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Two ancient rounds of polyploidy in rice genome 总被引：10，自引：0，他引：10
An ancient genome duplication (PPP1) that predates divergence ofthe cereals has recently been recognized. We report here another potentially older large-scale duplication (PPP2) event that predates monocot-dicot divergence in the genome of rice(Oryza saliva L.), as inferred from the age distribution of pairs of duplicate genes based on recent genome data for rice. Our results suggest that paleopolyploidy was widespread and played an important role in the evolution of rice. 相似文献
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INTRODUCTIONCorrectlypinpointingsplicing sitesingenomicDNAsequencesisnotaneasytask ,whichisofgreatimportancetothegenomeannotationandgenefinding .Intronsaregenerallydividedinto3classes,namelycalssI,classIIandcommonnu cleuspre mRNA .IntronofclassIandIIcango… 相似文献
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INTRODUCTION Cytokinins play a major role in many differentdevelopmental and physiological plant processes,such as cell division, regulation of root and shootgrowth and branching, chloroplast development,leaf senescence, stress response and pathogen re-sistance (Mok and Mok, 2001). Significant ad-vances have been achieved in our understanding ofcytokinin signaling, providing important insightsinto the molecular partners involved (Hutchisonand Kieber, 2002; Sheen, 2002). It had been… 相似文献
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INTRODUCTIONAfterthewholericegenomewassequencedsuccessfully,moreandmoregenescanbepredictedwithdifferentsoftwaresandannotationsystem.However,thefunctionsofpredictedgeneshavetobefurtheridentifiedbybiologicalanalysis.Oneofthemostpowerfulmethodsassigningfunctiontogeneisthroughinsertionmutagenesiswithtrans-posableelementasDNAsequencetag.Ac/Dstrans-posonsystemhasbecomeaverypopulartoolforgenetaggingandfunctionalgenomicsinvariousplantspecies(Altmannetal.,1995;Chinetal.,1999;Enokietal.,1999;Gre… 相似文献
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水稻在大孢子发生期间,珠心细胞保留了较多的分生组织细胞的特征:其细胞形态规则,细胞质浓厚,富含核糖体。核糖体游离于细胞质中,或附着于内质网及核外膜上。酸性磷酸酶的反应产物主要位于小液泡中,偶见于高尔基潴泡及小泡中。随着胚囊的分化,在珠心的内层出现一系列复杂的变化:①在细胞的液泡化过程中,频繁并持续地发生液泡对细胞质组分的吞噬,导致大液泡的形成,其中有很多的酸性磷酸酶反应产物。大液泡的进一步扩大和继后的破裂,引起细胞的解体;②粗面内质网槽库彭大并对细胞质进行分隔与吞噬,在核周腔内出现膜束縛内含物;③质膜与细胞壁分离,二者之间有大量的小泡及酸性磷酸酶反应产物。最后珠心细胞的原生质强烈收缩,转化为无结构的电子致密的残迹。 相似文献
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用化工厂废水、皮革厂废水和该两厂的混合废水分别对水稻种子和蚕豆根尖进行处理,观察水稻种子发芽率及幼苗的生长状况,以及蚕豆根尖细胞的微核率、异形核率和有丝分裂指数等情况.结果表明：化工厂废水对水稻种子的发芽率及幼苗的生长均有极其显著的抑制作用;皮革厂废水及皮革厂与化工厂的混合废水对水稻的发芽率及幼苗生长的影响均不显著.工业废水能诱发蚕豆根尖细胞产生较高的微核率和异形核率.皮革厂废水61.20‰,两厂混合废水为34.34‰,化工厂废水为10.10‰;异形核率：化工厂废水为10%,两厂混合废水为5.16%皮革厂废水为1.38%;化工厂废水及两厂混合废水对蚕豆根尖细胞分裂具有明显的抑制和危害,皮革厂废水对蚕豆根尖细胞有丝分裂指数影响不显著.说明化工厂和皮革厂废水对农作物具有明显的细胞遗传毒性. 相似文献
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生菜遗传转化体系的建立及口蹄疫抗原决定簇融合基因的导入 总被引：1，自引：0，他引：1
以散叶生菜大速生为试材,以MS为基本培养基,采用不同激素配比,确定生菜高效诱芽培养基为MS 1.5 mg/L 6-BA 0.2mg/L IAA;抗生素敏感性试验表明,筛选培养基中适宜的潮霉素选择压为20 mg/L,抑菌剂羧苄青霉素的适宜质量浓度为300 mg/L;通过根癌农杆菌介导的叶盘法将携带O型和A型口蹄疫抗原决定簇融合基因O21-O14-A21-HBcAg转入大速生散叶生菜,PCR检测转化率达50%。 相似文献
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INTRODUCTIONNongreenplastidsofheterotrophictissuesarecarbohydrate importingorganellesand ,inthecaseofamyloplastsofstoragetissues,thesiteofstarchsynthesis.Investigationofwholetissuesfromavarietyofstarchsynthesizingcropplantsindicatedthathexoseunitswereimpo… 相似文献
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Motivation: It was found that high accuracy splicing-site recognition of rice (Oryza sativa L.) DNA sequence is especially difficult. We described a new method for the splicing-site recognition of rice DNA sequences. Method: Based on the intron in eukaryotic organisms conforming to the principle of GT-AG, we used support vector machines (SVM) to predict the splicing sites. By machine learning, we built a model and used it to test the effect of the test data set of true and pseudo splicing sites. Results: The prediction accuracy we obtained was 87.53% at the true 5' end splicing site and 87.37% at the true 3' end splicing sites. The results suggested that the SVM approach could achieve higher accuracy than the previous approaches. 相似文献
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水杨酸对NaCl胁迫下水稻(Oryza Saliva L.)幼苗生理活性的影响 总被引：1，自引：0，他引：1
用0．2％水杨酸处理1．2％NaCl胁迫下水稻种子，测定其以下几个生理指标，种子的发芽率，发芽势和幼苗中的酯酶，过氧化氢酶以及抗坏血酸的含量，实验结果显示：外源性水杨酸能够相对提高NaCl胁迫下水稻种子萌发后幼苗的过氧化物酶活性和抗坏血酸的含量，同时也能提高水稻种子的发芽率，发芽势，但对酯酶活性影响不大，研究表明水杨酸能提高水稻种子萌发后幼苗的抗盐性，并使水稻种子出苗整齐，一致。 相似文献