2种植物生长调节剂对四季玫瑰嫩枝生根作用的研究

在四季玫瑰嫩枝扦插育苗试验中,用ABT1^#生根粉和吲哚丁酸(IBA)不同浓度溶液处理。结果表明：植物生长调节剂ABT11^#和IBA对四季玫瑰扦插生根都有很大的促进作用,生根率比对照可提高20％～60％,在设计的几种处理中生根率效果最好的为IBA200mg／L、300mg／L、100mg／L,生根率分别为91．0％、90％、88．2％;其次为ABT11^#生根粉200mg／L,生根率为88．3％。植物生长调节剂不同浓度处理对插穗生根的质量均有显著的影响。     

THE CORRELATION OF CANINE PATELLAR LUXATION AND THE ANTEVERSION ANGLE AS MEASURED USING MAGNETIC RESONANCE IMAGES

Measurements from magnetic resonance (MR) images can be used to examine the anteversion angle (AT-angle) and its influence on the lateromedial or mediolateral luxating forces on the patella. The AT-angle of the femoral neck was measured with the aid of MR imaging in 45 pelvic limbs without patellar instability, in 33 limbs with patellar luxation and in 6 limbs with rupture of the cranial cruciate ligament. The limbs with medial patellar luxation were divided into three groups based on clinical examination. The mean (range) AT-angle was 7.6 degrees (0 degrees to 24 degrees) in the "normal" group, 8.6 degrees (-10 degrees to 29 degrees) in the group "grade II," and -0.4 degrees in the group "grade III" (-28 degrees to 12 degrees). A mean (range) AT-angle of 4.8 (-4 degrees to 11 degrees) was measured in the pelvic limbs with rupture of the cranial cruciate ligament. Compared to literature that described AT-angles based on radiographs of normal limbs, reduced AT-angles were found in this study due to different lines of measurement of the femoral neck. This study documents that the AT-angle of the femoral neck does not influence patellar instability. This study also demonstrates that MR images can be used to make exact measurements of the canine AT-angle that represent the true anatomy of the femoral neck.     

荷斯坦牛生产体内性控胚胎的试验研究

本研究采用荷斯坦牛X-性控冻精和超数排卵技术生产奶牛体内性控胚胎。结果显示,使用阴道栓(Cue-Mate)对31头供体奶牛进行同期发情处理,发情率为100%,且发情时间较集中。31头供体奶牛共回收胚胎321枚,头均回收胚胎10.35枚,其中可用胚胎225枚,头均可用胚胎7.26枚。选择36头黄牛受体进行单胚移植,其中21头移植鲜胚,妊娠10头,妊娠率47.62%;15头移植冻胚,妊娠6头,妊娠率40.00%。     

根施水杨酸对铅胁迫下小麦根系生长发育的影响

以小麦品种“轮选988”为材料,采用溶液培养法,研究了80 mg·L^-1水杨酸（SA）对铅（50 mg·L^-1 Pb²⁺）胁迫下小麦幼苗生长及生理特性的影响。结果表明:根施SA后,铅胁迫下的小麦幼苗株高、根长、株鲜重、根鲜重、株干重和根干重较对照(铅胁迫下未根施SA)分别上升了17.67%、24.85%、23.46%、18.69%、18.95%和25.41%,根系超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）活性分别上升了215.73%、98.92%、137.45%和111.47%,根中超氧阴离子（O^—[KG-1][JX*3]·[JX-*3]₂）和过氧化氢（H₂O₂）含量分别降低了23.82%和28.99%;同时,根施SA,铅胁迫下小麦根系中可溶性糖含量上升了13.59％,而Pro含量下降了40.11%,根系中丙二醛（MDA）含量降低了16.78％,小麦根系活力增加了694.52%。因此,根施SA在一定程度上提高了小麦根系的抗氧化能力,缓解了铅离子对小麦根系的毒害。     

Evaluation of an Autotutorial-Simulator Program for Instruction of Hollow Organ Closure

Forty students were randomly assigned into two study groups (traditional, T; and simulator, S) of 20 students each for a core operative practice laboratory. Students were randomly paired and their group assignment and identity remained anonymous to the evaluators throughout the study. Questionnaires were distributed to students to evaluate prior surgical experience and obtain learning resource use information. Before the evaluation sessions, both groups were given identical learning resource opportunities except students in Group S received hollow organ simulators and practice materials for gastrotomy closure. All students were forewarned that surgical instruction would not be available during the evaluation sessions. In the first live animal evaluation session, all student pairs were videotaped after which stomachs were harvested for gross evaluation of the surgical site. Group T performed an additional gastrotomy for video and gross evaluation 2 weeks later. Questionnaire, and gross and video evaluation results were compared statistically between groups and sessions. The hollow organ model did not suitably simulate live stomach tissue; the material was more fragile and stiff and suture cut-out was a problem even with appropriate suture tension and technique. The model was effective for teaching needle placement, instrument usage, creating proper tissue inversion, and methods to minimize instrument handling of tissue during gastrotomy closure. Prior practice with models did not boost student confidence during their live gastrotomy session. The autotutorials (ATs) were well received by students but did not sufficiently address how to manage mucosal eversion, suture tension, and bleeding encountered during live gastrotomy. AT viewing lime positively correlated with mean total video score for Group T during both sessions. None of the students had prior experience performing hollow organ closure and no significant difference in experience level was evident between groups. Mean closure time was not significantly different between groups for session one (Group T, mean, 31.5 minutes, range, 18.4 to 53.4; Group S, mean, 28.2 minutes, range, 16.8 to 36), but was significantly reduced for session two (Group T, mean, 21.3 minutes, range, 13.9 to 31). This AT/simulator program does not significantly influence students' overall gastrotomy closure technique; gross and video evaluation scores were not significantly different between groups. Without instructor supervision, an additional gastrotomy experience did not improve surgical technique appreciably for Group T; however, these students performed the second procedure with more confidence and speed. Instruction during simulator or live animal practice appears to be necessary to assure adequate skill mastery and to reduce perpetuation of mistakes.     

