首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
采用“外类群对比准则”的性状分析方法,对我国特有植物四棱草属Sohnabelia及其近缘属筋骨草属Ajuga,香科科属Teucrium(唇形科Labiatae)和莸属Caryopteris,大青属Clerodendrun(马鞭草科Verbenaceae)等5属6种主要植物叶进行比较研究,结果表明;叶形卵圆形或椭圆形;叶缘均具齿,叶脉同为羽状脉;三级脉为分枝型和贯串型;边缘末级脉均为不完全型:齿型为  相似文献   

2.
采用“外类群对比准则”(OutgroupComparisonCriteria,Carcarft1983)的性状分析方法,对我国特有植物四棱草属Sohnabelia及其近缘属筋骨草属Ajuga,香科科属Teucrium(唇形科)和莸属Caryopteria大青属Clerdendron(马鞭草科)等5属6种主要植物比较研究,首次发现在这些植物叶片上,具有一种新的毛状体,其形状呈箭形,故定名为箭形毛(Arrow—shaped—hair),在扫描电子显微镜下观察是由头部、柄部和基部组成,在光学显微镜下,确认这类毛状体属于多细胞单列毛,由细胞变形而成形。此外,尚有长柔毛(Shag-hair),盾状毛(Peltate—hair)和鳞片毛(Scales—hair)等四种类型。从以上毛状体的微形态特征及其演化规律,作者认为四棱草属和近缘属在唇形科与马鞭草科系统演化框架里,可能是处于中间过渡类型。  相似文献   

3.
中国美绥螨属—新纪录ANEWRECOEDOFAMEROSEIUSFROMCHINA¥WANGZi-cun;BAIXue-li(InstituteofEndemicDiseaseControl,NingxiaHuiAutonomousRegion,Yi...  相似文献   

4.
中国寄螨属一新纪录(蜱螨亚纲:寄螨科)ANEWRECORDOFTHEGENUSPARASITUSFROMCHINA(ACARI:PARASITIDAE)¥WangZicun;MaLiming(InstituteofEndernicDiseaseCon...  相似文献   

5.
国产多榔菊属两新种陈艺林(中国科学院植物研究所北京100093)TWONEWSPECIESOFDORONICUMLINN.(COMPOSITAE)FROMCHINACHENYiLing(InstituteofBotany,theChineseAc...  相似文献   

6.
采用“外类群对准则”(OutgroupComparisonCriteriaCarcarft1983)的性状分析方法,对我国特有植物四棱草属Sohnabelia及其近缘属缘筋骨草属Ajuga,香料科属Teucrium(唇形科)和莸属Caryopteria大青属Clerdendron(马鞭草科)等5属6种主要植物比较研究,首次发现在这些植物叶片上,具有一种的毛状体,其形状呈箭形,故定名为箭形毛(Arr  相似文献   

7.
中国果瓣螺属─新纪录(肺螺亚纲:基眼目:耳螺科)ANEWRECORDOFCARYCHIUMFROMCHINA(PULMONATA:BASOMMATOPHORA:ELLOBIIDAE)¥CHENDe-niu(InstituteofZoology,Aca...  相似文献   

8.
中国黄耆属一新种   总被引:1,自引:1,他引:0       下载免费PDF全文
朱相云  陈家瑞   《广西植物》1995,15(2):112-113
中国黄耆属一新种朱相云,陈家瑞(中国科学院植物研究所,北京1000-93)ANEWSPECIESOFASTRAGALUS(LEGUMINOSAE)FROMCHINA¥ZhuXiangyunandChenChiarui(InstituteofBotan...  相似文献   

9.
通过对我国特有植物四棱草属Schnabelia及其缘属茎和叶柄的解剖研究,发现四棱草属的二种植物四棱草S.oligophylla.四齿棱草S.tetoclonta和莸属的单花C.nepetaefolia的节的类型均为单叶隙、单叶、迹,且叶迹在皮层中从左右两则各产生一细小的分支;而筋骨草属的紫背金盘A.nipponesis和香料科属(Teucrium)的血见愁(T.viscidum)的节的类型为单叶  相似文献   

10.
四棱草属及其近缘属筋骨草属Ajuga,香科科属Teucrium(唇形科Labiatae),莸属Caryopteris,大青属Clerodendrum(马鞭草科Verbernaceae)5属,6种代表植物的叶表皮细胞形状、气孔类型和毛状体类型的比较研究结果是:(1)叶上表皮细胞形养 深小纹状不规则形,浅波纹状不规则形和浅波纹状四边形;(2)气孔类型是不规则型,平列型,横列型和等位模列型。(3)毛状体  相似文献   

