高粱与旱稻属间杂交部分遗传物质导入的F3及BC1表型鉴定

以高粱（S．bicolor）为母本、旱稻（O．sativa）为父本进行属问杂交，F1出现双亲没有的短芒和黄色柱头新性状，并能在F2、F3及BC 1 稳定遗传。F1在株高、穗长、穗型、分蘖性等性状上仍疯狂分离，并出现父本白色籽粒单株。BC1在株高、分蘖二性状上接近父本，回交效应非常明显，t测定无差异，并出现多子房新性状。高梁与旱稻杂交及回交，能创造变异，产生新性状，对创造矮秆、优质、多子房新种质十分有效。然而，二者杂交后代主体性状仍似母本，只表现父本少数性状。属于部分遗传物质导入。     

辣椒若干性状的相关及通径分析

对辣椒的13个杂种一代及其16个亲本的总产量等16个性状进行分析,结果表明,辣椒的总产量与早期产量及果实胎座宽度呈显著正相关,与干物质含量呈显著负相关;单果重与胎座宽度及果肉厚度呈显著正相关,与单株果数呈显著负相关。株高与播种至花期天数,始花节位与播种至花期天数及维生素C含量与果实长度之间也呈显著正相关;单株果数对总产量的直接影响最大,果实胎座宽度及早期产量也对总产量有明显的直接影响,而其它性状则仅对总产量产生有限的直接影响。     

豫州褐壳蛋鸡各品系主要经济性状间的相关分析

本文用多变量相关分析和通径分析方法，对豫州褐壳蛋鸡５个品系产蛋性能方面的性状进行相关分析，结果表明，将开产日龄，４０周龄平均蛋重和４０周龄产蛋数，作为蛋鸡早期选种指标是适宜的。     

贵州小果油茶种实表型性状多样性分析

为了解贵州小果油茶的自然变异情况,以贵州黎平和榕江的5个居群30个小果油茶优良单株为研究对象,测定并分析果高、果形、高径比、果皮厚度、单个果重、单果中籽粒数、籽粒重和出籽率等8个种实性状,采用多重比较、变异系数、相关性分析、聚类分析和Shannon-Weiner多样性指数等方法,分析小果油茶种实性状的多样性及群体间和群体内的变异特征与变异规律。结果表明:小果油茶不同种实性状的多样性指数为1.014~2.242,种实性状多样性高,在群体间和群体内均存在丰富的变异;经相关分析,小果油茶的果皮厚度与出籽率呈极显著负相关,果高与果径、果形指数、果皮厚度和单果籽粒数呈极显著正相关;表型性状聚类结果与居群分布一致。     

石灰岩地区土壤水分对木豆表型可塑性的影响

研究了土壤相对含水量分别为27．65％,19．47％,12．14％和7．66％水分条件下木豆(Cajannus cajan)幼苗生长和形态的表型可塑性。结果表明：木豆幼苗的根、叶、茎生物量以及株高、冠幅直径都在土壤相对含水量为12．14％的条件下最高;随着土壤含水量的增加,分配到枝和根的生物量随之增加,分配到叶的生物量减少;当土壤相对含水量从7．66％升到12．14％时,须根数目增加,土壤相对含水量再提高时,情况则相反。这些结果说明木豆幼苗的适宜水分生态位是较干旱的土壤环境,木豆幼苗通过器官生物量分配和形态结构调整来适应干旱胁迫。     

Needles in haystacks: Estimating detection probability and occupancy of rare and cryptic snakes

The species most in need of conservation or management are often also the most difficult to monitor, because of their rarity, secretive habits, or both. To combat these challenges, presence/absence (site occupancy) models can be used to track species occupancy at landscape scales. However, quantitative knowledge of detection probability (which is almost always <1) is required to reliably estimate site occupancy. Here, we present a case study that combines detection probabilities and site occupancy modeling to monitor a notoriously secretive guild of animals, North American aquatic snakes. Specifically, we use program PRESENCE to estimate detection probability (p) and probability of site occupancy (ψ) for seven snake species in relationship to site covariates, to understand the proximate and ultimate factors that influence habitat suitability. We were able to estimate p (3–46%) and ψ (12–96%) for each species and calculate the amount of unsuccessful effort necessary to declare absence of each species with statistical confidence (5–63 visits; 150–1890 trap-nights). We documented considerable interspecific variation in p and ψ; one species (Nerodia fasciata) was widespread and highly detectable, while another (Agkistrodon piscivorus) had low detectability despite its wide distribution. Five other species were secretive, or restricted to specific habitat types, or both, illustrating that complex and sometimes counterintuitive relationships exist between capture rate and occupancy. Incorporating p and ψ is essential to the success of large-scale monitoring programs for elusive species.     

