用气象因子组建一代粘虫发生区越冬代蛾量及迁入期的长期预测模式初探

粘虫(Mythimna separata Walker)是我国粮食作物的重要害虫。我国江淮及黄淮流域是一代粘虫发生区,粘虫全年发生四(或五)个世代,以第一代发生数量最多,春季4、5月间为害小麦。该区在根治我国粘虫危害上具有战略地位。决定一代粘虫发生程度的主导因素,是越冬代蛾量迁入的多少。因此组建该区越冬代蛾最及迁入期的预测模式,有着特别重要的现实意义。 目前在国内,关于粘虫发生期和发生量预测,多属中、短期,且以短期预测为主。据研     

THE DISTRIBUTION OF CELL GENERATION TIMES

Two different distributions of generation times, log-normal and reciprocal normal, were compared by fitting them to experimental generation time distributions for bacteria, yeast, protozoa, and mammalian cells. In every case, the reciprocal normal distribution gave better agreement, whether the original frequency distributions or their cumulatives were compared. the log-normal distribution failed to give significant agreement for three of the original distributions. It is concluded that the reciprocal normal distribution of generation times, or more precisely, the truncated normal distribution of generation rates, is consistent with the published data for steady state populations of all kinds of cells that divide by regular binary fission. A model is suggested for this distribution of generation times, associating it with control of transport of materials into the cell, and with linear cell growth.     

VISUAL CHARACTERIZATION OF THE ESTHETIC QUALITY OF THE ROSEBUSH

Since its introduction into the analysis of foodstuffs, sensory analysis has been applied in several contexts. This work seeks to widen the field of sensory analysis to include ornamental plants and to characterize their esthetic quality. Using the rosebush as a plant model, an attribute generation protocol is proposed in order to develop a conventional profile of such products. Further to statistical treatments aiming to verify the unambiguity, discrimination and independence of these attributes, a reduced list of 18 attributes has been set up. These attributes make up the very core of the conventional profiling studies currently undertaken .

PRACTICAL APPLICATIONS

The generation of a list of attributes that is not too long, in order to describe plants as exhaustively as possible, is one of the first steps of extending sensory analysis methods to ornamental horticulture. This list will be used to train a panel of assessors to characterize the rosebush.
Two applications are in progress. The first application consists of evaluating the impact of nitrogen nutrition on the visual quality of the rosebush. The second has the objective of determining which characteristics influence consumer preferences.     

THE REGULATION OF ALTERNATION OF GENERATION IN FLOWERING PLANTS

The developmental changes involved in the alternation of generation represent the major gene-switching events in the life history of plants. While a large number of genes are common to both sporophyte and gametophyte, many thousand sequences are specifically expressed in each generation; indeed, certain key constituents (e.g. tubulin) are encoded by different genes in each generation, indicating that sporophyte and gametophyte are responding to different evolutionary pressures. Evidence is accumulating that major gene-switching events in plants, such as flowering, are regulated by complex control systems which ensures that development occurs only in the correct groups of cells at the appropriate time. A similar, or more sophisticated system might thus be expected to regulate alternation of generation. It is not possible to manipulate alternation of generation in a similar fashion to flowering, but study of apparent aberrations of development occurring in nature and in vitro suggests that alternation only occurs in cells which have become competent to receive particular developmental stimuli. Further, in certain cases, competent cells may be switched either into sporophytic or gametophytic developmental pathways depending upon the nature of the stimulus. Acquisition of competence seems to involve isolation of cells from the symplast, some cytoplasmic dedifferentiation, and perhaps cell cycle arrest or transition. The stimuli in vivo appear metabolic in nature, although embryogenesis may be activated by specific classes of glycoproteins. Interestingly, examination of agamospermic systems suggests that fertilization of the egg per se is not the signal which activates sporophytic development. Once competent cells have received the stimulus they start to develop, with no delay in a ‘determined’ state. Sporophytic and gametophytic development in vivo and in vitro both start with an asymmetric division, except for the female gametophyte which may arise via a range of developmental pathways, depending on the species.     

THE EFFECT OF THYMIDINE ON THE DURATION OF G1 IN CHINESE HAMSTER CELLS

The generation time of a Chinese hamster cell line was varied by the use of different lots of sera in the culture media. Analysis of the division waves following thymidine synchronization showed that lengthening of the generation time was a result of an increase in duration of the G₁ phase and that thymidine treatment reduced the duration of G₁ back to its minimum value.     

