Radiation interception and radiation use efficiency of potato affected by different N fertigation and irrigation regimes

Three years of field experiments were carried out to explore the response of potato dry matter production, accumulated intercepted photosynthetic active radiation (Aipar) and radiation use efficiency (RUE) to five N levels providing 0, 60, 100, 140 and 180 kg N ha⁻¹ and three drip irrigation strategies, which were full, deficit and none irrigation. Results showed that, irrespective of years, dry matter production and Aipar were increased by prolonged N fertigation, even though N fertigation was carried out from middle to late growing season. The highest total and tuber dry matter and accumulated radiation interception in all three years were obtained when potatoes were provided with 180 kg N ha⁻¹. RUE on the other hand was not affected by N regime. Thus, increases in total dry matter production with increasing N levels were essentially caused by higher Aipar. The strongest response to N fertilization occurred when most N was applied early in the growing season and the latest N fertilization should be applied no later than 41–50 days after emergence. Deficit irrigation, which received ca.70% of irrigation applied to full irrigation, did not reduce radiation interception and radiation use efficiency.     

毛乌素沙地东南缘植被恢复中优势灌木的保育作用分析

以毛乌素沙地东南缘优势灌木作为保育植物,选择油松(Pinus tabulaeformis)和樟子松(Pinus sylvestris)幼苗作为目标物种,将其分别种植在开阔地和优势灌木冠层下,连续3 a统计松树幼苗的存活率和主枝生长长度,从而确定毛乌素沙地优势灌木对松树幼苗的定居是否存在保育作用。同时,测量开阔地和灌木冠层下的环境指标,揭示优势灌木保育作用产生的机理。结果表明:1优势灌木冠层下松树幼苗的总存活率显著高于开阔地(P0.05),说明优势灌木可增加松树幼苗的存活率。2在持续3 a的恢复实验期间,优势灌木对松树幼苗定居的保育作用不随时间的变化而发生改变。3优势灌木冠层下松树幼苗的主枝生长良好,并未受到抑制。4优势灌木通过改善微环境,从而对其冠层下松树幼苗的定居产生保育作用,其中改善最为明显的是光照强度和土壤湿度,其次是土壤的有机质和全氮含量。总的来说,优势灌木对松树幼苗的定居存在保育作用,保育植物技术可作为一种有效的恢复措施,应用在毛乌素沙地东南缘的植被恢复中,从而为该区植被的恢复与生态保护提供基础数据。     

1株解淀粉芽孢杆菌B7快速液态发酵优化工艺研究

本试验以1株饲用益生菌解淀粉芽孢杆菌B7（Bacillus amyloliquefaciens B7，B.amyloliquefaciens B7）为研究对象，为了增强其在液态条件下的发酵水平，提高其芽孢发酵工艺优化效率，拟采用测定芽孢吡啶二羧酸（dipicolonic acid，DPA）浓度的方法来代替传统的平板芽孢计数法，以探讨此测定方法在芽孢发酵优化工艺中的可行性。首先，通过单因素试验筛选出对菌株产孢有显著促进作用的因子，进一步通过正交优化试验确定蛋白胨、玉米粉、大米蛋白粉和Mn²⁺组合的最优水平。结果表明，发酵液中的芽孢浓度与测定的DPA荧光强度呈线性相关，在蛋白胨20 g/L、玉米粉10 g/L、大米蛋白粉20 g/L、Mn²⁺1.0 mmol/L时发酵48 h，检测到DPA荧光强度达到最大，其相应的芽孢浓度达到7.0×10⁹ CFU/mL。与实验室常用的LB培养基相比，芽孢浓度提高了3.3倍；与工业生产用培养基相比，芽孢浓度提高了2.2倍。本研究为芽孢杆菌发酵过程中芽孢浓度测定提供了一种快速方法，为工业菌株B.amyloliquefaciens B7的发酵提供了一种成分简单且高产芽孢的培养基。     

基于遥感的干旱监测方法研究

在全球变暖的气候背景下,近年来干旱频发且不断加剧,对人类的生产生活造成了严重的影响。目前,干旱监测已成为全球气候变化研究的一个热点课题。遥感技术以其客观、及时、经济、覆盖范围广、数据连续等优点,已被证明是干旱监测中最具前景的技术手段。本文基于遥感原理,介绍了归一化植被指数、温度状态指数、标准化降雨指数和标准化降雨蒸散指数等几种常见的干旱指数,综述了运用不同指数干旱监测的主要应用。最后针对目前研究中存在的问题,对今后研究的主要方向作出了展望。     

Diets of endangered silver chub (Macrhybopsis storeriana,Kirtland, 1844) in Lake Erie and implications for recovery

