The microscopic investigation of the floral development of sweet cherry(Prunus avium L. cv. Hongdeng) from a warm winter climate(Shanghai) and cold winter climate(Tai'an, Shandong Province, China) was conducted to...The microscopic investigation of the floral development of sweet cherry(Prunus avium L. cv. Hongdeng) from a warm winter climate(Shanghai) and cold winter climate(Tai'an, Shandong Province, China) was conducted to explore the reason of low fruit set. The effect of hydrogen cyanamide(HCN) on floral development under warm winter conditions was also investigated. Trees grown in Shanghai with insufficient chilling accumulation exhibited little difference in the progression of microspore development compared to trees in Tai'an that accumulated adequate chilling, but showed substantial delays in ovule and embryo sac development. The growth of nucelli did not proceed beyond the macrospore mother cell and macrospore stages with abortion rates of 13, 15 and 45% by 6, 3 and 0 d before full bloom, respectively. These abnormalities in the ovule and embryo sac in the Shanghai-grown trees were eliminated by HCN application. These results suggest that chilling regulates the development of female floral organs in winter dormancy; therefore, insufficient chilling accumulation, causing abnormality of the female floral organs, restricts the cultivation of sweet cherry in warm winter regions. Interestingly, HCN application, which decreased the chilling requirements for Hongdeng, may be a potential strategy for sweet cherry cultivation in warm winter regions.展开更多
[Objectives]This study was conducted to explore the mechanism of soybean cytoplasmic-nuclear male sterility.[Methods]With soybean cytoplasmic-nuclear male sterile line JLCMS9 A and its homotype maintainer line JLCMS9 ...[Objectives]This study was conducted to explore the mechanism of soybean cytoplasmic-nuclear male sterility.[Methods]With soybean cytoplasmic-nuclear male sterile line JLCMS9 A and its homotype maintainer line JLCMS9 B as experimental materials,the activity of superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT),malondialdehyde(MDA)content,starch content,soluble protein content,soluble sugar content and free proline content in flower buds,alabastrums and mature flowers were determined,and the contents and changes of auxin(IAA),gibberellin(GA3),isopentenyl adenosine(iPA)and abscisic acid(ABA)at the three stages were analyzed.[Results]The activity of SOD and CAT and the contents of MDA and free proline in the sterile line at the flower bud stage were lower than those of the maintainer line,but the opposite was true at the alabastrum stage and the flowering stage,and their values were higher than those of the maintainer line;the POD activity of the sterile line was significantly lower than that of the maintainer line at the flower bud stage,and the opposite was true at the alabastrum stage and the flowering stage,and its values were higher than those of the maintainer line;and the starch content and soluble sugar content of sterile line 9 A showed an overall upward trend,and were significantly lower than those of the maintainer line 9 B at the alabastrum stage and the flowering stage.During the whole development process of floral organs,the content of IAA in sterile line 9 A showed a trend of first increasing and then decreasing,and the content of iPA increased gradually.The contents of hormones in the sterile line were lower than those in the maintainer line.The ratios of IAA/ABA,IAA/GA3,IAA/iPA and ABA/GA3 in the sterile line were significantly different from those in the maintainer line.It is inferred that the abnormal physiological characteristics of floral organ development are related to the cytoplasmic-nuclear male sterility of soybean.The alabastrum stage may be a critical period for the occurrence of abnormal physiological and biochemical indexes in the floral organs of soybean cytoplasmic-nuclear male sterile lines.[Conclusions]This study provides a theoretical basis for the breeding of fine sterile lines of soybean and the research on the mechanism of sterility.展开更多
