蜂毒肽获取方法的研究概述

蜂毒肽是蜂毒中的主要活性成分,作为典型的抗菌肽,具有镇痛、抗炎、抗病毒、抗肿瘤等药理活性,有较大的科学研究价值和广泛的医疗应用价值。但蜂毒肽纯品获取的高成本阻碍了其开发和应用。主要从蜂毒中分离纯化和生物工程技术应用两个方面概括和比较了目前获取蜂毒肽的方法,以期为相关研究提供参考。     

南方山区草地资源的类型及开发利用途径

根据生态学的基本原理，对我国南方山区草地资源的特点进行了分析，从生态学类型上对该地区草地进行了划分，进而提出了南方山区草地开发利用的途径。     

六盘山叠叠沟小流域4种植被土壤层水文调节功能的综合评价

深入认识和定量评价植被土壤层的水文调节功能,是干旱半干旱区生态工程建设和流域水土资源管理的重要科学依据。文中在宁夏六盘山北侧半干旱区的叠叠沟小流域,分析了4种典型植被(华北落叶松林、白桦林、沙棘灌丛和草地)100cm土层的土壤容重、持水能力和渗透性等土壤水文物理性质,运用坐标综合评定法定量评价了其土壤水文调节功能。结果表明:土壤容重(g/cm3)以沙棘灌丛(1.17)最高,白桦林、华北落叶松林和天然草地较接近(1.05~1.07);土壤总孔隙度表现为华北落叶松林(54.41%)>白桦林(53.30%)>天然草地(51.91%)>沙棘灌丛(50.11%);华北落叶松林和白桦林的蓄水性能和渗透性能要优于沙棘灌丛和草地。综合评价结果显示:白桦林地的土壤水文调节功能最强(0.0008),华北落叶松林地(0.0148)和沙棘灌丛(0.0678)次之,草地的土壤水文调节功能最差(0.2418)。     

芒果采后及贮藏生理研究进展

芒果是跃变型水果。采收后果实品质和代谢生理等发生重大变化,笔者从芒果果实的采后品质变化、呼吸强度、乙烯代谢、活性氧代谢、Ca2+对果实后熟的影响、逆境生理及不同采后处理对芒果采后生理的影响等方面,阐述了芒果采后和贮藏过程中的主要生理变化的研究进展,并指出了今后芒果采后保鲜的研究方向和研究内容。     

Heavy grazing effects on stem elongation and internode allometry: Insights from a natural pasture grass

Limited plant stem elongation is hypothesized to be the primary cause of decreased plant growth in response to long‐term heavy grazing (LHG). However, it remains largely unknown how LHG‐induced changes in stem elongation are mediated by internode traits. Accordingly, we experimentally investigated the effects of LHG (defined as twice the stocking rate recommended by the local government) on plant stem elongation and internode allometry in Leymus chinensis in Xilinhot, Inner Mongolia, China. Plant size and internode traits, including internode length (IL), internode diameter (ID), and internode number (IN), from plant individuals were measured according to their phytomer position from base to apex. The results revealed that IN and their distributions were changed in response to LHG. Although LHG negatively affected IL and ID of each L. chinensis internode from base to apex and eventually stem length, the plasticity index of IL and ID increased initially and then decreased from the lowermost to the uppermost internode in response to LHG. These contrasting responses of internode traits were result of allometry between internode traits determined by both LHG and internode position. Ultimately, IL and IN were identified to be key traits influencing stem length reduction under LHG conditions and explaining 52.51% and 47.49% of variation in stem length, respectively. Overall, our findings suggest that the limitation of L. chinensis stem elongation induced by LHG is mediated by the plasticity and allometry of internode traits. This result emphasizes the sensitivity of individual plants to LHG and is potentially valuable for optimal grassland management.     

高黎贡山南段大型真菌多样性研究

以随机路线踏查法为主,样地法为辅,对该区林下大型真菌进行较系统地调查,除随机踏查路线外,共选取8块标准样地,调查高黎贡山南段大型真菌资源情况。结果表明：该区内大型真菌种类223种,隶属46科、86属。其中食用菌77种,药用菌21种,毒菌25种,食药兼用菌15种,不明80种;易危1种,近危1种,无危101种,中国特有种8种。优势科为红菇科（Russulaceae）、多孔菌科（Polyporaceae）、丝膜菌科（Cortinariaceae）、牛肝菌科（Boletaceae）、蘑菇科（Agaricalceae）、小菇科（Mycenaceae）。优势属为红菇属（Russula）、乳菇属（Lactarius）、丝膜菌属（Cortinarius）、鹅膏属（Amanita）、小菇属（Mycena）、小皮伞属（Marasmius）、多孔菌属（Polyporus）、粉褶菌属（Entoloma）、蜡蘑属（Laccaria）、栓菌属（Trametes）、马勃属（Lycoperdon）、湿伞属（Hygrocybe）、小孔菌属（Microporus）,不同样地的优势属各有不同。区系地理成分具有明显的温带性质,与热带—亚热带大型真菌区系具有一定的关系,与云南大围山相似性较高。     

