2014 Vol. 32 No. 4
2014, 32(4): 315-319.
DOI: 10.3724/SP.J.1142.2014.40315
Abstract：
Dry pollen grains of Asimina longifolia var. spatulata, A. reticulata, and Disepalum plagioneurum were described based on scanning electron microscopy to provide evidence for phylogenetic analysis. Results showed that most pollen grains were tetrads. Occasionally,dyads and triads were found in A. reticulata,and polyads were also observed in D. plagioneurum. Most of the tetrads were rhomboidal tetrads,though tetragonal tetrads were also observed in A. reticulata and D. plagioneurum. The ornamentations of the pollen walls were regulate (A. longifolia var. spatulata),microreticulate (A. reticulata) or reticulate (D. plagioneurum). Pollen grains of neighboring tetrads were connected by either short exine connections or pollen-connecting threads. The function of the cohesion among tetrads was to enhance pollination efficiency by enabling fertilization of multiple ovules in a single pollinator visit. Wall ornamentation and tetrad pollen grains in Asimina were similar with those of Disepalum,which supports their close phylogenetic relationship.
Dry pollen grains of Asimina longifolia var. spatulata, A. reticulata, and Disepalum plagioneurum were described based on scanning electron microscopy to provide evidence for phylogenetic analysis. Results showed that most pollen grains were tetrads. Occasionally,dyads and triads were found in A. reticulata,and polyads were also observed in D. plagioneurum. Most of the tetrads were rhomboidal tetrads,though tetragonal tetrads were also observed in A. reticulata and D. plagioneurum. The ornamentations of the pollen walls were regulate (A. longifolia var. spatulata),microreticulate (A. reticulata) or reticulate (D. plagioneurum). Pollen grains of neighboring tetrads were connected by either short exine connections or pollen-connecting threads. The function of the cohesion among tetrads was to enhance pollination efficiency by enabling fertilization of multiple ovules in a single pollinator visit. Wall ornamentation and tetrad pollen grains in Asimina were similar with those of Disepalum,which supports their close phylogenetic relationship.
2014, 32(4): 320-328.
DOI: 10.3724/SP.J.1142.2014.40320
Abstract：
Plant leaves reach water balance by evaporative water loss through stomata and water supply from leaf veins. However,it is still unclear whether water supply and transpiration demand maintained balance during the evolution of basal angiosperms. In the present study,we measured stomatal density,stomatal length,vein density and leaf thickness from 11 basal angiosperm species and applied phylogenetically independent contrasts,combined with phylogenetic trees,to detect correlated-evolution between traits. Our results showed that along the evolutionary direction,stomatal density and vein density increased gradually while stomatal length and leaf thickness expressed a declining trend; whether phylogeny was considered or not,stomatal density was positively correlated with vein density,indicating their correlated-evolution,and supporting the hypothesis that leaf water balance existed in basal angiosperms; leaf thickness was correlated significantly with both stomatal traits and vein density; however,after removing the phylogenetic effect,these correlations disappeared,indicating non-correlated evolution between these traits. The results of the present study revealed that the maintenance of the balance between water demand and supply,and even CO2 supply,drove the evolution of leaf structure and function in basal angiosperms.
Plant leaves reach water balance by evaporative water loss through stomata and water supply from leaf veins. However,it is still unclear whether water supply and transpiration demand maintained balance during the evolution of basal angiosperms. In the present study,we measured stomatal density,stomatal length,vein density and leaf thickness from 11 basal angiosperm species and applied phylogenetically independent contrasts,combined with phylogenetic trees,to detect correlated-evolution between traits. Our results showed that along the evolutionary direction,stomatal density and vein density increased gradually while stomatal length and leaf thickness expressed a declining trend; whether phylogeny was considered or not,stomatal density was positively correlated with vein density,indicating their correlated-evolution,and supporting the hypothesis that leaf water balance existed in basal angiosperms; leaf thickness was correlated significantly with both stomatal traits and vein density; however,after removing the phylogenetic effect,these correlations disappeared,indicating non-correlated evolution between these traits. The results of the present study revealed that the maintenance of the balance between water demand and supply,and even CO2 supply,drove the evolution of leaf structure and function in basal angiosperms.
