LED红蓝弱光照射保持樱桃番茄冷库贮藏品质

为了探究单色光对番茄冷藏过程中品质的影响,开发樱桃番茄保鲜新技术,以绿熟期樱桃番茄(Lycopersicon esculentum Mill.)为试材,在4℃条件下分别采用发光二极管(LED,light emitting diode)红蓝单色弱光(30 lx)持续照射,研究LED红蓝单色弱光对樱桃番茄采后贮藏过程中感官和主要营养品质指标的影响。结果表明:研制的LED试验装置稳定可靠,红蓝单色光的发射光谱稳定,不因光照强度的变化而发生偏移。贮藏10 d以后LED红蓝光处理的樱桃番茄感官品质显著优于无光对照(P0.05),且LED红光处理好于蓝光处理(P0.05)。LED蓝光照射能较好地保持樱桃番茄维生素C含量(P0.05),但LED红光照射不利于维生素C含量的保持。LED红蓝单色弱光照射有利于促进樱桃番茄早期贮藏过程中的还原糖和可溶性总糖积累,显著抑制贮藏后期糖含量的下降(P0.05)。LED红蓝单色弱光照射处理还能显著延缓樱桃番茄贮藏过程中可溶性固形物下降(P0.05),提高樱桃番茄果实可滴定酸的含量,其中LED红光处理显著高于蓝光处理(P0.05)。贮藏20 d时,红光照射可显著促进番茄红素的合成,但贮藏过程中LED蓝光照射与对照差异不显著(P0.05)。综合来看,与对照(CK)相比,LED红蓝弱光(30 lx)照射有利于樱桃番茄4℃贮藏过程中感官和营养价值的保持,其中LED红色弱光照射处理效果较好。作为一种简便可行的物理保鲜方法,LED红蓝弱光持续照射处理在樱桃番茄采后营养品质调控方面具有应用潜力。     

“喷施宝”茶叶专用肥对铁观音茶园的影响初探

试验初步探讨了喷施宝茶叶专用肥对茶园产量,茶树叶片稀土含量、农残,茶叶品质及其成分的影响。结果表明:喷施加入1500倍喷施宝茶叶专用肥的铁观音茶园产量优于喷施清水的对照组;喷施加入1500倍喷施宝茶叶专用肥+"喷施0.05%联苯菊酯、0.3%毒死蜱、0.3%虫螨腈"的铁观音茶园鲜叶的3种农残含量相比对照组清水喷施有降解作用。浇灌500倍喷施宝茶叶专用肥+叶面喷施1500倍喷施宝茶叶专用肥铁观音毛茶,感官审评中色泽砂绿油润,清香;但滋味略有苦涩味;鲜叶及毛茶品质成分相比喷施清水的对照组咖啡碱含量有所降低,EGCG含量有显著的提高。     

不同堆闷程度对六堡茶毛茶香气的影响研究

采用顶空固相微萃取方法(HS—SPME)结合气质联用技术(GC—MS),探索六堡茶初制过程中不同堆闷程度处理对毛茶香气组成和感官品质的影响,结果表明:不同堆闷程度处理的毛茶在香气组成和感官表现上存在明显差异,重度堆闷处理的六堡茶毛茶在陈香物质积累最多,在感官表现上最优。本研究结果可为六堡茶的标准化生产提供技术支撑。     

LED光质萎凋对绿茶品质的影响研究

采用1芽1叶、1芽2叶鲜叶为原料,以自然光萎凋为对照,分别采用红、橙、黄、绿、蓝光质LED灯单色光照射萎凋,研究了不同LED单色光质在萎凋过程中对主要内含成分含量变化及绿毛茶品质的影响。结果表明:与对照(自然光萎凋)相比,LED光质萎凋有利于茶叶水浸出物含量的增加;萎凋叶茶多酚含量均随时间增加呈下降的趋势,其下降最多的是蓝光萎凋,其含量比鲜叶减少3.59%、比对照减少1.20%;红光萎凋的氨基酸含量最高,比对照增加0.12%。;萎凋可增加可溶性糖含量,自然萎凋的萎凋叶可溶性糖含量最高,黄光次之;几种方式萎凋叶咖啡碱含量相对稳定;经橙光照射萎凋的茶鲜叶所制绿毛茶综合得分最高为89.65,其次是绿光。从各项评分来看,经橙光、绿光照射萎凋后有利于绿茶汤色、香气及滋味的提升。     

