痕量灌溉管不同埋深对日光温室沙培黄瓜的影响

以微喷灌溉(CK)为对照,研究痕量灌溉管在沙培中不同埋深对日光温室春季黄瓜生长、产量和水分生产效率等的影响.结果表明,T3处理(25cm)的黄瓜生长与CK(微喷)相比受到显著抑制,T1 (5cm)、T2(15cm)处理黄瓜生物积累量、叶片净光合速率、果实品质与CK相比均有所提高,不同处理间叶片电导率、MDA、根系活力差异不显著,T1、T2、T3处理沙子含水量均低于CK;T1处理的产量比T2处理提高了1.9％;与CK相比的T1、T2处理水分生产效率分别提高50.9％、60.0％.分析表明,日光温室沙培黄瓜栽培中痕量灌溉管埋设深度为5 cm最佳.     

Comparison of Free Air Space Test Methods

Air space within a compost material can be measured using several methods. This project, focusing on bulking materials, compared five air space (AS) test methods: particle density (PD) method, modified PD (MPD) method, air pycnometer (AP) method, modified air pycnometer (MAP), and a quick method. There were significant differences between results obtained using the different tests. PD and MAP methods yielded results representing total air space (TAS), while the AP and MPD methods yielded values which were thought to represent free air space (FAS). The Quick method resulted in AS values dramatically different from the other methods, and further development and validation of the method was recommended. The MPD was found to be unsuitable for samples containing fine material, such as biosolids. Both the PD and the MAP tests were precise; however, results were biased to TAS values. This was illustrated through the similarity between AS values measured by the two tests and the predicted TAS. The MAP was the simplest method and was recommended for use with compost samples. Strong linear correlations were observed between TAS and bulk density (BD; kg m^?3: TAS = 100 – 0.096*BD (R²=0.98) for PD and 100 – 0.090*BD (R²=0.90) for MAP. The effect of storage time on FAS, TAS, and moisture content was examined in this study. Straw samples were stored for a month and showed no change in the physical properties. Woodchip samples were stored for over 5 months. A slight change in both FAS and TAS was observed, but the differences were minor compared to variations induced by different particle sizes and moisture levels.     

油松容器苗枯梢症的预防

在玛可河林业局育苗基地油松容器苗的培育过程中,发现有枯梢症发生,通过分析发生的主要原因,对油松枯梢症采取了预防措施,取得了明显效果.     

Relative contributions of sedimentation and impaction to deposition of particles in a crop canopy

Lycopodium spores were released steadily into the air during 20–30 min from a line source positioned within a wheat crop. The spores were trapped on sticky strips held at angles, π, of 0, 30, 60 and 90° with respect to the horizontal and oriented to face the mean wind direction and on sticky, vertical glass rods. The aerial spore concentration, C, was measured by small suction traps. Deposits of the spores on wheat leaves were obtained from sections of leaves whose posture in the canopy was nearly horizontal, nearly vertical, or at angles between 30 and 60°. Number of spores per m² for all trapping surfaces were obtained by counting under a microscope. Experiments were conducted on seven different days, encompassing friction velocities, u^*, of 0.27–0.50 m s⁻¹. The rate of deposition on angled surfaces, D(π), was given approximately by D(θ) = D(0) cos (θ) + D(90) sin (θ), where D(0) and D(90) were the observed rate of deposit on horizontal and on vertical surfaces, respectively. Below mid-canopy height, inertial impaction of spores was negligible, so that D(90) = 0 for all the trap surfaces. There, D(0) was mainly due to sedimentation and was very nearly equal to v_s·C, where v_s is the settling speed of the spore in still air. Near the top of the canopy, deposition on sticky surfaces was enhanced by inertial impaction and turbulent deposition, so that D(0) was about twice that expected from sedimentation and D(90) was about five times larger than expected from inertial impaction at the mean wind speed. Nevertheless, considering the vertical distribution of leaf area and the angles of leaves in a wheat canopy, the rate of deposition of spores for the entire depth of a wheat canopy can be calculated with a probable underestimation of only 20% by simply assuming sedimentation on horizontally projected area and impaction on vertically projected area.     

The elemental composition of asteroid 433 eros: results of the NEAR-shoemaker X-ray spectrometer

We report major element composition ratios for regions of the asteroid 433 Eros imaged during two solar flares and quiet sun conditions during the period of May to July 2000. Low aluminum abundances for all regions argue against global differentiation of Eros. Magnesium/silicon, aluminum/silicon, calcium/silicon, and iron/silicon ratios are best interpreted as a relatively primitive, chondritic composition. Marked depletions in sulfur and possible aluminum and calcium depletions, relative to ordinary chondrites, may represent signatures of limited partial melting or impact volatilization.     

披针叶黄华生物碱成分研究

采用 GC- MS联用分析技术从披针叶黄华总生物碱中分离鉴定出 12个喹喏里西啶生物碱 ,即无叶豆碱 ,N-甲基金雀花碱 ,金雀花碱 ,白羽扇豆碱 ,黄华碱 ,臭豆碱 ,N-甲醛基金雀花碱 ,Dodecahydro- 7,14 -methanodipyrido[1,2 - a:1′,2′- E][1.5 ]diazocine,Pyridine1- acetyl- 1,2 ,3,4 - tetrahydro- 5 - (2 - piperdinyl) ,7,14 -Methano- 2 H,6 H- dipyrido[1,2 - a:1′,2′- e][1,5 ]diaz,1,1- Dim ethyl- 3- (2 - nitrophenyl) ,7,14 - Methano- 4 H,6 H-dipyrido[1,2 - a:1′,2′- e][1,5 ]diaz。后 5种化合物为首次从该植物中鉴定     

日光温室CO2自动施肥系统的研制

研制了具有自动化特征的CO2施肥系统及其技术，并对该项技术的施肥效果进行了试验。结果表明：利用此装置，日光温室内的CO2浓度均匀程序较好，经济上可行，且气源来源广泛，长期施用对大气和土壤无污染，该项施肥技术加速了中国温室生产技术与世界发达国家接轨的进程。