Flower Bud Atrophy in Baccara Roses

Changes in gibberellin content and of the production of ethylene in the two upper shoots of roses were measured as affected by decreasing temperature and light intensity, factors which encourage flower atrophy. Decreases in temperature or light intensity to the whole plant reduce the endogenous content of gibberellin in the leaves of the two shoots. The decrease is more rapid and occurs earlier in leaves of the second shoot from the top, where “blindness” is more common. There was also a drop in the gibberellin content, when individual shoots were shaded, although the decrease was more moderate. A lowered light intensity reduced the production of endogenous ethylene by the two shoots, but in the second shoot this production increased after a number of days, before atrophy of the flower bud took place. It is suggested that gibberellin participates in the endogenous control of rose flower development, and the possibility is discussed that it acts by directing the translocation of metabolites to the flower bud.     

Ethylene Induced Flower Opening,Expression of Receptor Genes,and Antioxidant Defensive Responses in Cut Roses

Russian Journal of Plant Physiology - The present research aimed to investigate the effect of ethylene on the physiological and molecular responses of the cut roses, Rosa hybrida L. Two cut rose...     

The Relationship between Sucrose Supply, Sucrose-cleaving Enzymes and Flower Abortion in Pepper

Abortion of pepper flowers depends on the light intensity perceivedby the plant and on the amounts of sucrose taken up by the flower(Aloni B, Karni L, Zaidman Z, Schaffer AA. 1996.Annals of Botany78: 163–168). We hypothesize that changes in the activityof sucrose-cleaving enzymes within the flower ovary might beresponsible for the changes in flower abortion under differentlight conditions. In the present study we report that the activityof sucrose synthase, but not of cytosolic acid invertase, increasesin flowers of pepper plants which were exposed, for 2 d, toincreasing photosynthetically active radiation (PAR) in therange of 85–400 µmol m^-2s^-1at midday. Sucrose synthaseactivity increased in parallel with the increasing concentrationsof starch in the flower ovary. Feeding flower explants, preparedfrom 3-d-predarkened plants, with 100 mM sucrose for 24 h, causeda 23% increase in reducing sugars and a 2.5-fold increase instarch concentration, compared with explants fed with buffer.Likewise, feeding explants of pepper flowers with sucrose, glucose,fructose and also mannitol increased the sucrose synthase activityin the ovaries. Concomitantly, sucrose, glucose and fructose,but not mannitol, reduced the abortion of flower explants. Itis suggested that sucrose entry into the flower increases theflower sink activity by inhibiting abscission and inducing metabolicchanges, thus enhancing flower set. Pepper; Capsicum annuum L.; abscission; light; pepper flowers; sucrose; glucose; fructose; starch; acid invertase; sucrose synthase     

Psychiatric and Social Factors in the Abortion Decision

A total of 132 consecutive referrals for psychiatric opinion on termination of pregnancy were examined and followed up at nine months. Of these, 48 (36%) were refused and 44 of the 84 terminated were sterilized. Those recommended for abortion tended to be older, married, and to have children. They had used contraception more often and they showed more clinical psychiatric abnormalities. The group had numerous social problems, but these did not distinguish those terminated from those refused, nor were there differences in religious affiliation or duration of pregnancy. Most of those refused obtained an abortion elsewhere and only 25 of the original 132 had a live child. General practitioners were more likely to disagree with a refusal decision than with termination. Psychiatric, physical, and social sequelae were infrequent in both groups. Contraception before and after was inadequate in most patients.     

The Relationship between Flower Abortion and Endogenous Auxin Content of Rose Shoots

The amount of endogenous growth substances in stem, flowers and leaves of rose plants grown under different temperature and light conditions has been determined. It appeared to be two main growth promoting factors in the acidic fraction of the ether extract. One of them is assumed to be an auxin, probably indol-3yl-acetic acid (IAA); the other is not identified. The level of auxin was much higher in extracts from shoots grown at high temperature than in shoots grown at low temperature. Increasing light intensity also seemed to increase the auxin content of the shoots. Shoots which developed after a high cut back of the rose stem had a higher auxin content than shoots which developed after a low cut back. These findings are discussed in relation to the effect of temperature, light intensity and cut back practise on blind shoot formation in roses. The result of these investigations strongly indicate that abortion in roses is promoted by a low auxin level in the shoots.     

