Zinc fractions and availability to soybeans in representative soils of Northeast China

Purpose  

Limited information exists about the zinc (Zn) status of major soils in northeast China, and their ability to supply Zn to soybeans. This study aims to establish the critical concentrations of Zn in soil for plant growth, to characterize the Zn forms in soil, to correlate the concentration of various Zn forms with Zn uptake by soybeans, and to identify the most effective means of Zn application.     

利用蒸发冷却空调开展控温储粮试验

在拱板式高大平房仓的拱板间安装蒸发冷却空调开展控温储粮技术,解决拱板间的积热,以达到延缓仓内温度和上层粮温上升速度的目的。蒸发冷却空调主要利用水泵抽取水槽内的水,通过分水器均匀分布到特殊纤维制成的湿帘组件上,而大流量轴流风机的转动令仓外空气以极高速度穿过湿帘组件将湿气散发到空间,以增加空气中的湿度,通过正压促使空气流动,从而达到换气降温的效果。试验结果表明,利用低功率蒸发冷却空调,可以有效排除拱板间的积热,实现换气降温、节能、环保、绿色储粮的目的。     

Color stability, reducing activity, and cytochrome c oxidase activity of five bovine muscles

The objective was to characterize the beef psoas major (PM), longissimus lumborum (LL), superficial semimembranosus (SSM), deep semimembranosus (DSM), and semitendinosus (ST) muscles for differences in instrumental and visual color, metmyoglobin-reducing activity (MRA), total reducing activity (TRA), and cytochrome c oxidase activity. The LL and ST had the most color stability and MRA (p < 0.05), the DSM and PM had the least (p < 0.05), and values for the SSM were intermediate. Visual color (r = -0.66) and a and chroma (r = 0.68) were more correlated with MRA than with TRA (r < 0.14 for all measures). This research supports previous reports that color stability among muscles is variable and that MRA is more useful than TRA for explaining the role of reducing activity in muscle-color stability.     

Chemical kinetic behavior of chlorogenic acid in protecting erythrocyte and DNA against radical-induced oxidation

As an abundant ingredient in coffee, chlorogenic acid (CGA) is a well-known antioxidant. Although some works have dealt with its radical-scavenging property, the present work investigated the protective effects of CGA on the oxidation of DNA and on the hemolysis of human erythrocytes induced by 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH) by means of chemical kinetics. The inhibition period (t(inh)) derived from the protective effect of CGA on erythrocyte and DNA was proportional to its concentration, t(inh) = (n/R(i))[CGA], where R(i) refers to the radical-initiation rate, and n indicates the number of radical-propagation chains terminated by CGA. It was found that the n of CGA to protect erythrocytes was 0.77, lower than that of vitamin E (2.0), but higher than that of vitamin C (0.19). Furthermore, CGA facilitated a mutual protective effect with VE and VC on AAPH-induced hemolysis by increasing n of VE and VC. CGA was also found to be a membrane-stabilizer to protect erythrocytes against hemin-induced hemolysis. Moreover, the n of CGA was only 0.41 in the process of protecting DNA. This fact revealed that CGA served as an efficient antioxidant to protect erythrocytes more than to protect DNA. Finally, the reaction between CGA and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) radical cation (ABTS(+*)) or 2,2'-diphenyl-1-picrylhydrazyl (DPPH) revealed that CGA was able to trap radicals by reducing radicals more than by donating its hydrogen atoms to radicals.     

甜高粱田间去叶装置的初步试验

研制的甜高粱田间去叶装置,可安装在收割机前,利用拖拉机液压升降系统压力油为动力,通过液压马达驱动橡胶弹性剥指高速回转,剥去甜高粱叶。试验表明,采用这种弹性剥指去叶装置,可在茎秆切断前,于机械化收割同时在田间去叶,去叶率较高。液压传动型式简化了结构,解决了总体布置的难度,有利于在生产中应用。     

Mitochondrial reduction of metmyoglobin: dependence on the electron transport chain

