共查询到20条相似文献，搜索用时 703 毫秒
1.
20世纪 90年代 ,一些省区竞相发展银杏 ,由于良种嫁接苗供应不足 ,很多地方种植的多为实生苗或劣种嫁接苗 ,种后 10余年尚未结实。对这些银杏树如能实行多头高接换种 ,4年左右可以绝大部分开花结果。高接换种最好在秋季进行。1 秋季嫁接的好处 ①气温适宜 ,嫁接成活率高 ,愈合良好 ,第 2年生长良好 ,一般成活率可达 90 %以上 ,第 2年新梢生长可达 5 0ｃｍ以上。②嫁接时间长。秋季嫁接从 8月中旬至 10月上旬均可进行 ,在两广、湖南南部以及年平均气温 16℃以上的地区可嫁接到 10月中下旬。如一次嫁接不成活 ,可以补接。③嫁接技术容易掌握… 相似文献
2.
笔者1994年间月上旬在永泰县城峰镇一山地果园采取以下技术,对1989年春定植的以劣质羊矢梅为主的530株实生树高接换种成白粉梅,株成活率达11％,芽成活率达95％,1995年10月25日随机抽样10株树测得平均树冠幅东西X南北为2．58mX2．59m,1996年10月6目测定冠幅达3．75mx3,96m,同时长势旺盛。接芽与砧木愈合完好,牢固性较强。高接第2年开始结果,高接4年后累计总产量、产值分别是未高接的2．8和6．9倍。1高接时期与方法12月上旬,在每株高接树上取5－8个主枝、副主校,在离地1－1．2m的直径3－5cm枝条上进行单芽切接,接时剪除其他所有… 相似文献
3.
4.
5.
高接换种是柑桔品改的重要途径之一。但要防止盲目高接 ,走出以下误区。1 不分树龄和树势 如新邵县雀塘镇曾家村有1 1ｈｍ2 尾张温州蜜柑 ,树龄 2 2年。由于管理不善 ,树势较差 ,砧木和树干基部被天牛蛀空 ,根系完全衰老。桔农想通过高接换种来“返老还童” ,于 1999年实施高接 ,接穗品种为椪柑。嫁接后 1个月调查 ,接穗成活率只有 8 2 %。由于去冠后加速了根系衰亡 ,加之洼地霜冻时冷空气下沉 ,成活了的接穗全被冻死 ,连中间砧尾张也被冻死殆尽 ,真是劳民伤财。有鉴于此 ,如高接换种确属必要 ,要选择树龄在 15年以下 ,树势较强 ,桔园管理… 相似文献
6.
１ 高接时期 春、夏、秋季都可进行,以秋季嫁接效果最好。据试验,秋季嫁接成活率达９５％以上;春季嫁接因３月雨水多,成活率低,约为６０％;夏季嫁接温度高,易成活,成活率为８０％。春季嫁接在萌芽前１周内嫁接最佳;夏季嫁接在６月初春梢停止生长木质化后进行,此时嫁接温度高,水分充足,嫁接后愈合快,易成活;秋季嫁接在９月上中旬进行,成活率最高。据对１２年生温州蜜柑高接换种试验,１９９９年秋季分别于９月５日、９月２５日、１０月１０日高接换种脐橙芽各２３６个,２０００年春检查,嫁接成活率分别为９８％、８２％、４… 相似文献
7.
橄榄高接换种是优化橄榄品种结构 ,实现橄榄良种化、区域化 ,提高品质和产量的有效途径。现将四川橄榄高接换种操作技术简要介绍如下。1 选择高接树 橄榄高接树接穗发芽和初期生长主要靠砧木和接穗的贮藏养分。因此 ,在高接换种时要选择树体贮藏养分充足 ,3～ 15年生树 ,树龄过大、树势过弱的树嫁接成活率极低 ,不宜当年高接。2 采集接穗 橄榄单宁含量高 ,接穗一般要求随采随接。试验表明 ,接穗随剪随接 ,成活率高达 90 %以上 ,采后贮藏 5天 ,成活率为 6 5 % ,采后贮藏 7天 ,成活率不足 5 0 % ,接穗存放时间长短 ,对成活率影响很大。同… 相似文献
8.