2014, 32(4): 329-335.
DOI: 10.3724/SP.J.1142.2014.40329
Abstract：
Isodon atroruber R. A. Clement,collected from Cuona County in Tibet,is a new record for China. The species is described and illustrated here. Scanning electron microscopy and light microscopy are carried out to examine the micromorphology of the leaf epidermis,pollen,and mericarp of the species. A key to 19 taxa of Isodon distributed in Tibet is also provided.
Isodon atroruber R. A. Clement,collected from Cuona County in Tibet,is a new record for China. The species is described and illustrated here. Scanning electron microscopy and light microscopy are carried out to examine the micromorphology of the leaf epidermis,pollen,and mericarp of the species. A key to 19 taxa of Isodon distributed in Tibet is also provided.
2014, 32(4): 336-339.
DOI: 10.3724/SP.J.1142.2014.40336
Abstract：
Diplazium × kidoi Sa.Kurata is a natural hybrid species between D. wichurae (Mett.) Diels and D. pinfaense Ching,which was only known in Japan. Two populations of the hybrid from China are reported for the first time in this paper,and detailed morphological comparison to its parents is also provided. The discovery of D.× kidoi in China will be helpful to understand the allopatric speciation of hybrids and cognize the common phenomenon of hybridization along with speciation of ferns.
Diplazium × kidoi Sa.Kurata is a natural hybrid species between D. wichurae (Mett.) Diels and D. pinfaense Ching,which was only known in Japan. Two populations of the hybrid from China are reported for the first time in this paper,and detailed morphological comparison to its parents is also provided. The discovery of D.× kidoi in China will be helpful to understand the allopatric speciation of hybrids and cognize the common phenomenon of hybridization along with speciation of ferns.
2014, 32(4): 340-354.
DOI: 10.3724/SP.J.1142.2014.40340
Abstract：
Based on the identification of about 4000 specimens collected from Mountain Kunyu,Shandong,China,318 species in 131 genera and 56 families were identified,among which 41 species in 28 genera and 22 families were liverworts,while 277 species in 103 genera and 34 families were mosses. Sixty nine species were new records for Shandong province. Dominant families included Brachytheciaceae (45 spp.),Bryaceae (33 spp.),Pottiaceae (31 spp.),Hypnaceae (24 spp.),Entodontaceae (18 spp.) and Dicranaceae (15 spp.). The monotypic and oligotypic genera were rich,but there were few endemic species. In terms of habitat preferance,geophytia and petrophytia made up the majority of the bryoflora,while hydrophytia and epixylophytia were few. Distribution patterns were varied. The temperate pattern was dominant,while some tropical elements also occurred. This study was designed to develop and progress bryophyte research in Shandong Province in order to achieve the pace of modern bryology. This study can provide new material for bryophyte study in China.
Based on the identification of about 4000 specimens collected from Mountain Kunyu,Shandong,China,318 species in 131 genera and 56 families were identified,among which 41 species in 28 genera and 22 families were liverworts,while 277 species in 103 genera and 34 families were mosses. Sixty nine species were new records for Shandong province. Dominant families included Brachytheciaceae (45 spp.),Bryaceae (33 spp.),Pottiaceae (31 spp.),Hypnaceae (24 spp.),Entodontaceae (18 spp.) and Dicranaceae (15 spp.). The monotypic and oligotypic genera were rich,but there were few endemic species. In terms of habitat preferance,geophytia and petrophytia made up the majority of the bryoflora,while hydrophytia and epixylophytia were few. Distribution patterns were varied. The temperate pattern was dominant,while some tropical elements also occurred. This study was designed to develop and progress bryophyte research in Shandong Province in order to achieve the pace of modern bryology. This study can provide new material for bryophyte study in China.
