水稻锰毒与铁素营养关系的研究

通过水培试验，研究了水稻锰毒与铁素营养关系，并探讨了过量锰对一些生理指标的影响。试验结果表明：地上部是生长介质中过量锰对水稻危害的主要部位；过量的锰增加铁在水稻根系的沉积，减少铁的吸收，改变体内铁的分布，降低铁的活性，诱发水稻缺铁胁迫；过量锰缺铁胁迫的水稻正常代谢受阻，叶片叶绿素、蛋白质含量减少，过氧化氢酶活性降低，而过氧化物酶活性增加     

热带优良牧草舍饲海南黄牛的适口性分析

以自由采食法舍饲海南黄牛,根据供试牛的采食速度和日采食量,比较营养生长期四种热带优良牧草品种的适口性大小。结果表明:热研4号王草的采食速度和日采食量远远大于其它三个牧草品种,适口性最好;热研2号柱花草和黑籽雀稗差异不显著,柱花草适口性略好于黑籽雀稗;热研8号坚尼草最低,与其它三个牧草品种差异极显著,适口性最差。个体牛对于四种牧草的采食速度和日采食量彼此之间差异不显著,对于四种牧草的喜食程度基本一致。建议舍饲时,以王草64%、柱花草16%、黑籽雀稗15%,坚尼草5%的食谱结构饲喂比较合理。     

水肥耦合对膜下滴灌甘蓝根系生长和土壤水氮分布的影响

水肥施用制度是影响水肥利用效率和作物产量的主要因素。该研究主要针对大棚种植甘蓝膜下滴灌下采用不同水肥施用制度时作物根系生长和土壤水氮分布开展试验观测分析,在已有研究推荐的氮肥用量范围中选取了3个氮肥用量(200、300和400 kg/hm2)与制定的灌水方案(上/下限:90%θf/75%θf、100%θf/85%θf和100%θf/75%θf,θf为田间持水率)建立了低水高肥、高水低肥和中水中肥3种水肥施用制度方案,在水利部节水灌溉示范基地大棚内开展了2季田间对比试验。试验结果表明:较高的灌水下限(85%θf)会增加甘蓝根系在0～20cm土层中的分配比例,较高的水肥用量能增加根系质量;处理2(高水低肥)的灌水施肥制度可使根系层土壤保持较高的含水率和较小的变异系数,且灌溉水向深层渗漏不明显,生育期内各处理土壤硝态氮和铵态氮的变化主要发生在0～40 cm土层,40 cm以下土层变化较小,而对于根系98%以上分布在40 cm以上土层的甘蓝来说,这有利于根系对N素的吸收利用,从而提高甘蓝对氮素的利用效率;施肥时灌水量较大会引起硝态氮和铵态氮向深层淋失的危险,且300和400kg/hm2的施氮量在作物收获后土壤表层硝态氮残留量较大。综合分析,该试验认为甘蓝适宜的施氮量200 kg/hm2,适宜的灌水下限85%θf、灌水上限100%θf,该结果可为设施膜下滴灌甘蓝水肥管理和减轻农业面源污染提供技术参考。     

甘肃省霜霉菌(Peronosporaceae)初步研究

本文汇录了作者收集的甘肃省22种霜霉菌。其中2个新种(已另文发表),即:寄生于藜科植物甜菜(Beta vulgaris L.)上的甜菜盘梗霜霉菌(Bremia betae Bai et Cheng sp.nov.)和寄生于唇形科植物薄荷(Mentha arvensis L.)上的薄荷霜霉菌(Peronospora menthae Cheng et Bai sp.nov.)。10个省内新记录种。对新种做了较详尽的形态描述,省内新记录种和省内已经报道过的种,仅分别将种名和寄主名列出。对近年来省内外其他学者报道的甘肃省霜霉菌新种共3种,我们还未采集到标本,也收录在文末附录内。至此,甘肃省共有霜霉菌25种。     

基于棉田原位高光谱数据的土壤pH值反演与制图研究

[目的] 研究快速、准确大面积监测农田土壤pH值,为大面积土壤改良和实现农田精细化管理提供科学支持。[方法] 以南疆阿拉尔市十二团棉田为研究区,采用网格采样法采集231个样点的原位高光谱数据,并同步采集其中116个样点的土壤样品;分析了原位高光谱反射率数据经不同预处理模式后的光谱数据与土壤pH值的相关性;采用偏最小二乘回归、支持向量机回归和随机森林3种建模方法分别建立了土壤pH值的高光谱反演模型,根据模型评价指标优选出最优模型对未采集土壤样点的pH值进行反演制图。[结果] 反射率经微分处理后可有效改善其与土壤pH值的相关性;反射率二阶微分的随机森林模型为所有模型中的最优模型,其验证集的R²为0.87,RMSE为0.04,RPD为2.53;最优模型反演的pH值数据插值所得数字图与实测pH值插值图的空间分布特征高度吻合,能客观反映土壤碱化的空间分布状况。[结论] 随机森林模型为原位反演南疆棉田土壤pH值的最优模型,克里金插值能够客观可视化表达研究区土壤pH值的分布状况。     

Effect of HCO $ _3^ - $ on rice growth and iron uptake under flood irrigation and drip irrigation with plastic film mulch