Under the environment of an artificial climate chamber,supercooling point (SCP) and freezing point (FP) in flower and young fruit at different development stages and freezing injuries of floral organs were studied. Th...Under the environment of an artificial climate chamber,supercooling point (SCP) and freezing point (FP) in flower and young fruit at different development stages and freezing injuries of floral organs were studied. The apricot cultivars tested were Kety,Golden Sun and Honghebao. With the development of flower buds,SCP and FP increased,which indicated that their cold resistance decreased. SCP and FP varied with different floral organs. For different apricot cultivars,it was found that,the lower SCP or FP in floral organs was,the more resistant capacity the cultivar had,and the larger the temperature interval from SCP to FP was. SCP was not a constant value,but a range. Frequency distribution of SCP in petals was more dispersing than that in stamens and pistils. Floral organs could maintain a supercooling state to avoid ice formation,but they were sensitive to freezing. Once floral organs froze,they turned brown after thawing.展开更多
This study was conducted to investigate the dynamic changes of several hormones in Rhododendron simsii floral organs to provide theoretical basis for controlling its flowering period.A R.simsii variety " Purple C...This study was conducted to investigate the dynamic changes of several hormones in Rhododendron simsii floral organs to provide theoretical basis for controlling its flowering period.A R.simsii variety " Purple Crane" was selected as the experimental material,and its flower organs were sampled at nine floral developmental stages to measure the contents of gibberellic acid-3( GA_3),abscisic acid( ABA),indole-3-acetic acid( IAA),and zeatin riboside( ZR) through enzyme-linked immunosorbent assay( ELISA).The results showed that the content of ZR was highest at full flowering stage; IAA and GA_3 contents were higher than other stages in the process of flower bud differentiation and flowering.ABA played an important role in the regulation of flower bud formation.The results will provide theoretical references for exploring the regulation of plant hormones towards Rhododendron flower traits and breeding new varieties.展开更多
Allelic diversity for five genetic loci (DL, FON4, OsMADS24, OsMADS45 and Spw1) associated with floral organ development were investigated among a small heterogeneous rice population which included one wild species (O...Allelic diversity for five genetic loci (DL, FON4, OsMADS24, OsMADS45 and Spw1) associated with floral organ development were investigated among a small heterogeneous rice population which included one wild species (O. rufipogon Griffiths), one indigenous less popular natural floral organ mutant (O. sativa var. indica cv. Jugal), one indigenous normal line (O. sativa var. indica cv. Bhutmoori) and one improved high yielding line (O. sativa var. indica cv. IR 36). Detailed spikelet morphology showed that var. Jugal had variable number (1 - 3) of carpels within a single spikelet which was unique and resulted in variable (1 - 3) number of kernels within a single matured spikelet (grain). The genomic DNA of each investigated line was amplified with primer sequences designed from the selected genetic loci and the derived polymorphism profiles were used for study of allelic diversity for the studied loci. The derived genetic distances among the rice lines were used for dendrogram construction. In constructed dendrogram, the mutant genotype (Jugal) showed highest similarity with the wild rice (O. rufipogon) instead of the rice lines. To verify this finding, the genomic DNA of each studied line was also amplified with four SSR loci, tightly linked to saltol QTL, mapped to rice chromosome 1. The amplified products were screened for polymorphism and another dendrogram was constructed to reveal the genetic distance among the lines for selected salt tolerance linked SSR loci. In SSR derived dendrogram, the wild rice (O. rufipogon) got totally separated from the all three rice genotypes though all the studied four lines showed equal sensitivity for salt sensitivity in a physiological screening experiment. From the combined experiment, it can be concluded that genetic architecture of floral organ development loci in var. Jugal may have some uniqueness which is not present in normal rice but common to O. rufipogon, a species which is regarded as immediate progenitor of present day modern rice (O. sativa). Though this uniqueness was not confirmed by second set genetic loci associated with salt tolerance in rice, the information resulted from this experiment was preliminary and based only on allelic size (molecular weight of amplicon), which should be confirmed through sequence analysis for further analysis.展开更多
