玉米中植酸代谢及其育种

植酸及其代谢中间体具有重要的生物学功能.禾谷科和油料作物的种子中积累了丰富的植酸.植酸既是一种抗营养因子,也是一种重要的健康因子.然而自植酸被发现至今,人们对于其在植物中的合成过程仍然知之甚少,对其生物学功能更是缺乏全面的了解.近年来,有关于植酸代谢及其功能分析的研究逐渐引起了人们的关注.在玉米(Zea mays)、水稻(Oryza sativa)、大豆(Glycine max)中,人们发展、分离了一系列的低植酸突变体,以期降低种子中的植酸含量,从而获得可用于生产的、能够增强动物磷和矿质营养利用效率并能降低环境污染的新品种.早期的研究发现,植物中植酸的合成途径有两条:依赖于磷脂酰的合成途径和不依赖于磷脂酰的合成途径.有证据表明,作物种子中植酸的积累主要是不依赖于磷脂酰途径的贡献.玉米是中国主要的粮食和饲料作物,关注玉米中植酸代谢和育种的相关研究将有利于动物营养强化以及人类和环境健康.本文综述了植酸的生物学功能以及植酸代谢研究现状,分析并总结了植酸的代谢通路,评述了植酸在玉米中代谢的研究成果,为今后植酸代谢相关的研究提供参考.     

磷高效利用型转植酸酶基因玉米

植酸又称肌醇六磷酸,是植物中磷的主要储存形式,也是土壤有机磷的主要存在形式。动植物利用植酸磷,需要利用植酸酶将其降解为肌醇和磷酸。但自然条件下,植物的植酸酶表达量较低,不能提供足量的植酸酶活力。据此,我国科学家培育出磷高效利用型转黑曲霉源植酸酶基因phyA2玉米,该玉米不但可以通过根系向土壤中分泌大量的植酸酶,提高植株对土壤有机磷的利用效率;还可以在玉米的籽粒中积累丰富的植酸酶(干物质植酸酶活力高达7032U·kg~(-1)),提高动物对饲料磷及植酸螯合的钙、镁、锌、铜等微量元素的利用效率。     

多环芳烃污染土壤的微生物与植物联合修复研究进展

本文综述了多环芳烃(PAHs)污染土壤中微生物降解途径、机理及生物反应器的应用,并从植物修复角度,进一步阐述了与微生物联合作用促进污染土壤中PAHs降解的途径、机理及其应用。提出了利用微生物共代谢降解及其与植物联合修复PAHs污染土壤环境的生物修复技术未来研究课题。     

萌芽对大豆中营养及抗营养因子的影响研究

大豆是营养极其丰富的植物性食品,在其萌芽过程中,维生素C、GABA、大豆异黄酮等营养物质的含量增长,脂肪酸氧化酶、植酸、植物凝集素等抗营养因子含量下降,因此萌芽可作为改善大豆营养组份、提高大豆及其制品营养价值的重要手段。本文综述了大豆萌芽过程中重要营养因子、抗营养因子及生物活性物质的变化规律,并对大豆萌芽的应用及意义进行了展望,以期明确大豆萌芽过程中物质变化规律,为今后科学研究及应用奠定基础。     

钾在植物抗病性中的作用及机理的研究进展

本文对近些年来有关钾营养与植物病害关系的研究进行综述。主要从钾对酚代谢、碳、氮代谢及其活性氧代谢调控的角度,评述钾素营养提高植物抗病性的机理;同时讨论了钾肥的施用方式、钾肥形态、施用量、土壤本身钾素状况等共同影响钾素对植物的抗病性及其可能机理。最后提出这一研究领域存在的若干问题。     

