三疣梭子蟹早期发育阶段最佳饵料投喂策略及投喂密度探讨

三疣梭子蟹是大型可食经济蟹类,具有很高的商业价值。为发展三疣梭子蟹育苗技术,试验对其早期发育阶段的饵料选择、投喂策略及最佳捕食密度进行了探讨。实验设置小球藻组、扁藻组、小球藻与扁藻混合组、轮虫组(加小球藻50×104个/ml)和卤虫组(加扁藻8×104个/ml)5个因素,分别设4、4、4、6和6个梯度。结果表明,小球藻浓度50×104个/ml或扁藻浓度8×104个/ml或小球藻(25~40×104个/ml)+扁藻(2.5~4×104个/ml)可使Ⅰ期溞状幼体(Z1)存活较长时间,但仅投喂单胞藻类不能使Z1正常变态;自Z1开始投喂轮虫可使幼体正常发育至Ⅲ期溞状幼体(Z3),以后幼体发育迟缓,出现Ⅲ期、Ⅳ期溞状幼体(Z4)和大眼幼体(M)同时存在的现象。Z1对轮虫的最佳捕食密度为5个/幼体、Ⅱ期溞状幼体(Z2)为10个/幼体,存活率可分别达到95.7%和94%;从Z3开始应该投喂卤虫无节幼体,捕食密度为10个/幼体,存活率达到最高值为84.5%。从Z4开始投喂卤虫成体,Z4、M和Ⅰ期幼蟹(C)的最佳捕食密度为10个/幼体,存活率分别为90%、85.7%和82.9%。因此,三疣梭子蟹Z1和Z2应该投喂轮虫,最佳捕食密度分别为5个/幼体和10个/幼体;Z3开始投喂卤虫无节幼体,最佳捕食密度为10个/幼体。Z4开始投喂卤虫成体,最佳捕食密度为10个/幼体。同时,育苗水体中添加一定量的单胞藻类。     

STAT6介导的巨噬细胞极化对布鲁氏菌胞内存活的影响

旨在探讨STAT6介导的巨噬细胞极化对布鲁氏菌胞内生存的影响。本研究采用布鲁氏菌光滑株S2308（S2308）和粗糙型疫苗株RB51（RB51）侵染巨噬细胞。利用qRT-PCR检测M1型巨噬细胞标志因子p65、NOS2和IL-1β,M2型巨噬细胞标志因子STAT6、ARG1、IL-10的mRNA表达水平;流式细胞术检测M1型标记分子CD86和M2型标记分子CD206的表达;Western blot检测p-STAT6蛋白及抑制剂AS对蛋白的抑制作用;ELISA检测M1型细胞因子TNF-α、IL-12和M2型细胞因子IL-4、IL-10的表达量;最后对胞内菌落进行CFU计数。qRT-PCR结果显示,在感染8、12 h时可显著诱导M1型因子mRNA转录表达,72 h时低表达,而M2型因子在72 h时高表达;流式细胞术结果显示,S2308感染12 h可显著诱导CD86的表达,感染72 h可显著诱导CD206的表达,但RB51对二者无影响;Western blot结果显示,S2308菌株在感染72 h时激活STAT6信号通路,而RB51几乎不激活该通路,抑制剂AS在2 μmol·L^-1浓度时抑制效果最佳;ELISA结果显示,AS抑制剂可显著抑制IL-4、IL-10的释放,并促进TNF-α、IL-12的释放;CFU计数结果显示,S2308组的胞内菌呈先降低后显著上升趋势,加入AS抑制剂后可显著抑制布鲁氏菌胞内复制。布鲁氏菌S2308在感染后期能够通过STAT6诱导M1型巨噬细胞向M2型转化,并促进Th2型细胞因子的释放,从而有利于布鲁氏菌的胞内生存。而RB51几乎不激活该通路,不影响胞内生存。     

