渭北旱塬苹果园土壤深层干燥化与硝酸盐累积

以渭北旱塬的苹果园为研究对象,对5～34龄苹果园土壤剖面水分含量分布与硝酸盐累积状况进行研究．结果发现,旱地苹果园的高投入与高产出经营方式不但导致了土壤深层干燥化,而且土壤深层累积了大量的硝态氮,累积层在40～260cm土层,最高含量达403．4mg·kg^-1．由于连续施氮肥,这些氮素被再利用的可能性很小,存在土体中的硝态氮会造成潜在的环境问题．由于土壤深层水对干旱的调节作用减弱或丧失,导致苹果产量受控于当季节降水．因此,应当控制苹果园施氮量,避免氮素的大量累积,并采取措施改善果园水分状况。     

海月水母的生殖

海月水母 Aurelia aurita(Linne,1758) 又称水水母。分布几乎遍及世界,主要在暖海和温带海区。我国大连、烟台、青岛等地沿海均有分布。海月水母为雌雄异体,4个褐色的马蹄形生殖腺位于胃囊的底部(图1,本文照片均见封三)在生殖季节(大连在7月中、下旬;烟台为8月上、中旬),精子或卵由生殖腺排出。大多数精子在口腕基沟区被运送至口腕末端,形成粘液     

环境因子对海月水母螅状体存活与繁殖的影响

以我国黄渤海主要致灾大型水母海月水母的螅状体为实验材料,采用实验生态学方法研究了温度、盐度、光照强度、饵料量对其存活与繁殖的影响。结果表明,在0—25℃范围内,螅状体40 d的成活率均为100%,螅状体相对繁殖速度随温度的升高而增加;盐度在15—40范围内,螅状体40 d的成活率均为100%,盐度22.5组的螅状体相对繁殖速度最高,但盐度对螅状体种群数量影响不显著;螅状体相对繁殖速度随光照强度的增加而下降,黑暗条件有利于海月水母螅状体个体数量增加;螅状体相对繁殖速度随饵料量的增加而增加。研究结果说明海月水母螅状体对环境具有较强的适应性,水温升高、饵料量增加可导致海月水母螅状体种群数量快速增加。     

海月水母无性生殖的影响因子

海月水母是我国黄渤海近岸海域的常见水母种类,近年来海月水母的暴发性增殖已经成为一种近海生态灾害。论文综述了海月水母无性生殖过程的主要类型,其中出芽生殖和横裂生殖是海月水母无性生殖的主要方式。并对影响海月水母无性生殖的主要因子进行了分析和总结,指出现有研究中存在的问题,为进一步开展海月水母无性生殖机制研究提供参考。     

环境因子对草菇生长发育影响的灰色综合评判

本文运用灰色系统理论,进行了环境因子对草菇生长发育的影响的灰色关联评判．结果表明：以A_2B_2C_2D_1E_1,A_4B_1C_2D_2E_1两个处理组合为最佳处理组合,草菇栽培适宜条件为废棉,pH值8.0～8.5,CO_2浓度＜0.2%等．     

温度对海月水母浮浪幼虫的影响

海月水母是黄渤海沿岸海域的爆发水母之一, 具有复杂的生活史, 目前关于其浮浪幼虫生活史阶段的研究相对较少。研究了24 ℃(夏末)和19 ℃(秋初)两种温度对海月水母浮浪幼虫的存活时间、附着和形态的影响。研究结果表明: (1)两种温度条件下海月水母的浮浪幼虫的最大浮游存活时间为21-28 天。(2)温度对海月水母浮浪幼虫的死亡率有显著影响(F = 4.238; P < 0.05), 24 ℃下的死亡率显著高于19 ℃。(3)两种温度条件下海月水母浮浪幼虫的附着率无显著差异(P > 0.05)。(4)温度对海月水母浮浪幼虫的长度有显著影响(F = 7.153; P < 0.05), 对海月水母浮浪幼虫的宽度影响不显著(P > 0.05)。上述研究结果为海月水母早期浮浪幼虫生活史阶段种群动态研究提供了重要参考。     

环境因子对药用植物药材形成的影响研究进展

药用植物是中药资源库的重要组成部分,药用植物中有效成分含量的高低是评鉴药材质量优劣的重要标准之一,而环境因子在药材形成过程中起着决定性作用,适宜的生长环境能促进药材中有效成分的合成与积累,从而提高药材质量。本文就近10年来国内外对光照、水分、温度等环境因子对药用植物质量影响的研究文献进行综述,为药用植物优质药源基地建设关键技术研究提供思路。     