摇青工艺对工夫红茶品质影响初探

为制作出品质更为优异的红茶,实验将摇青工艺加入到传统红茶制作工艺中。结果表明:摇青处理为1-2-5 min的茶样香气花果香较浓且香气较持久、汤色橙黄明亮、滋味浓醇,甘甜,品质较为优异。生化成分测定结果,茶多酚含量均明显大于对照;咖啡碱含量虽为1-2-5 minCK4-7-9 min2-5-7 min3-6-8 min,但实验过程中整体变化量不大;氨基酸含量为1-2-5 min3-6-8 min4-7-9min2-5-7 minCK;水浸出物含量为处理1-2-5 min3-6-8 min4-7-9 min2-5-7 minCK。通过感官与生化成分的综合分析,认为摇青处理为1-2-5 min工艺参数制得的红茶品质较为优异。     

不同红光远红光配比对冰草生长发育、光合特性及品质的影响

为探明人工光植物工厂中红光远红光配比对水培冰草产量和品质的影响,本研究在光合有效辐射强度200 μmol·m-2·s-1的条件下,以白光LED作为CK(R/FR=5.5),在CK基础上添加不同强度远红光,分别设置FR1(R/FR=1.2)和FR2(R/FR=0.8),研究不同光质组合处理下冰草的生长发育、光合特性及营养...     

荧光粉激发型远红光LED植物灯对番茄生长的影响研究

为探究远红光对植物生长的影响,采用“燃烧法+高温二次烧结”的方法制备了ZnGa₂O₄:Cr³⁺,Ge⁴⁺,Li⁺(ZGO:Cr³⁺,Ge⁴⁺,Li⁺)荧光粉,将自制的荧光粉材料涂覆在410 nm的蓝紫光LED芯片上,封装成发射主峰位于710 nm左右的LED远红光器件,并进一步组装成LED植物生长灯作为直接光源。以番茄(Solanum lycopersicum)品种红矮生为试材,白光(W)为对照(CK),设置3个处理:T1:红蓝组合光(1R1B)加远红光(光质比为3:1);T2:红蓝组合光(1R1B);T3:白光加远红光(光质比为3:1),研究红蓝组合光(1R1B)和远红光对番茄生理周期、农艺性状、光合色素和番茄果实主要品质的影响。结果表明,与CK相比,T1处理可显著缩短番茄生理周期,T1、T2和T3处理对番茄农艺性状中的株高有抑制作用。添加远红光降低了光合色素的含量,但提高了番茄果实中可溶性糖、番茄红素和维生素C的含量,特别是在红蓝组合光与远红光的共同作用下,可溶性糖含量提高效果最明显,达到CK的3.3倍。添加远红光能够促进维生素C和番茄红素含量增加;红蓝组合光则有利于番茄红素的积累。综上,采用ZGO:Cr³⁺,Ge⁴⁺,Li⁺远红光荧光粉激发型LED植物灯能调控番茄开花时间,缩短其生理周期,提高番茄果实品质。本研究结果为提高番茄以及其他园艺作物的品质提供了一种新的光照手段,具有广阔的应用前景。     

海藻提取物与养分配施对葡萄果实品质及养分吸收的影响

研究海藻提取与养分配施对葡萄果实品质和养分吸收的影响,以“阳光玫瑰”葡萄为试验材料,设置5个处理:NPK 水溶肥(CK)、0.375% 海藻提取物与NPK 水溶肥配施(T1)、0.75% 海藻提取物与NPK 水溶肥配施(T2)、1.5% 海藻提取物与NPK 水溶肥配施(T3)和3% 海藻提取物与NPK 水溶肥配施(T4)。结果表明,海藻提取物与NPK 水溶肥配施能增加葡萄单穗重、产量和SPAD 值,T1、T2 和T3 处理果实可溶性糖和糖酸比含量分别较CK 提高77.98%、17.51%、1.42% 和69.45%、35.65%、11.45%,T4 处理降低果实可溶性糖和糖酸比含量。T2 处理果实磷含量和叶片钾含量最高,较CK 分别显著提高26.97% 和47.87%。此外,海藻提取物与NPK 水溶肥配施均增加果实香气化合物种类,其中,T2 处理果实香气化合物种类数最高。主成分分析中,T2 处理的葡萄果实产量、品质、养分吸收和果实香气物质影响中得分最高。综合分析,海藻提取物与养分一定比例配施能够提高葡萄产量、改善品质、促进养分吸收以及增加果实香气物质种类和相对含量,其中,0.75% 海藻提取物与NPK 水溶肥配施处理效果更佳。     

