Determination of cross-sterile groups in a polymorphic fern Ceratopteris thalictroides

1994年至1995年，从下列11个地点获得了可用的孢子：台湾3个，印度1个，印度尼西亚3个，新几内亚1个，美国夏威夷1个，南美洲苏里金和圭亚那各1个。将这些地区的孢子和冲绳县、千叶县的孢子分别选为南型和北型的代表，播种到琼脂上产生配子体。将发育好的配子体在每个来源内进行自交受精，并在两个日本来源和11个外国来源之间杂交。对孢子体后代进行了PGI和PGM等位酶的电泳分析。通过杂交处理获得196个子代的孢子体后代。其中60个后代不可能被判定为自交或杂交后代，因为亲本孢子体与北方类型和南方类型具有相同的等位酶。等位酶分析表明，在剩余的136个后代中，74个是自交后代，62个是杂交后代。将杂交孢子体的孢子播种到琼脂上。孢子萌发率的高低表明，印度尼西亚有一个孢子源为北型，另外两个可能为南型。台湾的三种孢子来源均为北型，南美洲圭亚那的孢子来源可能为南型。其余的杂交种是北型还是南型，将在它们产生孢子后不久进行检查。目前的研究表明，世界上至少存在两个交叉不育群。

In 1994 to 1995, available spores were obtained from the following 11 localities : three localities in Taiwan, one in India, three in Indonesia, one in New Guinea, one in Hawaii of USA,and each one in Surinum and Guiana in South America. Spores from these localitiesand those from Okinawa Prefecture and Chiba Prefecture, which were selected as the representatives of the south type and the north type of C.thalictroides, respectively, were sown onto agar media to yield gametophytes. Developed gametophytes were conducted to undergo self-fertilization within each source and crossing between two Japanese sources and eleven foreign sources. Electrophoretic analyzes on PGI and PGM allozymes were carried out for sporophyte progeny. Sporophyte progeny of 196 offsprings were obtained through crossing treatment. Out of these, 60 offsprings were impossible to be judged as selfed ones or hybrids, because parental sporophytes had the same allozymes as the north type and the south type. Allozyme analyzes revealed that, of remaining 136 offsprings, 74 were of selfed origin and 62 were of hybrid origin. Spores of hybrid sporophytes were sown onto agar media. The degree of the germination rate of spores indicated that one spore source in Indonesia was of the north type and the other two were probably of the south type. It was also indicated that all the three spore sources of Taiwan were of the north type and the spore source of Guiana of South America was probably of the south type. Whether the remaining hybrids are of the north type or the south type will be checked soon after they will produce spores. The present study suggests that there are at least two cross-sterile groups in C.thalictroides in the world.