Arabinogalactan proteins(AGPs)are widely distributed in the plant kingdom and play a vital role during the process of plant sexual reproduction.In this study,we performed a comprehensive identification of the PbrAGPs ...Arabinogalactan proteins(AGPs)are widely distributed in the plant kingdom and play a vital role during the process of plant sexual reproduction.In this study,we performed a comprehensive identification of the PbrAGPs expressed in pear pollen and further explored their influences on pollen tube growth.Among the 187 PbrAGPs that were found to be expressed in pear pollen tubes,38 PbrAGPs were specifically expressed in pollen according to the RNA-seq data.The PbrAGPs were divided into two groups of highly expressed and specifically expressed in pear pollen.We further tested their expression patterns using RT-PCR and RT-qPCR.Most of the PbrAGPs were expressed in multiple tissues and their expression levels were consistent with reads per kilobase per million map reads(RPKM)values during pollen tube growth,implying that PbrAGPs might be involved in the regulation of pear pollen tube growth.We also constructed phylogenetic trees to identify the functional genes in pear pollen tube growth.Therefore,19 PbrAGPs(PbrAGP1 to PbrAGP19)were selected to test their influences on pollen tube growth.Recombinant proteins of the 19 PbrAGP-His were purified and used to treat pear pollen,and 11 of the PbrAGP-His recombinant proteins could promote pear pollen tube growth.Additionally,pollen tube growth was inhibited when the expression levels of PbrAGP1 and PbrAGP5 were knocked down using an antisense oligonucleotide assay.PbrAGP1 and PbrAGP5 were localized in the plasma membrane and might not alter the distribution of pectin in the pollen tube.In summary,this study identified the PbrAGPs expressed in pear pollen and lays the foundation for further exploring their functions in pollen tube growth.展开更多
The pollen tube pathway method of transformation has been reported to be successful in most crops, but less successfu in maizc. DNA can be transferred by cutting the stigma following pollination and applying the DNA s...The pollen tube pathway method of transformation has been reported to be successful in most crops, but less successfu in maizc. DNA can be transferred by cutting the stigma following pollination and applying the DNA solution in a suitable period DNA presumably reaches the ovary by flowing down the pollen tube and then integrates into the just fertilized but undivided zygotic cells. To provide the molecular evidence for this procedure, the plasmids pGBIRC carrying a CaMV35S promoter-PPT acetyle transferase (bar) gene-nos terminator genc fusion construct were used. Total 3 276 seeds were produced from the ears trcated with DNA. It was found that 35 scedlings were GUS assay positive, but less intense than that of the positive controls, of which 17 were PCR amplification positive. But, only 13 of the seeds from the plants treated with DNA containing the bar gene were found to be resistant compared with the negative control. Less than 1.07% of progeny seedlings tested cxpressed a herbicide positive reaction and polymerase chain reaction (PCR) with seedling DNA did detect the bar genc. Morphological variation was observed in six plants. We succeed in obtain PPT-resistant maize inbred lines via pollen tube pathway展开更多
The germination of pollen grain in vitro and the growth of pollen tube in the pistil of rice were observed with a microscope. The stigma was removed at different time points after pollination to study its effect on se...The germination of pollen grain in vitro and the growth of pollen tube in the pistil of rice were observed with a microscope. The stigma was removed at different time points after pollination to study its effect on seed setting rate. The rice pollen grain started to germinate at 2 min after pollination and the pollen tube penetrated stigma into style in 5-10 min, 30 min later the end of pollen tube reached the bottom of ovary, and only some pollen tubes arrived at embryo sac at 40 min after pollination. Meanwhile, a small amount of callose began to deposit in the pollen tubes, a great deal of callose was observed at 50 min after pollination, whereas the pollen grain began to shrink. The growing rates of pollen tube in the rice stigma, style and ovary were 1500, 5000, and 5400 μm/h, respectively. The seed setting rate was quite low when the stigma was removed at about 10-15 min after pollination, gradually increased when it removed at 20 min to 50 min after pollination, and over 60% when it removed at 50 min after pollination and finally tended to be stable.展开更多
