水稻苗期磷高效基因型筛选研究

采用难溶性磷酸盐Ca3 (PO4) 2 为唯一磷源 ,在pH值为 5 .5条件下产生相对高浓度低磷胁迫及以NaH2 PO4为磷源配制P浓度为 0 .5mg·L-1的相对低浓度低磷胁迫的两个水培环境 ,分别对不同基因型水稻的磷效率进行评价 .以相对分蘖干重 (RTW )、相对总生物量 (RPW )、相对分蘖数 (RTN)、相对根系干重(RRW )、相对地上部干重 (RSW )、相对叶龄 (RLA)和相对株高 (RPH)作为耐性指标进行相关分析 .结果表明 ,供试材料的磷效率存在极显著差异 ,若以能产生分蘖的相对高浓度低磷胁迫进行筛选时 ,相对分蘖干重、相对地上部干重、相对总生物量可作为较好的筛选指标 ,其中相对分蘖干重不仅与其它指标间的相关性强 ,且品种间差异和变异系数均较大 ,能准确、灵敏地反映不同基因型间的耐低磷胁迫能力 ;若采用相对低浓度的低磷胁迫对不同基因型水稻进行耐低磷种质筛选时 ,筛选指标则不同 ,最好的单一筛选指标应是相对地上部干重或相对总生物量 .     

Do Young Children Understand Relative Value Comparisons?

Many forms of judgments, such as those used in economic games or measures of social comparison, require understanding relative value, as well as the more complex ability to make comparisons between relative values. To examine whether young children can accurately compare relative values, we presented children 4 to 7 years with simple judgments of relative value in two scenarios. Children then were asked to compare the relative values in the two scenarios. Results show that even the youngest children downgraded evaluations of a reward when another has a larger amount, indicating the ability to make relative value judgments. When asked to compare relative values however, only the oldest children were able to make these comparisons consistently. We then extended this analysis to economic game performance. Specifically, previous results using economic games suggest that younger children are more generous than older ones. We replicate this result, and then show that a simple change in procedure, based on the initial study, is sufficient to change young children’s choices. Our results strongly suggest that conclusions regarding young children’s pro-social motives based on relative value comparisons should be viewed cautiously.     

The relationship between the relative growth rates of the shoot system, number of tillers and mean tiller size in Lolium perenne

The relative growth rate of the shoot system of Lolium perenne may be considered as being made up of two components, the relative growth rate of the increase in the number of tillers and the relative growth rate of the mean tiller. These three relative growth rates were calculated for twenty-two clones of Lolium perenne growing in twenty-eight environments. Analyses of variance showed that differences in the environment were responsible for a greater amount of variation than either differences between clones or the interaction between clonal and environmental influences.
For each clone it was possible to calculate relationships between the relative growth rate of the shoot and its two components as they varied with the environments. The relationships held irrespective of the environmental factor(s) which altered to cause the difference in relative growth rates. In all clones an increase in the relative growth rate of the shoot was found to be due to an increase in the relative growth rates of both components. In seventeen clones the relationship between the increments of the two components was constant. In five of the clones an increase in the relative growth rate of the shoot at low values was due more to an increase in the relative growth rate of the number of tillers than to an increase in the relative growth rate of the mean tiller. At high values the opposite occurred.
These results are discussed in relation to the theory of 'nutritive diversion' and in relation to the proportion of lateral buds which produce tillers.     

Kinetic analysis of a general model of activation of aspartic proteinase zymogens involving a reversible inhibitor. II. Contribution of the uni- and bimolecular activation routes

From the kinetic study carried out in part I of this series (preceding article) an analysis quantifying the relative contribution to the global process of the uni- and bimolecular routes has been carried out. This analysis suggests a way to predict the time course of the relative contribution as well as the effect on this relative weight of the initial zymogen, inhibitor and activating enzyme concentrations.     

褐家鼠肥满度的研究

褐家鼠肥满度的研究杨再学,郭世平（贵州省余庆县植保站,５６４４００）ＲｅｌａｔｉｖｅＦａｔｎｅｓｓｏｆＢｒａｎｄ＇ｓＶｏｌｅ（Ｒａｔｔｕｓｎｏｒｖｅｇｉｃｕｓ）．￥ＹａｎｇＺａｉｘｕｅ;ＧｕｏＳｉｐｉｎｇ（ＹｕｑｉｎｇＣｏｕｎｔｙＰｌａｎｔＰｒｏｔｅ...     

