基于CASA模型的区域冬小麦生物量遥感估算

该文对原始CASA(carnegie-ames-stanford-approach)模型中归一化植被指数(normalized difference vegetation index,NDVI)最值提取方法及光合有效辐射吸收比(fraction of absorbed photosynthetically active radiation,FPAR)的算法进行了深入分析,并通过综合分析大量国内外文献,更加科学合理的确定了最大光能利用率的取值,最终确立了适合该研究区的CASA模型。该文以河北省邯郸市3个县域冬小麦为研究对象,以HJ-1A/B星遥感数据产品为数据支撑,采用CASA模型对研究区2014年冬小麦生物量进行了估算和精度验证,结果表明:研究区冬小麦生物量平均值为1 485 g/m~2,50%以上区域在1 500~2 000 g/m~2之间。冬小麦实测生物量与预测生物量相关性达到显著水平,R~2为0.811 5。经过50组数据分析对比,平均相对误差为2.13%,其中,最大值为11.54%,最小值为0.33%;平均预测生物量为1 807.54 g/m~2,与平均实测生物量1 720.74 g/m~2相比,绝对误差为86.80 g/m~2,为估算区域冬小麦产量提供理论支撑。     

玉米/大豆间作条件下作物生物量积累模型

通过不同间作比例的玉米/大豆间作试验,建立了基于辐射截获与利用的玉米/大豆间作群体生长和产量的模拟模型。作物总生物量和产量为光合有效辐射(PAR)、辐射截获率(F)以及辐射利用效率(RUE)的函数,根据太阳辐射(SR)与PAR的比例可估算PAR,采用Keating和Carberry建立的公式计算F值,利用生长度日(GDD)确定作物的出苗、开花与成熟时期。模拟结果表明模型能够较为准确地模拟水分充足条件下间作群体的总生物量和产量。     

MODIS数据辅助的GF-1影像晴空光合有效辐射反演

面向农作物产量监测对中高分辨率遥感数据光合有效辐射(photosynthetically available radiation,PAR)反演的实际需求,该文选择山东省禹城市2014年1月至2014年12月共13景GF-1/WFV卫星影像作为数据源,基于中分辨率成像光谱仪(moderate-resolution imaging spectroradiometer,MODIS)地表反射率产品作为辅助数据源,开发了适于业务运行的WFV数据气溶胶光学厚度(aerosol optical depth,AOD)及PAR的反演算法。算法核心是采用6S(second simulation of satellite signal in the solar spectrum)大气辐射传输模型,建立包括AOD在内的大气参数与查找表(look-up table,LUT),结合大气顶层太阳入射辐照度及卫星入瞳处辐射亮度值反演地表反射率数据,通过与WFV蓝光波段地表反射率数据对比获取大气参数。通过反演的大气参数计算400~700 nm连续光谱区间的PAR值,并建立WFV数据离散红、绿、蓝光波段与连续光谱区间PAR的转换系数,实现WFV数据PAR的反演。其中,WFV蓝光波段反射率数据与MODIS地表反射率数据关系、离散到连续谱段PAR的关系可以从美国地质勘探局(United States Geological Survey,USGS)提供的典型地物波谱库数据理论计算获取。利用中国生态系统研究网络(chinese ecosystem research network,CERN)禹城站地面观测值进行验证结果表明,该文提出的算法总体精度达到92.63%,平均绝对误差为14.56 W/m~2,平均相对误差7.37%,具有业务应用的潜力。     

基于净初级生产力的关中--天水经济区耕地利用分区研究

耕地净初级生产力(NPP)值越大说明耕地有机生物量越高,其对粮食作物的最终产量起关键作用,因此,研究NPP的变化可为解决粮食安全问题提供重要依据。功能分区是保证土地可持续利用的常用手段,将不同耕地利用模式布局在不同行政区域,可作为地区政府通过管理手段提高产能利用率的有效参照。利用2001—2009年遥感数据,使用遥感估算NPP作为耕地作物生物量代替传统粮食统计数据,通过神经网络算法对关中天水经济区(关天经济区)耕地利用模式进行分区并利用小波神经网络模型对各区的NPP进行预测,得出:(1)关天经济区耕地NPP估算量除2001年外,总量保持在1 600万t,这与粮食统计数据之间的波动规律差异较大,分区中使用NPP数据分区比使用统计数据普适性更强。(2)关天经济区中部和渭河谷地的区县应作为关天经济区农业重点发展地区,率先对其进行精细农业与产业化经营试点的布局。(3)小波神经网络预测显示后6年(2010—2015年)中单位面积NPP上升为主要趋势。该结果证实了在农业作物生物总量短期内难以大幅提高的情况下,在管理上提升农作物能量利用效率是当下缓解耕地安全问题的最有效途径。     

