施肥对红三叶群落营养元素含量和积累量的影响

本文研究了施肥对红三叶群落地上部和地下部 1 0种营养元素的影响 ,结果如下 :( 1 )从含量看 ,施氮肥后 ,地上部B明显降低 ,地下部B明显升高 ;施磷肥后 ,地上部N、B显著下降 ,地下部K、P、N上升幅度较大。 ( 2 )就积累量而言 ,施氮肥后 ,地上部大多数元素增高 ,地下部多数元素降低或无变化 ;施磷肥后 ,无论地上部还是地下部 ,大多数元素均有所增高     

植物在水分胁迫下脯氨酸积累的研究─—Ⅳ关于植物体内脯氨酸积累的直接触发因子

依据干旱胁迫下数种植物幼苗体内游离脯氨酸、叶气孔、叶水量的变化，剖析了植物与环境因子、气孔因子、氧气因子、酶因子及能量因子之间的相互依存关系，提出了ＰＲＯ积累系统（ＰＡＳ）。认为水分胁迫下植物体内ＰＲＯ的大量积累是氧化受抑和合成受激共同调控的结果。氧气最有可能为直接触发因子。     

Stoffbildung, CO2-Gaswechsel, Kohlenhydrat- und Stickstoffgehalt von Winterweizen bei erhöhter CO2-Konzentration und Trocken-streß

Dry Matter Production, CO₂ Exchange, Carbohydrate and Nitrogen Content of Winter Wheat at Elevated CO₂ Concentration and Drought Stress
Methods of mathematical modelling and simulation are being used to an increasing degree in estimating the effects of rising atmospheric CO₂ concentration and changing climatic conditions on agricultural ecosystems. In this context, detailed knowledge is required about the possible effects on crop growth and physiological processes. To this aim, the influence of an elevated CO₂ concentration and of drought stress on dry matter production, CO₂ exchange, and on carbohydrate and nitrogen content was studied in two winter wheat varieties from shooting to milk ripeness. Elevated CO₂ concentration leads to a compensation of drought stress and at optimal water supply to an increase of vegetative dry matter and of yield to the fourfold value. This effects were caused by enhanced growth of secondary tillers which were reduced in plants cultivated at atmospheric CO₂ concentration. Analogous effects in the development of ear organs were influenced additionally by competitive interactions between the developing organs. The content and the mass of ethanol soluble carbohydrates in leaves and stems were increased after the CO₂ treatment and exhausted more completely during the grain filling period after drought stress. Plants cultivated from shooting to milk ripeness at elevated CO₂ concentration showed a reduced response of net photosynthesis rate to increasing CO₂ concentration by comparison with untreated plants. The rate of dark respiration was increased in this plants.     

Quasi-non-linear fracture mechanics analysis of splitting failure in simply supported beams loaded perpendicular to grain by dowel joints

A quasi-non-linear fracture mechanics model based on beam on elastic foundation theory is applied for analysis of the splitting failure of dowel joints loaded perpendicular to grain. Simply supported beams symmetrically loaded by two dowels are considered, and the effects of edge distance, dowel spacing, and distance between dowels and supports are accounted for. The foundation modulus used in the beam on elastic foundation model is chosen so that the perpendicular-to-grain tensile strength and fracture energy properties of the wood are correctly represented. This ensures that a conventional stress analysis and failure criterion lead to the same solution as the compliance method of fracture mechanics. A semiempirical efficiency factor is proposed to account for the influence of the total beam depth, which does not enter the beam on elastic foundation model, but the effect of which is evident from tests. It is shown that the so-called Van der Put/Leijten model, which recently has been adopted in Eurocode 5, appears as a special case of the model presented. Tests on simply supported beams with a single dowel joint at midspan are compared with the theoretical predictions. Various edge distances, beam depths, and spans were tested.     

