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1.
星叶草叶脉序的形态学及其系统学意义   总被引:5,自引:1,他引:4  
在星叶草叶二叉分枝脉序中,网结脉中2条完全汇合叶脉与靠近脉中完全分离叶脉间未发现任 何形式的维管束汇合的中间类型,相反观察到了网结脉中不同程度的连接脉退化的痕迹,因此网结脉不可能由靠近脉形成;盲脉的出现与齿的退化、网结脉中连接脉的间断及非网结脉由分枝处间断等相关;上述事实表明星叶草叶的二叉分枝脉序应为一减化性状。  相似文献   

2.
独叶草叶宏观形态性状的变异式样的初步研究   总被引:2,自引:0,他引:2  
根据独叶草分布区内 8个居群的叶的 8个宏观性状在散点图上的表现 ,探讨了独叶草的形态变异式样。结果表明 ,独叶草在叶宏观性状上表现出了一定的变异性 ,这种变异性表现在不同居群间及由不同居群组成的区域上 ,但在居群间或由不同居群组成的区域间在性状上有不同程度的重叠。  相似文献   

3.
脉红螺消化系统的形态学研究   总被引:16,自引:2,他引:16  
侯林  程济民 《动物学报》1991,37(1):7-15
脉红螺消化系统由十二个器官组成。其消化管壁都由粘膜层、粘膜下层、肌层和外膜四层结构构成。作者对消化腺的细胞进行了较详细的描述,并利用组化方法测定消化腺细胞中含有的酶类。作者还对部分器官的超微结构进行了观察。  相似文献   

4.
根据保存良好的化石材料,对Gigantonoclea acuminatiloba的叶结构、小羽片形态和脉序作了详细记述和讨论。该种的蕨叶为奇数羽状复叶,通常由5枚大型的小羽片构成,小羽片基部呈匙形,并非以往推测的楔形;叶缘在下部具粗锯齿,在中、上部具重锯齿;顶端急尖形,两侧的锯齿有时并不对称。对叶脉特征也作了详细记述,否定了关于此种网眼内有盲脉(游离脉)的记录。同时对有些具很特征的褶皱、被误定为C  相似文献   

5.
独叶草形态学的研究III.花、果实和种子的形态和解剖   总被引:4,自引:0,他引:4  
本文报道独叶草 Kingdoinia uniflora 的花、果实和种子的形态结构规律。 花的各部分 多而无定数,呈螺旋状排列。花被片的脉序呈开放的二叉分枝,可分三类。雄蕊分能育和不 育两类,维管束单一,后者顶端的凹沟内具蜜腺,前者的花粉囊呈侧向-外向着生。心皮分化 为三部分,子房具柄,含1枚横生胚珠。开花时,心皮不完全闭合,属半开放型,近似黄连属(Coptis)植物。聚合瘦果,种子1枚,胚处于原胚期,胚乳丰富。文中还讨论了有关形态演化问题。  相似文献   

6.
水蛇亚科属于游蛇科,包含10个属。其中7个属为单型属。选取水蛇亚科14个形态学特征进行支序分析,并利用计算机软件Hennig86对水蛇亚科中8个属之间的系统发育关系进行初步探讨,结果显示水蛇亚科分为两支Gerarda和Fordonia两个属构成姊妹群,Cerberus、Erpeton和Homalopsis三个属也构成单系群,与Vorisetal(2002)的分子系统树相同,但Cantoria属的地位则与Vorisetal(2002)的明显不同。  相似文献   

7.
长果安息香属和秤锤树属植物叶片脉序研究   总被引:4,自引:0,他引:4  
杨庆锋  蔡雪珍  陈涛   《广西植物》1997,17(2):145-148
本文观察和描述了单种属长果安息香属和秤锤树属5种植物的叶脉特征。结果表明,两属植物的脉序特征比较一致;但各种之间也存在一些差别,根据这些差别可编出分种检索表;长果安息香与秤锤树属各种的三级脉特征明显不同,支持成立长果安息香属  相似文献   

8.
水蛇亚科属于游蛇科,包含10个属。其中7个属为单型属。选取水蛇亚科14个形态学特征进行支序分析,并利用计算机软件Hennig 86对水蛇亚科中8个属之间的系统发育关系进行初步探讨,结果显示水蛇亚科分为两支:GerardaFordonia两个属构成姊妹群,CerberusErpetonHomalopsis三个属也构成单系群,与Voris et al(2002)的分子系统树相同,但Cantoria属的地位则与Voris et al(2002)的明显不同。  相似文献   

9.
十字花科四属植物叶片脉序的比较研究   总被引:7,自引:0,他引:7  
对十字花科有争议的岩荠属Cochlearia,泡果荠属Hilliella,阴山荠属Yinshania,棒毛荠属Cochleariella植物的叶片脉序进行了研究。结果表明:岩荠属为环结曲行羽状脉,泡果荠属为直行羽状脉,阴山荠属为半直行羽状脉,棒毛荠属种的叶脉与浙江泡果荠相似。前3属植物在网眼的大小,叶缘末级脉和叶先端的形态上也存在着差异。据此作者认为岩荠属,泡果荠属和阴山荠属这3属植物分开是合理的,但棒毛荠属的分类地位值得进一步研究。还得出这几个属的叶脉演化关系是;基出完全掌状脉→环结曲行羽状脉→直行羽状脉。  相似文献   