离子束注入技术选育胶质芽孢杆菌KNP414的解磷突变菌株

利用离子束注入对胶质芽孢杆菌KNP414进行诱变,获得可降解植酸的突变菌株。离子束注入效应表明,菌株KNP414的存活率显著受离子束剂量及菌体荚膜的影响,但与所研究的离子种类及其能量没有相关性。经离子束N+(20keV,5×1015~5×1016ions cm-2)诱变后,筛选到14个植酸降解突变株,它们对植酸的降解率为15%~35%。其中的3个突变株(KNP414-04,KNP414-05,KNP414-12)分解矿物磷和钾的能力也明显提高,分别增加14.7%~27.5%和16.2%~26.4%。在优化培养基中,突变菌株KNP414-12对植酸的降解率达到57.3%,且在连续培养及保藏过程中保持稳定。植酸降解突变株KNP414-12的成功选育表明离子束为胶质芽孢杆菌的性状改良提供了有效途径。     

十字花科植物黑斑病的研究进展

十字花科植物黑斑病是由死体营养型致病菌链格孢属(Alternaria spp.)真菌侵染引起的重要病害之一。链格孢菌侵染植物的过程,首先通过释放毒素诱导侵染处植物细胞的程序性死亡,再通过细胞壁降解酶分解死亡的细胞。同时,植物也会通过激发先天性免疫反应,调节植物内源激素和植物抗毒素等分子抵御病菌的侵染。本文重点综述了链格孢菌侵染十字花科植物过程中,双方在基因组(致病和抗病基因)、转录组(调控因子)、代谢组(毒素和抗毒素)和蛋白组(酶类)等方面的相关变化及其作用机制,以期为培育抗黑斑病的十字花科蔬菜提供有价值的参考。     

~(14)C-久效磷涂抹棉苗茎秆后药剂的吸收、分布和代谢

本文采用放射性同位素示踪技术研究了久效磷在棉苗体内的吸收,分布和代谢。 试验结果表明:用久效磷涂抹茎秆后,药剂可以在植物体内部迅速向上和向下传输。在涂抹剂量相同的情况下,双侧涂抹比单侧涂抹效果更好。 久效磷在棉苗体内降解形成一个R_f值为0.11的代谢产物,它可能是N-羟甲基代谢物与植物体内的糖相结合形成的水溶性轭合物。久效磷在棉苗体内代谢速度较慢,给药处理6天后,棉苗的萃取液中69.8％的放射性物质是以母体化合物的形式存在。     

低植酸作物的研究进展及展望

对植酸的含量与贮存形式及其生理功能、低植酸作物的营养功能、低植酸突变体作物的培育与研究、低植酸突变的分子遗传学特性及其可能机理进行了综述 ,并对今后的工作提出了展望。     

双功能域β- 折叠桶植酸酶提高土壤有效磷含量研究

农业生产中过度使用无机磷肥引发了土壤板结等一系列问题,因此有必要寻找一种替代的可持续的磷肥来源。土壤有机磷主要以植酸的形式存在,植物不能直接吸收和利用。植酸水解释放植酸磷可提供一个生态友好型的解决方案。通过向土壤中添加来自Bacillus sp.HJB17 的双功能域β- 折叠桶植酸酶(phyHT),研究其在土壤中的稳定性,探究phyHT 提高土壤有效磷含量、改善土壤理化性质以及促进植物生长的作用效果。结果显示,在湿润土壤中,土壤微生物对phyHT 影响很小,phyHT 可在较宽的温度(20 ～ 40℃)和pH 值(6.0 ～ 9.0)范围内稳定存在12 h 并发挥高效催化功能。外源性添加phyHT 后:(1)土壤植酸含量减少了17.00%,有效磷含量增加了22.52%;(2)土壤pH 下降,电导率上升,CaCO3 含量降低了3.55 个百分点,土壤有机质、铵态氮和速效钾含量分别增加了10.54%、18.38% 和27.49%;(3)小麦幼苗生长长度、干物质积累量以及芽、根部组织全磷含量均显著增加。因此,外源性添加phyHT 能够促进土壤植酸水解,增加土壤有效磷含量,提高土壤磷素有效性,同时,在一定程度上改善土壤理化性质,促进植物生长。     

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,     

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.     

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.     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.     

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,     

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,     

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.