槲寄生的一个新寄主植物

通过野外采集标本、查阅文献资料及标本鉴定,发现槲寄生的一个新寄主植物——北京丁香(Syringa reticulata subsp. pekinensis),扩大了槲寄生的寄主范围,为槲寄生人工栽培和对寄主植物的选择提供参考资料。     

槲寄生挥发性成分研究

目的：研究槲寄生挥发性成分。方法：利用水蒸汽蒸馏法提取槲寄生挥发性成分,用GC/MS进行分离测定,结合计算机检索技术对分离的化合物进行结构鉴定,应用色谱峰面积归一化法计算各成分的相对百分含量。结果：分离出119个成分,确定了66个化合物,占挥发油总量的77．31％。结论：槲寄生挥发性成分大于2％的化学成分有12种。     

槲寄生的生物学特性、利用与保护

槲寄生是一种有药用价值的半寄生植物,其繁殖方式主要借助鸟类对种子的传播。随着人们对它认识的深入。开发利用的力度也越来越大,加上为槲寄生传播种子的鸟类越来越稀少．对槲寄生的生存和繁衍形成了威胁。旨在介绍槲寄生的生物学特性、利用与保护现状,希望引起广大读者的关注。     

云杉矮槲寄生内寄生系统的解剖学研究

采用石蜡切片和显微观察的方法,以被云杉矮槲寄生侵染的青海云杉枝条为材料,从解剖学水平观察云杉矮槲寄生的内寄生系统。结果表明:云杉矮槲寄生的内寄生系统由分布在寄主皮层内的皮层根和镶嵌在寄主木质部中的吸根组成。皮层根可以沿着寄主枝条,通过挤压寄主皮层细胞的方式扩展,并穿透寄主表皮层形成云杉矮槲寄生的寄生芽;在靠近或接触寄主次生韧皮部时形成吸根,吸根顶端细胞定向穿透寄主韧皮部和形成层,侵染木质部,并沿木射线方向生长。当云杉矮槲寄生侵入寄主以及皮层根向外生长时,寄主表皮层发生加厚现象。随着云杉矮槲寄生侵染部位的寄主皮层细胞数增多,引起枝条膨大。研究认为,云杉矮槲寄生可以进行系统侵染,反映了云杉矮槲寄生与其寄主在组织水平上的相互作用。     

槲寄生的研究与开发利用

本文对槲寄生的生物学特性、化学成分、药理作用及开发利用等作了阐述。     

槲寄生蛋白抗癌活性研究及新成分鉴定

目的评价槲寄生蛋白的抗癌活性,鉴定其中的新成分。方法以H22肝癌移植瘤为模型,评价槲寄生蛋白对肿瘤生长的抑制作用。采用CMSepharoseF．F．弱阳离子交换色谱,分离出一种低含量的槲寄生蛋白。基质辅助激光解吸飞行时间质谱测定其分子量。蛋白电泳后转印PVDF膜,采用Edman降解,测定该成分A,B两链的N端序列。结果槲寄生蛋白对H22的抑制率达80．2％,其中的CMO为未见报道的新成分。结论槲寄生总蛋白主要含有3种成分,且具有显著的抗癌活性。     

槲寄生的生物学特征及鸟类对其种子的传播

2001年9月至2002年1月在黑龙江省尚志市帽儿山林场研究了槲寄生(Viscum coloratum)的生物学特征及鸟类对其种子的传播。槲寄生寄主共有9种阔叶树,杨树占比例最大,达73．3％。78．0％的槲寄生个体以杨树为寄主。多数槲寄生着生在杨树主干侧枝(43％)和细侧枝(42％)上,主干上仅l5％。寄主和槲寄生本身都呈聚集分布。槲寄生有两种色型果实,在量度上无明显差异。果实由果皮、果肉和种子构成,种子外面包裹一层胶质层。在帽儿山秋、冬季常见的7种食果实鸟类中,只有太平鸟（Bombycilla garrulus)在野外觅食槲寄生果实,斑鸫（Turdus naumanii)在笼养无其它食物时才食,其余5种鸟类拒食。太平鸟在11月以后觅食槲寄生果实频率增大。除根寄生果实外,太平鸟共可食帽儿山常见l7种肉质果中的12种。太平鸟在吞食果实后,种子外包胶质层随粪便排出,形成“种子线”粘在树枝上,槲寄生种子被传播到适宜的生境,在春天萌根生长。笼养太平鸟时,种子在消化道的滞留时间约11min,这意味着在野外很长的扩散距离。槲寄生和太平鸟之间形成了特定的互利互生系统。     

