草地早熟禾无融合生殖的细胞学鉴定

应用胚囊整体染色透明法，对不同品种和来源的草地早熟禾无融合生殖进行了初步研究。从观察胚囊的发育过程入手，探讨了草地早熟禾（ＰｏａｐｒａｔｅｎｓｉｓＬ．）的３个引进栽培品种：Ｗａｂａｓｈ、Ｆｙｌｋｉｎｇ、Ｋｅｎｔｕｃｋｙ以及采自甘肃天祝、肃南和甘南的３个野生种群的无融合生殖的类型和特点。指出草地早熟禾是兼性二倍体无孢子生殖，无融合生殖率因品种和来源不同而异，Ｗａｂａｓｈ为６５％，Ｋｅｎｔｕｃｋｙ为５４％，Ｆｙｌｋｉｎｇ为４８％，天祝、甘南、肃南的３个草地早熟禾野生种群的分别为２３％、１２％和５％。此外，还观测到了草地早熟禾的多胚现象。     

Ovules that failed to form seeds in zinnia (Zinnia violacea Cav.)

The structure of ovules that failed to form seeds after compatible pollination in double-flowered zinnias (Zinnia violacea Cav.) was investigated by observing histological sections, and comparing the normal and abnormal development of the seeds. In an embryo sac of zinnia at anthesis, a large nucleus of fused polar nuclei was clearly recognized. Success in double fertilization was determined by the disappearance of this nucleus. In normally developing seeds, the cellular endosperm became vague at 5–6 days after pollination (DAP) and the developing embryos occupied the entire portion of the seeds up to 10 DAP. A number of ovules failed in fertilization for the lack of an embryo sac. In most of the aborted seeds, the embryo sacs degenerated, whereas the aborted embryos were still alive in a small number of aborted seeds. A small percentage of the aborted seeds exhibited an aborted embryo and an unfertilized fused nucleus of two polar nuclei or ‘single fertilization’. The three major problems suggested for the failure in seed formation in pollinated florets of zinnia included failure in fertilization, ovules lacking embryo sacs, and abortion of developing seeds.     

珠江三角洲园林植物信息管理系统设计

在收集、汇总和整理珠江三角洲园林绿化植物基本资料的基础上 ,运用Foxpro关系型数据库应用软件的管理功能 ,进行园林植物信息管理系统结构设计 ,以实现珠江三角洲园林植物信息 (文字、彩色图象 )的现代化管理     

IMAGING DIAGNOSIS—USE OF RADIOGRAPHY AND COMPUTED TOMOGRAPHY IN THE DIAGNOSIS OF A MINERALIZED YOLK SAC IN A BROWN KIWI (APTERYX MANTELLI)

A 12‐day‐old Brown Kiwi (Apteryx mantelli) was presented with anorexia, torticollis, head‐tilt, and coelomic distension. Radiographs showed an ill‐defined, fat‐opaque, coelomic mass displacing viscera craniodorsally. Curvilinear mineral opacities were superimposed over the ventral aspect of the mass. Computed tomography demonstrated the presence of mineral within the periphery of a fat attenuating mass consistent with a retained yolk sac. A deutectomy (yolk sac excision) was performed. Histopathology of the excised tissue confirmed the diagnosis of a retained yolk sac with multifocal mineralization.     

Yolk‐sac larval development of the substrate‐brooding cichlid Archocentrus nigrofasciatus in relation to temperature

In order to conserve and culture the cichlid fish Archocentrus nigrofasciatus, more information about its reproductive biology and its larval behavior and morphogenesis is necessary. Currently, temperatures ranging from 21 to 27 °C are used in ornamental aquaculture hatcheries. Lower temperatures are preferred to reduce the costs of water heating, and 23 °C is usually the selected temperature. However, there is limited information on culturing protocols for ornamental species and most of the information generated on this topic remains scarce. Thus, the present study examines the morphological development of Archocentrus nigrofasciatus during the yolk‐sac period up to the age of 100 h post‐hatching in relation to 2 temperature regimes used in ornamental aquaculture: a temperature of 27 °C (thermal optimum) and a decreased temperature of 23 °C (thermal tolerance). The results of this study suggest that the 27 °C temperature generates intense morphological changes in yolk‐sac development in a shorter period. This has advantages as it reduces the time of yolk‐sac larval development, and, thus, minimizes the transition phase to exogenous feeding and maximizes the efficiency at which yolk is converted into body tissues. The present paper provides necessary information to produce freshwater ornamental fish with better practices so as to increase larval survival and capitalize on time for growth.     

