接种蚯蚓对油菜籽粒产量和含油率的影响

通过田间接种试验,研究了威廉腔环蚓(Metaphire guillelmi)活动对冬油菜(Brassica napus)中双9号产量构成因素、籽粒产量和含油率的影响.结果表明:接种蚯蚓后,中双9号的一次有效分枝数、主花序角果数、每角粒数和千粒重均较未接种对照有增加趋势,但差异不显著;而单株角果数、单株产量和小区产量较对照显著提高,分别比对照增加了36.7%、46.5%和29.7%,这可能与蚯蚓促进油菜营养生长阶段植株生长及对氮素的吸收、累积有关.接种蚯蚓后,油菜籽粒含油率较对照有所降低,但由于蚯蚓活动显著提高了油菜籽粒产量,因此单株产油量和小区产油量仍比对照提高了37.4%和21.0%.     

基于城市土地利用类型的地表温度与植被指数的关系

以沈阳市三环作为研究区域,基于QuickBird、Landsat/TM遥感影像和GIS空间分析技术,获取城市土地利用信息,陆地表面温度(LST)以及归一化植被指数(NDVI),定量分析了LST与NDVI在不同城市土地利用类型之间的差异及空间关系.结果表明:LST和NDVI具有明显相反的变化趋势,城市不同土地利用类型的LST与NDVI平均值也具有显著的差异性;多重比较发现,LST和NDVI在两两土地利用类型之间的差异不同;LST与NDVI相关性的显著程度受空间尺度的影响,LST与NDVI的相关性随空间尺度变化呈现出先增加后降低再逐渐增加的趋势.研究结果可为城市规划以及城市绿地系统规划中缓解城市热岛效应提供科学依据.     

提取工艺和植物生长调节剂对罗布麻愈伤组织中黄酮含量的影响

以罗布麻愈伤组织粉末为材,在单因素实验的基础上,利用响应曲面法对罗布麻愈伤组织中黄酮的提取工艺进行优化。响应曲面分析结果表明,提取试剂和提取温度对提取的黄酮含量存在显著影响。通过响应曲面分析得到罗布麻愈伤组织中黄酮提取的最佳条件为:提取试剂为70%甲醇,物料比1∶40,提取时间为4 h,提取温度为70℃。培养并比较了30种不同植物生长调节剂浓度与配比诱导100 d生长的愈伤组织中黄酮的含量,结果得出MB+KT(1.0 mg/L)+NAA(0.2 mg/L)上培养约100 d的愈伤组织中黄酮含量最高,为73.90mg/g。测定愈伤组织培养30 d内黄酮的积累动态,探明从培养的愈伤组织提取黄酮的最佳时段。通过优化提取工艺和筛选最佳植物生长调节剂浓度与配比,运用组织培养技术提高了罗布麻愈伤组织中黄酮含量。     

沉香叶提取工艺及其抗氧化活性实验研究

采用单因素分析方法和正交试验法研究沉香叶提取工艺并评价沉香叶的体外抗氧化活性.沉香叶的最佳提取工艺为:以15倍量的60％乙醇为溶剂,超声提取40 min,提取1次.野生沉香叶和栽培沉香叶的氧化时间分别为(11.53±0.08)s和(9.98±0.16)s;超氧阴离子的清除率分别为(36.26±0.96)％和(35.67±1.25)％,总还原力的吸光度分别为0.188±0.008和0.129±0.011.该提取工艺简单、重复性好、提取液抗氧化活性强、工艺稳定、无污染;野生沉香叶和栽培沉香叶均具有较好的体外抗氧化活性.     