10.
1978年,广西桂林良丰农场的科技人员在四队的1株指柑(1969年定植,仅砧)树上发现一无核变异枝,历经13年的选育,从中选出无核性状稳定、果大、果形端正、色泽鲜艳、丰产性亦好的核柑新品系——桂林良丰无核往柑。经细胞学鉴定,无核柱柑为4X与ZX两种倍数的混倍体,这在桂柑上尚属首例报道”””。我们对杜柑混倍体的形态学和细胞学特性进行了较系统的研究,旨在为今后的进一步选育提供理论基础,为育种实践中的合理应用提供可靠的依据。1材料与方法1.l材料本研究在华中农业大学完成,材料采自广西桂林良丰农场。1.2方法门)树体性状…  相似文献   

11.
独叶草的根和节部及叶的解剖学研究   总被引:7,自引:1,他引:7  
报道了独叶草根、节部和叶的剖解学特征。这些器官在解剖学上表现出的突出点是:根具2个以上的根毛区(与星叶草机相同),中有少量的次生生长,皮层细胞中具内生真菌;变态叶的叶迹或为单迹单维管组织束,或为单迹2维管组织束,或2迹在向皮层外部延伸过程中合并为具2条维管组织束的单迹;叶柄维管束不存在厚壁的维管束鞘,且在由基部向顶部延伸的过程中常发生复杂的分枝及汇合;叶片具有同形的叶肉植物,叶脉维管束鞘具2层细胞  相似文献   

12.
Foster , Adriance S. (U. California, Berkeley), and Howard J. Arnott . Morphology and dichotomous vasculature of the leaf of Kingdonia uniflora. Amer. Jour. Bot. 47 (8): 684–698. Illus. 1960.—An intensive study of the nodal anatomy, petiolar vasculature and open dichotomous venation of the leaf of Kingdonia has revealed a type of foliar vascular system of unusual morphological and phylogenetic interest. The vascular supply at the nodal level consists of 4 collateral traces which diverge from a single gap into the sheathing leaf base. This type of nodal anatomy is perhaps primitive, and comparisons are made with the unilacunar nodes and the 2- and 4-parted leaf trace systems characteristic of many angiospermous cotyledons and the foliage leaves of certain woody ranalian genera. The petiole of Kingdonia is vascularized by 2 pairs of bundles which represent the upward continuation of the 4 leaf traces. A transition from an even (4) to an odd (3) number of strands occurs near the point of attachment of the 5, lobed, cuneiform lamina segments to the petiole. Each of the 2 abaxial bundles dichotomizes and the central derivative branches fuse to form a double bundle which enters the base of the median lamina segment. The 2 adaxial petiolar bundles diverge right and left into the bases of the paired lateral segments of the lamina. An analogous type of transition from an even to an odd number of veins occurs in many angiospermous cotyledons which develop a definable mid-vein. But, in Kingdonia, the bundles which enter the bases of the lamina segments give rise to systems of dichotomizing veinlets devoid of “mid-veins.” Although the majority of the terminal veinlets enter the marginal teeth of the lamina segments, “blind” endings, unrelated to the dentations, occur in all the leaves studied. Typically, all of the vein endings in a given lobule of a lamina segment are derived from the same dichotomous vein system. However, in some leaves, a veinlet dichotomizes directly below a sinus and the branches diverge into the marginal regions of 2 separate lobules. The phylogenetic significance of the occurrence of open dichotomous venation in such an herbaceous angiosperm as Kingdonia is briefly discussed. From a purely morphological viewpoint, the Kingdonia type of venation invites direct comparison with the venation of Sphenophyllum, certain ferns or Ginkgo rather than with any of the known reticulate venation patterns of modern angiosperms. Although the foliar venation of Kingdonia may represent the result of evolutionary reversion, the very rare anastomoses which occur seem primitive in type rather than “vestiges” of a former system of closed venation.  相似文献   

13.
蹄盖蕨科植物叶表皮特征的比较形态学研究   总被引:12,自引:2,他引:10  
对国产蹄盖蕨科18属47种植物的叶表皮特征进行了比较观察,同时选取了5科15属植物作为外类群,对它们的气孔器类型进行了比较。结果表明蹄盖蕨科植物的气孔器类型与近缘的各科植物有明显的区别,叶表皮特征支持将假冷蕨属、峨眉蕨属、短肠蕨属、假蹄盖蕨属、轴果蕨属、网蕨属作为独立属的观点,但不支持将单叶双盖蕨属从双盖蕨属中分出的观点。  相似文献   

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16.
黄杨花单性,雌雄同株,雄花花蜜腺4枚,乳头状,着生于退化雌蕊子房顶部;雌花花蜜腺3枚,短柱状,位于3枚花柱之间。雌、雄花蜜腺均由分泌表皮、产蜜组织和维管束构成,在发育过程中产蜜组织细胞的液泡都发生有规律的变化。雌花蜜腺大,属非淀粉型蜜腺,泌蜜量大,蜜汁含糖分多,维管束中仅含韧皮部;雄花蜜腺小,属淀粉型蜜腺,泌蜜量小.蜜汁含糖量小,维管束由木质部和韧皮部构成。  相似文献   

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After a lag period, rat aortas incubated in rat serum in vitro accumulated substantial quantities of calcium and phosphate. Examination of the tissue by x-ray diffraction, microradiography, electron diffraction, and electron microscopy indicated that the calcium-phosphate phase which formed was hydroxyapatite and that the crystals were localized almost exclusively in elastin. Selective elimination of various components of the aorta with proteolytic enzymes indicated that the presence of elastin was required for mineralization. Collagen fibers did not appear to be required for the initiation of calcification, nor did they seem to undergo appreciable calcification in the time periods studied. Analysis of the initial lag period suggested that at least two changes occurred in serum prior to the mineralization of this tissue. Inhibitors of the reaction were destroyed, and the level of dialyzable calcium was elevated owing to its release from serum protein.  相似文献   

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