不同耐旱性玉米初生根和次生根中铁、锰、铜、锌、钠含量分析

以生长于田间的玉米掖单13(耐旱性玉米)和丹玉13(不耐旱性玉米)为试验材料,应用ICP对供试玉米的初生根和第一、二、三、四、五、六、七、八和第九层次生根的铁、锰、铜、锌和钠元素含量等项指标进行了测定和比较分析。结果表明:除个别根外,耐旱性玉米不同类型根中的铜含量极显著高于不耐旱性玉米根系(P0.01);根中的锰元素含量和锌元素含量极显著高于不耐旱性玉米根系(P0.05);根系中铁元素含量和根系中的钠元素含量在两品种玉米根系之间差异未达显著水平(P0.05)。     

不同磷水平玉米自交系根系形态及吸收氮、钾差异研究

通过盆栽试验研究4个自交系玉米在低磷和正常供磷两个磷水平下的磷效率差异、根系形态与磷效率的相关性及吸收氮、钾营养的差异。结果表明:在土培条件下,玉米的磷效率与吸磷量存在极显著正相关关系,根体积、根半径与磷效率的相关性均呈显著正相关,说明在缺磷条件下吸收效率高的基因型磷效率较高,且有较大根体积和根半径。同时,缺磷也导致玉米对氮、钾吸收的降低。     

水、氮调控对夏玉米根系特性的影响

采用土柱模拟试验研究了水、氮调控措施对夏玉米根系生长状况及其与籽粒产量之间的关系.结果表明:水分对根系干重、根系活力、根系表面积的影响较氮肥大;根系干重随土层深度增加而减小,0～ 10 cm土层尤为明显;0～20 cm根系密度较高,根系密度随土层深度增加先减小后上升;根干重和根系密度随施氮量增加而降低,根冠比基本呈减小趋势;氮肥能提高玉米根系活力.根干重、根系密度、根表面积和根系活力与籽粒产量和玉米地上部分干物质量均呈极显著相关关系;根冠比只与地上部分相关;根表面积和根系活力之间呈极显著相关关系;根系活力和根系吸氮能力对玉米生长和籽粒的形成有很重要的作用,存在显著正相关性.     

玉米线辣椒套作对线辣椒根际、非根际土壤微生物、酶活性和土壤养分的影响

实验旨在研究不同种植模式、作物种间不同的根部隔离处理对线辣椒根际与非根际土壤微生物数量、土壤酶活性及土壤养分有效含量的影响.结果表明:套作栽培的线辣椒根际、非根际土壤微生物数量、酶活性均高于单作栽培.与膜隔处理相比,网隔与无隔处理的根际、非根际土壤微生物数量及酶活性均有提高,其中以网隔处理最高.各处理根际土壤有机质、有效磷、有效钾含量均低于非根际土壤,但碱解氮含量表现为根际土壤高于非根际土壤.网隔处理中尼龙网减缓了玉米根系对线辣椒根系营养的直接竞争,同时玉米根系根际效应使其根际、非根际土壤养分含量在所有处理中最高.土壤微生物主要类群数量是影响土壤酶活性主要因子,与土壤酶活性显著相关.有机质、碱解氮含量与土壤酶活性、微生物数量呈极显著相关,有效磷含量与土壤酶活性、微生物数量呈正相关.土壤真菌数量、脲酶活性与有效钾含量呈负相关.     

玉米线辣椒套作对线辣椒根际、非根际土壤微生物、酶活性和土壤养分的影响

实验旨在研究不同种植模式、作物种间不同的根部隔离处理对线辣椒根际与非根际土壤微生物数量、土壤酶活性及土壤养分有效含量的影响。结果表明：套作栽培的线辣椒根际、非根际土壤微生物数量、酶活性均高于单作栽培。与膜隔处理相比,网隔与无隔处理的根际、非根际土壤微生物数量及酶活性均有提高,其中以网隔处理最高。各处理根际土壤有机质、有效磷、有效钾含量均低于非根际土壤,但碱解氮含量表现为根际土壤高于非根际土壤。网隔处理中尼龙网减缓了玉米根系对线辣椒根系营养的直接竞争,同时玉米根系根际效应使其根际、非根际土壤养分含量在所有处理中最高。土壤微生物主要类群数量是影响土壤酶活性主要因子,与土壤酶活性显著相关。有机质、碱解氮含量与土壤酶活性、微生物数量呈极显著相关,有效磷含量与土壤酶活性、微生物数量呈正相关。土壤真菌数量、脲酶活性与有效钾含量呈负相关。     

