Effects of soil water availability on development of suberin lamellae in the endodermis and exodermis and on cortical cell wall thickening in red bayberry (Myrica rubra Sieb. et Zucc.) tree roots

The effects of soil water availability on suberin lamellae formation in the endodermis and exodermis and the occurrence of cell wall thickening in the cortex in red bayberry (Myrica rubra Sieb. et Zucc.) tree roots were examined during tissue aging. For several months, red bayberry trees were grown in small baskets under dry, normal, and waterlogged soil water conditions. Transverse sections of roots from 5 mm from the tip to the basal portion were stained with several staining solutions and the cell structure was observed. Root anatomical development was significantly changed by soil water conditions. The suberin lamellae in the endodermis formed later in plants grown under dry conditions than in those grown under waterlogged conditions. Cell wall thickening in the cortex near the endodermis was promoted by drought, but apparently not by waterlogged conditions.     

棉花油分合成相关基因的SSCP标记开发

本研究根据棉花油份合成相关基因(lysophosphatidic acid acyltransferase,LPAAT; diacylglycerol acyltransferase,DGAT; phosphoenolpyruvate carboxylase,PEPC)设计了75对引物,在8个棉花品种中运用SSCP技术...     

中国美利奴羊不同MHC-DRB1/DQB1单倍型个体感染细粒棘球绦虫的免疫应答分析

为探讨中国美利奴羊(新疆军垦型)不同单倍型个体感染细粒棘球绦虫的免疫应答变化。将8只抗性单倍型绵羊设为抗性组,8只非抗性单倍型绵羊设为对照组,在相同的饲养条件下进行人工感染攻虫。分别在攻虫前7d(-7d)、攻虫当天(0d)、攻虫后第7、21、30、60天用流式细胞仪分析外周血中CD4+T、CD8+T、B淋巴细胞亚群的变化,同时用ELISA方法定量分析血清中IgG、IgM、IgE、IFN-γ水平并进行粒细胞计数。结果表明,抗性组绵羊的发病率显著低于对照组(P=0.019);CD4+T细胞2组之间差异不显著(P0.05),CD8+T细胞在攻虫后第7天抗性组显著高于对照组(P0.05);IgG水平在攻虫后第7天2组均显著高于攻虫前7d(P0.05)。攻虫后第30天抗性组IgM和IFN-γ水平均显著高于对照组(P0.05)。抗性组的白细胞、淋巴细胞分别在攻虫后第7和21天显著高于对照组(P0.05),嗜中性粒细胞和总蛋白在攻虫后第21天抗性组极显著低于对照组(P0.01)。结果显示,抗性单倍型绵羊对细粒棘球绦虫的抵抗力显著高于非抗性绵羊;抗性组绵羊体内的CD8+T细胞、IgM、IFN-γ和白细胞、淋巴细胞水平在攻虫后不同时期显著高于非抗性组绵羊。     

杨树伐根嫁接亲和力研究

以小美旱杨为砧木,选择了9个杨树品种作接穗进行伐根嫁接,研究了伐桩与接穗的亲和力。结果表明:以小美旱杨为伐桩,嫁接038杨,中林46杨,107杨,108杨,埃瑞达诺110杨,中林2001杨,中林2025杨和转基因杨的伐桩成活率均高于97.8%,第4年伐桩保存率均高于92.8%,可以满足林业生产的需要,表现出良好的亲和力。     

浅谈当前农村财政补贴农民资金现状、问题及对策建议

从当前我国财政补贴农民资金的现状和存在的问题出发,分析其产生的原因,并提出相应的对策,以供参考和指导。     

Seroprevalence of chlamydial infection in dairy cattle in Guangzhou, southern China