Low-energy ion implantation, as a new technology to produce mutation in plant breeding, has been widely applied in agriculture in China. But so far there is a little understanding of the underlying mechanisms responsi...Low-energy ion implantation, as a new technology to produce mutation in plant breeding, has been widely applied in agriculture in China. But so far there is a little understanding of the underlying mechanisms responsible for its biological effects at the cellular level. Here we report the biological effects of a nitrogen ion beams of 30 keV on the pollen grains of Pinus thunbergii Parl. In general, ion implantation inhibited pollen germination. The dose-response curve presented a particular saddle-like pattern. Ion implantation also changed the dimension of the elongated tubes and significantly induced tip swelling. Confocal microscopy indicated that the pollen tube tips in P. thunbergii contained an enriched network of microtubules. Ion implantation led to the disruption of microtubules especially in swollen tips. Treatment with colchicine demonstrated that tip swelling was caused by the disruption of microtubules in the tip, indicating a unique role for microtubules in maintaining the tip integrality of the pollen tube in conifer. Our results suggest that ion implantation induce the disruption of microtubule organization in pollen and pollen tubes and subsequently cause morphological abnormalities in the pollen tubes. This study may provide a clue for further investigation on the interaction between low-energy ion beams and pollen tube growth.展开更多
Pollen grains of Pinus thunbergii Parl. (Japanese black pine) were implanted with 30 keV nitrogen ion beams and the effects of nitrogen ion implantation on pollen tube growth in vitro and the organization of actin c...Pollen grains of Pinus thunbergii Parl. (Japanese black pine) were implanted with 30 keV nitrogen ion beams and the effects of nitrogen ion implantation on pollen tube growth in vitro and the organization of actin cytoskeleton in the pollen tube cell were investigated using a confocal laser scanning microscope after fluorescence labeling. Treatment with ion implantation significantly blocked pollen tube growth. Confocal microscopy showed that ion implantation disrupted actin filament cytoskeleton organization in the pollen tube. It was found that there was a distinct correlation between the inhibition of pollen tube growth and the disruption of actin cytoskeleton organization, indicating that an intact actin cytoskeleton is essential for continuous pollen tube elongation in Pinus thunbergii. Although the detailed mechanism for the ion-implantation-induced bioeffect still remains to be elucidated, the present study assumes that the cytoskeleton system in pollen grains may provide a key target in response to ion beam implantation and is involved in mediating certain subsequent cytological changes.展开更多
Kanamycin was used to screen To seeds of the variety Dongnong 46 transformed by means of pollen-tube method. The results showed that 400 mg·L^-1 kanamycin could inhibit growth of non-transgenic plants, and 2 posi...Kanamycin was used to screen To seeds of the variety Dongnong 46 transformed by means of pollen-tube method. The results showed that 400 mg·L^-1 kanamycin could inhibit growth of non-transgenic plants, and 2 positive plants were gotten combined with Gus dyeing and PCR detection. It is proved that this method is economic and effective in preliminary screening the transgenic plants.展开更多
In this article, the functions of D-myo-inositol-1,4,5-trisphosphate (Ins [1,4,5] P3) in regulating pollen tube polar growth were investigated by application of caged version of the phosphoinositides. To increase the ...In this article, the functions of D-myo-inositol-1,4,5-trisphosphate (Ins [1,4,5] P3) in regulating pollen tube polar growth were investigated by application of caged version of the phosphoinositides. To increase the intracellular Ins(1,4,5)P3 concentration at the apical region of pollen tube, the caged Ins(1,4,5)P3 loaded by osmotic shock was activated by 10 s 360 nm UV flash at this domain (10 μm from the tip). More than 70% pollen tubes were induced swelling at apex and/or growth axis reorientation, accompanying temporarily growth arrest, by localized increase of Ins(1,4,5)P3 concentration (n=21). While, pollen tubes without being loaded with caged Ins(1,4,5)P3 had not response to the same dosage UV flash. With FM 1-43 fluorescent staining, it was found that growth perturbation by UV activated caged Ins(1,4,5)P3 had tight link with membrane trafficking at the apical zone of pollen tubes. Upon UV pulse, the apical V-shaped bright area where was full of secretory vesicles spread to a much broader region, which implied that actin filaments at the apical region were remodeled. It was also observed that the FM 1-43 fluorescence intensity at tip remarkably increased than that before UV flash, which demonstrated that more secretory vesicles were accumulated at this region. To