苹果梨果实采后呼吸和乙烯释放规律

苹果梨果实在9月20日采收后，在20℃下的呼吸强度逐渐降低，在果实衰败时有一个“呼吸峰”，而乙烯释放量则呈峰型变化，用外源乙烯处理苹果梨果实，证明该果实的呼吸属于非跃变型。     

李果实成熟软化过程中生理特性及乙烯合成变化的研究

以乙烯合成途径为线索,研究李(Prunus domestica L.)果实成熟软化过程中硬度、可溶性固形物、可滴定酸、乙烯释放量、氨基环丙烷羧酸(ACC)和丙二酰氨基环丙烷羧酸(MACC)含量以及ACC合成酶(ACS)和ACC氧化酶(ACO)活性等指标的变化,探讨乙烯在李果实成熟软化中的作用。结果表明:李果实成熟软化过程中,硬度和可滴定酸的含量逐渐降低,可溶性固形物含量增加。李果实成熟期的软化启动阶段,乙烯释放量、ACC含量、ACS和ACO活性增强缓慢,此时乙烯释放量也比较低,ACS和ACO的活性都受到一定程度的抑制,在成熟过程中三者高峰值同时出现在软化后期。证明李果实成熟期的软化启动阶段,乙烯并非是软化启动因子,可能还存在其他的启动相关因子。     

Supported iron nanoparticles as catalysts for sustainable production of lower olefins

Lower olefins are key building blocks for the manufacture of plastics, cosmetics, and drugs. Traditionally, olefins with two to four carbons are produced by steam cracking of crude oil-derived naphtha, but there is a pressing need for alternative feedstocks and processes in view of supply limitations and of environmental issues. Although the Fischer-Tropsch synthesis has long offered a means to convert coal, biomass, and natural gas into hydrocarbon derivatives through the intermediacy of synthesis gas (a mixture of molecular hydrogen and carbon monoxide), selectivity toward lower olefins tends to be low. We report on the conversion of synthesis gas to C(2) through C(4) olefins with selectivity up to 60 weight percent, using catalysts that constitute iron nanoparticles (promoted by sulfur plus sodium) homogeneously dispersed on weakly interactive α-alumina or carbon nanofiber supports.     

2,4,5-trichlorophenoxyacetic Acid: effect on ethylene production by fruits and leaves of fig tree

Production of ethylene by fruits and leaves of the fig tree was stimulated by the application of 2,4,5 trichlorophenoxyacetic acid (20 parts per million) to levels that apparently were responsible for hastened matura tion of fruit, epinasty, and senescence of leaves.     

气调对猕猴桃果实采后乙烯生成的效应及其机制

气调贮藏条件下猕猴桃果实成熟延缓,组织内乙烯含量及乙烯生成速率明显低于对照,气调 处理抑制乙烯生成的效应主要通过抑制ＡＣＣ合成实现,也抑制ＡＣＣ氧化酶活性,降低ＡＣＯ／ＡＣＣ＋ ＭＡＣＣ）比值, ＡＣＣ含量是猕猴桃果实采后乙烯生成的限制因子。气调条件下果实组织内乙烯含量、 ＡＣＣ含量及ＡＣＣ氧化酶活性变化出现交替升降现象。     

牡丹开花和衰老期间乙烯及脂质过氧化的研究

研究了牡丹在自然开花和衰老过程中乙烯和乙烷的产生,及脂质过氧化水平的变化。结果表明,显色后花径和花质量迅速增加,盛开达到最大值;乙烯和乙烷释放量有明显的跃变高峰,且乙烷高峰出现的早;ＳＯＤ 活性在盛花后迅速下降,Ｏ－·２ 产生速率和ＭＤＡ 含量迅速上升。并且认为乙烯的大量产生和脂质过氧化的增加是牡丹花衰老的重要生理原因     

