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1.
多效唑是一种新开发的植物生长调节剂类农药。试验采用微生物毒性检测的力法,以混合细菌为材料,研究多效唑对细菌的生长速度、总脱氢酶活性和硝化作用的影响。结果表明,多效唑属低毒性农药,在一定范围内,各观察指标与多效唑浓度呈显著性负相关,即较低浓度的多效唑对细菌的生理活动有一定的刺激作用。 相似文献
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植物生理模型用于森林水文气候效应的研究 总被引:2,自引:0,他引:2
论文阐述了植物生理数学模型在对森林的水文气候效应的研究中所能起和应起的作用。从树木的多年生习性和宜林山地的复杂地形等因素论证植物生理数学模型对制订造林优化方案、乔灌草关系等方面所起的作用。论述了植物生理模型与土壤模型、微气象之间结合的必要性。 相似文献
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根据塔里木河下游受生态输水影响的断面和未受输水影响断面的胡杨生理指标脯氨酸、脱落酸和叶片含水量的变化,就胡杨生理指标对生态输水的响应进行了初步分析.结果显示:①在受到生态输水影响的断面,胡杨叶相对含水量增加,脯氨酸、脱落酸因水分条件的好转而分解降低;在未受到生态输水影响的断面,因为干旱胁迫程度的加重,胡杨叶相对含水量减少,脯氨酸、脱落酸因积累而增加.②在生态输水前,胡杨生理指标总体上与地下水位变化相一致,即:随着地下水位的降低,胡杨脯氨酸和脱落酸水平增加;随地下水位的升高,脯氨酸和脱落酸水平有降低的趋势.③从个别数据的异常看,在塔里木河下游,当地下水位较低时,地下水位的升降仅是影响胡杨干旱胁迫的一个因子.因此,在塔里木河下游开展的生态输水工程,对该区胡杨生长的影响非常显著,它在一定程度上缓解了胡杨水分的亏缺,减轻了干旱胁迫程度. 相似文献
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促进植物提取技术高效修复镍污染土壤的方法 总被引:2,自引:1,他引:1
随着对重金属超富集植物研究的加深,用植物提取技术来改良镍污染土壤已逐步进入实用阶段。在此所探讨的提高此技术功效的方法基于2个方面:提高土壤溶液中镍的浓度,促进植物对镍的吸收;根据已了解的超富集的生理机制可能采取的一些措施。 相似文献
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Thomas S. Muenz Alban Maisonnasse Erika Plettner Yves Le Conte Wolfgang R?ssler 《Die Naturwissenschaften》2012,99(5):421-425
Social work force distribution in honeybee colonies critically depends on subtle adjustments of an age-related polyethism. Pheromones play a crucial role in adjusting physiological and behavioral maturation of nurse bees to foragers. In addition to primer effects of brood pheromone and queen mandibular pheromone—both were shown to influence onset of foraging—direct worker–worker interactions influence adult behavioral maturation. These interactions were narrowed down to the primer pheromone ethyl oleate, which is present at high concentrations in foragers, almost absent in young bees and was shown to delay the onset of foraging. Based on chemical analyses, physiological recordings from the antenna (electroantennograms) and the antennal lobe (calcium imaging), and behavioral assays (associative conditioning of the proboscis extension response), we present evidence that ethyl oleate is most abundant on the cuticle, received by olfactory receptors on the antenna, processed in glomeruli of the antennal lobe, and learned in olfactory centers of the brain. The results are highly suggestive that the primer pheromone ethyl oleate is transmitted and perceived between individuals via olfaction at close range. 相似文献
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D. Platt 《Die Naturwissenschaften》1983,70(1):15-22
After a short introduction of the main theories of aging the physiological and pathological alterations of such organs are described which influence absorption, distribution, metabolism and elimination of drugs. In addition the importance of the transport systems (proteins, red cells) is pointed out. Finally some short remarks on the so-called “geriatrika”. 相似文献
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The complexity of nectar: secretion and resorption dynamically regulate nectar features 总被引:2,自引:0,他引:2
In this paper, we review the phenomenon of nectar resorption, focusing on its physiological and ecological meaning. Nectar
resorption is a phenomenon that has long been known but was rarely reported until the1990s. It has more recently been demonstrated
in several species by various direct and indirect methodologies. It has generally been demonstrated in senescent flowers as
a phenomenon separate in time from, and independent of, nectar secretion. The significance of this type of resorption is generally
recognized as a resource-recovery strategy, recycling at least some materials invested in nectar production. Nevertheless,
nectar resorption can occur concomitantly with nectar secretion. Nectar production is therefore best considered as a unified
process comprising nectar secretion and resorption. The modulation of these two opposite phases allows nectar concentration
to be maintained in a range suitable for pollinators (nectar homeostasis). The mechanism of nectar resorption at the cell
level has received little attention, and its molecular basis can only be hypothesized on the basis of recent studies concerning
sugar sensing. 相似文献
9.
