

本文对我国薯芋皂素(Diosgenin)的工业生产进行了概略回顾,对各种工艺流程进行了比较,并介绍了薯芋属植物的资源现状。     

GENDER VARIATION AND SEXUAL DIFFERENCES IN REPRODUCTIVE CHARACTERS AND SEED PRODUCTION IN GYNODIOECIOUS GERANIUM MACULATUM

Variation in sex expression, flowering pattern, and seed production was studied in the self-compatible perennial herb Geranium maculatum in Illinois and Indiana. In a survey of eight populations, female (male-sterile) plants were found in seven (frequencies ranging from 0.5% to 24.3% [median 4.2%]), and intermediate plants (with partly reduced male function) were found in all populations. Gender variation and sexual differences in reproductive characters were studied in detail in two populations. One population consisted of 5% female, 27% intermediate, and 68% hermaphrodite plants; the other consisted of 1% female, 20% intermediate, and 79% hermaphrodite plants. Females produced smaller flowers and began flowering earlier than hermaphrodites. Intermediates produced flowers of an intermediate size and began flowering as early as females. Females and hermaphrodites did not differ in flower number, vegetative size, flowering frequency, survival, or seed size. However, females produced 1.6 times more seeds than hermaphrodites. Intermediates produced 1.3–1.6 times more seeds than hermaphrodites. Some between-year variation in sex expression was observed. Hand-pollination with outcross pollen produced two to four times as many seeds as hand-pollination with self-pollen. A lower outcrossing rate in hermaphrodites than in females may at least partly explain the lower seed set in hermaphrodites. The higher seed production of females, and possibly the high fecundity of the intermediates, should contribute to the maintenance of this sexual polymorphism.     

CELL PRODUCTION IN TUMOUR ISOGRAFTS MEASURED USING VINCRISTINE AND COLCEMID

Vincristine sulphate has been found to be a more useful metaphase arrest agent than Colcemid. Metaphase accumulation, in isografts of a CBA mammary adenocarcinoma, was linear with time for at least 10 hr after vincristine administration and also independent of drug dose in the range 1–4 mg/kg body weight. A method for evaluating the cell production rate, in histological sections, of a cell population which forms a heterogeneous component of the tissue has been described. The percentage of each tissue component was determined using the Chalkley point count method and the mean number of metaphases in an arbitrary defined field were evaluated. Corrections for percentage composition and sectioning were applied and the cell production rate defined. This was found to be 15.8 ± 0.6 cells per 1000 cells per hour for this tumour.     

影响活体内马铃薯晚疫病菌卵孢子产生因素的研究*

研究了不同菌株组合,马铃薯植株茎、叶及接种物中A1和A2菌株孢子囊比例、温度、湿度对卵孢子产生的影响。不同菌株组合产生卵孢子的数量有显著差异;在离体接种情况下,叶片中产生卵孢子数量大于茎中产生卵孢子数量;A1和A2菌株中孢子囊不同比例对卵孢子产生影响很大,当比值为1∶1时卵孢子产生量最大;15℃光照条件下培养,并给侵染叶片持续的水分供应才能产生大量卵孢子;寄主的抗性水平对卵孢子产生有明显的影响,中抗品种上产生卵孢子量最多,高抗品种上产生卵孢子量最少,感病品种上产生卵孢子量居中。