2014, 32(4): 355-361.
DOI: 10.3724/SP.J.1142.2014.40355
Abstract：
To study species composition and community structure of typical subtropical evergreen broad-leaved forest (EBLF) and subtropical montane elfin forest (MELF), we established 1 hm2 EBLF plots and 1 hm2 MELF plots in Shimentai National Nature Reserve in Guangdong, South China. Using all woody plants with DBH ≥ 1 cm, including trees, shrubs and lianas in each plot, the species composition and community structure of the plots were analyzed based on species community, density, diameter at breast height (DBH) class structure and plant height structure of the area. Results showed that dominant species differed between EBLF and MELF, with a Srensen similarity index value of 0.41, but dominant families (Theaceae and Ericaceae) were similar. The mean densities of seedlings (1 cm ≤ DBH < 2.5 cm) and saplings (2.5 cm ≤ DBH < 12.5 cm) were lower in EBLF than those in MELF, while there were no differences in density of small trees (12.5 cm ≤ DBH < 25 cm) and adult trees (DBH ≥ 25 cm) between the two forest types. EBLF had higher mean DBH of seedlings and adult trees, but lower mean DBH of saplings than those of MELF, while there were no differences in mean DBH of small trees between the two forest types. Mean height of small trees and adult trees were higher and mean height of seedlings were lower in EBLF than those in MELF, but there were no differences in mean height of saplings between the two forest types. Our results highlight the differences in community structure and species diversity between EBLF and MELF, which likely resulted from differences in structure and diversity maintenance mechanisms of these two forest types, with EBLF being more stable than MELF.
To study species composition and community structure of typical subtropical evergreen broad-leaved forest (EBLF) and subtropical montane elfin forest (MELF), we established 1 hm2 EBLF plots and 1 hm2 MELF plots in Shimentai National Nature Reserve in Guangdong, South China. Using all woody plants with DBH ≥ 1 cm, including trees, shrubs and lianas in each plot, the species composition and community structure of the plots were analyzed based on species community, density, diameter at breast height (DBH) class structure and plant height structure of the area. Results showed that dominant species differed between EBLF and MELF, with a Srensen similarity index value of 0.41, but dominant families (Theaceae and Ericaceae) were similar. The mean densities of seedlings (1 cm ≤ DBH < 2.5 cm) and saplings (2.5 cm ≤ DBH < 12.5 cm) were lower in EBLF than those in MELF, while there were no differences in density of small trees (12.5 cm ≤ DBH < 25 cm) and adult trees (DBH ≥ 25 cm) between the two forest types. EBLF had higher mean DBH of seedlings and adult trees, but lower mean DBH of saplings than those of MELF, while there were no differences in mean DBH of small trees between the two forest types. Mean height of small trees and adult trees were higher and mean height of seedlings were lower in EBLF than those in MELF, but there were no differences in mean height of saplings between the two forest types. Our results highlight the differences in community structure and species diversity between EBLF and MELF, which likely resulted from differences in structure and diversity maintenance mechanisms of these two forest types, with EBLF being more stable than MELF.
2014, 32(4): 362-370.
DOI: 10.3724/SP.J.1142.2014.40362
Abstract：
Lianas are abundant in tropical rainforest. With global climate change, liana density and biomass are increasing. This can significantly influence co-occurring tree recruitment, growth, mortality and survival, which, in turn, may have a significant effect on the structure, functioning and dynamics of tropical forests. In this study, we measured 17 leaf traits of 20 tropical rainforest liana species from 13 families and analyzed trait associations across lianas. Our results showed that relative water content of liana leaves exhibited the smallest interspecific variation, with a coefficient of variation (CV) of 5%, adaxial epidermis thickness presented the largest interspecific variation (CV of 80%), with the CV of the other 15 traits ranging from 24% to 61%. Across the lianas studied, both vein density and leaf density were positively correlated with stomatal density; and, specific leaf area was negatively correlated with leaf dry matter content. Compared with trees growing in the same habitats, lianas had lower values for leaf area, stomatal density and leaf density, but higher specific leaf area, with no significant differences in leaf anatomical traits between lianas and trees. These results are essential for understanding the ecological adaptation of lianas in tropical rainforest.
