Function analysis of a semi-dwarf sdg in rice with near isogenic lines

The physiological phenotype of the rice semi-dwarf mutant,sdg,was characterized in details using a pair of near isogenic .Neither gibberellin*deficient nor gibberellin-insensitive is characteristic of the sdgphenotype.Byanalyzing the secretion of aamylas and the promotion of stem growth caused by eogenous gibberellin(GA),the sdg plant was found to have decreased sensitivity to the GA at the seedling stage. The dwarfism stature of the sdg mutant can be attributed to the shortened internodes. Increase of the cell sults indicate the protein encded by the wild type gene of sdg may be a regulator for cell elogation.     

论成功的教育

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杨-桤混交林及其凋落物对土壤氮矿化的影响

【目的】研究含氮量中等的立地条件下杨-桤混交林相比于杨树纯林能否增加土壤养分,分析桤木是否为合适的固氮树种,探讨桤木与杨树营造混交林以缓解人工林连栽带来的土地肥力衰退问题。【方法】以苏北地区杨树人工纯林以及杨-桤(1∶1)混交林为研究对象,采用尼龙网袋法观察两种林分下凋落叶质量分解以及养分释放的过程,比较两种凋落物处理(去除凋落物与保留凋落物)对土壤全氮以及碱解氮含量的影响。采用树脂芯田间原位培养法,研究杨-桤混交林与杨树纯林两种林分在两种凋落物处理下,林地土壤氮年净矿化量的变化。【结果】营造杨-桤混交林显著提高了林地土壤全氮和碱解氮含量。杨树纯林凋落物分解时需从周围土壤中吸收更多氮素,且分解速率较慢。杨-桤混交林凋落物分解更快进入氮释放状态,因此去除凋落物后混交林土壤碱解氮显著减少。保留凋落物处理下,杨-桤混交林中每公顷土壤氮年净氨化量显著高于杨树纯林中的,去除凋落物后两者差异不显著。【结论】研究发现,桤木是杨树较合适的伴生树种,营造杨-桤混交林可以起到增加土壤全氮和碱解氮含量的作用,有助于缓解杨树纯林连栽带来的地力下降问题。混交林凋落物分解速率与氮素释放速率更快,有利于人工林生态系统氮循环。保留凋落物处理下,混交林中每公顷土壤氮年净氨化量显著高于杨树纯林的,而每公顷土壤氮年净硝化量没有显著差异,表明混交林凋落物分解释放的氮素主要促进土壤氨化过程,对土壤硝化过程影响较弱。     

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文章以举例的方式阐述一个人的成长经历,以此说明良好的家庭教育是非常重要的。     

Microdissection and amplification of the chromosome arm 5S in a rice telo-tetrasomic

The rice aneuploids with telochromosomes are ideal genetic stocks for chromosome arm identification and microdissection. A rice telo-tetrasomic line with two extra short arms of chromosome 5 (5S) was used in the present study. The amrs of 5S were microdissected from the prometaphase cells in mitosis and amplified with linker adaptor PCR (LA-PCR). The amplified fmgments, ranging from 200–3000 bp, were confirmed to be from the rice chromosome arm 5S by the rice STS and miamatellite markers.     

Optical mapping of a rice BAC clone using restriction endonuclease and imaging with fluorescent microscopy at single molecule level

A method of constructing restriction map by optical mapping and single molecule fluorescent microscopy is described. DNA molecules were aligned and adsorbed on a glass coverslip surface by a modified “molecular combing” technique, and then the surface-immobilized DNAs were cleaved in situ with a restriction endonuclease. Individual DNA molecules digested by the endonuclease EcoRⅠ were observable with fluorescent microscopy. Using optical mapping, a physical map of a rice bacterial artificial chromosome clone was constructed. This method will facilitate genomic mapping and tracing the dynamic process in real time at a single molecule level with fluorescence microscopy.     

Molecular tagging of a genic male-sterile gene in rice

The sterility of Pingxiang male-sterile rice (Pms), possibly derided from a spontaneous mutation in Pingxiang fertile rice (Pmf), was previously reported to be controlled by a single dominant nuclear gene. It can be restored to fertility either by a dominant epistatic gene or by higher temperature treatment at the early stage of inflorescence development. In order to tag the genic male-sterile gene, Pms, Pmf and Ce 64, a cytoplasmic male-sterile restoring line without the epistatic gene for Pms, were used to construct mapping populations. Two segregation populations, “(Pms/Ce 64) F1s (sterile plant)//Pmf ” F1 and “Pms//(Pmf/Ce 64) F1” F1, were simultaneously developed. Subsequently, the genic male- sterile gene was mapped between a simple sequence length polymorphism marker, RM228, and a restriction fragment length polymorphism marker, G2155, with distances of 14.9 and 2.6 cM, respectively. The tagged dominant genic male-sterile gene is temporarily designated Ms-p.     

Efficient selection of homozygous lines of hybrid rice restorer with the transgeneXa21 using test cross and PCR

The homozygous restorer lines with a single copy of the transgene Xa21 have been obtained from the progenies of transgenic Minghui63 and Yanhui559 plants through PCR marker-assisted selection and test cross. These homozygous transgenic restorer lines can be used to breed hybrid rice with high resistance to bacterial leaf blight.     

Identification of quantitative trait loci affecting tolerance to low phosphorus in rice (Oryza Sativa L.)

Phosphorus (P)-deficiency in rice (Oryza. Sativa. L) may cause yield reductions. This research has been conducted to map quantitative trait loci (QTLs) for tolerance to low phosphorus stress in a doubled haploid (DH) population. By using the linkage map of this population, the QTLs for relative dry weight, relative P content and relative P utilization efficiency have been located. The results indicate that one RFLP marker located on chromosome 6 is closely associated with relative root dry weight, relative shoot dry weight and relative total dry weight, which explain 24.9%, 20.5% and 25.2% of the total phenotypic variations, respectively. Two QTLs affect relative P uptake content, which account for 20.7% of the total phenotypic variations. One micro-effect QTL has been found to be associated with relative P utilization efficiency. It is suggested that the P uptake efficiency is more associated with P efficiency. Among the secondary physiological indices of P uptake efficiency, the root dry weight is more important than others.