采收前LED红蓝光连续照射对水培生菜品质的提升作用

在环境可控的植物工厂内,以水培"意大利耐抽薹"生菜(Lactuca sativa L.)为试验材料,于采收前72h,用不同光照强度的LED红蓝光进行连续照射(CL),研究照射对水培生菜叶片C、N、P、K、Ca、Mg、Fe、Mg、Cu和Zn十种营养元素含量的影响。生菜定植后在6:00-22:00光期下连续培养17d,培养阶段红蓝光光强均为150μmol·m~(-2)·s~(-1),从定植后第18天开始进行连续72h不同光强的CL处理。试验设置CL光强分别为100、150、200、300和500μmol·m~(-2)·s~(-1)(用CL100、CL150、CL200、CL300和CL500表示),并设置全生长期光强为150μmol·m~(-2)·s~(-1)的处理作为对照(CK),其光期为6:00-22:00。结果表明:CK处理下,生菜干物质中P、K、Ca、Mg的含量最高。采收前最后72h用LED红蓝光连续照射后,生菜干物质中C的含量随CL光强的增加而增加,CL100处理下,N和Mn的含量最高,CL300时,Cu的含量最高,CL对Zn的含量无显著影响。生菜干物质中C、N、Fe和Zn的总量在CL500处理下最高;CL200处理下,P和K的总量最高;CL300处理下,Mg和Cu的总量最高。CL光强对Ca和Mg的总量无显著影响。因此,实际生产中可以通过采收前集中连续LED红蓝光照射,达到提高生菜品质或生产富含某种营养元素的功能性蔬菜的目的。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.     

Electron donor and pH relationships for biologically enhanced dissolution of chlorinated solvent DNAPL in groundwater

Biologically enhanced dissolution offers a method to speed removal of chlorinated solvent dense non-aqueous-phase liquid (DNAPL) sources such as tetrachloroethene (PCE) and trichoroethene (TCE) from aquifers. Bioremediation is accomplished by adding an electron donor to the source zone where fermentation to intermediates leading to acetic acid and hydrogen results. The hydrogen and possibly acetic acid are used by dehalogenating bacteria to convert PCE and TCE to ethene and hydrochloric acid. Reductive dehalogenation is thus an acid forming process, and sufficient alkalinity must be present to maintain a near neutral pH. The bicarbonate alkalinity required to maintain pH above 6.5 is a function of the electron donor: 800 mg/L of bicarbonate alkalinity is sufficient to achieve about 1.2 mM TCE dechlorination with glucose, 1.7 mM with lactate, and a much higher 3.3 mM with formate. Laboratory studies indicate that in mixed culture, formate can be used as an electron donor for complete conversion to ethene, contrary to pure cultures studies indicating it cannot. Various strategies can be used to add electron donor to an aquifer for DNAPL dehalogenation while minimizing pH problems and excessive electron donor usage, including use of injection-extraction wells, dual recirculation wells, and nested injection-extraction wells.     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Increase in auxiliary photoprotective photosynthetic pigments in wheat seedlings induced by Azospirillum brasilense

Inoculation of wheat seedlings with the plant growth-promoting bacterium Azospirillum brasilense Cd was immobilized in alginate microbeads and, without applying any stress, significantly increased the quantity of several photosynthetic pigments, such as chlorophyll a, chlorophyll b, and the auxiliary photoprotective pigments violaxanthin, zeaxanthin, antheroxanthin, lutein, neoxanthin, and β-carotene. This resulted in greener plants with no apparent visible stress. After monitoring the quantity of photosynthetic pigments for 4 weeks, we observed that inoculated plants had higher quantities of pigments in shoot and stem. The greatest difference in the quantity of all pigments between inoculated and noninoculated plants occurred in the first week of growth. Regardless of treatment, the quantity of pigments in stems was three to four times less than the quantity of these pigments in shoots. Application of Azospirillum, either as liquid inoculant or as alginate microbeads, did not alter the positive effect of the bacteria on pigment production or the positive response of the plants towards A. brasilense Cd inoculation.     

In-situ enrichment and analysis of atrazine-degrading microbial communities using atrazine-containing porous beads

We examined the community composition of microbes that colonized atrazine-containing beads buried in agricultural soils that differed in atrazine treatment history. Bacterial abundance was 5-40-fold greater in atrazine-fortified beads. In beads containing 20 mg atrazine kg⁻¹ buried in soil with a history of atrazine application (conditioned soil), the abundance of Actinobacteria increased approximately 80-fold whereas in control soil, Actinobacteria were enriched only 10-fold and the gamma-Proteobacteria and Planctomycetes increased by 60- and 25-fold, respectively. The gamma-Proteobacteria were enriched by 120- and 230-fold in beads containing 200 mg atrazine kg⁻¹ in conditioned and control soil, respectively. The results demonstrate that BioSep^® beads are a suitable matrix for recruiting a diverse subset of the bacterial community involved in atrazine degradation.