The series Variantia Ching et S. H. Wu mainly occur in China and its members are highly variable in morphology. The denomination on this group of Asplenium is very confused in the herbaria. We hop e by means of a bios...The series Variantia Ching et S. H. Wu mainly occur in China and its members are highly variable in morphology. The denomination on this group of Asplenium is very confused in the herbaria. We hop e by means of a biosystematic study to find out their genetic relationships in the reticulate evolution, and to raise a suggestion on their taxonomic treatment. Evidence from cytology, allozyme, morphology, and palynology shows that three ancestor diploids have formed Asplenium sarelii complex comprising 13 members. A. sarelii Hook. should be typified as a diploid. The so-called tetraploid 'A. sarelii' before is an allotetraploid that comes from the doubled hybrid between diploid A. sarelii and A. tenuicaule Hayata, which should be treated as a new species A. wudangense Z. R. Wang et X. Hou. A. pekinense Hance is an autotetraploid that comes from the doubled diploid ancestor A. sarelii. A. lushanense C. Chr., a diploid species and the only ancestor of A. yunnariense group, should not been sunk as a synonym of tetraploid A. yunnariense Franch. Most probably, A. varians Wall. ex Hook. et Grev. is an autotetraploid of A. tenuicaule Hayata. Three new natural tetraploid hybrids and their origins have been found out: they are A. x longmenense ( = A. pekinense x varians), A. x jingyunense ( = A. pekinense x yunnanense) and A. x kidoi ( = A. pekinense x wudangense). Three other new natural triploid hybrids have been found and their origins have been inferred: they are A. X huawuense ( = A. sarelii X wudangense), A. x luyunense ( = A. lushanense x yunnanense) and A. x teniuvaians ( = A. tenuicaule x varians). The method of allozyme comparion combined with cytological observation is employed to reveal the complicated relationships among the members of Asplenium sarelii complex in reticulate evolution and proved to be a highly effective tool to investigate the origin of polyploid and hybrid.展开更多
Herbivory with crypsis is not well documented in ferns. The present record of cryptic coloration of coccid Saissetia filicum Boisduval （Homoptera： Coccidae） to the sori of a fern species Asplenium nidus L. （Asplen...Herbivory with crypsis is not well documented in ferns. The present record of cryptic coloration of coccid Saissetia filicum Boisduval （Homoptera： Coccidae） to the sori of a fern species Asplenium nidus L. （Aspleniaceae） is unique. Predatory beetles （Jauravia sp., Coleoptera： Coccinellidae） that feed on the coccids, are suggested to be selective pressure for the development of the present homopteran soral crypsis. A higher rate of effective predation is noticed in the vegetative leaves than the fertile leaves. Aggressive ants were found harvesting honeydew secretions from the coccids and defending the trophobionts as well as the host fern from their natural enemies. In addition, a possible three-way mutualistic relationship among the coccids, its host fern and the tending ant is suggested. Differential numbers of coccids on vegetative and fertile leaves is correlated with their phenol content and degree of predation by beetles. Such coloration mimicry by the coccids may enable them to obtain the necessary blend of sorus of the host fern needed to evade beetle detection and attack.展开更多
Asplenium nidus L. commonly called as Bird’s Nest Fern, is a threatened, ornamental fern, which is widely used as novel foliage ornamental plant and local people use it in worship. The taxon is threatened due to over...Asplenium nidus L. commonly called as Bird’s Nest Fern, is a threatened, ornamental fern, which is widely used as novel foliage ornamental plant and local people use it in worship. The taxon is threatened due to over exploitation, habitat destruction and genetic barriers. To understand the constraints in the regeneration, reproductive biology studies are made. It is observed that more sporophytes are produced in composite population (13.3%) in comparison to isolate population (10%). This pattern is suggestive of the fact that the parental sporophyte is heterozygous for recessive sporophytic lethal. On the basis of the results obtained A. nidus was initially adapted for outbreeding with the capacity for considerable amount of inbreeding. The low potential of sporophyte production in isolate gametophyte could be the constitution of the zygotic genotype.展开更多