A rice floral organ mutant, srs2, derived from a spontaneous mutation, was first discovered in a japonica rice variety GNZ. The mutant displayed various abnormalities in floral organ including longer paleas/lemmas, sp...A rice floral organ mutant, srs2, derived from a spontaneous mutation, was first discovered in a japonica rice variety GNZ. The mutant displayed various abnormalities in floral organ including longer paleas/lemmas, split spikelets, palea/lemma-like lodicules, two florets of the same rachilla, a decrease in stamen number, and an increase in pistil number. Moreover, the seed-setting rate of the mutant was also reduced to 9.8%. Observations of the floral organ morphogenesis by a scanning electron microscope (SEM) in the mutant indicated that the development of androecium and gynoecia was abnormal and an additional floret and several palea/lemma-like lodicules were usually formed by the irregular development of the floral meristem. Genetic analysis of 4 F2 and 2 BC1F1 populations showed that the mutation was controlled by a single recessive gene, and designated as srs2 (spit rice spikelet 2). Screening of 643 F2 mutant individuals derived from the cross of srs2 × 202R with simple sequence repeat (SSR) markers demonstrated that SRS2 is located between the molecular marker S31 and L75, at a distances of 0.07 and 2 cM, respectively, on chromosome 3. The SRS2 gene was also discussed to be a new floral organ identity gene in rice.展开更多
[Objective]This study aimed to investigate various factors affecting the dedifferentiation of different floral organs of Jinxiu wild chive.[Method]Floral organs of Jinxiu wild chive were cultured in vitro,to analyze t...[Objective]This study aimed to investigate various factors affecting the dedifferentiation of different floral organs of Jinxiu wild chive.[Method]Floral organs of Jinxiu wild chive were cultured in vitro,to analyze the effects of basic medium,exogenous hormone type and combination,and blossoming status of buds on callus induction.[Result]MS medium was the most suitable medium for callus induction from buds.NAA was conducive to improving callus formation rate compared with other auxins.Non-blossomed buds exhibited the highest rate of callus induction.Under the same culture conditions,the rate of callus induction varied extremely significantly among various floral organs;to be specific,the rate of callus induction from floral disc reached the highest,followed successively by bud and pedicel,but no callus was formed in floral axis group.[Conclusion]This study laid the foundation for further establishment of tissue culture and rapid propagation system of Jinxiu wild chive and other wild chives and provided technical support for the preservation,development and utilization of wild chive germplasm resources.展开更多
A spontaneous rice mutant named floral organ number 3 (fon3) had major mutations in floral organ numbers. Genetic analysis indicated thatfon3 acted as a single recessive gene. Microscopic observation showed that the n...A spontaneous rice mutant named floral organ number 3 (fon3) had major mutations in floral organ numbers. Genetic analysis indicated thatfon3 acted as a single recessive gene. Microscopic observation showed that the number of floral organs infon3 increased centripetally. For example, the number of pistils was the more frequently increased than organs in the outer whorls. Homeotic conversion of lodicules and glumes into palea/lemma-like organs was observed in some flowers. Scanning electron microscopy observation showed that the size of flower meristems was maintained the same or similar until the lemma primordium started to differentiate, at which time the floral meristem became enlarged, suggesting abnormal development of the inner whorls of rice florets. The relationship offon3 with other similar rice mutants is discussed.展开更多
Current understanding of the classical ABC model of floral development has provided a new set of characters to evaluate floral evolution. However, what is still lacking is a clear assessment of this genetic program ac...Current understanding of the classical ABC model of floral development has provided a new set of characters to evaluate floral evolution. However, what is still lacking is a clear assessment of this genetic program across monocots. Here, to investigate the evolution of members of class A and B genes in monocots, we report the sequence characteristic and transcript expression of three new MADS-box genes in Alpinia oblongifolia Hayata. Sequence and phylogenetic analysis reveals that these genes are FUL-like and AP3-like. Therefore, they were termed AoFL1, AoFL2 and AoAP3. AoFL1 contains the FUL motif, but AoFL2 lacks this motif. Their expression revealed by in situ hybridization may reflect the ancestral function of FUL-like genes in the specification of inflorescence and floral meristems. The AoAP3 gene contains two conserved motifs, the PI-derived and paleoAP3 motifs. The AoAP3 transcripts located to the corolla and stamen, and hybridization signals were detected in the central whorl. These expression patterns suggest that the functions of homologous organ identity genes are diversified in A. oblongifolia. The implications of these findings on the conservation of homologous gene function are discussed.展开更多
