对种群数量增长曲线的探讨

分析2019年全国Ⅰ卷理综的第6题,可得出种群增长的J型和S型增长,以及介于二者之间的增长.同时从现实分析可将S型增长曲线的开始部分视为J型增长曲线,但从模型构建分析却不能将S型增长曲线的开始部分视为J型增长曲线.     

论Richards增长曲线

本文给出了Ｒｉｃｈａｒｄｓ增长曲线一个很好的解析表达式,它使得Ｌｏｇｉｓｔｉｃ增长曲线、Ｇｏｍｐｅｒｔｚ增长曲线与Ｒｉｃｈａｒｄｓ增长曲线之间的关系清晰了,提示了著名的Ｌｏｇｉｓｔｉｃ增长曲线与Ｇｏｍｐｅｒｔｚ增长曲线是Ｒｉｃｈａｒｄｓ增长曲线的特殊情形,而且还给出了Ｒｉｃｈａｒｄｓ增长曲线一些很好的特性。     

Gompertz曲线与logistic增长曲线之比较

本文给出了生物增长模型中常用的logistic曲线与Gompertz曲线之间的主要差异与相似处．     

一类具有退偿增长曲线的生物种群的捕获优化问题

本文研究一类具有延偿增长曲线的生物种群,讨论了该种群的动力学性质及捕获问题,确定了最优捕获努力量、相应的种群密度和最大可持续捕获量、讨论了开放条件下的生物资源的管理。     

协方差阵扰动增长曲线模型中回归参数阵B的影响分析

本文利用协方差阵扰动模型讨论增长曲线模型回归参数阵B的影响分析,获得了扰动前后B的最小二乘估计关系式,同时还得到了度量扰动影响的广义Cook距离．     

增长曲线模型回归参数B的影响分析—似然距离法

本文讨论增长曲模型的回归参数Ｂ的影响分析,导出了度量影响大小的似然距离量度ＬＤ,并分析了ＬＤ与广义Ｃｏｏｋ距离的联系,最后的实例应用说明了似然距离统计量度量增长曲线模型的影响点是有效的。     

种群增长模型中的增长率和增长速率的比较

针对在一道高考题中出现的种群增长率与高中必修(人教版)教材中增长率的涵义不同,通过介绍种群增长模型的三种类型,旨在辨析增长率和增长速率.     

逻辑斯谛增长导致的复杂种群动态及其实验验证

教科书通常用“S”型曲线表示逻辑斯谛增长模型导致的种群动态,事实上,这一模型可以产生包括稳定平衡、周期性振荡、混沌等多种多样的种群动态模式。介绍了如何用Kicker图示的方法分析逻辑斯谛增长可能导致的种群动态模式。同时介绍了相关的实验研究案例,这些实验工作大都是以生活史周期较短的昆虫为材料在相对简单的实验室环境中完成的。     

种群数量增长的"增长率"与"增长速率"辨析

在高中生物学教学中,关于种群数量增长的"S"形曲线的斜率称为"增长率"还是"增长速率",一直存在争论.从种群数量增长的3种基本数学模型入手,结合中、英文对照,从这些争论的源头出发,通过总结对比,辨析2种表述方式的合理性.对相关的几个生态学参数进行对比归类,为高中生物学教学提供参考.     

大丰自然保护区麋鹿种群增长模型以及种群密度对种群增长影响的研究

创建了一个关于大丰自然保护区半散养麋鹿种群增长的Logistic模型,该模型准确地预测了麋鹿种群的增长规律.作者通过对比和分析相关数据揭示了种群密度对糜鹿种群增长的影响并给出两个导致种群增长发生改变的临界值.     

Polypeptide Growth Factors in Embryogenesis and Tumor Growth

Polypeptide growth factors belonging to different families (epidermal growth factors, insulin-like growth factors, fibroblast growth factors, transforming growth factors-, and some others), were characterized regarding their specific role in embryogenesis and tumor growth. Differences and parallels in the functioning of growth factors in these processes have been noted. The potential significance of the described characteristics of growth factors for directed modulation of embryogenesis and tumor growth is discussed.     

Schwannoma-Derived Growth Factor Interacts with the Epidermal Growth Factor Receptor

Abstract: Schwannoma-derived growth factor (SDGF) is a potent mitogen and neuronal differentiation factor. Because of its relationship to epidermal growth factor (EGF) and the heregulins, it was asked if SDGF interacts with the EGF receptor or HER2/neu. SDGF binds to and causes the phosphorylation on tyrosine of the EGF receptor but not HER2/neu.     