Extant Asplenium is one of the most widespread fern groups and occurs in the temperate and tropical regions. However, the fossil records of this genus are poorly documented, especially in the low latitudes. Here, a ne...Extant Asplenium is one of the most widespread fern groups and occurs in the temperate and tropical regions. However, the fossil records of this genus are poorly documented, especially in the low latitudes. Here, a new species, Asplenium sanshuiense sp. nov. is described from the early Eocene of Sanshui Basin, Guangdong Province, South China. This is the lowest modern latitude fossil record of Asplenium and the first fossil assignment of A. section Darea （Jussieu） Bak., as well as the first fossil record of Asplenium reported from South China. This new species shows that Asplenium had already spread into South China by the early Eocene and the section Darea （Jussieu） Bak. was identifiable within the genus Asplenium during that time. This new species, combined with previous fossil spore-pollen records indicates a warm and humid climate in the Sanshui Basin of the early Eocene.展开更多
In the mitochondria and chloroplasts of flowering plants (angiosperms), transcripts of protein-coding genes are altered after synthesis so that their final primary nucleotide sequence differs from that of the correspo...In the mitochondria and chloroplasts of flowering plants (angiosperms), transcripts of protein-coding genes are altered after synthesis so that their final primary nucleotide sequence differs from that of the corresponding DNA sequence. This posttranscriptional mRNA editing consists almost exclusively of C-to-U substitutions (direct) and less frequently of U-to-C substitution (reverse). Editing occurs predominantly within coding regions, mostly at isolated C residues, and usually at first or second positions of codons, thereby almost always changing the amino acid from that specified by the unedited codon. Editing may also create initiation and termination codons. The effect of C-to-U RNA editing in plants is to make proteins encoded by plant organelles more similar in sequence to their non plant homologs, then specific C-to- U editing events are essential for the production of functional plant mitochondrial proteins. Our attention has been devoted to the study of the mRNA editing in cox3 mitochondrial gene of fern Asplenium nidus. This study reveals the extreme importance of both C-to-U and U-to-C substitutions for protein expression.展开更多
文摘The series Variantia Ching et S. H. Wu mainly occur in China and its members are highly variable in morphology. The denomination on this group of Asplenium is very confused in the herbaria. We hop e by means of a biosystematic study to find out their genetic relationships in the reticulate evolution, and to raise a suggestion on their taxonomic treatment. Evidence from cytology, allozyme, morphology, and palynology shows that three ancestor diploids have formed Asplenium sarelii complex comprising 13 members. A. sarelii Hook. should be typified as a diploid. The so-called tetraploid 'A. sarelii' before is an allotetraploid that comes from the doubled hybrid between diploid A. sarelii and A. tenuicaule Hayata, which should be treated as a new species A. wudangense Z. R. Wang et X. Hou. A. pekinense Hance is an autotetraploid that comes from the doubled diploid ancestor A. sarelii. A. lushanense C. Chr., a diploid species and the only ancestor of A. yunnariense group, should not been sunk as a synonym of tetraploid A. yunnariense Franch. Most probably, A. varians Wall. ex Hook. et Grev. is an autotetraploid of A. tenuicaule Hayata. Three new natural tetraploid hybrids and their origins have been found out: they are A. x longmenense ( = A. pekinense x varians), A. x jingyunense ( = A. pekinense x yunnanense) and A. x kidoi ( = A. pekinense x wudangense). Three other new natural triploid hybrids have been found and their origins have been inferred: they are A. X huawuense ( = A. sarelii X wudangense), A. x luyunense ( = A. lushanense x yunnanense) and A. x teniuvaians ( = A. tenuicaule x varians). The method of allozyme comparion combined with cytological observation is employed to reveal the complicated relationships among the members of Asplenium sarelii complex in reticulate evolution and proved to be a highly effective tool to investigate the origin of polyploid and hybrid.