Chlamydia spp. are obligate intracellular gram-negative bacteria that cause a wide range of significant diseases in humans and animals worldwide, resulting in significant economic losses. Chlamydial infection in cattle has been reported in many countries including China. However, there has been no survey of chlamydial infection of dairy cattle in Guangzhou, southern China. The objective of the present investigation was to examine the chlamydial seroprevalence in dairy cattle in Guangzhou, subtropical southern China by using an indirect hemagglutination assay (IHA). The overall seroprevalence of chlamydial infection in dairy cattle was 7.25% (29/400). Greater than or equal to eight-yr-old dairy cattle had the highest seroprevalence (10.34%), followed by those that were ≥ 6 years old or < 7 years old dairy cattle (10.20%), although there were no statistically significant differences among different groups (P > 0.05). Dairy cattle with 5 pregnancies had the highest seroprevalence (10.81%). These results indicate that chlamydial infection was present in dairy cattle in Guangzhou, subtropical southern China, and integrated strategies and measures should be executed to control and prevent chlamydial infection and disease outbreak in the study region.     

Studies on hollownesss regulation and properties of crosslinked hollow phenolic fibers

The hollowness of crosslinked hollow phenolic fibers was regulated successfully from 9 % to 80 % by adjusting the curing temperature of the partially crosslinked fibers. The partially crosslinked fibers was studied in detail by mass gained, tensile strength, solvent dissolution, SEM, IR, and TG analysis, and the prepared hollow phenolic fibers with different degrees of hollowness were characterized with SEM, tensile strength, TG-DSC and TG-MS. The results show that the factor determining the hollowness is the crosslinked extent of the partially crosslinked fibers and the hollow fibers with different degrees of hollowness have similar crosslinkage, mechanical properties and thermal stability.     

Performance of four Chinese Trichogramma species as biocontrol agents of the rice striped stem borer, Chilo suppressalis, under various temperature and humidity regimes

The striped stem borer, Chilo suppressalis (Walker), is one of the most economically important rice pests worldwide. However, biological control of this pest using natural enemies has rarely been documented. Indigenous natural populations of four Trichogramma species (i.e., T. japonicum, T. chilonis, T. dendrolimi, and T. ostriniae) were collected from the eggs of C. suppressalis in paddy fields. With the objective of screening suitable candidate species for controlling the striped stem borer, parasitism by these four Trichogramma species of the eggs of their native host, C. suppressalis, was evaluated at five temperatures (18, 22, 26, 30, and 34?°C) and four relative humidity (RH) regimes (30, 50, 70, and 90?%). The temperature and the humidity significantly affected the ability of all of the Trichogramma species to parasitize the eggs of their host. T. chilonis parasitized more eggs at 26?°C than at the other temperatures. By contrast, T. dendrolimi, T. ostriniae, and T. japonicum performed best within a wider temperature range. The host number parasitized was highest at 70?% RH and differed significantly among the Trichogramma species at all of the temperatures and humidities tested, except at 30?°C and 50?% RH. Generally, T. dendrolimi and T. japonicum performed better than the other species at 18–26 and 30–34?°C, respectively, whereas T. ostriniae parasitized the fewest host eggs at 30–70?% RH. Both T. dendrolimi and T. japonicum appear to be promising candidates for augmentative release against C. suppressalis in northeastern China.     

微生物菌剂对山杨不同品系造林的影响

微生物菌肥是一种对环境友好,效果持久的新型生物肥料,目前在林业生产中很少被使用,相关的研究也鲜有报道,本文是微生物菌肥在林业上应用的尝试。实验结果表明,微生物菌剂可以提高山杨的造林成活率,总体提高16%,但是因品种不同而效果迥异;对于植株的高生长有一定的抑制作用,这需要进一步的查明原因;微生物菌剂处理和品种间有显著的交互效应。结论认为,该微生物菌剂在山杨造林方面不是十分适用的,需要进一步开发出适宜的菌剂,主要是筛选出适合当地环境的放线菌菌株,以及改进配方和多种微生物混合制剂。     

浅谈大扩孔桩施工技术

本文详尽地叙述了大扩孔桩在基础施工中应采取的施工技术。