5种水生植物去污抗逆能力的试验研究 总被引:21,自引:2,他引:19
在实验室人工模拟太湖地区初春较寒冷的气象条件下,对5种能越冬的水生植物(伊乐藻、微齿眼子菜、竹叶眼子菜、石菖蒲和水芹菜)在不同营养条件下去除氮磷的效果和一些反映其抗逆能力的生理生化指标进行了系统的对比研究.结果表明:这5种植物均能较好地吸收水中的营养物质,其中以水芹菜和微齿眼子菜的脱氮除磷效果最好;5种植物体内脯氨酸含量均与水体营养物质的质量浓度呈正相关,相同试验条件下,水芹菜和微齿眼子菜体内脯氨酸的积累倍数最高,表明二者的抗逆能力也较强;但当水体营养物质的质量浓度超过一定限值后,5种植物的生物量增长率均随水体营养等级的增高而下降.水芹菜和微齿眼子菜可作为构成双层次群落结构(FAMS)的优选植物种类,用于修复太湖地区富营养化水体. 相似文献
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Despite a reasonable scientific interest in sexual selection, the general principles of health signalisation via ornamental
traits remain still unresolved in many aspects. This is also true for the mechanism preserving honesty of carotenoid-based
signals. Although it is widely accepted that this type of ornamentation reflects an allocation trade-off between the physiological
utilisation of carotenoids (mainly in antioxidative processes) and their deposition in ornaments, some recent evidence suggests
more complex interactions. Here, we further develop the models currently proposed to explain the honesty of carotenoid-based
signalisation of heath status by adding the handicap principle concept regulated by testosterone. We propose that under certain
circumstances carotenoids may be dangerous for the organism because they easily transform into toxic cleavage products. When
reserves of other protective antioxidants are insufficient, physiological trade-offs may exist between maintenance of carotenoids
for ornament expression and their removal from the body. Furthermore, we suggest that testosterone which enhances ornamentation
by increasing carotenoid bioavailability may also promote oxidative stress and hence lower antioxidant reserves. The presence
of high levels of carotenoids required for high-quality ornament expression may therefore represent a handicap and only individuals
in prime health could afford to produce elaborate colourful ornaments. Although further testing is needed, this ‘carotenoid
maintenance handicap’ hypothesis may offer a new insight into the physiological aspects of the relationship between carotenoid
function, immunity and ornamentation. 相似文献
13.
为了解稀土元素的水生生物效应,通过小球藻的培养试验,研究了若干轻稀土元素镧(La)、铈(Ce)、镨(Pr)、钕(Nd)及其混合物对椭圆小球藻(chlorellaellipsoidea)的生理影响。结果显示,低浓度(2~10mg/L)稀土元素在短期内(1~3d)对小球藻叶绿素(a)含量的增长有轻微的刺激促进作用,但随着处理浓度的提高和时间的延长,小球藻叶绿 素(a)含量的增长明显受到抑制,当稀土浓度≥100gm/L时,其叶绿素(a)含量基本处于负增长,小球藻生长停滞,趋于死亡,此时其细胞亚显微结构遭到破坏,尤以叶绿体结构的变化最为明显。4种稀士元素及其混合物对小球藻的毒性尚属中等。 相似文献
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At a very early age several mammals establish a first dominance hierarchy, which often persists into adulthood. Social wasps offer an excellent opportunity to study such a phenomenon in insects. Indeed, foundresses of several paper wasps meet in clusters to hibernate from September to March. In spring, wasps found new associative nests where linear hierarchies occur. In the first phase of hibernation, clustering Polistes dominulus wasps show most of the social interactions occurring on the nest 6 months later. At the emergence from diapause, some females already show some behavioral and physiological traits typical of dominant individuals. Here, we investigated the significance of the interactions in the autumnal clusters. We demonstrated that in a given pair, it is more likely that the dominant wasp in autumn becomes the alpha female in spring after the nest foundation phase occurred. Moreover, we showed that dominant females in clusters have both larger body size and ovaries. As ovarian development mainly depends on the social context, our findings seem to indicate that social factors affect the tendency to dominate in aggregations. Furthermore, we suggest that some females may reinforce their physiological status by dominating in clusters, thus increasing the probability to become dominant in spring. 相似文献
