Abortion of Spores and Sporangia as a Tool in the Detection of Dryopteris Hybrids
Abortion of Spores and Sporangia as a Tool in the Detection of Dryopteris Hybrids
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DOI：
10.2307/1546429
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发表时间：
1965
影响因子：
0.8
通讯作者：
W. H. Wagner;K. Chen
中科院分区：
文献类型：
--
作者：
W. H. Wagner;K. Chen
蕨类植物的种间和属间杂种，除了极少数例外，都是“不育的”，这实际上是不言自明的。“特雷弗步行者（1958）在某些凤尾蕨属杂交种中发现的情况，仍然是我们种间杂交直接产生可育后代的唯一例子。由于不育性在蕨类植物的杂种中几乎是普遍存在的，因此似乎有必要描述一下这种情况的一些标志。“不育杂交种”的含义需要解释，因为存在一些误解。例如，仅仅缺乏孢子囊群并不一定是杂交的诊断标准。到目前为止，已经确定，蕨类杂交种和正常物种一样有许多孢子囊群。物种和杂交种在生长时都倾向于缺乏孢子囊群，在所涉及的植物不寻常的条件下，例如特别深的阴影和特别潮湿，丰富的基质。关键是，在种间杂交中，孢子囊群和孢子囊的产生本身并不受到抑制，因此，不能自我繁殖的杂种植物仍然可以大量产孢子。一个更严重的问题，如下面将要讨论的起重机（1953）和特里翁（1942）所描述和描绘的所谓的“杂种”，涉及对杂种检测标准的误解。因此，我们希望下面的注释和插图对那些致力于澄清美洲鳞毛蕨属的变异和分类的人有用。
It is practically axiomatic that interspecific and intergeneric hybrids in ferns are, with rare exceptions, "sterile." The situation found by Trevor Walker (1958) in certain hybrids of Pteris remains our only example of interspecific hybridization that yields fertile progeny directly. Because sterility is otherwise so nearly universal among fern hybrids, it seems desirable to describe some of the signposts of this condition. What is meant by "sterile hybrids" requires explanation, because there have been some misunderstandings. The mere absence of sori, for example, is not necessarily diagnostic for hybridity. So far as has been determined, fern hybrids have just as many sori as do normal species. Species as well as hybrids both tend to lack sori when growing, under conditions unusual for the plants involved, such as exceptionally deep shade and especially wet, rich substratum. The point is that production of sori and of sporangia per se are not inhibited in interspecific crosses, so that a hybrid plant which is unable to reproduce itself may nevertheless be abundantly soriferous. A more serious problem, as will be exemplified by alleged "hybrids" described and figured by Crane (1953) and Tryon (1942) to be discussed below, involves misinterpretation of the criteria for the detection of hybrids. We hope, therefore, that the following notes and illustrations will prove useful to those who are engaged in clarifying the variations and taxonomy of American woodferns, Dryopteris.