Stand structure of an uneven-aged fir–beech forest with an irregular diameter structure: modeling the development of the Belevine forest, Croatia

This study focuses on the problem of irregular diameter structure in a silver fir–beech selection (plenter) forest with a “surplus” of large diameter trees and a lack of natural regeneration and small diameter trees. We sampled 274 plots (900 m² each) in the Belevine research site (266.24 ha) in the mountain region Gorski Kotar (Croatia), where diameter (dbh) distribution, diameter increment, and natural regeneration were analyzed in detail. A low density of natural regeneration, weak annual recruitment of small (10 cm dbh) diameter trees (only five trees per hectare), delayed diameter growth of trees, and a low annual rate of trees reaching the next dbh class were attributed to the current irregular dbh structure. The stand development prediction for the next 50 years is based on a simulation model, which considers the current diameter structure, increment, recruitment, and future cutting regime. Intensive cutting in the first of five 10-year cutting cycles (intensity higher of 25%) is needed to initiate natural regeneration and to accelerate growth of young silver fir trees. In the next 50 years, the irregular diameter structure will be gradually improved.     

Variations in soil chemical properties and microbial biomass in artificial gaps in silver fir stands

Changes in soil chemical and microbiological parameters in small (185 m²) and medium (410 m²) gaps, created in mature silver fir (Abies alba Mill) stands (mean height 30 m) in the Calabrian Apennines (Southern Italy), were studied over 2 years. Medium gaps had high soil temperature and photosynthetically active radiation (PAR) transmittance and low soil moisture. Within small gaps we detected a greater amount of organic matter, with respect to under canopy cover sites and medium gaps. Moreover, a different trend of the organic matter between small and medium gaps was observed. In the medium gaps, with respect to under canopy cover sites and small gaps, we found a relatively low content of organic matter, associated to a lower amount of humic acid, which suggested that the organic substrate undergoes a mineralization rather than a humification process. An opposite trend was observed in small gaps, where the increase of organic matter content, associated to an increase of humic acid and microbial biomass, suggested a better humification process. Moreover, in small gaps the highest level of urease and the greatest fluorescein diacetate (FDA) hydrolysis were observed. The different trend of organic matter observed in small and medium gaps may be related to changes in the environmental conditions. PAR transmittance, significantly higher in medium gaps, contributed to increase soil temperature and decrease soil moisture, affecting soil microbial populations and organic matter trend. These results suggest that the creation of small gaps represents the silvicultural practice with minor environmental impact.     

Field performance of silver-birch planting-stock grown at different spacing and in containers of different volume

Silver birch seedlings were grown in two types of trays differing incell volume. For each kind of tray, three different spacings were achieved bygrowing seedlings in all, half or one quarter of the cells. The planting-stockso produced was out-planted at two forest sites and growth followed for fiveyears. Container size had a large effect on seedling morphology and on fieldperformance. Density also had a large effect on seedling morphology, but littleinfluence on performance. The tightest relationship of field performance was tothe mean dry weight of the stems of the planting stock (R² = 0.94).Mean height and sturdiness index, defined as diameter ÷height, were not correlated with performance. Of the non-destructivemeasurements, mean root-collar diameter was the most closely correlated withperformance.     

金花茶松散型愈伤组织诱导与悬浮细胞系建立

采用组织培养及显微观察技术,以金花茶植株茎段、叶片、花药及离体培养的金花茶体细胞胚为试验材料,对松散型愈伤组织的获得及悬浮细胞系的建立进行了研究。结果表明:在黑暗条件下,以金花茶体细胞胚切块为外植体,在MS+KT 0.5 mg/L+NAA 8.0 mg/L+硝酸银5mg/L+蔗糖30 g/L培养基上诱导出愈伤组织后,将其转接到该诱导培养基上连续培养3个月,最后从培养物中挑选状态良好的松散型愈伤组织在分别含有肌醇与硝酸银的2种培养基上交替培养,可以获得金花茶松散型愈伤组织;方差分析表明:蔗糖添加量、肌醇添加量及硝酸银添加量均对金花茶悬浮培养液细胞密度有显著影响且后两者分别与光照条件存在相互作用;将松散型愈伤组织在分别添加100 mg/L肌醇与2.5 mg/L硝酸银的液体增殖培养基上交替培养,可以建立并保持金花茶悬浮细胞系。该研究结果可为金花茶大规模细胞培养提供科学依据。     

南瓜银叶突变体48a的表型特征及其遗传学分析

南瓜银叶突变体48a是在嫩食型中国南瓜中分离筛选到的稳定遗传自交系,银色叶不仅可以作为标记性状应用到育种中,还可为南瓜抗虫、抗病、耐寒等一系列研究提供重要的材料基础。笔者对银叶突变体的表型特征及叶片的解剖结构进行鉴定分析,发现植株整体长势、熟性与野生型无明显差异;成熟叶片正面全部呈银灰色,叶绿素含量明显降低,叶片上表皮细胞与栅栏细胞间明显剥离,存在明显的空隙。利用突变体48a和野生型49a南瓜自交系构建的六世代遗传群体,调查发现F2的绿叶与银叶符合3∶1的分离比,回交群体BC1P1分离比符合1∶1,表明南瓜银色叶性状由单隐性基因控制。     

Impact of Wall Material on the Physiochemical Properties and Oxidative Stability of Microencapsulated Spray Dried Silver Carp Oil

This study aimed to microencapsulate silver carp oil by spray drying with different combinations of wall materials (gum Arabic, modified starch Hi-cap, maltodextrin, and inulin) and evaluate the effects of these combinations on the physiochemical and oxidative stability of the microcapsules. Feed emulsions were also investigated prior to spray drying. Modified starch-based microcapsules had higher encapsulation efficiency (91.22-92.78%) and yield (87.41-92.15%), excellent solubility (91.85-93.67%), good particle size (301.20-407.73 d.nm), color, and powder morphology. The presence of inulin reduced agglomeration in powders. All the powders exhibited good protection against lipid oxidation during 2 months of storage, whereas the modified starch and inulin combination provided the best stability.     

