纳米氧化铁对花生生长发育及养分吸收影响的研究

.通过温室砂培试验研究了纳米氧化铁与有机肥、腐殖酸配合施用对花生生长发育和吸收铁肥的影响。结果表明,纳米氧化铁能够显著地促进花生的生长发育和光合作用。有机肥和纳米氧化铁配施(OM-Fe)处理,花生叶片叶绿素含量最高,为2.89mg/g,显著高于柠檬酸铁处理(CT-Fe);纳米氧化铁和有机肥、腐殖酸配施可增强铁在植株体内的移动性,使铁向叶部转移,叶部的含铁量明显增加。纳米氧化铁与有机肥配施(OM-Fe)、纳米氧化铁(Nano-Fe)、纳米氧化铁与腐殖酸配施(HAs-Fe)处理,其植株叶部含铁量分别为218.95mg/kg、207.48mg/kg、206.64mg/kg,均大于柠檬酸铁处理(187.00mg/kg),提高了铁的利用率。此外,纳米Fe2O3还有利于促进花生对氮、磷、钾养分的吸收和利用。     

水利“948”水保生态项目综述

水土保持生态建设需要科技支撑,科学技术应当走向生态建设的主战场。抓住国家实施“948”项目的契机,积极引进国外技术提升水保生态建设。黄河上中游管理局和长江委应用“3S”技术,为创新水保科技做出了贡献。水利部沙棘开发管理中心提炼沙棘黄酮,与有关各省优化沙棘良种,建设繁育基地,促进了沙棘产业发展。水利部科技推广中心、中国水科院、南京水科院、水土保持研究所和各省、市、县有关单位,因地制宜创新水土流失综合防治技术,拓展了服务领域,改善了生态环境。引进的各个项目效益突出,工作中的经验和做法可供借鉴,其启示和影响是深远的。     

冬小麦—夏玉米轮作周期内碱解氮、硝态氮时空变化及施氮安全值的研究

利用 3年 6季氮肥试验研究了冬小麦—夏玉米轮作制度下 ,冀东褐土剖面碱解氮、NO-3 -N含量时空迁移变化和土壤氮素安全值指标。结果表明 ,土壤碱解氮自上而下依次递减 ,NO-3 -N呈“V”字型变化 ,二者均与施肥水平及植株生长状况密切相关 ,在 2 0～ 40cm区域出现碱解氮亏缺区 ,N2处理较为明显。N2处理的地下水NO-3 -N含量已超标 ,建议高产条件下土壤环境投氮安全值为 42 0～ 450kghm- 2 较为适宜     

辽宁省小流域管理信息系统的建立

以小流域为单元进行水土流失综合治理,是具有中国特色的水土保持治理技术。利用3S技术建立小流域管理数字化信息系统,是以遥感影像为背景,确定集水区域,以山脊为界,面积控制在10～20km~2,同时考虑行政边界,在计算机上,以地理信息软件为技术平台,绘制小流域边界,并输入18位小流域编码。根据管理需要,按市、县、乡、按流域、按水库上游等各种管理方式绘制成若干种小流域图,为各级水土保持管理部门提供服务,提高水保工作的管理水平,为领导决策提供重要的依据。     

DNA甲基化与细胞分化

DNA甲基化与DNA遗传信息的传递及组织特异性基因的正确表达存在着十分密切的关系。DNA甲基化受组蛋白H 3和DNA甲基化转移酶的调控;甲基化的DNA与许多的蛋白质共同相互作用,调控基因转录,从而导致基因印迹和基因沉默,使细胞向特定方向分化。本文重点综述了DNA甲基化位点、甲基化转移酶及DNA甲基化相关的蛋白质;DNA甲基化与基因印记、基因沉默的关系及其对细胞分化的影响。     

Increased degradation of phenanthrene in soil by Pseudomonas sp. GF3 in the presence of wheat

A phenanthrene-degrading bacterial strain Pseudomonas sp. GF3 was examined for plant-growth promoting effects and phenanthrene removal in soil artificially contaminated with low and high levels of phenanthrene (0, 100 and 200 mg kg⁻¹) in pot experiments. Low and high phenanthrene treatments significantly decreased the growth of wheat. Inoculation with bacterial strain Pseudomonas sp. GF3 was found to increase root and shoot growth of wheat. Strain GF3 was able to degrade phenanthrene effectively in the unplanted and planted soils. Over a period of 80 days the concentration of phenanthrene in soil in which wheat was grown was significantly lower than in unplanted soil (p<0.05). At the end of the 80-d experiments, 62.2% and 42.3% of phenanthrene had disappeared from planted soils without Pseudomonas sp. GF3 when the phenanthrene was added at 100 and 200 mg kg⁻¹ soil, respectively, but 84.8% and 70.2% of phenanthrene had disappeared from planted soils with the bacterial inoculation. The presence of vegetation significantly enhances the dissipation of phenanthrene in the soil. There was no significant difference in soil polyphenol oxidase activities among the applications of 0, 100 and 200 mg kg⁻¹ of phenanthrene. However, the enzyme activities in planted and unplanted soils inoculated with the strain Pseudomonas sp. GF3 were significantly higher than those of non-inoculation controls. The bacterial isolate was also able to colonize and develop in the rhizosphere soil of wheat after inoculation.     

小麦生长季氮素在紫色土中的迁移和淋失

利用原状回填土渗漏池研究了小麦生长季节氮素在紫色土中的移动特点和淋洗损失以及影响氮素移动和淋失的因素。结果表明,小麦生长期间氮素的移动和淋失主要以NO3^--N为主。小麦生长前期是NO3--N向下移动最强烈的时期,向下淋洗的NO3^--N没有在土壤剖面中累积,小麦收获后NO3^--N在lm土壤剖面中呈均匀分布。氮素淋失量平均为4．81kg／hm^2,淋洗损失的氮占施氮量的1．7％～3．3％。降雨量、氮肥用量、肥料品种和土壤性质影响了NO3^--N在紫色土中的移动和淋失。     

气候变化情景下海河流域水文循环变化模拟

Climate change scenarios, predicted using the regional climate modeling system of PRECIS (providing regional climates for impacts studies), were used to derive three-layer variable infiltration capacity (VIC-3L) land surface model for the simulation of hydrologic processes at a spatial resolution of 0.25° × 0.25° in the Haihe River Basin. Three climate scenarios were considered in this study: recent climate (1961-1990), future climate A2 (1991-2100) and future climate B2 (1991-2100) with A2 and B2 being two storylines of future emissions developed with the Intergovernmental Panel on Climate Change (IPCC) special report on emissions scenarios. Overall, under future climate scenarios A2 and B2, the Haihe River Basin would experience warmer climate with increased precipitation, evaporation and runoff production as compared with recent climate, but would be still likely prone to water shortages in the period of 2031-2070. In addition, under future climate A2 and B2, an increase in runoff during the wet season was noticed, indicating a future rise in the flood occurrence possibility in the Haihe River Basin.