A MORPHOMETRIC ANALYSIS OF CELLULAR DIFFERENTIATION IN THE ROOT CAP OF ZEA MAYS

In order to quantify the ultrastructural changes associated with cellular differentiation, we have performed a morphometric analysis of the ultrastructure of the calyptrogen, columella, and peripheral cells of the root cap of Zea mays. The relative volumes of the nucleus, nucleolus, and mitochondria in the protoplasm gradually decrease as a cell moves through the root cap. The relative volume of plastids increases 240% during the differentiation of calyptrogen cells into columella cells. This increase is transient, however, since the relative volume of plastids as well as starch in plastids decreases markedly as columella cells differentiate into peripheral cells. Dictyosomes and spherosomes increase more gradually than plastids, peaking in relative volume in the innermost peripheral cells (PCI). The relative volume of the vacuome decreases as calyptrogen cells differentiate into columella cells, after which it increases during the differentiation of peripheral cells. By the time the outermost peripheral cells (PCIII) are sloughed from the cap, the relative volume of the vacuome has almost tripled. These results indicate that each cell type comprising the root cap of Zea mays is characterized by a distinctive ultrastructure. Furthermore, the ultrastructural changes associated with the differentiation of these cells are organelle specific. The results of this study are discussed relative to the function of the various cell types of the root cap.     

The Influence of Relatives on the Efficiency and Error Rate of Familial Searching

We investigate the consequences of adopting the criteria used by the state of California, as described by Myers et al. (2011), for conducting familial searches. We carried out a simulation study of randomly generated profiles of related and unrelated individuals with 13-locus CODIS genotypes and YFiler® Y-chromosome haplotypes, on which the Myers protocol for relative identification was carried out. For Y-chromosome sharing first degree relatives, the Myers protocol has a high probability () of identifying their relationship. For unrelated individuals, there is a low probability that an unrelated person in the database will be identified as a first-degree relative. For more distant Y-haplotype sharing relatives (half-siblings, first cousins, half-first cousins or second cousins) there is a substantial probability that the more distant relative will be incorrectly identified as a first-degree relative. For example, there is a probability that a first cousin will be identified as a full sibling, with the probability depending on the population background. Although the California familial search policy is likely to identify a first degree relative if his profile is in the database, and it poses little risk of falsely identifying an unrelated individual in a database as a first-degree relative, there is a substantial risk of falsely identifying a more distant Y-haplotype sharing relative in the database as a first-degree relative, with the consequence that their immediate family may become the target for further investigation. This risk falls disproportionately on those ethnic groups that are currently overrepresented in state and federal databases.     

男性青少年脂肪组织分布与相对骨龄的关系——Fels追踪研究

本文对Fels追踪研究中8—17岁男性青少年的相对骨龄与脂肪分布类型之间的关系做了分析。按体重/身高~2调整后,如用每个年龄的三种皮褶厚度(ST)指数的均值表示脂肪分布类型的话,8—12岁时,脂肪分布类型呈外周型分布,但13岁后开始朝向心型发展呈全身性分布。如用肩胛下ST/(肩胛下ST+肱三头肌区ST)的比例表示的话,那么14—17岁时,相对骨龄早者(简称早组)与相对骨龄晚者(简称晚组)相比,前者有较明显的向心型分布倾向。13—14岁时,早组的上述比值的年增长明显大于晚组。但是,按脂肪分布类型指数等级的基线和体重/身高~2调整之后,7、11或14岁时的相对骨龄不能预测17岁时的脂肪分布类型指数的等级。所以,我们可以得出这样的结论:如按本文的比例指数加以定量的话,脂肪分布类型与男性青少年的相对骨龄只有微弱的关系。他们的脂肪分布类型可能与其它成熟指征(如男性青春期的第二性征)有明显的关系。     