INTRAPOPULATION KINETICS OF THE MITOTIC CYCLE

Data obtained with time lapse cinemicrographic techniques showed that the distribution of generation times for exponentially proliferating human amnion cells in culture is skewed to the right and that reciprocals of generation times appear normally distributed. As shown for bacteria, the true age distribution is much broader than theoretical distributions which fail to take into account the dispersion of generation times. By means of the technique utilizing autoradiographic detection of tritiated thymidine in cells whose mitotic histories were recorded by time lapse cinemicrography, it was shown that the G1 distribution is similar to the generation time distribution but is more variable. In our experiments, the G2 + prophase distribution resembled the generation time and G1 distributions. The data suggested two possibilities for S: either it is relatively constant, or it is inversely related to the lengths of G1 and G2 + prophase. Since G1 is more variable than the total cycle, and G2 + prophase more variable than the computed sum of S + G2 + prophase + metaphase, it was concluded that the relationships between parts of the cycle are non-random and that compensating mechanisms apparently help regulate the lengths of successive parts of the mitotic cycle in individual cells.     

鲤鱼杂种优势多代利用的探讨

作者根据自己的工作和当前国内外有关研究工作的进展情况,提出了通过人工诱发杂种三倍体,并用雌核发育的方式繁衍后代的途径,以防止鲤鱼品种间杂交后代分离,从而达到杂种优势多代利用的设想。       

粘虫的迁飞发生区及其分布的数学模型

粘虫(Mythimna separata Walker)的年周期远距离迁飞,早已为我国多数昆虫学者所证实(林昌善等、1963、1964;马世骏;1963;陈永林等,1963;李光博等,1964;陈瑞鹿等;1965;李绵春等,1965)。作者亦曾于1962年全国昆虫学会及1963年广东省植保学会上提出数据,同意此观点。并作出全国粘虫迁飞发生区地图,综合粘虫的水平迁飞及垂直迁飞为害实况,绘出福建南部,广东中、南部,广西中、南部,云南南部为第一次发生区,2—3月幼虫为害小麦。山东南部,河南中、南部,陕西东、南角西至贵州、四川、云南的平坝地     

褐飞虱致害性变异过程及其体内酶的变化

在室内连续用具不同抗虫基因的水稻品种TNl、IR26、Mudg。和ASD7、单管饲养褐飞虱(Nilaparvata lugens)种群,研究它对抗虫水稻品种的适应过程及其体内酶的变化规律。 结果表明：褐飞虱在抗虫品种上取食2代的若虫存活率、若虫历期和短翅成虫体重均明显比取食感虫品种TNl的低,第3代以后与取食TNl者基本相同。第2代是褐飞虱适应抗虫品种的关键期。天冬氨酸氨基转移酶(AST)、丙氨酸氨基转移酶(ALT)和丁-谷氨酰基转移 酶(GGT)的活性在关键的第2代最低,而超氧物歧化酶(SOD)和过氧化氢酶(CAT)的含量增加。褐飞虱在适应抗虫品种以后体内天冬氨酸氨基转移酶活性明显提高。     

天敌对马尾松毛虫自然种群的影响

马尾松毛虫 Dendrolimus punctatus Wlaker分布于我国南方十三个省,是毁害森林的大害虫。近年来每年发生虫害面积达3000—4000万亩,损失木材达500—700余万立方米。在广西为害也极严重。广西钦州县红卫林场有4万亩马尾松纯林,营造于六十年代中期,是广西马尾松毛虫为害的常灾区、重灾区。马尾松毛虫在该林场每年发生三     

THE EVOLUTION OF FITNESS

In every generation, the mean fitness of populations increases because of natural selection and decreases because of mutations and changes in the environment. The magnitudes of these effects can be measured in two ways: either directly, by comparing the fitnesses of selected and unselected populations, or indirectly, by measuring the additive variance of fitness and making use of the fundamental theorem of natural selection. The available data suggest that the amount by which natural selection increases mean fitness each generation (or degradation decreases mean fitness) will usually be between 0.1% and 30%; more tentatively, it is suggested that values will typically fall between 1% and 10%. These values can be used to set an upper limit of 5%–10% on the genetic advantage of mate choice.     

