台湾中部暖温带阔叶林年轮特征、生长与树龄结构

台湾目前对于阔叶树种的生长轮少有研究,尤其对于天然阔叶林的生长趋势与模型的相关研究更是缺乏,许多资料仍相当不足,有鉴于此,本研究将针对台湾中部地区的典型暖温带阔叶林进行生长轮的研究与探讨。神木溪保护林于2003年已设置完成18个长期观察的森林动态样区,本研究采用第13~18共6个样区内所有胸径大于6 cm之阔叶树,依据林分特征调查结果,钻取大于6 cm胸径林木,钻取高度约在胸径位置,共取得22科33属39种合计448支树芯。年轮分析运用实体显微镜配合CCD拍摄,目视各树种内年轮的变异,并加以分类,作为年轮目视判视与计数年轮的依据,并用Velmax系统量测年轮宽度,应用树冠级模式(CCM)、定期生长量模式(PAI)及混合模式(Mixed)建立各冠层生长趋势,并解析各树种树龄结构,以提供台湾最大面积、分布最广之楠槠及栎林带林分经营之参考。年轮特征上,属于散孔材树种占79%;半环孔材树种占18%;环孔材树种占3%。生长趋势上,所有树种的平均生长速率统计结果为3.53 mm/a。冠层产生垂直层次分化作用明显,显示出其生长的趋势,上主冠层直径增长情形最快,平均生长率为4.47 mm/a;主冠层其次,平均生长率为2.95 mm/a;底冠层速率最慢,平均生长率为2.92 mm/a。PAI模式显示大部分树种的生长趋势是呈现年轮宽度随树龄增加而增加或线性常数的情形。树龄估算以树冠级模式、PAI模式和混合模式3种模式估算,全部平均年龄分别为55、60、59年。混合模式的利用可以降低单独使用树冠级模式或PAI模式的误差率。树龄结构上,依树冠级模式、PAI模式及混合模式龄级分布结果,本样区充满耐阴性树种前生苗与灌木,逐渐形成典型的复层林。树龄出现2种分群,第1种大多为耐阴性树种的小苗,树木建立时间为20世纪后期;第2种在1900年左右形成了1个独立的单峰。年轮不明显区别造成类型分类的困难,轮宽不规则也无法明确定年,PAI模式需要大量的各龄阶树芯数据建立回归模式,所得到的模型才具有足够之代表性,混合模式虽解决了部分树龄推估的误差,但仍有其他问题,因此日后应更进一步进行探讨与分析,方能对森林生态系之永续经营与发展产生一定程度的帮助。本研究提供暖温带阔叶林林分径向生长与树龄结构信息,以供森林收获采伐和森林永续经营参考。      

论多校区大学学生党建工作

近年来,高校多校区办学已成为全国高校普遍的运作方式,这给我国传统的大学运作管理格局带来了许多全新的冲击与挑战,其中,学生党建工作尤为突出。本文通过对现阶段多校区高校党建工作面临的问题与困难展开分析,在此基础上提出了建立健全各类党建制度、充分利用网络资源并在学生公寓开展党建工作等相应对策。     

Hatchery production of Florida red tilapia seed in brackishwater tanks: the influence of broodstock age

Abstract. Production of Florida red tilapia seed (eggs, sacfry and fry) in 34-m² above-ground tanks using recirculated brackishwater (12 ppt) was studied over a 5-month period on Lee Stocking Island (Exuma Cays, Bahamas). Four tanks were stocked with year class 1 (YCI) breeders, while 2 tanks were stocked with year class 2 (YCII) breeders at densities of 200 and 240/tank (5·9 and 7·1/m²), respectively, and at a sex ratio of 3 females to 1 male, beginning in November 1988. Seed production was measured by removing free-swimming fry from tanks and eggs and sacfry from the mouths of brooding females, and assessing the number of each at 15 to 16-day intervals from February to June 1989. Average seed production (seed/m²/day) was significantly higher in YCI (52·3) than in YCII (36·0) broodstock, indicating the advantages of replacing broodstock with yearling breeders each year.     