紫李子花芽外部形态和花芽、胚珠胚囊发育时期相关性的观察

紫李子的花粉发育及胚珠，胚囊的形成，是在春季萌芽过程中完成的．在花粉的发育过程中，花粉母细胞形成阶段较长，减数分裂期较短．在减数分裂期，第１次减数分裂后，在两个子核之间不产生细胞壁，不形成子细胞。第２次减数分裂后，４个子核之间产生细胞壁，形成四分体。花粉发育的同时，胚珠胚囊形成，各个发育时期与花芽的外部形态存在着密切的相关注。     

早期饲喂与禁食对新生肉雏消化系统和免疫器官发育规律的研究

选择160只刚出壳且卵黄吸收良好的AA肉仔鸡,随机分成2组,每组4个重复,每个重复20只鸡,一组为早期饲喂组,另一组为早期禁食组。分别在雏鸡出壳和1、2、3、5、7日龄时,从各重复组任取2只鸡,称重后解剖。取胰腺测定胰腺淀粉酶、蛋白酶和脂肪酶活性;取空肠测定蛋白酶和淀粉酶活性;取脾脏和法氏囊,称重,计算各免疫器官指数;摘取卵黄囊,称重,测卵黄囊液中鸡新城疫抗体水平。结果表明:(1)体重。早期饲喂组鸡的体重显著大于早期禁食组的鸡(p<0.05)。早期禁食组的鸡在禁食期间体重逐日下降,至48h龄时体重下降了4.1g,开始饲喂后体重才回升。而早期饲喂组鸡的体重则逐日增加。(2)免疫器官。早期饲喂组鸡的法氏囊指数和脾脏指数与早期禁食组的鸡比较差异显著(p<0.05),早期饲喂能促进免疫器官内部淋巴细胞的分化与增殖,并能提高卵黄囊中鸡新城疫抗体水平,组间差异显著(p<0.05)。(3)酶活性。早期饲喂组鸡的胰腺淀粉酶、脂肪酶、蛋白酶的活性和空肠淀粉酶的活性都高于早期禁食组的鸡(p<0.05),空肠蛋白酶的活性组间差异不显著(p>0.05)。早期禁食组的鸡在禁食期间,未测到空肠淀粉酶和蛋白酶的活性。(4)卵黄囊。早期饲喂组的鸡与早期禁食组的鸡比较,卵黄囊重差异不显著(p>0.05),但有降低趋势。     

Biological utilisation of pearl millet fluor fermented with yeasts and lactobacilli

Mixed culture fermentation of pearl millet flour withSaccharomyces diastaticus, Saccharomyces cerevisiae, Lactobacillus brevis andLactobacillus fermentum brought about an improvement in its biological utilisation in rats. Protein efficiency ratio, feed efficiency ratio, apparent protein digestibility, true protein digestibility, net protein utilisation, net protein retention, protein retention efficiency and utilisable protein values in case of pure culture fermented pearl millet four were higher than the control. Feeding of the fermented products did not bring about physiological, histopathological and haematological changes in rats.Chapaties and cutlets prepared from the fermented products were organoleptically acceptable.     

珠三角耕地利用转型的时空演化特征及其影响因素分析

为推进珠三角耕地保护、优化耕地利用格局,将耕地利用转型内涵进一步深化,从结构、效率和功能3个维度构建指标体系,运用熵权法、ArcGIS空间分析和灰色关联分析等方法揭示了珠三角地区耕地利用转型的时空演化特征及其影响因素。结果表明:(1)区域耕地利用形态诊断可以从结构、效率和功能三方面度量;(2)珠三角整体耕地利用综合转型水平呈上升态势,城市间综合转型水平差异明显并呈缩小趋势;(3)珠三角耕地利用综合转型在空间上呈“核心—边缘”分布特征,中心城市转型水平较低;(4)各市在结构、效率和功能转型3个层面的得分具有不均衡性,转型优劣有所差异,其中深圳效率转型指数上升293.12%,广州结构转型指数下降19.76%,中山功能转型指数下降20.69%。(5)城镇化率、人均GDP和人均固定资产投资对耕地利用转型的影响较为显著。综上,珠三角耕地利用朝优化方向转型,但区域间转型差异仍不可忽视。人口和社会因素对珠三角耕地利用转型具有较大的推动作用。     

基于PSR模型的珠江三角洲生态环境脆弱性评价

[目的] 揭示珠江三角洲生态环境脆弱性的时空演变特点及其原因,为区域发展提供理论依据。[方法] 利用生态压力度—生态敏感度—生态恢复力(pressure-sensitivity-restoration,PSR)模型、量化分级法和层次分析法(AHP),构建生态环境脆弱性综合指数,分析珠江三角洲不同时期的生态环境脆弱性特征。在此基础上,借助地理探测器的因子探测工具分析变量因素对生态环境脆弱性时空分布差异的影响程度。[结果] ①2000—2020年珠江三角洲生态环境脆弱性指数的变化范围为1.206 5～4.594 8,呈现微度脆弱等级; ②空间分布上,珠江三角洲中部地区的脆弱等级较高,东西部脆弱等级较低。此外,随着高程的增加,生态环境脆弱性程度减轻,中度和重度脆弱区面积比例减小; ③林地表现为潜在和微度脆弱等级,草地表现为中度脆弱,耕地、水域和未利用地以轻度脆弱等级为主,建设用地主要分布于重度和中度脆弱区; ④珠江三角洲生态环境脆弱性空间分异的主要影响因子为人口密度、植被覆盖指数及生物丰富度指数。[结论] 受人口增长压力的影响,研究时段内珠江三角洲生态环境脆弱等级提升。