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资助项目
6 could use lots of photosynthates, but contributed little to the accumulation of biomass. 4. Photosynthetic rate of P. armeniacum decreased a little at the noon, and the highest photosynthetic rate was observed at 10:00h in the greenhouse. The variation of photosynthetic rate was in the same trend as stomatal conductance. Higher relative humidity seemed to be the key for higher photosynthetic rate in P. armeniacum. 5. The photosynthetic capacity of C. flavum was statistically larger than that of P. armeniacum. The lower leaf photosynthetic capacity of P. armeniacum was related to its lower leaf nitrogen concentration,leaf phosphorus concentration and enzyme activities. Meanwhile, the extremely lower stomatal conductance and internal mesophyll conductance might greatly limit the photosynthetic capacity of P. armeniacum. The lower stomatal conductance and photosynthetic rate of Paphiopedilum might partially caused by the lack of chloroplasts in the guard cell of Paphiopedilum. Compared with C. flavum, P. armeniacum was more fond of shade environment.6. The short longevity leaf of Cypripedium had bigger photosynthetic capacity and greater potential for fast growth. But the longer LL of Paphiopedilum enhanced nutrient conservation which could compensate its lower photosynthetic capacity. The short longevity leaf of Cypripedium usually had higher photosynthetic rate per unit leaf mass and dark respiration rate, and photosynthetic capacity decreased fast with leaf age. However, for Paphiopedilum, the situation was the opposite. 7. Compared with Cypripedium, Paphiopedilum had higher water use efficiency and lower photosynthetic nitrogen use efficiency. 8. The leaf of Paphiopedilum had higher leaf construction cost and longer repayment time than that of Cypripedium. The leaf structures and physiological functions of Paphiopedilum and Cypripedium reflected the adaptation to their habitats. The leaf morphological and physiological evolution of Paphiopedilum was related to water and resource-conserving traits in the karst habitat. The leaf traits of Cypripedium were the adaptation to the environment rich in water and nutrients but easy to change with seasons.Our results provided evidence of divergent evolution of congeneric orchids under natural selection.","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.citation.source_filter&advanced=false&fq=dc.language.iso_filter%3A%E4%B8%AD%E6%96%87&query1=ELEMENT&&fq=dc.project.title_filter%3APaphiopedilum%5C+and%5C+Cypripedium%5C+are%5C+close%5C+relatives%5C+belonging%5C+to%5C+the%5C+subfamily%5C+Cypripedioideae.%5C+However%2C%5C+they%5C+undergo%5C+considerable%5C+divergence%5C+in%5C+the%5C+aspects%5C+of%5C+life%5C+forms%2C%5C+leaf%5C+traits%5C+and%5C+habitats.%5C+In%5C+present%5C+study%2C%5C+leaf%5C+morphologies%5C+and%5C+anatomical%5C+structures%2C%5C+leaf%5C+lifespans%2C%5C+leaf%5C+mass%5C+per%5C+area%2C%5C+photosynthetic%5C+capacities%2C%5C+nutrient%5C+use%5C+efficiencies%2C%5C+leaf%5C+construction%5C+costs%2C%5C+and%5C+maintenance%5C+costs%5C+were%5C+investigated%5C+to%5C+understand%5C+the%5C+relationship%5C+between%5C+leaf%5C+traits%5C+and%5C+ecophysiological%5C+adaptability%5C+of%5C+the%5C+two%5C+types%5C+of%5C+plants%5C+and%5C+explore%5C+the%5C+related%5C+ecological%5C+and%5C+evolutionary%5C+significances.