金叶复叶槭两种接穗嫁接效果分析

以金叶复叶槭双芽和四芽做接穗进行嫁接试验,发现采用双芽接穗比四芽接穗嫁接成活率高,生长量大,而且能极大地节约生产成本。     

旱坡地不同植苗处理对澳洲坚果定植成活率的影响

为解决贵州南亚热区冬春季干旱澳洲坚果植苗成活率低、种苗浪费严重、建园成本高等问题,以澳洲坚果Hinde(H2)嫁接苗为试验材料,采用田间试验方法研究了植苗时间、植苗方法和苗木类型对澳洲坚果植苗成活率的影响。结果表明:用2年生营养袋苗于9月采用树盘作集水盘浇定根水加覆盖地膜方法植苗,苗木成活率可达94%以上。该方法建园植苗成活率高,可有效降低新建园生产成本,提高嫁接苗利用率。     

西宁地区智能温室“宁杞7号”硬枝扦插技术研究

本文采用不同扦插基质、不同植物生长调节剂及同一植物生长调节剂-ABT的不同浸泡时间,观察宁杞7号硬枝扦插成活率的影响,结果表明以上层东北泥炭+下层净河沙=2∶1的扦插基质生根效果最好,成活率达86.7%。在不同植物生长调节剂与浸泡时间对插穗生根效果的影响中,以ABT生根粉生根效果较好,浸泡时间宜采用4-5h,成活率分别达88.3%和81.7%。     

大通地区金叶垂榆引种试验

目前城镇绿化树种单一,彩叶绿化乔木树种成为城乡绿化中的点缀佳品,大通地区引种金叶垂榆可为城镇绿化苗木增加了一个新品种,本文介绍了大通引种的金叶垂榆的物候期、生长情况和成活率。     

Assessment of the performance of Pacific oyster (Crassostrea gigas) larvae fed with fresh and preserved Pavlova lutheri concentrates

The Prymnesiophycea Pavlova lutheriwas produced using a traditional technique (batch mode in carboys) and by an innovative technique (semi-continuous mode in alveolarphotobioreactor). Two experimental feedingtrials were carried out with Pacific oyster(Crassostrea gigas) larvae with freshand preserved (4 °C and 1 °C)P. lutheri concentrates used inmonospecific and bispecific diets, incombination with fresh Chaetoceroscalcitrans forma pumilum. Nodifferences in terms of gross composition andlarval performance were noticed between thefresh algae biomass produced by the twotechniques. The low temperatures allowedpreservation of the nutritionalcharacteristics of the P. lutheri freshculture for the time period considered (27days). The P. lutheri concentratespreserved at 4 °C or 1 °C didnot differ substantially in terms ofnutritional value. Larvae fed a monospecificdiet of P. lutheri, both fresh andpreserved, exhibited a modest growth rate (<2.1 µm day^–1), in some cases notsignificantly different from that observed inthe unfed larvae (the control), and a lowsurvival rate. In contrast, when Chaetoceros calcitrans forma pumilumwas used as a monospecific diet, good growthperformance (>4.5 µm day^–1) and ahigh survival rate (>86%) were observed inlarvae. A substitution of 50% (trial 1) or80% (trial 2) of fresh C. calcitransforma pumilum with the preserved P. lutheri concentrates did not adverselyaffect growth rate or survival of C.gigas larvae.     

Death from anthropogenic causes is partially compensatory in recovering wolf populations