八角叶总黄酮的提取及其捕获自由基作用研究

目的:为八角叶资源的合理开发和利用提供科学依据。方法:分别以乙醇、石油醚、水等作提取溶剂,用超声波与非超声波对比提取八角叶总黄酮,考察在不同温度、溶剂浓度、超声波功率、提取时间等不同条件下用超声波/乙醇浸提法提取八角叶总黄酮,对所提取的黄酮类物质进行验证,并用分光光度法测定含量,用八角叶总黄酮对羟自由基清除作用进行试验。结果:超声波乙醇浸提法提取八角叶总黄酮的最佳工艺条件为:溶剂90%乙醇,温度80℃,超声波功率60 W,提取时间3.0 h。百色、南宁、贺州、河池、钦州所产八角叶总黄酮的含量分别为0.1649mg/mL、0.1022 mg/mL、0.1122 mg/mL、0.1850 mg/mL、0.1693 mg/mL,八角叶总黄酮提取液对Fenton体系产生的.OH自由基有很好的清除作用。结论:超声波乙醇浸提法提取八角叶总黄酮的效果最佳,产总黄酮含量最高,提示八角叶具有较高的开发利用价值。     

2个果梅品种雌蕊分化进程及相关生化指标分析

为了解果梅(Prunus mume Sieb.et Zucc.)雌蕊分化进程及其败育机制,采用石蜡切片法观察了不同时期果梅品种‘龙眼’(‘Longyan’)和‘大嵌蒂’(‘Daqiandi’)花芽纵切面的解剖结构,并对2个品种不同时期花器官发育状况、花芽百分率、花芽纵径和横径以及花芽中的可溶性糖、可溶性蛋白质和淀粉含量进行了测定分析.结果显示:雌蕊分化期、雌蕊分化末期及盛花期,品种‘龙眼’的不完全花比例均显著小于品种‘大嵌蒂’,其中,盛花期‘龙眼’不完全花比例仅为5.0％,而‘大嵌蒂’不完全花比例高达76.3％.品种‘龙眼’雌蕊分化过程经历未分化期、分化初期、分化期及分化末期4个阶段,且最终有95.0％的花芽在分化末期能顺利形成完全花;品种‘大嵌蒂’雌蕊分化过程则包含未分化期、分化初期、分化期、解体期、解体后修复期和分化末期6个阶段,且仅有23.7％的花芽能形成完全花.雌蕊分化的不同阶段2个品种花芽纵径和横径的变化与其分化进程基本一致.品种‘龙眼’完全花的可溶性糖和可溶性蛋白质含量均高于品种‘大嵌蒂’的完全花和不完全花、淀粉含量则低于后两者;品种‘大嵌蒂’不完全花的可溶性糖和可溶性蛋白质含量最低、淀粉含量则最高,与2个品种的完全花有显著差异.综合分析结果表明:品种‘大嵌蒂’的花芽在12月中上旬停止伸长生长、雌蕊分化停滞直至逐渐解体,这一时期即为品种‘大嵌蒂’雌蕊败育的关键时期;导致果梅雌蕊选择性败育的原因可能与花芽中大分子营养物质的分解代谢有关.     

酵母脂肪酶的制备及应用新进展

脂肪酶是工业领域应用非常广泛的一类绿色生物催化剂,由于脂肪酶可催化酯水解、酯化、转酯化、醇解和氨解等多种反应,在食品加工,有机合成,制备生物柴油等方面均得到了较为广泛的应用,是目前的研究热点.微生物是脂肪酶的重要来源之一,其中酵母脂肪酶被认为是非常安全的一类脂肪酶,也是应用最为广泛的一类脂肪酶.该文介绍了酵母脂肪酶的制备和应用研究概况,重点综述了其在多个应用领域中的最新研究进展.挖掘更多的新型高活性脂肪酶,降低脂肪酶的生产成本,提高酶的重复使用率是今后脂肪酶应用研究亟待解决的问题.     

