| 中国凤尾蕨属细胞学的初步研究 |
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| 引用本文： | 王中仁.中国凤尾蕨属细胞学的初步研究[J].中国科学院研究生院学报,1989,27(6):421-438. |
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| 作者姓名： | 王中仁 |
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| 作者单位： | (中国科学院植物研究所系统与进化植物学开放实验室，北京) |
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| 摘 要： | 本文报道了中国产10种凤尾蕨属植物和2种蕨属和栗蕨属植物的细胞学研究结果。 在凤尾蕨
属中，8种是多倍体或具有多倍体细胞型，4种是无性孢子繁殖的后代，6种实际上是种复合体或种复合
体成员，单纯有性生殖的二倍体只有2种。凤尾蕨至少具有9条孢子发生路线，在其同一个体上除了产
生二倍孢子外，还可能产生少量加倍或多倍孢子；广义的蜈蚣草实际上是个种复合体，其祖先的二倍体
细胞型广泛分布于中国亚热带地区说明这里可能是该复合体的起源中心；岩凤尾蕨具有不寻常的染色 体数目n＝55，这说明在本属和本科中可能存在着非整倍体进化。
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| 关 键 词： | 蕨类植物 凤尾蕨属 染色体数目 孢子发生 无性孢子繁殖 多倍体 |
A Preliminary Study on Cytology of Chinese Pteris |
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| Wang Zhong-Ren.A Preliminary Study on Cytology of Chinese Pteris[J].Journal of the Graduate School of the Chinese Academy of Sciences,1989,27(6):421-438. |
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| Authors: | Wang Zhong-Ren |
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| Institution: | (laboratory of Systematic and Evolutionary Botany, Academia Sinica, Beijing) |
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| Abstract: | Cytological and biosystematic studies on the genus Pteris have made a great
contribution to the theory of speciation and evolution in ferns. Sino-Japanese area is one of the
speciation centers of this genus. But only a few Chinese species have been known cytologically.
As a preliminary study, ten species of the genus Pteris and two species of the related genera
Pteridium and Histiopteris were observed. All the materials were collected from southwest
and south China. Their young sori were fixed in ethanol and glacial acetic acid (3:1), in the
field. The preparations were made with acetocarmine squash method. The vouchers are de-
posited in PE.
The results of observation are summarized in Table 1. Of Pteris, four species are agamosp-
orous, eight are polyploid, six are actually the members of species complexes. Only two species
are purely sexual diploids.
Pteris cretica L. var. nervosa (Thunb.) Ching et S. H. Wu has 58 autobivalents at meiosis
of spore mother cell, and usually produces 32 diplospores per sporangium. It is obviously an
agamosporous diploid. Apart from 32-spored sporangium, some 4-, 8-, 16-, 64-, 13-, 34-, 36-
spored, completely abortive or partly abortive sporangia were also found in the fixed material
of a single individual. For explaining these unusual types of sporangia at least nine sporo-
genesis routes can be inferred. It may not be impossible that besides mainly producing func-
tional diplospores, P. cretica var. nervosa also gives a few functional giant spores with a doubled
or multiplied somatic chromosome number, which means that polyploids may be simply derived
from the spores produced by their diploid parent. The spores in a sporangium are usually
tetrahedral, but a few bilateral ones are also found in some sporangia. Sometimes, the bila-
teral spores are even more than the tetrahedral ones in a sporangium.
Pteris vittata L. from the type locality shows 58 bivalents at diakinesis of meiosis. Without
doubt, it is a sexual tetraploid, which was also found in south Guangdong and south Yunnan.
However, Its natural ancestral diploid has been widely found in the subtropical regions of
China, such as Sichuan, Guizhou, Yunnan and Hubei provinces. A sterile triploid with the
chromosome number of n=201Ⅰ+26Ⅱ+5Ⅲ and a sterile tetraploid hybrid with the chromosome
number of n=9Ⅰ+45Ⅱ+3Ⅲ+21Ⅴ were found in south Yunnan and south Guangdong respec-
tively. It is evident that P. vittata L. sensu lato is a species complex which includes several cy-
totypes. Its hexaploid form was reported from south India by Abraham et al. The distribu-
tion pattern of different cytotypes in P. vittata complex may indicate that the tropics is more
favourable to formation and surviving of polyploid than the subtropics. However, it is most
possible that Chinese subtropics is the origin place of the ancestral member in the P. vittata
complex. In gross morphology, the tetraploid and triploid forms are only bigger and stronger
than the diploid form. But the diploid can also grow rather big in cultivation. They can har-
dly be distinguished from each other. Therefore, they are not given formal names here. The
author fully agree with Prof. T. Reichstein when he said in 1983 that it was hoped that a new
nomenclature could be adopted for the cytotypes of species complex in future.
The special chromosome number of Pteris deltodon Bak .was counted in this work for the
first time. It has 55 bivalents at meiosis of SMC. This number is the only exception in the
genus Pteris, and shows that aneuploidy may have taken place in this genus. However, the pos-
sibility can not be ruled out that P. deltodon is an allotetraploid came from two diploid spe-
cies respectively with the chromosome number 26 and 29.
Pteris gallinopes described by Prof. Ching in i983 is an agamosporous tetraploid with 116
autobivalents at meiosis, different from the related triploid species P. dactylina Hook. and P.
henryi Christ.
P. ensiformis Burm。 P. muftifida Poir. and P. semipinnata L. are sexual tetraploids with
n=58. P. excelsa Gaud. and P. oshimensis Hieron. var. paraemeiensis Ching are agamosporous
triploids with n = 87 autobivalents. P. wallichiana Agardh is a sexual diploid with n=29.
The high frequency of polyploids and agamospory among these random sampled Chinese
species futher confirms the conclusion that both polyploidy and apomixis have played an im-
portant role in speciation and evolution of the genus Pteris.
Pteridium aquilimum (L.) Kunh var. latiusculum (Desv.) Underw. ex Heller and His-
tiopteris incisa (Thunb.) J. Sm. have n=52 and n=96 respectively. They are both sexual te-
traploids. Their chromosome numbers show again that the genera Pteridium and Histiopteris
are distinquished from the genus Pteris by different basic numbers.
This project is supported by the National Natural Science Foundation of China. |
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