Lianas are abundant in tropical rainforest. With global climate change, liana density and biomass are increasing. This can significantly influence co-occurring tree recruitment, growth, mortality and survival, which, in turn, may have a significant effect on the structure, functioning and dynamics of tropical forests. In this study, we measured 17 leaf traits of 20 tropical rainforest liana species from 13 families and analyzed trait associations across lianas. Our results showed that relative water content of liana leaves exhibited the smallest interspecific variation, with a coefficient of variation (CV) of 5%, adaxial epidermis thickness presented the largest interspecific variation (CV of 80%), with the CV of the other 15 traits ranging from 24% to 61%. Across the lianas studied, both vein density and leaf density were positively correlated with stomatal density; and, specific leaf area was negatively correlated with leaf dry matter content. Compared with trees growing in the same habitats, lianas had lower values for leaf area, stomatal density and leaf density, but higher specific leaf area, with no significant differences in leaf anatomical traits between lianas and trees. These results are essential for understanding the ecological adaptation of lianas in tropical rainforest.
2014, 32(4): 371-382.
DOI: 10.3724/SP.J.1142.2014.40371
Abstract：
Lepidium perfoliatum, an annual herb plant species of Brassicaceae, has a typical myxospermy. The TTG1 (Transparent testa glabra 1) gene encodes a putative transcription factor, which has been identified to play a role in epidermal cell differentiation and mucilage release. Till now, research on the TTG1 gene in myxospermy plants has been rarely reported. To identify TTG1 gene function, mucilage related gene LpTTG1 from L. perfoliatum was cloned in the present study. The full length ORF of the TTG1 gene from L. perfoliatum was isolated by homologous cloning, and was found to be 1032 bp long, encoded 343 putative amino acids and contained WD40 motifs, named as LpTTG1. The qRT-PCR results showed that LpTTG1 was widely expressed in different tissues of L. perfoliatum, which may reflect diverse functions of LpTTG1. Moreover, immunolocalization analysis indicated that the expression of LpTTG1 changed in inner and outer integuments and corresponded to the synthesis of mucilage in outer integument cell layers, suggesting that LpTTG1 mainly regulates the development of the seed coat then applies the effect on mucilage production. Furthermore, overexpression of LpTTG1 in Arabidopsis could significantly enhance the expression of AtMUM4 (which developmentally regulates mucilage production downstream) in silique, which means LpTTG1 attends to the mucilage regulation pathway and generates more downstream product-MUM4 in promotion of mucilage synthesis. In our experiment, however, no significant difference in seed morphology and release pattern, or the secretion amount of mucilage between LpTTG1 overexpression transgenic line and WT, was observed. One possible explanation may be that mucilage synthesis and release is a complex process in Arabidopsis, and is regulated by many genes with functional redundancy, therefore increasing the transcription level with one of them during development may not result in significant phenotype change.
Lepidium perfoliatum, an annual herb plant species of Brassicaceae, has a typical myxospermy. The TTG1 (Transparent testa glabra 1) gene encodes a putative transcription factor, which has been identified to play a role in epidermal cell differentiation and mucilage release. Till now, research on the TTG1 gene in myxospermy plants has been rarely reported. To identify TTG1 gene function, mucilage related gene LpTTG1 from L. perfoliatum was cloned in the present study. The full length ORF of the TTG1 gene from L. perfoliatum was isolated by homologous cloning, and was found to be 1032 bp long, encoded 343 putative amino acids and contained WD40 motifs, named as LpTTG1. The qRT-PCR results showed that LpTTG1 was widely expressed in different tissues of L. perfoliatum, which may reflect diverse functions of LpTTG1. Moreover, immunolocalization analysis indicated that the expression of LpTTG1 changed in inner and outer integuments and corresponded to the synthesis of mucilage in outer integument cell layers, suggesting that LpTTG1 mainly regulates the development of the seed coat then applies the effect on mucilage production. Furthermore, overexpression of LpTTG1 in Arabidopsis could significantly enhance the expression of AtMUM4 (which developmentally regulates mucilage production downstream) in silique, which means LpTTG1 attends to the mucilage regulation pathway and generates more downstream product-MUM4 in promotion of mucilage synthesis. In our experiment, however, no significant difference in seed morphology and release pattern, or the secretion amount of mucilage between LpTTG1 overexpression transgenic line and WT, was observed. One possible explanation may be that mucilage synthesis and release is a complex process in Arabidopsis, and is regulated by many genes with functional redundancy, therefore increasing the transcription level with one of them during development may not result in significant phenotype change.
