贵阳城市污水处理厂污泥生产轻质陶粒的研究

贵阳市小河污水处理厂以机械脱水污泥为原料,配以页岩、少量锯末及玻璃粉,摸拟贵州坤泰建材工贸有限公司粘土陶粒厂生产工艺,经练泥搅拌、挤压成球、预热焙烧（焙烧温度1050℃并保温30min）等各生产工序,成功生产出不同密度等级的普通轻质陶粒。     

Metribuzin impairs the unicell-colony transformation in the green alga Scenedesmus obliquus

Active growth is a prerequisite for the formation of grazing-protective, mostly eight-celled colonies by the ubiquitous green alga Scenedesmus in response to chemical cues from zooplankton. Colonies can also be evoked by chemically quite similar manmade anionic surfactants, such as FFD-6. In this study, it was hypothesized that growth-inhibiting concentrations of the herbicide metribuzin impair the ability of Scenedesmus obliquus to form colonies in response to the surfactant morphogen FFD-6. The results confirmed that the formation of colonies in S. obliquus was hampered by metribuzin. EC₅₀ values of metribuzin for colony inhibition (approximately 11 μg L⁻¹) were similar to those for growth and photosynthesis inhibition (12-25 μg metribuzin L⁻¹). In the absence of the colony-inducing surfactant FFD-6, S. obliquus populations were comprised of 92% unicells, having on average 1.2 cells per colony at all tested metribuzin concentrations (0-100 μg L⁻¹). In contrast, in the presence of FFD-6 and at low metribuzin concentrations (0 and 5 μg L⁻¹), S. obliquus had more than five cells per colony with a high portion of eight-celled colonies. However, increasing concentrations of metribuzin decreased the number of colonies in the FFD-6-exposed populations and caused them to remain mostly unicellular at the highest concentrations (50 and 100 μg L⁻¹). This study revealed that metribuzin impeded growth and by doing so, also obstructed the possibility for unicellular Scenedesmus to form colonies. Consequently, an increase in mortality of Scenedesmus from grazing is expected.     

基于双剪屈服条件的输油管道腐蚀剩余强度可靠性研究

提出基于双剪屈服塑性极限条件的管道可靠性爆破压力可靠度模型,在基于剩余强度可靠性理论基础上,着重分析随机参数,即腐蚀深度、腐蚀长度和运行压力的分布情况,通过经典可靠性计算方法、JC法将非正态分布转化成标准正态分布,从而建立起基于双剪屈服条件的管道腐蚀可靠性计算模型。通过提取现场实验数据进行验算,其结果表明:双剪屈服强度理论算得的爆破压力更接近实验结果,该方法降低API579的保守性,大大提高了可靠性的计算精度。     

Differentiated phenotypic plasticity in larvae of the cannibalistic salamander Hynobius retardatus

Alternative phenotypes in natural populations can arise from either genetic polymorphism or an environmentally induced phenotype, that is, polyphenism. Evolutionary models of polyphenism developed by theoretical studies predict that polyphenism is favored when there are environment-dependent fitness trade-offs between alternatives and that the threshold frequency for a facultative switch between alternative phenotypes is adjusted in accordance with different selection regimes. The broad-headed (alternative) larval morph of Hynobius retardatus, which is induced by crowding with conspecifics or heterospecific anuran (Rana pirica) larvae, is a representative example of cannibalistic polyphenism. Morph induction by such proximate factors must reflect evolutionary (conditional frequency-dependent) processes. To clarify the role of frequency-dependent processes in polyphenism, I investigated the occurrence rate of the broad-headed morph under experimental crowding conditions (low conspecific, high conspecific, and high heterospecific densities) using larvae from eight natural populations with different larval densities of conspecifics and heterospecifics, and found interpopulational differences in the expression of the morph. Thus, there is a larval density-dependent equilibrium frequency of the morph in each pond, suggesting that the local switch point for morph induction was modified by selection to produce evolved differences between ponds. The evolution of such interpond differences has three necessary conditions: (1) There are pond-dependent fitness trade-offs between alternatives, (2) The maintenance of the morph is costly, and (3) The presence of conspecific or, especially, heterospecific larvae provides a reliable cue to the receiver.     

Sperm traits in the quacking frog (<Emphasis Type="Italic">Crinia georgiana</Emphasis>), a species with plastic alternative mating tactics

In species where males use alternative reproductive tactics and male phenotypes are confronted with different risks of sperm competition, theory predicts that between-male-type differences in sperm expenditure may evolve. In the frog Crinia georgiana big males can monopolize females, whereas small males often engage in polyandrous matings. Consequently, big males may experience a lower risk of sperm competition than do small males. We tested if the predictions from theoretical models can be applied to the mating system of C. georgiana. Our results showed that small males do not have larger testes relative to their body size compared to their larger counterparts and that the efficiency with which sperm number, size, motility, and longevity are produced by the testes does not differ between small and large males in the predicted way. These results are not in alignment with predictions from a loaded raffle model of sperm competition on sperm expenditure in males with alternative phenotypes. The plasticity in mating tactics used by C. georgiana males and a high intraseasonal variation in male densities may have prevented the evolution of enhanced sperm performance in smaller males. A fair raffle in the sperm competition game played by C. georgiana males could also explain the observed patterns in sperm traits. Future investigations determining the parameters responsible for the deviation from theoretical predictions in this system will test the degree to which current theoretical models can indeed be applied to species with plastic reproductive tactics.     