早期妊娠妇女人工流产的因素调查

目的：了解早期妊娠行人工流产妇女的人群特征,探讨导致妇女人工流产的相关因素,为减少非意愿妊娠提供干预依据。方法：采用整群抽样方法,对丰台区四家二级医院计划生育门诊同期行人工流产的妇女进行问卷调查。结果：共回收调查问卷4381份。调查对象中,平均年龄26岁（16．54岁）,本市户籍占26．8％,外地户籍73．2％;已婚65．33％,未婚34．67％;文化程度初、高中占62．5％;职业列前三位的分别是服务员23．5％、公司职员18．2％、个体工商户10．5％;重复流产为37-3％。非意愿妊娠占83．24％,,非意愿妊娠的原因,39．53％是未避孕,43．71％为避孕失败,而避孕失败的原因中又以避孕套避孕失败居首;意愿妊娠占Ⅲ6．7鹞％,最终选择终止妊娠的原因分别为个人工作因素、情感因素及优生考虑。结论i为降低l妇女非意愿妊娠及重复流产率,对育龄妇女,尤其是流动、未婚人群,需广泛开展性健康教育及避孕方式知情选择,加强避孕知识以及人工流产危害的宣教,指导避孕方法的正确使用,同时,各级医院亟待开展流产后服务。     

Flower Bud Atrophy in Baccara Roses. V. The Effect of Different Growth Substances on Flowering

The effect of various growth regulators on the atrophy of terminal flower buds was tested on Baccara roses. Treatments with gibberellic acid (GA) and 2-chloroethyl trimethyl ammonium chloride (CCC) reduced the atrophy of the flowers. The application of 2-chloroethyl phosphonic acid (CEPA) to the buds enhanced abortion, and the effect was more marked on the lower than on the upper shoot. The stage most sensitive to CEPA was when the shoots were 8–35 cm long. Treatment with abscisic acid (ABA) had no effect of the degree of “blindness”, nor did kinetin applied to the apex affect flowering. Spraying with benzyl adenine increased both the rate of sprouting of the lateral buds and the extent of “blindness” of the sprouting shoots, but did not reduce the number of flowers per branch.     

Factors Affecting Grain Enlargement in Wheat

When most of the grains were removed from wheat ears the remaininggrains developed increased numbers of aleurone and endospermcells, and the increased grain volume was accompanied by anenlarged endosperm cavity. The giant grains usually synthesizedstarch more rapidly than normal grains. Flag leaf photosynthesiswas unaffected and additional sugar was retained in the culmand glumes. Total nitrogen and free amino acid content increased.Gibberellin and auxin concentrations were greater in the glumesof the partly degrained ears, and auxin in the grains was alsogreater than in equivalent grains from intact ears.     

Factors Affecting Transfection in Bacillus stearothermophilus

The conditions for the infection of Bacillus stearothermophilus 4S with TP-1C phage deoxyribonucleic acid (DNA) are described. Cells from log-phase cultures are the most susceptible to phage DNA infection (transfection). A cellular component (competence factor) which enhances transfection is released into the culture medium during the transition period between the log and stationary phase of growth. Transfection is stimulated in the order of decreasing effectiveness, by Fe(3+), Mn(2+), and Mg(2+). The efficiency of transfection is the highest in cells growing at 60.5 C and does not occur in cells growing at 67 C although the cells are growing normally. A cellular component (competence factor) of this organism, which is released into the culture medium, advances by 40 min some step in the uptake of phage DNA.     

Factors Affecting Egg-ratio in Planktonic Rotifers

Edmondson’s egg ratio (number of amictic eggs per female) is an important life history variable, which has been in wide use to understand and predict patterns of population growth in planktonic rotifers under field conditions. It is also useful as an indicator of the health of rotifers under culture conditions. Generally, an inverse relationship exists between the egg ratio and the density of females in a population. A number of abiotic and biotic factors influence the egg ratio. For example, temperature can cause marked changes in the egg ratio by influencing the frequency of egg production and the hatching times of parthenogenetic eggs. Also, preferential feeding on ovigerous females of rotifers by invertebrate predators such as Asplanchna will lower the egg ratios of the population. The easy detachment of eggs, as may be the case in some members of the Brachionidae especially during enhanced reproduction when food levels are high, may also cause an underestimation of the egg ratio. In this review, we discuss the egg ratio of selected rotifer species in relation to the role of diel changes in egg production, the frequency or the intensity of feeding, the problems of distinguishing between different egg types and the negative effect of stressors such as toxicants and diet quality.     

Environmental Factors Controlling Flower Opening and Closing in aPortulacaHybrid

To examine flower opening and closing of aPortulacahybrid, flowerbuds were placed in darkness for 12 h (2030–0830 h) at20 °C and then exposed to various light-temperature conditions.Flower buds exposed to light at 25, 30 or 35 °C opened within1 h, and wilted 10–14 h later. Flower buds exposed tolight at 20 °C started to open after 4 h but opened slowlyand not completely. Flower buds subjected to 25, 30 or 35 °Cin darkness also opened rapidly, but did not reach full opening.Flowers opened at 30 °C in light, and partially closed andopened repeatedly in response to cycles of a 2-h exposure to20 °C and a 2-h exposure to 30 °C at any time between1000 to 1600 h. Similar phenomena were observed when the flowersopened at 30 °C in light and then were subjected to darknessand light alternately at 30 °C, although the effect of lightwas less obvious than that of alternating temperature. Floweropening and closing were not affected by relative humidity.These results indicate that a rise in temperature is requiredfor rapid flower opening in the buds kept at 20 °C, andthat light intensifies the effect of high temperature. Exposureto light without a temperature change delayed and slowed floweropening which was never complete. The involvement of an endogenousrhythm in flower opening byPortulacais indicated. Portulacahybrid, flower opening, flower closing, temperature shift, endogenous rhythm.     