%5C+The%5C+results%5C+suggest%5C+that%5C%3A1.%5C+Compared%5C+with%5C+Cypripedium%2C%5C+Paphiopedilum%5C+was%5C+characterized%5C+by%5C+drought%5C+tolerance%5C+from%5C+its%5C+leaf%5C+anatomical%5C+structure%5C+including%5C+fleshy%5C+leaf%2C%5C+thicker%5C+surface%5C+cuticle%2C%5C+huge%5C+abaxial%5C+epidermis%5C+cells%2C%5C+differentiation%5C+of%5C+palisade%5C+and%5C+spongy%5C+mesophyll%5C+layers%2C%5C+the%5C+prominent%5C+of%5C+mucilaginous%5C+substances%2C%5C+supportable%5C+leaf%5C+main%5C+vein%2C%5C+lower%5C+total%5C+stoma%5C+area%5C+%5C%28%25%5C%29%2C%5C+sunken%5C+stomata%5C+and%5C+special%5C+stoma%5C+structure.%5C+Leaf%5C+morphologies%5C+and%5C+structures%5C+of%5C+Cypripedium%5C+were%5C+to%5C+the%5C+contrary%5C+of%5C+Paphiopedilum.%5C+Leaf%5C+morphologies%5C+and%5C+structures%5C+embodied%5C+the%5C+adaptation%5C+to%5C+the%5C+environment%5C+in%5C+both%5C+Paphiopedilum%5C+and%5C+Cypripedium.%5C+Our%5C+results%5C+also%5C+confirmed%5C+the%5C+previous%5C+observation%5C+that%5C+Paphiopedilum%5C+was%5C+the%5C+only%5C+genus%5C+that%5C+did%5C+not%5C+possess%5C+guard%5C+cell%5C+chloroplasts.2.%5C+The%5C+photosynthetic%5C+capacities%5C+of%5C+P.%5C+armeniacum%5C+leaves%5C+were%5C+different%5C+with%5C+different%5C+leaf%5C+ages.%5C+The%5C+highest%5C+photosynthetic%5C+capacity%5C+occurred%5C+in%5C+leaf%5C+age%5C+1%5C-2%5C+years%2C%5C+followed%5C+by%5C+1%5C+year%5C+and%5C+2%5C-4%5C+years.%5C+The%5C+highest%5C+photosynthetic%5C+capacity%5C+of%5C+C.%5C+flavum%5C+occurred%5C+in%5C+leaf%5C+age%5C+60%5C+days%2C%5C+followed%5C+by%5C+30%5C+days%2C%5C+90%5C+days%5C+and%5C+120%5C+days.%5C+3.%5C+Photosynthetic%5C+capacities%5C+of%5C+different%5C+leaf%5C+positions%5C+were%5C+mainly%5C+affected%5C+by%5C+leaf%5C+ages%5C+in%5C+P.%5C+armeniacum.%5C+The%5C+four%5C+leaves%5C+lying%5C+on%5C+the%5C+top%5C+did%5C+the%5C+most%5C+accumulation%5C+of%5C+the%5C+assimilation%5C+products%5C+in%5C+the%5C+whole%5C+plant.%5C+The%5C+leaves%5C+of%5C+sequence%5C+number%5C+%3E%5C+6%5C+could%5C+use%5C+lots%5C+of%5C+photosynthates%2C%5C+but%5C+contributed%5C+little%5C+to%5C+the%5C+accumulation%5C+of%5C+biomass.%5C+4.%5C+Photosynthetic%5C+rate%5C+of%5C+P.%5C+armeniacum%5C+decreased%5C+a%5C+little%5C+at%5C+the%5C+noon%2C%5C+and%5C+the%5C+highest%5C+photosynthetic%5C+rate%5C+was%5C+observed%5C+at%5C+10%5C%3A00h%5C+in%5C+the%5C+greenhouse.%5C+The%5C+variation%5C+of%5C+photosynthetic%5C+rate%5C+was%5C+in%5C+the%5C+same%5C+trend%5C+as%5C+stomatal%5C+conductance.%5C+Higher%5C+relative%5C+humidity%5C+seemed%5C+to%5C+be%5C+the%5C+key%5C+for%5C+higher%5C+photosynthetic%5C+rate%5C+in%5C+P.%5C+armeniacum.%5C+5.%5C+The%5C+photosynthetic%5C+capacity%5C+of%5C+C.%5C+flavum%5C+was%5C+statistically%5C+larger%5C+than%5C+that%5C+of%5C+P.%5C+armeniacum.%5C+The%5C+lower%5C+leaf%5C+photosynthetic%5C+capacity%5C+of%5C+P.%5C+armeniacum%5C+was%5C+related%5C+to%5C+its%5C+lower%5C+leaf%5C+nitrogen%5C+concentration%2Cleaf%5C+phosphorus%5C+concentration%5C+and%5C+enzyme%5C+activities.%5C+Meanwhile%2C%5C+the%5C+extremely%5C+lower%5C+stomatal%5C+conductance%5C+and%5C+internal%5C+mesophyll%5C+conductance%5C+might%5C+greatly%5C+limit%5C+the%5C+photosynthetic%5C+capacity%5C+of%5C+P.%5C+armeniacum.