棉红铃虫自然种群的生命统计特征

1978-1988年,在湖北省江汉平原棉区,用编制特定年龄生命表的方法,研究棉红铃虫Pectin ophora gossypiella(Saunders),第1至3代的自然种群生命统计特征值。 世代存活率(占)为3.23,4.01和1.46;各虫态发育阶段(X)与相应阶段存活率的关系为：y₁=61.66e-0.58s、Y₂= 142.47e^-0.73s、 y₃=146.68e^-0.80s种群鹃势指数(I)：1.12、2.03和0.45;每雌蛾平均及最高产卵量：35(253)、51(235)、31(293)粒;自然内禀增长率(r')为0.0390、0.0403和0.0026;净增殖率?：4.39、4.43和2.04;周限增长率(兄)：1.0398、1.0411和1.0026;世代长度(T)：38、37和276日;种群加倍时间(t)18、l7和26,天。上列十个生命统计值已成为组建棉红铃虫的计算机辅助决策模型所必须的基质。 第二代是全年的关键世代,各代钻蛀期的幼虫数及越冬期的幼虫数是影响下一世代或次年种群数量的关键虫态,钻蛀期幼虫的自然死亡是致死的主导因子。     

AUTORADIOGRAPHIC INVESTIGATION ON THE CELL KINETICS OF CRYPT EPITHELIA IN THE JEJUNUM OF THE MOUSE °CONFIRMATION OF STEADY STATE GROWTH WITH CONSTANT FREQUENCY DISTRIBUTION OF CELLS THROUGHOUT THE CYCLE

Cell kinetic parameters of cells in the crypt of the jejunum of the mouse were obtained autoradiographically. A number of different methods used in cell proliferation studies were applied to the same animal strain kept under constant conditions. In order to avoid effects of geometrical factors, squashes of isolated crypts were used.
The generation time was determined by the per cent labelled mitoses method of Quastler, modified by double labelling with ³H- and ¹⁴C-TdR. This modified method permits a more exact determination of the generation time. The duration of the cycle was 14 hr.
Double labelling experiments in which an injection of ³H-TdR was followed by an injection of ¹⁴C-TdR after 1 hr showed that the cell flux was 7.0%/hr at the beginning of the S-phase and 7.68%/hr at the end. Assuming steady state growth a constant cell flux of 7.15%/hr within the whole cycle can be derived from the measured generation time of 14 hr. These results clearly show that the crypt epithelia constitute a steady state system with constant frequency distribution of the cells throughout the cycle.
The per cent labelled mitoses method after a single injection of ³H-TdR as well as double labelling experiments with ³H- and ¹⁴C-TdR give an estimate of the S-phase of 8.0 or 7.4 hr respectively. Double determinations lead to a value of 0.54 or 0.52 hr respectively for the duration of mitosis and to values of 77% and 72%     

棉田亚洲玉米螟生物学的研究

亚洲玉米螟为棉花上一种重要的钻蛀性害虫。该虫产卵于棉抹中下部主茎叶和果技叶上,但二、三代代次之间产卵部位有明显差抖。幼虫可为害棉株的嫩头、叶柄、蕾、花、铃、茎秆等多个器官,棉花同-器官上各龄幼虫之间的分布、以及同龄幼虫在棉花不同器官之间的分市．均存在显差异。1头幼虫一生破坏棉花器官的单位效二代为3.373个．三代为2.202个。二年的试验结果表明,田间二代亚洲玉米螟种群趋势指数差异大。三代幼虫越冬场所广泛。     

THE EFFECTS OF SPRAY TREATMENTS ON INFESTATION OF THE OAT CROP BY THE FRIT FLY (OSCINELLA FRIT L.)

Criteria are given for the timing and assessment of the effect of sprays on experimental plots, based on biological observations at Silwood Park from 1950 to 1955 and on previous work.
A preliminary experiment on small plots in 1952 indicated that 'blanket spraying' with DDT and parathion throughout the life of the crop gave protection against both tiller and grain attack. A more detailed replicated plot trial in 1953 showed that for oats planted on 22 April two carefully timed tiller sprays with parathion reduced tiller infestation from 31 to 3%. Six panicle sprays at weekly intervals reduced a heavy grain attack of 60% to 13%. Dieldrin was also effective but significantly less so than parathion. Much of the damage to the crop was caused by weed growth following initial loss of the primary oat shoots.
In 1954 and 1955 two and three parathion sprays were applied to 2-acre fields in order to study recolonization. Despite almost complete control of the tiller generation, a normal evenly distributed infestation of the panicles was found.
It is concluded that good control of the tiller generation may best be achieved by a spray programme based on knowledge of the phenology of the fly combined with that of the crop. The first general emergence in early May is likely to be critical.
Reinvasion of a sprayed crop may take place within 4–5 days and panicle infestation may not be causally related to tiller infestation in the same field.     