温度对海月水母螅状体生长及繁殖的影响

采用了实验生态学方法,研究温度对海月水母螅状体生长及繁殖的影响。实验设6个温度梯度(12, 15, 18, 21, 24, 27℃),共持续56d。测定了螅状体的柄径生长,繁殖数量;观察了螅状体的无性繁殖方式;分析了温度影响下的螅状体的能量分配及繁殖策略。结果表明,温度显著影响螅状体的生长及繁殖,在较高温度组,匍匐茎生殖是螅状体无性繁殖的主要方式,随着温度降低,出芽生殖比例增加。较高温度组螅状体繁殖速率较快,新生螅状体个体较小,分布较分散;而较低温度组,新生螅状体个体较大,数量较少,均较紧密的分布在亲代螅状体周围。在培养56d的周期内,除27℃处理组外,其他各处理组螅状体柄径均有所增加,但其增加的速率随着温度的升高而降低。而27℃处理组,螅状体整体状态不好,基本不摄食,培养35d时全部死亡。综上,较低温度条件下,螅状体倾向于选择增加自身个体大小以应对不良环境,而当环境条件适宜时,螅状体倾向于选择通过无性繁殖产生更多子代的方式以扩大种群数量。温度显著影响螅状体的繁殖策略,进而显著影响螅状体的种群数量。     

环境因子对植物萜类化合物生物合成的影响研究进展

植物在应对不同环境胁迫时会做出不同的应对措施,其中一种常见的方式是产生次生代谢产物。萜类化合物为植物次生代谢产物中种类最多、结构最复杂的一类化合物,几乎存在于所有植物中,发挥着重要的生物功能,很多具有显著的药理活性,如免疫调节、抗肿瘤、降血脂、保肝等。该文对近年来国内外有关环境温度、紫外线辐射、光照、干旱、臭氧及植物生长发育阶段等环境因素对植物萜类化合物合成影响的研究进展进行综述,探究植物萜类化合物受环境因子影响产生应激反应的一般性规律。     

大型水母幼体生长的影响因子研究进展

21世纪以来,中国东、黄海,韩国西海岸以及日本海连年发生大型水母暴发现象,对海洋渔业的生产活动以及海洋生态系统带来巨大的影响。水母暴发形成机制非常复杂,解释其发生机理并有效预报是目前急待解决的问题。大型水母的生活史中有明显的世代交替现象,受精卵,浮浪幼虫,螅状体,足囊,横裂体到碟状体的幼体发育阶段属无性世代,幼蜇发育到成蜇阶段属有性世代。在早期生活史中,螅状体的足囊繁殖与横裂生殖是大型水母无性繁殖的重要方式,对其成体的数量形成至关重要。综述了国内外有关温度、盐度、光以及营养条件对大型水母早期发育阶段的影响研究进展,研究表明温度是影响螅状体发育以及足囊繁殖和横裂生殖的最主要的环境因子;盐度、光和营养条件在适温范围内,均对螅状体和横裂生殖有一定的影响,其上下限随水母种类和发育阶段有所变化。展望了大型水母早期幼体研究的发展趋势,如环境因子对不同种类的大型水母幼体生长机理的影响、多个环境因子对幼体的综合作用、动态的环境因子与大型水母幼体之间的关系等。     

Maternal effects on offspring growth and development depend on environmental quality in the frogBombina orientalis

Summary Differences in maternal investment and initial offspring size can have important consequences for offspring growth and development. To examine the effects of initial size variability in the frogBombina orientalis, we reared larvae (N=360) in one of two treatments representing different levels of environmental quality. We used snout-vent length at the feeding stage (stage 25, Gosner 1960) as a measure of maternal investment. In a “low quality” treatment, larvae were reared with two conspecific tadpoles and food was limited, whereas in a “high quality” treatment, larvae were reared individually and were fed ad libitum. Among tadpoles reared in the low quality treatment, individuals that were initially small had smaller body sizes through metamorphosis and longer larval periods than individuals that were initially large. Among tadpoles reared in the high quality treatment, initial size had only a weak influence on later larval size, and did not significantly affect metamorphic size of the duration of the larval period. This interaction between maternal investment and rearing conditions suggests that production of initially small offspring could be advantageous if these offspring develop in relatively benign environments, but disadvantageous if environments are more severe. These findings are discussed in light of previous studies that have demonstrated such interactions in organisms with complex life cycles.     

重金属在海草中累积及其对海草生长的影响

海草是生长在近海浅水中的单子叶高等植物,对维持近海生态平衡起着重要作用,而重金属污染对海草有重要影响.研究重金属对海草的影响过程与机理对海洋生态环境保护具有重要意义.本文总结了国内外近年来在海草受重金属污染影响方面的研究进展,包括海草重金属累积的特征及其主要影响因素,重金属对海草生理生态特别是光合效率的影响,以及海草对重金属胁迫的内在生理生化适应机制等.提出了今后的研究方向,通过同位素示踪的方法比较海草通过叶片吸收与通过根吸收重金属的差异,进行多种重金属在毒性协同和拮抗方面的研究,比较重金属对海草急性毒性和慢性毒性的差异,加强重金属对海草毒性机理的研究等.     