2014, 32(4): 383-393.
DOI: 10.3724/SP.J.1142.2014.40383
Abstract：
Salicylic acid (SA), a common plant hormone, can increase the biosynthesis of various compounds, such as taxol in Taxus cells. NPR1 is the key gene in SA mediated plant system acquired resistance (SAR) signal pathway. To clarify the regulating mechanism of SA induced taxol biosynthesis, the TcNPR1 gene was isolated from Taxus cells, and was found to contain a 1857 bp ORF (open reading frame), which may encode a 619 aa protein. Sequence alignment showed TcNPR1 contained typical conserve domains such as Broad-Complex, Tramtrack, and Bric-a-brac/Pox virus and Zinc Finger (BTB/POZ domain), NPR1/NIM1-like-C terminal and ankyrin repeats. Phylogenetic analysis showed that TcNPR1 had a close relationship with AtNPR3 and AtNPR4 of Arabidopsis. Expression analysis revealed that the expression of the TcNPR1 gene was significantly induced by SA, drought and NaCl. In comparison to the wild type, transgenic tobacco plants over-expressing TcNPR1 showed elevated drought tolerance with soluble sugar increasing to 43.8 mg/g(FW) after 4 d of drought treatment, about two times more than the control, revealing that TcNPR1 was a functional protein. The available evidence verified that TcNPR1 may respond to SA and may be involved in systemic acquired resistance (SAR) in Taxus species. Further studies on the TcNPR1 gene are essential for clarifying its function in taxol biosynthesis.
Salicylic acid (SA), a common plant hormone, can increase the biosynthesis of various compounds, such as taxol in Taxus cells. NPR1 is the key gene in SA mediated plant system acquired resistance (SAR) signal pathway. To clarify the regulating mechanism of SA induced taxol biosynthesis, the TcNPR1 gene was isolated from Taxus cells, and was found to contain a 1857 bp ORF (open reading frame), which may encode a 619 aa protein. Sequence alignment showed TcNPR1 contained typical conserve domains such as Broad-Complex, Tramtrack, and Bric-a-brac/Pox virus and Zinc Finger (BTB/POZ domain), NPR1/NIM1-like-C terminal and ankyrin repeats. Phylogenetic analysis showed that TcNPR1 had a close relationship with AtNPR3 and AtNPR4 of Arabidopsis. Expression analysis revealed that the expression of the TcNPR1 gene was significantly induced by SA, drought and NaCl. In comparison to the wild type, transgenic tobacco plants over-expressing TcNPR1 showed elevated drought tolerance with soluble sugar increasing to 43.8 mg/g(FW) after 4 d of drought treatment, about two times more than the control, revealing that TcNPR1 was a functional protein. The available evidence verified that TcNPR1 may respond to SA and may be involved in systemic acquired resistance (SAR) in Taxus species. Further studies on the TcNPR1 gene are essential for clarifying its function in taxol biosynthesis.
2014, 32(4): 394-405.
