水稻超高产育种研究进展

超高产水稻育种是当前稻作科学中的一个热点研究领域。本文综述报道开展水稻超高产育种的由来,超高产水稻的概念,国内外水稻超高产育种的现状以及水稻超高产育种突破途径等。并就水稻超高产育种与米质、抗性和地域性等问题作了讨论,还提出了水稻超高产育种中对杂交后代群体选择的一些注意要点。     

宇宙线散落核素7Be在山区表土层中的分布特征及侵蚀示踪原理

宇宙线散落核素⁷Be具稳定的物质来源和53.3天的半衰期,提供了示踪环境微粒季节性迁移的必要条件;其在土粒中主要存在于Fe-Mn氧化物及有机质结合相,适应于季节性微粒迁移示踪;它在表土层中的垂直分布特征提供了示踪微粒季节性迁移的充分条件。⁷Be在表土层中的累计值、表观比活度、最大渗透深度及相对侵蚀(或堆积)速率是土粒迁移的示踪参数。     

江西省县域农业碳排放时空格局及影响因素分析

农业生产是碳排放的主要来源之一,在碳达峰碳中和的时代背景下,厘清区域农业碳排放现状并分析其时空变化和影响因素具有重要意义。江西省是农业大省,近几十年来农业的快速发展伴随着农业碳排放量的升高。因此基于本区域水稻种植、农资投入、土壤利用及畜禽养殖4类主要碳源,构建农业碳排放测算体系,评估2000－2020年农业碳排放量,分析县域农业碳排放空间格局及其驱动机制。结果表明：1）江西省农业碳排放量总量范围在1 098.32万～1 471.94万t;种植业碳排放强度整体呈下降趋势,范围在2.50～3.87 t/万元,畜牧业碳排放强度整体亦呈下降趋势,范围在0.76～2.03 t/万元;各碳源碳排放总量和其占农业碳排放总量的比例大小依次为：水稻种植（806.72万t,61.15%）、畜禽养殖（243.57万t,18.57%）、农资投入（237.39万t,18.02%）、农田土壤利用（29.60万t,2.26%）;2）江西省县域农业碳排放量空间特征明显,高碳排放区均集中于鄱阳湖平原地区以及吉泰盆地;农业碳排放强度空间分布由相对离散到集中在赣北地区;整体上江西省碳排放总量的重心向北移动;3）农业碳排放效率是影响农业碳排放的最重要的因素,各因素对农业碳排放减少量和其占总农业碳排放减少量的比例大小依次为：农业生产效率因素（1 828.13万t,56.57%）、地区产业结构因素（1 265.29万t,39.15%）、农业产业结构因素（86.12万t,2.66%）、农村总人口因素（52.12万t,1.62%）。整体上,各因素减少农业碳排放总量绝对值由大到小为：赣北、赣中、赣南。研究结果可为江西省乃至全国其他粮食主产区农业碳排放的测算以及农业碳减排政策的制定提供科学参考。     

麦灰和砻糠用量与用法对雷竹林地土壤温度及笋产量的影响

雷竹(Phyllostachys violascens)是一种优良的笋用竹种,覆盖栽培能够促进雷竹经济效益的显著提升。试验研究了新型覆盖材料麦灰和砻糠的覆盖厚度和施用方法对雷竹林地温及笋产量的影响。结果表明:覆盖材料的覆盖厚度以23.0~23.5 cm为宜,即下层施用2.5~3.0 cm的麦灰作为增温层,上层以20.0~21.0 cm的砻糠作为保温层,竹林土壤可保持较高的温度,竹笋产量较高;在覆盖材料的施用方法上,以麦灰2次施入为好,第2次施入麦灰后覆盖上砻糠,可延长出笋期,而且有利于地表温度的平稳变化和提高雷竹笋产量。     

抗Asia1型口蹄疫病毒单克隆抗体的制备及生物学特性鉴定

用纯化的Asia1型口蹄疫病毒免疫BALB/c小鼠,取免疫小鼠脾细胞与SP2/0骨髓瘤细胞进行融合,经间接ELISA和间接免疫荧光(IFA)筛选,有限稀释法克隆,获得了2株稳定分泌单克隆抗体的杂交瘤细胞株,分别命名为3H6、5G3,其细胞培养上清效价分别为1:64和1:128,小鼠腹水效价分别为1×10~(-4)和8×10~(-3);ELISA和IFA结果显示,2株单抗仅与Asial型口蹄疫病毒反应,不与O型口蹄疫病毒反应,表明它们均为抗Asial型口蹄疫病毒的型特异性单克隆抗体。westem blot结果显示,2株单克隆抗体均不与全病毒抗原反应,表明它们所针对的抗原表位均为构象表位。相加ELISA试验表明,两株单抗识别不同的抗原表位。经硫氰酸盐洗脱法测定,3H6和5G3的相对亲和力指数分别为1.0 mol/L和1.5 mol/L。这2株单抗的获得为建立口蹄疫病毒检测方法提供了强有力的工具。     

4个野生猕猴桃优良单株果实矿质元素含量分析

为挖掘云南省猕猴桃种质资源,对滇东及滇东北部分地区的野生猕猴桃资源进行了调查收集,在对资源果实进行感官评价、形态测定分析及总糖、总酸等鉴定分析基础上,筛选出4个优良单株,对优良单株开展了矿质元素含量比较分析.结果表明,优良单株DSG-2果实的磷、锌、铁、镁、钙、铜和钠含量均最高;XSD-1果实的磷、镁、钙、铜、钠和钾含...     

Hypoxaemia during anaesthesia in seven horses with colic

Anaesthetic records of horses with colic anaesthetised between June 1987 and May 1989 were reviewed. pH and blood gas analyses were performed during 157 operations from which the horses were allowed to recover. A PaO₂ of 8.0 kPa or less was measured during anaesthesia in seven of these horses. The horses were of different breeds, ages and sexes. Anaesthesia was induced with xylazine, guaifenesin and ketamine in four horses and with xylazine, guaifenesin and thiobarbiturate in three horses. Anaesthesia was maintained with inhalation anaesthetic agent and oxygen: isoflurane in five horses, halothane in one horse, and initially halothane but later isoflurane in one horse. Systolic arterial pressures during anaesthesia ranged from 80 to 150 mmHg, diastolic arterial pressures were between 60 and 128 mmHg, and heart rates were between 28 and 44 beats /min. Controlled ventilation was initiated at the start of anaesthesia. PaCO₂ exceeded 6.7 kPa in three horses but was subsequently decreased by adjustment of the ventilator. PaO₂ of 8.0 kPa or less was measured during early anaesthesia, with one exception, and persisted for the duration of anaesthesia. The horses' inspired air was supplemented with oxygen during recovery from anaesthesia, at which time measurement of blood gases in three horses revealed no increase in PaO₂. Recovery from anaesthesia was uneventful. The surgical problems involved primarily the large intestine in five horses and the small intestine in two horses. Six horses were discharged from the hospital alive; one horse was reanaesthetised later the same day and destroyed without regaining consciousness. We concluded that none of the objective values recorded during the pre-anaesthetic evaluation could have been used to predict the complication of intraoperative hypoxaemia. We observed that once hypoxaemia developed it persisted for the duration of anaesthesia and even into the recovery period when the horses were in lateral recumbency and regaining consciousness. We assume that the altered metabolism from anaesthetic agents and hypothermia combined with adequate peripheral perfusion contributed to the lack of adverse consequences in six of the horses. The contribution of hypoxaemia to the deteriorating condition of the seventh horse is speculative.