%5C+The%5C+lower%5C+stomatal%5C+conductance%5C+and%5C+photosynthetic%5C+rate%5C+of%5C+Paphiopedilum%5C+might%5C+partially%5C+caused%5C+by%5C+the%5C+lack%5C+of%5C+chloroplasts%5C+in%5C+the%5C+guard%5C+cell%5C+of%5C+Paphiopedilum.%5C+Compared%5C+with%5C+C.%5C+flavum%2C%5C+P.%5C+armeniacum%5C+was%5C+more%5C+fond%5C+of%5C+shade%5C+environment.6.%5C+The%5C+short%5C+longevity%5C+leaf%5C+of%5C+Cypripedium%5C+had%5C+bigger%5C+photosynthetic%5C+capacity%5C+and%5C+greater%5C+potential%5C+for%5C+fast%5C+growth.%5C+But%5C+the%5C+longer%5C+LL%5C+of%5C+Paphiopedilum%5C+enhanced%5C+nutrient%5C+conservation%5C+which%5C+could%5C+compensate%5C+its%5C+lower%5C+photosynthetic%5C+capacity.%5C+The%5C+short%5C+longevity%5C+leaf%5C+of%5C+Cypripedium%5C+usually%5C+had%5C+higher%5C+photosynthetic%5C+rate%5C+per%5C+unit%5C+leaf%5C+mass%5C+and%5C+dark%5C+respiration%5C+rate%2C%5C+and%5C+photosynthetic%5C+capacity%5C+decreased%5C+fast%5C+with%5C+leaf%5C+age.%5C+However%2C%5C+for%5C+Paphiopedilum%2C%5C+the%5C+situation%5C+was%5C+the%5C+opposite.%5C+7.%5C+Compared%5C+with%5C+Cypripedium%2C%5C+Paphiopedilum%5C+had%5C+higher%5C+water%5C+use%5C+efficiency%5C+and%5C+lower%5C+photosynthetic%5C+nitrogen%5C+use%5C+efficiency.%5C+8.%5C+The%5C+leaf%5C+of%5C+Paphiopedilum%5C+had%5C+higher%5C+leaf%5C+construction%5C+cost%5C+and%5C+longer%5C+repayment%5C+time%5C+than%5C+that%5C+of%5C+Cypripedium.%5C+The%5C+leaf%5C+structures%5C+and%5C+physiological%5C+functions%5C+of%5C+Paphiopedilum%5C+and%5C+Cypripedium%5C+reflected%5C+the%5C+adaptation%5C+to%5C+their%5C+habitats.%5C+The%5C+leaf%5C+morphological%5C+and%5C+physiological%5C+evolution%5C+of%5C+Paphiopedilum%5C+was%5C+related%5C+to%5C+water%5C+and%5C+resource%5C-conserving%5C+traits%5C+in%5C+the%5C+karst%5C+habitat.%5C+The%5C+leaf%5C+traits%5C+of%5C+Cypripedium%5C+were%5C+the%5C+adaptation%5C+to%5C+the%5C+environment%5C+rich%5C+in%5C+water%5C+and%5C+nutrients%5C+but%5C+easy%5C+to%5C+change%5C+with%5C+seasons.Our%5C+results%5C+provided%5C+evidence%5C+of%5C+divergent%5C+evolution%5C+of%5C+congeneric%5C+orchids%5C+under%5C+natural%5C+selection."},{"jsname":"Seeds contain the entire genetic information of plants, which enable to develop the technology of seed preservation for the conservation of plant diversity. The mechanism of cell death in seeds, which are induced by ageing of orthodox seeds and desiccation of recalcitrant and intermediate seeds are two important areas in seed biology but poorly understood.Those two areas were investigated in this dissertation, and Pisum sativum, Camellia sinensis var. assamica, Castanea mollissima were chosen to represent orthodox, intermediate and recalcitrant seeds respectively as studied models. Biophysical, biochemical and molecular methods were employed to investigate the cell death mechanism during seeds ageing and desiccation.First of all, Ageing induced porgrammed cell death in seeds.The morphology change, nucleic acid integrity, and gene expression during ageing of Pisum sativum seeds were investigated.The data above confirmed that PCD is an underlying mechanism of seed mortality. Moreover, glutathione played an important function during seeds ageing.An increase in glutathione redox potential (EGSSG/2GSH) while seed lost viability was discovered during ageing of P. sativum seeds. Seed viability decreased 50% when EGSSG/2GSH attained values of -180 to -160 mV, which