DOI: 10.3724/SP.J.1142.2014.40394
Abstract：
Hongcaitai (Brassica rapa) is a vegetable that accumulates anthocyanins in both floral stems and leaf petioles. To understand the mechanism underlying the regulation of anthocyanin biosynthesis in B. rapa, anthocyanin accumulation and expression patterns of anthocyanin biosynthesis genes in seedlings of Hongcaitai were investigated. Anthocyanin content in epidermal tissues of petioles were significantly higher than those in leaves with excised mid-veins. Expression levels of all anthocyanin biosynthesis pathway genes were significantly higher in epidermal tissues of petioles than those detected in either endodermal tissues of petioles or in leaves, suggesting that anthocyanin biosynthesis was regulated at the transcriptional level. Transcripts of BrMYBA1 were exclusively expressed in the petiole epidermis; whereas, transcripts of BrbHLH1 and BrWD40 were detected in both leaves and petiole epidermal tissues. This suggests that activation of BrMYBA1 was likely responsible for anthocyanin pigmentation in Hongcaitai. Following cold treatment, seedlings demonstrated increased accumulation of anthocyanins in petiole epidermal tissues, while the transcription of anthocyanin pathway genes was reduced in petiole epidermal tissues.
Hongcaitai (Brassica rapa) is a vegetable that accumulates anthocyanins in both floral stems and leaf petioles. To understand the mechanism underlying the regulation of anthocyanin biosynthesis in B. rapa, anthocyanin accumulation and expression patterns of anthocyanin biosynthesis genes in seedlings of Hongcaitai were investigated. Anthocyanin content in epidermal tissues of petioles were significantly higher than those in leaves with excised mid-veins. Expression levels of all anthocyanin biosynthesis pathway genes were significantly higher in epidermal tissues of petioles than those detected in either endodermal tissues of petioles or in leaves, suggesting that anthocyanin biosynthesis was regulated at the transcriptional level. Transcripts of BrMYBA1 were exclusively expressed in the petiole epidermis; whereas, transcripts of BrbHLH1 and BrWD40 were detected in both leaves and petiole epidermal tissues. This suggests that activation of BrMYBA1 was likely responsible for anthocyanin pigmentation in Hongcaitai. Following cold treatment, seedlings demonstrated increased accumulation of anthocyanins in petiole epidermal tissues, while the transcription of anthocyanin pathway genes was reduced in petiole epidermal tissues.
2014, 32(4): 406-412.
DOI: 10.3724/SP.J.1142.2014.40406
Abstract：
Both lrn1 and prl1, two Brassica napus root mutants insensitive to exogenous cytokinin, show phosphorus efficiency. Compared with‘Ningyou 7’(WT) plants, lrn1 produces more lateral roots and prl1 has longer primary roots under 0.2 μmol/L cytokinins (6-BA) treatment by hydroponics. In this study, differences in root hair, differentiation of epidermal cells and anatomical structure of the root tip of all three genotypes under ddH2O and 0.2 μmol/L 6-BA were studied with stereomicroscopy, non-sliced squash method and paraffin sectioning. Results showed that the root hair number at the zone of maturation in lrn1, prl1 and WT at ddH2O was significantly less than that under 0.2 μmol/L 6-BA treatment. Under 0.2 μmol/L 6-BA treatment, the root hair length and density of WT was the longest and highest, while that of prl1 was the shortest and lowest, and that of lrn1 was between WT and prl1 3 days after germination (DAG3). The zone of cell division and cell elongation of lrn1, prl1 and WT were shortened under 0.2 μmol/L 6-BA DAG6. The meristem areas of lrn1 and prl1 were greater than that of WT, and there were no differences between these two mutants. Moreover, cell structure of the root cap of lrn1 and prl1 were normal, whereas, that of WT was abnormal. Periblem cell arrangements of lrn1 were closer than that of WT and prl1. Under 0.2 μmol/L 6-BA DAG9, lrn1 had four lateral roots, whereas prl1 and WT had no lateral roots. Longer primary root length of prl1 was closely related to its larger meristem area; and more lateral roots in lrn1 under 0.2 μmol/L 6-BA treatment were due to higher cell density in the plerome in the zone of cell division.
