乡土树种在成都市公园绿地中的应用探析

对成都市8个主要城市公园已应用的园林树种进行系统调查,并针对当前乡土树种在应用当中存在的一些问题,提出了针对性的对策和建议。结果显示:成都市区公园中已应用的乡土树种有103种,占整个树种总数的63.19%,外来树种60种,占整个树种总数的36.81%;部分外来树种长势较差,与当地的植物特色不协调;近几年来乡土树种在公园绿化中越来越不受重视。     

咸宁市温泉城区行道树的选择与配置分析

对咸宁市温泉城区的主次干道行道树的选择与配置进行分析发现咸宁市温泉城区的主次干道行道树种类包含22科29属31种,且行道树绿化具有层次感较强,对观花、观叶和观果行道树树种的运用较到位,造型独特,绿化量较丰富等优点,但行道树配置也存在色彩单一、季相变化不明显、没有考虑到其他园林要素、乡土树种运用不够充分且缺乏人性化等问题。因此,提出了咸宁市温泉城区的主次干道绿化应合理选择行道树、均匀分布城市绿化量、充分且合理运用乡土树种等建议。     

彩叶植物岭南槭研究进展及展望

岭南槭是优良的乡土彩叶树种和观果树种。简介岭南槭的基本特征(系统分类、形态特征、种子表型、生长环境),综述岭南槭的育苗方式(播种育苗、嫁接育苗、扦插育苗)、苗期生长、园林应用(叶色特征、美景度评价)等方面的研究进展,展望其研究利用前景。     

云南省乡土园林植物区划探析

针对云南省绿化树种种类单一、植物景观趋同以及物种资源埋没等现状问题,作者以乡土园林植物为研究对象,在大量植物生物学特性和生态习性分析的基础上,迎合云南省特色明显、风情多样的景观文化和民族历史优势,将丰富多样的云南省乡土植物资源区划为5个大区和15个亚区,为园林工作者选择植物提供理论参考。     

关于黄土丘陵典型地区植被建设中有关问题的研究Ⅲ、乡土树种在造林中的意义

根据调查资料,论述了外来种和乡土树种在土壤水分,林下自然条件下更新等方面的有利和不利因素,探讨了经济效益,乡土树种的不可替代作用等问题,最后提出了"延安试验研究区造林应以乡土树种为主体,辅以外来树种"的思路,针对这一思路提出了对策.     

关于黄土丘陵典型地区植被建设中有关问题的研究：Ⅲ,乡土树？…

根据调查资料,论述了外来种和乡土树种在土壤水分,林下自然条件下更新等方面的有利和不利因素,探讨了经济效益,乡土树种的不可替代作用等问题,最后提出了“延安试验研究区造林应以乡土树种为主体,辅以外来树种”的思路,针对这一思路提出了对策。     

龙塔公园寺庙园林植物景观的设计与营造

在重庆市渝北区龙塔公园植物景观的设计与营造中,通过了解植物的文化内涵及特性,植物选择遵从体现佛教教义,因地制宜地运用乡土树种,使其体现寺庙园林相应的文化氛围,有利于通过植物延续寺庙园林的意境,创造出赏心悦目的景观效果和适于游人休憩游赏的园林空间.     

清香木育苗及造林技术要点

清香木是一种适应性强、耐干旱瘠薄、对土壤要求不严、病虫害少、抗空气污染力强的优良造林树种和城市绿化树种,在药用方面也有较高的价值。基于此,结合昆明市乡土树种的推广应用,总结归纳了林场清香木育苗技术和造林技术。     

乡土植物在娄底市园林绿化中的应用初探

乡土树种在园林绿化中具有重要作用,因此越来越受到人们的重视和喜爱。基于此,阐述了乡土树种的概念、优特点和作用,分析了娄底园林绿化中乡土树种应用现状及前景,并对乡土树种在园林绿化中的应用提出一些可行的建议。     

生态林业建设中乡土树种的应用措施浅析

近年来,人们越来越关注生态林业建设中的乡土树种种植情况。乡土树种在生态林业建设中具有先天优势,能够有效提升生态林业建设质量。基于此,分析了乡土树种在生态林业建设中的优势和当前生态林业建设现存问题,重点研究了生态林业建设中乡土树种的应用措施。     

Accumulation of copper in soils and leaves of tomato plants in greenhouses in Turkey

Copper (Cu)‐containing fertilizers, fungicides, and bactericides has been used extensively in the greenhouses in the Antalya province in recent decades with the use of such materials tending to increase year by year. The level of DTPA‐extractable Cu was determined in 210 soils (0–20 and 20–40 cm depth) and 105 leaf samples obtained from 105 tomato greenhouses. The DTPA‐extractable Cu contents of the soils taken from the 0–20 depth ranged between 0.76 and 88.03 mg kg^‐1 (mean 7.79 mg kg^‐1). The percentage of soils containing DTPA‐extractable Cu greater than the critical toxicity level (20 mg kg^‐1) was 8.1. The Cu content of tomato leaf samples ranged between 2.4 and 1,490 mg kg^‐1 (mean 166.5 mg kg^‐1). The Cu concentration in leaf samples was very high due to the intensive use of foliar applied Cu‐containing chemicals. As a consequence, 24.8% of the leaf tomato samples analyzed contained over 200 mg Cu kg^‐1, the maximum accepted tolerance level. Therefore, it may be necessary to reduce the use of Cu‐containing pesticides and fertilizers, or at least reduce the amount of Cu‐containing fertilizers being used in those greenhouses where Cu‐containing pesticides have been or are being used.     

