基因×环境互作下杂交粳稻上部三叶形态性状遗传效应分析

利用3个粳稻BT型不育系和6个粳型恢复系配制不完全双列杂交组合,采用基因×环境互作下加性-显性-上位性遗传模型,分析杂交粳稻上部三叶形态性状的遗传效应.结果表明:剑叶面积主要受基因加性效应控制,剑叶宽、倒二叶宽、倒三叶厚主要受基因显性效应控制,倒二叶主要受基因加性×环境互作效应控制,剑叶长、剑叶厚主要受基因显性×环境互作效应控制,倒二叶长、倒二叶面积、倒三叶长、倒三叶宽、倒三叶面积主要受基因加性×加性上位性×环境的互作效应控制.     

Test Bench of Air Braking System for Vehicles

The stability of the brake system is a key factor for the vehicle safety.It is important for the air braking system's stability to shorten the time lag between the front brake and the rear brake,the reasonable disposal of the air pipeline and the optimization of the braking system design.A test bench is developed to test the performance of the air braking system,which is mainly made of pressure sensors,signal amplifiers,data acquisition system,computer,pressing air resource and so on.Based on this test bench,the reaction time of the system while braking and abandoning brake can be measured.Using this test bench,the performances of the air braking system of a certain commercial vehicle is detected.Compared with the actual road test,it can save the cost and the time for experiment largely.     

石羊河流域沙地6种一年生植物的种子特征

对分布在石羊河流域民勤和古浪两县沙区沙地上的6种一年生植物的种子(或果实)外观形态特征、大小、千粒质量、萌发等特性进行了观察和分析研究。结果表明:沙米、沙芥、碟果虫实、雾冰藜、盐生草和小画眉草6种一年生植物的籽实体外观形态特征差异较大,在种子的大小、千粒质量、萌发率等特性上也有较大差异;6种植物种子特性表现出的共同趋势是,种子越小,千粒质量越小,种子均匀性越好,反之,则均匀性越差;常温下沙米种子的萌发率很低,沙芥、碟果虫实和小画眉草种子萌发率较低,但是雾冰藜和盐生草种子萌发率极高,一年生植物种子的萌发机制差异较大。     

Zn2+ 对海滨木槿种子萌发及根伸长抑制效应的研究

探讨Zn2+对海滨木槿种子萌发及根伸长抑制效应对在污染严重的海滨栽种海滨木槿及海滨重金属污染植物修复具有重要意义。测定了不同Zn2+浓度梯度下的海滨木槿种子发芽率、发芽势及根的伸长量和生物量变化,结果表明,较低浓度的Zn2+能够促进海滨木槿种子萌发,但是海滨木槿种子萌发对高浓度Zn2+不敏感,只有Zn2+的浓度为400 mg/g时才对种子萌发表现出抑制作用。Zn2+对海滨木槿种子发芽的抑制效应远小于对根伸长和生物量的抑制效应。随着Zn2+胁迫浓度的升高,海滨木槿根的伸长量及生物量明显降低,海滨木槿根伸长抑制率与Zn2+的浓度有极好的正相关性。     

RNA干涉技术与棉花高油育种

 棉子脂肪酸既是重要的食用油,又是重要的工业原料。但是关于棉子遗传改良的研究报道甚少。研究表明,PEPcase和ACCase的相对活性决定种子的蛋白质与油脂的含量,应用RNAi技术抑制PEPcase催化活性,可以提高脂肪酸总量。本文概述了棉花油分与RNAi技术的研究现状,并阐述了应用RNAi技术改良棉花高油分育种的技术路线。     

Automatic Fingerprint Classification by GA-Based Neural Network

Fingerprint classification can provide an important indexing mechanism in a fingerprint database. An accurate and consistent classification can greatly reduce fingerprint matching time for large database. In the paper, by combining genetic algorithm and neural network is presented a fingerprint classification algorithm which is able to achieve an accurate classification. By inputting the global feature represented by directional image to three layer neural network trained by genetic algorithm, the fingerprints were classified into six categories: whorl, right loop, left loop, arch, double loop and undiscerning type successfully.     

密度对红豆草农艺性状和种子产量的影响

为了合理利用空间资源,提高红豆草种子产量,试验以奇台红豆草为材料,设置不同的种植密度,通过对株高、分枝数、荚果数、千粒重、种子产量等指标的测量,探寻密度与红豆草生殖格局的关系。试验结果表明,种植密度30 cm×25 cm时,单株花序数、荚果数、千粒重和种子产量最高,依次是81.1个、839.2个、23.8 g、1995.8 kg/hm²。通过相关性分析,种子产量与千粒重呈显著正相关,相关系数为0.631;种子产量与单株荚果数呈极显著正相关,相关系数高达0.998。     

Numerical simulation on phasing strategy for a gasoline engine with continuously variable intake camshaft

Intake camshaft equipped with continuously adjustable cam phasing units is applied to a 486Q gasoline engine. Phasing strategies are researched through engine cycle simulation to achieve superior engine performance. The simulation results show that at high load and low and moderate speed of the engine,phasing adjustment can lead to 6% to 8% increase in power performance because phasing advance contributes to suppressing intake backflow at IVC(intake valve closed). Cam phases obtained from numerical optimization have good agreement with engine test. At moderate load,cycle simulations show that phasing advance can increase residual gas coefficient from 9% to 20%,and reduce NO emission by 80%,BSFC(brake specific fuel consumption) by 2% at a demonstration operation. With regard to fuel economy and emissions,adjustment and optimization of intake phasing at moderate load are further verified by engine test. At low load,technical approaches to enhance combustion stability,reduce HC emission and improve cold start are investigated. The effectiveness of suppressing exhaust backflow into intake duct by phasing retard is testified by simulation. Phasing changes at the operating condition are optimally obtained by engine test for improvement of combustion stability.     

甜玉米保鲜与加工技术研究进展

甜玉米作为新型果蔬食品,近年来在我国得到迅速发展。本文对甜玉米的品质特性、适宜采收期、贮藏、加工技术及应用等方面的研究现状和发展趋势进行了综述,可为甜玉米的深入研究和进一步开发利用提供参考。     

AFLP标记与棉花重要农艺性状的关联研究

 以陆地棉（Gossypium hirsutum L.）品种中棉所8号和海岛棉（Gossypium barbadense L.）品种Pima 90-53杂交产生的包含91个单株的BC₁F₂群体及其衍生BC₁F_2:3群体为材料,利用逐步多元回归分析确定分子标记与重要农艺性状的相关关系,为分子标记辅助选择提供依据。试验材料分别种植在保定市郊和沧州青县两个点,每个株行考察衣分、子指、铃重、皮棉重、子棉重5个产量性状和2.5%纤维跨距长度、马克隆值、纤维整齐度、纤维伸长率、纤维比强度5个品质性状。以20对AFLP引物组合产生的125个位点对10个重要农艺性状进行多元线性回归分析,发现其中4对引物组合产生的15个位点与10个性状有着显著相关性（P≤0.05,P≤0.01）,而后通过逐步多元回归分析获得6个位点,对9个农艺性状所解释的表型变异为6.2%～30%。结果表明,与9个农艺性状显著相关的6个AFLP位点可以用于未来的分子标记辅助育种计划。