航苜1号航天二次搭载SP 1代的农艺性状变异

本研究以航天二次搭载的航苜1号紫花苜蓿(Medicago sativa cv.Hangmu No.1)种子种植而成的当代(SP_1)试验材料(HY2)为研究对象,通过与未搭载的航苜1号种植材料(CK)的农艺性状进行比较,分析了航天二次搭载对航苜1号产生的诱变效应。初步结果表明,二次搭载的航苜1号,其平均株高、分枝数和多叶率显著高于对照(P0.05),表现出较强的生长势;多叶株较对照减少,7叶株显著增多(P0.05),出现了5株7叶率在60%以上的7叶株;5叶株较对照减少,5叶率在60%以上的5叶株较对照显著增加(P0.05),诱变效应明显,有益变异增多。该研究将为苜蓿品种的进一步改良提供有效的选育途径及优良的种质资源。     

农杆菌介导的蝴蝶兰基因转化系统的建立

 针刺后的蝴蝶兰‘White Hikaru’的类原球茎(PLB)，与含绿色荧光蛋白基因( )和潮霉素磷酸转移酶基因(^p￡)的pCAMBIA 1300一SmGFP的根瘤农杆菌LBA4404 共培养，培育出了转基因的蝴蝶兰。经绿色荧光蛋白检测和Southern印迹，证实了再生植株中含cop基因和hpt基因。     

间作模式下小麦联合收获机清选装置CFD-DEM气固耦合仿真与试验验证

为了提高间作模式下小麦联合收获机清选性能,研究旋风分离筒内流场和颗粒的运动状态,探索分离筒的最佳工作参数组合,运用离散元法和计算流体力学耦合的方法分析了气流与颗粒的相互作用,以喂入速度、吸杂压强、筒体高度、下椎体角度为试验因素对清选过程进行了仿真正交试验,对最佳清选参数组合完成了田间试验验证。结果表明:气流在分离筒内形成内、外旋涡,内漩涡的运动使短茎秆进入吸杂管道,籽粒在外旋涡的作用下滑落到集粮盘;仿真试验的最佳参数组合为喂入速度12 m·s^-1吸杂压强-1 800 Pa、筒体高度350 mm、下椎体的角度65°,得到的清洁率和损失率分别为92.18%和1.99%,与田间试验的误差分别为2.947%和7.428%。     

芜菁夜蛾线虫在防治桃小食心虫上的应用

应用芜菁夜蛾线虫Ｓｔｅｉｎｅｒｎｅｍａ ｆｅｌｔｉａｅ ａｇｒｏｔｅｓ防治桃小食心虫Ｃａｒｐｏｓｉｎａ ｎｉｐｏｎｅｎｓｉｓ Ｗａｌｓｉｎｇｈａｍ的研究表明，线虫寄生桃小的温湿度范围：温度２０℃－３５℃，土壤含水量７％－１５％，以温度２５－３０℃，含水量１０％左右致死速度最快。此特性与桃小越冬幼虫出土所需求的条件相一致，肯定了应用线虫防治桃小在出土期为宜，线虫的施用量为每ｍ＾２６０－８０万头，持续     

路面条件对双桥驱动车辆寄生功率的影响

在建立不同路面条件滑转率计算模型的基础上,推导了前轮大于后轮和前轮小于后轮两种情况下双桥驱动车辆寄生功率的求解方程。以双桥驱动轮式装载机为例,定量地计算了滚动阻力系数、地面土壤状态、土壤相对含水量等地面因素对寄生功率的影响,获得了一些有益的结论。     

覆膜和露地旱作春玉米生长与蒸散动态比较

利用土壤水分传感器、微型蒸渗仪与涡度相关系统,连续监测覆膜和露地春玉米田土壤水分、蒸发和农田蒸散,分析春玉米田蒸散与土壤蒸发变化规律,探讨了覆膜玉米高产节水增效的机理。结果表明:与露地相比,覆膜的表层土壤温度和体积含水率分别提高4.9%和19.5%。覆膜、露地处理玉米出苗率分别为99.0%和80.0%,其差异为显著水平,覆膜提早春玉米各生育阶段平均为7d,全生育期缩短11d。生育前期、中期,覆膜的叶面积指数、株高和地上、地下干物质均显著高于露地的,播种一个月后差异最大,分别高110.2%、13.5%、42.9%和12.7%。玉米拔节期前(6月前)和8月后至玉米成熟,覆膜的农田蒸散量分别比露地的低6.8%和0.4%,但6-8月覆膜的比露地的高5.1%。全生育期覆膜的农田蒸散量为376.2mm,降低了6.0%,且土壤蒸发降低了57.7%。最终单株平均果穗质量、生物量差异不显著。但是,由于覆膜显著提高了出苗率从而增加了单位面积生物产量和经济产量,增幅分别为23.7%和15.3%。同时,覆膜作物水分利用效率提高了22.6%,达到31.3kg/(hm2·mm)。可见,覆膜能显著降低土壤蒸发和农田总蒸散量;保水增温促出苗,提前玉米各生育期;生育中期日蒸散量和干物质积累速率较高;最终显著提高单位面积生物产量和经济产量以及作物水分利用效率。     