proved that EGSSG/2GSH was a marker for seeds viability. Secondely,Reactive oxygen species plays different roles in the seed germination after desiccation. After different desiccation treatments on the tea (C. sinensis var. assamica) seeds, the relationship between ROS dose and the viability of seeds after desication treatment was investigated. The results demonstrated that the presence of ROS could released the damage of desiccation on the tea seeds. Thridly,the composition of membrane lipid species and the change during desiccation in seeds with different storage behavior. Cell membrane is very sensitive to environment, and adjust the composition of lipid molecules is one of the main methord for cell to response the environmental changes. There is a rule that phosphatidic acid (PA), with special structure, is very sensitive to temperature and water stress, and the increase of PA content indicates the damage of the cell membrane. ESI/MS-MS technology was used to analysis and compare the composition and changes membrane lipid species during desiccation treatments of Pisum sativum, Camellia sinensis var. assamica, Castanea mollissima seeds which represented orthodox, intermediate and recalcitrant seeds respectively. The results showed that the responses of PA to dehydration in embryonic axis of orhtordox and recalcitrant seeds were different. The percentage increasement of PA in orthodox seed during desiccation was not incredible and the level of PA decreased and achieved the same level as controled, while PA level increased dramatically without showing any decrease trend in recalcitrant seed, which indicated that the damage to membrane of recalcitrant seeds was inevitable. Those results indicted that the dehydration might induced reversible memebrane damage in the orthodox seed, which may result in no affect on the seed viability, while it might induced irreversible membrane damage to the recalcitrant seed, which inducned the dramatically reduce of viabiligy and cell death in the end. It was the first time to investigate and analysis systematically the composition and changes of membrane lipids of different storage behavior seeds during desiccation. It was first time to report the relationship between PA and the seeds storeage and the change of PA level in seeds could be used as the marker to diagnose.the property of seeds for desiccation sensitivity or desiccation tolerance","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.citation.source_filter&advanced=false&fq=dc.language.iso_filter%3A%E4%B8%AD%E6%96%87&query1=ELEMENT&&fq=dc.project.title_filter%3ASeeds%5C+contain%5C+the%5C+entire%5C+genetic%5C+information%5C+of%5C+plants%2C%5C+which%5C+enable%5C+to%5C+develop%5C+the%5C+technology%5C+of%5C+seed%5C+preservation%5C+for%5C+the%5C+conservation%5C+of%5C+plant%5C+diversity.%5C+The%5C+mechanism%5C+of%5C+cell%5C+death%5C+in%5C+seeds%2C%5C+which%5C+are%5C+induced%5C+by%5C+ageing%5C+of%5C+orthodox%5C+seeds%5C+and%5C+desiccation%5C+of%5C+recalcitrant%5C+and%5C+intermediate%5C+seeds%5C+are%5C+two%5C+important%5C+areas%5C+in%5C+seed%5C+biology%5C+but%5C+poorly%5C+understood.Those%5C+two%5C+areas%5C+were%5C+investigated%5C+in%5C+this%5C+dissertation%2C%5C+and%5C+Pisum%5C+sativum%2C%5C+Camellia%5C+sinensis%5C+var.