扁桃-冬小麦间作系统树冠截光程度对小麦产量和灌浆期光合特性的影响

为探明果粮间作模式下树冠遮阴对间作冬小麦灌浆期光合特性和产量的影响,为新疆南疆果粮间作模式的选择和优化提供理论依据,本研究以扁桃-冬小麦间作模式为研究对象,设置重度遮阴和轻度遮阴2个处理,以单作小麦为对照,对间作区域光合有效辐射(PAR)、小麦产量及灌浆期叶片光合色素和可溶性蛋白含量、光响应曲线、荧光动力学参数、群体光合速率进行测定。结果表明:间作区域遮阴程度受树冠结构和间作区域距树体距离共同影响,主干分层形扁桃(重度遮阴)近冠和远冠间作区域小麦灌浆期PAR日均值为自然光强的18.61%和25.90%,小冠圆头形扁桃(轻度遮阴)对应值为56.00%和64.53%。与扁桃间作导致小麦旗叶Chla+b含量和Chla/b比值降低; PAR日均值≤56.00%自然光时,小麦旗叶可溶性蛋白质含量显著降低; PAR日均值≤25.90%自然光时,旗叶光系统Ⅱ的实际光合效率(ΦSPⅡ)、光化学淬灭系数(qP)、最大净光合速率(P_(max))及群体光合速率日均值均显著降低; PAR日均值≥64.53%自然光时小麦群体光合速率存在明显的补偿现象。综上,扁桃-冬小麦间作模式下,小麦光合能力及产量与遮阴程度密切相关,重度遮阴导致小麦单叶和群体光合能力及产量显著降低;轻度遮阴条件下,小麦旗叶光合能力无显著变化,群体光合速率存在明显的补偿现象,对产量无显著影响。     

基于地形校正的植被净初级生产力遥感模拟及分析

植被净初级生产力（NPP）模拟研究对碳平衡监测及深入理解碳循环具有重要意义。高空间分辨率、短重访周期的遥感数据和地形校正成为精准模拟山区植被NPP研究的必然选择。在利用DEM数据对太阳总辐射和气温进行地形校正的基础上,估算了研究区植被吸收光合有效辐射因子、温度胁迫因子、水分胁迫因子和典型植被类型的最大光能利用率,构建了改进的CASABTC估算模型,利用HJ-1CCD数据模拟了2009年大别山区植被的NPP,并探讨了其时空变化特征。结果表明：1）由该文模拟值与MOD17A3的精度验证结果分析,基于地形校正的CASABTC模型和HJ-1数据适合精确模拟山区植被的NPP;研究区NPP在冬季比在春、秋、夏季受地形起伏的影响大。2）该文模拟的年NPP平均值为413.7 g/(m2·a)比MOD17A3平均值偏小4.9%,在空间分布上前者更加详细,地表特征更明显。3）研究区2009年NPP模拟值范围为0～1143.6 g/(m2·a),研究区总面积66.1％的NPP值在200～600 g/(m2·a)之间;年总NPP为9.891×106t,约占全国年总NPP的3.2‰,整体上呈现高、低值区交错分布的不规则特点。4）月NPP值随季节而变化,所有植被类型的NPP季节变化曲线都呈典型的单峰分布,且不同植被类型NPP的季节变化幅度有差别。月NPP值的季节变化与气温、太阳总辐射及NDVI的季节变化基本吻合,而降水量年内分配不均与NPP无相关性特点。5）各植被类型的月NPP和总NPP随海拔高度上升而逐渐变大,对于后者当海拔高度上升至1100 m时达到最大值,继续上升,其保持在600 g/m2左右不变。该研究可为后续基于HJ-1数据的山区植被NPP模拟提供参考。     

草地净第一性生产力估算的研究进展

草地净第一性生产力(NPP)是全球变化与陆地生态系统研究的核心内容之一。草地NPP的模拟方法从站点实测法、统计模型发展到了机理性的过程模型,NPP的站点实测数据为统计模型和过程模型模拟结果提供参考。统计模型通过NPP和温度、降雨等气候因子或者直接与遥感获得的植被指数建立统计关系计算NPP;过程模型从机理上对植物的生物生理过程进行模拟并能够对NPP的影响因子进行分析,主要过程包括了光合作用、生长和维持呼吸、蒸散、氮吸收和释放、光合物质分配与分解,和季相变化等。遥感过程模型通过遥感手段获得地表覆盖状况、植被冠层结构变量值(如LAI)、地表反射率、地表辐射温度及土壤水分状况等作为重要参数应用到模型中,改善了模拟结果的时空精度,成为当前草地生产力模型的主要研究方向。最后对遥感监测草地NPP研究中存在的问题进行了分析并提出了展望。     