Polyploidization is the evolution trend of many crops, and the yield increased obviously after polyploidization. The polyploidization of rice often brings "gigas" of both vegetative organs and seeds. However...Polyploidization is the evolution trend of many crops, and the yield increased obviously after polyploidization. The polyploidization of rice often brings "gigas" of both vegetative organs and seeds. Howevere, in rice breeding, it is required for restoring lines to have not only big anthers but also abundant pollens. People often doubt that the enlargement of the floral organ may just be enlargement of cell size in polyploid rice. So, it is of significance to study characteristics of floral organs and pollens of several tetraploid rice varieties or lines. Floral organ and pollen characteristics of Sg99012 and HN2026 were studied comparatively by stages and different ploidy levels, with the materials 9311, HD9802S, and PA64S as the control. The results showed that chromosome doubling had much more influence on floral characteristics of every lines than seeding by stages, and the tetraploids of every lines displayed "gigas". In correlation analysis, spikelet length, spikelet width, and anther length had significant correlation; spikelet width and anther width had significant correlation, too. Both seeding by stages and chromosome doubling made the correlations of characters between every floral organ changed to some extent. Seeding by stages had little effect on pollen diameter and fertility of HN2026-4X and Sg99012-4X. But chromosome doubling increased pollen size of every lines remarkably, and also increased the pollen quantity of PMeS (polyploid meiosis stability) restoring line HN2026-4X and gene map restoring line 9311-4X remarkably, whereas only had little effect on that of sterile lines. Moreover, chromosome doubling changed pollen fertility and made the number of fertility pollen of 9311 reduced significantly, but the pollen fertility of HN2026 (PMeS restoring line) and PA64S (sterile line) almost had no change after chromosome doubling. The results showed that tetraploid restoring lines had advantage of abundant and big size pollens, and tetraploid sterile lines had the characters of big size pollens, few change of pollen quantity and stable sterile character. These results provided evidence in reproductive biology for utilizing heterosis of polyploid rice by two-line method.展开更多
基金supported by grants from the 948 Project of the Ministry of Agriculture of China(2013-Z23)the Shanghai Municipal Science Commission of China(10391900100)
文摘The microscopic investigation of the floral development of sweet cherry(Prunus avium L. cv. Hongdeng) from a warm winter climate(Shanghai) and cold winter climate(Tai'an, Shandong Province, China) was conducted to explore the reason of low fruit set. The effect of hydrogen cyanamide(HCN) on floral development under warm winter conditions was also investigated. Trees grown in Shanghai with insufficient chilling accumulation exhibited little difference in the progression of microspore development compared to trees in Tai'an that accumulated adequate chilling, but showed substantial delays in ovule and embryo sac development. The growth of nucelli did not proceed beyond the macrospore mother cell and macrospore stages with abortion rates of 13, 15 and 45% by 6, 3 and 0 d before full bloom, respectively. These abnormalities in the ovule and embryo sac in the Shanghai-grown trees were eliminated by HCN application. These results suggest that chilling regulates the development of female floral organs in winter dormancy; therefore, insufficient chilling accumulation, causing abnormality of the female floral organs, restricts the cultivation of sweet cherry in warm winter regions. Interestingly, HCN application, which decreased the chilling requirements for Hongdeng, may be a potential strategy for sweet cherry cultivation in warm winter regions.
