Phenological development of East African highland banana involves trade-offs between physiological age and chronological age

The phenology of East African highland banana (Musa acuminata AAA-EA, hereafter referred to as ‘highland banana’) is poorly understood. We tested three hypotheses: (1) the physiological age at flowering is independent of site effects, (2) there is no difference in threshold size at flowering between sites with different growth potential, and (3) morphological and physiological components of highland banana relative growth rate (RGR) contribute equally to mitigate growth reduction in response to limiting supply of water, K or N. The physiological age of highland banana plants from field trials at Kawanda (central Uganda) and Ntungamo (south-western Uganda) was computed from daily temperature records. Growth analysis was conducted using RGR, net assimilation rate (NAR), specific leaf area (SLA) and leaf mass ratio (LMR) estimated from allometry. Growth response coefficients were used for quantifying the relative contribution of NAR, SLA and LMR to RGR. Physiological age at flowering was delayed by 739 °C d at Kawanda compared with that at Ntungamo whose chronological age at flowering was in turn 51 d older. At both sites a threshold total dry mass of 1.5 kg per plant was required for flowering. Faster absolute growth rate and NAR fostered by wet conditions, K input and cooler temperatures enabled plants at Ntungamo to attain the threshold total dry mass sooner than those at Kawanda, hence the phenotypic plasticity in age at flowering. Net assimilation rate contributed at least 90% to RGR increase due to wet conditions at both sites. The contribution of NAR to RGR increase in response to K at Kawanda reduced to 38% while that for SLA increased to 49%. Net assimilation rate contributes more to highland banana RGR modulation than SLA except when warmer conditions reduce NAR. Differences in crop growth rate cause phenotypic plasticity in highland banana rate of phenological development.     

表型可塑性对木本植物树冠结构与发育的影响

作为一组固生生物 ,树木具备一种独特的生存能力来适应在漫长生长过程中发生的环境变化。正是因为这样的原因 ,树木的许多生物学特性 ,如分枝习性与树冠结构 ,代表了树木的生长“蓝图”或基因型与其生长环境及历史的互作关系。遗传因子通过突变 ,染色体重组、基因重复 ,易位与互换等过程形成树木发育成固定的结构。早期形态学家已认识到 ,树木存着大量的形态与发育方面的重复 ,利用这些重复的分化 ,许多热带树种可以被划分成少数几组形态。类似的工作已用在温带树木的结构分析上。但是 ,尽管发展这样的一个分类机制是很容易的 ,然而实际的应用却非常困难 ,这是因为在相同的树木类别内 ,甚至在相同树种内 ,存在着巨大的表型分化。不同的环境或发育过程会使具有相同基因型的树木产生不同的结构 ,由此可见其影响和遗传影响同样复杂环境对树木结构的影响称为表型可塑性。通过缓解自然选择的效应 ,表型可塑性对提高植物适应能力具有重要作用。如果表型可塑性存在遗传变异 ,那么 ,具有不同可塑性的群体会产生进化。表型可塑性亦可用于分析由环境引起的性状相关 ,例如环境能导致性状相关在方向与大小上的变化。基因型与环境互作的结果导致有机体的发育以外遗传的系统的改变 ,产生所谓的异时性生长 (heterochron     

一株地衣芽孢杆菌的性质研究及发酵培养基优化

[目的]研究实验室自分离的地衣芽孢杆菌KL6作为微生物饲料添加剂的可行性,并对其发酵培养基进行优化,确定最佳培养条件,为工业化发酵提供依据。[方法]运用表型试验对其进行生理生化评价及产酶评价;运用4因素3水平正交试验和单因素试验对其培养基进行改进,并对其发酵条件进行优化。[结果]地衣芽孢杆菌KL6的D-葡萄糖产酸试验、硝酸盐还原试验、淀粉水解试验等均呈阳性;4种因素对活菌数影响的显著性次序为:MnSO4>NaCl>酵母粉>蛋白胨,对芽孢数影响的显著性次序为:MnSO4>蛋白胨>酵罐放大培养,最佳放罐时间应在14～16 h,获得的菌体数量约101.63×109个/ml,芽孢率为97.11%。[结论]体外评价试验表明,地衣芽孢杆菌KL6具有作为微生物饲料添加剂的潜力;发酵培养基及条件优化试验表明,地衣芽孢杆菌KL6能够适于高密度液体发酵。该试验为以KL6为基础的微生物饲料添加剂的开发和大规模发酵培养提供了理论依据。     

Wild Cherry (Prunus avium L.) for Timber Production: Consequences for Early Growth from Selection of Open-pollinated Single-tree Progenies in Sweden

Prunus avium L. is a fast-growing hardwood tree species that has demonstrated good production on both well-drained forest soils and farm land in southern Sweden. Growth rate and breeding value were tested in 101 open-pollinated single-tree progenies of Swedish origin and five German seed sources. After eight growing seasons and two selective thinnings the mean tree height reached 4.7 m. The mean tree height of the progenies varied between 3.3 and 6.1 m. A total rotation period of 50-60 yrs and a dominant height of 20-22 m can be expected. The results indicated great phenotypic variation within progenies and good possibilities for improving production and stem quality by early selective thinning. In terms of height growth and stem straightness the best Swedish progenies were as good as the tested German seed sources.     

