Breeding ecology of Styan's Bulbul Pycnonotus taivanus in Taiwan

The breeding ecology of Styan's Bulbul Pycnonotus taivanus , an endemic species in Taiwan, was studied in Kenting, Taiwan. The duration of the breeding season of Styan's Bulbul stretched from March to July in 1983. The average clutch size was 3.3 eggs ( n =34), and hatching success was 60%. The average number of nestlings at hatching was 2.7 per clutch, and 73% of the young fledged. Styan's Bulbuls selected their nest sites among dense vegetation. In the study area, 75% ( n =84) of nests were found in the Indiapoon Beautyleaf tree Calophyllum inophyllum , which had a relative vegetation density of only 33.5%. Factor analysis was used to analyse 13 nest-site characteristics of 63 nests, and five factors accounted for 69% of the variation.     

Callus Induction by (2-Chloroethyl) Phosphonic Acid on Cultured Cotton Ovules

The response of cultured cotton (Gossypium hirsutum L.) ovules to the ethylene releasing growth regulator, (2-chloroethyl) phosphonic acid (ethephon), was measured. Control ovules grown on a complete liquid medium without hormones continued the differentiation normal for cotton, although at a slower rate than in vivo. When ethephon was added to the medium, normal organ and fiber development was inhibited but callus was induced from the micropylar end of the ovule. The callus was extremely friable and produced many free cells in the culture medium. Dry weight of the callused ovules increased over 4-fold and total cell number increased 56% over the controls. Apparently ethylene released from the ethephon stimulated both cell division and cell expansion in forming the callus.     

DIFFERENTIAL THRESHOLD AND PSYCHOPHYSICAL POWER FUNCTION OF SWEETNESS SENSATION: APPLIED PSYCHOPHYSICS AND PROSPECT THEORY ON FORMULATING BAKING PRODUCTS

The main purpose of this project was to develop the optimal sweetness sensation framework for baking products. Phase 1 was designed to measure consumers' differential thresholds of sweetness sensation when the sweetener contents of various sweetener‐leveled products were increased and lowered by using the constant stimuli method. Results indicated that the consumers' differential thresholds increased when the initial sweetener levels of products increased. Phase 2 was designed to establish the psychophysical power function of sweetener‐content changes and consumers' psychological sensation of products with different sweetener levels by adopting the magnitude estimation method. Regardless of the initial sweetener levels of products, the results showed that consumers perceived the products as less sweet immediately after the sweetener contents of products dropped by even a small amount; however, consumers perceived products as sweeter only when products dramatically increased in contents of sweetener.     

The Species Problem in Plant Taxonomy in China

Nooteboom (1992) and Peter Raven (pers. comm. ) have pointed out that Chinese taxonomists often hold a narrow species concept and that this may due to the small volum of collections, especially type specimens, available to them which led to the unadequate study on the variability of the species. Raven remarked that “this leads me to believe that the actual concept of species used in plant systematics in China tends to be fairly typological”. What they said are by no means unreasonable. Indeed, the taxonomical status of a considerable number of species in the Chinese flora is probably open to question. New species based on a single character or solely on vegetative characters are of frequent occurrence. Evidences from a very limited number of researches on the patterns of plant variation heretofore available in China have shown that some “species” are, in fact, ecological races ( Clinopodium ), geographical races (Cunninghamia & Indigofera ), or taxa with topoclinal variation (Lespedeza & Rhododendron ). Species based on plasticity of phenotype variation have been or still regarded as “good species” ( Rorippa ). Segregates of an interspecific hybrid with diverse leaf characters have been given different species names ( Ilex ). The originally complicated situation in taxonomy of an agamic complex becomes even more complicated after the publication of additional new species (Malus). A careful analysis of a species with rather complicated patterns of variation leads to the combination of 25 specific names, of which 10 were published in the 80’s by Chinese taxonomists ( Clematoclethra ). Examples of these kinds will greatly increase with the broadening of research work at the species level. Orthodox plant taxonomy is based largely or solely on morphological characters. The exomorphic characters have the practical advantage that they are relatively easy to observe and to record. The taxonomical species concept can meet the needs of general purpose classification. But the notion that the taxonomical species concept is a solely intuitive judgement or preference of an individual worker and one could hardly say what is right and what is wrong is quite problematical. The species category today is much more capable of objective interpretation than ever before. A correct species concept stems from a correct and thorough understanding of the nature of variation pattern of plants and its taxonomical value. Hence, as a herbarium taxonomist, the first thing is to study as many collections as possible. Secondly, the incorporation of evidence from other sources whenever possible is highly desirable. These evidences,if they are not very useful as taxonomical criteria, are frequently of great significanee in contributing to a better understanding or interpretation of the variation pattern of a given taxon. The taxonomist might find the discontinuities he seeks better expressed in either the phenotypic or the genetic variation. A logical application of these two sorts of criteri-a would lead to a more rational classification at the specific level in a great many genera.     

