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排序方式: 共有1310条查询结果,搜索用时 15 毫秒
51.
为了解结球白菜(Brassica campestris ssp .pekinensis)COR 基因结构特征,设计1对保守简并引物,利用 RT-PCR 和普通 PCR 方法扩增 COR 基因。结果表明:获得冷诱导结球白菜 COR 基因的编码区 cDNA。该基因命名为 BpCOR,预测编码1个由142个氨基酸组成的理论分子量为14.82 kD 的蛋白。BpCOR 蛋白与十字花科其他植物 COR 蛋白高度同源,具有很高的亲水性,且预测能形成α-螺旋-环-螺旋的超二级结构。  相似文献   
52.
The commercial furunculosis vaccine Aquavac Furovac 5 and an autogenous vaccine, based on the challenge strain, induced immune protection in turbot, Scophthalmus maximus (L.), as shown in challenge tests 120 days post-immunization by injection (relative percentage of survival, RPS = 72-99%). This protective effect lasted for at least 6 months post-immunization at appreciable levels (RPS = 50-52%). Neither the autogenous vaccine nor the commercial vaccine was able to induce significant levels of protection against Aeromonas salmonicida in turbot when administered by immersion. Antibody levels were high or moderate in fish vaccinated by injection with the different vaccines and very low in fish vaccinated by immersion. The field results show that delivering an oral boost after the primary vaccination by injection did not enhance protection of turbot against furunculosis and that water-based (autogenous vaccine) and oil adjuvanted (Alpha Ject 1200) vaccines administered by injection conferred similar levels of protection (RPS > 80%) in turbot.  相似文献   
53.
In this study, we evaluated the release of diclofop-methyl and triasulfuron from the roots of foliar-treated ryegrass and wheat. The study with 14C-diclofop-methyl indicated a basipetal translocation of foliar-applied herbicide in wheat and ryegrass. No root exudation from 14C-diclofop-methyl-treated wheat plants was observed, while 20 days after treatment (DAT) 0.2–0.9% of radioactivity absorbed by ryegrass was found exuded in the growing medium. Root exudation was stimulated three to six times by the presence of untreated wheat or ryegrass sharing the growing medium with diclofop-methyl-treated ryegrass. No subsequent uptake of exuded radiolabel by untreated plants (ryegrass or wheat) in the same pot with 14C-diclofop-methyl-treated ryegrass was observed. The study with 14C-triasulfuron indicated a basipetal translocation of foliar-applied herbicide in wheat and ryegrass and also into the growing medium. By 20 DAT, 0.5–4.2% of radioactivity absorbed by wheat or ryegrass was found exuded in the growing medium. The presence of untreated plants (wheat or ryegrass) in the same pot as triasulfuron-treated ryegrass or wheat induced exudation seven to 32 times more. The study also revealed a subsequent uptake of exuded compounds by untreated wheat or ryegrass sharing the medium of 14C-triasulfuron-treated plants. This study has demonstrated for the first time that the root exudation of exogenous compounds can be related to plant arrangement in pots. The implication is that herbicide root exudation and transfer, a form of allelopathy, could be significant in the field. A precise estimation of environmental fate, unexpected ecological side effects and residual activity of herbicides may require quantification of such exudation.  相似文献   
54.
多花黑麦草幼穗分化进程对种子生产性状的影响   总被引:2,自引:0,他引:2  
两年分期播种试验结果表明,多花黑麦草幼穗分化进程对穗部性状和种子产量有显著影响。幼穗分化的天数与每穗种子粒数呈极显著正相关。播种愈早,幼穗分化天数愈多,种子产量愈高。南京地区留种的多花草麦草的最佳播期为8月20日至9月10日。二棱期是多花黑麦草通过春化阶段的形态标志,也是幼穗能否分化完全的转折点。单棱至护颖分化期是影响种子粒数最关键的时期。  相似文献   
55.