Effects of modified Pb-, Zn-, and Cd- availability on the microbial communities and on the degradation of isoproturon in a heavy metal contaminated soil

The effects of modified heavy metal (HM) availability on the microbial community structure and on the microbe-mediated degradation of herbicide isoproturon (IPU) were evaluated in soil with a long-term HM contamination. The fate of ¹⁴C-ring labelled IPU was investigated for over 60 days under controlled microcosm conditions. Phosphate mineral apatite and a water solution of Pb, Zn, and Cd salts were previously homogeneously mixed into the soil material to reduce and to increase the proportion of bioavailable HM, respectively. The availability of Pb, Zn, and Cd was determined by HM fractionation and plant uptake 110 days after the addition of amendments, shortly before IPU addition. Apatite treatment reduced the availability of HM, but did not affect the microbial biomass and the microbial community structure on the genotype level (total soil DNA-RAPD). However, it changed the microbial community structure on the phenotype level, based on the composition of phospholipid fatty acids (PLFA) at the end of the degradation experiment. The degradation of IPU did not change. In contrast to apatite treatment, HM supplementation increased the bioavailability of Pb, Zn and Cd, which resulted in biomass reduction and changes of microbial community structure on the genotypic (total soil DNA-RAPD) and phenotypic (PLFA) level. Increased bioavailability of HM also significantly reduced the rate of IPU degradation and mineralisation. The total mineralisation over a period of 60 days decreased from 12 to 5% of initial ¹⁴C. Increased HM bioavailability did not influence the degradation pathways and kinetics of IPU.     

An evaluation of field and non-invasive genetic methods to estimate brown bear (Ursus arctos) population size

Estimates of population size and density are essential for successful management and conservation of any species. Although there are a variety of methods available for estimating abundance and density of populations, most studies rely on only one estimator and very few studies have compared and critically evaluated the adequacy and the cost of these methods. We used the brown bear (Ursus arctos) in south-central Sweden to compare the performance of three different methods of estimating population size, including methods based on conventional field data as well as on non-invasive genetic data. The method based on observations of females with cubs underestimated the true population size, as the estimates were below the number of unique genotypes determined from faecal data inside the study area. The best traditional method was based on observations of bears from a helicopter. The genetic method using the closed population MARK estimator, as recommended in a previous study, seemed to perform the best. We conclude that approximately 223 (188-282) bears were present in our 7328 km² study area during 2001 and 2002 and suggest that this hunted brown bear population has been relatively stable for about ten years. The non-invasive genetic method was less expensive than the most reliable traditional field method (a CMR method based on observations of bears from a helicopter), and preferable from an ethical point of view. We recommend that future studies using non-invasive genetic methods based on collected faecal samples should aim at collecting 2.5-3 times the number of faecal samples as the “assumed” number of animals.     

瘦肉型生长肥育猪某些血液化学性状与增重的关系

测定了60-75日龄杜洛克×施格杂交1代仔猪9项血液化学性状,估测了血液性状间及其性状与日增重的表型相关。并在此基础上进行通径分析。结果表明:血清Se,Cu,AKP含量与日增重呈显著相关(相关系数分别为0.4757~(**),0.4125~(**),-0.3698~*);AKP,Se,Cu,GSH-PX的含量与日增重通径系数分别为-0.8416,0.5006,0.4904,0.4099,均达显著水平。因而,AKP,Se,Cu,GSH-PX可作为影响瘦肉型生长肥育猪的相对重要性状。     

Response to flooding intensity in Elytrigia repens, E. intermedia (Poaceae: Triticeae) and their hybrid

Response to flooding intensity in three closely related taxa, Elytrigia repens, E. intermedia and their hybrid was studied. Plants were exposed to three intensities of flooding for a 30‐day period. Response to flooding intensity was estimated by measuring dry mass of the following: total biomass, above‐ground living biomass, above‐ground dead biomass, below‐ground biomass, rhizome and root mass and by the allocation of dry mass into rhizomes and root:shoot ratio. Reduction of nearly all the biomass compartments with increasing flooding intensity was observed in the three taxa. All three taxa can thus be regarded as flood‐intolerant. Based on the parameters measured, E. repens is regarded as the relatively most flooding‐tolerant, E. intermedia as the least tolerant, while the hybrid displayed intermediate flooding tolerance. The higher flooding tolerance in E. repens was likely related to its ability to accumulate a sufficient mass of rhizomes before flooding, due to higher regeneration ability. E. repens also displayed the highest phenotypic plasticity, as deduced from the reaction norms constructed for total biomass and rhizome mass of particular clones of the three taxa studied. This indicates that, on the species level, E. repens is better adapted to changing environmental conditions and it can be expected to colonize flooded soils. Both Elytrigia species also occur as weeds: E. intermedia grows in agricultural environments in warm regions, while E. repens infests many different types of habitats. Where they co‐occur, hybridization between them may lead to the enrichment of their gene pools with genes responsible for survival of the parental species under extreme conditions; their weedy potential may thus be enhanced.