基金Supported by Doctoral Research Start-up Fund(BS514)Inner Mongolia Autonomous Region Science and Technology Reserve Project(2018MDCB02)+1 种基金Inner Mongolia Autonomous Region Science and Technology Planning Project(2018KJJH1702)Scientific Research Project of Inner Mongolia Minzu University(NMDSS2159)。
文摘[Objectives]This study was conducted to explore the mechanism of soybean cytoplasmic-nuclear male sterility.[Methods]With soybean cytoplasmic-nuclear male sterile line JLCMS9 A and its homotype maintainer line JLCMS9 B as experimental materials,the activity of superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT),malondialdehyde(MDA)content,starch content,soluble protein content,soluble sugar content and free proline content in flower buds,alabastrums and mature flowers were determined,and the contents and changes of auxin(IAA),gibberellin(GA3),isopentenyl adenosine(iPA)and abscisic acid(ABA)at the three stages were analyzed.[Results]The activity of SOD and CAT and the contents of MDA and free proline in the sterile line at the flower bud stage were lower than those of the maintainer line,but the opposite was true at the alabastrum stage and the flowering stage,and their values were higher than those of the maintainer line;the POD activity of the sterile line was significantly lower than that of the maintainer line at the flower bud stage,and the opposite was true at the alabastrum stage and the flowering stage,and its values were higher than those of the maintainer line;and the starch content and soluble sugar content of sterile line 9 A showed an overall upward trend,and were significantly lower than those of the maintainer line 9 B at the alabastrum stage and the flowering stage.During the whole development process of floral organs,the content of IAA in sterile line 9 A showed a trend of first increasing and then decreasing,and the content of iPA increased gradually.The contents of hormones in the sterile line were lower than those in the maintainer line.The ratios of IAA/ABA,IAA/GA3,IAA/iPA and ABA/GA3 in the sterile line were significantly different from those in the maintainer line.It is inferred that the abnormal physiological characteristics of floral organ development are related to the cytoplasmic-nuclear male sterility of soybean.The alabastrum stage may be a critical period for the occurrence of abnormal physiological and biochemical indexes in the floral organs of soybean cytoplasmic-nuclear male sterile lines.[Conclusions]This study provides a theoretical basis for the breeding of fine sterile lines of soybean and the research on the mechanism of sterility.
文摘Under the environment of an artificial climate chamber,supercooling point (SCP) and freezing point (FP) in flower and young fruit at different development stages and freezing injuries of floral organs were studied. The apricot cultivars tested were Kety,Golden Sun and Honghebao. With the development of flower buds,SCP and FP increased,which indicated that their cold resistance decreased. SCP and FP varied with different floral organs. For different apricot cultivars,it was found that,the lower SCP or FP in floral organs was,the more resistant capacity the cultivar had,and the larger the temperature interval from SCP to FP was. SCP was not a constant value,but a range. Frequency distribution of SCP in petals was more dispersing than that in stamens and pistils. Floral organs could maintain a supercooling state to avoid ice formation,but they were sensitive to freezing. Once floral organs froze,they turned brown after thawing.
基金Supported by the Scientific and Technological Research Program of Department of Science and Technology of Hubei Province(Q20152903)
文摘This study was conducted to investigate the dynamic changes of several hormones in Rhododendron simsii floral organs to provide theoretical basis for controlling its flowering period.A R.simsii variety " Purple Crane" was selected as the experimental material,and its flower organs were sampled at nine floral developmental stages to measure the contents of gibberellic acid-3( GA_3),abscisic acid( ABA),indole-3-acetic acid( IAA),and zeatin riboside( ZR) through enzyme-linked immunosorbent assay( ELISA).The results showed that the content of ZR was highest at full flowering stage; IAA and GA_3 contents were higher than other stages in the process of flower bud differentiation and flowering.ABA played an important role in the regulation of flower bud formation.The results will provide theoretical references for exploring the regulation of plant hormones towards Rhododendron flower traits and breeding new varieties.
