支持电解质浓度对磷酸根在可变电荷土壤表面吸附和解吸的影响

研究了离子强度对2种可变电荷土壤中磷酸根吸附和解吸的影响。结果表明,当pH分别大于3.7和4.0时,红壤和砖红壤对磷酸根的吸附量随离子强度的增加而增加;当pH分别小于3.7和4.0时,红壤和砖红壤对磷酸根的吸附量随离子强度呈相反的变化趋势。电解质主要通过改变离子专性吸附面上的电位来影响磷酸根的吸附。Zeta电位的测定结果表明,当pH大于土壤胶体的等电点(IEP)时,吸附面上电位为负值,且随离子强度增加数值减小,对磷酸根的排斥力减小,土壤表面对磷酸根的吸附量增加;当pH小于IEP时,吸附面上的电位为正值,它随离子强度增加而减小,不利于磷酸根的吸附。解吸实验的结果表明,吸附于可变电荷土壤表面的磷酸根在去离子水中的解吸量高于0.1 mol L-1NaNO3体系中的解吸量。这同样由于电解质浓度对土壤表面吸附面上的电位的影响所致。     

Alternating one lung ventilation using a double lumen endobronchial tube and providing CPAP to the non-ventilated lung in a dog

Introduction This case report describes the anaesthetic management of exploratory thoracoscopy and alternating one lung ventilation (OLV) in a dog with a pulmonary bulla, and the application of continuous positive airway pressure (CPAP) to the non‐ventilated lung for preventing and treating hypoxia. Case history A 6‐year‐old, male castrated Border collie was scheduled for exploratory thoracoscopy to investigate spontaneous pnemothorax that had not resolved with repeated suction. Specific requirements for the thoracoscopy were alternating OLV to allow the surgical access to the right middle lobe and its removal, and the examination of the left hemithorax to rule out the presence of other lesions. Diagnosis and management Selective lung ventilation was performed with a double lumen endobronchial tube (DLT), inserted under endoscopic guidance. After a short period of two lung ventilation during preparation of the surgical field, alternating OLV was performed, combining CPAP, provided to the non‐ventilated lung via a Mapleson D breathing system, and positive end‐expiratory pressure (PEEP) applied to the ventilated lung. Left OLV occurred first and resection of the right middle pulmonary lobe was successfully performed; right OLV followed to allow the examination of the left hemithorax. Discussion and conclusions The combination of CPAP and PEEP resulted in a satisfactory intra‐operative management of hypoxemia. Alternating OLV can be performed successfully by using a DLT. CPAP, commonly employed in human medicine, should be considered an important tool in the anaesthetic management of OLV in small animals.     

双层和夹层包膜工艺对水基树脂包膜材料控释性能的影响

为了优化水基树脂的包膜控释性能,该文以脂溶性树脂为配合包膜材料,利用底喷风动流化床制造多层包膜控释尿素,并通过包膜控释尿素养分释放率的测定评价双层和夹层包膜工艺对水基树脂包膜材料控释性能的影响.研究结果表明:两种工艺相比,夹层包膜工艺能显著延长包膜控释尿素的肥效期,其肥效期是双层包膜工艺的5倍.在夹层包膜工艺中,内保护层厚度在5～15 g/m2的范围内对包膜控释尿素的肥效期无明显影响,50 g/m2水基树脂控释层和10g/m2脂溶性树脂外保护层夹层控释尿素的肥效期均约为260 d.但是,夹层包膜控释尿素的养分释放模式与内保护层厚度有关,内保护层厚度达到10 g/m2以上时,养分释放模式由抛物线型变成了S型.综上可知,脂溶性树脂内保护层较适宜的厚度为5～10 g/m2,采用夹层包膜工艺能更好的发挥水基树脂的控释性能.     

黑麦草鲜草翻压还田对双季稻CH4与N2O排放的影响

为了研究黑麦草鲜草翻压还田对稻田温室气体排放的影响,该文利用静态箱-盆栽装置观测了尿素、黑麦草鲜草翻压还田、半量尿素与半量黑麦草鲜草混施和对照4个处理稻田CH4和N2O排放.结果表明:黑麦草鲜草翻压还田、半量尿素与半量黑麦草鲜草混施的CH4排放通量分别比对照增加了371％和210％,比尿素增加了152％和66％:尿素的CH4排放比对照高87％,差异均达到显著水平(P＜0.05).黑麦草鲜草翻压还田的CH4排放在3个时期(早稻移栽前,早稻生长期和晚稻生长期)分布均匀,约60％的CH4排放于早稻移栽前和早稻生长期.尿素的N2O排放分别为黑麦草鲜草翻压还田、半量尿素与半量黑麦草鲜草混施和对照的18倍、6.6倍和25倍.CH4和N2O的全球增温潜势(GWP)依次为黑麦草鲜草翻压还田＞半量尿素与半量黑麦草鲜草混施＞尿素＞对照,差异均显著(P＜0.05).黑麦草鲜草翻压还田虽然增加了稻田CH4排放,但减少了N2O排放,抑制了 尿素对N2O的排放.     