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A2O工艺活性污泥中可培养丝状细菌的多样性 总被引:3,自引:2,他引:1
活性污泥法是应用最广泛的污水处理方法之一,但是由于丝状菌过度繁殖而引发的污泥膨胀是制约其发展的重大难题.本研究从A2O工艺城市污水处理系统的膨胀期活性污泥中分离培养出17株丝状细菌.对各菌株进行了16S rDNA测序和系统发育树分析,结果表明,这些分离的可培养丝状细菌均属于链霉菌属;利用rep-PCR指纹图谱技术进一步分析了所得菌种属内多样性,显示出活性污泥中链霉菌存在丰富的多样性.由于这些可培养丝状细菌与引起污泥膨胀的优势丝状菌(微丝菌)生理特征差别较大,不会在污水处理系统中过度繁殖,本研究向活性污泥中投加一定量的链霉菌分离菌株,发现部分菌株对污泥的沉降性能有明显改善作用,为污泥膨胀的防控提供了新的思路. 相似文献
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Out of three perceptual characteristics of the colour of any substance, the hue depends mostly on the spectral properties
of a substance, while the brightness and saturation depend also on the concentration of a substance and its thickness. Here,
we report that evident change of the hue of the colour (i.e., from green to red) is due to a change in concentration or the
thickness of a layer in some exceptional substances such as pumpkin seed oil or an aqueous solution of bromophenol blue. In
some regions of Central Europe, salad dressing is made preferably with the pumpkin seed oil, which has a strong characteristic
nut-like taste and remarkable properties of the colour: it appears red in a bottle, but green when served as a salad dressing.
The colour of the pumpkin seed oil was previously described as brownish yellow, dark green, dark green to red ochre or dark
reddish brown to light yellow green. We elucidated the physicochemical and physiological basis of such dichromatism by Beer-Lambert
law and by the characteristics of human colour perception. Our concept was corroborated by the outcome of calculations of
colour from spectral properties using colour matching functions. We found that dichromatism is observed if the absorption
spectrum of any substance has at least two local minima: one wide but shallow and one narrow but deep local minimum. 相似文献
18.
Dietrich von Holst Hans Hutzelmeyer Paul Kaetzke Martin Khaschei Ronald Schönheiter 《Die Naturwissenschaften》1999,86(8):388-393
Wild rabbits of the two sexes have separate linear rank orders, which are established and maintained by intensive fights.
The social rank of individuals strongly influence their fitness: males and females that gain a high social rank, at least
at the outset of their second breeding season, have a much higher lifetime fitness than subordinate individuals. This is because
of two separate factors: a much higher fecundity and annual reproductive success and a 50% longer reproductive life span.
These results are in contrast to the view in evolutionary biology that current reproduction can be increased only at the expense
of future survival and/or fecundity. These concepts entail higher physiological costs in high-ranking mammals, which is not
supported by our data: In wild rabbits the physiological costs of social positions are caused predominantly by differential
psychosocial stress responses that are much lower in high-ranking than in low-ranking individuals.
Received: 23 February 1999 / Accepted: 17 March 1999 相似文献
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运行负荷对酶制剂废水厌氧颗粒污泥形成的影响 总被引:8,自引:0,他引:8
通过逐步提高污泥负荷和一步提高污泥负荷2种方法,研究了UASB反应器中运行负荷对酶制剂废水厌氧颗粒污泥形成的影响.结果表明,逐步提高污泥负荷,有利于颗粒污泥的形成.对酶制剂废水厌氧处理而言,在一定程度上,脱氢酶活性的变化可以反映出处理体系中微生物活性的变化,辅酶F420含量变化可定性地判断污泥的产甲烷活性.同时,还从运行良好的反应器中分离到1株优势产甲烷细菌M3菌,依据其形态和生理生化特征,将该菌鉴定为甲烷球形菌属(Methanosphaera sp.). 相似文献