蔺草开花与温光条件关系的数学分析及模拟模型

本文对蔺草开花与温光条件关系作了分析研究.根据浙江宁波市郊区1992-2000年的农业气候资料的分析计算表明,影响蔺草冈山3号草茎开花率（SFR）的主要气象因子为12月下旬、2月中旬的平均气温,2月下旬的日照时数和3月下旬的雨量.依据春化作用的机理和上述影响因子的分析,得SFR的模拟模型为:SFR=其中∑j相似文献   

The effect of falling height on muscle activity and foot motion during landings

The aims of this study were: (a) to examine the effect of falling height on the kinematics of the tibiotalar, talonavicular and calcaneocuboid joints and (b) to study the influence of falling height on the muscle activity of the leg during landings. Six female gymnasts (height: 1.63±0.04 m, weight: 58.21±3.46 kg) participated in this study. All six gymnasts carried out barefoot landings, falling from 1.0, 1.5 and 2.0 m height onto a mat. Three genlocked digital high speed video cameras (250 Hz) captured the motion of the left shank and foot. Surface electromyography (EMG) was used to measure muscle activity (1000 Hz) from five muscles (gastrocnemius medialis, tibialis anterior, peroneus longus, vastus lateralis and hamstrings) of the left leg. The kinematics of the tibiotalar, talonavicular and calcaneocuboid joints were studied. The lower-leg and the foot were modelled by means of a multi-body system, comprising seven rigid bodies. The falling height does not show any influence on the kinematics neither of the tibiotalar nor of the talonavicular joints during landing. The eversion at the calcaneocuboid joint increases with increasing falling height. When augmenting falling height, the myoelectric activity of the muscles of the lower limb increases as well during the pre-activation phase as during the landing itself. The muscles of the lower extremities are capable of stabilizing the tibiotalar and the talonavicular joints actively, restricting their maximal motion by means of a higher activation before and after touchdown. Maximal eversion at the calcaneocuboid joint increases about 52% when landing from 2.0 m.     

植物生长季退化草毡寒冻雏形土CO2释放特征

对中国科学院海北高寒草甸生态系统定位站地区退化草毡寒冻雏形土CO2释放的全天候连续观测结果表明,退化草毡寒冻雏形土CO2的释放有明显的日变化和季节动态,日最大释放速率出现于12：00-14：00,最小释放速率出现于6：00-8：00;植物生长季的最大振幅为462.49mg·m^-2·h^-1（8月18日）,最小振幅为114.97mg·m^-2·h^-1（5月9日）,CO2释放速率白天大于夜晚。不同物候期CO2释放速率亦不同,草盛期>枯黄期>青期。最大日均值为480.76mg·m^-2·h^-1（8月18日）,最小日均值为140.77mg·m^-2·h^-1（5月9日）。释放速率与气温、地表温度及土壤5cm地温均呈显著或极显著相关关系,表明温度是决定CO2释放速率季节变化的首要因素。     

腾冲热海眼镜泉菌藻席细菌ARDRA指纹图谱分析

对腾冲热海眼镜泉中粉红色丝状菌藻席进行ARDRA指纹图谱分析,获得其细菌多样性的部分信息。直接提取菌藻席总DNA,以之为模板PCR扩增出细菌的16S rDNA,将其克隆、转化进入大肠杆菌,获得120个克隆子。用限制性内切酶(RsaⅠ、HhaⅠ、HapⅡ)筛选出了29个16S rDNA插入片段酶切带型差异明显的克隆,表明眼镜泉菌藻席细菌组成丰富。聚类分析显示这29个克隆聚为A、B两个大类,表明该菌藻席可能主要由两个遗传多样性丰富的分类群组成。     

高寒矮嵩草草甸大气-土壤-植被-动物系统碳素储量及碳素循环

对高寒矮嵩草草甸生态系统中大气 -土壤 -植被 -动物分室碳素储量及碳素循环进行了研究 ,结果表明 ,草毡寒冻雏形土土壤库 0～ 30 cm碳素储量为 2 4 7.30 t C/ hm2 。土壤 CO2 平均释放速率 70 .94± 54.76kg/ (hm2· d) ,年释放量为 6.630 t C/ (hm2·a) ,比退化草地 4.62 0 t C/ (hm2·a)释放量高。植物包括根系总固碳量为 4.648t C/ (hm2· a) ,动物亚系统中 ,藏系绵羊个体同化的碳素为 7.562 kg C/ (hm2· a) (成年羊 ) ,作为畜产品迁出生态系统。生态系统初级生产固碳量占每年土壤 CO2 释放量的 70 .1 6% ,占生长季土壤 CO2 释放量的 96.43% ,退化草地土壤 CO2 释放量比初级生产固碳量要低。认为高寒矮嵩草草甸生态系统土壤是大气温室气体 CO2 的小的排放源。     

Phylogenetic Analysis of Phaeosphaeria Species Using Mating Type Genes and Distribution of Mating Types in Iran

Phaeosphaeria species are pathogenic on wheat, barley and a wide range of wild grasses. To analyze mating type loci of the Phaeosphaeria species and investigate mating type distribution in Iran, we sequenced mating type loci of 273 Phaeosphaeria isolates including 67 isolates obtained from symptomatic leaves and ears of wheat, barley, and wild grasses from two wheat-growing region in Iran as well as 206 isolates from our collection from other regions in Iran which were isolated in our previous studies. Mating type genes phylogeny was successfully used to determine the species identity and relationships among isolates within the Phaeosphaeria spp. complex. In this study, we reported seven new host records for Phaeosphaeria species and the Phaeosphaeria avenaria f. sp. tritici 3 group was first reported from Iran in this study. Mating type distribution among Phaeosphaeria species was determined. Both mating types were present in all sampling regions from Iran. We observed skewed distribution of mating types in one region (Kohgiluyeh va Boyer-Ahmad) and equal distribution in the other region (Bushehr). However, when considering our entire dataset of 273 Iranian Phaeosphaeria isolates, the ratio of mating types was not deviated significantly from 1:1 suggesting possibilities for isolates of opposite mating type to interact and reproduce sexually, although the sexual cycle may infrequently occur in some regions especially when the climatic conditions are unfavorable for teleomorph development.     