改善E1级胶合板用UF胶粘剂预压性能的研究

利用氧化淀粉在树脂合成后期、API在调胶时加入分别对脲醛树脂进行改性，探讨改性UF对胶合板预压强度的影响。采用正交实验法对比改性后胶合板的预压性能和改性后胶合板的甲醛释放量的变化。结果表明：随着API量的加大，胶合板的预压性能得以提高；而氧化淀粉改性后则随着量的加大，一定范围内胶合板的预压性能得以提高，加入量继续加大后反而下降。     

Physiological Basis of Irrigation Scheduling for Seed Production in Egyptian Clover Syn. Berseem (Trifolium alexandrinum L.) Crop

A field experiment was conducted to find out the critical physiological stages of irrigation schedules inducing better growth, physiological efficiency and seed yield potential of berseem ( Trifolium alexandrinum L., Var. S-99-1). For this purpose eight irrigation treatments were made comprised of four treatments of three irrigation (W₁, W₂, W₃ and W₄), three treatments of four irrigation (W₅, W₇ and W₈) and one treatment of five irrigation (W₆) at various physiological stages i. e. regeneration, flower initiation, full bloom, seed initiation and advance seed development stage.
Thus based on the experimental results the physiological role of watering in berseem seed production could be discussed as:
With-holding of irrigation either at regeneration or at full bloom stage developed potential water stress in plants as indicated by high proline content of irrigation treatments — W₄, W₁ and W₇; and further brought out disturbance on the formation of carotene, synthesis of water soluble sugar and translocation of sugar towards reproductive organs during grain development stage. These stresses adversely affected the plant growth and flowering behaviour. The irrigation at seed initiation stage increased the seed yield. Continuous irrigation did not appear to be useful. Thus it can be concluded that irrigation at three critical physiological stages i. e. regeneration, full bloom and seed initiation was found to be essential for obtaining potential seed yield of berseem.     

苜蓿施用污泥效果的研究Ⅰ对苜蓿生长及元素含量的影响

将兰州市七里河污水处理厂生活污泥施用于人工种植的新疆大叶苜蓿草地，探讨了不同施用量对苜蓿生长及各元素含量的影响。研究结果表明，施用1.0-2.0kg/m^2污泥，苜蓿地上生物量显著增加，第一年增产23％－31％，第二年增产15％－31％。施用污泥苜蓿地上和地下部组织中N，P，Ca,Mg和Mn的含量总体呈增加趋势，Fe含量显著增加，而K和重金属元素Ni、Pb、As和Hg的含量与对照无显著差异，Zn和Cu的积累增多，但地上部组织中重金属元素均未超过植物中的平均含量，施用污泥未对新疆大叶苜蓿造成重金属污染。     

硅藻土杀虫剂处理后储粮害虫成虫体重减轻与死亡

研究了硅藻土杀虫剂“普粮泰”对米象、谷蠹、玉米象和锯谷盗成虫体重的影响。在30±1℃、65%±1%RH条件下,试虫分别在0.5~8 g/m2的粉剂药膜上处理1天,它们(顺序同上)的平均体重分别减少了0.1、0.4、0.2和0.2 mg/头,在相同条件下培养7天后,它们的平均死亡率分别为52%、100%、97%和100%。在25±1℃、65%±1%RH条件下,经过1 g/m2粉剂药膜处理锯谷盗1天后,在原条件下不提供食物保持3天,平均每头锯谷盗体重比对照减少了0.2~0.3 mg/头,平均死亡率达到76%。由此可见,硅藻土杀虫剂处理的储粮害虫成虫体重明显减少(P<0.05),死亡率很高,说明硅藻土杀虫剂可能破坏了试虫体壁保持体内水分的蜡质层,从而引起锯谷盗失水干燥而死。     

农户防鼠密闭储粮袋

筛选出了防鼠效果良好的微胶囊化的放线菌酮及其最佳使用浓度，并用其制出了用维纶聚氯乙烯双面涂塑为材料的具有良好防鼠性能、防潮、密封性好，便于防治害虫、重量轻、容量大、成本低的农户储粮袋。