estimate the role of Ins(1,4,5)P3 in modulating intracellular calcium concentration and distribution, dextran conjugated fluorescent dye Calcium Green-1 and Rhodamine B were microinjected into pollen tubes together with caged Ins(1,4,5)P3. The results showed that calcium concentration at the subapical region increased upon UV released Ins(1,4,5)P3. Consequently, the tip-focused calcium gradient under the apical dome of pollen tube was disturbed. Simultaneously, the pollen tube bulged at the apical region and its growth rate decreased. As the tip-focused calcium gradient was reestablished, the pollen tube morphology and growth recovered to the normal level. Therefore, Ins(1,4,5)P3 can modulate pollen tube growth rate and direction through mobilizing intracellular calcium and regulating vesicle trafficking during pollen tube finding its way to the ovary.展开更多
Tube hydroforming process is a relative new process f or production of structural parts of low weight and high rigidity. The successfu lness of the process depends largely on the a proper selection of loading path w h...Tube hydroforming process is a relative new process f or production of structural parts of low weight and high rigidity. The successfu lness of the process depends largely on the a proper selection of loading path w hich is axial feeding distance as related to the applied internal pressure. Due to the complicated nature of plastic deformation, a optimum loading path which w ill guarantee good hydroformed parts free of winkle and fracture has often to be determined by finite element analysis. In order to save trials and errors, adap tive FEM simulation method has been developed. To effectively apply the adaptive simulation method, we have to know the applicability of the method. In this pap er, a classification of tube hydroforming (THF) processes based on sensitivity to loading parameters has been suggested. Characteristics of the classification have been analyzed in terms of failure mode, dominant loading parameters and th eir working windows. It was discussed that the so called pressure dominant THF p rocess is the most difficult process for both simulation in FEM analysis and pra ctical operation in real manufacturing situation. To effectively find out the op timum loading path for pressure dominant THF process, adaptive FEM simulation st rategies are mostly needed.展开更多
The success of sexual plant reproduction is directly influenced by specific interactions between the pollen and pistil.Light,fluorescence and scanning electron microscopy techniques were used to evaluate the steps of ...The success of sexual plant reproduction is directly influenced by specific interactions between the pollen and pistil.Light,fluorescence and scanning electron microscopy techniques were used to evaluate the steps of pollination in sour passion fruit plants(Passiflora edulis Sims).In the compatible interaction,pollen tubes grow through stigma projections towards the ovary.The pollen grain surface was found to be spheroidal and to consist of heteroreticulate exine with six colpi.Furthermore,analysis in vivo of pollenpistil interactions indicated that stigmas of flowers 24 hours before anthesis are unable to discriminate compatible(genetically unrelated)and incompatible(genetically related)pollen grains.Taken together,these results provide insight into the cellular mechanisms underlying pollination in passion fruit plants.展开更多
This study aimed to observe the viability of the pollen grains of Malpighia emarginata DC. (West Indian cherry) and the action of a lectin in their germination. Lectins are proteins that specifically interact with car...This study aimed to observe the viability of the pollen grains of Malpighia emarginata DC. (West Indian cherry) and the action of a lectin in their germination. Lectins are proteins that specifically interact with carbohydrates, but don’t modify them and bind with high affinity and specificity, promoting a transfer of information that is clearly central to many cellular processes in living beings. For the viability test was used aniline blue in lactophenol. The in vitro germination test used was the hanging drop method, in control medium containing sucrose, boric acid, calcium nitrate and agar. The experiment dealt with three different treatments in order to pollen germination: growing medium without addition of lectin, with 1.0 μg/ml and with 3.0 μg/ml CPL lectin. This lectin is extracted from seeds of Crotalaria pallida L.-Leguminosae. Data on pollen grains were analyzed by one-way ANOVA, with 95% reliability and comparison of averages by Turkey test at 5% probability. It was found that despite previous high viability of the pollen grains (c. 70%), a germinability rate has been low, yet exceptionally larger in pollen samples placed on a growing medium with addition of 3.0 μg/ml of CPL lectin (24%). There was no significant difference among the pollen grains germinate in medium without lectin and those in medium with the addition of only 1.0 μg/ml. According to data obtained in the treatments, CPL lectin, with concentration of 3.0 μg/ml, influenced the formation of the pollen tube and thus more pollen germinated in Malpighia emarginata.展开更多