Estimation of genetic parameters of conformation traits in Iranian Thoroughbred horses

The aim of this study was to estimate the genetic parameters of conformation traits in Iranian Thoroughbred race horses. The data set included the conformation records of 607 Thoroughbred horses. In this study, 10 conformation traits were recorded. The effect of sex was significant for length of back line (P < 0.05), withers height (P < 0.05), circumference of front cannon (P < 0.001), and circumference of hind cannon (P < 0.001). The effect of age was significant for all traits (P < 0.01). The genetic parameters were estimated by the restricted maximum likelihood (REML) method using DFREML program. The heritability estimates were for head length 0.39, length of back line 0.41, length of shoulder 0.24, heart girth 0.49, chest width 0.22, withers height 0.38, front cannon height 0.27, circumference of front cannon 0.30, hind cannon height 0.29 and circumference of hind cannon 0.34. The estimates of genetic correlation ranged from 0.18 to 0.96 and those of phenotypic correlation varied from 0.16 to 0.83.     

Role of nucleolin in Ang II-induced phenotypic transformation of vascular smooth muscle cells

AIM: To investigate the effect of nucleolin on angiotensin II (Ang II)-induced phenotypic transformation of vascular smooth muscle cells (VSMCs). METHODS: Ang II was used to induce the phenotypic transformation of VSMCs. The spatial and temporal expression patterns of nucleolin, and the effects of Ang II on the expression of VSMC phenotypic transformation markers α-smooth muscle actin (α-SMA), calponin, smooth muscle protein 22 α (SM22α) and osteopontin (OPN) were investigated. The techniques of gene over-expression and RNA interference were used to assess the effect of nucleolin on the expression of Ang II-mediated VSMC phenotypic transformation markers. RESULTS: The expression of α-SMA, SM22α and calponin at the mRNA and protein levels was gradually decreased by Ang II stimulation, while the expression of OPN at mRNA and protein levels was gradually increased. The expression of nucleolin was gradually up-regulated in the VSMCs treated with Ang II at different concentrations for various duration (P<0.05). Ang II induced nucleolin translocation from the nucleus to cytoplasm. Over-expression of nucleolin promoted the VSMC phenotypic transformation induced by Ang II. Down-regulation of nucleolin suppressed the promotion of phenotypic transformation. CONCLUSION: Nucleolin promotes Ang II-induced phenotypic transformation of VSMCs, and its mechanism may be related to its function of cytoplasmic translocation.     

表型轮回选择和混合选择改良小麦群体效应的研究

在吴兆苏等(1984)创建的小麦基础群体中,采用不同的选择方案,对不育株和可育株分别进行两轮选择。结果表明两轮选择显著地降低了可育株和不育株群体的株高。可育株群体株高的下降速率大于不育株群体。单株产量和单株穗数没有得到显著的改良。相关性状穗长、千粒重等出现负向间接选择效应。轮回选择通过选株间的互交,维持了不     

日本野生大豆中的四个种子蛋白和两个性状的多态及地理分布

本文电泳调查了日本1767野生大豆个体的种子胰蛋白酶抑制剂类型及频率分布。日本野生大豆存在两类型,即Tia和Tib,频率分别为94.5％和5.5％。从纬度上看,34°～38°带比其它纬度带有较高的Tib频率。本调查看到约1％的材料是Tia/Tib杂和体。 首次观察了3种蛋白的变异性。这些蛋白具有明显的多态性及地理分布差异。K1有3个形态:缺失体,快带和慢带;K2有两种形态:快带和慢带;B有两种形态:快带和慢带。本文提出这3种蛋白可以做为“等位酶”,用于野生大豆地理遗传分化的研究。 日本野生大豆的种皮过氧化物酶活性表型频率略高于中国,荧光型频率远高于中国。初步讨论了日本天然野生大豆群体的遗传变异,似乎由低纬度到高纬度地理变异的程度增大。     

应用大豆表型设计育种技术选育大豆品种齐黄34

大豆产量由群体结构和个体生产力共同决定。其中,群体结构由个体的结荚习性、株高、主茎节数、分枝数、叶柄和叶片等株型性状决定;个体生产力由单株有效荚数、每荚粒数和粒重等性状决定,这些性状都具有特定的遗传和变异规律。表型设计育种是根据农作物表型性状的遗传和变异规律,设计出理想的表型性状值并培育出理想品种的育种技术。大豆品种齐黄34就是根据生态环境、生产条件和市场需求,采用表型设计育种技术选育成的高产大豆品种,具有株型紧凑、个体生产潜力大等特点。     

中国白菜型油菜种质表型多样性分析

以保存于油料作物中期库中的1 962份白菜型油菜种质为基础材料,按照地理位置、表型性状分组并按比例取样,选择具有代表性的244份地方品种,对其13个表型性状进行分析。结果显示,来源于山西省的冬油菜生育日数较长,来源于青海、内蒙古、甘肃等省的春油菜生育期较短;来源于四川省的半冬型油菜株高较高;来源于云南、四川省的半冬型油菜全株角果数较多;来源于西藏的材料千粒重较大。多样性指数结果表明,我国白菜型油菜地方种具有丰富的形态多样性,平均多样性指数为1.709, 高于国外材料(1.250);就不同生态类型而言,半冬型油菜多样性指数最高,其次为春油菜,冬油菜最低。聚类分析结果显示,在相似系数为0.204时,244份白菜型油菜地方种质划分为四簇,每簇包含的种质数分别为117、38、34和55;簇Ⅰ以半冬型油菜为主,簇Ⅱ、Ⅲ以春油菜为主,簇Ⅳ以冬油菜为主。主成分分析结果显示,白菜型油菜分为春油菜、半冬型油菜与冬油菜三个明显的基因库,其结论与聚类分析结果一致。