岷江百合悬浮细胞系的建立及植株再生

 以岷江百合（Lilium regale Wils.）颗粒细小、结构松散的乳白色愈伤组织为起始材料,接种在MS（NH4NO3含量减半）+ 2.0 mg · L-1 picloram + 30 g · L-1蔗糖液体培养基上,在25 ℃黑暗条件下振荡（100 r · min-1）培养10 ~ 20 d,建立分散性好、均匀、生长迅速的悬浮细胞系。在悬浮细胞系培养过程中研究了不同参数对其生长的影响,结果表明：在40 mL培养液中接种量为0.5 g（鲜样质量）,18 d继代1次,继代时保留1/3体积的旧培养液有利于其细胞增殖。将悬浮细胞转移到1/2MS + 30 g · L-1蔗糖的再生培养基上成功获得再生植株。     

‘霞多丽’胚性细胞悬浮系的建立及植株再生

以‘霞多丽’前胚物质为试材,初步建立了‘霞多丽’胚性细胞悬浮系,并研究了不同激素及其浓度配比,不同种类及浓度的碳源以及谷氨酰胺对悬浮细胞生长的影响.结果表明:2,4-D和NOA均可以抑制胚性细胞的分化,但2,4-D更有利于细胞的增殖,最佳的2,4-D附加浓度为1 mg/L.同等浓度(0～60 g/L)的麦芽糖比蔗糖更利于细胞的生长,15 g/L为‘霞多丽’胚性悬浮细胞生长的最佳麦芽糖浓度.附加谷氨酰胺可以显著提高悬浮细胞的生长,其中以500 mg/L为最佳.     

根施多效唑对银荆籽苗生长的影响

在盆栽条件下,研究根施0、0.5、1.0、1.5、2.0、2.5、3.0 mg/L多效唑水溶液对银荆籽苗苗高、地径、全重、地上重、地下重等生长因子的影响.结果表明:多效唑对籽苗苗高的增长具有抑制作用,其中根施2 mg/L处理效果最好,苗高6.520 cm,比对照降低了18.34％.多效唑有助于提高籽苗的地径,其中根施1.5 mg/L处理效果最好,地径1.336mm,比对照提高了5.36％.全重之间呈显著差异,其中根施1、1.5 mg/L处理效果最好,全重0.246 mg,比对照提高了13.36％.地上重之间呈显著差异,其中根施1.5 mg/L处理效果最好,地上重0.133 g,比对照提高了22.02％.地下重之间呈显著差异,其中根施1.5 mg/L处理效果最好,地下重0.127 mg,比对照提高了69.33％.综合结果表明,真叶形成后根施1或1.5 mg/L多效唑水溶液最有利于银荆籽苗生长.     

Analysis of Leaf Suspension of Vehicle Using Non-linear Finite Element

This paper introduced basic concept and resolvent of nonlinear FEA, the analysis of intensity and stiffness of the rear leaf spring on SC1020 vehicle was carried out with contact nonlinear function of FEA program ANSYS, and the pre-stress distribution and pre-deformation after assembled were introduced , the stress distribution and deformation under different loads had also been presented. Thus we can calculate the mechanical and dynamic performance of leaf spring at the design stage. The result showed a great agreement with the test. It is convinced that the CAE (Computer Aided Engineering) technology can improve the design of vehicle suspension and the cost and time can be saved.     

The long-term effects on upland sheep production in the UK of a change to extensive management