基金supported by the earmarked fund for China Agriculture Research System(CARS-28-37)the Agricultural Science and Technology Innovation Project of Shandong Academy of Agricultural Sciences,China(CXGC2022E21)+1 种基金the Youth Foundation of Shandong Institute of Pomology,China(GSS2022QN11)the Natural Science Foundation of Shandong Province,China(ZR2019BC075,ZR2020MC141,and ZR2021MC177)。
文摘Arabinogalactan proteins(AGPs)are widely distributed in the plant kingdom and play a vital role during the process of plant sexual reproduction.In this study,we performed a comprehensive identification of the PbrAGPs expressed in pear pollen and further explored their influences on pollen tube growth.Among the 187 PbrAGPs that were found to be expressed in pear pollen tubes,38 PbrAGPs were specifically expressed in pollen according to the RNA-seq data.The PbrAGPs were divided into two groups of highly expressed and specifically expressed in pear pollen.We further tested their expression patterns using RT-PCR and RT-qPCR.Most of the PbrAGPs were expressed in multiple tissues and their expression levels were consistent with reads per kilobase per million map reads(RPKM)values during pollen tube growth,implying that PbrAGPs might be involved in the regulation of pear pollen tube growth.We also constructed phylogenetic trees to identify the functional genes in pear pollen tube growth.Therefore,19 PbrAGPs(PbrAGP1 to PbrAGP19)were selected to test their influences on pollen tube growth.Recombinant proteins of the 19 PbrAGP-His were purified and used to treat pear pollen,and 11 of the PbrAGP-His recombinant proteins could promote pear pollen tube growth.Additionally,pollen tube growth was inhibited when the expression levels of PbrAGP1 and PbrAGP5 were knocked down using an antisense oligonucleotide assay.PbrAGP1 and PbrAGP5 were localized in the plasma membrane and might not alter the distribution of pectin in the pollen tube.In summary,this study identified the PbrAGPs expressed in pear pollen and lays the foundation for further exploring their functions in pollen tube growth.
文摘The pollen tube pathway method of transformation has been reported to be successful in most crops, but less successfu in maizc. DNA can be transferred by cutting the stigma following pollination and applying the DNA solution in a suitable period DNA presumably reaches the ovary by flowing down the pollen tube and then integrates into the just fertilized but undivided zygotic cells. To provide the molecular evidence for this procedure, the plasmids pGBIRC carrying a CaMV35S promoter-PPT acetyle transferase (bar) gene-nos terminator genc fusion construct were used. Total 3 276 seeds were produced from the ears trcated with DNA. It was found that 35 scedlings were GUS assay positive, but less intense than that of the positive controls, of which 17 were PCR amplification positive. But, only 13 of the seeds from the plants treated with DNA containing the bar gene were found to be resistant compared with the negative control. Less than 1.07% of progeny seedlings tested cxpressed a herbicide positive reaction and polymerase chain reaction (PCR) with seedling DNA did detect the bar genc. Morphological variation was observed in six plants. We succeed in obtain PPT-resistant maize inbred lines via pollen tube pathway
基金the National Natural Science Foundation of China (Grants Nos. 30070454 and 30471045)
文摘The germination of pollen grain in vitro and the growth of pollen tube in the pistil of rice were observed with a microscope. The stigma was removed at different time points after pollination to study its effect on seed setting rate. The rice pollen grain started to germinate at 2 min after pollination and the pollen tube penetrated stigma into style in 5-10 min, 30 min later the end of pollen tube reached the bottom of ovary, and only some pollen tubes arrived at embryo sac at 40 min after pollination. Meanwhile, a small amount of callose began to deposit in the pollen tubes, a great deal of callose was observed at 50 min after pollination, whereas the pollen grain began to shrink. The growing rates of pollen tube in the rice stigma, style and ovary were 1500, 5000, and 5400 μm/h, respectively. The seed setting rate was quite low when the stigma was removed at about 10-15 min after pollination, gradually increased when it removed at 20 min to 50 min after pollination, and over 60% when it removed at 50 min after pollination and finally tended to be stable.
