干旱胁迫下不同品种杨树矿质离子含量变化

【目的】了解杨树在干旱胁迫下矿质离子分布及其动态变化。【方法】以吴屯杨、新疆杨和荷兰杨为实验材料,在中度和重度干旱条件下测定了根、茎、叶和质外体的K^+、Ca^2+、Na^+和Mg^2+等4种离子含量的变化。【结果】干旱胁迫使K^+、Ca^2+和Na^+离子含量上升,Mg^2+含量下降,其中K^+和Ca^2+含量自胁迫开始明显升高,Na^+含量则在中度胁迫之后明显增加。离子在各器官分布情况为:K^+主要分布于杨树的叶片,Ca^2+、Na^+和Mg^2+主要分布于杨树根部,且离子分布存在品种间差异,荷兰杨和新疆杨中K^+分布为:叶>根>茎,而吴屯杨体内K^+分布则为:叶>茎>根;3种杨树中Ca^2+分布均为:根>叶>茎;吴屯杨和荷兰杨中Na^+分布为:根>茎>叶,新疆杨则为:根>叶>茎;在Mg^2+的分布上吴屯杨和新疆杨较为类似即:根>叶>茎,而荷兰杨为叶>根>茎。【结论】干旱胁迫下杨树首选吸收的离子是K^+和Ca^2+,K^+主要分布在杨树的叶片中,其次是根部,Ca^2+主要分布在杨树的根部。重度干旱胁迫下,杨树开始吸收Na^+,储存在杨树的根部。不同品种杨树之间离子的分布和吸收都存在品种差异。质外体作为离子的运输通道,在各干旱条件下运输4种矿质离子至杨树的其他部位,Mg^2+存在滞留在质外体中的情况。本研究可为植物在干旱胁迫下矿质离子吸收和分布的研究提供理论依据。     

Development of a linear mixed-effects individual-tree basal area increment model for masson pine in Hunan Province,South-central China

ABSTRACT

An individual-tree basal area increment model was developed for masson pine based on 26276 observations of 13,138 trees in 987 sample plots from the 7th (2004), 8th (2009), and 9th (2014) Chinese National Forest Inventory in Hunan Province, South-central China. The model was built using a linear mixed-effects approach with sample plots included as random effects since the data have a hierarchical stochastic structure and biased estimates of the standard error of parameter estimates could be a consequence of applying ordinary least square (OLS) for regression. In addition, within-plot heteroscedasticity and autocorrelation were also considered. The final mixed-effects model was determined according to the Akaike information criterion (AIC), Bayesian information criterion (BIC), log-likelihood (Loglik), and the likelihoodratio test (LRT). The results revealed that initial diameter (DBH), the sum of the basal area (m²/ha) in trees with DBHs larger than the DBH of the subject tree (BAL), number of trees per hectare (NT), and elevation (EL) had a significant impact on individual-tree basal area increment. The mixed-effects model performed much better than the basic model produced using OLS. Additionally, the variance structure of the model errors was successfully modeled using the power function. However, the autocorrelation structures were not defined because there was no autocorrelation amongst the data. It is believed that the final model will contribute to the scientific management of the masson pine.     

大型薄壳制件真空辅助树脂传递模塑工艺充模方案仿真分析及优化

针对大型树脂基复合材料制件不适于用实验试错法进行充模方案设计的问题,在分析树脂流动规律的基础上将大型薄壳件的求解区域分解,仿真分析了不同充模方案下树脂在纤维中的流动行为和模腔内压力变化,提出在制件填充面积等分处设置流道的方法,选择和优化大型薄壳制件的充模方案。结果表明:①对于不便进行实验试错法进行真空辅助树脂传递模塑(VARTM)工艺充模方案设计的大型薄壳制件,可以采用数值模拟的方式,以达西定律、能量守恒定律等为计算依据,求解压力场和速度场,对比不同仿真方案的充模时间等数据合理安排注胶方式方法,指导VARTM工艺制备大型复合材料制件合理安排注胶方式,提高生产率、减少因树脂浸润不均匀产生的缺陷。②对于大型薄壳类制件,忽略厚度方向尺寸,影响充模时间的主要因素为流道长度和树脂流动距离。选取尽可能长的注胶流道,合理设置流道位置以减少树脂流动的距离;长流道可以增加树脂瞬时注入量、提高较长时间的压力差;而树脂流程越长,树脂前锋处压力损失越大,流速越慢。③试验提出了制件填充面积等分处设置流道的方法。将大型薄壳工艺制件充模面积等分,注胶流道布置在垂直于制件长度方向的面积等分线上,可缩短充模时间并减少制件两端的树脂富集现象。对于较狭长部分可再次进行面积等分设置流道,以免造成树脂流程过长压力流失过多;而对于较宽阔部分不宜设置过多流道以免树脂前锋稳定前互相接触造成制件充模不均匀。     

