Effect of Water Status on Leaf Angle and Leaf Movement in Wheat

Water stress was imposed by watering withholding or application of PEG during the period following ligule emergence of Hag leaves or fifth leaves. Treatment reduced markedly the downward rotation of these youngest fully expanded leaves, and the angle finally reached. Leaf angle changes appear to be sensitive indicators of water shortage in wheat.     

水稻根系分布与叶角关系的研究初报

1983—1984年,通过群体水培、土培试验,在控制水稻根系不同分布空间形状情况下,研究了叶角与根系分布的关系,其结果主要表现如下:1.根系分布较深且多纵向时,叶角较小,叶片趋向于直立;根系分布较浅且少纵向时,叶角较大,叶片趋向于披垂。2.叶角的大小同时受叶片大小的影响,根系分布较浅且少纵向时,较大的叶片更易披垂,叶角更大,     

Cotyledon angle as a predictor of growth rate of cucumber plant

Summary Experiments conducted in the greenhouse and in the field indicated that plants produced from seedlings of Cucumis sativus L. which displayed their cotyledons in an upward position grew faster than plants which displayed their cotyledons in a downward position. Cotyledon angle was not a function of seed size nor seedling weight at 10 days after planting. An increase in plant height, node number, and fresh weight at later growth stages was associated with an upward cotyledon angle and persisted until time of harvest. Anthesis tended to occur later in plants having a downward cotyledon angle. The number of pistillate flowers was greater in plants with an upward cotyledon angle compared to those with a downward cotyledon angle. Differences in yield (fruit number) were not associated with cotyledon angle.Paper No. 5432 of the Journal Series of the North Carolina Agricultural Experiment Station, Raleigh, NC. The use of trade names in this publication does not imply endorsement by the North Carolina Agricultural Experiment Station of products named, nor criticism of similar ones not mentioned.     

Improvement of durum wheat-plant type,yield potential,and adaptation

Summary Improvement of durum wheat at the International Maize and Wheat Improvement Center (CIMMYT) was achieved by exploiting the variability of the tetraploid species in large numbers of combinations, and multi-location testing of germplasm on a world wide base. High yielding, widely adapted durums with short straw, good fertility, and adequate earliness were selected for distribution to major durum growing countries. Present attempts to improve durum wheat are directed at adjusting agronomic traits such as leaf angle and straw strength, and increasing spike fertility and spike size, thereby reaching higher grain numbers per unit area and higher yield potential. Diversification of the developmental pattern and incorporation of drought tolerance aim at further widening adaptation.     

Inheritance of leaf angle in Triticum aestivum L.

Summary A 6×6 diallel was prepared to study the inheritance of leaf angle in T. aestivum L. Genetic analysis in terms of diallel cross parameters and graphic analysis indicated the control of additive gene effects in the expression of this character. The results of F₁ analysis were supported by the analysis of F₂ data.     

外掺植物纤维对冻融作用下植被混凝土抗剪强度的影响

[目的]研究外掺2种植物纤维对冻融作用下植被混凝土抗剪强度的影响,为植被混凝土生态防护技术在高寒地区的应用提供科学依据。[方法]参考相关标准(GB/T50082-2009)中的慢冻法,采用2因素3水平全面交叉试验开展研究。[结果]未掺植物纤维的植被混凝土,冻融后黏聚力显著减小,内摩擦角变化不明显。掺入植物纤维可使经受5次冻融循环作用后植被混凝土的内摩擦角平均增加5°左右,并且随植物纤维掺量的增加,内摩擦角变化无明显规律,黏聚力则呈先增加后减小的趋势。表明纤维加筋对黏聚力的贡献存在临界掺量。棕纤维掺量对黏聚力的影响比黄麻纤维掺量更为敏感。[结论]外掺植物纤维可有效改善植被混凝土抵抗冻融破坏的能力,棕纤维和黄麻纤维的建议掺入比为0.6%和0.6%,具备推广应用前景。     

基于理想传动比的主动前轮转向控制

针对目前汽车主动前轮转向系统缺少对理想传动比规律研究的问题,建立线性二自由度车辆模型、主动前轮转向系统模型,以及轮胎模型;设计固定横摆角速度增益下的主动前轮转向系统理想传动比规律,提出基于该规律的主动前轮转向附加转角闭环控制策略,并对提出的控制策略进行仿真分析和试验验证。结果表明:基于理想传动比的前轮主动转向附加转角控制策略可有效保证车辆在低速时横摆角速度响应幅值变大,车辆具有较好的操纵性;高速时横摆角速度和质心侧偏角响应的幅值均变小,车辆具有较好的稳定性,有利于车辆获得较为理想的转向品质。研究结果可为主动前轮转向系统的设计与开发提供理论基础。     

微喷带单孔喷水量分布的基本特征研究

微喷带是一种新型的节水灌溉设备，该文根据其灌溉特点，设计了研究微喷带喷水量分布的试验装置，在此基础上建立了水量分布的测试方法。通过试验分析了喷水量分布的基本特征，为进一步研究微喷带的灌溉性能提供参考。     

泥石流与主河交汇的试验研究

泥石流入汇主河属于复杂的非牛顿流体与牛顿流体汇流问题,由于其机理的复杂性,一直缺少这方面的研究。本文在试验的基础上,分析了泥石流入汇主河后,汇口附近各水力参数的变化规律。探讨了泥石流入汇后下游水位相对壅高与流量比以及交汇角的关系,得出相对壅水高度随流量比及交汇角的增大而增大的结论。分析了交汇口附近淤积量及淤积率与流量及流量比的关系。30°,60°和120°交汇角情况下,淤积量总体趋势是随支流流量及流量比的增大而增大,淤积率随总流量增大而减小,在主支流量相当时出现最大值;90°交汇时,淤积量随支流流量及流量比的增大而减小,淤积率随总流量增大而增大,在主支流量相当时出现最小值。     

聚合物基/稻壳粉复合材料的表面改性研究

使用JC2000A型接触角测量仪测试并研究了蒸馏水和甘油两种液体在稻壳粉填充聚乙烯(PE)、聚丙烯(PP)、聚氯乙烯(PVC)复合材料表面的接触角.研究表明:通过酸碱处理可明显改变接触角及其随时间变化的规律;其中效果最好的是以水作为探测液时,经酸处理后的PE/稻壳粉复合材料.通过方差分析得知表面改性处理方式对接触角有相当显著的影响.