Effects of phosphoroamides on ammonia volatilization and nitrite accumulation in soils treated with urea

Summary We compared the effects of N-(n-butyl) thiophosphoric triamide (NBPT), N-(diaminophosphinyl)-cyclohexylamine (DPCA), phenylphosphorodiamidate (PPD), and hydroquinone on transformations of urea N in soils. The ability of these urease inhibitors to retard urea hydrolysis, ammonia volatilization, and nitrite accumulation in soils treated with urea-decreased in the order NBPT > DPCA PPD > HQ. When five soils were incubated at 30°C for 14 days after treatment with urea (1 mg urea N g^–1 soil), on average, the gaseous loss of urea N as ammonia and the accumulation of urea N as nitrite were decreased from 52 to 5 % and from 11 to 1%, respectively, by addition of NBPT at the rate of 10 g g^–1 soil (0.47 parts of NBPT per 100 parts of urea). The data obtained support previous evidence that NBPT is more effective than PPD for reduction of the problems encountered in using urea as a fertilizer and deserves consideration as a fertilizer amendment for retarding hydrolysis of urea fertilizer in soil.     

2000—2020年喀斯特地区煤矿资源城市生态敏感性的时空演变

[目的] 以喀斯特地区典型煤矿资源城市贵州省六盘水市为例,分析研究区2000—2020年生态敏感性时空演变特征,为喀斯特地区煤矿资源城市的生态保护工作提供科学依据。[方法] 根据研究区实际,选择遥感生态指数、水土流失敏感性指数、石漠化敏感性指数、景观开发强度指数、碳排放量构建综合生态敏感性指数,并借助空间自相关分析方法分析六盘水市生态敏感性时空演变特征。[结果] ①2000—2020年,六盘水市极敏感、高度、轻度、中度敏感区域呈波动下降趋势,不敏感区持续上升,生态环境明显改善; ②2000—2020年六盘水市极敏感、高敏感区空间演变趋势为零散分布在全市,同时向东南部转移,并向西北部扩散,范围持续缩减,除钟山区南部有轻微扩散外,其余区域均呈现持续或波动缩减趋势,环境趋向于改善; ③2000—2020年六盘水市综合生态敏感性Global Moran’s I分别为0.525,0.570和0.476,说明六盘水市生态敏感性在空间上呈正相关关系,且相关性随时间变化而逐渐减弱。LISA图显示高高、低低聚集区减少,生态敏感性聚集程度有所降低。[结论] 六盘水市生态敏感性以轻度敏感为主,主要分布在生态禀赋较好的西北部地区;极敏感性区域比例较小,集中于自然条件较脆弱的东南部。随着时间推移,六盘水市的营造林等工程措施在一定程度上缓解了人类过度干预所带来的环境恶化,使区域内极敏感、高敏感区范围不断缩减,生态环境得到显著改善。     

日光温室地源热泵供暖碳足迹的生命周期分析

为分析日光温室地源热泵供暖的碳足迹,该文以日光温室地源热泵供暖系统中浅层地热能的存储、提取、制冷压缩提升和温室末端供暖整个过程为研究对象,对系统的温室气体排放和单位温室供暖面积的排放水平进行分析,构建基于生命周期分析LCA(life cycle assessment)的日光温室地源热泵供暖碳足迹分析方法。同时以北京地区日光温室地源热泵系统冬季供暖采集的试验数据为依据,分析和计算出北京地区日光温室在采用燃煤和燃气2种不同发电方式下地源热泵系统的供暖碳足迹和基于20 a和100 a温室地源热泵供暖碳足迹的全球变化潜能(global warming potential,GWP,单位为二氧化碳当量排放-CO2-eq.)的变化。研究表明,在北京地区采用燃煤和燃气驱动地源热泵系统的碳足迹GWP分别为257和72 g/(m2·d)。基于100 a的GWP总量比20 a的计算值分别减少了1.6%和5.4%。对比荷兰Venlo型温室天然气供暖,该研究中采用燃煤发电驱动日光温室地源热泵供暖的碳足迹是其1.39倍,而燃气发电驱动日光温室地源热泵供暖的碳足迹仅为Venlo型温室供暖的41%。采用燃气发电驱动的地源热泵供暖系统具有更低的碳足迹。     

Fe2（SO4）3/γ-Al2O3催化剂微波法玉米皮中提肌醇工艺研究

以玉米皮为原料制取菲丁,采用Fe2(SO4)3/γ-Al2O3固体酸催化剂,甘油做为水解促进剂,在常压微波辅助下催化水解菲丁制取肌醇,通过单因素及正交试验确定了最优工艺条件:辐射功率600w、水解时间70min、甘油配比为5、催化剂用量10g,在此条件下肌醇收率为72.69%。     

Synergistic antimicrobial activities of natural essential oils with chitosan films

The synergistic antimicrobial activities of three natural essential oils (i.e., clove bud oil, cinnamon oil, and star anise oil) with chitosan films were investigated. Cinnamon oil had the best antimicrobial activity among three oils against Escherichia coli , Staphylococcus aureus , Aspergillus oryzae , and Penicillium digitatum . The chitosan solution exhibited good inhibitory effects on the above bacteria except the fungi, whereas chitosan film had no remarkable antimicrobial activity. The cinnamon oil-chitosan film exhibited a synergetic effect by enhancing the antimicrobial activities of the oil, which might be related to the constant release of the oil. The cinnamon oil-chitosan film had also better antimicrobial activity than the clove bud oil-chitosan film. The results also showed that the compatibility of cinnamon oil with chitosan in film formation was better than that of the clove bud oil with chitosan. However, the incorporated oils modified the mechanical strengths, water vapor transmission rate, moisture content, and solubility of the chitosan film. Furthermore, chemical reaction took place between cinnamon oil and chitosan, whereas phase separation occurred between clove bud oil and chitosan.     