我县青梅种植面积 2 83 6ｈｍ2 ,由于产量低 (平均176ｋｇ 6 6 6 7ｍ2 ) ,果小 ,品质差 ,商品率低 ,许多果农失去信心 ,大部分梅园已抛荒。为改变我县青梅低产、劣质、低效益现状 ,调动果农积极性 ,2 0 0 0年冬我们在青梅种植面积最大的桃溪镇新礤村梅子坝和亭头村梅园进行了高接换种 ,高接广东省普宁县的白粉梅 ,2 0 0 0年 11月 5日至 12月 3日新礤村高接 6 0 0株 ,成活 5 71株 (据 2 0 0 1年 10月 6日观察 ) ,成活率达 95 1% ,2 0 0 0年 12月 10日至 2 0 0 1年 1月 5日亭头村高接 4 2 0株 ,成活 4 12株 ,成活率达 98% ,且90 %穗梢达到 3… 相似文献
9.
应用高接换种技术改造低龄劣质桃园 ,特别是低龄劣质单株 ,具有投资少、省时、省工、见效快和效益高等特点。若采用重新定植优良单株的方法 ,则因桃忌连作须轮作 2～ 3年其他作物 ,加上恢复树冠需 2～ 3年 ,即要 4～ 6年才能进入丰产期 ,且费工、投资大。高接换种可利用植株原有强大根系和树冠骨架 ,只需 2～ 3年即可恢复改种前产量。高接换种宜采用以春季枝接为主 ,夏季芽接补接为辅的办法。春季枝接较宜控制树形 ,长势旺 ;夏季补接成活率高 ,可嫁接时间长。1 春季高接 采用双芽枝切接或劈接 ,一般在 2月下旬至 3月上旬进行。就近在优良… 相似文献
10.
浙江省慈溪市是全国著名的杨梅之乡 ,主栽品种为荸荠种杨梅 ,占杨梅总面积的 95 %以上。但由于品种单一、成熟期过分集中 ,在一定程度上影响了供应和采收 ,也影响了销售和经济效益。为此 ,我们于 1999年春季 ,对 4～ 12年生的实生杨梅树和部分劣质低产杨梅树进行高接换种试验 ,高接成活率从传统的 2 0 %～ 30 %提高到 85 %以上 ,2 0 0 1年开始投产。现将经验总结如下 :1 高接换种时间一般选在春季 3～ 4月间 ,最适在“清明”前后 5天左右 ,此时气温不高 ,树液开始流动 ,有利于接口愈合成活 ,过早或过迟嫁接都会影响成活率。2 高接基砧的选… 相似文献
11.
12.
魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
13.
14.
本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
15.
REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
16.
17.
18.
Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献
19.
乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制. 相似文献
20.
Billinghurst RC Brama PA van Weeren PR Knowlton MS McIlwraith CW 《American journal of veterinary research》2004,65(2):143-150
OBJECTIVE: To determine whether serum concentrations of biomarkers of skeletal metabolism can, in conjunction with radiographic evaluation, indicate severity of osteochondrosis in developing horses. ANIMALS: 43 Dutch Warmblood foals with varying severity of osteochondrosis. PROCEDURE: 24 foals were monitored for 5 months and 19 foals were monitored for 11 months. Monthly radiographs of femoropatellar-femorotibial and tibio-tarsal joints were graded for osteochondral abnormalities. Serial blood samples were assayed for 8 cartilage and bone biomarkers. At the end of the monitoring period, foals were examined for macroscopic osteochondrosis lesions. RESULTS: Temporal relationships were evident between certain serum biomarkers and osteochondrosis severity in foals during their first year. Biomarkers of collagen degradation (collagenase-generated neoepitopes of type-II collagen fragments, type-I and -II collagen fragments [COL2-3/4C(short)], and cross-linked telopeptide fragments of type-I collagen) and bone mineralization (osteocalcin) were positive indicators of osteochondrosis severity at 5 months of age. In foals with lesions at 11 months of age, osteochondrosis severity correlated negatively with COL2-3/4C(short) and osteocalcin and positively with C-propeptide of type-II procollagen (CPII), a collagen synthesis marker. Radiographic grading of osteochondrosis lesions significantly correlated with macroscopic osteochondrosis severity score at both ages and was strongest when combined with osteocalcin at 5 months and CPII at 11 months. CONCLUSIONS AND CLINICAL RELEVANCE: The ability of serum biomarkers to indicate osteochondrosis severity appears to depend on stage of disease and is strengthened with radiography. In older foals with more permanent lesions, osteochondrosis severity is significantly related to biomarker concentrations of decreased bone formation and increased cartilage synthesis. 相似文献