纳米铁氧化物强化牛粪厌氧发酵产甲烷

为探究金属添加剂对牛粪厌氧发酵产甲烷过程的影响,提升牛粪厌氧发酵效率,本研究以纳米铁氧化物（Iron oxide nanoparticle,INP）为典型金属添加剂,比较了添加INP的反应器和从未添加INP的对照反应器中日产甲烷量、总挥发性酸、纤维素和半纤维素等的变化,并进一步探究INP添加对微生物群落和关键酶活性的影响。结果显示,INP添加促进纤维素水解并有利于挥发性脂肪酸的降解,从而促进产甲烷过程。连续反应器每日添加625 mg∙L^-1 INP时日甲烷产量达到173.4 mL∙g^-1∙d^-1,比对照组提高了38.3%;即使反应器停止添加INP,与对照组相比日产甲烷量依然显著提高（P＜0.05）。16S rRNA分析表明,INP添加富集了乙酸氧化菌Mesotoga和嗜氢产甲烷菌Methanoculleus这一对协同互营菌。宏基因组分析表明,INP添加显著促进嗜乙酸产甲烷途径和嗜氢产甲烷途径相关酶的活性,尤其提高了甲烷合成关键酶-甲基辅酶M还原酶（EC 2.8.4.1）的活性（P<0.05）,这是产甲烷效能提升的主要原因。综上,INP添加剂的施用有利于牛粪厌氧发酵产甲烷,从而提升畜禽粪污能源化利用效率。     

冬枣酒软过程中呼吸强度和乙烯代谢的变化及1-MCP的处理效应

以半红果期的冬枣为材料 ,装入打孔的农膜袋中贮藏于 ( 2 0± 2 )℃和 ( 4± 0 5 )℃ ,研究其果实酒软的规律。结果表明 :随着贮藏时间的延长 ,果实乙醇含量持续上升 ,当乙醇含量达到 0 1%时 ,果实明显酒软 ;酒软过程中无呼吸高峰和乙烯释放高峰出现 ;果实的呼吸作用与乙醇积累呈正相关 ;降低温度可以抑制其呼吸强度 ,减缓酒软进程 ;室温下 1 0 0 μL·L-11 MCP密闭处理冬枣 12h ,明显抑制了乙烯释放量 ,但对呼吸作用的抑制效果不明显。冬枣贮藏期的酒软受呼吸代谢和乙烯代谢的双重调节 ,适宜的 1 MCP处理可以延缓酒软的发生     

圆黄、黄金等5个砂梨品种果实呼吸和乙烯释放规律

以秋子梨系统京白梨和白梨系统锦丰梨果实为对照,采用500 μl/L外源乙烯和1.0 μl/L 1-MCP处理,研究圆黄、黄金等5个砂梨品种在常温条件下的呼吸强度和乙烯释放规律变化.结果表明:新世纪、绿宝石和圆黄梨为非呼吸跃变型果实,采后常温呼吸强度乙烯释放量变化不大,外源乙烯处理不能促进呼吸乙烯,1-MCP处理可抑制呼吸强度,但不减少乙烯释放量;黄冠梨和黄金梨具有一定程度呼吸跃变,外源乙烯处理增加果实呼吸乙烯峰,1-MCP处理不能减少乙烯释放量;圆黄梨呼吸乙烯呈双峰型,黄金梨呈波浪型.整体而言,砂梨采后常温呼吸和乙烯整体变化不大,秋子梨(京白)呈先明显上升后下降趋势,而白梨(锦丰)则逐渐升高.     

不同催化剂条件下毛竹材液化反应动力学研究

为了筛选出高效液化竹材催化剂,达到竹材温和条件下液化,该文利用等温差示热量扫描曲线方法,分析了不同催化剂（KCl和K2 CO3）对毛竹材液化剂苯酚液化反应的影响。在20～300℃温度范围内,运用Kissinger方程在不同的升温速率（5、10、15和20℃/min）下进行动力学研究。结果表明:竹材液化反应是吸热反应;随着升温速率的增加,特征液化温度向高温方向移动;不同催化剂（K2 CO3、KCl、无催化剂）条件下竹材液化反应表观活化能依次是45.95、59.99、58.00 kJ/mol,可见K2 CO3适合做竹材液化的催化剂。由外推法得出竹材液化反应最佳工艺为:催化剂为K2 CO3,初始液化温度为691℃,液化峰高温度为97.3℃,液化峰终温度为111.9℃。      