小麦异细胞质效应的研究

采用四种异细胞质“中国春”小麦即（Ｔ．ＺｈｕｋｏｖｓｋｉＧ）ｃｓ,（ＡｅＭｕｔｉｃａＭ）ｃｓ（Ａｅ．ＶａｒｉａｂｉｌｌｉｓＳ）ｃｓ（Ａｅ．ＣｒａｓｓａＤ＾２）ｃｓ与普通小麦“哈师一号”杂交,探讨异细胞质的效应。结果表明：不同细胞质对杂交当代的结实率,种子饱满度,发芽率,Ｆ１的株高,分蘖数,穗长,生育期,育性的不同的影响,特别是育性差异较大,Ｆ１的减数分裂行为：在Ｇ型,Ｍ＾ｔ型细胞质Ｆ１植株中出现少     

THE DEVELOPMENT AND CYTOLOGY OF THE EPIBIOTIC PHASE OF PHYSODERMA PULPOSUM

Lingappa , Yamuna . (U. Michigan, Ann Arbor.) The development and cytology of the epibiotic phase of Physoderma pulposum. Amer. Jour. Bot. 46(3) : 145-150. Illus. 1959.—Physoderma pulposum, a chytrid parasite on Chenopodium album L. and Atriplex patula L., has a zoosporangial epibiotic phase. The latter consists of extramatrical sporangia and intramatrical bushy rhizoids, both enclosed in large protruding galls. The sporangia are subspherical, up to 350μ in diameter, and may produce hundreds of planospores. If planospores settle on the host surface, they develop narrow germ tubes which penetrate the epidermal cells and develop into rhizoids. The planospore body, however, remains on the host surface and develops into a mature epibiotic sporangium in about 20-25 days at 16°C., 12-15 days at 20-25°C., or 6-8 days at 30°C. During development, its nucleus and daughter nuclei divide mitotically with intranuclear spindles until the sporangium contains several hundred nuclei. This is followed by progressive cleavage which delimits the planospore rudiments. When mature sporangia are placed in fresh water, the planospores are quickly formed within 1 hr. at 25°C. and begin to swarm within the sporangia. They escape in large numbers through an opening formed by the deliquescence of a papillum in the sporangial wall. The planospores are subspherical or elongate, 3-5 × 4-6 μ, and each has an eccentric orange-yellow refractive globule and a flagellum 18-22 μ in length. The electron micrographs of the flagella indicate that the flagella are absorbed from tip backward during encystment of the planospores. By periodic inoculation of the host plants with planospores from epibiotic sporangia, as well as from germinating resting sporangia, generation after generation of epibiotic sporangia have been obtained for 4 years. This proves the existence of a eucarpic, epibiotic, ephemeral zoosporangial phase in P. pulposum. Field observations on the duration and sequence of development of the fungus indicate that the endobiotic resting sporangial phase always follows the epibiotic phase. The results of infection experiments also indicate that the epi- and endobiotic phases belong to one and the same fungus, P. pulposum.     

FOLLOWING THE THREAD TO OAK SPRING: THE AFTERLIFE OF JOHN BRADBY BLAKE'S CANTON DRAWINGS

For more than 175 years, the remarkable botanical drawings made in Canton by a Chinese artist working with the British East India Company supercargo John Bradby Blake, were handed down from generation to generation within the same family. They first appeared publicly in 1959 when the estate of Sir Frederick Cripps of Ampney Park, Gloucestershire, came up for auction. A Bristol art dealer bought the drawings, but on the other side of the Atlantic, Paul Mellon had other ideas for them. This article follows the trail from London, via Ampney Park and Bristol, to Oak Spring, Virginia.     

鲤咽齿个体发生及其与近缘种间关系的比较研究

鲤具鲤科咽齿个体发生的共同性征,又呈现其种的独特性状.主要特性;(1)主列齿相连3齿胚几乎同时出现、同时脱落,形成3个相连齿种同时置换的特殊模式;(2)主列齿发生中曾出现4枚齿,替换3代后A_4齿退化消失,最终齿式1.1.3-3.1.1,成为迄今3列咽齿的鱼类中齿数最少的种类.鲤与其近缘种间系统关系比较结果;依最近缘属顺次排列为中鲤、原鲤、肥鲤;而最近缘的亚科为肥亚科.       

CLONE SIZE ANALYSIS: A PARAMETER IN THE STUDY OF CELL POPULATION KINETICS

The method of clone size analysis is described. Such an analysis provides a measure of the distribution of generation times in a cell population. Treatment by ionizing irradiation leads to perturbation of the generation times of a cell population and such perturbations are shown by changes in the clone size distribution. Distributions were compared after neutron irradiation and β-irradiation with those after X-rays; and also between X-irradiation under aerobic and anoxic conditions. At the same level of cell survival no differences were found between the patterns of cell survival with respect to generation times. Other uses of clone size analysis are discussed.