哈茨木霉对水稻恶苗病菌的拮抗作用

PDA平板拮抗试验表明 ,哈茨木霉对水稻恶苗病菌有强烈的拮抗作用 ,其孢子悬浮液的含孢量为 10⁶～10⁷个 /mL时 ,对恶苗病菌的抑制力达 92.33%。通过哈茨木霉菌液和 3种药剂对水稻恶苗病菌抑制效果的比较 ,哈茨木霉孢子悬浮液含孢量为 10⁷个 /mL与施保克质量浓度 1μg/mL的抑菌效果接近 ,分别为 76.7%、75.4%。显微摄影结果显示 ,哈茨木霉以附着胞附着在恶苗病菌菌丝上 ,然后穿透菌丝在其内生长 ,或与恶苗病菌的菌丝平行生长 ,然后再侵入病菌内寄生。     

昆明裂腹鱼不同组织乳酸脱氢酶同工酶研究

采用不连续聚丙烯酰胺凝胶电泳法,对昆明裂腹鱼的眼球、心脏、肾脏、性腺、脾脏、肝胰脏、脑、鳃和肌肉等9种组织的乳酸脱氢酶同工酶(LDH)进行了测定。结果表明:昆明裂腹鱼LDH共有15条酶带表现出特异性,在不同组织中检出的LDH酶带数量不同,以肝胰脏中最多,共检出9条;在酶活性方面,LDH在脑、鳃、肌肉和肾脏等组织中活性最强,而在眼球组织中最弱。     

Detection and localization of viruses in orchids by tissue-print hybridization

A tissue-print hybridization assay for the detection and localization of viruses in orchids is described. Orchid leaves were cut transversely and the cut surfaces were printed on to nitrocellulose paper. Because orchid leaves are often succulent, there is excellent transfer of plant sap to the membrane, resulting in clear tissue prints. The nucleic acid on the nitrocellulose membrane was then hybridized to radio-labelled cDNAs of cymbidium mosaic virus (CyMV) and odontoglossum ringspot virus (ORSV), and the viruses were detected by autoradiography. The assay was able to detect as little as 20 pg of purified virus, which is 2–3 orders of magnitude more sensitive than the enzyme-linked immunosorbent assay (ELISA) for CyMV. When tissue prints derived from different parts of the plants were used for hybridization, the method was able to show the distribution of viruses within the plants. On the basis of its sensitivity and ease of use, this method should find wide application in the detection and localization of viruses in orchids as well as in other succulent plants.     

Effects of Diet Dilution during the Finishing Period on the Performance and Carcass Characteristics of Broiler Chickens

An experiment was conducted to study the response of broiler to diet dilution during the finishing period. Sixty 29-day-old commercial Avian male broiler chicks were assigned to two groups randomly, with 30 broilers each. Birds were offered a conventional finishing diet or with 10% dilution diet with ground rice hulls from 29 to 49 days of age. The result showed that there were no significant differences between the effects of diet dilution and the control on final body weight, growth rate and feed conversion efficiency. Diet dilution led to a reduction in abdominal fat weight, whereas carcass and breast muscle weight were not affected.     

转Bt基因抗虫棉卡那霉素田间鉴定技术研究

对转基因抗虫棉不同时期、不同叶片对卡那霉素不同浓度的反应及其与棉花抗虫性的关系进行了较系统的研究.结果表明,选取4 000 mg·L-1的卡那霉素液在棉花苗期、蕾期涂抹棉株倒二片平展叶最适宜,田间卡那霉素反应与田间棉铃虫发生实况结果吻合率高.说明棉花田间抗卡那霉素反应能够准确检测转基因抗虫棉,可以作为一种快速简便的田间检测转基因抗虫棉的方法.     

香蕉新品种“红研二号”的特异性研究

利用DUS检测方法和原理,对香蕉新品种“红研二号”与近似品种“巴西蕉”的48个性状进行差异性分析并进行特异性评价。结果表明：香蕉新品种“红研二号”质量性状的假茎、叶柄基部、叶柄及叶中脉背部的颜色为紫褐色（8010-R30B）,果轴（穗轴）基部的1/3处为紫褐色（8010-R30B）,为特异性的性状;这些紫褐色（8010-R30B）的特异性状,促成“红研二号”花青素含量较高,植株的抗氧化能力增强,表现出检测植株的抗衰老能力强;同时,其48个性状能稳定遗传,果实表皮与“巴西蕉”的颜色基本一致,但果实产量等性状总体优于“巴西蕉”,本研究对该品种的推广具有指导意义。