油松嫩枝扦插育苗试验

用油松嫩枝作插穗，在粗河沙中扦插育苗，插后先形成愈合组织，后从愈合组织处生根，皮部不生根．以浓度１０００μｇ／ｇ萘乙酸处理生根率最高，为５７．７％，移栽成活率为９４．９％。     

东革阿里组织培养初报

通过对东革阿里不同生长时期的枝条进行离体培养,结果表明:老化的枝条较难进行消毒,当年萌发的新枝条消毒相对易些;能诱导出东革阿里愈伤组织的培养基是MS+6-BA0.5mg/L+NAA0.01mg/L+3%蔗糖。     

叶顶形状对轴流泵空化性能的影响

轴流泵叶轮与转轮室之间间隙内的泄漏流动与主流相互掺混形成的泄漏涡是导致轴流泵叶顶空化的重要原因。为研究合适的叶顶形状来控制和改善叶顶泄漏空化,通过高速摄影空化试验,比较了试验结果和数值计算结果,验证了本次数值计算的正确性。再在原始平面叶顶方案的基础上,通过数值计算,分别研究了3种叶顶形状(倒圆叶顶、斜切叶顶以及倒圆斜切叶顶)对轴流泵叶顶空化的影响。叶轮水体采用结构网格划分,以便精确捕捉间隙区域的流场特性。结果表明:倒圆叶顶和倒圆斜切叶顶方案的扬程和效率都有所下降,但斜切叶顶有所升高。虽然倒圆叶顶消除了角涡空化,但泄漏涡空化加剧;而斜切叶顶得到的结果却与之相反,且斜切叶顶的间隙内会有漩涡空化产生;相比之下,倒圆斜切叶顶的角涡空化和泄漏涡空化都得到了较好的控制。根据研究结果,建议在满足外特性性能要求的情况下,采用倒圆斜切叶顶方案可以较好地控制轴流泵的叶顶空化。     

利用蚕豆根尖细胞微核技术对新疆伊犁河水质检测

[目的]研究新疆伊犁河水域的不同位点的水质污染程度。[方法]利用蚕豆根尖微核技术对新疆伊犁河水域的30个水样进行动态监测和评价。[结果]各样点MCN％砑,对照组相比差异极显著（P〈0．01）,30个水样点中有12个水样点无污染（P,值在0～1．5）;10个水样点轻度污染（P,值在1.5～2．0）;8个水样点中度以上污染（H值2．0以上）。[结论]新疆伊犁河水质受到不同程度的污染,部分区域中度以上污染,应及时加以治理。     

甘薯茎尖脱毒及组培快繁技术

[目的]研究甘薯茎尖分生组织的分化培养基配方及快繁培养的影响因素。[方法]以甘薯茎尖作为外植体,总结出茎尖分化培养前的灭菌方法,筛选出适宜的分化培养基配方、快繁培养基配方以及影响快繁的各因素。[结果]75%的乙醇30 s+0.1%升汞10 min能取得较好的灭菌效果,降低污染率;适宜的茎尖分化培养基配方为:MS+0.5 mg/L 6-BA+0.2 mg/L NAA+0.25 mg/L GA3+10 mg/L病毒唑;快繁培养基配方为:Ms+0.1~0.2 mg/L NAA+2 mg/L泛酸钙;适宜的糖用量为30 g/L;培养条件为温度28℃、光照强度2 000lx、光照时间16 h/d时脱毒苗茎段生根较快,侧芽萌发后节间适中,有利于提高繁殖系数。[结论]为脱毒苗工厂化生产提供技术支持。     

轴流泵运行工况和叶顶间隙对叶顶泄漏涡轨迹的影响

采用SST k-ω湍流模型模拟和旋涡强度方法,对某一轴流泵模型泵叶轮叶顶区流场和叶顶泄漏涡轨迹进行了数值计算,分析了运行工况和叶顶间隙两个因素对轴流泵叶顶泄漏涡运动轨迹的影响.数值模拟结果表明,随着流量增大,轴流泵叶顶泄漏涡的涡核轨迹起点由叶尖向叶片翼型中部逐渐移动.随着流量的增大,叶片流道内的流动方向发生偏移,叶顶泄漏涡在主流的卷吸下,运动轨迹随之变化,涡轨迹线的斜率受叶轮内主流的影响而变大.随着叶顶间隙增大,泄漏涡的卷吸程度逐渐增强,影响范围增大,涡核的起点由叶片前缘逐渐向后缘移动,且涡核的压力逐渐降低,因此在大间隙时涡带更易出现空化现象.当叶顶间隙达到1.5 mm时,轴流泵在0.9Qd工况附近出现驼峰现象,说明叶顶泄漏涡对驼峰区不稳定流场具有重要的影响.     