There has been a partial shift away from conventional flood irrigation (FI) practices for rice (Oryza stativa L.) production in water‐scarce northern China. Drip irrigation with plastic film mulch (DI‐PFM) can maintain high rice yields with significant water savings. However, rice seedlings often develop chlorosis when grown with DI‐PFM on calcareous soil. Bicarbonate is a concern with regard to chlorosis in calcareous soil. The objective of this simulation experiment was to determine the effect of irrigation method and irrigation water HCO $ _3^ - $ concentration on (1) soil pH and DTPA‐Fe concentration, (2) chlorophyll, total Fe, and active Fe concentrations of rice leaves, and (3) rice root and shoot biomass. The experiment consisted of four treatments: FI with water containing either 2 or 10 mM HCO $ _3^ - $ (referred to as FI‐2 and FI‐10, respectively) and DI‐PFM with water containing 2 or 10 mM HCO $ _3^ - $ (referred to as DI‐2 and DI‐10, respectively). The results show that the HCO $ _3^ - $ concentrations of the soil solution were greater under FI than under DI‐PFM, because more irrigation water was applied in the FI system. Soil pH increased as the HCO $ _3^ - $ concentration of the irrigation water increased. The increase in soil pH was greater in DI‐PFM than in FI. Soil DTPA‐Fe concentration, leaf SPAD values, leaf total Fe concentration, leaf active Fe concentration, shoot biomass, and root biomass decreased as the HCO $ _3^ - $ concentration of the irrigation water increased. The decreases were less under DI‐PFM than under FI. Overall, the results indicate that rice plants are more sensitive to the HCO $ _3^ - $ concentration of irrigation water under FI than under DI‐PFM.     

Optimum feeding rates in juvenile olive flounder,Paralichthys olivaceus,at the optimum rearing temperature

Two feeding trials were carried out to determine the optimum feeding rates in juvenile olive flounder, Paralichthys olivaceus, at the optimum rearing temperature. Fish averaging 5.0 ± 0.11 g (mean ± SD) in experiment 1 and 20.2 ± 0.54 g (mean ± SD) in experiment 2 were fed a commercial diet at the feeding rates of 0%, 3.0%, 4.0%, 4.25%, 4.5% and 4.75% body weight (BW) day^?1 and satiation (5.52% BW day^?1) in experiment 1 and 0%, 1.0%, 2.0%, 3.0% and 3.5% BW day^?1 and satiation (4.12% BW day^?1) in experiment 2 at 20 ± 1 °C. Both feeding trials lasted for 2 weeks. Results from experiment 1 indicated that weight gain (WG) and specific growth rate (SGR) of fish fed to satiation were significantly higher than those of fish fed at other feeding rates while feed efficiency (FE) and protein efficiency ratio (PER) of fish fed at 4.25% BW day^?1 were significantly higher than those of fish fed to satiation and fish fed at 3.0% BW day^?1 (P < 0.05). In experiment 2 WG, SGR and PER leveled out after the feeding rate of 3.5% BW day^?1 whereas FE reached a plateau at 3.0% BW day^?1. anova of FE indicated that the optimum feeding rates in 5.0 and 20 g juvenile olive flounder could be 4.25% and 3.0% BW day^?1, respectively. Broken line analysis of WG suggested the optimum feeding rates of 5.17% and 3.47% BW day^?1 in 5.0 and 20 g fish, respectively. Therefore, these results indicated that the optimum feeding rates could be >4.25 but <5.17% BW day^?1 for 5.0 g, and it could be >3.0 but <3.47% BW day^?1 for 20 g size of juvenile olive flounder at the optimum rearing temperature.     

羽扇豆炭疽病病原鉴定及室内药剂筛选

通过组织分离法对长春市百花园种植的羽扇豆(Lupinus micranthus)炭疽病病样进行分离和鉴定,同时进行了对20种药剂的敏感性试验.结果 表明:通过对病原菌形态特征的观察和多区段DNA序列分析,确定该病害由Colletotrichum lupini引起.病原菌生物学特性研究结果表明,病原菌菌丝生长和产孢的最适温度为25℃,光照下有利于菌丝生长和产孢,最适pH=7～8.病原菌在PDA培养基上菌丝生长和产孢最佳;在以蛋白胨为氮源、葡萄糖为碳源的培养基上菌丝生长最快,以硝酸钾为氮源、山梨醇为碳源的培养基上产孢最好;菌丝致死温度为51℃,孢子致死温度为52℃.采用生长速率法和孢子萌发法测定了病原菌对20种杀菌剂的敏感性,该病原菌菌丝和孢子均对质量分数60％唑醚代森联、250 g·L-1吡唑醚菌酯的敏感性较高,EC50＜1 mg·L-1.     

玉米秸秆在等离子体加热流化床上的快速热解液化研究

为了进一步研究生物质热解液化技术,寻找较为理想的生物油产率所对应的试验条件,设计制作了以等离子体为主热源的流化床热解液化装置,反应器的内径为52 mm,高1150 mm。以玉米秸秆粉为原料在不同温度、不同喂料速率下进行一系列的热解液化试验。试验结果表明：喂料速率在0.6～0.7 kg/h时,生物油产率较高;反应温度升高,生物油产率增高,但是当反应温度超过750 K时,产率反而随温度的上升而下降。使用色质联用仪(GC-MS)对生物油进行了成分分析,4种试验条件下制取生物油的主要成分均为乙酸、羟基丙酮、水、乙醛、呋喃等,试验条件不同各主要成分的相对含量有所不同。高含水量和含氧量降低了生物油的热值和稳定性,容易发生聚合反应,必须经过改性后才能应用。所采用的试验装置及试验方法亦可用于以其它原料获取生物油的研究。     

2,3-环氧蒎烷无溶剂重排合成龙脑烯醛

以2,3-环氧蒎烷为原料,在无溶剂的条件下以ZnCl2为催化剂进行重排合成龙脑烯醛.研究结果表明,ZnCl2用量为环氧蒎烷的4％,在80℃下反应1h时,2,3-环氧蒎烷的转化率达99.19％,龙脑烯醛的选择性达到74.33％;以MCM-41、自制SO4-ZrO2-MCM-41为催化剂进行无溶剂重排,2,3-环氧蒎烷的转...