文摘Allelic diversity for five genetic loci (DL, FON4, OsMADS24, OsMADS45 and Spw1) associated with floral organ development were investigated among a small heterogeneous rice population which included one wild species (O. rufipogon Griffiths), one indigenous less popular natural floral organ mutant (O. sativa var. indica cv. Jugal), one indigenous normal line (O. sativa var. indica cv. Bhutmoori) and one improved high yielding line (O. sativa var. indica cv. IR 36). Detailed spikelet morphology showed that var. Jugal had variable number (1 - 3) of carpels within a single spikelet which was unique and resulted in variable (1 - 3) number of kernels within a single matured spikelet (grain). The genomic DNA of each investigated line was amplified with primer sequences designed from the selected genetic loci and the derived polymorphism profiles were used for study of allelic diversity for the studied loci. The derived genetic distances among the rice lines were used for dendrogram construction. In constructed dendrogram, the mutant genotype (Jugal) showed highest similarity with the wild rice (O. rufipogon) instead of the rice lines. To verify this finding, the genomic DNA of each studied line was also amplified with four SSR loci, tightly linked to saltol QTL, mapped to rice chromosome 1. The amplified products were screened for polymorphism and another dendrogram was constructed to reveal the genetic distance among the lines for selected salt tolerance linked SSR loci. In SSR derived dendrogram, the wild rice (O. rufipogon) got totally separated from the all three rice genotypes though all the studied four lines showed equal sensitivity for salt sensitivity in a physiological screening experiment. From the combined experiment, it can be concluded that genetic architecture of floral organ development loci in var. Jugal may have some uniqueness which is not present in normal rice but common to O. rufipogon, a species which is regarded as immediate progenitor of present day modern rice (O. sativa). Though this uniqueness was not confirmed by second set genetic loci associated with salt tolerance in rice, the information resulted from this experiment was preliminary and based only on allelic size (molecular weight of amplicon), which should be confirmed through sequence analysis for further analysis.
文摘A rice floral organ mutant, srs2, derived from a spontaneous mutation, was first discovered in a japonica rice variety GNZ. The mutant displayed various abnormalities in floral organ including longer paleas/lemmas, split spikelets, palea/lemma-like lodicules, two florets of the same rachilla, a decrease in stamen number, and an increase in pistil number. Moreover, the seed-setting rate of the mutant was also reduced to 9.8%. Observations of the floral organ morphogenesis by a scanning electron microscope (SEM) in the mutant indicated that the development of androecium and gynoecia was abnormal and an additional floret and several palea/lemma-like lodicules were usually formed by the irregular development of the floral meristem. Genetic analysis of 4 F2 and 2 BC1F1 populations showed that the mutation was controlled by a single recessive gene, and designated as srs2 (spit rice spikelet 2). Screening of 643 F2 mutant individuals derived from the cross of srs2 × 202R with simple sequence repeat (SSR) markers demonstrated that SRS2 is located between the molecular marker S31 and L75, at a distances of 0.07 and 2 cM, respectively, on chromosome 3. The SRS2 gene was also discussed to be a new floral organ identity gene in rice.
基金Supported by Special Fund for Bulk Vegetable Innovation Team of Guangxi Zhuang Autonomous Region from National Modern Agriculture Industry Technology System(nycytxgxcxtd-03-10-1)Natural Science Foundation of Guangxi Zhuang Autonomous Region(2011GXNSFB018033)+2 种基金Science and Technology Development Fund of Guangxi Academy of Agricultural Sciences(201001)Key Project of Science and Technology of Guangxi Zhuang Autonomous Region(GKG 0323001-1)Project of Nanning Bureau of Science and Technology(201102057B)
文摘[Objective]This study aimed to investigate various factors affecting the dedifferentiation of different floral organs of Jinxiu wild chive.[Method]Floral organs of Jinxiu wild chive were cultured in vitro,to analyze the effects of basic medium,exogenous hormone type and combination,and blossoming status of buds on callus induction.[Result]MS medium was the most suitable medium for callus induction from buds.NAA was conducive to improving callus formation rate compared with other auxins.Non-blossomed buds exhibited the highest rate of callus induction.Under the same culture conditions,the rate of callus induction varied extremely significantly among various floral organs;to be specific,the rate of callus induction from floral disc reached the highest,followed successively by bud and pedicel,but no callus was formed in floral axis group.[Conclusion]This study laid the foundation for further establishment of tissue culture and rapid propagation system of Jinxiu wild chive and other wild chives and provided technical support for the preservation,development and utilization of wild chive germplasm resources.