Role of selenium in mitigation of cadmium toxicity in pepper grown in hydroponic condition

Selenium (Se) is an essential element for humans but is not considered as essential for plants. However, its beneficial role in improving plant growth and stress tolerances is well established. In order to study the role of Se in cadmium (Cd) toxicity in pepper (Capsicum frutescens cv. Suryankhi Cluster), this experiment was carried out in greenhouse conditions. Treatments comprised Cd [0, 0.25, and 0.5 mM cadmium chloride (CdCl₂)] and Se [0, 3, and 7 µM sodium selenite (Na₂SeO₃)] with three replications. The result showed that Cd decreased chlorophyll a, chlorophyll b, and carotenoids, whereas Se supplementation diminished Cd toxicity on photosynthetic pigment. Selenium at 7 µM significantly increased the leaf area in the plants grown at 0.25 mM Cd. The application of Se at 3 µM with 0.25 mM Cd and Se at 3 µM and Se at 7 µM with 0.5 mM Cd increased the activity of catalase (CAT). Selenium at 7 µM decreased the proline content of pepper leaves exposed to Cd at 0.5 mM (30%). Selenium significantly enhanced the antioxidant activity of leaves, which was diminished by Cd toxicity. In general, Se has a beneficial effect on plant growth and is an antioxidant enzyme of pepper cv. Suryankhi Cluster under Cd stress and non-stress conditions.     

红壤区不同肥力水稻土根际硝化作用特征

通过根际培养箱(三室)——速冻切片技术研究了红壤地区高、低两种肥力下水稻苗期根表、根际和土体土壤矿质态氮含量和硝化强度,以及水稻生长、氮素积累的差异。结果表明,肥力水平对水稻根表和根际土壤铵态氮(NH4+-N)含量无显著影响,但高肥力显著提高土体土壤NH4+-N含量,以及根表、根际和土体土壤硝态氮(NO3--N)含量及硝化强度。两种肥力水稻土硝化强度最大值均出现在距根表2 mm处,分别为0.20和0.31μmol kg-1 h-1。土体土壤硝化强度随距根表距离增加而降低,低肥力土壤在距根表10～40mm处时硝化强度接近本底值,而高肥力土壤在距根表20～40 mm处时接近本底值。与不种水稻的CK相比,种植水稻显著提高根际土壤硝化强度。高肥力能显著改善水稻生长,增加植株氮素积累量,尤其显著促进根系生长及通气组织发育。由于红壤稻田肥力水平的差异造成水稻根际硝化强度以及水稻吸收NO3-的差异,导致高肥条件下水稻显示出更强的生长势和氮素吸收利用能力。因此,合理提高红壤稻田肥力水平对改善红壤区水稻根际土壤硝化作用及水稻氮素营养具有重要意义。     

自由基在鸡肾病发生中的作用研究

肾病即急性肾小管坏死.鸡肾病在养鸡生产中极为常见,尤其近年来,鸡肾病的发生日益增多,由于其发生机制不清楚,临床治疗鸡肾病的依据不足,致使治疗效果不佳,为此,提出本研究以探讨鸡肾病的发生机制,为本病防治提供理论依据.     

Occurrence of Sexual Hormones in Sediments of Mangrove in Brazil

The presence of sexual hormones (female estrogens) was assessed in sediments of a mangrove located in the urban region of southern Brazil. The estrogens are involved in human sexual reproduction. They act as the chemical messengers, and they are classified as natural and synthetic. The estrogens inputs in the environment are from treated and untreated sewage. The presence of estrogens in sewage is excretion from the female due to natural production and use of contraceptives (synthetic estrogens). With the indiscriminate release of sewage into the environment, estrogens can be found in rivers, lakes, and even in oceans. In this work, the presence of estrone (E1), 17-??-estradiol (E2), and 17-??-ethynilestradiol (EE2) in eight sedimentary stations in Itacorubi mangrove located on Santa Catarina Island, south Brazil, was investigated. Historically, the Itacorubi mangrove has been impacted by anthropogenic activities because the mangrove is inserted in the urban area of the Florianopolis. The estrogen EE2, used as contraceptive, had the highest concentration in mangrove sediment, 129.75?±?3.89 ng/g. E2 was also found, with its concentration ranging from 0.90?±?0.03 to 39.77?±?1.19 ng/g. Following the mechanism, under aerobic or anaerobic conditions, E2 will first be oxidized to E1, which is further oxidized to unknown metabolites and finally to CO₂ and water (mineralized). EE2 is oxidized to unknown metabolites and also finally mineralized. Theoretically, under anaerobic conditions, EE2 can be reduced to E1 even in environments such as mangrove which is essentially anaerobic.     

