低温胁迫下草坪草抗寒性的研究进展

通过介绍低温对草坪草的影响和作用机理,系统地综述了在低温胁迫下草坪草的光合特性、水分生理代谢、细胞质膜相对透性、保护酶系变化、碳水化合物贮藏、可溶性蛋白质含量、以及脂肪酸的变化在低温胁迫方面的研究进展,提出了今后进行草坪草抗寒性研究的趋势和建议。     

穗状玉米测产系统设计与试验

设计了由产量监视器、速度传感器、产量传感器、差分全球定位系统(DGPS)、割台高度传感器、升运器转速传感器和玉米果穗导向装置组成的穗状玉米测产系统,并应用该系统进行田间测产试验。收获作业前抽样测量玉米果穗的粒穗比和含水率;玉米收获机工作时,以割台高度传感器作为逻辑开关,割台收获玉米果穗,通过导向装置使玉米果穗以相同速度冲击产量传感器;产量传感器将冲量转化为电信号,并传给产量监视器;产量监视器融合产量、速度、升运器转速及DGPS信息计算出当前小区产量并存储在扩展名为.vld的文件中,应用自行研制的农业空间信息采集与应用系统(DCAS)可绘制收获产量图。2009年秋季应用该系统进行田间玉米收获实时测产,田间试验数据表明该系统测产平均相对误差为18.11%。     

3ZS-150型水稻中耕除草机设计与试验

设计了3ZS-150型水稻中耕除草机。对除草部件结构参数进行理论分析,据此设计了苗间和行间除草部件。该机由插秧机底盘提供配套动力,设有软轴驱动式苗间弹齿式除草盘和旋转式行间耕耘锄,可一次完成苗间和行间除草作业。田间试验表明,当中耕深度31mm、苗间除草盘转速186～190r/min、机器前进速度为0.35m/s时,除草率为80046%,伤秧率为4.76%。     

4UX—550型马铃薯收获机悬挂机组机液耦合仿真

应用Pro/E软件建立了4UX-550型马铃薯收获机与东方红200P型拖拉机悬挂机构参数化模型,进行了拖拉机悬挂机构与马铃薯收获机装配.将装配模型导入ADAMS中,建立了液压提升回路系统模型,进行了机械系统与液压系统的耦合仿真.结果表明,液压力驱动悬挂机组提升工况下,上悬挂点垂直方向出现最大力的时间要比机械力驱动滞后0.080 s,下悬挂点滞后0.088 s;下降工况下,上悬挂点滞后0.056 s,下悬挂点滞后0.060 s.液压力驱动与机械力驱动上、下悬挂点的受力基本相同,液压缸缓冲力的波动范围为5.09 ～ 15.39 N.     

Symbiotic N<Subscript>2</Subscript> fixation and nitrate utilisation in irrigated lucerne (<Emphasis Type="Italic">Medicago sativa</Emphasis>) systems

Symbiotic N₂ fixation by lucerne (Medicago sativa) has capacity to provide significant inputs of N to agro-ecosystems, and the species has also been shown to scavenge soil mineral N and thus act as a sink for excess reactive N. The balance between these two N cycle processes was investigated in an extensive irrigated lucerne growing region where nitrate contamination of groundwater has been reported. We sampled 18 permanent pure lucerne stands under irrigation for standing dry matter, total shoot N, and N₂ fixation using ¹⁵N natural abundance along with activity of the inducible enzyme nitrate reductase as indicators of use of soil NO₃⁻ by lucerne. On average 65% of lucerne N was obtained from symbiotic N₂ fixation. Converting standing dry matter estimates to annual N₂ fixation amounts we calculated average N₂ fixation of 311 kg N/ha, including N in roots and nodules. Uptake of N from soil by lucerne was calculated to be 181 kg N/ha/year. We were not able to identify the source of this soil mineral N, although nitrate reductase activity of lucerne was higher than that of non-N₂ fixing species examined.     

<Emphasis Type="Italic">Pinus halepensis</Emphasis> somatic embryogenesis is affected by the physical and chemical conditions at the initial stages of the process

Pinus halepensis has been described as a drought-tolerant species with high plasticity to growth in different environments. Its eco-physiological characteristics could facilitate the use of this species in large afforestations in the future scenery of climate change. Somatic embryogenesis is a biotechnological tool with potential for large-scale clonal propagation. In order to establish an improved regeneration protocol for Pinus halepensis, the effects of different temperatures (18, 23, and 28 °C) and water availability conditions (2, 3, and 4 g L^?1 Gelrite^®), during initiation of embryonal masses on the rate of initiation, proliferation, maturation, and the number of embryos developed, were evaluated. It was found that environmental conditions during the initiation stage of Pinus halepensis somatic embryogenesis influence the success of initiation and proliferation. In contrast, there was no effect of these conditions on the maturation rates and the number of somatic embryos. Somatic embryos were obtained in all treatments tested, indicating that plants can be produced from extreme conditions of induction, such as high temperatures (28 °C) and low water availability conditions (4 g L^?1).     

新疆多浪羊FecB突变检测及与产羔数的关系

骨形态发生蛋白受体IB基因(BMPR-IB)FecB突变是影响布鲁拉美利奴和小尾寒羊高繁殖力的主效基因.本研究采集产双羔及以上的多浪羊(Ovis aries)母羊135只及后代羔羊血样共353份,公羊血样211份,利用PCR-RFLP技术检测FecB突变,并分析不同基因型个体母羊的产羔数.结果表明:在多浪羊群体中检测到BB、B+和++基因型,基因型频率分别为0.005,0.146和0.849.B+型多浪羊产羔数均值比++型多0.51只(P<0.01),BB型多浪羊产羔数分别与B+和++型差异不显著.多浪羊群体在FecB位点上处于Hard-Weinberg平衡状态,表明在该位点上没有受到选择的影响.本研究首次在新疆多浪羊群体中发现了FecB突变BB基因型公、母羊个体(1只公羊和2只母羊),揭示多浪羊多羔产生的机理可能与布鲁拉美利奴和小尾寒羊相同,在生产过程中可以根据携带FecB突变的情况开展选种选配,组建多浪羊肉用高繁品系.