The mating systems of some epiphytic polypodiaceae
The mating systems of some epiphytic polypodiaceae
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DOI：
10.1640/0002-8444(2002)092
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发表时间：
2002-04-01
影响因子：
0.8
通讯作者：
Ranker, TA
中科院分区：
文献类型：
--
作者：
Chiou, WL;Farrar, DR;Ranker, TA
根据分离配子体培养物的孢子体产量估算的遗传负荷表明，Campyloneurum angustifolium（部分）、C phyllitidis、Phlebodium aureum 和 Phymatosorus scolopendria 配子体内自交交配系统，以及 C. angustifolium（部分）、Microgrammaheterophylla 和 Polypodium pellucidum 配子体间交配系统。多倍体是配子体内自交物种的特征，而配子体间交配类群是二倍体。多倍体类群的重复基因座可能会减轻配子体内自交引起的隐性致死等位基因的表达，而遗传负荷可能维持配子体间交配类群的交配系统。固定杂合性的酶电泳模式支持 C. phyllitidis 和 P. aureum 的异源多倍体起源，并证实了它们的配子体内交配系统。存在于这两个群体中的雌雄异体可以通过促进配子体群体中雄性植物的早期发育来促进二倍体中的配子体交配，并且如果这些配子体延迟或没有达到对它们自己的雌雄异体不敏感的话，则在多倍体的分离配子体中促进两性性。在多倍体中，雄激素也可以通过促进偶尔的异交来减轻低遗传变异性。附生水龙骨科的多年生克隆形成习性增加了单个孢子衍生物的持续时间和占据的物理空间，从而扩大了与后来的迁徙者相互作用的机会。遗传负荷、重复基因和致瘤菌，以及多年生和克隆形成的配子体生长习性，相互作用，产生这些附生物种的成功育种策略。
Genetic loads, estimated from sporophyte production by isolated gametophyte cultures, indicate mating systems of intragametophytic selfing in Campyloneurum angustifolium (in part), C phyllitidis, Phlebodium aureum and Phymatosorus scolopendria, and intergametophytic mating in C. angustifolium (in part), Microgramma heterophylla and Polypodium pellucidum. Polyploidy characterizes the intragametophytic-selfing species, whereas the intergametophytic-mating taxa are diploid. The duplicated loci of polyploid taxa may mitigate the expression of recessive lethal alleles caused by intragametophytic selfing, whereas genetic load probably maintains the mating systems of the intergametophytically mating taxa. Enzyme electrophoretic patterns of fixed heterozygosity support allopolyploid origins of C. phyllitidis and P. aureum and confirm their intragametophytic mating systems. Antheridiogens, present in both groups, may promote intergametophytic mating in diploids through promotion of the early development of male plants in gametophyte populations and bisexuality in isolated gametophytes of polyploids if these gametophytes delay or do not attain insensitivity to their own antheridiogen. In the polyploids, antheridiogens may also alleviate low genetic variability through promotion of occasional outcrossing. The perennial, clone-forming habit of epiphytic Polypodiaceae increases the duration and the physical space occupied by derivatives of a single spore, thus expanding the chance of interaction with a later migrant. Genetic load, duplicated genes, and antheridiogens, together with a perennial and clone-forming gametophyte growth habit, interact to produce successful breeding strategies of these epiphytic species.