Techniques of tracking movements of pollen grains are essential for many topics in pollination biology. Pollen transfer of Liriodendron chinense(Hemsl.) Sarg., a hermaphroditic plant, may be both interfloral and intra...Techniques of tracking movements of pollen grains are essential for many topics in pollination biology. Pollen transfer of Liriodendron chinense(Hemsl.) Sarg., a hermaphroditic plant, may be both interfloral and intrafloral pollination. Observations on pollinator movements and flower emasculated experiments in natural populations showed that most of pollen grains deposited on stigmas in a flower are foreign. But it is not certain whether cross pollination or long distance pollen transfer occurs in this insect-pollinated plant. The authors attempt to use random amplified polymorphic DNA (RAPD) loci for paternity analysis to mark pollen dispersal. The results indicated pollen via gene transportation reached at least 100 m away from the pollen source in a selected population. The primary study suggests a larger effective population size in this endangered plant. With its rapid and simple characters, RAPD methods can be a suitable technique for marking pollen flow and able to be widely used in various taxa.展开更多
Patterns of gene flow and gene introgres sion can be used to assess the risk of genetic pollution of wild forest trees from widespread cultivated trees.A comprehensive understanding of the genetic relationships and le...Patterns of gene flow and gene introgres sion can be used to assess the risk of genetic pollution of wild forest trees from widespread cultivated trees.A comprehensive understanding of the genetic relationships and levels of gene flow among wild and cultivated common walnut(Juglans regia)has become an urgent issue.Using twelve microsatellite markers,we investigated the genetic diversity and gene flow between cultivated and wild trees of J.regia in the Qinling Mountains,China.A high level of genetic variation was detected in both cultivated and wild trees.The mean number of alleles per locus was 17.5.Observed heterozygosity(HO)and expected heterozygosity(HE)were 0.777 and 0.800,respectively.Pollination of mother trees was not by nearest neighbors,and a paternity of 60.7%of offspring evaluated could not be assigned to a local,sampled tree.Pollen flow from cultivated trees to wild trees was infrequent(5.4%),and selfing rates ranged from zero to 25.0%.Male parents were located from 0 to 1005 m from their female partners,with an average pollination distance of 285.1 m.These results are discussed in light of the cultivated species’diversity,outlining the frequent spontaneous genetic contributions from the wild to the cultivated compartment.In addition,the pollen flow parameters provide useful information about the dynamics of pollen movement within J.regia populations.展开更多
Male components of the reproduction process in Pinus roxburghii were investigated for their variation in time and space as well as pollination, viz. flowering phenology, pollen production variability and pollen disper...Male components of the reproduction process in Pinus roxburghii were investigated for their variation in time and space as well as pollination, viz. flowering phenology, pollen production variability and pollen dispersal, for five successive years at two different locations （at the lower and higher elevations）. The study reveals that elevation and the hour of the day are the main determi- nants of anthesis and microsporangium dehiscence, because both are related to temperature and humidity. The receptivity of ovulate cone strobili or female strobili occurred earlier at the lower elevation than at the higher elevation, with a longer receptivity period in the latter case. The phenology of male and female cones varied significantly between years and elevations. The determinations of pol- len yield considered various sources of variability, i.e., the number of pollen strobili per branch, strobili per tree, microsporangia per tree and pollen grains per tree. Each of these parameters revealed significant year-to-year and elevation effects. Year-to-year varia- tion in the production of pollen cone and pollen grains with mass production after a three-year period revealed a three-year cycle of masting in pollen production in P. roxburghii. The pollen dispersal decreased quickly with distance from the pollen source. As a con- sequence, a distance of 600 m was proposed as a minimum to prevent contamination by pollen in the management of seed orchards. The results ultimately suggest that the ample production of pollen grains per tree along with flowering synchrony and long dispersal of pollen grains results in homogeneity in large populations.展开更多
文摘Techniques of tracking movements of pollen grains are essential for many topics in pollination biology. Pollen transfer of Liriodendron chinense(Hemsl.) Sarg., a hermaphroditic plant, may be both interfloral and intrafloral pollination. Observations on pollinator movements and flower emasculated experiments in natural populations showed that most of pollen grains deposited on stigmas in a flower are foreign. But it is not certain whether cross pollination or long distance pollen transfer occurs in this insect-pollinated plant. The authors attempt to use random amplified polymorphic DNA (RAPD) loci for paternity analysis to mark pollen dispersal. The results indicated pollen via gene transportation reached at least 100 m away from the pollen source in a selected population. The primary study suggests a larger effective population size in this endangered plant. With its rapid and simple characters, RAPD methods can be a suitable technique for marking pollen flow and able to be widely used in various taxa.
基金supported by Qinling National Forest Ecosystem Research StationNational Natural Science Foundation of China(Nos.31200500,41471038,and 32070372)+2 种基金Shaanxi Academy of Science Research Funding Project(Y19Z604F12)Natural Science Foundation of Shaanxi Province of China(2019JM-008)the public health specialty in the department of traditional Chinese Medicine(2017-66,2018-43,2019-68)。
文摘Patterns of gene flow and gene introgres sion can be used to assess the risk of genetic pollution of wild forest trees from widespread cultivated trees.A comprehensive understanding of the genetic relationships and levels of gene flow among wild and cultivated common walnut(Juglans regia)has become an urgent issue.Using twelve microsatellite markers,we investigated the genetic diversity and gene flow between cultivated and wild trees of J.regia in the Qinling Mountains,China.A high level of genetic variation was detected in both cultivated and wild trees.The mean number of alleles per locus was 17.5.Observed heterozygosity(HO)and expected heterozygosity(HE)were 0.777 and 0.800,respectively.Pollination of mother trees was not by nearest neighbors,and a paternity of 60.7%of offspring evaluated could not be assigned to a local,sampled tree.Pollen flow from cultivated trees to wild trees was infrequent(5.4%),and selfing rates ranged from zero to 25.0%.Male parents were located from 0 to 1005 m from their female partners,with an average pollination distance of 285.1 m.These results are discussed in light of the cultivated species’diversity,outlining the frequent spontaneous genetic contributions from the wild to the cultivated compartment.In addition,the pollen flow parameters provide useful information about the dynamics of pollen movement within J.regia populations.
文摘Male components of the reproduction process in Pinus roxburghii were investigated for their variation in time and space as well as pollination, viz. flowering phenology, pollen production variability and pollen dispersal, for five successive years at two different locations （at the lower and higher elevations）. The study reveals that elevation and the hour of the day are the main determi- nants of anthesis and microsporangium dehiscence, because both are related to temperature and humidity. The receptivity of ovulate cone strobili or female strobili occurred earlier at the lower elevation than at the higher elevation, with a longer receptivity period in the latter case. The phenology of male and female cones varied significantly between years and elevations. The determinations of pol- len yield considered various sources of variability, i.e., the number of pollen strobili per branch, strobili per tree, microsporangia per tree and pollen grains per tree. Each of these parameters revealed significant year-to-year and elevation effects. Year-to-year varia- tion in the production of pollen cone and pollen grains with mass production after a three-year period revealed a three-year cycle of masting in pollen production in P. roxburghii. The pollen dispersal decreased quickly with distance from the pollen source. As a con- sequence, a distance of 600 m was proposed as a minimum to prevent contamination by pollen in the management of seed orchards. The results ultimately suggest that the ample production of pollen grains per tree along with flowering synchrony and long dispersal of pollen grains results in homogeneity in large populations.