Growth and morphogenesis in Streptomyces

In this report we propose a model of apical growth for streptomycetes. The apical tip is considered as a multilayered wall that expands by an inside-to-outside mechanism of growth. It is also assumed that each layer is made up of peptidoglycan blocks, each of them being the result of the biosynthetic activity of a wall-synthesizing unit or membrane-associated growth zone. According to our model, apical growth occurs as follows: as a consequence of the hydrostatic pressure and the cleavage of some bonds, the layers are pushed and forced to slide (one with respect to the other), migrating from the center of the tip (at the inside of the wall) towards a peripheral location (at the outside of the wall). The model also incorporates a mechanism by which apical growth can be regulated and coordinated with the replication of the chromosome.     

生长激素分泌促进剂及构效关系研究进展

生长激素分泌促进剂是一类作用于垂体和下丘脑的具有专一性促生长激素释放作用的寡肽及其类似物.由于其分子质量小、活性高、可口服、作用专一而有可能成为新的生长激素治疗药物.目前已经发展了很多具有此类活性的多种结构的化合物,如肽、环肽、肽醇及非肽类似物等.尽管这类化合物的作用机制尚未完全明确,但已有证据表明存在新的调节生长激素分泌的途径和新的调节因子.     

Hydrocarbon Leaching, Microbial Population, and Plant Growth in Soil Amended with Petroleum

Two samples of oily waste organics (OWO) from petroleum wells were added to heath soils from Tierra del Fuego, Argentina, and the effects on hydrocarbon leaching, microbial population, and plant growth were studied. These mixtures and a control soil were subjected to four deionized water leachates. For each leachate, total petroleum hydrocarbons (TPH), aliphatic hydrocarbons (ALH), aromatic hydrocarbons (ARH) with three or fewer rings, ARH with more than three rings, and oil and grease (O&G) were measured. After leaching, six Dactylis glomerata L. plants were grown in each soil column. Plant growth and the total number of aerobic and nitrifier microorganisms were measured in soil. The 10% OWO sample increased the TPH in the leachate, but the 1% sample did not. The ALH, ARH, and O&G of each leachate followed patterns similar to that for TPH. Plant growth diminished and the total number of aerobic and nitrifier microorganisms decreased with increasing OWO, especially when the OWO was from a fresh residue rather than an aged residue. The greater inhibitive effect of fresh residue on plant growth was attributed to a higher concentration of light hydrocarbons, which are more toxic than heavy hydrocarbons. For soil with 1% OWO added, the TPH and other organics did not differ from the control soil. This result, combined with the 10-year average annual rainfall and the water table elevation at the site, suggests that the risk of contaminating the water table is relatively low. Thus, a 1% addition of OWO in soil would be appropriate to use in landfarming of OWO.     

Insulin-Like Growth Factor I Receptor Expression and Function in Nerve Growth Factor-Differentiated PC12 Cells

Abstract: Receptors for insulin-like growth factor I (IGF-I) were studied on PC12EY cells, a subclone of PC12. Differentiation of PC12EY cells with nerve growth factor (NGF) did not alter either the number of IGF-I receptors nor their affinity for IGF-I. IGF-I receptors remained fully functional during differentiation, promoting increases in thymidine incorporation, glucose uptake, amino acid uptake, and the phosphorylation of the S6 protein of the ribosomes. IGF-I also increased the proportion of differentiated cells found in S-phase. But although the addition of IGF-I to naive cells caused an increase in cell number, there was no comparable increase when IGF-I was added to differentiated cells. Thus, although the receptor for IGF-I continues to be present and functional, IGF-I fails to induce cell proliferation in differentiated PC12 cells.     

微球包裹pcDNA3-GRF（1-32）在小鼠肌肉组织的表达及对生长的影响

以乳酸-乙醇酸共聚物为载体,采用复乳液中蒸发法制备载生长激素释放因子（Growth hormone releasing factor,GRF）真核表达质粒pcDNA3-GRF（1-32）微球,其中包封率达69%,平均粒径为2.20μm,载药量80μg/mg,收率70%;体内转染小鼠肌肉组织, 提取注射部位肌肉组织DNA 和总RNA,经PCR和RT-PCR,发现注射pcDNA3-GRF（1-32）微球组的GRF表达水平最高（UVIBAND Version 99分析）,释放的GRF表达质粒在小鼠肌肉内存在并表达的时间至少30d。体重统计结果表明,30d后微球包裹质粒组累积增重与其它组相比差异极显著（P<0.01）,比裸质粒组、质粒和空白微球混合物组、生理盐水组分别高12.87%,19.72%,58.58%;结论认为,载pcDNA3-GRF（1-32）微球具有缓释作用,并可实现GRF基因体内局部基因转染、表达,发挥其相应的生物学效应,有希望成为提高质粒在动物肌肉组织表达效率的新方法。     