%5C+assamica%2C%5C+Castanea%5C+mollissima%5C+were%5C+chosen%5C+to%5C+represent%5C+orthodox%2C%5C+intermediate%5C+and%5C+recalcitrant%5C+seeds%5C+respectively%5C+as%5C+studied%5C+models.%5C+Biophysical%2C%5C+biochemical%5C+and%5C+molecular%5C+methods%5C+were%5C+employed%5C+to%5C+investigate%5C+the%5C+cell%5C+death%5C+mechanism%5C+during%5C+seeds%5C+ageing%5C+and%5C+desiccation.First%5C+of%5C+all%2C%5C+Ageing%5C+induced%5C+porgrammed%5C+cell%5C+death%5C+in%5C+seeds.The%5C+morphology%5C+change%2C%5C+nucleic%5C+acid%5C+integrity%2C%5C+and%5C+gene%5C+expression%5C+during%5C+ageing%5C+of%5C+Pisum%5C+sativum%5C+seeds%5C+were%5C+investigated.The%5C+data%5C+above%5C+confirmed%5C+that%5C+PCD%5C+is%5C+an%5C+underlying%5C+mechanism%5C+of%5C+seed%5C+mortality.%5C+Moreover%2C%5C+glutathione%5C+played%5C+an%5C+important%5C+function%5C+during%5C+seeds%5C+ageing.An%5C+increase%5C+in%5C+glutathione%5C+redox%5C+potential%5C+%5C%28EGSSG%5C%2F2GSH%5C%29%5C+while%5C+seed%5C+lost%5C+viability%5C+was%5C+discovered%5C+during%5C+ageing%5C+of%5C+P.%5C+sativum%5C+seeds.%5C+Seed%5C+viability%5C+decreased%5C+50%25%5C+when%5C+EGSSG%5C%2F2GSH%5C+attained%5C+values%5C+of%5C+%5C-180%5C+to%5C+%5C-160%5C+mV%2C%5C+which%5C+proved%5C+that%5C+EGSSG%5C%2F2GSH%5C+was%5C+a%5C+marker%5C+for%5C+seeds%5C+viability.%5C+Secondely%2CReactive%5C+oxygen%5C+species%5C+plays%5C+different%5C+roles%5C+in%5C+the%5C+seed%5C+germination%5C+after%5C+desiccation.%5C+After%5C+different%5C+desiccation%5C+treatments%5C+on%5C+the%5C+tea%5C+%5C%28C.%5C+sinensis%5C+var.%5C+assamica%5C%29%5C+seeds%2C%5C+the%5C+relationship%5C+between%5C+ROS%5C+dose%5C+and%5C+the%5C+viability%5C+of%5C+seeds%5C+after%5C+desication%5C+treatment%5C+was%5C+investigated.%5C+The%5C+results%5C+demonstrated%5C+that%5C+the%5C+presence%5C+of%5C+ROS%5C+could%5C+released%5C+the%5C+damage%5C+of%5C+desiccation%5C+on%5C+the%5C+tea%5C+seeds.%5C+Thridly%2Cthe%5C+composition%5C+of%5C+membrane%5C+lipid%5C+species%5C+and%5C+the%5C+change%5C+during%5C+desiccation%5C+in%5C+seeds%5C+with%5C+different%5C+storage%5C+behavior.%5C+Cell%5C+membrane%5C+is%5C+very%5C+sensitive%5C+to%5C+environment%2C%5C+and%5C+adjust%5C+the%5C+composition%5C+of%5C+lipid%5C+molecules%5C+is%5C+one%5C+of%5C+the%5C+main%5C+methord%5C+for%5C+cell%5C+to%5C+response%5C+the%5C+environmental%5C+changes.%5C+There%5C+is%5C+a%5C+rule%5C+that%5C+phosphatidic%5C+acid%5C+%5C%28PA%5C%29%2C%5C+with%5C+special%5C+structure%2C%5C+is%5C+very%5C+sensitive%5C+to%5C+temperature%5C+and%5C+water%5C+stress%2C%5C+and%5C+the%5C+increase%5C+of%5C+PA%5C+content%5C+indicates%5C+the%5C+damage%5C+of%5C+the%5C+cell%5C+membrane.%5C+ESI%5C%2FMS%5C-MS%5C+technology%5C+was%5C+used%5C+to%5C+analysis%5C+and%5C+compare%5C+the%5C+composition%5C+and%5C+changes%C2%A0membrane%5C+lipid%5C+species%5C+during%5C+desiccation%5C+treatments%5C+of%5C+Pisum%5C+sativum%2C%5C+Camellia%5C+sinensis%5C+var.%5C+assamica%2C%5C+Castanea%5C+mollissima%5C+seeds%5C+which%5C+represented%5C+orthodox%2C%5C+intermediate%5C+and%5C+recalcitrant%5C+seeds%5C+respectively.%5C+The%5C+results%5C+showed%5C+that%5C+the%5C+responses%5C+of%5C+PA%5C+to%5C+dehydration%5C+in%5C+embryonic%5C+axis%5C+of%5C+orhtordox%5C+and%5C+recalcitrant%5C+seeds%5C+were%5C+different.