Effect of nitrogen form and application method on incidence and severity ofPhytophthora crown and root rot of apple trees

The effect of ammonium nitrate broadcast as a soil or through irrigation, urea applied as a foliar spray, and monoammonium phosphate applied as a planting hole treatment on the incidence ofPhytophthora crown and root rot of apple trees was determined under orchard conditions in the Okanagan Valley of British Columbia, Canada. Results from the eight year study showed that ammonium nitrate applied as a single dose in spring at 240 g tree^–1 year^–1, as a split dose at 120 g tree^–1 each in spring and early autumn, and in irrigation water (fertigation) at 7.5 g tree^–1 wk^–1 for 10 wk year^–1 significantly increasedPhytophthora crown and root rot of Macspur on MM106 rootstock. There was no significant difference inP. cactorum infection between the unfertilized control and treatments with urea applied as a foliar spray at 1.0 kg 100 l^–1 of water in spring and early autumn, and monoammonium phosphate applied as a planting hole treatment at 1 g l^–1 of soil at planting time.     

磷酸脒基脲与聚磷酸铵协同阻燃的木粉/HDPE复合材料

采用锥形量热仪(CONE)、极限氧指数(LOI)、热重分析(TGA)和力学试验等研究手段,分析聚磷酸铵(APP)、磷酸脒基脲(GUP)及二者复配(GUP/APP)对木粉/高密度聚乙烯(WF/HDPE)复合材料燃烧性能、热降解行为以及力学性能的影响.CONE研究结果表明:APP可显著降低WF/HDPE复合材料的热释放,但同时也使得复合材料的烟释放增加;将GUP与APP按适当比例复配不仅可以有效抑制复合材料的热释放,而且可以降低烟释放速率,表现出较好的协同阻燃和抑烟作用.TGA结果表明:GUP与APP复配使得WF/HDPE复合材料的初始热分解温度降低,残炭产率提高.此外,GUP和APP复配阻燃WF/HDPE复合材料具有较高的氧指数和较小的力学性能损失.     

缺磷条件下蔗糖对水稻磷素吸收利用起重要作用

 研究了水稻缺磷条件下蔗糖对其生长、磷素吸收利用的影响。结果表明,外加蔗糖可以提高水稻缺磷条件下的生物量,可以促进水稻缺磷条件下的磷素吸收;利用磷转运蛋白基因OsPT2启动子+ GUS报告基因转基因水稻材料,进一步探讨了蔗糖在水稻缺磷条件下促进磷素吸收利用的分子机理。结果表明,水稻磷转运蛋白OsPT2参与了蔗糖促进缺磷水稻的磷素吸收与转运。     

纳米磷酸三钙/明胶/鹿茸多肽复合材料的制备及对人成骨细胞增殖、分化及矿化的影响

探讨反相微乳液法制备的β-纳米磷酸三钙/明胶/鹿茸多肽复合材料(简称纳米复合材料)对人成骨细胞功能的影响.利用反相微乳液法制备纳米复合材料,扫描电镜观察其形态,EDX与SELDI-TOF-MS分析对复合材料进行表征.采用MTT比色法、茜素红染色法检测纳米复合材料对体外培养的人成骨细胞hFOB1.19的增殖、矿化结节形成的影响;采用全自动生化分析仪检测hFOB细胞碱性磷酸酶活性(ALP).结果表明该纳米复合材料可促进人成骨细胞增殖,提高ALP活性并增加矿化结节形成的数量,可促进人成骨细胞的增殖、分化成熟及矿化.     

柠檬酸对温室土壤磷有效性的影响

温室菜地土壤面临磷肥大量投入, 磷肥有效性低下等问题, 为提高土壤中磷素的有效性, 减少磷肥施用, 亟待开展相关研究。以番茄为供试对象, 研究温室番茄地施用柠檬酸对土壤有效磷时空变化及番茄产量的影响, 试验设置磷肥和柠檬酸2个因素4个水平, 采用完全随机设计, 分别为:0(CA0)、0.42(CA1)、0.84(CA2)、1.26(CA3)kg·hm^-2和0(P0)、96(P1)、168(P2)、240(P3)kg·hm^-2.结果表明:与对照相比, 施加柠檬酸后土壤pH极显着降低(P<0.01),CA3P0处理使土壤pH降低了0.62;不施加磷肥时, 柠檬酸促进土壤磷素的释放, 提高了土壤有效磷的含量;施加磷肥后, 柠檬酸和磷肥交互作用可以显着提高表层0~20 cm土壤有效磷含量, 但是过多施用柠檬酸和磷肥CA3P3处理使表层0~20 cm土壤有效磷含量降低, 使20~40 cm土壤有效磷含量增加, 并提高有效磷向下运移的可能性。合适的柠檬酸和磷肥配比CA2P2既可以获得较高番茄产量6.02 t·hm^-2,又可以减少30%的磷肥施用量, 同时降低磷素向深层运移的风险。     