中国石蒜生长特性及高量施肥研究

研究了高用量的尿素和氮磷钾(N-P-K)复合肥双因素施肥对中国石蒜(Lycorischinensis)的当季和次年叶生长量及鳞茎生物量的影响,并且对叶量进行了主观评价。结果表明:高用量的尿素对中国石蒜的生长产生负面影响;N-P-K复合肥对中国石蒜生长未达到显著性影响水平;叶的数量与鳞茎生物量呈线性正相关;主观评价定性结果与鳞茎生物量结果类似。     

多菌灵草酸盐双向传导本质原因的初步探讨

采用紫外光谱法测定了多菌灵草酸盐和多菌灵分别处理棉苗后，对棉叶的穿透速率和棉苗内的定量分布，以及这两种农药的油水分配系数，并用重量法测定了棉叶、棉根、茎韧皮部和木质部等生物样品的油水分配系数，结果表明：多菌灵草酸盐在棉苗内具有双向传导作用，初步探明向传导的本质原因是由于草酸羧基的引入，使其具有与棉苗各部位的油水分配系数更加接近的油水分配系数，根据相近相通原理，因而更容易穿透棉苗各部位，并进行双向传导。     

双道原子荧光光谱法同时测定蔬菜中的砷和汞

采用湿法消解样品 ,应用双道原子荧光光谱法同时测定蔬菜中的砷和汞 ,探讨了酸度、硼氢化钾质量分数、载气流量、灯电流强度以及原子化器高度等因素对测定的影响 .在最佳试验条件下 ,砷、汞的检出限分别为 0 10 8μg/L、0 0 0 9μg/L ,回收率砷为 98%、汞为 90 % ,相对标准偏差砷为 0 83%～ 1 5 2 % ,汞为 0 6 9%～ 1 4 1% .     

京郊地区小麦、玉米两茬间氮、磷、钾肥的合理施用

在京郊不同土壤肥力条件下,进行小麦、玉米两茬间氮、磷、钾肥合理施用的研究.三年多点试验结果表明,全年氮素投入0.036～0.048kg/m~2,以小麦、玉米各半或玉米居多为宜.冬小麦施氮在下茬玉米上无明显后效.冬小麦适宜施氮量为0.024kg/m~2,夏玉米适宜施氮量0.030kg/m~2,冬小麦和夏玉米施磷肥不仅对当季有增产作用,而且对下茬作物也有明显的后效.冬小麦施P_2O_5 0.015kg/m~2、夏玉米0.007kg/m~2为宜.夏玉米比冬小麦对钾肥高度敏感,土壤速效钾含量在90×10~6以下,冬小麦施钾有一定增产效果,而夏玉米施钾肥显著增产.     

QTL analysis of seed storability in rice

A double haploid population, which consists of 127 lines derived from anther culture of a typical indica and japonica hybrid ‘ZYQ8’/‘JX17’, was used in this study. Seed storability was investigated by using the storage property measured by the difference of seed germination rates before and after treatment of the rice seeds under 40°C and 95% relative humidity for 10 days in a phytotron. Three QTLs related to rice seed storability were detected on chromosomes 9, 11 and 12, with the LOD scores 2.76, 4.83 and 2.54, respectively, together explaining 35.4% of the genetic variation. The ‘JX17’ allele at qLS‐9 and the ‘ZYQ8’ alleles at qLS‐11 and qLS‐12 could enhance the rice seed storability. The effects of the ‘ZYQ8’ alleles of qLS‐11 and qLS‐12 were also verified using chromosome segment substitution lines.     

Effects of γ-radiation on vitality and competitive ability of Cucumis pollen

Summary Pollen of 4 Cucumis sativus genotypes and of the related species C. metuliferus and C. zeyheri 2x was irradiated with four doses of -rays: 1, 2, 4 and 5 kGy. Higher radiation doses were found to inhibit germination and pollen tube growth in vitro with C. sativus, the most sensitive species.Irradiated pollen of cucumber never performed normal fertilization. However, after radiation with 1 kGy, cucumber pollen was able to occupy all available ovules, of which about 50% developed into empty seeds without embryo. This makes 1 kGy-irradiated maternal pollen less suitable to serve as mentor pollen in interspecific hybridizations. Doses of 2 kGy and more appeared to eliminate the ability to compete for ovules, while fruit set after a 2 kGy radiation was still high.