Factors Affecting Chloroplast Replication in Spinach

Chloroplast replication has been studied in discs cut from thebase of young spinach leaves and cultured on sterile nutrientagar. In discs grown in a growth cabinet chloroplast numbersper cell increased logarithmically with time over a 7-day cultureperiod. Chloroplast replication proceeds in a similar way incultured discs and in intact leaves. Cytokinins do not affect chloroplast replication in this systembut they stimulate the fresh-weight growth of discs. Chloroplastreplication is temperature dependent, having an optimum at 25°C. By contrast chloroplast size is at a maximum in discscultured at 12 °C. Light stimulates chloroplast replication, a linear relationshipoccurring between chloroplast number per cell and the dailyquantity of light given to discs up to a saturating value of250 J d^–1. Daylength does not affect chloroplast formationin spinach. In a number of experiments a general relationship was establishedbetween chloroplast number per cell and cell size but no evidenceis available to suggest that this correlation is causal. Theresults of experiments in which discs were transferred fromdark to light suggest that some of the events which precedechloroplast replication may occur at similar rates in both lightand dark.     

Factors Affecting Clonal Diversity and Coexistence

Recent genetic studies of asexually reproducing fishes in thegenus Poeciliopsis (Poeciliidae) revealed abundant variationin the form of multiple sympatric clones. Recurrent hybridizationsbetween sexual species provides the principal source of clonalvariation. The hybrids are spontaneously endowed with a clonalreproductive mechanism that perpetuates a high level of heterozygosity.Migration within and between river systems, and mutations, alsocontribute to clonal diversity in these fish. Coexistence amongdifferent clones and with the sexual ancestors depends in partupon specializations characteristic of individual clones. Clonalreproduction is an efficient mechanism for freezing a portionof the niche-width variation contained in the gene pool of themore broadly adapted, sexual ancestors. Multiclonal populationsachieve significantly higher densities relative to the sexualforms than do monoclonal populations. This relationship is afunction of the clonal variability upon which natural selectioncan act and upon the capacity of a multiclonal population tobetter exploit a heterogeneous environment through niche diversification.In all-female organisms such as Poeciliopsis, which are dependentupon sexual species for insemination, competitive abilitiesprobably are at a premium in the densely populated pools andarroyos of the Sonoran Desert. Competitive abilities are probablyless important for truly parthenogenetic clones which rely oncolonization abilities to escape from their sexual ancestorsand from other clones.     

Factors Affecting Dalapon Absorption and Translocation in Johnsongrass

The factors affecting the absorption and translocation of ¹⁴C-dalapon (2.2-dichloropropionic acid) in johnsongrass were studied. Johnsongrass [Sorghum halepense (L.) Pers.] was first pot-grown in a greenhouse and then treated and placed in controlled-environment chambers. Absorption of ¹⁴C-dalapon into johnsongrass leaves and subsequent translocation occurred continuously within the plant during a 48-h period after treatment. Gas chromatographic analysis of johnsongrass extracts showed that the dalapon molecule was translocated intact. Absorption and translocation of ¹⁴C-dalapon increased as the droplet volume of the diluent was increased from 0.2 to 5.0 μl per treated spot. At 21 and 32°C, translocation of ¹⁴C-dalapon from a 2-cm treated leaf section into the plant was greater at 100% than at 35% relative humidity. At 38°C, translocation was greater at 35% than at 100% relative humidity. The addition of 0.5% surfactant to the dalapon solution increased translocation under all environmental conditions studied. The addition of 0.1 M KH₂PO₄ to dalapon-surfactant solutions increased ⁴-dalapon translocation under high temperature (38°C), especially at 35% relative humidity.     

环境因素对L-异亮氨酸发酵的影响

通过 5L自控发酵罐发酵实验 ,结合发酵过程中菌生长形态的变化 ,对L -异亮氨酸补料分批发酵进行研究 ,研究了环境因素对黄色短杆菌 (Brevibacteriumflavum)TJCN - 1的影响 ,优化出发酵最佳控制条件 ,提出分阶段发酵控制模式 ,对L -异亮氨酸生产有指导意义。     

载脂蛋白A-V对甘油三酯水平影响及其转录的调控

载脂蛋白A-V(apolipoproteinA-V,ApoA-V)是新近发现的载脂蛋白家族中的一员,对血浆甘油三酯水平具有重要的调节作用。ApoA-V的基因表达受到维甲酸相关孤儿受体α、过氧化物酶体增殖物激活受体α、固醇调节元件结合蛋白-1c等因子的调控。该文介绍ApoA-V结构功能方面的研究进展以及它的调控机制;深入研究ApoA-V对全面了解载脂蛋白在脂质代谢中的作用具有重要意义。