制动工况下液力偶合器流场湍流模型分析与验证

合理选择湍流模型是获取准确和可靠数值模拟结果的关键。该文采用3种湍流模型(标准k-ε模型、分离涡模型、大涡模拟模型)仿真制动工况下方形腔液力偶合器流场,提取流速场和涡量场。基于粒子图像测速(particle image velocimetry,PIV)技术测量液力偶合器制动工况下流场,将数值模拟结果与PIV试验结果进行对比,以PIV试验测量结果作为评价基准,分析采用3种湍流模型计算流场结果的差异性,完成湍流模型的适用性分析。结果表明,标准k-ε模型仿真结果与PIV试验结果误差较大;采用大涡模拟模型模拟主流区域流场结构分布更加真实,仿真结果能够较好地解释主流区域多尺度涡旋运动规律和能量耗散机理;采用分离涡模型能够更准确地捕捉近壁面和角涡区高梯度流场结构分布。研究结果可为液力偶合器流场精确计算与性能预测提供参考。     

Different crop rotation systems as drivers of change in soil bacterial community structure and yield of rice, <Emphasis Type="Italic">Oryza sativa</Emphasis>

Intensive cropping, especially of rice, is considered to contribute to negative effects not only on soil chemical and biological properties but also on long-term grain yield. Appropriate crop rotation is often practiced as an alternative strategy to overcome the negative side effects of intensive cropping. Although soil microbial diversity and community structure have been shown to respond differently to altered agricultural management practices, little is known about possible links between crop rotation and grain yield on bacterial communities in rice paddy soil. In this study, we investigated the impact of specific rotational crops and compared it with intensive rice cultivation. The main crop rice (Oryza sativa) was rotated with maize (Zea mays) and mungbean (Phaseolus aureus) in different combinations in a system cultivating three crops per year. Soil bacterial communities were studied in two different cropping periods using pyrosequencing of the variable V4 region of the 16S rRNA. Our results showed that rotation with alternative crops increased rice yield by 24–46% depending on rotation structure and that bacterial community structure was altered in the presence of mungbean and/or maize compared to that in rice monoculture. In the crop rotation systems, composition, abundance, and diversity of soil bacterial communities were significantly different and higher than those in rice monoculture. Our results show that effects of crop rotation relate to changes in soil bacterial community structure suggesting that appropriate crop rotations provide a feasible practice to maintain the equilibrium in soil microbial environment for sustainable rice cultivation.     

基于RAGA-DP的饲草料作物非充分灌溉制度优化模型

中国北方牧区水资源极其匮乏,灌溉饲草料基地优化配水时,通过对非充分灌溉条件下饲草料作物进行灌溉制度优化可以有效地提高水分利用率及作物产量。该文采用基于实数编码的加速遗传算法（RAGA）与多维动态规划法（DP）相结合,建立了遗传动态规划（RAGA-DP）模型,对内蒙古锡林郭勒典型草原区灌溉饲草料地非充分灌溉条件下青贮玉米、披碱草和苜蓿进行了灌溉制度优化,试验验证结果较好,有效地解决了有限水量条件下不同生育期进行优化配水的问题,并通过相对产量与供水量、水分生产率函数和边际产量的关系得到了3种作物的适宜供水量范围。该模型解决了多维动态规划法在作物非充分灌溉条件下灌溉制度优化过程中的早熟现象及易陷入局部最优而难于求得真正最优解的问题。     

Under drought conditions NaCl improves the nutritional status of the xerophyte Zygophyllum xanthoxylum but not of the glycophyte Arabidopsis thaliana

Zygophyllum xanthoxylum is a salt‐accumulating xerophytic species with excellent adaptability to adverse environments. Previous studies demonstrated that Z. xanthoxylum absorbs a great quantity of Na⁺ as an osmoregulatory substance under arid conditions. To investigate the nutritional status of Z. xanthoxylum in comparison with a typical glycophyte, Arabidopsis thaliana, seedlings were exposed to NaCl (50 mM for Z. xanthoxylum and 5 mM for A. thaliana), osmotic stress (–0.5 MPa), and osmotic stress combined with the NaCl treatment. Compared to the control, NaCl treatment or osmotic stress significantly increased Na⁺ concentration in leaves and roots of Z. xanthoxylum, but not of A. thaliana. Under osmotic stress, the addition of NaCl significantly increased Na⁺ concentration in leaves and roots of Z. xanthoxylum, resulting in improved biomass and tissue water content. However, such changes were not observed in A. thaliana. Compared to the control, K⁺ concentrations in leaves and roots remained unchanged in Z. xanthoxylum when exposed to osmotic stress, with or without additional 50 mM NaCl. In contrast, significant reductions in shoot K⁺ concentrations of A. thaliana were observed under osmotic stress alone or when combined with 5 mM NaCl. Moreover, NaCl alone or when combined with osmotic stress enhanced the accumulation of N, P, Fe, Si, Ca²⁺, and Mg²⁺ in Z. xanthoxylum, but did not cause such nutritional changes in A. thaliana. Compared to the glycophyte A. thaliana, Z. xanthoxylum could accumulate Na⁺ and maintain the stability of nutritional status at a relatively constant level to cope with drought stress.