Impact of soil water content on maize responses to the plant growth-promoting rhizobacterium Azospirillum lipoferum CRT1     

Sonia Czarnes  Pierre-Edouard Mercier  Damien G. Lemoine  Jihane Hamzaoui  Laurent Legendre 《Journal of Agronomy and Crop Science》2020,206(5):505-516

Members of the bacterial genus Azospirillum are root-associated bacteria that increase yield in cereals by promoting growth and alleviating drought stress. How plants integrate the many bacterium-derived growth-promoting stimuli with other environmental factors to generate a coordinated response remains unresolved. Using a commercial Azospirillum strain, A. lipoferum CRT1 and two host maize cultivars, it was observed that bacterization reduced the drought-induced increase in lateral root growth and enhanced the flood-induced increase in lateral root growth in the more drought- and flood-sensitive cultivar. In the other one, A. lipoferum CRT1 only elicited a moderate root growth response under low soil water potential. The photosynthetic potential and activity were increased in the earlier cultivar and decreased in the later one, irrespective of the soil water content. No impact of the bacterium was seen on the growth of the leaves of both cultivars under both stresses until the third leaf stage, therefore suggesting that it is a consequence of multiple primary adaptations to biotic and abiotic stresses. It is suggested that host–bacteria recognition leads to a stress-specific modulation of the root response and a differential stress-independent effect on photosynthesis. This is the first report of the impact of Azospirillum under flood conditions.  相似文献   

基于单片机的脉码传输仪设计     

蔡昌新  李国芳 《长江大学学报》2006,(4)

以单片机为核心,采用软件、硬件相结合的方法,充分利用单片机的硬件中断资源,实时响应地面的声波逻辑脉冲,分离其接收和发射逻辑。同时该仪器以地面声波逻辑为工作时序,分时采集模拟道数据、脉冲道数据及向地面传输PCM数据。该脉码传输仪既能完成PCM3506的全部功能,又能监测仪器工作环境的温度及测井套管接箍的压力。  相似文献   

湖北省分地区水灾损失等级划分初探     

刘新卫 《湖北农学院学报》2003,23(4):251-253,257

建立了湖北省分地区水灾损失灾度等级的划分标准。基于模糊模式识别理论，按最大隶属原则和择近原则对灾度等级进行了模糊综合评判。  相似文献   

发展我国洪水保险的制度思考——美国洪水保险制度的借鉴与启示     

鲜明 《四川畜牧兽医学院学报》2005,3(3):33-35

洪水保险是一项重要的非工程防洪措施.美国是世界上最早建立国家强制性洪水保险体制的国家,经过艰难曲折的探索,闯出了一条成功之路.我国的洪水保险体制还处于积极探索阶段.中美两国尽管国情差异较大,但以洪水保险作为推进洪泛区洪水风险管理的经济手段,并以立法和国家计划等措施来保障实施的作法是值得借鉴的.本文就美国洪水保险制度的发展与沿革,寻找对我国建立洪水保险制度一些有益的启示,并就此提出了一些建设性意见.  相似文献   

基于伺服控制系统的MJK6227型往复式裁板锯     

刘青科  杨佳  周玉庭 《林业机械与木工设备》2006,34(5):42-44

通过伺服控制系统在MJK6227型往复式裁板锯上的应用,可以看出与传统的电控系统相比,该机具有较高的灵活性和准确性。便于用户实现较高的工作精度和较为快捷的工作要求。试验表明,系统能够满足该机的各种动作要求,且在工作过程中可以反馈锯片的即时动作。目前,该系统已在铣床、砂光机等数控机床控制系统设计中推广应用。  相似文献   

加热光纤法同步测定土壤水热参数误差分析     

胡优  司炳成  李敏  何海龙  何冬  任姮烨  刘吕刚 《土壤学报》2024,61(4)

土壤水热参数是研究土壤水热传输的基本物理参数。当前热脉冲探针法（HPP）可同步测定土壤水热参数,但该方法仅限于在点尺度下测定。与其具有相同理论基础的加热光纤法（SPHP-DTS）,可将测定尺度增大至田间千米尺度,但其测定精度尚未得到有效验证。为了探知SPHP-DTS法的误差,本研究进行了SPHP-DTS法与HPP法测定土壤水热参数的对比试验。结果表明,以HPP为标准,加热光纤法测定热导率的精度RMSE为0.13 W?m-1?℃-1。SPHP-DTS法测定的热导率显著高于HPP法,主要原因在于加热光纤时产生的温度效应。通过热导率法测定土壤含水率时,在热导率测定误差的影响下,SPHP-DTS法的测定精度明显低于HPP法。SPHP-DTS法测定土壤水热参数的其他误差来源包括光纤与土壤之间多个界面的接触热阻、光纤的温度敏感性、噪音干扰以及温度梯度驱动下的水分迁移。本研究可为SPHP-DTS法提升土壤水热参数测定精度提供理论参考。  相似文献   