Respiration and Vitality of Binucleate and Trinucleate Pollen

The respiration and vitality of ungerminated bi- and trinucleate pollen were studied in order to determine the influence of relative humidity and temperature on metabolic activity. The gas exchange, germination capacity and staining with tetrazolium bromide were followed under standardized conditions. A constant respiration rate occurred under conditions of high relative humidity (97%). Per mg pollen, the trinucleate grains of Compositae and Gramineae respired 2 to 3 times as intense as 6 species of binucleate grains. Per unit of pollen protein the differences were even larger. In contrast to binucleate pollen, the longevity of trinucleate pollen was very short and the ability to germinate was lost twice as fast as the respiration capacity. This limits the use of tetrazolium bromide as an indicator of viability. At reduced relative humidities respiration was strongly restricted, but the longevity of bi- and trinucleate pollen considerably increased. Pollen of Gramineae, however, was very sensitive to changes in relative humidity; short exposure to low relative humidity decreased both the vitality and the capacity to respire.     

Relative importance of strength, power, and anthropometric measures to jump performance of elite volleyball players

The purpose of this investigation was to examine the potential strength, power, and anthropometric contributors to vertical jump performances that are considered specific to volleyball success: the spike jump (SPJ) and counter-movement vertical jump (CMVJ). To assess the relationship among strength, power, and anthropometric variables with CMVJ and SPJ, a correlation and regression analysis was performed. In addition, a comparison of strength, power, and anthropometric differences between the seven best subjects and the seven worst athletes on the CMVJ test and SPJ test was performed. When expressed as body mass relative measures, moderate correlations (0.53-0.65; p < or = 0.01) were observed between the 1RM measures and both relative CMVJ and relative SPJ. Very strong correlations were observed between relative (absolute height-standing reach height) depth jump performance and relative SPJ (0.85; p < or = 0.01) and relative CMVJ (0.93; p 相似文献   

SEASONAL VARIATION IN THE VOLATILE TERPENOIDS OF JUNIPERUS SCOPULORUM (CUPRESSACEAE)

Fifteen trees in a natural population of Juniperus scopulorum Sarg. were sampled at 4-week intervals throughout a year and the terpenoid constituents were extracted from the foliage. Several environmental variables were measured. Correlations with changes in volatile oil composition (computed as both relative percentages and as weights) were examined. Significant seasonal variations were discovered in both the relative percentage and weight data. These seasonal changes in the volatile oil composition were correlated with linear growth, temperature, yield of volatile oil, and dry weight of foliage. Seasonal variation in the terpenoids computed on a weight basis was found to be greater than the seasonal variation of the terpenoids computed as relative percents of the total oil. Evidence is presented which indicates that there is no stable period to sample on a weight basis, but sampling in the late fall and winter periods minimizes variation in the relative percentage data. The use of relative percentage data is thus encouraged for chemosystematic studies.     

Response of specific transfer-ribonucleic-acid levels to amino-acid deprivation in Friend leukemia cells.

In eukaryotes, the levels of specific tRNAs are closely correlated with the demands for their cognate amino acids in protein synthesis. To account for this phenomenon, we have proposed that the extent of aminoacylation of a given tRNA species in vivo controls the relative rate of synthesis or turnover of that species. Previously, we reported that Friend leukemia cells respond to histidine deprivation by increasing their relative level of tRNAHis by as much as two-fold, with no change in the relative level of tRNALeu. In this paper, we show that deprivation of leucine or tryptophan also causes a specific increase in the relative level of tRNAs cognate to the deprived amino acid. At least in the case of tRNATrp, the increases in relative tRNA levels are preceded by extensive declines in the steady-state extent of aminoacylation of the tRNA in vitro. We also find that different isoacceptors may respond differently to amino acid deprivation. These results suggest that decreased extents of aminoacylation of a given tRNA species in vivo cause increases in the relative rate of synthesis or decreases in the relative rate of degradation of that species.     