贝珠潮  赵岷阳 《草业科学》1993,10(2):45-47,52
本文通过用沙棘、白榆、刺槐叶粉加工成的颗粒饲料进行的喂兔试验,探讨了这三种树叶作为林业饲料的开发价值。  相似文献   
56.
草坪型多年生黑麦草生殖特性及种子产量构成的研究   总被引:6,自引:2,他引:4  
草坪型多年生黑麦草开花持续期为 33d ,一般情况下穗轴中部的小穗先开花 ,以后逐渐向顶部和基部发展 ;一个花序上的小花开花大部分集中在前 6d ,大约占 89 3% ;多年生黑麦草花后 2 6~ 2 7d ,小穗干重最大 ,其含水量为 41 1 5 % ,种子不易落粒 ,为种子适宜收获期。在种子生产方面 ,构成因子 (株穗数 ,小穗数 )与影响因子 (株高 ,叶重 )共同对草坪型多年生黑麦草的种子产量起作用  相似文献   
57.
Two annual ryegrass (Lolium multiflorum Lam.) cultivars differing in Al sensitivity were grown in nutrient solution at pH 4.2 to assess the effects of temperature (10/6 and 22/18 °C day/night), Mg (0.1 and 1 mM) and Al solution concentrations (0, 3.7 and 74 μ M) on several factors influencing grass tetany potential of forage. Added Al depressed Mg and Ca shoot concentrations and increased shoot K/(Ca + Mg) equivalent ratio especially after prolonged treatment at higher temperature and lower Mg solution concentrations. These effects were more pronounced in the relatively Al-sensitive cultivar Wilo which appeared to be less Mg-efficient as well. Grass tetany potential will therefore be higher following a temperature rise if Al-sensitive ryegrass is grown in a medium containing low Mg and high Al levels.  相似文献   
58.
G. Kleijer 《Plant Breeding》1987,99(2):144-150
Meiotic observations of 56-chromosome plants of the C1, C2 and C3 generations of the amphidiploid Lolium multiflorum × Festuca arundinacea showed that most of the chromosomes paired as bivalents. However, uni- and multivalents were frequently observed. No difference in meiotic regularity and stability could be detected between the different generations. The average chromosome number and; the percentage of 56-chromosome plants decreased with increasing generations. The direct use of the 56-chromosome amphidiploids of L. multiflorum and F. arundinacea in a breeding programme appears to be quite difficult, but these plants can be used in a backcross programme with Lolium and Festuca.  相似文献   
59.
V. Ivandic    W. T. B. Thomas    E. Nevo    Z. Zhang  B. P. Forster 《Plant Breeding》2003,122(4):300-304
A total of 33 simple sequence repeats (SSRs) was analyzed in 52 genotypes of Hordeum spontaneum originally collected from two different soil types (Terra rossa and Basalt) at Tabigha in Israel. Data on the performance of developmental, morphological, and yield‐related traits under well‐watered control and water‐stress conditions were available from previous experimentation, and powdery mildew susceptibility was scored. Regression analyses based on SSR allele class differences were performed. Highly significant associations were detected at the SSR loci Bmac181 (on chromosome 4H) and Bmac316 (6H) for water ‐stress tolerance and powdery mildew resistance, respectively. The study shows that association mapping using SSRs and genetically diverse germplasm provides an effective means of relating genotypes to complex quantitative phenotypes.  相似文献   
60.
Summary In vitro tillers of over 1000 genotypes from nine contrasting Lolium perenne cultivars were cultured on various media containing the synthetic cytokinin, 6-benzylaminopurine (BAP), in order to determine the effect on tillering. The cultures were assessed after seven weeks for survival, tiller production, size and vigour. Added auxins 2,4-dichlorophenoxyacetic acid (2,4-D) and -napthaleneacetic acid (NAA) had no consistent beneficial effects.A significant relationship was found between in vitro tiller production and cultivar heading date. Genotypes of early-heading, less persistent cultivars produced more tillers than genotypes from late heading more persistent cultivars. This was consistent with the generally higher in vitro tiller production in the biennial species Lolium multiflorum cultured on similar media.  相似文献   
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