支管射流三通结构优化与试验     

薛子龙  王新坤  樊二东  徐胜荣  王轩  张晨曦 《排灌机械工程学报》2020,38(7):751-756

为了提高支管射流三通水力性能,改善滴灌的灌水均匀性,基于CFX数值模拟技术,对进口宽度为15 mm的支管射流三通进行结构优化.选取位差、劈距、劈尖半径和侧壁倾角为影响因素,通过四因素三水平正交设计了9组模型,边界条件设定为进口压力100 kPa.选取支管射流三通出口设计流量为评价标准,支管射流三通最优结构尺寸为位差5.5 mm、劈距113 mm、劈尖半径13 mm、侧壁倾角10°.此结构尺寸参数下的支管射流三通水力性能试验结果表明:在进口水压为100 kPa时,支管射流三通脉冲频率为148次/min,水头压力振幅为37.9 kPa,水头压力损失为16.7 kPa,出口流量为0.698 L/s;支管射流三通所接滴灌带长度为60 m时,与普通支管三通相比,支管射流三通的灌水均匀系数提高了2.78%,流量偏差率降低了4.72%.该研究可为射流技术在脉冲滴灌系统的研究、开发与应用提供理论依据.  相似文献   

Assessment of pulse co-oximetry technology after in vivo adjustment in anaesthetized dogs     

Hamaseh Tayari  Derek Flaherty  Tyfane T. Yamaoka  Adam Auckburally 《Veterinary anaesthesia and analgesia》2021,48(3):297-304

ObjectiveTo compare values of haemoglobin concentration (SpHb), arterial haemoglobin saturation (SpO₂) and calculated arterial oxygen content (SpOC), measured noninvasively with a pulse co-oximeter before and after in vivo adjustment (via calibration of the device using a measured haemoglobin concentration) with those measured invasively using a spectrophotometric-based blood gas analyser in anaesthetized dogs.Study designProspective observational clinical study.AnimalsA group of 39 adult dogs.MethodsIn all dogs after standard instrumentation, the dorsal metatarsal artery was catheterised for blood sampling, and a pulse co-oximeter probe was applied to the tongue for noninvasive measurements. Paired data for SpHb, SpO₂ and SpOC from the pulse co-oximeter and haemoglobin arterial oxygen saturation (SaO₂) and arterial oxygen content (CaO₂) from the blood gas analyser were obtained before and after in vivo adjustment. Bland–Altman analysis for repeated measurements was used to evaluate the bias, precision and agreement between the pulse co-oximeter and the blood gas analyser. Data are presented as mean differences and 95% limits of agreement (LoA).ResultsA total of 39 data pairs were obtained before in vivo adjustment. The mean invasively measured haemoglobin–SpHb difference was –2.7 g dL^?1 with LoA of –4.9 to –0.5 g dL^?1. After in vivo adjustment, 104 data pairs were obtained. The mean invasively measured haemoglobin–SpHb difference was –0.2 g dL^?1 with LoA of –1.1 to 0.6 g dL^?1. The mean SaO₂–SpO₂ difference was 0.86% with LoA of –0.8% to 2.5% and that between CaO₂–SpOC was 0.66 mL dL^–1 with LoA of –2.59 to 3.91 mL dL^–1.ConclusionsBefore in vivo adjustment, pulse co-oximeter derived values overestimated the spectrophotometric-based blood gas analyser haemoglobin and CaO₂ values. After in vivo adjustment, the accuracy, precision and LoA markedly improved. Therefore, in vivo adjustment is recommended when using this device to monitor SpHb in anaesthetised dogs.  相似文献   

微分响应在降雨误差修正中的应用     

杨姗姗  包为民  杨小强  阙家骏  束慧连  李佳佳 《中国农村水利水电》2015,(1)

误差修正是实时洪水预报研究和应用中的重要内容,从修正模型降雨输入角度出发,提出了一种基于微分响应的降雨误差修正方法,并通过实例论证了该方法修正降雨量的适用性。该方法通过计算降雨所对应模型的微分响应来修正降雨,从而修正出口断面流量过程。将该修正方法结合新安江模型,对闽江建阳流域的19场历史洪水进行了有效性检验,结果表明:此方法对洪量、洪峰的修正效果明显,且能够显著提高洪水预报的合格率,修正后合格率由63.2%提高到94.7%。  相似文献   

沮漳河下游洪水遭遇地区组成规律     

蔡振华  王祥三  李娜 《中国农村水利水电》2005,(4):23-26

漳河水库由观音寺和鸡公尖两个水库以明槽渠道组成，涉及入库洪水的两个来源，而为下游防洪又涉及到与水库坝址至两河口区间及沮河洪水的组成遭遇。沮漳河为长江的一级支流，对长江防洪安全有一定的影响作用，为了确保水库及其下游防护区的安全，必须研究洪水的地区组成，为防洪错峰及安全调度提供设计依据。通过F检验法及t检验法来进行回归方程及相关系数的检验，证明回归方程是显著的，相关也较密切，可用于生产实际。  相似文献