外源亚精胺对干旱胁迫下玉米幼苗叶片生理及根系特征参数的影响

采用营养液水培法,以两种不同耐旱类型玉米品种先玉335(抗旱性强)和丰禾1号(抗旱性弱)为试验材料,研究了利用20%聚乙二醇(PEG-6000)模拟的干旱胁迫下根施外源亚精胺(Spd,0.1 mmol/L)对玉米幼苗干(鲜)重、根系特征(根长、根表面积、根体积)、叶片相对含水量、叶绿素含量及细胞膜透性的影响。结果表明:正常条件下,外源Spd处理可显著提高两个玉米品种的干(鲜)重、株高、根长及根表面积,但对根体积、根平均直径、叶片相对含水量、叶绿素含量及细胞膜透性的影响较小。干旱胁迫下,外源Spd处理可显著提高玉米幼苗干(鲜)重、叶片相对含水量和叶绿素含量;增加根系数量,且随0~1.0 mm径级比例根系数量的增加,其根系长度增加幅度相应加大,随0.5~1.5 mm径级比例根系数量的增加,其根系表面积增加幅度相应加大;使玉米幼苗叶片细胞膜透性显著降低;对抗旱性弱的丰禾1号影响更为明显。因此,适宜浓度的外源Spd可以减轻干旱胁迫对玉米幼苗的伤害,并能更好地缓解干旱胁迫对抗旱性弱的玉米品种生长的抑制作用。     

小麦／玉米间作优势及地上部与地下部因素的相对贡献研究

采用田间微区试验以及地下部种间根系分隔技术研究了玉米覆膜与不覆膜两种情况下小麦/玉米间作优势及地上部因素和地下部因素对间作优势的相对贡献。结果表明,玉米不覆膜时小麦/玉米间作籽粒产量和生物产量土地当量比分别为1.30、1.29,具有明显的产量间作优势,玉米覆膜时小麦/玉米间作籽粒产量和生物产量土地当量比分别为1.41、1.40,具有极显著的产量间作优势;玉米不覆膜时小麦/玉米间作氮、磷、钾养分吸收优势明显,玉米覆膜时小麦/玉米间作具有极显著的氮、磷、钾养分吸收优势。地上部因素和地下部因素对小麦/玉米间作中籽粒产量和生物产量间作优势的相对贡献,当玉米不覆膜时分别为75%、25%,当玉米覆膜时均为地上部占67%、地下部占33%。当玉米不覆膜时,地上部和地下部因素对小麦/玉米间作氮、磷养分吸收优势的相对贡献均分别为67%与33%,钾则地上部与地下部贡献相等(各占50%);当玉米覆膜时,地上部和地下部因素对小麦/玉米间作氮、钾养分吸收优势的相对贡献均具有同等重要性(各占50%),对磷吸收的贡献分别占55%与45%。     

施氮量对滴灌超高产春玉米根系时空分布及产量的影响

为探究不同施氮量对北疆滴灌超高产春玉米根系生长时空分布特征的影响,采用土壤剖面取样法大田研究了0、150、300、375和450 kg·hm~(-2)5个施氮水平对春玉米0~60 cm土层根系生长及产量的影响。结果表明,滴灌超高产春玉米根干重和根长度主要集中在0~20 cm土层,且生育期内表现为先升高而后降低变化,吐丝期达到峰值。增加施氮量显著提高各土层根干重密度和根长密度。大喇叭口期配合吐丝期施氮可明显延缓春玉米各土层根系衰老,特别是显著提高灌浆期20~60 cm土层根系活力。当施氮量在300 kg·hm~(-2)左右时,春玉米根系长势相对较好,此时农学利用率为13.8 kg·kg-1,籽粒产量为17 117 kg·hm~(-2),较缺氮处理增产32.10%。若继续增加施氮量,各土层根系参数表现为降低变化趋势,且增产不显著,农学效率明显降低。综合考虑,该地区春玉米获取超高产的适宜施氮量可确定为拔节期结合大喇叭口期配合吐丝期施氮300 kg·hm~(-2)。     

多年生香豌豆扦插试验研究初报

本试验对优良牧草多年生香豌豆茎段不同部位和不同扦插基质的生根能力分别进行了观测分析。结果表明:多年生香豌豆梢部茎段扦插生根能力最强,其生根率达到66.67%,根长、根表面积和根体积极显著(P0.01)高于其它茎段。地上部分生长状况为新叶数之间差异不显著而新梢高之间显著(P0.05);混合基质扦插的生根能力最强,其生根率达到65.3%,且根表面积和根体积极显著(P0.01)高于其它基质。地上部分的生长状况为新叶数之间差异显著(P0.05)而新梢高之间不显著。     