Extensification (a reduction in fertilizer inputs and stocking rate of grassland) is seen as one way of increasing the conservation value and of reducing the environmental impact of upland sheep production in the UK, but little is known about the consequences of such a change. This study determines the changes in animal production over ten years following the introduction of four extensive grazing management strategies to perennial ryegrass/white clover pastures at two upland sites. Fertilizer‐free treatments were maintained with sward heights of: 4 cm (treatment 4/4U) or 8 cm (8/8U) during the whole of the grazing year, 4 cm during summer and 8 cm during autumn (4/8U) and 8 cm during summer and 4 cm during autumn (8/4U). A control treatment that received 140 kg N ha^?1 year^?1 was also maintained with a sward surface height of 4 cm (4/4F). Scottish Blackface sheep grazed all treatments. The 4/4F treatment carried the greatest number of animals (3746 grazing days ha^?1 year^?1); the 4/4U and the 8/8U treatments carried 0·73 and 0·43 of this number respectively. The number on the 4/8U treatment was similar to that on the 4/4U while the 8/4U treatment carried 1·41 of that on the 8/8U treatment (0·61 of 4/4F). Mean individual animal performance was greatest on the 8 cm swards and tended to be lowest on the 4/4F treatment. However, the 4/4F treatment produced the greatest live weight of lamb (623 kg ha^?1 year^?1) with the 4/4U producing 0·77, and the 8/8U producing 0·55, of this amount. Although there was year‐to‐year variation in agricultural output, it was concluded that the lower levels of sheep production that result from a change to extensive systems of grazing management can be maintained for at least 10 years.     

Nitrogen mineralization and water-table height in oligotrophic deep peat

Summary Peat cores, 0–60 cm depth, were taken on 14 occasions from three experimental plots where the water levels in the surrounding ditches had been artificially controlled for 14 years at 0, 20 and 50 cm below the surface. Numbers of aerobic and anaerobic ammonifying bacteria in the profile were significantly increased (P< 0.05) by lowering the water level from 0 to 50 cm. These increases occurred mainly in the surface 20 cm horizon, where 80%–90% of the ammonifying bacteria in the profile occurred. Mineral N in fresh samples, which was present almost entirely as ammonium, decreased sharply with depth below 20 cm, and on two occasions concentrations were significantly greater (P<0.05) in plots with water levels at 20 and 50 cm than in the flooded peat. Readily mineralized N, produced during waterlogged incubation at 30°C for 9 weeks, was significantly greater (P<0.05) on eight occasions in samples from plots with water levels at 20 or 50 cm than in those where the water level was at the surface. Calculations showed that the increases in N availability as a result of lowering the water-table could be attributed mainly to deeper rooting.     

四种禾草株高生长进程差异分析

研究四种禾本科草类（冷地早熟禾、星星草、紫羊茅和草地早熟禾）在西宁地区的株高生长进程。结果表明：在生育期内禾草的生长速度不一致，生长曲线呈Ｓ形；用对称Ｓ形曲线模拟和Ｌｏｇｉｓｔｉｃ生长曲线模拟后，四种禾草的Ｓ形曲线间有差异，因而生长高峰期的到来也有差异，草地早熟禾出现最早，为返青后的第３８（或３９）ｄ，紫羊茅出现最晚，为返青后的第５４（或５５）ｄ，平均生长速度和最大生长高度也有差异，冷地早熟禾最大，分别为０．５６ｃｍ／ｄ和５６ｃｍ，草地早熟禾最小，分别为０．３８ｃｍ／ｄ和３０ｃｍ。     

椪柑早期结果与树相特征相关性的线性分析

柑的早果性、丰产性与其树形结构有密切的联系。本文通过对瑞金、新干等产区实地调查，取得丰富的数据，对碰柑树冠生长量、夏梢生长量、高宽比、分枝数及裙枝数等多项因子与柑早期产量的相关性进行通径分析，揭示其线性关系，得出柑早结丰产的形成与其早期多项生产指标本质的内在联系。     

小流域治沟骨干坝系优化规划模型研究

本文分析了目前将坝高和打坝顺序及间隔年限分别进行优化的规划方法，指出了这种方法在骨干坝系优化规划方面所存在的局限性，并以甘肃平凉虎山沟流域为例，提出了统一采用动态经济方法，一次解决坝系优化规划问题的数学模型。     

回归方程的主成分估计在林业预测中的应用

讨论了林业中使用主成分估计方法克服回归模型复共线性问题。研究和分析了材积方程模型、油松林木平均高与立地环境因子回归模型中存在的复共线性，以及主成分估计方法在建立上述回归方程中的应用。