基金supported by National Key Project of China (No. 2001BA302B)
文摘Low-energy ion implantation, as a new technology to produce mutation in plant breeding, has been widely applied in agriculture in China. But so far there is a little understanding of the underlying mechanisms responsible for its biological effects at the cellular level. Here we report the biological effects of a nitrogen ion beams of 30 keV on the pollen grains of Pinus thunbergii Parl. In general, ion implantation inhibited pollen germination. The dose-response curve presented a particular saddle-like pattern. Ion implantation also changed the dimension of the elongated tubes and significantly induced tip swelling. Confocal microscopy indicated that the pollen tube tips in P. thunbergii contained an enriched network of microtubules. Ion implantation led to the disruption of microtubules especially in swollen tips. Treatment with colchicine demonstrated that tip swelling was caused by the disruption of microtubules in the tip, indicating a unique role for microtubules in maintaining the tip integrality of the pollen tube in conifer. Our results suggest that ion implantation induce the disruption of microtubule organization in pollen and pollen tubes and subsequently cause morphological abnormalities in the pollen tubes. This study may provide a clue for further investigation on the interaction between low-energy ion beams and pollen tube growth.
基金National Science Foundation of Fujian Province of China(No.B0610031)Science and Technology Program of Put-Jan Municipality of China(No.2006N17)
文摘Pollen grains of Pinus thunbergii Parl. (Japanese black pine) were implanted with 30 keV nitrogen ion beams and the effects of nitrogen ion implantation on pollen tube growth in vitro and the organization of actin cytoskeleton in the pollen tube cell were investigated using a confocal laser scanning microscope after fluorescence labeling. Treatment with ion implantation significantly blocked pollen tube growth. Confocal microscopy showed that ion implantation disrupted actin filament cytoskeleton organization in the pollen tube. It was found that there was a distinct correlation between the inhibition of pollen tube growth and the disruption of actin cytoskeleton organization, indicating that an intact actin cytoskeleton is essential for continuous pollen tube elongation in Pinus thunbergii. Although the detailed mechanism for the ion-implantation-induced bioeffect still remains to be elucidated, the present study assumes that the cytoskeleton system in pollen grains may provide a key target in response to ion beam implantation and is involved in mediating certain subsequent cytological changes.
文摘Kanamycin was used to screen To seeds of the variety Dongnong 46 transformed by means of pollen-tube method. The results showed that 400 mg·L^-1 kanamycin could inhibit growth of non-transgenic plants, and 2 positive plants were gotten combined with Gus dyeing and PCR detection. It is proved that this method is economic and effective in preliminary screening the transgenic plants.
文摘In this article, the functions of D-myo-inositol-1,4,5-trisphosphate (Ins [1,4,5] P3) in regulating pollen tube polar growth were investigated by application of caged version of the phosphoinositides. To increase the intracellular Ins(1,4,5)P3 concentration at the apical region of pollen tube, the caged Ins(1,4,5)P3 loaded by osmotic shock was activated by 10 s 360 nm UV flash at this domain (10 μm from the tip). More than 70% pollen tubes were induced swelling at apex and/or growth axis reorientation, accompanying temporarily growth arrest, by localized increase of Ins(1,4,5)P3 concentration (n=21). While, pollen tubes without being loaded with caged Ins(1,4,5)P3 had not response to the same dosage UV flash. With FM 1-43 fluorescent staining, it was found that growth perturbation by UV activated caged Ins(1,4,5)P3 had tight link with membrane trafficking at the apical zone of pollen tubes. Upon UV pulse, the apical V-shaped bright area where was full of secretory vesicles spread to a much broader region, which implied that actin filaments at the apical region were remodeled. It was also observed that the FM 1-43 fluorescence intensity at tip remarkably increased than that before UV flash, which demonstrated that more secretory vesicles were accumulated at this region. To estimate the role of Ins(1,4,5)P3 in modulating intracellular calcium concentration and distribution, dextran conjugated fluorescent dye Calcium Green-1 and Rhodamine B were microinjected into pollen tubes together with caged Ins(1,4,5)P3. The results showed that calcium concentration at the subapical region increased upon UV released Ins(1,4,5)P3. Consequently, the tip-focused calcium gradient under the apical dome of pollen tube was disturbed. Simultaneously, the pollen tube bulged at the apical region and its growth rate decreased. As the tip-focused calcium gradient was reestablished, the pollen tube morphology and growth recovered to the normal level. Therefore, Ins(1,4,5)P3 can modulate pollen tube growth rate and direction through mobilizing intracellular calcium and regulating vesicle trafficking during pollen tube finding its way to the ovary.
