保鲜液中蔗糖浓度与瓶插深度对切花月季保鲜效果的影响

采用不同蔗糖浓度(0%,2%,3%,5%的保鲜液)与不同瓶插深度(5、8.5、12.5 cm),测定月季的瓶插寿命和花径增大量,研究2因素对瓶插月季保鲜效果的影响。结果表明:保鲜液中蔗糖浓度对月季瓶插寿命和花径有极显著影响(P<0.01);保鲜液中瓶插深度对月季瓶插寿命没有影响(P>0.05),但对其花径有极显著影响(P<0.01)。蔗糖浓度为2%,瓶插深度为5 cm时月季瓶插寿命最长,可达8.75 d;蔗糖浓度为5%,瓶插深度为12.5 cm时对瓶插月季花朵增大效果最好,达29.3 mm。     

Soil Fertility and Plant Nutrition Research Under Controlled Conditions: Basic Principles and Methodology

In modern agriculture, use of essential plant nutrients in adequate amounts and proper balance is one of the key components in increasing crop yields. Further, in developing crop production technologies, research work under field and controlled conditions is necessary to generate basic and applied information. In addition, research is very dynamic and complex due to variation in climatic, soil, and plant factors and their interactions. This demands that basic research information can only be obtained under controlled conditions to avoid or reduce effects of environmental factors on treatments. Hence, the objective of this article is to discuss basic principles and methodologies of research in soil fertility and mineral nutrition under controlled conditions. Topics discussed are soil and solution culture experimental techniques including, fertilizer application and planting, liming acid soils, experimental duration and observations, composition of nutrient solutions, preparation and sources of iron (Fe) in nutrient solutions, pH of nutrient solutions, and stable supply of nutrients in the solution culture.     

生菜无土栽培营养液配方的筛选

以日本京优生菜品种为试验材料,在日光温室内进行无土栽培试验,研究不同营养元素浓度对生菜产量的影响,得出了相应的变化规律。同时以生菜的叶片数、最大叶宽、最大叶长、最大根长、地上部鲜重为构成因素,观察不同营养液配方在生菜定值第15d、第25d、第35d的对比结果。在定植后的15、25、35d,无论是叶片数还是根长等的影响都比较显著。根据3组数据各指标的观测和记录筛选出先进的生菜栽培营养液配方。     

营养液对毛竹叶片效应的研究 Ⅰ.营养液对叶片解剖构造影响比较

对 1 996年冬施用毛竹营养液的 3块标准地和对照毛竹叶片进行解剖研究 ,结果表明施用毛竹营养液后维管束变小 ,增强了对水肥输导能力 ,机械组织较不发达 ,维管束间叶肉细胞增大 ,栅栏层中长柱细胞数明显增多 ,多环细胞层次减少 ,有利于增强光合作用 ,增加有机物质积累 ,达到高产稳产。     

甘菊水培体系的建立

为探索甘菊[Chrysanthemum lavandulifolium(Fisch. ex Trautv.)Makino]在非生物胁迫下以及营养物质代谢中精准的生理、基因表达变化机理,研究通过筛选外植体的种类和营养液的浓度,建立了甘菊水培体系。结果表明:水培中,播种苗的成活率和生根率极显著高于1年生大苗和茎段插条;在长时间的水培中,使用标准Hoagland和1.5倍Hoagland培养液,其畸形叶率极显著低于1/2和1/4Hoagland培养液,并且株高极显著高于另外2个浓度。结合科研需求,认为组培播种苗、标准Hoagland营养液是甘菊水培的最佳外植体和培养条件。     

现职干部任职教育存在的问题及对策

在现职干部任职教育的实践过程中,经过不断摸索和总结,发现存在与培养高素质新型军事人才不相适应的诸多问题,通过归因分析,提出了优化师资队伍、课程设置特色化、创新教学方法和手段、强化管理的服务性功能、完善激励机制和保障机制等解决方法。     

龙翅海棠的水培生长试验研究

用不同浓度的吲哚乙酸、萘乙酸和吲哚丁酸处理龙翅海棠的插条,测定了不同条件下的生根情况,另以氮、磷、钾比例不同的3种营养液水培龙翅海棠,筛选最佳配方.结果表明:浓度为100 mg//L的吲哚丁酸处理插条2 h可显著提高其根长和根鲜重;从叶片和根系生长及植株整体状况考虑,营养液氮、磷、钾的最佳比例为6:1:7,该比例下植株根系生长旺盛、根毛丰富、新叶生长快,应为生产首选.     

高职院校产学结合：问题、原因、对策思考

高职院校产学结合至今仍基本处于浅层次的初级阶段和中层次的起步阶段，存在着产学合作机制不够完善、产学合作链条尚未完全形成、产学合作各主体定位不够清晰以及合作层次偏低、国际化程度不高等问题。文章对相关问题及其成因展开分析，并提出了相关对策思考。     

Arsenic speciation in xylem exudates of rice growing in arsenic-contaminated soil

Rice has a much enhanced arsenic (As) accumulation compared with other cereal crops. How As is transported in xylem exudates of rice growing in soil remains unknown. We quantified the chemical species of As in xylem exudates of rice growing in arsenic-contaminated soil (62.5 mg As per kg soil) under flooded and aerobic conditions. In the aerobic treatment, the predominant species of As in the xylem sap was arsenate [As(V)], accounting for 64–88%, and the remainder was arsenite [As(III)]. In the flooded treatment, dimethylarsinic acid (DMA) was detected in the xylem sap besides As(III) and As(V), and the percentages of the three species As was 11–20%, 26–77%, and 12–54%, respectively. As speciation in the soil solution was dominated by As(V) under aerobic conditions, and dominated by As(III) under flooded conditions. DMA was detected at low concentrations in some of the flooded solution samples. Our results show that As speciation in the xylem sap differs in different water management regimes and correlate with As speciation in the soil solution strongly.     

新形势下地方本科院校农学专业实践教学存在的问题及对策

针对新形势下地方本科院校农学专业实践教学过程中存在的问题,积极探讨其解决途径,旨在促进该专业实践教学进一步发展,提高农学专业学生综合素质.