邻室传热相关问题的研究

由于供热计量收费,用户能够自主调节室温,用户之间室温会存在差异,这就导致存在邻室传热现象.所以确定房间设计热负荷时,就应该考虑邻室传热.为此,通过建立传热数学模型和运用概率统计方法,研究邻室传热的设计计算方法及相关因素,推导出邻室设计温差和邻室设计传热量的计算公式.结果表明,当用户采暖概率越小,邻室设计温差越大,并且概率小于0.7时,邻室设计温差小于5℃;分户墙保温越好,邻室设计温差越大,但对邻室设计温差影响不大;建筑设计热负荷越大,邻室设计温差越大.     

Osmotically stress-regulated the expression of glutathione peroxidase 3 in Arabidopsis

Gene expression of glutathione peroxidase 3 (ATGPX3) in response to osmotic stress was analyzed in Arabidopsis using ATGPX3 promoter-glucuronidase (GUS) transgenic plants. High levels of GUS ex- pression were detected under osmotic stress in ATGPX3 promoter-GUS transgenic plants. Compared with the wild type, the growth and development of ATGPX3 mutants (atgpx3-1) were more sensitive to mannitol. In addition, the expression of RD29A, ABI1, ABI2 and RbohD in atgpx3-1 was induced by ABA stress. These results suggest that ATGPX3 might be involved in the signal transduction of osmotic stress.     

Genetic diversity and construction of core collection in Chinese wheat genetic resources

Genetic diversity among 5029 accessions representing a proposed Chinese wheat core collection was analyzed using 78 pairs of fluorescent microsatellite （SSR） primers mapped to 21 chromosomes. A stepwise hierarchical sampling strategy with priority based on 4×10^5 SSR data-points was used to construct a core collection from the 23090 initial collections. The core collection consisted of 1160 accessions, including 762 landraces, 348 modern varieties and 50 introduced varieties. The core accounts for 23.1% of the 5029 candidate core accessions and 5% of the 23090 initial collections, but retains 94.9% of alleles from the candidate collections and captures 91.5% of the genetic variation in the initial collections. These data indicate that it is possible to maintain genetic diversity in a core collection while retaining fewer accessions than the accepted standard, i.e., 10% of the initial collections captured more than 70% of their genetic diversity. Estimated genetic representation of the core constructed by preferred sampling （91.5%） is much higher than that by random sampling （79.8%）. Both mean genetic richness and genetic diversity indices of the landraces were higher than those of the modern varieties in the core. Structure and principal coordinate analysis revealed that the landraces and the modern varieties were two relatively independent subpopulaUons. Strong genetic differentiation associated with ecological environments has occurred in the landraces, but was relatively weak in the modern culUvars. In addition, a mini-core collection was constructed, which consisted of 231 accessions with an estimated 70% representation of the genetic variation from the initial collections. The mini-core has been distributed to various research and breeding institutes for detailed phenotyping and breeding of genetic introgression lines.     

H-蛋白中Asp-68和Tyr-70定向突变对甘氨酸裂解酶系整体酶活的调控

还原甘氨酸途径被认为是最有前景的C1（one carbon）合成途径,其核心酶系是甘氨酸裂解酶系。在前期研究中,我们在甘氨酸裂解酶系H-蛋白“解开自保护”过程的研究中初步锁定了H-蛋白空腔内的潜在关键氨基酸残基为Ser-67、Asp-68和Tyr-70,并且证明Ser-67位点对甘氨酸酶系的整体酶活有重要影响。本文对H-蛋白的Asp-68和Tyr-70位点进行了侧链带正电突变（H-D68K、H-D68H、H-D68R和H-Y70K、H-Y70H、H-Y70R突变体）,以及侧链非极性突变（H-D68G、H-D68V、H-D68M、H-D68L和H-Y70G、H-Y70V、H-Y70M、H-Y70L突变体）,并测定了各突变体在甘氨酸裂解方向上的酶活。结果发现,Asp-68位带正电突变倾向降低甘氨酸酶系的整体酶活,Asp-68位非极性突变、Tyr-70位带正电突变及非极性突变在总体上倾向于维持或提升整体酶活。其中,相对野生型H-蛋白,H-D68R突变体的酶活下降了90.2%,H-Y70R、H-D68G和H-Y70L突变体的酶活分别提高了75.6%、53.6%和146%。硫辛酰胺与H-蛋白空腔内的氨基酸相互作用的分析结果表明,甘氨酸裂解酶系整体酶活的变化是由于H-蛋白的68和70位残基的突变阻碍或促进硫辛酰胺的释放。