包膜/抑制剂联合调控对农田土壤N2O排放和氨挥发的影响

采用密闭式静态箱-气相色谱法和通气法研究了盆栽试验条件下包膜/抑制剂结合型肥料对土壤N_2O排放和氨挥发的影响。结果表明:与普通尿素(U)相比,包膜/抑制剂结合型尿素(T2~T4)延迟了土壤N_2O排放和氨挥发出现峰值的时间。包膜尿素(T1)、含有抑制剂的包膜尿素(T2)、抑制剂涂层尿素后包膜(T3)、包膜尿素与抑制剂混合(T4)处理N_2O累积排放量比U处理显著减少了27%、39%、49%、39%(P0.05),T3处理N_2O累积排放量最小,为0.87 kg N·hm-2,显著低于其他处理(P0.05),T2和T4处理之间差异不显著(P0.05);包膜/抑制剂型肥料能够减少土壤氨挥发,T3处理氨挥发量最小,为13.68 kg N·hm-2,与U处理相比,T2、T3和T4处理氨挥发量分别显著减少了34%、45%和31%(P0.05);T2和T3处理玉米产量分别比U处理显著提高13.03%和17.98%(P0.05);T3处理氮素利用率最高,为58.22%;成本效益分析结果表明,T3与其他处理相比经济净效益最大,为3 061.6元·hm-2。综上,包膜/抑制剂结合型尿素可以减少土壤N_2O排放和氨挥发的气态损失,提高产量和氮素利用率,其中抑制剂涂层尿素后包膜(T3)处理效果最佳。     

调亏灌溉对荒漠绿洲膜下滴灌马铃薯生长、产量及水分利用的影响

以马铃薯品种青薯168为研究材料,研究了膜下滴灌条件下不同生育期土壤水分亏缺对马铃薯生长、薯块产量与水分利用等指标的影响。在不同生育阶段设置了8个水分亏缺处理(RD1~RD8)和1个充分灌水处理(CK)。结果表明:膜下滴灌调亏灌溉马铃薯产量、收获指数、水分利用效率、灌溉水利用效率等指标受水分亏缺影响显著,块茎形成期轻度水分亏缺RD1效果最佳,产量略有下降,但其水分利用效率、灌溉水利用效率与收获指数分别较其他处理及对照高8.10%~41.57%、3.57%~42.62%、10.16%~34.38%;水分亏缺影响马铃薯各生育阶段耗水量,且亏缺程度越大,生育阶段消耗的水量减少越明显;全生育期马铃薯光合势和叶面积指数变化趋势基本一致,即生育前期缓慢上升,中期快速上升,后期缓慢下降,总体呈现单峰曲线。因此,适度水分亏缺有利于提高膜下滴灌马铃薯产量、水分利用效率、灌溉水利用效率,促进马铃薯生长并改善其水分利用状况。     

绿洲膜下滴灌调亏马铃薯水分生产函数及灌溉制度优化

通过田间试验研究了绿洲膜下滴灌调亏马铃薯各生育期耗水规律及其影响因素,建立了以Jensen模型为基础的水分生产函数并对马铃薯灌溉制度进行了优化。结果表明:块茎膨大期马铃薯水分敏感指数最大,块茎形成期次之,苗期和淀粉积累期较小;块茎形成期轻度调亏对马铃薯产量无显著影响(P0.05),而块茎形成期中度调亏、块茎膨大期轻度和中度调亏对其产量均有显著影响(P0.05);块茎形成期轻度调亏的水分利用效率比块茎形成期中度调亏、块茎膨大期轻度调亏和全生育期充分灌水分别提高了6.2%、8.3%和6.7%;膜下滴灌调亏马铃薯产量随耗水量增加而增加,水分利用效率随之降低,全生育期充分灌水比块茎膨大期中度水分调亏耗水量增加22.4%,产量增加20.4%,水分利用效率降低14.0%。采用遗传算法并结合水分生产函数进行灌溉制度优化,结果表明:河西绿洲区膜下滴灌马铃薯全生育期灌溉定额为225 mm时,产量最高,为43.86 t·hm-2,灌溉水利用效率为19.5 kg·m-2;灌溉制度为苗期灌水20~30 mm,块茎形成期灌水70~75 mm,块茎膨大期灌水100~115mm,淀粉积累期灌水20~25 mm,灌水间隔为7 d。因此,膜下滴灌调亏在降低马铃薯耗水量的同时,提高了水分利用效率,在块茎形成期轻度水分调亏不影响产量,可达到节水增产的目的。     

不同放牧环境下绵羊牧食行为的比较研究

为了研究同品种绵羊在不同放牧环境下的牧食行为差异,在典型草原区沙质草地和高平原草地两种放牧环境下,对四品种双杂交杂种绵羊的牧食行为进行了观察.结果表明:不同放牧环境下绵羊的采食时间和游走时间占放牧时间的80%左右,放牧环境对采食行为有显著的影响.绵羊在沙质草地采食和游走时间占总放牧时间的66.54%和15.63%,在高平原草地为77.49%和7.79%.不同放牧环境下卧息、站立等时间存在显著差异.