Effect of precipitation variability on net primary production and soil respiration in a Chihuahuan Desert grassland

Precipitation regimes are predicted to become more variable with more extreme rainfall events punctuated by longer intervening dry periods. Water‐limited ecosystems are likely to be highly responsive to altered precipitation regimes. The bucket model predicts that increased precipitation variability will reduce soil moisture stress and increase primary productivity and soil respiration in aridland ecosystems. To test this hypothesis, we experimentally altered the size and frequency of precipitation events during the summer monsoon (July through September) in 2007 and 2008 in a northern Chihuahuan Desert grassland in central New Mexico, USA. Treatments included (1) ambient rain, (2) ambient rain plus one 20 mm rain event each month, and (3) ambient rain plus four 5 mm rain events each month. Throughout two monsoon seasons, we measured soil temperature, soil moisture content (θ), soil respiration (R_s), along with leaf‐level photosynthesis (A_net), predawn leaf water potential (Ψ_pd), and seasonal aboveground net primary productivity (ANPP) of the dominant C₄ grass, Bouteloua eriopoda. Treatment plots receiving a single large rainfall event each month maintained significantly higher seasonal soil θ which corresponded with a significant increase in R_s and ANPP of B. eriopoda when compared with plots receiving multiple small events. Because the strength of these patterns differed between years, we propose a modification of the bucket model in which both the mean and variance of soil water change as a consequence of interannual variability from 1 year to the next. Our results demonstrate that aridland ecosystems are highly sensitive to increased precipitation variability, and that more extreme precipitation events will likely have a positive impact on some aridland ecosystem processes important for the carbon cycle.     

Effect of climate change over the past half century on the distribution,extent and NPP of ecosystems of Inner Mongolia

The response of natural vegetation to climate change is of global concern. In this research, changes in the spatial pattern of major terrestrial ecosystems from 1956 to 2006 in Inner Mongolia of China were analyzed with the Holdridge Life Zone (HLZ) model in a GIS environment, and net primary production (NPP) of natural vegetation was evaluated with the Synthetic model, to determine the effect of climate change on the ecosystem. The results showed that climate warming and drying strongly influenced ecosystems. Decreased precipitation and the subsequent increase in temperature and potential evapotranspiration caused a severe water deficiency, and hence decreased ecosystem productivity. Climate change also influenced the spatial distribution of HLZs. In particular, new HLZs began to appear, such as Warm temperate desert scrub in 1981 and Warm temperate thorn steppe in 2001. The relative area of desert (Cool temperate desert scrub, Warm temperate thorn steppe, Warm temperate desert scrub, Cool temperate desert and Warm temperate desert) increased by 50.2% over the last half century, whereas the relative area of forest (Boreal moist forest and Cool moist forest) decreased by 36.5%. Furthermore, the area of Cool temperate steppe has continuously decreased at a rate of 5.7% per decade; if the current rate of decrease continues, this HLZ could disappear in 173 years. The HLZs had a large shift range with the mean center of the relative life zones of desert shifting northeast, resulting a decrease in the steppe and forest area and an increase in the desert area. In general, a strong effect of climate change on ecosystems was indicated. Therefore, the important role of climate change must be integrated into rehabilitation strategies of ecosystem degradation of Inner Mongolia.     

Coordinated approaches to quantify long‐term ecosystem dynamics in response to global change

Many serious ecosystem consequences of climate change will take decades or even centuries to emerge. Long‐term ecological responses to global change are strongly regulated by slow processes, such as changes in species composition, carbon dynamics in soil and by long‐lived plants, and accumulation of nutrient capitals. Understanding and predicting these processes require experiments on decadal time scales. But decadal experiments by themselves may not be adequate because many of the slow processes have characteristic time scales much longer than experiments can be maintained. This article promotes a coordinated approach that combines long‐term, large‐scale global change experiments with process studies and modeling. Long‐term global change manipulative experiments, especially in high‐priority ecosystems such as tropical forests and high‐latitude regions, are essential to maximize information gain concerning future states of the earth system. The long‐term experiments should be conducted in tandem with complementary process studies, such as those using model ecosystems, species replacements, laboratory incubations, isotope tracers, and greenhouse facilities. Models are essential to assimilate data from long‐term experiments and process studies together with information from long‐term observations, surveys, and space‐for‐time studies along environmental and biological gradients. Future research programs with coordinated long‐term experiments, process studies, and modeling have the potential to be the most effective strategy to gain the best information on long‐term ecosystem dynamics in response to global change.