槲寄生中多肽B6的分离纯化和一级结构测定

采用离子交换、凝胶过滤、HPLC等提取、分离、纯化方法,从我国东北产槲寄生中得到第二种新成分槲寄生毒素B6。Edman降解结合质谱技术测定其一级结构为KSCCPNTTGRNIYNTCRFAGASRERCAKLSGCKIISASTCPSDYPK。进化分析说明该成分与白果槲寄生中的槲寄生毒素同源性很高,亲缘关系较近。同源模建表明B6是一种高α-螺旋的多肽。     

中国槲寄生属花粉形态的研究

首次系统地报道中国槲寄生属10种植物花粉形态。通过光学显微镜和扫描电镜观察,国产槲寄生属种类可按花粉的外壁纹饰分为两大类群,与形态上划分相一致。类群Ⅰ(8种)具不显著或近光滑的外壁纹饰,这一类型又可分为2个亚型:纹饰在花粉各个部位基本上是一致的和纹饰在赤道和极、沟两侧不一致的;类群Ⅱ(2种)外壁具显著的杆状纹饰。但花粉性状对形态上相近的种类鉴定意义不大。还讨论了槲寄生属花粉的可能的演化趋势。     

扁枝槲寄生的生药学鉴定研究

我国各地所使用的常用中药“桑寄生”,除《中国药典》收载品种外 ,还来源于同科多种植物 ,扁枝槲寄生即为商品药材之一 ,并已载入《四川省中药材标准》。为便于药材鉴定和进行质量评价 ,本文对扁枝槲寄生进行了显微组织特征的分析 ,并用 TL C法和 UV法对其进行了分析     

中国叉柱兰属(兰科)一新记录种——匍匐叉柱兰

报道中国兰科叉柱兰属一新记录种——匍匐叉柱兰(Cheirostylis serpens Aver.)。该种以附生小草本,茎匍匐状,叶无柄,唇瓣白色,及向内卷缩的肉质边缘增生将唇瓣分为明显的上下两个唇而与其他种类相区别。     

Campylocentrum benellii and C. paludosum spp. nov. (Angraecinae–Orchidaceae): two new leafless species from Brazil

The leafless condition is present in two neotropical epiphyte genera of Orchidaceae, Campylocentrum and Dendrophylax. Only the first one is reported from Brazil, where seven leafless species are recorded, and four of them are endemic. This study describes two new species of Campylocentrum from the Atlantic forest of São Paulo state and Amazon forest of Acre, Mato Grosso and Rondônia states. It also provides a key to the Brazilian species of leafless Campylocentrum, illustrations, and a discussion of the affinities of the new species with allied ones.     

中国槲寄生属植物及其寄主的地理分布

对槲寄生属植物在世界的分布状况和在中国的分布特点进行了讨论。通过对其寄主植物进行统计并分析其分布区类型的特点,结合该属目前的核型分析结果和现存类群的分布特点,论证了槲寄生属植物属古南大陆起源,并对其起源时间和迁移路线作了推测。     

Diversity of flowering and fruiting phenology of trees in a tropical deciduous forest in India