Reduction of ferric myoglobin (metmyoglobin, MetMb) to its ferrous form is important for maintaining fresh meat color because only reduced myoglobin can bind oxygen to form the consumer-preferred cherry red color in fresh meat. The objective of this study was to characterize an apparent mitochondria electron transport chain (ETC)-linked pathway for MetMb reduction in vitro. MetMb was reduced in the presence of mitochondria and succinate (p < 0.05); mitochondria or succinate alone did not facilitate MetMb reduction relative to controls (p > 0.05). Flushing samples with oxygen greatly decreased MetMb reduction, while flushing with argon increased MetMb reduction when compared with controls (p < 0.05). ETC inhibitors were used to localize the site where electrons became available for MetMb reduction. MetMb reduction was increased by rotenone addition and decreased by malonic acid (p < 0.05); the reduction was completely abolished by additions of antimycin A or myxothiazol when compared with controls (p < 0.05). These results suggest that electrons become available for MetMb reduction at a site(s) between complex III and IV. Mitochondrial ETC-linked MetMb reduction increased with increased mitochondrial density and succinate concentration (p < 0.05); the greatest MetMb reduction was observed at pH 7.2 and 37 degrees C, and ETC-linked MetMb reducing activity decreased with time postmortem (p < 0.05). These results indicate that ETC-linked MetMb reduction exists but would be minimally active in postmortem muscles.     

1DSZ-350型悬挂式水田单侧旋耕镇压修筑埂机的设计与试验

为提高水田筑埂作业质量与效率,减轻作业劳动强度,结合东北地区水稻种植农艺要求,研究设计了1DSZ-350型悬挂式水田单侧旋耕镇压修筑埂机。阐述分析了机具整体设计方案与工作原理,对其关键部件偏牵引悬挂仿形调节系统、旋耕筑埂深度可调式传动总成、旋耕集土刀辊总成和镇压筑埂圆盘总成进行了理论分析与结构设计。为获得修筑埂机最佳工作参数组合,以机具前进速度和旋耕工作转速为试验因素,田埂平均坚实度和高度变异系数为试验指标,进行了多因素二次通用旋转组合台架试验,运用Design-Expert 6.0.10软件建立因素与指标间数学模型,采用多目标参数优化确定机具最佳作业状态。试验结果表明,当机具前进速度为1.33 km/h,旋耕工作转速为525 r/min时,筑埂作业性能最优,满足旋耕集土及镇压筑埂要求,其所筑田埂平均坚实度为2 160 k Pa,高度变异系数为4.01%。田间试验表明,该机具作业性能稳定,所筑田埂质量良好,各项指标均满足筑埂作业要求。该研究为水田机械化筑埂机具的创新研发与优化提供理论支撑和技术参考。     

聚丙烯酰胺增加土壤降雨入渗减少侵蚀的模拟试验研究Ⅱ.侵蚀

土壤侵蚀和雨水的流失是干旱、半干旱地区制约农业发展乃至生态环境良性循环的两个主要因素。聚丙烯酰胺 (PAM ,Polyacrylamide)对土壤的性质有着明显的改进作用 ,PAM具有良好的黏结力 ,能有效改良土壤的表层结构 ,提高土壤的稳定性 ,增加土壤的入渗率 ,减少土壤侵蚀。本文试图通过人工降雨模拟实验 ,获得不同的PAM的使用量及覆盖率与土壤侵蚀量在不同的雨强、不同的坡度条件下的关系。实验表明 ,经PAM处理后土壤的入渗性能和抗侵蚀的性能都有所提高 ,PAM能明显地黏结着土壤表面的颗粒 ,形成大的团聚体 ,阻碍土壤结皮的形成 ,减少土壤侵蚀。     

不同脱粒元件对切流与纵轴流水稻脱粒分离性能的影响

为研究不同脱粒元件对切流与纵轴流脱粒分离性能的影响,该文在自行研制的纵轴流脱粒分离试验台上,利用自制的矩形齿板、短纹杆-板齿、钉齿、刀形齿、梯形板齿对喂入量为7及8 kg/s的水稻进行了脱粒分离性能试验,对比切流装置在不同脱粒元件下的功耗和初脱分离率及纵轴流复脱装置在不同脱粒元件下的总功耗、夹带损失率、脱净率、破碎率、脱出混合物轴向和径向分布等指标。结果表明,在7 kg/s水稻喂入量时,刀形齿切流装置初脱分离率最高为47.71%,钉齿纵轴流复脱装置夹带损失最低为0.25%;切流装置采用刀形齿且纵轴流复脱装置采用钉齿,在8 kg/s水稻喂入量时,单位功耗最低为8.51 kW/(kg·s),夹带损失最低为0.31%,脱净率达到99.96%。