中国台湾种子植物区系的性质、特点及其与大陆植物区系的关系

台湾位于欧亚大陆东南缘的海洋中,地处热带的北部和亚热带的南部,约为21°45′~15°56′N,119°18′~124°34′E,是中国最大的岛屿。它是受季风气候强烈影响的地区之一,热量丰富,雨量充沛,干湿季明显。具有一个非常丰富的岛屿和山区植物区系。就其种子植物而言,约有186科,1201属,3656 种,包括热带属742属,温带属346属。根据台湾植物区系中各大科、主要植物群落优势种和中国特有种的地理分布以及热带属在整个植物区系中的主导地位,台湾地区的植物区系主体具有明显的亚热带性质。中国台湾本地特有种十分丰富,其比例远高于中国特有种的比例。这似乎表明台湾植物区系是一个古老区系在多次地质事件侵袭后又起活化的历史演变的结果。新老成分并存、共同发展是台湾植物区系的重要特点。通过台湾全部属和非特有种在周边地区地理分布的分析,中国台湾植物区系与中国大陆的关系最为密切,是东亚植物区系的重要组成部分,因此在植物分区上应属于泛北极植物区的东亚植物区系。     

李温恙螨亚科Subfamily Leeuwenhoekinae的分类修订和一新属的记述(真螨目,恙螨科)(恙螨研究ⅩⅩⅩⅢ)

本文将恙螨科Trombiculidae里的李温恙螨亚科Subfamily Leeuwenhoekinae的分类系统加以修订。到目前为止,该亚科所包含的属,包括本文所叙述的一新属在内,共有八个属:Leeuwenhoekia,Odontacarus,Chatia,Hannemania,Whartonia,Shunsennia,Sasacarus和Multisetosa n.gen.,并编成八个属的检索表加以区分。多毛恙螨属Multisetosa是一个新属,它的主要特征是盾片上有4—6对侧缘刚毛;眼片远离盾片,在二者之间有盾眼毛2根;背刚毛数多而密,往往在100根以上,160根左右。     

昆虫线粒体发生的生化和亚显微结构的研究

线粒体在细胞中的发生目前有各种观点的争论,其理论意义涉及到真核细胞的起源和进化、染色体和线粒体两个遗传体系之间的相互关系以及生物膜合成和组装机理等。我们对处于分化中的昆虫胸肌线粒体的观察结果是:(1)对粘虫变态期的呼吸和细胞色素氧化酶活力测定表明蛹期第8天的组织形成阶段是胸肌细胞分化和其线粒体发生的开始。电镜观察表明,线粒体形成分两个阶段:由颗粒结构(可能是酶蛋白与脂的复合体)装配成膜片和膜泡;由膜泡分化出内嵴,进而发育为线粒体。(2)QO₂值,P/O比和ATP酶活力的出现与膜结构的分化发育相平行。α-甘油磷酸氧化酶系统比谷氨酸氧化酶系统装配早;电子传递酶系比磷酸化酶系装配早。(3)蝗虫胸肌分化过程的电镜观察证明;先形成内膜小泡(直径约0.1微米左右),后形成外膜,组成简单线粒体;后者进一步分化发育为成熟线粒体。(4)QO₂值,P/O比和ATP酶活力与膜结构分化发育相平行。ATP酶的出现与能量转涣功能呈平行关系。膜形成早期和“幼稚”线粒体阶段,ATP酶尚未装配。(5)综合上述结果:线粒体膜由非膜结构逐步组装形成,线粒体内膜的各酶系组装次序不同步,线粒体DNA控制合成的膜蛋白在膜结构形成中似乎起核心和骨架作用;线粒体总组装过程在不同细胞中表现为多种途径和方式。     

大豆食心虫Leguminivora glycinivorella(Mats.)Obraztsov的研究

大豆食心虫是我国东北地区大豆上的重要害虫。此虫一年发生一代,以老熟幼虫在土内越冬。成虫于七月下旬至九月上旬间出现,盛期在八月中旬左右。于成虫盛期后3—5天和10—12天为卵及幼虫孵化盛期。卵及幼虫孵化盛期历年比较一致,而成虫发生盛期个别年有所不同,其原因主要与气象条件有关,尤其是和降雨关系比较密切。成虫的寿命与产卵和温、湿度有密切关系,高温、低湿成虫寿命短,同时也影响到卵的发育和孵化。新孵化的幼虫在豆荚上停留时间很短,入荚时在荚面筑了一个丝网,为药剂防治造成一定的困难。幼虫在入荚过程中有一定程度的死亡,不同大豆品种中幼虫死亡率是不同的,最高达92.0%,最低仅为16.0%,可见在大豆中有较好抗虫性品种的存在,这是值得利用的一个因素。幼虫于豆荚内取食至老熟即脱荚,于土内3—15厘米处筑茧越冬,潜土深度以3—6厘米最多,作茧部位以壠台上为主。幼虫在土内生活期长达十个月以上,其越冬死亡率平均为14.26%,但在化蛹前死亡率高达45.33—82.27%,蛹前幼虫死亡率高主要是生活力减弱所致,而蛹对环境适应力更较幼虫为低,如埋于3厘米以下或土壤湿度低于5%时,则完全不能羽化。因此,利用农业防治具有很大意义。 关于防治此虫的办法:栽培抗虫品种,如铁荚四粒黄及吉林一号大豆品种,可较现有一般推广品种(小金黄一号)降低虫食率50—70%,其次是推行耕、耙豆后麦茬,提倡较远距离轮作以及使玉米混作大豆及大豆小麦间作等均能减轻为害。在为害严重地区须进行药剂防治:在成虫发生盛期撒布6%666和6%666+5%DDT(4:1)混合粉剂。于幼虫孵化盛期前撒布6%666+5%DDT(4:1)混合粉剂均有良好效果(70%以上),但后者在多雨年份效果不稳定,宜采用2%百治屠粉剂,雨季使用效果亦能稳定在70—80%。