11.
12.
反刍动物取食量及其调节   总被引:5,自引:1,他引:4  
陈化鹏  马建章 《兽类学报》1997,17(4):292-300
反刍动物取食量受动物因素、环境因素和植物因素的影响。取食量的估计可基于5个途径:饲料生物量或动物体重的短期变化;食道或瘤胃瘘管技术;食口计数法;日粪便排出量和消化率的测定;双链烷技术。取食量的调控机制极为复杂,任何单因子都很难给予完全的解释。多因子途径将有助于这一问题的解决。中枢神经系统应当作为探索这一课题的重要基础。无论是从生理学、解剖学或行为学的途径,重要的是寻找和发现中枢神经系统和来自动物体内环境各种信号间的联系,并且探索建立这种联系的巧妙机制以及这种机制是如何在短期和长期的条件下对取食量加以调控。  相似文献   

13.
Wood of two specimens of Ephedra from high alpine localities is nearly vesselless: E. gerardiana from 4,750 m in Tibet, and E. rupestris from 4,300 m in Argentina. Ephedra gerardiana from lower elevations in the Himalayas has more vessels, although even there they are not abundant. Instances in other species of Ephedra in which extensive areas of latewood or even entire growth rings are vesselless are cited; these tend to occur in high deserts with climates somewhat less extreme than those of the alpine localities. Near-vessellessness is interpreted as an adaptive condition in which the proportion of tracheids, conductively safer than vessel elements, reaches a maximum. Near-vessellessness in Ephedra wood is probably reversible within limits, and should be likened to production of latewood to the exclusion of earlywood. Comparisons are offered to dicotyledons in which abundance of vessels is lowered with respect to ecological extremes.  相似文献   

14.
15.
中国的原手斧及其传统   总被引:3,自引:3,他引:0  
安志敏 《人类学学报》1990,9(4):303-311
中国的原手斧包括双面器、单面器和三稜器三类,分布于华北、华中和华南的几十处地点,以华中的发现最为丰富。它们属于旧石器初期的遗存,旧石器中期以后已大体绝迹。 中国的原手斧与砍砸器、石球等共存,不同于阿舍利文化传统的手斧。中国旧石器初期至少有两个文化传统,即以原手斧为代表的砾石工业和以周口店文化为代表的石片工业,但华北的原手斧传统后来已被石片工业所完全代替。  相似文献   

16.
催产素及其受体与哺乳动物的生殖   总被引:5,自引:0,他引:5  
范衡宇  杨增明 《动物学报》2001,47(4):453-458
催产素(OT)是一种9肽激素,主要由哺乳动物下丘脑产生,以神经内分泌,旁分泌或自分泌形成,在哺乳动物生殖过程中发挥重要作用,催产素受体(OTR)是与G-蛋白相耦联的膜蛋白,通过激活磷脂酶C发挥其生理作用,OT在交配,分娩,哺池时由神经垂体(垂体后叶)脉冲式释放,促进子宫平滑肌和乳腺肌上皮细胞收缩,利用精子运行,胎儿娩出和射出乳汁,OT在中枢神经系统中参与调节母性行为,在性腺中促进某些物种的黄体形成,OT与PGF2a共同作用使有蹄动物黄体退化,以上过程都依赖于OT和OTR基因的时空特异性表达,多种激素参与它们的表达调控,但OT的生理作用有时也可被其它途径所替代。  相似文献   

17.
18.
19.
20.
An examination of the endothecial thickenings in 44 species of Iridaceae, selected from the four subfamilies and all major tribes, provides useful information about generic and tribal relationships in the family. U-shaped thickenings occur in Nivenioideae and Iridoideae—Sisyrinchieae, the latter the least specialized tribe of its subfamily. The occurrence of helical thickenings in all members examined of Iridiodeae tribes Irideae, Mariceae, and Tigridieae (a putatively monophyletic group) and Ixioideae is consistent with the recognition of these two lines as distinct taxa based on anatomical, morphological, phytochemical, and in the case of Ixioideae, palynological criteria. Baseplate thickenings are restricted to Patersonia. However, the shrubby Cape genera—Nivenia, Klattia, and Witsenia—have U-shaped thickenings which show a tendency for the bars on the inner periclinal cell walls to anastomose, suggesting a trend towards the baseplate condition in Patersonia. This accords with a suggested relationship between these genera, based on anatomical and flavonoid similarities. The pattern of variation in endothecial thickenings in Iridaceae is consistent with the phylogeny proposed by Goldblatt (1990). The distribution of thickening types within the family does not make it possible to polarize this character, but the most parsimonious interpretation assumes that U-shapes are basic. However, in at least some other monocotyledonous families the pattern suggests that U-shaped thickenings are derived from helices.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号