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牧草种子生产中的潜在种子产量与实际种子产量 总被引:25,自引:0,他引:25
本文介绍了牧草种子生产中的潜在种子产量(理论种子产量)、表现种子产量和实际种子产量(收获种子产量)等概念。分析了牧草实际种子产量与潜在种子产量之间的差距及主要原因,同时提出了提高牧草实际种子产量的措施。 相似文献
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在分析内蒙古额克托旗地区苜蓿种子生产基地土壤有效硼含量的基础上,连续2年在不同年限的紫花苜蓿(Medicago sativa)上采用质量分数为0.229%,0.371%和0.600%的硼砂溶液进行花期叶面喷施,研究其对苜蓿种子产量和质量的影响,旨在为苜蓿种子生产微肥施用方面提供科学依据。结果表明:硼对成熟期苜蓿单株叶重和荚果重、种子产量组分、种子产量和质量有一定影响,其中单株叶重以喷施0.600%的硼砂溶液效果最好,2013和2014年分别比对照增重80.77%和35.71%,0.371%的硼砂溶液对增加单株荚果重、单株结荚花序数、每花序结荚数、每荚果种子数以及种子增产效果最显著,2013和2014年种子单产分别为604.38和322.76 kg·hm-2,比对照增产71.35%和37.37%,正常种苗百分比分别比对照提高10.24%和21.11%,种子硬实率分别比对照降低5.16%和10.55%。因此叶面喷施合适浓度硼肥可促进生殖分配,显著提高苜蓿种子产量和正常种苗数,降低硬实率,综合考虑以质量分数为0.371%肥液效果最佳。 相似文献
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草木樨种子成熟过程中的活力特性及产量形成 总被引:4,自引:0,他引:4
草木樨种子成熟过程中活力特性和产量形成机制研究的结果表明,种子在盛花后45d达到生理成熟,其荚果干重和种子活力最高。种子硬实率随着成熟度的加深而提高。新收获的高硬实种子可用种子浸出液电导率和TTC法测定活力。浓硫酸浸泡20~30min可有效可友硬实。种子最高产量在盛花后36d获得,种子适宜收获期是盛花后33~42d。 相似文献
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灌溉对高羊茅种子产量和质量的影响 总被引:7,自引:0,他引:7
以猎狗5高羊茅为材料,研究了在施肥量相同的情况下不同的灌水量和灌水时间对高羊茅种子产量和质量的影响,结果表明,从返青到种子收获,灌4次水(返青期、拔节期、抽穗期和灌浆期灌水,每次灌水量为900m^3/hm^2)生殖枝/m^2最高,小穗数/生殖枝、小化数/小穗、种子数/小穗接近最高;潜在种子产量、表现种子产量和实际种子产量最高,在种子发育早期(盛花期后7d),灌4次水种子标准发芽率最高,老化发芽率最高,种苗芽长最长,芽重最重。种子发育后期,不同的灌溉处理对高羊茅种子质量的影响不明显。 相似文献
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灌溉与密度对沙打旺种子产量及其构成因素的影响 总被引:1,自引:0,他引:1
研究灌溉时间和灌溉比例对沙打旺(Astragalus adsurgens)种子产量及其构成因素的影响。结果表明:在灌溉总量相同的情况下,灌溉方式对沙打旺种子产量构成因素及实际种子产量的影响较大;开花期灌溉900m3/hm2,潜在种子产量和实际种子产量分别为1611.1与333kg/hm2,比对照(CK)分别提高105.7%和73.1%;在现蕾期和开花期灌溉450 m3/hm2,潜在种子产量和实际种子产量分别为1353.6和258.2kg/hm2,比CK提高72.9%和34.2%;穴栽行株距1.0 m,潜在种子产量达1022.4kg/hm2,实际种子产量为269.8 kg/hm2,比行株距1.5m(717.4和176.8 kg/hm2)分别提高42.5%和52.6%;条播中,行距115cm,潜在种子产量达1657.4kg/hm2,与行距75cm(1310.6kg/hm2)和90cm(1152.4 kg/hm2)相比,分别提高26.5%和43.8%,而行距115cm,实际种子产量为337.2kg/hm2,与行距75cm(316.2 kg/hm2)和90cm(223.4kg/hm2)相比,分别提高6.6%和50.9%。 相似文献
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穴播条件下株行距对紫花苜蓿种子产量和质量的影响 总被引:6,自引:1,他引:6
在甘肃省酒泉市研究了穴播条件下不同株、行距处理对紫花苜蓿种子生产性能的影响,结果表明:在产种第一年(2004年)行距和株距对种子产量和产量构成因素均产生了显著的影响(P〈0.05),随着行距从60cm递增至100cm,种子产量也随之从1240kg/hm^2下降到982kg/hm^2,而各株距处理的种子产量则从15cm的1426kg/hm^2依次递减至60cm的807kg/hm^2;行距60cm和株距15cm组合的产量最高,为1833kg/hm^2,100cm行距和株距60cm组合的产量最低,为753kg/hm^2。株行距的增加显著降低了枝条密度,但结荚花序数/枝条和荚果数/结荚花序却显著提高。品种间种子产量的差异不显著。品种间的结荚花序数/枝条、种子重量、正常种苗率、发芽势和硬实率存在显著的差异(P〈0.05)。 相似文献
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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
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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
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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
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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
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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