%5C+The%5C+percentage%5C+increasement%5C+of%5C+PA%5C+in%5C+orthodox%5C+seed%5C+during%5C+desiccation%5C+was%5C+not%5C+incredible%5C+and%5C+the%5C+level%5C+of%5C+PA%5C+decreased%5C+and%5C+achieved%5C+the%5C+same%5C+level%5C+as%5C+controled%2C%5C+while%5C+PA%5C+level%5C+increased%5C+dramatically%5C+without%5C+showing%5C+any%5C+decrease%5C+trend%5C+in%5C+recalcitrant%5C+seed%2C%5C+which%5C+indicated%5C+that%5C+the%5C+damage%5C+to%5C+membrane%5C+of%5C+recalcitrant%5C+seeds%5C+was%5C+inevitable.%C2%A0Those%5C+results%5C+indicted%5C+that%5C+the%5C+dehydration%5C+might%5C+induced%5C+reversible%5C+memebrane%5C+damage%5C+in%5C+the%5C+orthodox%5C+seed%2C%5C+which%5C+may%5C+result%5C+in%5C+no%5C+affect%5C+on%5C+the%5C+seed%5C+viability%2C%5C+while%5C+it%5C+might%5C+induced%5C+irreversible%5C+membrane%5C+damage%5C+to%5C+the%5C+recalcitrant%5C+seed%2C%5C+which%5C+inducned%5C+the%5C+dramatically%5C+reduce%5C+of%5C+viabiligy%5C+and%5C+cell%5C+death%5C+in%5C+the%5C+end.%5C+It%5C+was%5C+the%5C+first%5C+time%5C+to%5C+investigate%5C+and%5C+analysis%5C+systematically%5C+the%5C+composition%5C+and%5C+changes%5C+of%5C+membrane%5C+lipids%5C+of%5C+different%5C+storage%5C+behavior%5C+seeds%5C+during%5C+desiccation.%5C+It%5C+was%5C+first%5C+time%5C+to%5C+report%5C+the%5C+relationship%5C+between%5C+PA%5C+and%5C+the%5C+seeds%5C+storeage%5C+and%5C+the%5C+change%5C+of%5C+PA%5C+level%5C+in%5C+seeds%5C+could%5C+be%5C+used%5C+as%5C+the%5C+marker%5C+to%5C+diagnose.the%5C+property%5C+of%5C+seeds%5C+for%5C+desiccation%5C+sensitivity%5C+or%5C+desiccation%5C+tolerance"},{"jsname":"Transposable elements (TEs) have been found to be a significant fraction of eukaryotic genomes. Moreover, they make great contributions to the structure, function and evolution of genomes as well as genes. However, some questions such as the mechanisms of retainment of TEs in the genome and their adaptive evolution have not been fully elucidated so far. In this study, the distributions of 17 TE-gene associations among Oryza species were investigated. In addition, the nucleotide diversity was analysed and neutral tests for the region flanking the TE insertions were performed. Based on the above-observed patterns, evolutionary relationships between species in the AA genome group were discussed. The main results are as follows: For each TE-gene association, PCR and electrophoresis were conducted for a total of 107 strains, belonging to different Oryza species. The patterns of each TE-gene association in different species were obtained. It is our finding that 2 associations distribute through all Oryza species. By contrast, other 15 associations were only observed in some Oryza species. On basis of the above-mentioned results, it is likely that insertion events under study occurred in their common ancestor, and then they dispersed with subsequent divergence of different AA genome species. Our datas strongly support that O. meridionalis is the most basal lineage of AA genome group, instead of O. longistaminata.For several TE-gene associations fixed in populations of ancestor, the nucleotide diversity was estimated and neutral tests for the region flanking the TE insertions between populations with and without TE insertions were performed. No significant result was obtained. It is possible that the fixation of mutations with TE insetion is a random process; alternatively, this process is attributable to nature selection. Since the fixation has finished, it is difficult to detect the signature at the sequence level.","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.citation.source_filter&advanced=false&fq=dc.language.iso_filter%3A%E4%B8%AD%E6%96%87&query1=ELEMENT&&fq=dc.project.title_filter%3ATransposable%5C+elements%5C+%5C%28TEs%5C%29%5C+have%5C+been%5C+found%5C+to%5C+be%5C+a%5C+significant%5C+fraction%5C+of%5C+eukaryotic%5C+genomes.