Genetic diversity and structure of Northern Sheatfish (Silurus soldatovi) assessed by newly developed and cross‐species microsatellites

Twenty‐five polymorphic microsatellite markers, including 13 newly isolated markers and 12 existing cross‐species markers, were used to assess the genetic variation of 141 individuals from three cultured stocks of northern sheatfish, Silurus soldatovi, in China. Samples were collected from Heilongjiang (H), Tongerpu (T) and Liaoning (L). Allelic richness, expected and observed heterozygosity among 25 loci were calculated, and the mean A_e, H_o and H_e were estimated in three stocks. In low polymorphic locus HLJcf19 and HLJcf38, most individuals in all three stocks were homozygous and had only one same allele, while only few heterozygous individuals had the other allele in one certain stock. And all the three stocks showed excess of heterozygotes, because of significant negative F_IS values. Genetic distance, UPGMA dendrogram, as well as structure analysis, all indicated that Stock H and L were closer among three stocks. The results revealed that though all stocks had no reduction in recent time, their effective population size were significantly lower to the ideal value.     

利用因子分析综合评价9个西藏农家青稞品种的品质

随着青稞加工产业的发展,筛选西藏优质种质资源将有助于培育适宜加工的青稞品种。选取9个西藏农家青稞品种,以藏青25为对照,通过测定31项化学特性指标,建立品质综合评价体系。结果表明:经因子分析提取出6个特征值大于1的主成分,累积方差贡献率为94.65%,其中第1主成分的贡献率为49.81%,主要包含蛋白质及苏氨酸（THR）、脯氨酸（PRO）、丙氨酸（ALA）、缬氨酸（VAC）、亮氨酸（LEU）、苯丙氨酸（PHE）、组氨酸（HIS）、赖氨酸（LYS）、清蛋白、总氨基酸含量等指标;第2主成分的贡献率为13.85%,其中粗脂肪、直链淀粉、膳食纤维、γ-V_E、磷含量具有较大的载荷值。根据建立的品质综合评价模型,优良度得分排序为:藏青25>青21>隆子黑>拉萨长黑>联嘎木>拉萨短白>彭乃嘎布>江热俄久>直孔嘎夏>联木白稞。     

水产养殖车间LED光环境设计研究

为在水产养殖车间的光照设计中选择最优的光色、光强与光周期参数及合适的灯具,提高水产养殖生产效率,根据水产动物在进化过程中形成的独特视觉生理结构及对光反应敏感的适应性特点,进行了水产养殖车间LED人工光照设计方案研究,针对目前水产养殖产业在光照上经常出现的模糊问题,提出了在设计LED人工光照方案时应遵循的一般原则,并在此基础上对如何降低养殖车间光照成本给出了合理的建议。     