Effects of environmental factors on development of wood

This research tested the hypothesis that environmental factors (light, water, and nutrient levels) affect wood development. Specimens were placed in treatments of low, medium, or high levels of light, water, nitrogen, or phosphorus for one year. Control plants received medium levels of all factors, while experimental plants received medium levels of all factors except the experimental factor; for example, "high light" treatment consisted of high light but medium levels of water, nitrogen, and phosphorus. Some character changes seen in Cereus peruvianus were a reduction in mean vessel diameter and shoot elongation as a result of low nitrogen and low phosphorus treatments and a reduction in mean vessel density due to low light; high water induced broader vessels and greater shoot elongation. In Cereus tetragonus, low water treatment caused a reduction in mean vessel diameter, and high nitrogen decreased the amount of wood produced. Whereas all characters studied showed a significant correlation with at least one treatment in one species, few characters responded similarly between species. Estimated specific conductivity of wood could be altered by treatments affecting either vessel density or vessel diameter strongly or by treatments affecting both diameter and density weakly. Under the conditions tested, wood structure was stable but estimated conducting capacity was more flexible.     

Influence of environmental factors on the development of the valve in diatoms

Summary The species-specific form and structure of the diatom shell is variable within a given genetical reaction-norm, depending on the dynamic interrelation between cell and environment. The appearing modifications—based on quantitative disarrangement of construction-units as well as on a change in size and outline—can be understood as the morphological expression of a changed metabolism which has become necessary for adaption to adverse conditions. The diatoms react very sensitively, especially to the salinity factor, whereby actually two alternatives of adaption occur: a vegetative, in building resting spores (f.i., Navicula cuspidata) and a generative (f.i., Anomoeoneis sphaerophora, Surirella peisonis).Teratologies have been found in totally unbalanced surroundings (especially under conditions of ion unbalance), where the usually symmetrical forms have lost the coordination of the construction-units to each other (f.i., Surirella peisonis). They supply good criteria in clarifying the problems concerning pattern development.Dedicated to Univ.-Prof. Dr. H. A. v.Stosch's 70th Birthday.     

环境因素对湖泊高等水生植物生长及分布的影响

综述了水质、底质、周丛生物,浮游生物等对湖泊水生高等植物生长的影响,指出:水生高等植物的恢复是湖泊生态功能恢复的关键;水生高等植物恢复,应在营造其合适生境的基础上,以自然恢复为主,人工恢复应遵循自然规律,优化群落结构;草食性鱼类对湖泊水生高等植物负面影响较大,应注意控制.     

The effects of environmental factors on growth and the chemical and biochemical composition of marine diatoms. I. Light and temperature effects

Temperature and light interact to modify the chemical and biochemical composition of a nitrogen-limited marine diatom, Thalassiosira allenii Takano, grown at a constant dilution rate in continuous culture and under a light:dark cycle.The percent of the total ¹⁴C incorporated into protein, polysaccharide and lipid, the N/C ratio and the C/cell varied with temperature in a markedly non-linear manner. The N/cell was negatively correlated to temperature. The Chl $\text{a}\text{C}$ ratio was positively correlated with temperature under saturating light and non-saturating light for temperatures > 25 °C, but was constant under non-saturating light conditions for temperatures < 25 °C.Productivity index (PI) was negatively correlated to temperature under saturating light conditions, but did not vary under low light. In each case, the variation in PI with temperature was governed by the variation in Chl $\text{a}\text{C}$.The dark carbon loss rate was exponentially related to temperature and independent of light. Variation in the percent of the total ¹⁴C incorporated into protein and polysaccharide, the $\text{N}\text{C}$ ratio and C/cell was primarily due to the effects of N-limitation < 20 °C and primarily due to the effects of temperature > 20 °C. Variation in N/cell was primarily due to the effects of temperature over the entire range of temperature studied. Variation in Chl $\text{a}\text{C}$ was caused by the interaction of temperature and light effects.In most cases, temperature and nutrient effects interacted to govern how a particular parameter varied with temperature while light affected the range of values over which the parameter varied.The percent of the total ¹⁴C incorporated into protein exhibited a significant linear relationship with $\text{N}\text{C}$.The dark carbon loss rate, $\text{N}\text{C}$ ratio and Chl $\text{a}\text{C}$ ratio data were used to test the applicability of a model for the physiological adaptation of unicellular algae. The model, with parameters derived from a non-linear least-squares fit of the dark carbon loss rate data, adequately described the $\text{N}\text{C}$ ratio between 15 and 25 °C at 290 and 137 μE · m^?2 · s^?1, but failed to describe the data at 28 °C and at 48 μE · m^?2 · s^?1. The Chl $\text{a}\text{C}$ ratio was adequately described by the model under all light and temperature conditions.     

Pin1促进肿瘤发展相关机制的研究进展

脯氨酰顺反异构酶1(peptidyl-prolyl cis-trans isomerase NIMA-interacting 1,Pin1)为细胞内主要起信号传导作用的小分子蛋白。Pin1在肿瘤中的异常表达和信号调控促进肿瘤的发展,包括诱导耐药、辅助致肿瘤性病毒感染、参与肿瘤的缺氧代谢和其它信号调控等。本文对于Pin1的促肿瘤发展特点进行简要总结。