文摘A spontaneous rice mutant named floral organ number 3 (fon3) had major mutations in floral organ numbers. Genetic analysis indicated thatfon3 acted as a single recessive gene. Microscopic observation showed that the number of floral organs infon3 increased centripetally. For example, the number of pistils was the more frequently increased than organs in the outer whorls. Homeotic conversion of lodicules and glumes into palea/lemma-like organs was observed in some flowers. Scanning electron microscopy observation showed that the size of flower meristems was maintained the same or similar until the lemma primordium started to differentiate, at which time the floral meristem became enlarged, suggesting abnormal development of the inner whorls of rice florets. The relationship offon3 with other similar rice mutants is discussed.
基金Supported by the National Natural Science Foundation of China (30225007)the Natural Science Foundation of Yunnan Province,China (2005C0057M)
文摘Current understanding of the classical ABC model of floral development has provided a new set of characters to evaluate floral evolution. However, what is still lacking is a clear assessment of this genetic program across monocots. Here, to investigate the evolution of members of class A and B genes in monocots, we report the sequence characteristic and transcript expression of three new MADS-box genes in Alpinia oblongifolia Hayata. Sequence and phylogenetic analysis reveals that these genes are FUL-like and AP3-like. Therefore, they were termed AoFL1, AoFL2 and AoAP3. AoFL1 contains the FUL motif, but AoFL2 lacks this motif. Their expression revealed by in situ hybridization may reflect the ancestral function of FUL-like genes in the specification of inflorescence and floral meristems. The AoAP3 gene contains two conserved motifs, the PI-derived and paleoAP3 motifs. The AoAP3 transcripts located to the corolla and stamen, and hybridization signals were detected in the central whorl. These expression patterns suggest that the functions of homologous organ identity genes are diversified in A. oblongifolia. The implications of these findings on the conservation of homologous gene function are discussed.
基金funded by the National Natural Sciences Foundation of China (39970447, 30240090,30471063, 30650002)the Natural Science Foundation of Hubei Province, China (2005ABA198)the Key Program of Hubei Provincial Department of Education,China (2000Z01010)
文摘Polyploidization is the evolution trend of many crops, and the yield increased obviously after polyploidization. The polyploidization of rice often brings "gigas" of both vegetative organs and seeds. Howevere, in rice breeding, it is required for restoring lines to have not only big anthers but also abundant pollens. People often doubt that the enlargement of the floral organ may just be enlargement of cell size in polyploid rice. So, it is of significance to study characteristics of floral organs and pollens of several tetraploid rice varieties or lines. Floral organ and pollen characteristics of Sg99012 and HN2026 were studied comparatively by stages and different ploidy levels, with the materials 9311, HD9802S, and PA64S as the control. The results showed that chromosome doubling had much more influence on floral characteristics of every lines than seeding by stages, and the tetraploids of every lines displayed "gigas". In correlation analysis, spikelet length, spikelet width, and anther length had significant correlation; spikelet width and anther width had significant correlation, too. Both seeding by stages and chromosome doubling made the correlations of characters between every floral organ changed to some extent. Seeding by stages had little effect on pollen diameter and fertility of HN2026-4X and Sg99012-4X. But chromosome doubling increased pollen size of every lines remarkably, and also increased the pollen quantity of PMeS (polyploid meiosis stability) restoring line HN2026-4X and gene map restoring line 9311-4X remarkably, whereas only had little effect on that of sterile lines. Moreover, chromosome doubling changed pollen fertility and made the number of fertility pollen of 9311 reduced significantly, but the pollen fertility of HN2026 (PMeS restoring line) and PA64S (sterile line) almost had no change after chromosome doubling. The results showed that tetraploid restoring lines had advantage of abundant and big size pollens, and tetraploid sterile lines had the characters of big size pollens, few change of pollen quantity and stable sterile character. These results provided evidence in reproductive biology for utilizing heterosis of polyploid rice by two-line method.