%5C+Moreover%2C%5C+they%5C+make%5C+great%5C+contributions%5C+to%5C+the%5C+structure%2C%5C+function%5C+and%5C+evolution%5C+of%5C+genomes%5C+as%5C+well%5C+as%5C+genes.%5C+However%2C%5C+some%5C+questions%5C+such%5C+as%5C+the%5C+mechanisms%5C+of%5C+retainment%5C+of%5C+TEs%5C+in%5C+the%5C+genome%5C+and%5C+their%5C+adaptive%5C+evolution%5C+have%5C+not%5C+been%5C+fully%5C+elucidated%5C+so%5C+far.%5C+In%5C+this%5C+study%2C%5C+the%5C+distributions%5C+of%5C+17%5C+TE%5C-gene%5C+associations%5C+among%5C+Oryza%5C+species%5C+were%5C+investigated.%5C+In%5C+addition%2C%5C+the%5C+nucleotide%5C+diversity%5C+was%5C+analysed%5C+and%5C+neutral%5C+tests%5C+for%5C+the%5C+region%5C+flanking%5C+the%5C+TE%5C+insertions%5C+were%5C+performed.%5C+Based%5C+on%5C+the%5C+above%5C-observed%5C+patterns%2C%5C+evolutionary%5C+relationships%5C+between%5C+species%5C+in%5C+the%5C+AA%5C+genome%5C+group%5C+were%5C+discussed.%5C+The%5C+main%5C+results%5C+are%5C+as%5C+follows%5C%3A%5C+For%5C+each%5C+TE%5C-gene%5C+association%2C%5C+PCR%5C+and%5C+electrophoresis%5C+were%5C+conducted%5C+for%5C+a%5C+total%5C+of%5C+107%5C+strains%2C%5C+belonging%5C+to%5C+different%5C+Oryza%5C+species.%5C+The%5C+patterns%5C+of%5C+each%5C+TE%5C-gene%5C+association%5C+in%5C+different%5C+species%5C+were%5C+obtained.%5C+It%5C+is%5C+our%5C+finding%5C+that%5C+2%5C+associations%5C+distribute%5C+through%5C+all%5C+Oryza%5C+species.%5C+By%5C+contrast%2C%5C+other%5C+15%5C+associations%5C+were%5C+only%5C+observed%5C+in%5C+some%5C+Oryza%5C+species.%5C+On%5C+basis%5C+of%5C+the%5C+above%5C-mentioned%5C+results%2C%5C+it%5C+is%5C+likely%5C+that%5C+insertion%5C+events%5C+under%5C+study%5C+occurred%5C+in%5C+their%5C+common%5C+ancestor%2C%5C+and%5C+then%5C+they%5C+dispersed%5C+with%5C+subsequent%5C+divergence%5C+of%5C+different%5C+AA%5C+genome%5C+species.%5C+Our%5C+datas%5C+strongly%5C+support%5C+that%5C+O.%5C+meridionalis%5C+is%5C+the%5C+most%5C+basal%5C+lineage%5C+of%5C+AA%5C+genome%5C+group%2C%5C+instead%5C+of%5C+O.%5C+longistaminata.For%5C+several%5C+TE%5C-gene%5C+associations%5C+fixed%5C+in%5C+populations%5C+of%5C+ancestor%2C%5C+the%5C+nucleotide%5C+diversity%5C+was%5C+estimated%5C+and%5C+neutral%5C+tests%5C+for%5C+the%5C+region%5C+flanking%5C+the%5C+TE%5C+insertions%5C+between%5C+populations%5C+with%5C+and%5C+without%5C+TE%5C+insertions%5C+were%5C+performed.%5C+No%5C+significant%5C+result%5C+was%5C+obtained.%5C+It%5C+is%5C+possible%5C+that%5C+the%5C+fixation%5C+of%5C+mutations%5C+with%5C+TE%5C+insetion%5C+is%5C+a%5C+random%5C+process%5C%3B%5C+alternatively%2C%5C+this%5C+process%5C+is%5C+attributable%5C+to%5C+nature%5C+selection.%5C+Since%5C+the%5C+fixation%5C+has%5C+finished%2C%5C+it%5C+is%5C+difficult%5C+to%5C+detect%5C+the%5C+signature%5C+at%5C+the%5C+sequence%5C+level."},{"jsname":"lastIndexed","jscount":"2024-05-05"}],"资助项目","dc.project.title_filter")'>
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