Comparison of morphological and molecular genetic quantification of relative abundance of arbuscular mycorrhizal fungi within roots

Nested PCR amplicons of ribosomal RNA genes have been used to identify individuals within assemblages of arbuscular mycorrhizal (AM) fungi in roots and to estimate their relative abundance. Microscopy has also been used to identify their relative abundance in roots, but only at low resolution, usually the genus level. We evaluated the robustness of using nested PCR amplicons of ribosomal RNA genes to estimate the relative abundance of undefined AM fungi in uniformly aged roots in comparison to visual estimates. The relative abundance of AM fungi was assessed as per cent root length colonised by morphotypes and relative sequence type abundance in clone libraries. Plants were grown in coastal soil to obtain assemblages of unknown AM fungi at two times (spring and autumn). Relative abundance of dominant genera of AM fungi in roots (Archaeospora and Glomus) based on an analysis of ribosomal RNA genes did not consistently correspond with relative abundance of morphotypes. This microscopic vs. molecular genetic comparison supports previous conclusions that there can be limitations in using nested PCR amplicons for quantifying the relative abundance of AM fungi in roots, with a sampling bias likely to be of significance. Both molecular genetic and morphological methods are used to estimate relative abundance of AM fungi as a precursor to understanding mycorrhizal function in field soils, but they are rarely verified using alternative approaches although this may be necessary.     

Foreignness as a matter of degree: the relative immunogenicity of peptide/MHC ligands

The ability of T lymphocytes (T cells) to recognize and attack foreign invaders while leaving healthy cells unharmed is often analysed as a discrete self/non-self dichotomy, with each peptide/MHC ligand classified as either self or non-self. We argue that the ligand immunogenicity is more naturally treated as a continuous quantity, and show how to define and quantitate relative ligand immunogenicity. In our theory, self-tolerance is acquired through reduction of the relative immunogenicity of autoantigens, whereas xenoantigens, typically not presented during induction of deletional tolerance, retain a high degree of relative immunogenicity. Autoantigens that are not prominently presented in deletional tolerance likewise retain a high relative immunogenicity and remain essentially foreign. According to our analysis, any given autoantigen can attain a high level of relative immunogenicity, provided it is presented at sufficiently high levels. Our theory provides a quantitative tool to analyse the immunogenicity of tumour-associated neoantigens and the ætiology of autoimmune disease.     

Transfer Efficiency of Bacteria and Viruses from Porous and Nonporous Fomites to Fingers under Different Relative Humidity Conditions

Fomites can serve as routes of transmission for both enteric and respiratory pathogens. The present study examined the effect of low and high relative humidity on fomite-to-finger transfer efficiency of five model organisms from several common inanimate surfaces (fomites). Nine fomites representing porous and nonporous surfaces of different compositions were studied. Escherichia coli, Staphylococcus aureus, Bacillus thuringiensis, MS2 coliphage, and poliovirus 1 were placed on fomites in 10-μl drops and allowed to dry for 30 min under low (15% to 32%) or high (40% to 65%) relative humidity. Fomite-to-finger transfers were performed using 1.0 kg/cm² of pressure for 10 s. Transfer efficiencies were greater under high relative humidity for both porous and nonporous surfaces. Most organisms on average had greater transfer efficiencies under high relative humidity than under low relative humidity. Nonporous surfaces had a greater transfer efficiency (up to 57%) than porous surfaces (<6.8%) under low relative humidity, as well as under high relative humidity (nonporous, up to 79.5%; porous, <13.4%). Transfer efficiency also varied with fomite material and organism type. The data generated can be used in quantitative microbial risk assessment models to assess the risk of infection from fomite-transmitted human pathogens and the relative levels of exposure to different types of fomites and microorganisms.     

Relative addition rate and external concentration; Driving variables used in plant nutrition research

Abstract An increasing literature accounting for various types of experiments indicates that far lower external nutrient concentrations are required by plants than is usually thought to be the case. It is concluded that the ion uptake capacity of the roots, as described by the carrier concept, is high compared to that required for maintenance of the internal concentration. Serious errors in experimental conclusions are associated with insufficient and constant nutrient addition rates. The main errors are caused by non-steady states of the plants both with regard to the internal nutrient concentrations and the relative growth rate. A dynamic concept has been proposed for direct use as the treatment variable within the range of sub-optimum nutrition. The nutritional factor is expressed as a flow, the relative nutrient addition rate in laboratory studies and the nutrient flux density in the field. The experimental use of the relative addition rate has led to steady-state nutrient status and relative growth rate and the interpretation of plant responses which differ fundamentally from accepted views. Thus, for instance, deficiency symptoms disappear, as in natural conditions, when the internal nitrogen concentration is stable, independent of level. The nutrition/growth relationships are very different from those observed when external concentration is varied. The regression line of relative growth rate on relative addition rate passes near to the origin at an angle close to 45 to the axes, which implies that the obtained relative growth rate approximates closely the treatment variable. A striking example of observed differences is the positive effect on nitrogen fixation exerted by high relative nitrogen addition rates compared to the well-known negative effect of increasing external nitrogen concentration. The application of fertilizer on the basis of the nutrient flux density concept provides the possibility of supplying fertilizers corresponding to the consumption potential of the vegetation and to the natural flux density resulting from mineralization in the soil. Nitrogen utilization is high under such conditions and the resulting feedback of nutrition on the mineralization rate suggests that there will be a long-term increase in fertility.     