BACKGROUND AND AIMS: In the dry tropics, vegetative phenology varies widely with tree characteristics and soil conditions. The present work aims to document the phenological diversity of flowering and fruiting with reference to leafing events in Indian dry-tropical tree species. METHODS: Nine tree species, including one leaf-exchanging and eight deciduous showing varying leafless periods, were studied. Monthly counts of leaves, flowers and fruits were made on 160 tagged twigs on ten individuals of each species for initiation, completion and duration of different phenological events through two annual cycles. KEY RESULTS: Variation in flowering relative to leaf flushing (which occurred just prior to or during a hot, dry summer) revealed five flowering types: summer flowering (on foliated shoots), rainy-season flowering (on foliated shoots following significant rains), autumn flowering (on shoots with mature leaves), winter flowering (on shoots undergoing leaf fall) and dry-season flowering (on leafless shoots). Duration of the fruiting phenophase was shortest (3-4 months) in dry-season and winter-flowering species, 6-9 months in rainy-and autumn-flowering species, and maximum (11 months) in summer-flowering species. A wide range of time lag (<1 to >8 months) between the start of vegetative (first-leaf flush) and reproductive (first-visible flower) phases was recorded in deciduous species; this time lag was correlated with the extent of the leafless period. A synthesis of available phenological information on 119 Indian tropical trees showed that summer-flowering species were most abundant (56 % of total species) amongst the five types recognized. CONCLUSIONS: The wide diversity of seasonal flowering and fruiting with linkages to leaf flush time and leafless period reflect the fact that variable reproductive and survival strategies evolved in tree species under a monsoonic bioclimate. Flowering periodicity has evolved as an adaptation to an annual leafless period and the time required for the fruit to develop. The direct relationship between leafless period (inverse of growing period) and time lag between onset of vegetative and reproductive phases reflects the partitioning of resource use for supporting these phases. Predominance of summer flowering coupled with summer leaf flushing seems to be a unique adaptation in trees to survive under a strongly seasonal tropical climate.     

桑蚕畜禽生态系统的物质和能量流动

栽桑养蚕是我国农村的一项传统副业,至少已有5000年的悠久历史。传统的栽桑养蚕体制对自然资源和设备的利用不尽合理。例如,在江浙蚕区,每年桑树无叶期长达5个月之久,其间每1ha桑园大约接受1.26×10~(13)J的太     

短梗千金藤，越南防己科新记录种

报道了越南防己科(Menispermaceae)一新记录种:短梗千金藤(Stephania brevipes Craib)。据文献记载,该种仅分布于泰国,现首次在越南发现其分布。本种与粪箕笃(S. longa Lour.)形态相近,但叶宽三角状卵形至三角状扁圆形,雄花序小,腋生或生于无叶的茎上,总梗较短,花萼淡黄色,花瓣红紫色,内果皮外部沟数目较少而与后者不同。还提供了该种详细的形态学描述、图版、分布及生态学等信息。凭证标本保存在越南国立自然博物馆标本馆(VNMN)和中国科学院华南植物园标本馆(IBSC)。     

中国云南毛茛科毛茛属一新种——哀牢山毛茛

描述了中国云南毛莨科Ranunculaceae一新种--哀牢山毛莨Ranunculus ailaoshanicus W.T.wang。此种在体态上与圆裂毛莨R．dongrergensis Hand．-Mazz．极为相似,但以茎较低矮,无叶,花较小,花瓣较小,长圆状椭圆形,脉不明显而相区别。     

Hoya aphylla (Apocynaceae,Asclepiadoideae), a new leafless species from Laos

The leafless species Hoya aphylla Aver. N.S. Khang & Averyanova (Apocynaceae) is described and illustrated as a new species for science from Hin Nam No National Protected Area of Laos (central Laos, Khammoune province). In its floral morphology, this new species may be similar to H. lyi, H. carnosa and H. multiflora, but it differs in corona color and shape of corona segments. Like the first two mentioned species, the new species may be referred to the type section of the genus, but in terms of it its leafless habit it exhibits an isolated position.     

Endogenous free polyamines and their role in fruit set of low and high parthenocarpic ability citrus cultivars

Endogenous free polyamines (PAs), putrescine, spermidine and spermine, from developing fruitlets of Citrus species (Citrus unshiu Marc. and Citrus clementina Hort ex Tanaka) which differ in their parthenocarpic ability, and from uniflowered leafy and leafless inflorescences differing in their ability to set, have been determined by dansylation and separation of dansyl derivatives by HPLC. No significant differences in PAs content were observed between species or between leafy and leafless inflorescences which, nevertheless, significantly differed in fruit set. However, significant differences in their content were found in developing fruitlets, depending on the preceding flowering intensity of the tree and on the fruitlet load. These results suggest that, in Citrus, PAs may act as a nitrogen source rather than a regulator of fruit set.