Effects of ionic surfactants on the aggregate stability and water repellency of silt loam soil

Purpose

With the increase of surfactant usages, more and more concerns were paid on their effects on the physicochemical characteristics of soils. Up to now, only few researches have examined the effects of ionic surfactants on the stability of soil structure and soil water repellency.

Materials and methods

Cetyltrimethyl ammonium bromide (CTAB) as cationic surfactant and sodium dodecyl sulfate (SDS) as anionic surfactant were adopted to investigate their effects on the aggregate stability and water repellency of a silt loam soil which was sampled in Corn High-Tech Park, Huang-Huai-Hai region, China. (1) Aggregate stability: 50 g soil was mixture with 100 mL surfactant solution in a beaker. The concentrations of surfactant solutions were 0 (the blank), 200, 400, 600, 800, 1000, and 2000 mg L^?1, respectively. After 30 min, the soil was sieved and divided into four fraction aggregates. (2) Soil water repellency: the concentrations of surfactant solutions were the same as experiment 1. Forty grams of soil was blended with 80 mL surfactant solution in an aluminum specimen. Drying the water by oven of 40 °C firstly and then by air, the whole period was about 1 week. After that, soil water infiltration and sorptivity were measured.

Results and discussion

Compared to the blank, surfactants increased the amounts of 2–0.25 and <0.053 mm aggregates of the soil and decreased the amounts of 0.25–0.053 mm aggregates of the soil. Surfactants also increased the mean weight diameter (MWD) of the soil. Except the 200 mg L^?1 treatment, CTAB promoted the soil water infiltration. All SDS treatments impeded the soil water infiltration. The soil repellency factor (R) value of the blank was 1.22, lower than the critical value of 1.95, which implied that the soil of blank treatment was free of soil water repellency. For CTAB, only 200 and 400 mg L^?1 treatment’s R were higher than 1.95 while for SDS, all the treatment’s R were higher than 1.95.

Conclusions

Surfactants improved the stability of soil aggregates. Soil treated with CTAB did not show the repellency, whereas SDS treatment resulted in intense water repellency compared with the wettable blank soil. Findings of this study can be used to explain the role of ionic surfactants on soil structure stability as well as on the development of water repellency in lower soil depths.

     

雄性不育与杂种优势育种(一)

<正> 在“雄性不育与杂种优势育种”这篇综述中,第一部分论述亚麻、洋葱、甜菜、玉米、高粱的杂优育种与有关遗传问题,第二部分重点讨论小麦与水稻的杂优育种与遗传。1、亚麻在作物中最先发现可遗传雄性不育现象的是亚麻。1921年贝特森报道说,他用     

Comparison of the florfenicol metabolic rate in Portunus trituberculatus individuals with different body weights

We analysed the metabolic rate of large individuals (LIs) and small individuals (SIs) (based on body weight) of 80‐day‐old specimens of Portunus trituberculatus injected with 40 mg/kg florfenicol (FLR). The results showed that FLR contents in the gills and hepatopancreas were higher in the SIs than in the LIs. The activities of erythromycin N‐demethylase and 7‐ethoxyresorufin‐O‐deethylase related to cytochrome oxidase P450 (CYP) were induced after FLR injection and showed a size‐dependent pattern; however, no significant difference in aminopyrine N‐demethylase activity was found between the LIs and SIs. The activity of the phase II enzyme glutathione S‐transferase (GST) increased in the hepatopancreas after FLR injection, and it was higher in the SIs than the LIs. Moreover, induction of CYP2, CYP3, GST, ABCB and ABCG was observed in the first 24 hr after FLR injection. FLR caused more biomolecular damage in the SIs than the LIs, displaying an obvious body weight‐ and time‐dependent pattern. In summary, the SIs exhibited faster FLR uptake and slower depuration in this species, and FLR caused more biomolecular damage to the SIs.     

土壤重金属污染及植物修复技术

土壤重金属污染是当今面一临的一个重要环境问题,而土壤重金属污染的植物修复是治理污染土壤的重要手段之一.作者概括了中国土壤重金属污染现状及危害,论述了植物修复技术的类型及其优缺点,并展望了植物修复未来的发展趋势.