Relative Age Effects in Dutch Adolescents: Concurrent and Prospective Analyses

The literature on relative age position effects is rather inconsistent. In this study we examined intra-classroom age position (or relative age) effects on Dutch adolescents’ school progress and performance (as rated by teachers), physical development, temperamental development (fear and frustration), and depressive symptoms, all adjusted for age at the time of measurement. Data were derived from three waves of Tracking Adolescents'' Individuals Lives Survey (TRAILS) of 2230 Dutch adolescents (baseline mean age 11.1, SD = 0.6, 51% girls). Albeit relative age predicted school progress (grade retention ORs = 0.83 for each month, skipped grade OR = 1.47, both p<.001), our key observation is the absence of substantial developmental differences as a result of relative age position in Dutch adolescents with a normative school trajectory, in contrast to most literature. For adolescents who had repeated a grade inverse relative age effects were observed, in terms of physical development and school performance, as well as on depressive symptoms, favoring the relatively young. Cross-cultural differences in relative age effect may be partly explained by the decision threshold for grade retention.     

Body, heart, thyroid gland and skeletal muscle weight changes in rats with altered thyroid status

In the present paper we describe changes of anatomical parameters in inbred Lewis strain rats, namely their body weight, body weight gain per week, absolute and relative heart, thyroid gland and skeletal muscle weights, that are assumed to reflect experimentally altered thyroid status. The hyperthyroid state was induced by DL-thyroxine or Na 3,3',5-triiodo-L-thyronine, while methimazole was employed for inducing hypothyroidism. We have found that when compared to euthyroid rats, hypothyroidism resulted in a significantly lower body weight gain, absolute and relative heart weight and, in contrast, in a significant increase of absolute and relative thyroid gland weight. On the other hand, hyperthyroidism led to a significant increase of absolute and relative heart weight and to a significant reduction of absolute and relative thyroid gland weight. However, the body mass was not significantly altered in hyperthyroidism as compared with euthyroid rats. We conclude that our protocol leads to chronic hyper- or hypothyroidism as demonstrated by body, heart and thyroid gland weight changes. These anatomical data can thus be utilized as supplemental criteria for the assessment of the thyroid state of experimental rats.     

外源多氨基芳香族化合物对高温强光下芦苇离体叶绿体叶绿素降解的缓解作用

以甘肃省河西走廊临泽县境内荒漠地区2种生态型芦苇为主要研究材料,研究了在添加多氨基芳香族化合物(Mr856,PAAC)条件下,不同温度、光照强度处理及处理时间对沙芦和水芦离体叶绿体叶绿素相对含量的影响,以探究PAAC对高温强光条件下离体叶绿体可能的保护机理。结果表明:(1)外源PAAC对水芦和沙芦离体叶绿体叶绿素相对含量的影响因环境光照强度、温度和处理时间的不同而异;(2)光照强度对离体叶绿体叶绿素相对含量的影响与温度有关,且随着处理时间的延长而增强,在光照水平为1 000μmol.m-2.s-1下,沙芦叶绿素相对含量在不同温度下均高于水芦;(3)外源PAAC可明显减缓高温强光胁迫下水芦叶绿素相对含量的降低趋势,尤其对强光胁迫下叶绿素相对含量降低的效应更明显。研究结果说明,PAAC可能作为沙芦叶片中具独特分子结构特征的相容性溶质,可减缓高温强光下离体叶绿体叶绿素的降解,对离体叶绿体有一定的保护作用。