不同种源枫香磷响应指标的主成分分析

采用裂区砂培试验,研究枫香对 P 水平响应性状的相关性,进行了主成分分析,旨在找出影响其生物量的主导因子、不同种源的最适生长 P 浓度及优良耐 P 胁迫种源.相关分析表明,除 P 利用率具有一定的稳定性外,生物量与其他响应性状相关性显著;低 P 胁迫造成的 N 吸收利用的变化对枫香影响更大.主成分分析表明,枫香生物量差异的主导因子是 N、P 吸收性状,其次是 P 利用性状.标准化主成分得分排序认为南昌种源具有较好的 N、P 吸收利用机制;南丹种源具有较好的种源特性,P 利用率较稳定.根据我国土壤有效 P 含量多样性的现状筛选出具有广适性特点的南昌种源和具有较好耐低 P 胁迫特性的南丹种源.     

贵州磷肥施用对耕地土壤重金属铅的影响

伴随工业发展和环境污染加剧,铅污染也越来越受关注。铅污染的土壤会直接影响农作物的产量和质量,而且可以通过食物链进入人体危害人类健康。文章较为全面的总结了贵州土壤重金属铅的研究现状,分析了贵州省近十年来磷肥施用及其对耕地土壤重金属铅的影响。结果表明:全省磷肥施用量整体呈上升趋势,耕地土壤铅属于清洁状态,但是局部的污染是存在的;磷肥的施用会增加耕地土壤铅含量,但是低贡献率不会使耕地土壤重金属铅短期内达到污染水平;磷肥的施用改变耕地土壤pH值,进而影响耕地土壤铅的生物有效性,pH值升高,铅的生物有效性降低;磷肥的施用还会降低非残渣态铅含量。研究可为深入探讨磷肥施用对耕地土壤重金属铅的影响和污染防治提供依据。     

日粮钙磷比例对肉用仔鸡体钙和体磷比影响的研究

实验选用一日龄AA肉用仔鸡270只,从16日龄起,分成5个处理,研究了日粮—血液—骨骼三者间钙磷比值的相关性。结果表明:日粮钙和有效磷(AP)比值与血清离子钙和无机磷的比值呈显著正相关(P<0.01),血清离子钙和无机磷的比值与胫骨钙和磷比值呈显著正相关(P<0.01)。     

脱落酸与赤霉素对瓜尔豆蔗糖代谢酶类的影响

研究了脱落酸与赤霉素对瓜尔豆叶片和种子发育过程中糖代谢相关酶活性的影响。结果表明,脱落酸与赤霉素处理均能降低酸性转化酶活性,赤霉素(500mg/L)对中性转化酶与酸性转化酶活性降低程度最大。赤霉素(500mg/L及750mg/L)在整个生育期增加叶片蔗糖合成酶与蔗糖磷酸合成酶活性,脱落酸(2.64mg/L,1.32mg/L及3.96mg/L)及赤霉素(250mg/L)均不同程度地降低蔗糖合成酶与蔗糖磷酸合成酶活性。各处理间差异达到显著水平。低浓度的脱落酸(1.32mg/L)降低种子中性转化酶和蔗糖磷酸合成酶活性;高浓度的脱落酸(2.64mg/L及3.96mg/L)能提高种子的中性转化酶、酸性转化酶、蔗糖合成酶与蔗糖磷酸合成酶活性。低浓度的赤霉素(250mg/L)能相对降低瓜尔豆种子内的中性转化酶、酸性转化酶、蔗糖合成酶与蔗糖磷酸合成酶活性,而高浓度的赤霉素(500mg/L及750mg/L)则明显地升高中性转化酶、酸性转化酶、蔗糖合成酶与蔗糖磷酸合成酶活性,表现出较强的蔗糖合成与分解能力。 ;     

Study on Adsorption of Suspended Sediments to Phosphate in the Three Gorges Reservoir Area

Suspended sediments play an important role in the transformation process of pollutants in rivers.The adsorption characteristic of suspended sediments in Three Gorges Reservoir Area to phosphate was studied in this paper.Based on the indoor adsorption balancing experiment and kinetic modeling experiment,the main factors for adsorption process of sediments(particle size of sediment,initial concentration etc.) were discussed.The major results of the experiment were as follows:(1) Three kinds of suspended sediments with different particle sizes were used for the study of adsorption characteristic with different sediment concentration.The amount of phosphate adsorption increased with the increase of the sediment concentration and sediment particle size.(2) With the help of Langmuir isotherm theory,the related parameters in kinetic model were estimated,the experiment results indicated that the adsorption isotherm of phosphate in Three Gorges Reservoir Area fitted with the fifth type of Langmuir adsorption isotherm,the maximum amount of phosphate adsorption would emerge when the phosphate concentration was relatively high,but it would move down when the phosphate concentration increased afterwards.(3) Phosphate adsorption increased with the increase of initial phosphate concentration,the average time for adsorption balance was 2-4 hours.