乙烯处理对树莓果实呼吸速率及乙烯合成代谢的影响

采集不同成熟期(绿果期、白果期、着色期、成熟期、过熟期)"哈瑞太兹"树莓果实,并利用乙烯利及乙烯抑制剂1-MCP处理白果期果实,测定上述果实不同部位(整果、小核果和花托)乙烯生成速率、呼吸速率、ACC合成酶(ACS)和ACC氧化酶(ACO)活性及RiACS1和RiACO1基因相对表达量变化。结果表明,花托是树莓果实中产生乙烯的主要部位,果实食用部分小核果乙烯生成和呼吸速率在果实发育期间变化平稳,同时结合树莓果实采后无后熟、常温贮存后易腐烂的特性,推测树莓应属于非跃变型果实。乙烯利处理促进树莓果实提前着色,整果、小核果和花托乙烯生成速率短时内增加,ABA含量显著增加,提高ACS和ACO酶活性及RiACS1和RiACO1基因转录水平,而1-MCP抑制此过程。乙烯利处理对呼吸速率影响较小,但1-MCP处理显著抑制小核果和花托中的呼吸速率。     

Powering fuel cells with CO via aqueous polyoxometalates and gold catalysts

Electricity was produced by catalytic oxidation of carbon monoxide (CO) by using gold catalysts at room temperature. The observed rates are faster than conventional processes operating at 500 kelvin or higher for the conversion of CO with water to produce hydrogen and carbon dioxide through the water-gas shift (WGS). By eliminating the WGS reaction, we remove the need to transport and vaporize liquid water in the production of energy for portable applications. This process can use CO-containing gas streams from the catalytic reforming of hydrocarbons to produce an aqueous solution of reduced polyoxometalate compounds that can be used to generate power. The reduced polyoxometalate can be reoxidized in fuel cells that contain simple carbon anodes.     

松香催化裂解及裂解产物组成

以活性白土、磷钨酸等为催化剂进行了松香催化裂解试验,并以活性白土为催化剂进行松香裂解反应条件及裂解产物组成的研究。结果表明：活性白土和磷钨酸的催化性能较强,反应2 h后可使松香酸值分别降至1.20 mg·g^－1和2.07 mg·g^－1;活性白土催化裂解松香的工艺条件为温度220 ～ 240 ℃、催化剂用量5.0% ～ 10.0%、反应时间1.0 h;在此反应条件下得到的裂解产物经气相色谱/质谱（GC/MS）分析表明是各种芳香类化合物的混合物,主要由萘、吲哚、吡啶和菲类等物质组成;松香裂解反应除了松香脱羧反应外,同时伴随着大量碳—碳键和碳—氢键的断裂和重排。图1表5参9     

果实裂果机理研究进展与展望

裂果现象在多种果实中存在,外界环境条件、果皮组织力学性能、果皮结构特点、矿质营养、遗传因素及栽培方式等与裂果密切相关,从水分、赤霉素、脱落酸、钙和细胞壁等5个方面综述了国内外与裂果的研究进展。果皮所受膨压受水分以及赤霉素和脱落酸含量的影响,果皮力学强度受钙和细胞壁组分的影响,果皮延伸性受细胞壁松弛基因的影响。过多的水分以及赤霉素和脱落酸含量变化会使果皮所受膨压增加,钙含量的降低以及细胞壁组分的变化使果皮的力学强度降低,细胞壁松弛基因表达量的降低使果皮延伸性减弱。当果皮所受膨压、果皮力学强度和果皮延伸性3个因素处于平衡时不发生裂果,但当果皮所受膨压增加、果皮力学强度和果皮延伸性降低时导致裂果发生。     

