APOMIXIS IN PANICUM MAXIMUM
APOMIXIS IN PANICUM MAXIMUM
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最大黍无融合生殖
DOI：
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发表时间：
1954
期刊：
影响因子：
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通讯作者：
H. E. Warmke
中科院分区：
文献类型：
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作者：
H. E. Warmke
在最近对天竺葵（Panicum maximum Jacq.）的细胞分类学研究中观察到一些有性生殖中断或旁路的迹象。来自波多黎各。本种为同源四倍体，小孢子发生过程中减数分裂不规则，染色体不分离，实验种植的幼苗后代非常均匀;从五个品种混合的植株中收集的自由授粉种子未能产生可识别的杂种（Warmke，1951）。这些特征强烈地暗示了无融合生殖的发生。本细胞学研究的生殖过程中的女性进行，以确定是否无融合生殖发生，如果是这样，其程度和机制。由于涉及无融合生殖的性过程的各种变化，以及关于这个问题的术语和广泛的文献，在最近的综述中已经得到了充分的处理（Stebbins，1941，和Gustafsson，1946，1947 a，B），读者可以参考这些综述。胚乳在种子发育中的作用也一直是广泛综述的主题（Brink和库珀，1947）。材料和方法。几内亚草，Panicumn最大变种。普通几内亚是本研究的主要材料来源。品种gramalote，宽叶，细叶，和Borinquen（Warmke，1951）被用作补充材料，并注意到任何重要的差异，从普通几内亚。所需年龄的花序取自田间生长的植物，并直接带到实验室进行固定。对于开花前的阶段，切下颖片，用细剪刀去除可育小花的外稃和内稃的远端1/3，以允许杀死液快速进入子房。对于开花后的阶段，如上所述杀死小花，然后在辅助下在低倍双筒望远镜下从子房移除整个外稃和内稃。解剖针这些结构，这是硬结在这个物种，被删除，以方便切片。杀死主要是在福尔马林-醋酸-酒精（70%酒精）中进行的，小花用正丁醇法包埋在石蜡中。切片切成15 μ厚，用铁-苏木精和番红-浅绿色组合染色。前者被发现上级的大多数阶段，特别是那些涉及受精。
INDICATIONS OF SOME break-down or by-pass of sexual reproduction were observed in recent cytotaxonomic studies of guinea grass (Panicum maximum Jacq.) from Puerto Rico. In this species, which is autotetraploid and characterized by considerable meiotic irregularity and chromosome nondisjunction in microsporogenesis, seedling progenies in experimental plantings were found to be extremely uniform; and open-pollinated seed collected from plants of five varieties intermixed failed to yield recognizable hybrids (Warmke, 1951). These pecularities strongly suggested the occurrence of apomixis. The present cytological studies of the reproductive processes on the female side were undertaken to determine whether apomixis occurs, and if so, its extent and the mechanisms involved. Since the various modifications of the sexual process involved in apomixis, as well as the terminology and extensive literature on this subject, have been adequately treated in recent reviews (Stebbins, 1941, and Gustafsson, 1946, 1947a,b), the reader is referred to these reviews. The role of the endosperm in seed development also has been the subject of an extensive review (Brink and Cooper, 1947). MATERIALS AND METHODS.-Guinea grass, Panicumn maximum var. common guinea, was the main source of material for the present studies. The varieties gramalote, broad-leaf, fine-leaf, and Borinquen (Warmke, 1951) were used as supplementary material, and any important differences from common guinea were noted. Inflorescences of the desired ages were taken from field-grown plants and were brought directly to the laboratory for fixation. For stages prior to anthesis, the glumes were dissected off, and the distal 1/3 of the lemma and palea of fertile florets was removed with fine scissors to permit rapid entrance of the killing fluid to the ovary. For stages after anthesis, florets were killed as described above, and then the entire lemma and palea were removed from the ovary under a low-power binocular with the aid. of dissecting needles. These structures, which are indurated in this species, were removed to facilitate sectioning. Killing was done principally in formalin-acetic-alcohol (70 per cent alcohol), and the florets were embedded in paraffin, using the normal-butyl alcohol method. Sections were cut 15,u in thickness and were stained in iron-hematoxylin and in a safranin-light green combination. The former was found superior for most stages, especially those involving fertilization.