仁用杏微卫星非变性聚丙烯酰胺凝胶电泳体系的优化

[目的]优化仁用杏微卫星非变性聚丙烯酰胺凝胶电泳体系。[方法]以25份仁用杏和3份食用杏为材料,利用微卫星标记结合非变性聚丙烯酰胺凝胶电泳技术筛选出多态性高、可重复的SSR位点。并比较不同因子对电泳体系的影响,探索仁用杏微卫星非变性聚丙烯酰胺凝胶电泳的优化体系。[结果]仁用杏微卫星非变性聚丙烯酰胺凝胶电泳的优化体系为：聚丙烯酰胺凝胶的浓度为6%,丙烯酰胺与甲叉双丙烯酰胺的比例为29∶1,1000V下电泳2～3h,0.1%AgNO3染色15min后显影。[结论]该优化体系为仁用杏资源微卫星标记遗传分析奠定了技术基础。     

芹菜鲢鱼蛋白复合饮料的工艺研究

[目的]确定芹菜鲢鱼蛋白复合饮料的最佳复配条件。[方法]通过采用中性蛋白酶和木瓜蛋白酶混合酶解鲢鱼蛋白,制取鲢鱼蛋白水解液,再经过脱腥、脱色、浓缩后,与芹菜汁复配成具有降血压、降血脂等功能的保健型复合饮料,研究鲢鱼蛋白水解液添加量、芹菜汁添加量、糖添加量、柠檬酸添加量对饮料感官性状的影响,通过正交试验确定该饮料的最佳复配条件。[结果]由正交试验获得饮料的最佳复配条件为：每100 ml饮料中鲢鱼蛋白水解浓缩液添加量20 ml,芹菜汁添加量12 ml,白砂糖添加量7 g,柠檬酸添加量0.20 g。此时,该饮料色泽成浅绿色,半透明,风味口感最好,组织状态均一稳定,无悬浮物或沉淀。[结论]该研究为鱼肉蛋白的深加工与利用提供了科学依据。     

中国鲳成鱼和幼鱼肌肉生化成分的比较分析

利用常规肌肉生化成分测试方法测定了中国鲳成鱼和幼鱼肌肉的一般生化成分、氨基酸和脂肪酸含量。结果表明,中国鲳成鱼和幼鱼肌肉中的一般生化成分均具有显著性差异。除水分外,成鱼肌肉的粗灰分、粗蛋白和粗脂肪含量均显著性高于幼鱼(P<0.05)。中国鲳成鱼和幼鱼肌肉中含有包括色氨酸和牛磺酸在内的18种氨基酸,总量分别为78.68%和72.92%(质量分数,干样),其中包括人体必需氨基酸8种,总量分别为33.26%和31.05%,分别占氨基酸总量的42.28%和42.58%;中国鲳成鱼和幼鱼的必需氨基酸组成比例基本符合FAO/WHO的标准。中国鲳成鱼和幼鱼的限制性氨基酸均为色氨酸和蛋氨酸+胱氨酸,必需氨基酸指数分别为62.16和77.68,4种鲜味氨基酸含量分别为28%和26.44%(干样)。中国鲳成鱼和幼鱼肌肉中脂肪酸种类丰富,成鱼肌肉含有饱和脂肪酸(SFA)7种,单不饱和脂肪酸(MUFA)5种,多不饱和脂肪酸(PUFA)8种;而幼鱼肌肉中SFA8种,MUFA6种,PUFA7种。中国鲳成鱼和幼鱼肌肉中EPA含量较低,分别占肌肉脂肪酸的2.49%和4.86%;而DHA较高,分别占肌肉脂肪酸的10.26%和16.23%。中国鲳成鱼和幼鱼必需氨基酸的A/E值较为接近,大小顺序均为:赖氨酸>亮氨酸>精氨酸>缬氨酸>异亮氨酸>苏氨酸>苯丙氨酸>蛋氨酸>组氨酸>色氨酸。     

卡拉胶和超高压对鱼糜凝胶性质的影响

以白鲢鱼糜为研究对象,将卡拉胶添加其中,经超高压处理后,再经二段加热处理形成鱼糜凝胶,测定其凝胶强度、白度值、pH值,研究压力、保压时间和卡拉胶质量分数对白鲢鱼糜凝胶性质的影响.单因素实验表明,当压力大于300 MPa时凝胶强度显著下降;保压时间大于10 min,卡拉胶质量分数大于0.8％时凝胶强度变化不显著.通过正交实验确定了优化工艺条件为:压力300 MPa、保压时间10 min、卡拉胶质量分数0.8％.各因素对白鲢鱼糜凝胶强度影响程度由大至小依次为压力、保压时间、卡拉胶质量分数.研究结果表明,超高压处理协同添加卡拉胶能够促进白鲢鱼糜形成良好的凝胶.