文摘Tube hydroforming process is a relative new process f or production of structural parts of low weight and high rigidity. The successfu lness of the process depends largely on the a proper selection of loading path w hich is axial feeding distance as related to the applied internal pressure. Due to the complicated nature of plastic deformation, a optimum loading path which w ill guarantee good hydroformed parts free of winkle and fracture has often to be determined by finite element analysis. In order to save trials and errors, adap tive FEM simulation method has been developed. To effectively apply the adaptive simulation method, we have to know the applicability of the method. In this pap er, a classification of tube hydroforming (THF) processes based on sensitivity to loading parameters has been suggested. Characteristics of the classification have been analyzed in terms of failure mode, dominant loading parameters and th eir working windows. It was discussed that the so called pressure dominant THF p rocess is the most difficult process for both simulation in FEM analysis and pra ctical operation in real manufacturing situation. To effectively find out the op timum loading path for pressure dominant THF process, adaptive FEM simulation st rategies are mostly needed.
基金supported by the FAPERJ,CAPES and CNPq of Brazil.
文摘The success of sexual plant reproduction is directly influenced by specific interactions between the pollen and pistil.Light,fluorescence and scanning electron microscopy techniques were used to evaluate the steps of pollination in sour passion fruit plants(Passiflora edulis Sims).In the compatible interaction,pollen tubes grow through stigma projections towards the ovary.The pollen grain surface was found to be spheroidal and to consist of heteroreticulate exine with six colpi.Furthermore,analysis in vivo of pollenpistil interactions indicated that stigmas of flowers 24 hours before anthesis are unable to discriminate compatible(genetically unrelated)and incompatible(genetically related)pollen grains.Taken together,these results provide insight into the cellular mechanisms underlying pollination in passion fruit plants.
文摘This study aimed to observe the viability of the pollen grains of Malpighia emarginata DC. (West Indian cherry) and the action of a lectin in their germination. Lectins are proteins that specifically interact with carbohydrates, but don’t modify them and bind with high affinity and specificity, promoting a transfer of information that is clearly central to many cellular processes in living beings. For the viability test was used aniline blue in lactophenol. The in vitro germination test used was the hanging drop method, in control medium containing sucrose, boric acid, calcium nitrate and agar. The experiment dealt with three different treatments in order to pollen germination: growing medium without addition of lectin, with 1.0 μg/ml and with 3.0 μg/ml CPL lectin. This lectin is extracted from seeds of Crotalaria pallida L.-Leguminosae. Data on pollen grains were analyzed by one-way ANOVA, with 95% reliability and comparison of averages by Turkey test at 5% probability. It was found that despite previous high viability of the pollen grains (c. 70%), a germinability rate has been low, yet exceptionally larger in pollen samples placed on a growing medium with addition of 3.0 μg/ml of CPL lectin (24%). There was no significant difference among the pollen grains germinate in medium without lectin and those in medium with the addition of only 1.0 μg/ml. According to data obtained in the treatments, CPL lectin, with concentration of 3.0 μg/ml, influenced the formation of the pollen tube and thus more pollen germinated in Malpighia emarginata.