Phenotypic diversity in populations of the common blue butterfly <Emphasis Type="Italic">Polyommatus icarus</Emphasis> Rott. As a trend in the ecocenotic strategy of the species

Phenotypic diversity in populations of Polyommatus icarus Rott. (Lepidoptera, Lycaenidae) is regarded as a component of the ecocenotic strategy of the species, trends in which may serve as markers characterizing the state of natural populations.     

Impacts of environmental heterogeneity on alternative mating tactics in the threadtail damselfly

Environmental heterogeneity, including variation in the physical environment, may be key to understanding the evolution and maintenance of alternative mating tactics, but its influence is rarely examined. Males of the threadtail damselfly Protoneura amatoria reversibly use two alternative mating tactics (perching vs. hovering) and have previously been found to modulate their use of these tactics in response to variation in both light conditions and the density of ovipositing females. Here, I show that mating success payoffs of the two tactics are differentially influenced by these factors. The payoff of the perching tactic was greater than that of the hovering tactic under low light conditions and at low densities of ovipositing females. The payoff of the hovering tactic was greater under high light conditions and higher densities of ovipositing females. The differential success of the two mating tactics in response to light conditions is discussed in light of flight dynamics, vision, and predation.     

On the effect of climate on the morphological structure of <Emphasis Type="Italic">Alnus hirsuta</Emphasis> (Betulaceae)

An analysis of correlations between metric leaf characters and climatic parameters of habitats in the Siberian alder (Alnus hirsuta) has shown that phenotypic variation in this species depends on the gradient of climatic factors and that the morphological structure of the species is largely determined by variation in climatic conditions within the species range.     

五爪金龙不同部位化感作用可塑性变化

为探讨五爪金龙化感作用可塑性,利用生物检测法研究了五爪金龙不同部分水提液对莴苣种子萌发的影响,结果表明:经过长期的适应和进化,五爪金龙不同部位化感作用变化幅度具有不同程度的差异;随水提液质量浓度的增加,五爪金龙植株整体化感作用变化范围增加,不同部位之间化感作用变化幅度差异加大。五爪金龙不同部位化感综合效应的质量浓度敏感性大小与其化感作用效率有关。五爪金龙不同部位化感综合效应平均值大小与其95%置信区间不存在协变关系,但其化感综合效应平均值的95%置信区间大小可以表征化感可塑性变化范围。五爪金龙较高的化感作用可塑性有利于增强其种间竞争能力。     

Acquired changes in stomatal characteristics in response to ozone during plant growth and leaf development of bush beans (Phaseolus vulgaris L.) indicate phenotypic plasticity

Bush bean (Phaseolus vulgaris L.) lines 'S156' (O3-sensitive)/'R123' (O3-tolerant) and cultivars 'BBL 290' (O3-sensitive)/'BBL 274' (O3-tolerant) were used to study the effects of O3 on stomatal conductance (gs), density, and aperture size on leaf and pod surfaces with the objective of establishing links between the degree of plant sensitivity to O3 and plasticity of stomatal properties in response to O3. Studies in open-top chambers (OTCs) and in continuously stirred tank reactors (CSTRs) established a clear relationship between plant developmental stages, degrees of O3 sensitivity and gs: while 'S156' had higher gs rates than 'R123' earlier in development, similar differences between 'BBL 290' and 'BBL 274' were observed at later stages. Gs rates on the abaxial leaf surfaces of 'S156' and 'BBL 290', accompanied by low leaf temperatures, were significantly higher than their O3-tolerant counterparts. Exposure to O3 in CSTRs had greater and more consistent impacts on both stomatal densities and aperture sizes of O3-sensitive cultivars. Stomatal densities were highest on the abaxial leaf surfaces of 'S156' and 'BBL 290' at higher O3 concentrations (60 ppb), but the largest aperture sizes were recorded on the adaxial leaf surfaces at moderate O3 concentrations (30 ppb). Exposure to O3 eliminated aperture size differences on the adaxial leaf surfaces between sensitive and tolerant cultivars. Regardless of sensitivity to O3 and treatment regimes, the smallest aperture sizes and highest stomatal densities were found on the abaxial leaf surface. Our studies showed that O3 has the potential to affect stomatal plasticity and confirmed the presence of different control mechanisms for stomatal development on each leaf surface. This appeared to be more evident in O3-sensitive cultivars.