乌饭树组织培养移栽技术研究

根据乌饭树喜酸、喜湿的生物学特性,研究了试管苗移栽前后的一系列配套技术,摸索出最佳移栽程序,移栽成活率达90%。     

GGR6号植物生长调节剂对华北落叶松造林的影响及作用机理

造林前用双吉尔—GGR6号植物生长调节剂对华北落叶松苗进行浸根处理，可提高造林成活率和林木生长量。其作用机理在于调节了苗木内源激素的含量，提高了苗木体内酶的活性，增强了苗木细胞新陈代谢的能力。     

抗风耐盐常绿树种弗吉尼亚栎引种初步研究

引进美国弗吉尼亚栎在浙江、上海、江苏三省市海涂和内陆多个地点试种3～4 a,均能正常生长,在杭州湾滨海盐土上生长良好.弗吉尼亚栎苗缺乏发达的侧根和须根,不易移植成活,采用容器育苗和带土大苗造林可显著提高造林成活率和生长量.     

棕榈藤组培苗移植技术研究

本文研究了黄藤、短叶省藤、单叶省藤、白藤和异株藤组培苗的移植技术。结果显示：试管苗的质量是移植成活与否的关键，适宜的组培苗移植规格为：苗高大于４．０ｃｍ根长大于４．０ｃｍ，带须根；珍珠岩为最优移植介质，移植组培苗的根系生长量大、净 条烽多、成活率最高，分别达２６．１ｃｍ／株、０．８条／株、９５．０％；泥炭土和细沙中选介质，移植成活率〉９０％；最佳的练苗介质配比为４０％泥炭土＋６０％黄心土，移植成活     

甜大节竹丰产栽培试验研究

设计甜大节竹不同时间、不同材料育苗试验和不同造林密度(间种农作物)对比试验研究,经过近8年试验观测,结果是用截杆留鞭育苗,原产地成活率83.3%,引种育苗试验成活率64.2%;采用3m×3m造林密度,栽竹2a,出笋率90.4%,栽竹5a,鲜笋产量365.6kg/667m2。     

Performance of ponderosa pine seedlings under four herbicide regimes in northeast Oregon

The herbicide, hexazinone, was applied four ways over ponderosa pine, 2–0 seedlings planted in northeast Oregon. The four treatments were two broadcast applications, a single broadcast application, a large spot application, and a small spot application. Seedling survival and growth were monitored for five growing seasons. Results indicate that survival more than doubled with either large or small spot applications compared to no application, and either one or two broadcast applications can increase survival an additional 30% over spot applications. Differences in stem volume were substantial, with two broadcast applications yielding more than twice the volume of a single broadcast treatment and more than five times the volume of seedlings treated with spot applications. Trees in small spots were still three times bigger than surviving seedlings in the control. These results are consistent with the concept of competition threshold. Management implications were considered in terms of cost of established seedlings. Although broadcast applications cost more per acre than spot applications, gains in seedling survival, growth and quality offset the additional cost and translate into lower established seedling costs. The cost effectiveness of broadcast applications also may be seen in the elimination of replanting or in-planting requirements and increases in long-term growth potential of the established trees.     

Afforestation trials with Prosopis chilensis (Mol.) Stuntz and Prosopis flexuosa D.C. in the Dry Chaco, Argentina

In implantation trials carried out with Prosopis chilensis and Prosopis flexuosa, the following variables were considered: implantation time (December and March), implantation technique (direct seeding and seedling transplantation) and age of the seedlings at the time of transplantation (60, 105 and 150 days). Survival was evaluated for more than 9 months after implantation and trials were repeated in 3 consecutive years.

Results from both species were similar and they show that survival after transplantation was higher (60–80%) than from direct seeding (35–45%). Survival from transplantation was independent of the size and age of the seedlings and it was less affected by climatic conditions than direct field sowing. Survival from direct seeding was higher in March than in December. The best time for either implantation alternative would be the end of the summer or beginning of fall, when climatic conditions increase the probability of seedling survival.     

进城大树成活率低的原因分析及对策研究

大树引入城市是改变城市生态环境、提高城市绿化绿地质量、生态效益和景观的有效途径。本文分析了进城大树成活率低的原因，提出了提高大树成活率的对策。