Pre-conditioning ornamental plants to drought by means of saline water irrigation as related to salinity tolerance

This study examines the feasibility of using saline irrigation water for commercial pot cultivation of three ornamentals: Calceolaria hybrida, Calendula officinalis and Petunia hybrida. Two saline treatments were assayed: irrigation with low saline tap water (electrical conductivity = 1.16 dS m⁻¹), and irrigation with a high saline solution of NaCl 100 mM + CaSO₄ 10 mM + MgSO₄ 2.5 mM (electrical conductivity = 12.5 dS m⁻¹). When the control plants reached marketable size the watering was stopped and the plant response to drought was studied. Petunia and Calceolaria were tolerant to salinity. Petunia saline-treated plants reduced their growth slightly and increased N and chlorophyll contents in the leaves. Calceolaria experienced a strong reduction in growth and a delay in flowering but no toxicity symptoms or mortality was recorded. These species were moderate NaCl accumulators. Calendula was sensitive to salinity: 16% of the plants died and the surviving ones experienced a heavy reduction of growth, a decrease in chlorophyll and a large accumulation of NaCl in the leaves. Saline pre-conditioned plants of Calceolaria and Petunia were tolerant to drought. In these plants, leaf water content and, specifically, leaf relative water content were sustained longer than in non-pre-conditioned plants throughout the drought period. In Calendula, leaf relative water content decreased at the same rate in pre-conditioned and non-pre-conditioned plants. Consequently, salinization did not confer drought resistance upon this species. Possible factors determining the tolerance to drought in saline pre-conditioned plants are discussed.     

Effects of urea formaldehyde foam soil amendment on growth and response to transient water deficit stress of potted Flindersia schottiana saplings

Hydrocell™is a urea formaldehyde resin foam (UFRF) product used as a soil amendment. It is proposed to improve the physicochemical properties (viz. water relations and aeration) of the plant root zone. Flindersia schottiana is a tree species used in the ornamental horticulture industry. This study investigated the potential of Hydrocell™ [0–50% (v/v) incorporation rates] to promote growth of F. schottiana saplings during containerized nursery production in composted pine bark medium. The growth response of the potted saplings to transient water stress was also assessed. In addition, growth of F. schottiana saplings potted into three different soil types (sand, loam, clay) was assessed in the presence and absence of 30% (v/v) Hydrocell™. Under well-watered conditions in composted pine bark, Hydrocell™ treatments enhanced sapling leaflet numbers, with 30% (v/v) being the most beneficial treatment. However, no consistent significant differential effects of incorporation rate on either plant height or stem diameter were recorded. Extended time to wilting upon withholding irrigation was achieved, with the optimum Hydrocell™ rate being 10% (v/v). Among the three soil types compared, use of 30% (v/v) Hydrocell™ resulted in improved growth of potted F. schottiana saplings in the sand and loam soils, but not in the clay soil. These findings suggest that the UFRF, Hydrocell™, holds limited promise as a soil amendment for trees in the nursery phase. Optimum incorporation rates (v/v) would need to be determined for individual media types, specific irrigation regimes and individual taxa.     

刨花对流干燥过程的传热传质研究动态

详细介绍并归纳多孔介质与木材领域内的传热传质理论研究概况,从中寻找出适合研究刨花对流干燥过程传热传质的方法.经过理论分析,提出可根据非平衡热力学理论和相平衡理论,建立一个描述刨花对流干燥时刨花外部对流传热传质和内部热、湿迁移过程的非平衡热力学模型.     

农业科技期刊与新媒体融合路径探讨

结合农业科技期刊的特点,分析了农业科技期刊与新媒体融合的影响因素,探讨了农业科技期刊与新媒体融合路径,以期推动农业科技期刊转型升级,促进农业科技期刊发展。     

不同轻基质对杉木无性系组培苗生长的影响*

以杉木（Cunninghamia lanceolate）无性系组培苗为材料,选用4 种育苗基质,采用单形重心 混料试验设计,探究不同轻基质种类及配比对苗木质量的影响。结果表明,基质种类和配比方式对杉木 无性系组培苗保存率和苗木生长有较大影响,基质中泥炭土所占的比例应控制在20% 左右,并配合珍珠 岩或蛭石一起使用,椰糠可不加或少加。总根长、总根表面积、总根体积、根冠比、平均根直径等根系 形态参数是评价杉木无性系轻基质容器苗质量的重要指标。利用隶属函数值对不同配方的育苗效果进行 综合评价,筛选出泥炭土20%+ 珍珠岩40%+ 蛭石40% 的9 号配方为最佳组合,移栽6 个月后苗木保存 率为91.70%,苗木高/ 径生长明显,根系发达,苗木综合质量明显优于黄心土容器苗。     

栽培基质对神秘果种子萌发及幼苗生长的影响

不同的混合基质对神秘果种子的萌发和生长的影响存在差异,其中以处理3（土：椰糠=2：1）综合效果最好。发芽率达90％以上,虽然其地上部分的生长稍次于其它处理,但其地下部分的生长明显优于其它处理。对种子根系的萌发与生长有较好的作用,特别是干物质的积累远远大于其它处理。土壤中加入适当椰糠,对种子的萌发和生长具有明显的促进作用。     

新媒体环境下大学生舆情教育的应对策略探析

近年来,舆情已成为社会学、心理学、政治学等学科的研究热点,大学生舆情因大学生群体的特殊性,表现出与普通舆情较大的差异性。随着新媒体时代的到来,信息高速发展,对大学生的思想冲击越来越大,共青团作为引导大学生思想动向的组织,必然担负起引导大学生舆情的重任。本课题从新媒体环境的特点出发,对大学生舆情的类型、特点及其传播规律进行了分析,并探讨新媒体环境的特殊性对大学生舆情的影响,共青团组织如何在新形势下提高大学生舆情引导模式,建立快速干预机制,以帮助大学生树立健康的人生观、价值观。     

Moisture Evaporation from Bare Soils

This study offers a method of calculationof soil moisture evaporation from baresoils, which is based on the theory ofexchange processes in porous media. Thismethod has taken into account basiccharacteristics of porous media, as wellthe states of soils and the weatherconditions under which soil moistureevaporation occurred. Calibration of modelparameters has been carried out. The modelwas verified with natural measurement dataof different regions of the former SovietUnion.     

食用菌培养料搅拌机的设计与试验

在比较和研究现有各种物料混合搅拌机的基础上，设计了一种食用菌培养料搅拌机。对转速、混合时间和充满系数进行了试验研究，通过三因素三水平的正交试验及一次回归正交试验设计确定了各因素的最佳组合，建立了各指标的数学模型。