银杏GbERF1转录因子基因的克隆及亚细胞定位分析

ERF是植物中一类重要的转录因子,广泛参与植物对生物和非生物胁迫的响应。以3年生银杏苗为试材,采用RT-PCR与RACE-PCR方法,研究了银杏ERF基因序列,以期深入了解银杏药用成分合成代谢的分子机理。结果表明:GbERF1含有长度为1 314bp的完整开放阅读框,编码437个氨基酸。蛋白序列分析显示,GbERF1蛋白含有2段ERF家族的特殊位点。GbERF1蛋白序列与北美云杉(ADE75663.1)序列的相似性为97%。系统进化树分析,GbERF1与北美云杉、狭叶羽扇豆的序列可划归为同一分支。实时荧光定量PCR结果显示,GbERF1主要在银杏根和叶中表达,逆境胁迫处理后显示,该基因在乙烯、紫外诱导处理下,表达量大幅度提升,随后下降,但仍高于对照组,干旱诱导处理下表达量先升高后降低,矮壮素(CCC)诱导下表达量变化不太明显。烟草叶片下表皮细胞亚细胞定位结果表明GbERF1定位于细胞核。     

黑沙蒿根系抗拉特性及其与化学成分的关联性

[目的] 探讨根系抗拉特性与主要化学成分含量的关联性，以期充实根系固土力学特性研究以及提供矿区生态恢复和植物保护的理论支持。[方法] 以神东矿区广泛分布的多年生灌木黑沙蒿（Artemisia ordosica）为研究对象，利用TY8000伺服式强力机，研究1~4 mm径级直根段、含侧根分支处根段抗拉材料的力学特性并测定各径级的纤维素、半纤维素和木质素，研究根系材料力学及其与化学成分的关联性。[结果] ①随着根系直径增加，黑沙蒿直根段、含侧根分支处根段抗拉力增加，而抗拉强度和杨氏模量减小，且抗拉力、抗拉强度和杨氏模量都与根系直径呈幂函数关系。②直根段、含侧根分支处根段化学成分含量差异显著（p<0.05），平均化学成分含量为：半纤维素（31.69%，32.18%） > 木质素（28.42%，25.30%） > 纤维素（15.50%，15.35%）。③随着根系直径增加，直根段纤维素含量减小，半纤维素和木质素含量增加，而含侧根分支处根段纤维素含量减小，半纤维素和木质素含量无变化。④直根段抗拉强度、杨氏模量与纤维素极显著正相关（p<0.01），与半纤维素、木质素极显著负相关（p<0.01）。含侧根分支处根段抗拉强度、杨氏模量与纤维素极显著正相关（p<0.01），与半纤维素、木质素无相关性。[结论] 黑沙蒿根系抗拉特性与化学成分表现出一定的相关性，且纤维素是影响灌木根系材料力学特性的主要化学组分。     

干制羊肉基因组DNA不同提取方法的比较

为了研究干制加工羊肉基因组DNA的最佳提取方法,本试验采用传统酚-氯仿法、磁珠法、改良CTAB法、离心柱法分别提取干制处理后的羊肉基因组DNA,并对4种方法提取的羊肉基因组DNA浓度、纯度、完整性以及提取所需时间、PCR扩增效果等进行比较。结果表明,采用磁珠法提取DNA的效果更好,DNA浓度为118.87 ng·μL^-1,A₂₆₀/A₂₈₀值为1.89,而且此方法具有提取时间短、效率高、污染小等特点。本研究结果为干制加工羊肉基因组DNA的大批量提取和检测提供了参考依据。     

A new species of Malus in China,Malus shizongensis Liu sp. nov

Based on morphological, molecular biological, and molecular systematic studies, we describe here a new species of Malus from Yunnan, China. We compared the morphology of this new species, Malus shizongensis Liu sp. nov, with three Malus species, including M. hupehensis, M. baccata, and M. micromalus. Although the appearance of M. shizongensis was similar to these three species, it differed in height, branch color, branch hair, and flower color. To better identify the taxonomy of this new species, genome of M. shizongensis and that of seven Malus species, including M. prunifolia, M. sylvestris, M. sieversii, M. hupehensis, M. baccata, M. robusta, and M. micromalus were analyzed. A phylogenetic tree based on genome analysis indicated that M. shizongensis was close to M. hupehensis. Furthermore, M. shizongensis had its species-specific SNPs, and the number of species-specific SNPs was similar to that of three close species(M. hupehensis, M. baccata, and M. micromalus). Based on the above information, we named this new species as M. shizongensis Liu sp. nov.