Silver chub (Macrhybopsis storeriana, Kirtland, 1844) is a native Cyprinid in Lake Erie, one of the Laurentian Great Lakes of North America. It is listed as endangered by the US state of New York and Canada, which has a recovery plan, and as special concern by the state of Michigan. Silver chub faces a potential threat to recovery from control efforts for invasive Grass carp (Ctenopharyngodon idella, Valenciennes 1844). Among the knowledge gaps for protection and restoration is current diet data. I describe the diet of silver chub from western Lake Erie in 2014, and I compare it to past studies to assess changes in diet through time. Silver chub captured in bottom trawls May–September 2014 were frozen in the field, and stomach contents were preserved in ethanol. Diet taxa were identified to the lowest practical taxonomic unit, then dried and weighed. Frequency of occurrence in silver chub diets was highest for Hexagenia spp. mayflies (79%). Dreissena spp. and Hexagenia spp. were both 41% of the diet by dry weight. Analysis of δ¹³C isotopes identified Hexagenia spp. as the primary source of carbon in silver chub. Compared to past studies, Dreissena spp. have mostly replaced Sphaeriidae and Gastropoda in silver chub diets. There also have been seasonal shifts in relative amounts of shelled organisms and Hexagenia spp. This study and past research suggest a functional link between silver chub and Hexagenia spp. abundance. Maintenance and recovery of silver chub may be dependent on maintaining Hexagenia spp. populations.     

地被植物紫花地丁的应用研究

对野生地被植物紫花地丁分别以播种、分株2种繁殖方式进行试验,观察其发芽、生长及习性。结果表明紫花地丁地面覆盖效果好、耐荫,适合本地区生长;叶形、花色美观,各方面抗性较强,可粗放管理,是难得的优良地被品种,值得大力推广。     

郏县文庙片区更新中历史文化资源的保护与利用

对河南郏县文庙片区的环境背景进行了分析,立足于其核心历史价值,对片区进行了详细规划设计。将片区的核心历史文化特色通过设计,在建筑、景观等层面表达出来,在保护古建筑的同时,借其核心优势,驱动整个片区的经济,并将部分收益返回来用于保护历史遗迹。通过案例的解析来阐明历史文化资源的有效保护利用手段。     

大巴山西段陕西米仓山自然保护区的植被及分布

为了系统掌握陕西米仓山自然保护区植被分布及其特点,合理有效开展资源保护工作。通过调查以及归类分析,建立了陕西米仓山自然保护区自然植被12个植被型37个群系,人工植被3个群系的植被分类系统,并对植被水平及垂直分布进行对比分析,对该区域植被分布所呈现的群落类型多样、自然性和代表性较强、过渡区的特征比较明显、植被在水平和垂直分布上存在一定差异以及植物群落的脆弱性高等特点进行了阐述。     

怀孕期高原鼢鼠生物学特征与环境因子的关系分析

选择甘肃天祝县高原鼢鼠(Mospalax baileyi)2个地理位置不同的栖息地为研究区,以高原鼢鼠体重、胎数、妊娠率和种群密度作为其生物学特征指标,以2011~2013年归一化植被指数(NDVI)、年均降水量和年均温度为环境因子,分析二者的相关关系。结果表明:2个研究区域NDVI存在显著性差异(P0.05);除了2011年和2013年雌性体重存在差异外,2个区域高原鼢鼠体重、妊娠率、平均胎数和种群密度均无显著性差异(P0.05);雌雄个体重和平均胎数与NDVI呈负相关关系,妊娠率和种群密度与NDVI呈正相关关系;雄性个体重、胎数和种群密度与年均温呈负相关关系,雌性个体重和妊娠率与年均温呈正相关关系;雄性个体重、妊娠率、胎数和种群密度与年均降水量呈正相关关系,雌性个体重与年均降水量呈负相关关系,但高原鼢鼠各生物学指标与环境因子相关性均不显著(P0.05)。说明,高原鼢鼠体重、妊娠率、胎数和种群密度的变化与栖息地环境因子没有直接关系,生物学特征受环境因子的影响较小。     

Effects of smoke,ash and heat shock on seed germination of seven species from Central Zagros rangelands in the semi-arid region of Iran

Fire products have been widely identified as germination cues for a number of species from both fire-prone and fire-free ecosystems. However, there is uncertainty about the effects of fire products on seed germination of semi-arid rangeland species. We examined the germination of seven dominant species from Central Zagros rangelands in the semi-arid region of Iran under various heat shock (60, 80 and 120 °C), aerosol smoke, ash and control treatments. Our findings showed that fire products could enhance, inhibit or not affect the seed germination of rangeland species in this area. The germination percentage of Astragalus adscendens increased following 60 °C heat treatment in comparison with the control. The germination of Astragalus verus, Bromus tectorum, B. tomentellus and Phlomis olivieri were increased significantly using smoke treatment (P<0.0001). The seed germination of B. tomentellus and B. tectorum was promoted by ash treatment, whereas the other species exhibited no response or were inhibited by fire products. In addition, smoke treatment shortened the overall germination time of B. tectorum. These findings suggest that fire products affect the germination of several species and can serve as potential tools for understanding the vegetation dynamics and restoration of disturbed semi-arid rangelands.