植物生长季退化草毡寒冻雏形土CO2释放特征

对中国科学院海北高寒草甸生态系统定位站地区退化草毡寒冻雏形土CO₂释放的全天候连续观测结果表明,退化草毡寒冻雏形土CO₂的释放有明显的日变化和季节动态,日最大释放速率出现于12:00～14:00,最小释放速率出现于6:00～8:00;植物生长季的最大振幅为462.49mg·m^-2·h^-1(8月18日),最小振幅为114.97mg·m^-2·h^-1(5月9日),CO₂释放速率白天大于夜晚.不同物候期CO₂释放速率亦不同,草盛期>枯黄期>返青期.最大日均值为480.76mg·m^-2·h^-1(8月18日),最小日均值为140.77mg·m^-2·h^-1(5月9日).释放速率与气温、地表温度及土壤5cm地温均呈显著或极显著相关关系,表明温度是决定CO₂释放速率季节变化的首要因素.     

草毡寒冻雏形土CO2释放特征

研究了植物生长季节海北高寒草甸生态系统高寒嵩草草甸覆被下草毡寒冻雏形土的 CO2 释放速率。其结果表明 :CO2 释放速率有明显的日变化和季节动态。日最大排放速率多出现在 1 4 :0 0～ 1 6:0 0时 ,最小排放速率在 6:0 0～ 8:0 0时。植物生长季日最大振幅为 797.75mg/m2·h,最小振幅 1 97.33mg/m2·h。CO2 排放白天大于夜晚。不同物候期 CO2 释放速率不同 ,其顺序为草盛期 >枯黄期 >返青期。生长季土壤 CO2 释放速率的范围是 4 41 .72 mg/m2 · h± 1 55.2 9mg/m2· h,最大日均值为 681 .0 6mg/m2 · h( 7月 1 6日 ) ,最低值 1 76.65mg/m2 · h ( 6月 1日 )。退化草地土壤 CO2 释放速率明显低于未退化草地 ,生长季平均日均值低 1 37.4 7mg/m2·h。相关分析表明 :土壤 CO2 排放速率与气温、地表温度、土壤5cm、1 0 cm、1 5cm、2 0 cm、30 cm地温均呈显著和极显著相关关系。温度是影响土壤 CO2 释放速率的主要因子。     

腾冲热海眼镜泉粉红色菌藻席的细菌组成分析

应用免培养法系统研究眼镜泉粉红色菌藻席的细菌组成。经过克隆筛选,测定了23个克隆的16S rDNA插入片段的近全序列。与GenBank的序列进行比对和相似性分析,结果表明,组成该菌藻席的细菌分属于Proteobacteria、Firmicutes、Bacteroidetes、Actinobacter、Deinococcus-thermus、Aquificals 6个类群(phylum),表现出了高度的细菌多样性。结合分析温度相近的5个热泉：Octopus spring、Haegindi and Fluidir spring、Olkelduhals、Grendalur spring中的菌藻席细菌组成,表明生态位相近的不同环境中,其物种组成相近。Aquificales是中性或弱碱性高温热泉菌藻席群落的优势物种。     

Functional structure of algal mat (Cladophora glomerata) in a freshwater in western Poland

GAMs (Generalized Additive Models) present a growth pattern for the common filamentous algae (FA) taxa in freshwater ecosystems in Poland. Tribonema, Ulothrix taxa are an early spring species. In comparison with Rhzioclonium, Cladophora and Oedogonium taxa, the algae Zygnemataceae (e.g. Zygnema, Spirogyra) occurs in waters with lower levels of nutrients, total dissolved substances and electrical conductivity. Cladophora glomerata shows different responses to environmental gradients than C. rivularis, C. fracta. Furthermore, the algae Cladophora glomerata (Chlorophyta, Ulvophyceae) forms a thick monoalgae mat (from the surface to the bottom) in the shallow and eutrophic Lake Oporzynskie in Wielkopolska Region in Poland (Central Europe). Detailed algal mat characteristics, physical and chemical parameters of water, and pigments in thalli were measured vertically (surface, middle, bottom) and spatially (marginal and central part) in the stationary mat phase during maximal algal growth. Temperature, dissolved oxygen and PAR irradiation significantly declined as the depth of the mat increased. Water turbidity was greater in the surface layer than in deeper parts, in contrast to the concentrations of N-NO₃, N-NH₄ and TDS. Pigment content in the cells of C. glomerata, cell lengths and diameters of pyrenoids changed throughout the mat, from top to bottom. The obtained data were used for statistical analyses. In conclusion: dense mats of C. glomerata show a vertical stratification while the mats remain spatially homogenous. Our data suggest that mat structure be considered a biological indicator of freshwater eutrophication.