Responses of Root Growth to Moderate Soil Water Deficit in Wheat Seedlings

Abstract

In the field, plants show better root growth in drying soil than in wet soil. However, the root growth enhancement has not been demonstrated clearly in the laboratory. In this study, the root growth response of wheat seedlings to moderate soil water deficits was characterized quantitatively in an environment-controlled chamber. Germinated seeds of wheat were grown for 15 days in the soil with a water potential ranging from field capacity (FC) to approximately –0.08 MPa. Theleaf area decreased with reduction in soil water potential. By contrast, the root surface area increased upon reduction ofthe soil water potential to –0.04 MPa while it decreased significantly in soil with a water potential of –0.08 MPa. The increase in surface area was obvious in the roots with a diameter of 0.2 to 0.4 mm and larger than 0.7 mm. Root weight increased with the reduction of soil water potential to –0.04 MPa. While specific root length decreased significantly with the reduction of water potential to –0.06 MPa, the specific root surface area did not. Assimilatestransported from shoot might be used in roots to increae the surface area mainly by increasing the diameter rather than the length in response to a moderate soil water deficit in wheat seedlings. This might result from the drought tolerance mechanism of osmotic adjustment in roots.     

Tree Mortality,Needle Biomass Recovery and Growth Losses in Scots Pine Following Defoliation by Diprion pini (L.) and Subsequent Attack by Tomicus piniperda (L.)

Tree mortality and growth losses following insect defoliation are poorly documented in Scandinavia. In 1990-1991, Diprion pini (L.) caused extensive defoliation to Scots pine in Lauhanvuori national park and surrounding areas in south-western Finland. Most trees lost all their foliage in 1990. In 1991, the outbreak area was sprayed with diflubenzuron (Dimilin®), except in the national park, where trees were severely defoliated again. No further defoliation occurred in 1992. In spring 1993, sprayed trees had ca 30% foliage, whereas unsprayed trees on average carried less than 10% of full foliage. The latter trees were susceptible to attack by Tomicus piniperda (L.), whereas the former largely escaped beetle attack. Beetle attacks peaked in 1993, and depletion of suitable host trees probably terminated the beetle outbreak in the area. Two years of severe defoliation resulted in substantial tree mortality and growth losses. In spring 1997, these unsprayed stands had suffered a ca. 50% loss in basal area which was mainly because of mortality, and about half of the dead trees had been attacked by T. piniperda. Surviving trees had ca 50% of full foliage, and radial growth had still not recovered. Basal area growth was reduced by 40-70%, depending on the amount of foliage left after the second year of defoliation. In contrast, tree mortality and beetle attack in the sprayed stands were negligible, and these trees had recovered full foliage and radial growth by spring 1997. Thus, one year of total defoliation resulted in an estimated loss in basal area growth of approximately 30% during ca. 5 yrs. In conclusion, the spraying operation was economically justified, as it prevented substantial tree mortality and reduced growth losses.     

Testing Polarization Measurements with Adjusted View Zenith Angles in Varying Illumination Conditions for Detecting Leaf Orientation of Wheat Canopy

Abstract:

The previous work revealed that the polarization of light reflected from heading wheat canopies allowed the detection of changes in the canopy structure, i.e., the leaf inclination angle. Accordingly, in order to improve measurement accuracy in this study we examined the effects of the solar zenith angle (= 90º–solar elevation) and weather conditions at the time of polarization measurements for the light reflected from wheat canopies that were fertilized by different means. We measured polarization in the 660 nm spectral band from the heading canopies of wheat, which were grown in plots fertilized with a basal dressing and then top-dressed at the jointing and booting stages. The radiometric measurements were carried out at various solar zenith angles: 22º–41º on two proximal days, one overcast and the other clear. An empirical method for the adjustment of view zenith angle, based on the solar position at the time of measurement, was effective for the measurement of the degree of polarization (i.e., ratio of the polarized part of reflected light to the total reflected light energy) to eliminate interference due to the change in solar zenith angle. Although the mean values of polarization degree measured in overcast conditions were significantly lower than those measured under clear conditions, the plots top-dressed at the jointing stage could be detected via the polarized reflected light measured under both conditions of illumination.     

控制灌水对梨幼树枝条生长和成花的影响

以3年生梨幼树为试材,研究了4种不同灌水处理对梨幼树枝条生长和花芽形成的影响。结果表明,在冬季一次灌水(250m~3/亩)的基础上,减少土壤供水可有效地控制新梢长度和粗度,缓和树势,增加花芽数量。减少土壤供水可使幼树总生长量轻微下降,主干生长减弱,树冠长梢比例下降,中、短梢比例增加,单位主干横截面积上的花芽数明显增加。生长季节控制灌水,可节约灌水量、扩大灌溉面积、并能促使梨幼树早期结果。