Growth,graviresponsiveness and abscisic-acid content of Zea mays seedlings treated with Fluridone

Ten-d-old seedlings of Zea mays L. cv. Tx 5855 treated with 1-methyl-3-phenyl-5-(3-[trifluoromethyl]phenyl)-4-(1H)-pyridinone (Fluridone) were analyzed for abscisic acid (ABA) content using high-performance liquid chromatography with an analysis sensitivity of 2.5 ng ABA g^-1 fresh weight (FW). Seedlings were divided into three portions: leaves, detipped roots, and root tips (terminal 1.5 mm). Control plants (water treatment only; no Fluridone) were characterized by the following amounts of ABA: leaves, 0.114±0.024 (standard deviation) g ABA g^-1 FW; detipped roots, 0.260±0.039±g ABA g^-1 FW; root tips, no ABA detected. We did not detect any ABA in tissues of Fluridone-treated plants. Primary roots of treated and untreated seedlings were strongly graviresponsive, with no significant differences between the curvatures or the growth rates of primary roots of Fluridone-treated and control seedlings. These results indicate that 1) Fluridone completely inhibits ABA synthesis, and 2) ABA is not necessary for positive gravitropism by primary roots of Zea mays.Abbreviations ABA abscisic acid - Fluridone 1-methyl-3-phenyl-5-(3-[trifluoromethyl]phenyl)-4-(1H)-pyridinone - FW fresh weight - SD standard deviation     

水分对胡杨幼苗光合及生长特性的影响

采用盆栽控制实验方法对不同水分条件下胡杨幼苗的光合日变化以及生长特性进行分析研究.结果显示:(1)不同水分条件下胡杨幼苗的净光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)和蒸腾速率(Tr)日变化曲线均呈单峰型,峰值时间均在12:00;当土壤含水量为21.6%～24.0%时,幼苗的水分利用效率(WUE)日变化曲线呈不明显的双峰型,峰值时间分别在8:00和18:00,其他处理均为单峰型,但峰值时段有差异;随着土壤含水量的减小,胡杨幼苗的Pn、Gs、Ci和Tr日均值逐渐降低,当土壤含水量为12.0%～19.2%时,幼苗的WUE日均值显著高于其他处理.(2)幼苗的株高、基径、各器官的生物量及总生物量均随土壤含水量的减小而降低,当土壤含水量为12.0%～19.2%时,幼苗地下生物量的降低程度大于地上生物量,且幼苗的根冠比也增大.研究表明,土壤含水量对胡杨幼苗的光合特性及其生长具有显著影响,当土壤含水量大于12.0%时,幼苗能够通过增大水分利用效率,改变根冠比提高抗旱性;当土壤含水量小于9.6%时,幼苗自我调节能力减弱,生长受到抑制.     

农杆菌对大麦种子萌发及幼苗生长发育的影响

以大麦品种(系)为主区('云引大麦Ⅰ'、'云引大麦Ⅱ'和'U008'),农杆菌浸种时间为副区(0.5、1.5和2.5 h),农杆菌菌液浓度为副副区(0.5、1.5和2.5 OD),采用再裂区试验研究了农杆菌浸种处理对大麦种子萌发和幼苗生长发育的影响.结果表明:品种、农杆菌菌液浓度、浸种时间对大麦的种子发芽率、幼苗高度、幼苗鲜重、叶绿素含量、丙二醛(MDA)含量影响无显著的互作效应,而对幼苗POD活性的影响存在显著互作效应;随着浸种时间的延长和菌液浓度的增加,各大麦品种(系)的种子发芽率、幼苗高度、幼苗鲜重、叶绿素含量均呈逐渐降低趋势,幼苗MDA含量则逐渐增加,并以'U008'变化幅度最大;在菌液浓度为0～1.5 OD、浸种时间为0～1.5 h范围内,幼苗POD活性随着菌液浓度的增加和浸种时间的延长而增强,超过该范围则均呈下降趋势,并以'U008'下降最为明显.可见,农杆菌处理对大麦种子萌发和幼苗生长发育有抑制作用,并在菌液浓度超过1.5 OD、浸种时间大于1.5 h时达极显著水平,且大麦品种间存在一定差异.