Meta-analysis in the Selection of Groups in Varieties of Citrus

Brazil is the largest producer of oranges (Citrus sinensis) in the world. The nutrient management of tree orchards is designed from experiments with a limited number of varieties. This knowledge is transferred to other varieties by diagnosing tissue nutrient composition and tree demand. Compositional data analysis has been first applied to tissue analysis of agricultural crops using centered log ratios with compositional nutrient diagnosis (CND-clr). The isometric log ratio (ilr) transformation is a new approach based on binary nutrient ratios and the principle of orthogonality (CND-ilr). We analyzed eleven nutrients: nitrogen (N), sulfur (S), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), boron (B), copper (Cu), zinc (Zn), manganese (Mn), and iron (Fe) in leaf tissue samples across 108 commercial plots (thirty-one grow Valencia, twenty-two Hamlim, twenty Pera, and thirty-five Natal). Nutrients were partitioned between macro- and micronutrients as well as anionic and cationic species. The effect size of varieties over Valencia was quantified by the mean and standard deviation of ilr values across ilr coordinates. Specific varietal nutrient profiles and ilr norms were defined. The nutrient profile of orange varieties could be classified into homogeneous groups to take advantage of fertilizer trials conducted on varieties of the same group. The Aitchison distance and a perturbation vector could be instrumental for diagnostic purposes and nutrient management.     

Effect of iron-quercetin complex on reduction of nitrite in in vitro and in vivo systems

This study investigated whether reducing agents such as quercetin and iron(II) facilitate formation of nitric oxide (NO) gas from orally ingested nitrite in an vivo study. When 3 mg/kg Na (15)NO2 was orally administered to rats with or without iron(II) or quercetin, Hb (15)NO, which is indicative of systemic (15)NO, was detected in the blood, with the maximum blood concentration of Hb (15)NO at 15 min after nitrite or nitrite plus quercetin treatment, whereas after administration of nitrite plus iron(II) or nitrite plus iron(II) and quercetin, the time was shortened to 10 min. Interestingly, iron(II), quercetin, or iron(II) plus quercetin did not affect the total amount of Hb (15)NO generated from orally administered Na (15)NO2. However, the systemic nitrite concentration was significantly decreased in the presence of iron(II) or iron(II) plus quercetin. These results may indicate that iron(II) is critical to the generation of NO gas from nitrite, whereas quercetin contributed little under the in vivo experimental conditions.     

旱地果园水肥管理模式研究进展

分析了旱地果园水肥管理模式的研究进展和存在问题,指出水肥胁迫尤其是水钾已成为旱区果树高产稳产优质化的主要限制因子。在系统探讨旱地果园水分管理、养分管理、综合管理以及果树叶营养综合诊断施肥标准的基础上,提出了旱地果园的高效水肥管理模式。     

Role of aldehyde oxidase in the hepatic in vitro metabolism of 3-methylindole in pigs

The metabolism of 3-hydroxy-3-methylindolenine (HMI), a recently discovered metabolite of 3-methylindole (3MI, skatole) produced by porcine liver microsomes, was investigated in vitro using porcine liver cytosol. HMI was rapidly metabolized to a single product, 3-hydroxy-3-methyloxindole (HMOI), by porcine cytosol. By the use of the selective inhibitors menadione and quinacrine, it was shown that the enzyme responsible for the oxidation of HMI into HMOI was aldehyde oxidase (AO; aldehyde:oxygen oxidoreductase, EC 1.2.3.1). The activity of AO in the conversion of HMI to HMOI was measured in a population of pigs (n = 30) with a wide range of 3MI levels in back fat (0.07-0.30 mg/kg). AO activity was found to be negatively correlated (r = -0.70; P < 0.001) with the level of 3MI in fat. The results of the present study suggest that AO plays an important role in the metabolism of 3MI in the pig and that its catalytic activity is related to an adequate 3MI clearance.     

北京市郊典型农田施肥研究与分析

通过问卷调查形式,对京郊粮田、菜田和果园3种农田施肥现状进行研究.结果表明,菜田和果园化肥施用量较高,氮、磷、钾肥均显著高于粮田.菜田和果园氮肥用量分别为1741.0和1172.8 kg/hm2,分别是粮田氮肥用量的4.5和3.0倍;磷肥用量分别为1375.1和996.4 kg/hm2,分别是粮田磷肥用量的15.5倍和11.2倍;钾肥用量分别为791.3和602.4 kg/hm2,分别是粮田钾肥用量的21.1和16.1倍.另外,3种利用方式的农田氮、磷和钾肥施用比例不同,粮田为75.4%、17.3%和7.3%;果园为42.3%、36.0%和21.7%;而菜田为44.6%、35.2%和20.3%.3种种植类型中均存在氮肥投入过量、钾肥不足的问题.