营养调控技术在融安滑皮金桔裂果防控上的应用研究

为了提高融安金桔进一步提高融安金桔品质,目前,我们在融安县建立了金桔种植示 范基地,示范基地采用了金桔营养调控技术进行管护,种植成果比较显著。本文讨论了示范基 地的建设和金桔的先进种植方法。     

SlGH9-15 regulates tomato fruit cracking with hormonal and abiotic stress responsiveness cis-elements

Fruit cracking occurs easily during the late period of fruit development when plants encounter an unsuitable environment, dramatically affecting fruit production and marketing. This study conducted the bulked segregant RNA-Seq (BSR) to identify the key regulatory gene of fruit cracking in tomatoes. BSR-Seq analysis illustrated that two regions associated with irregularly cracking were located on chromosomes 9 and 11, containing 127 candidate genes. Further, through differentially expression analysis and qRT-PCR in cracking-susceptible and cracking-resistant genotypes, the candidate gene SlGH9-15 (Solyc09g010210) with significantly differential expression levels was screened. Bioinformatics analysis of the GH9 gene family revealed that 20 SlGH9 genes were divided into three groups. The phylogenetic analysis showed that SlGH9-15 was closely related to cell wall construction-associated genes AtGH9B1, AtGH9B6, OsGH9B1, and OsGH9B3. The cis-acting elements analysis revealed that SlGH9-15 was activated by various hormones (ethylene and ABA) and abiotic stresses. The expression pattern indicated that 13 SlGH9 genes, especially SlGH9-15, were highly expressed in the cracking-susceptible genotype. Its expression level gradually increased during fruit development and achieved maximum value at the red ripe stage. Additionally, the cracking-susceptible tomato showed higher cellulase activity and lower cellulose content than the cracking-resistant tomato, particularly at the red ripe stage. This study identified SlGH9-15 as a key gene associated with fruit cracking in tomatoes for the first time and gives new insights for understanding the molecular mechanism and complex regulatory network of fruit cracking.     

Chemoselective hydrogenation of nitro compounds with supported gold catalysts

The selective reduction of a nitro group when other reducible functions are present is a difficult process that often requires stoichiometric amounts of reducing agents or, if H2 is used, the addition of soluble metals. Gold nanoparticles supported on TiO2 or Fe2O3 catalyzed the chemoselective hydrogenation of functionalized nitroarenes with H2 under mild reaction conditions that avoided the accumulation of hydroxylamines and their potential exothermic decomposition. These chemoselective hydrogenation gold catalysts also provide a previously unknown route for the synthesis of the industrially relevant cyclohexanone oxime from 1-nitro-1-cyclohexene.     

壳聚糖对采后黄花梨果实膜脂过氧化和乙烯生成的影响

以黄花梨果实为试材,测定了经壳聚糖涂膜处理的果实在常温贮藏过程中膜脂过氧化和乙烯生成的变化.结果表明:壳聚糖涂膜使果实SOD活性维持在较高水平,LOX活性较低,细胞膜稳定性增加、透性变小,MDA含量显著减少,乙烯释放跃变不很明显且较低.而对照处理的果实SOD活性很快下降,LOX活性初期和后期较高,乙烯释放量较大,并在采后第11日左右出现明显的跃变峰.     

猕猴桃果实后熟过程中乙烯生成和超氧物歧化酶及过氧化物酶的活性变化

以美味猕猴桃[Actinidia deliciosa(A.chev.)C.F.Liang et A.R.Ferguson]“布鲁诺”(Bruno)果实为试材,研究(20±1℃)后熟过程中乙烯生成、超氧物歧化酶(SOD)和过氧化物酶(POD)的活性变化。结果表明:猕猴桃果实具有典型的乙烯跃变峰,峰值出现在采后第11天左右;SOD活性变化与ACC含量变化呈显著正相关(r=0.6766~(?));过氧化物酶活性峰值于乙烯跃变峰之后出现。果实可溶性固型物(TSS)含量在整个后熟过程中呈持续上升趋势。SOD可能参与了猕猴桃果实的后熟调节,在乙烯生物合成过程中起重要作用;POD活性变化可以作为猕猴桃果实组织衰老的一个参数。