There is substantial interest in how mortality rates affect animal populations, but mechanisms explaining when and under what circumstances particular causes of death incur demographic responses are far from clear. In theory, small or expanding populations should experience additive mortality from anthropogenic causes of death, but whether such effects are homogenous across a population or expressed only in certain high-risk individuals is open for debate. We used competing risks models to analyze mortality patterns among radio-collared wolves (Canis lupus, n = 711) from three populations in northwestern United States (1982-2004), and evaluated the degree to which anthropogenic mortality was additive vs. compensatory to natural demographic processes. Almost 80% (n = 320) of wolves dying of known fates were killed by anthropogenic causes (legal control, illegal killing, harvest in Canada, vehicle collision), and additive effects of anthropogenic mortality were most pronounced in northwestern Montana where wolf exposure to humans and livestock was high compared to either the Greater Yellowstone Area or central Idaho, where anthropogenic risk was lower. In contrast, risk from natural hazards was lower in northwestern Montana than in the other areas, implying some degree of compensatory mortality from anthropogenic risk. Animals recruited to the study following human-wolf conflict had markedly higher anthropogenic risk than those recruited for standard monitoring purposes, and juvenile wolves as well as dispersers, succumbed to higher anthropogenic risk. Multivariate models revealed that increasing wolf population density promoted higher anthropogenic risk and reduced natural risk, indicating that partially-compensatory effects of anthropogenic mortality actually became increasingly additive with population density. The observed compensatory mortality and hazard heterogeneity in our study implies that demographic responses to mortality risk may be complex and more subtle than previously thought; the density-dependent effect of anthropogenic mortality portends a stabilizing influence of humans on recovering wolf populations. We conclude that future assessment of the role of anthropogenic mortality should include individual-based hazard estimation as a complement to traditional population-level approaches.     

Quantitative PCR assays to enumerate Rhizobium leguminosarum strains in soil also target non viable cells and overestimate those detected by the plant infection method

The plant infection method is commonly used to estimate the Most Probable Number (MPN) of soil rhizobia. Here, a qPCR method was set-up and validated with newly developed ANU (strain specific) and RHIZ (more general) primers to quantify the specific Rhizobium leguminosarum bv. trifolii ANU843 strain or general R. leguminosarum strains. Detection limits of qPCR protocols in soil were 1.2 × 10⁴ (ANU) and 4.2 × 10³ (RHIZ) cells per g soil. The qPCR assay appears robust and accurate in freshly inoculated soils but overestimated MPN for indigenous soil rhizobia. An incubation experiment showed that qPCR detected added DNA or non viable cells in soils up to 5 months after addition and incubation at 20 °C in moist conditions.     

农村留守妇女的现状·成因与干预策略研究

研究了农村留守妇女现阶段的生存现状及其产生的因素,并且针对这些现状提出切实可行的干预措施.     

我国经济林林地稳定性研究

利用我国16个省市的最近两期森林资源连清固定样地数据，计算和比较经济林和非经济林的保存率，平均年龄，期望寿命等，对我国经济林的林地稳定性，通过定量研究，最后得出我国经济林林地稳定性明显不如非经济林林地稳定性的结论。     

Facilitating the evolution of resistance to avian malaria in Hawaiian birds

Research has shown that avian malaria plays an important role in limiting the distribution and population sizes of many Hawaiian birds, and that projected climate change is likely to eliminate most disease-free habitat in Hawai’i in the next century. I used a modeling approach, parameterized with demographic data from the literature and the field, to examine alternate management scenarios for the conservation of native Hawaiian birds. I examined the feasibility of using management in the form of rodent control to facilitate the evolution of resistance to malaria by increasing the survival and reproduction of native birds. Analysis of demographic data from seven native species, Akepa (Loxops coccineus), ‘Akohekohe (Palmeria dolei), Elepaio (Chasiempis sandwichensis), Hawai’i’amakihi (Hemignathus virens), Hawai’i creeper (Oreomystis mana), Omao (Myadestes obscurus), and Palila (Loxioides bailleui), suggest that differences in life history cause some species to be more susceptible to local extinctions from the transmission of malaria. Modeling results demonstrated that rodent control at middle, but not high, elevations can facilitate the evolution of resistance to malaria in several species of Hawaiian birds. Advocating a management approach that encourages evolutionary change in endangered species contrasts with the traditional conservation paradigm but it may be the best strategy to reduce the impacts of one of the multiple stressors that have devastated the native bird community of Hawai’i.