文摘Herbivory with crypsis is not well documented in ferns. The present record of cryptic coloration of coccid Saissetia filicum Boisduval （Homoptera： Coccidae） to the sori of a fern species Asplenium nidus L. （Aspleniaceae） is unique. Predatory beetles （Jauravia sp., Coleoptera： Coccinellidae） that feed on the coccids, are suggested to be selective pressure for the development of the present homopteran soral crypsis. A higher rate of effective predation is noticed in the vegetative leaves than the fertile leaves. Aggressive ants were found harvesting honeydew secretions from the coccids and defending the trophobionts as well as the host fern from their natural enemies. In addition, a possible three-way mutualistic relationship among the coccids, its host fern and the tending ant is suggested. Differential numbers of coccids on vegetative and fertile leaves is correlated with their phenol content and degree of predation by beetles. Such coloration mimicry by the coccids may enable them to obtain the necessary blend of sorus of the host fern needed to evade beetle detection and attack.
文摘Asplenium nidus L. commonly called as Bird’s Nest Fern, is a threatened, ornamental fern, which is widely used as novel foliage ornamental plant and local people use it in worship. The taxon is threatened due to over exploitation, habitat destruction and genetic barriers. To understand the constraints in the regeneration, reproductive biology studies are made. It is observed that more sporophytes are produced in composite population (13.3%) in comparison to isolate population (10%). This pattern is suggestive of the fact that the parental sporophyte is heterozygous for recessive sporophytic lethal. On the basis of the results obtained A. nidus was initially adapted for outbreeding with the capacity for considerable amount of inbreeding. The low potential of sporophyte production in isolate gametophyte could be the constitution of the zygotic genotype.
基金supported by the National Natural Science Foundation of China(Grant No.41210001)the joint Project of the National Natural Science Foundation of China and the Russian Foundation for Basic Research (Grant Nos.41611130044,16-55-53007)+2 种基金the Fundamental Research Funds for the Central Universities (Grant no.161gjc28)State Key Laboratory of Palaeobiology and Stratigraphy(Nanjing Institute of Geology and Palaeontology,CAS)(No.163109)the Scientific Research Fund,Hongda Zhang,Sun Yat-sen University
文摘Extant Asplenium is one of the most widespread fern groups and occurs in the temperate and tropical regions. However, the fossil records of this genus are poorly documented, especially in the low latitudes. Here, a new species, Asplenium sanshuiense sp. nov. is described from the early Eocene of Sanshui Basin, Guangdong Province, South China. This is the lowest modern latitude fossil record of Asplenium and the first fossil assignment of A. section Darea （Jussieu） Bak., as well as the first fossil record of Asplenium reported from South China. This new species shows that Asplenium had already spread into South China by the early Eocene and the section Darea （Jussieu） Bak. was identifiable within the genus Asplenium during that time. This new species, combined with previous fossil spore-pollen records indicates a warm and humid climate in the Sanshui Basin of the early Eocene.
文摘In the mitochondria and chloroplasts of flowering plants (angiosperms), transcripts of protein-coding genes are altered after synthesis so that their final primary nucleotide sequence differs from that of the corresponding DNA sequence. This posttranscriptional mRNA editing consists almost exclusively of C-to-U substitutions (direct) and less frequently of U-to-C substitution (reverse). Editing occurs predominantly within coding regions, mostly at isolated C residues, and usually at first or second positions of codons, thereby almost always changing the amino acid from that specified by the unedited codon. Editing may also create initiation and termination codons. The effect of C-to-U RNA editing in plants is to make proteins encoded by plant organelles more similar in sequence to their non plant homologs, then specific C-to- U editing events are essential for the production of functional plant mitochondrial proteins. Our attention has been devoted to the study of the mRNA editing in cox3 mitochondrial gene of fern Asplenium nidus. This study reveals the extreme importance of both C-to-U and U-to-C substitutions for protein expression.
