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本文通过对半夏属Pinellia 5个种10个群体的染色体计数和珠芽数量统计，首次报道了5个染色体数目，同时发现珠芽的发生与染色体基数及多倍化程度有关：x=13的类群无珠芽，而x=9的有珠芽；在有珠芽的半夏P．ternata(Thunb．)Breit．中，平均每叶珠芽数随倍性的提高而增大。半夏是一个多倍体复合种，起源于无珠芽、染色体基数为x=7～9的二倍体祖先，可能是在该属的早期进化中由鹞落坪半夏P.yaoluopingensis X．H．Guo et X．L.Liu的x=13经非整倍性跌落而成，在发生上比鹞落坪半夏进化。 相似文献
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Owing to the diagnostic characters used for distinguishing Lespedeza bicolor Turcz. from its allies L. formosa (Vogel) Koehne and L. elliptica Benth. ex Maxim. etc. beiny totally quantitative, and the great variability found in themselver as well, the group is therefore regarded as a taxonomically perplexing one. Therefore quantitative measurements of the diagnostic characters, namely, the lengths of flowers (including standards and keels) and calyces (including calyx teeth and tubes) upon the total 307 herbarium sheets collected from 22 provinces and autonomous regions were made, and the data obtained were treated statistically (Table 1) and compared using methods of scatter diagram (Fig. 1--5),polygraph (Fig. 6) and topoclinal variation (Fig. 7--10) in order to bring to light the differentiation pattern of these characters correlated to geographical distribution.
The diagrams of topoclinal variation (Fig. 7--10) of single characters represented by the lengths of calyx-teeth and corolla, or the calyx-teeth/calyx-tube ratio, between which exists a strong positive correlation, show a tendency of increasing gradation from northeast towards south-west. But the different combinations of morphological characters as shown in the scatter diagrams and more particularly in the polygraphs, make it possible to divide the Lespedeza bicolor group into the following three geographical types: (1) Bicolor type, with the distributional area of four provinces and one autonomous region of north-eastern and northern China; having the shortest (shorter than the calyx-rube) calyx-teeth of the whole group; with the standards of 71% herbarium materials exceeding the keels; the corolla length/calyx length ratio being 2.24; (2) Formosa type, with the distributional area covering six provinces and one autonomous region of eastern, south-eastern and southern China; with calyx-teeth nearly as long as calyx-tuges; with the keels of 69% herbarium sheets exceeding the standards, including all from whole Guangdong (Kwantung) and Guangxi (Kwansi); the corolla length/calyx length ratio being 2.59, the largest among the group;
(3) Elliptica type, with the largest distributional area occupying ten provinces of south
western, central, northwestern and eastern China and with most complicated morphologi-
cal variation; the range of calyx-teeth length being 1.23--5.53 mm; with the keels of 80% herbarium sheets exceeding the standards, including all from whole Hubei (Hupeh) and Sichuan ( Szechuan ). Since the above geographical types are either transitional or overlapping, it is probably appropriate to regard them as different geographical subspecies of a single species Lespedeza bicolor Turcz. Taxonomic treatments are then made herewith. A comparison of the main diagnostic characters and distributional patterns of the three subspecies in question is given in Table 3. 相似文献
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在自然界中我们不难发现以下事实：各种动物，特别是昆虫并不是以所有植物作为食物，往往具有“偏食”的特性，有的甚至非常专一。生物学家埃连希(Ehrlich)和雷(Raven)对萝摩科(Asclepiadaceae)及近亲的夹竹桃科(Apocynaceae)植物的研究，发现这些植物能分泌出白色乳汁，内含强心配糖体。这一物质为某些昆虫所厌恶，也为某些灯蛾幼虫所喜爱。 相似文献
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南京两种半夏群体水平变异式样的比较 总被引：1，自引：0，他引：1
南京东郊灵谷寺山坡有一种半夏属Pinellia植物，它外观上与半夏P.ternata相似，但无珠芽；在形态上则更近似鹞落坪半夏P.yaoluopingensis，但缺少子块茎。本文以两个半夏群体和一个鹞落坪半夏(暂名)群体为对象，从生境的调查、形态性状的测量、花粉粒电镜扫描和显微观察以及染色体的计数人手，对两种半夏的变异式样进行比较。结果表明鹞落坪半夏群体与半夏群体的区别在于：(1)营养器官绝无珠芽，佛焰苞檐部边缘决非紫红色，雄花序长度比半夏短，雌花序和附属器长度均比半夏长；(2)花粉粒比半夏小，虽都呈圆球形，但小刺状纹饰较稀疏；(3)染色体2n=26，与半夏群体2n=72不同；(4)半夏具有一定杂草特性，在不同程度人为干扰的环境中能很好地生长和开花。鹞落坪半夏则常见于落叶阔叶林下层未受人为干扰的环境中。 相似文献
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