玉米植株叶片和根系的抗旱性差异分析

为了研究玉米(Zea mays L.)的叶片和根系抗旱性差异,以田间种植的玉米品种‘掖单13’和‘丹玉13’为材料,在拔节期取样,分别对玉米的叶片、叶鞘及初生根、第1层至第5层次生根的基部、中部和根尖的保水能力进行了研究。结果显示,拔节期玉米不同器官保水能力不同,叶鞘的保水能力最强,其次是根系,叶片的保水能力最弱。初生根和各层次生根不同部位相比较,根基部保水能力最强,其次是根中部,根尖的保水能力最弱;不同类型根保水能力相比较,初生根基部、中部和根尖部分的保水能力均最弱;第1层至第5层次生根基部的保水能力是根系发生时间越晚,其保水能力越强;根中部和根尖的保水能力在第1层至第5层次生根中有不同表现。     

MAP法处理农药行业氨氮废水的研究

向氨氮废水中投加磷源和镁源可以形成磷酸铵镁（MAP）沉淀。本试验采用轻烧镁粉作为MAP法的镁源。试验对配比、pH、反应时间对氨氮去除率的影响进行了研究。确定了最佳反应条件。实验结果表明：当摩尔比N：Mg：P=1：8：1（将轻烧镁粉看作纯氧化镁计算）、pH=7、反应时间为50min时,氨氮去除率达到92%,剩余磷含量为2mg/L。     

叶面喷施镁肥对缺镁番茄养分吸收和分配的影响

针对近年来北方日光温室中栽培番茄缺镁普遍发生和日益严重的问题,研究了叶面喷施MgSO_4、Mg(NO3)2及不同施用量对秋冬茬缺镁番茄K、Ca、Mg吸收和分配的影响,以期为番茄缺镁的矫正提供科学依据。结果表明:(1)随番茄生育进程各处理番茄叶片Mg和K含量呈下降趋势,Ca含量先下降后基本稳定,其中,Mg和Ca以第1穗果膨大期到第2穗果膨大期下降幅度最大,降幅分别为17.8%和39.1%。(2)喷施Mg肥显著提高叶片中Mg的浓度及携出量,喷施含镁0.4%的MgSO_4·7H_2O溶液叶片镁含量及携出量较对照分别提高了1.55和1.78倍,而对根、茎和果实中Mg的浓度及携出量无明显影响;从产量上看,喷施含镁0.2%和0.4%MgSO_4·7H_2O及0.2%Mg(NO3)2·6H_2O溶液与不喷施相比产量分别提高了8.0%、8.9%和5.3%,但差异不显著。(3)土壤交换性K/Mg均大于适宜值,K、Mg养分比例严重失调,而石灰性土壤养分失调后叶面补施Mg肥,Mg从叶片向其他部位的转运有限,必须降低钾肥施用量,使养分平衡供应。     

重庆市不同类型植烟土壤肥力状况研究

对重庆市不同类型植烟土壤取样217个（石灰岩土土样20个,黄壤土样133个,黄棕壤土样34个,紫色土土样18个,黑色石灰土土样12个）,研究不同类型植烟土壤肥力状况。经测定分析得出：重庆烟区土壤大多呈酸性,有机质含量较高,与农户施用有机肥有关。大量元素中全氮含量较高,速效氮含量适中;钙、镁、硫等中量元素和铁、锰、铜、钼、锌等微量元素含量丰富,较适合烤烟生长。根据分析结果提出了控氮,适当补磷和硼,增钾,普遍增氯禁硫的原则以改良土壤质量。     

The influence of some growth retardants on the growth and mineral composition of plants

The influence of the growth retardants 3-chlorobenzyl-tri-n-butylammonium bromide (B₃), 4-chlorobenzyl-tri-n-butylammonium bromide (B₄), α-naphthylmethyl-tri-n-butylammonium bromide (α-NMB) and the commercial products 2-chloroethyltrimethylammonium chloride (chlormequat chloride) and N-dimethylaminosuccinamic acid (aminozide) on the growth characteristics and chemical composition of plants growing in soil under glasshouse conditions has been studied. The height, fresh and dry weights and content of nitrogen, phosphorus, potassium, calcium, magnesium, iron and manganese of treated plants were compared with those of control plants. The chlorophyll content of certain leaves was also estimated. The retardants markedly altered the growth habit of plants and usually led to a decrease in fresh and dry weights. The percentage of plant nutrient elements in the dry matter was increased by treatment.     

Effects of nitrogen, phosphorus, potassium and calcium nutrition on strawberry anthracnose

The effects of a range of concentrations of four nutrients – nitrogen, phosphorus, potassium and calcium – in fertilizer solutions on the severity of anthracnose on strawberry cv. Nyoho cultivated under a noncirculation hydroponics system were determined after inoculation with Colletotrichum gloeosporioides . Crop growth and tissue nitrogen, phosphorus, potassium and calcium contents of the entire above-ground parts of the plant were also investigated. Elevated nitrogen and potassium concentrations in the fertilizer solution increased disease severity in contrast to phosphorus and calcium. Treatment with either NH₄ or NO₃ nitrogen was not significantly different. The dry weight of the strawberry plants increased significantly with elevated concentrations of nitrogen ( R ² = 0·9078) and phosphorus ( R ² = 0·8842), but was not influenced by the elevated amounts of potassium ( R ² = 0·8587) and calcium ( R ² = 0·6526) concentrations.     