富啡酸对石灰性潮土中磷吸附-解吸及其对锌次级吸附-解吸的影响

通过吸附和解吸试验,研究了富啡酸（Fulvic acid,FA）对石灰性潮土中磷吸附一解吸的影响,并进行了吸附富啡酸和磷后对锌次级吸附一解吸的影响。结果表明：同时吸附不同磷和富啡酸后,土壤对磷的吸附量随磷初始浓度的增加而增加,而随富啡酸吸附初始浓度的增加而降低;石灰性潮土磷等温吸附曲线用Langumir方程式描述时,土壤对磷的吸附反应常数K、最大吸附量Xm、最大缓冲容量KxXm均随富啡酸初始浓度的增加而降低;KNO_3、KOH、HCI对吸附磷的解吸量所占比例及磷的总解吸量均随富啡酸浓度的增加而增加。土壤对Zn^2＋的吸附率随磷和富啡酸吸附初始浓度的增加而降低;而其解吸率随磷和富啡酸吸附浓度的增加而增加,说明磷和富啡酸减少了土壤对Zn^2＋的吸附,且增加了其在土壤中的解吸量。所以,石灰性潮土中富啡酸提高了土壤中磷的有效性,而且磷和富啡酸提高石灰性土壤中锌的有效性。     

云南省野生花卉的开发利用与可持续发展

中国有着让世界为之惊叹的植物资源,云南省的野生花卉资源为中国的花卉产业提供了雄厚的资源后盾。云南省是中国乃至世界著名的"植物王国",具有近2万种的高等植物,几乎占了全国植物物种总数的50.00%。在这些植物中,野生观赏植物约有3000种,无论春夏秋冬,都总有鲜花绽放。不仅为云南省野生花卉资源的合理开发利用提供了重要条件,还能有效促使其与云南省蓬勃发展的花卉业相互融合。     

Chitin-induced dimerization activates a plant immune receptor

Pattern recognition receptors confer plant resistance to pathogen infection by recognizing the conserved pathogen-associated molecular patterns. The cell surface receptor chitin elicitor receptor kinase 1 of Arabidopsis (AtCERK1) directly binds chitin through its lysine motif (LysM)-containing ectodomain (AtCERK1-ECD) to activate immune responses. The crystal structure that we solved of an AtCERK1-ECD complexed with a chitin pentamer reveals that their interaction is primarily mediated by a LysM and three chitin residues. By acting as a bivalent ligand, a chitin octamer induces AtCERK1-ECD dimerization that is inhibited by shorter chitin oligomers. A mutation attenuating chitin-induced AtCERK1-ECD dimerization or formation of nonproductive AtCERK1 dimer by overexpression of AtCERK1-ECD compromises AtCERK1-mediated signaling in plant cells. Together, our data support the notion that chitin-induced AtCERK1 dimerization is critical for its activation.     

禾谷镰孢的产毒与致病性

小麦穗期接种禾谷镰孢FusariumgraminearumSchw . [有性态 :Gibberellazeae (Schw .)Petch]的 2个野生型菌株和12个产毒潜能不同的转化体菌株 ,发病盛期 (接种后 2 0d)调查病小穗率 ,并测定组织中脱氧雪腐镰刀菌烯醇 (DON)、15 乙酰脱氧雪腐镰刀菌烯醇 (15 ADON)和 3 乙酰脱氧雪腐镰刀菌烯醇 (3 ADON)等单端孢霉烯族毒素 (以下简称“单族毒素”)的含量。结果显示 ,菌株间致病力存在显著差异。强致病力的GZ36 39、C11 1和B4 1等菌株在病穗 (显症 )组织和穗颈组织中DON产量高 ,分别达 2 9～ 38μg·g-1和 2 6～ 6 0 μg·g-1(以干重计 ,以下同 ) ,15 ADON在穗颈组织中的积累量为 15～ 31μg·g-1,显著高于病穗组织中的积累量 (5～ 7μg·g-1) ;另一强致病力菌株JF 12除在病穗和穗颈组织中产生大量DON (分别为 4 4和 5 5 μg·g-1)外 ,还产生大量的 3 ADON (分别为 17和 4 6 μg·g-1) ;不产毒的GZT 4 0 (产毒基因Tri5失活 ,Tri5 -)菌株接种后 ,仅在接种小花颖片上产生鸟眼状坏死斑点 ,病斑不扩展至其他小花和小穗 ,穗组织中也没有任何单族毒素积累 ;所有处理接种穗的健康 (无症 )组织中均没有明显的单族毒素积累 (<0 5 μg·g-1)。相关性分析表明 ,菌株的致病力与穗颈组织中DON和 15 ADON的积累量成     

KT与NAA对马铃薯组培苗生长的影响

培养其中KT与NAA含量对马铃薯组培苗生长有很大的影响,试验找出了马铃薯组培苗扦插成活率低的原因,并得到了最佳KT和NAA组合。当KT为0．4mg/L、NAA为0．04mg/L时,组培苗鲜重、根重、根数、腋芽发生数及腋芽发生百分比分别为2．89g/10株、0．52g/10株、7．6个／株、2．7个／株、76．4％,扦插成活率达到84．8％,比试验前提高了40．6％。