基于MODIS数据的陕西省植被净初级生产力与实际蒸散的变化关系分析

[目的]分析陕西省植被净初级生产力(NPP)及实际蒸散量(ET),为生态环境中碳循环、水循环特征提供理论支持。[方法]基于美国航天局(NASA)提供的净初级生产力产品(MOD17A3)及蒸散产品(MOD16)数据,利用GIS与数理统计等方法,对陕西省2000—2014年植被NPP与ET的时空分布特征及其关系进行分析。[结果]陕西省植被NPP与ET的分布特征均为南高北低;2000—2014年陕西省植被NPP在波动中呈现上升趋势,其中陕北地区增加最大,陕南地区增加最不显著;陕西省ET年际变化呈波动状态。植被NPP与ET空间相关性较显著,陕北地区相关系数极高,而陕南地区相关性并不显著。[结论]在较为干旱区域植被NPP与ET的关系更为密切。     

基于地形改进NPP指数的县域耕地产能测算

为了快速准确测算耕地产能,开展耕地质量和产能评价工作,落实"三位一体"的耕地占补政策,该研究尝试将耕地初级净生产力(NPP,Net Primary Productivity)运用于耕地产能测算。在具体提取NPP指数时,使用顾及地形要素对于太阳辐射影响改进的CASA模型,并在此基础上运用地理加权回归以及空间相关性的方法比较了NPP数据与耕地利用指数数据以验证NPP数据运用于耕地产能计算的可行性。研究结果表明:基于NPP获得的耕地产能数据总体呈现中部东南-西北轴线方向以及南部平原NPP指数较高东北、西南两侧较低的布局,而通过与耕地利用指数的地理加权回归发现两者有较强相关性。NPP指数可以直接用于耕地产能评价,能够提高工作效率和准确性。     

基于暗目标法和GF-1的农作物光合有效辐射反演

光合有效辐射是农田生产力和产量估算的依据,也是农作物参数遥感反演的主要研究内容。该文基于大气辐射传输模型,选择覆盖山东禹城市2014年4月－2014年12月共12景GF-1/WFV（wide field view,WFV）数据,结合浓密植被（暗目标）蓝光波段、红光波段之间反射率的线性关系,基于查找表（look-up table,LUT）技术反演了大气气溶胶光学厚度（aerosol optical depth,AOD）等大气参数,提出了基于蓝、绿、红3个离散波段反演光合有效辐射（photosynthetically available radiation,PAR）的算法。其中,浓密植被是根据WFV/NDVI（normal differential vegetation index）设置阈值的方式筛选的;红光波段与蓝光波段地表反射率的比例系数为1.7977,截距为0.0034,相关系数达0.9826,是根据美国地质调查局（U.S. Geological Survey,USGS）提供的典型植被波谱库数据理论计算获取;GF-1/WFV数据蓝、绿、红波段转换为400～700 nm谱段间光合有效辐射值之间的转换系数分别为0.09156、0.09951、0.1007。采用中国生态系统研究网络禹城实验站实测的 PAR 数据进行对比验证,光合有效辐射的总体精度达到了95.77%,误差绝对值平均为11.36 W/m2,平均误差小于5%,表明了该方法具有较高的精度。该方法不需要额外辅助数据,产品生产过程简单,是比较理想的GF-1/WFV数据光合有效辐射业务反演备选算法。     

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.     

Responses of native legume desert trees used for reforestation in the Sonoran Desert to plant growth-promoting microorganisms in screen house

Three slow-growing legume trees used for desert reforestation and urban gardening in the Sonoran Desert of Northwestern Mexico and the Southwestern USA were evaluated whether their growth can be promoted by inoculation with plant growth-promoting bacteria (Azospirillum brasilense and Bacillus pumilus), unidentified arbuscular mycorrhizal (AM) fungi (mainly Glomus sp.), and supplementation with common compost under regular screenhouse cultivation common to these trees in nurseries. Mesquite amargo (Prosopis articulata) and yellow palo verde (Parkinsonia microphylla) had different positive responses to several of the parameters tested while blue palo verde (Parkinsonia florida) did not respond. Survival of all tree species was over 80% and survival of mesquite was almost 100% after 10 months of cultivation. Inoculation with growth-promoting microorganisms induced significant effects on the leaf gas exchange of these trees, measured as transpiration and diffusive resistance, when these trees were cultivated without water restrictions.