Both lrn1 and prl1, two Brassica napus root mutants insensitive to exogenous cytokinin, show phosphorus efficiency. Compared with‘Ningyou 7’(WT) plants, lrn1 produces more lateral roots and prl1 has longer primary roots under 0.2 μmol/L cytokinins (6-BA) treatment by hydroponics. In this study, differences in root hair, differentiation of epidermal cells and anatomical structure of the root tip of all three genotypes under ddH2O and 0.2 μmol/L 6-BA were studied with stereomicroscopy, non-sliced squash method and paraffin sectioning. Results showed that the root hair number at the zone of maturation in lrn1, prl1 and WT at ddH2O was significantly less than that under 0.2 μmol/L 6-BA treatment. Under 0.2 μmol/L 6-BA treatment, the root hair length and density of WT was the longest and highest, while that of prl1 was the shortest and lowest, and that of lrn1 was between WT and prl1 3 days after germination (DAG3). The zone of cell division and cell elongation of lrn1, prl1 and WT were shortened under 0.2 μmol/L 6-BA DAG6. The meristem areas of lrn1 and prl1 were greater than that of WT, and there were no differences between these two mutants. Moreover, cell structure of the root cap of lrn1 and prl1 were normal, whereas, that of WT was abnormal. Periblem cell arrangements of lrn1 were closer than that of WT and prl1. Under 0.2 μmol/L 6-BA DAG9, lrn1 had four lateral roots, whereas prl1 and WT had no lateral roots. Longer primary root length of prl1 was closely related to its larger meristem area; and more lateral roots in lrn1 under 0.2 μmol/L 6-BA treatment were due to higher cell density in the plerome in the zone of cell division.
2014, 32(4): 413-420.
DOI: 10.3724/SP.J.1142.2014.40413
Abstract：
Chinese brake fern (Pteris vittata L.) is the most important and well-known arsenic-hyperaccumulating plant used in phytoremediation of arsenic contaminated soils; however, little is known about its genetic diversity. In this study, 100 clones were randomly selected from the library enriched for AG and AC motifs using a modified FIASCO (Fast Isolation by AFLP of Sequences Containing Repeats) protocol and sequenced. Fifty-one microsatellite loci, of which 60% were pure repeats, were isolated. Twenty-five pairs of primers were designed and synthesized to evaluate their application and polymorphism in 20 individuals per sampling site obtained from Lushan and Enshi, respectively. Primers of eight loci of pure repeats and one locus of intermittent repeats were finally amplified successfully and yielded clear bands. A total of 41 alleles were detected. The allele number per locus of these microsatellites ranged from two to seven (mean 4.56). The expected heterozygosity (Exp-Het) ranged from 0.0494 to 0.8169. No linkage disequilibrium was found. Cross-species amplification demonstrated that six loci were amplified successfully in P. multifida. The markers helped to reveal the genetic variations of arsenic tolerant genotypes and understand the distribution pattern and ecological adaptation mechanism of P. vittata, and also assisted in breeding new varieties of fern for more effective remediation.
Chinese brake fern (Pteris vittata L.) is the most important and well-known arsenic-hyperaccumulating plant used in phytoremediation of arsenic contaminated soils; however, little is known about its genetic diversity. In this study, 100 clones were randomly selected from the library enriched for AG and AC motifs using a modified FIASCO (Fast Isolation by AFLP of Sequences Containing Repeats) protocol and sequenced. Fifty-one microsatellite loci, of which 60% were pure repeats, were isolated. Twenty-five pairs of primers were designed and synthesized to evaluate their application and polymorphism in 20 individuals per sampling site obtained from Lushan and Enshi, respectively. Primers of eight loci of pure repeats and one locus of intermittent repeats were finally amplified successfully and yielded clear bands. A total of 41 alleles were detected. The allele number per locus of these microsatellites ranged from two to seven (mean 4.56). The expected heterozygosity (Exp-Het) ranged from 0.0494 to 0.8169. No linkage disequilibrium was found. Cross-species amplification demonstrated that six loci were amplified successfully in P. multifida. The markers helped to reveal the genetic variations of arsenic tolerant genotypes and understand the distribution pattern and ecological adaptation mechanism of P. vittata, and also assisted in breeding new varieties of fern for more effective remediation.