Influence of Ring Nematode Infestation and Calcium, Nitrogen, and Indoleacetic Acid Applications on Peach Susceptibility to Pseudomonas syringae pv. syringae

ABSTRACT Two field experiments were conducted to study the effects of added nitrogen, calcium, and indoleacetic acid, in the presence or absence of ring nematodes (Mesocriconema xenoplax), on susceptibility of peach to bacterial canker. When noninfested soil was inoculated with ring nematodes, peach tree susceptibility to bacterial canker infection caused by Pseudomonas syringae pv. syringae was dramatically increased after a period of 2 years. However, no evidence was found that ring nematode infestation increased tree water stress or, in turn, altered plant calcium uptake. Soil fumigation with methyl bromide prior to planting in a commercial orchard significantly reduced both nematode populations and peach tree susceptibility to bacterial canker infection when compared with nonfumigated treatments. In both experiments, tree susceptibility, as measured by canker length following inoculation of stems with P. syringae pv. syringae, was negatively correlated with plant tissue nitrogen content and positively correlated with tissue calcium content. A principal components analysis showed that tissue nitrogen and calcium levels were negatively correlated, and that high-nitrogen, low-calcium tissues were less susceptible to bacterial canker than low-nitrogen, high-calcium tissues. These results indicate that the increased susceptibility of peach to P. syringae pv. syringae under nematode infestation conditions is mediated by both nutritional effects (primarily nitrogen) and nutritional-independent effects, but do not support previous reports of beneficial effects of calcium for reducing bacterial canker.     

Population dynamics of citrus leaf miner on different varieties of citrus in correlation with abiotic environmental factors in Sargodha District,Punjab, Pakistan

From January 2010 to December 2011, samples of leaves from citrus varieties Kinnow, Musambi and Feutral were taken from the five tehsils (administrative subdivisions) of Sargodha District in Pakistan including Sargodha, Bahalwal, Silanwalli, Sahiwal and Kotmomin, to study the population trends in citrus leaf miner (CLM), Phyllocnistis citrella (Stainton) (Lepidoptera: Gracillariidae), and its correlation with various environmental factors: (temperature, humidity and rainfall); plant morphological factors: moisture contents of leaves, leaf thickness, surface area (cm ² ), and biochemical percentage of calcium, potassium and magnesium in leaves. The maximum population of CLM was observed on Kinnow and Feutral, followed by Musambi. The effect of these factors on the larval population was 8.39- 2.30(Mg)+2.73(K)-0.398(Ca)-0.100(Temp)0.038(Humidity)+0.567(Rain)+0.07(Moist) 1.01 (Thickness)-0.022(Surface area). This equation revealed that magnesium, calcium, temperature, humidity, leaf thickness and leaf surface area are negatively correlated with larvae population, whereas potassium, rainfall and moisture are positively correlated with larvae population.     

紫杉木霉突变株UL60-11产木霉菌素的发酵条件优化

为了提高紫杉木霉Trichoderma taxi ZJUF0986突变株UL60-11木霉菌素的产量,采用单因素试验筛选出菌株UL60-11生长及产素的最佳碳氮源为葡萄糖、淀粉、蛋白胨、酵母粉、酒石酸铵;通过均匀设计与正交试验相结合优化出最佳培养基配方：葡萄糖23g、淀粉15g、蛋白胨5g、酵母粉3g、酒石酸铵2g、硫酸镁0.25g、磷酸二氢钾1.0g、氯化钠0.2g、硝酸钙0.4g。在最适工艺条件：初始pH4.0、温度25℃、种龄48h、10%接种量1、00ml/500ml的装液量和150r/min下摇瓶发酵试验,木霉菌素产量达到632.16μg/ml,比优化前提高32%。     

Growth, development and nutrient accumulation in Senecio vulgaris L. and Chenopodium album L.

Growth, development and nutrient accumula tion in Chenopodium album and Senecio vulgaris grown in pure and mixed stands were investi gated through several experiments conducted under glasshouse conditions. Results showed that the two weeds were different in their growth, development and tissue concentration and accu mulation of mineral elements. The mean concen trations of nitrogen, phosphorus, potassium, calcium and magnesium in shoots of C. album were higher than those of S. vulgaris, while root concentrations of nitrogen, potassium and mag nesium were lower for C. album. Marked dif ferences between the two weed species in their responses to different potassium levels were found. C. album had a high specific requirement for potassium while the reverse was true for S. vulgaris. The competitive ability and accumula tion of nutrients by C. album appeared to be greatly dependent on the availability of high potassium levels in the media.