2014, 32(4): 421-426.
DOI: 10.3724/SP.J.1142.2014.40421
Abstract：
DAPI is a DNA-specific fluorochrome that facilitates observation of nuclei during pollen development and can confirm the developmental stages of pollen grains. However, the nuclei in Hamelia patens Jacq. pollen grains are little stained by DAPI due to the resistance of the pollen wall. An effective "water-bath heating and oxidation" method was used to treat the pollen wall of H. patens. The results showed that the: (1) best incubating conditions for uninucleate microspores and bicellular pollen grains were 20~50 min at 65℃ and 20~40 min at 55℃, respectively; and, (2) lengths of flowers and anthers were 0.90~1.00 cm and 0.50~0.60 cm at the tetrad stage, 1.10~1.60 cm and 0.60~0.85 cm at the uninucleate microspore stage, and 1.80~2.70 cm and 0.91~1.01 cm at the bicellular pollen stage, respectively.
DAPI is a DNA-specific fluorochrome that facilitates observation of nuclei during pollen development and can confirm the developmental stages of pollen grains. However, the nuclei in Hamelia patens Jacq. pollen grains are little stained by DAPI due to the resistance of the pollen wall. An effective "water-bath heating and oxidation" method was used to treat the pollen wall of H. patens. The results showed that the: (1) best incubating conditions for uninucleate microspores and bicellular pollen grains were 20~50 min at 65℃ and 20~40 min at 55℃, respectively; and, (2) lengths of flowers and anthers were 0.90~1.00 cm and 0.50~0.60 cm at the tetrad stage, 1.10~1.60 cm and 0.60~0.85 cm at the uninucleate microspore stage, and 1.80~2.70 cm and 0.91~1.01 cm at the bicellular pollen stage, respectively.
2014, 32(4): 427-433.
DOI: 10.3724/SP.J.1142.2014.40427
Abstract：
In order to increase Pinus pumila seed viability, five treatments, namely, water soak, NaOH solution soak, PEG6000 (PEG, polyethylene glycol) solution soak, low-temperature, absorption of water and desiccation treatments, were used to explore factors that affect the viability of Pinus pumila seeds. Groups of each factor were tested under different concentrations, durations and temperatures, with indigo dyeing applied to measure seed viabilities. Results showed that the PEG6000 solution soak at 10% concentration, initial temperature of 60℃, and 36 h of soaking showed the most improved seed viability. Water soaking also enhanced the viability of the Pinus pumila seeds, as well as cryogenics and absorption of water and desiccation treatments. NaOH solution with concentrations of 4%-12% lowered seed viability. Testing revealed that the PEG6000 treatment was the most effective method for improving the viability of Pinus pumila, which can be applied to the cultivation and better utilization of Pinus pumila.
In order to increase Pinus pumila seed viability, five treatments, namely, water soak, NaOH solution soak, PEG6000 (PEG, polyethylene glycol) solution soak, low-temperature, absorption of water and desiccation treatments, were used to explore factors that affect the viability of Pinus pumila seeds. Groups of each factor were tested under different concentrations, durations and temperatures, with indigo dyeing applied to measure seed viabilities. Results showed that the PEG6000 solution soak at 10% concentration, initial temperature of 60℃, and 36 h of soaking showed the most improved seed viability. Water soaking also enhanced the viability of the Pinus pumila seeds, as well as cryogenics and absorption of water and desiccation treatments. NaOH solution with concentrations of 4%-12% lowered seed viability. Testing revealed that the PEG6000 treatment was the most effective method for improving the viability of Pinus pumila, which can be applied to the cultivation and better utilization of Pinus pumila.
