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本文报道了紫参（ＳａｌｖｉａｃｈｉｎｅｎｓｉｓＢｅｎｔｈ）、马铃薯（ＳｏｌａｎｕｍｔｕｂｅｒｏｓｕｍＬ．）、水稻（ＯｒｙｚａＳａｔｉｖｅＬ．）佛手（Ｃ、ＭｅｄｉｃａＬ．ｖａｒｓａｒｃｏｄａｃｔｙｌｉｓＳｗｉｎｇｌｅ）组织培养再生植株的染色体研究。结果表明：组培植物茎尖中的分裂相多于根尖。组培植物取材方便、材料丰富、不受生长周期限制，适用范围广。佛手染色体数属首次报道。 相似文献
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钟有为 《安徽农业大学学报》2005,(5):16-19,23
中国20多年发展的历程表明:中国己经走上“和平崛起”之际。中国为“和平崛起”正倡导并形成一整套适应世界潮流的国际关系新理念，即和平与发展的时代观以和为贵”、“和而不同”的文化价值观、互信互利平等协作的新安全观、公正合理的国际新秩序观，异国际关系民主化以及“以邻为伴”、“与邻为善”的新睦邻政策.在这些国际关系新理念支撑下正在崛起的中国就能够使世界各国充分相信中国是在维护世界和平中发展自己，并以自身的发展来促进世界和平。 相似文献
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RM ONG JP MORRIS JK O'DWYER JL BARNETT PH HEMSWORTH IJ CLARKE 《Australian veterinary journal》1997,75(3):189-193
Objective To measure acute pain in sheep, based on a human pain model, and examined changes in both electroencephalogram frequency spectrum and behavioural responses to increased electrical stimulation in sheep. Design Analysis of variance (treatment and animal effects) for stimulus intensity where each animal received each electric shock treatment given in the order 0, 5,10 and 20 mA. Procedure Eight sheep with electrodes implanted over the surface of the brain were examined for escape-avoidance and electroencephalogram responses to four levels of electrical stimulation from 0–20 mA. Results With increasing stimulus intensity at the time of feeding, the sheep were more hesitant to return to the feeder or remain near the feeder following stimulation. There was little difference between the 0 and 5 mA stimuli for any of the behaviour variables (P > 0.05). However, there were marked increases in the time taken to re-approach the feeder after receiving an electric shock of 5 mA and of 20 mA (P < 0.05; mean values 3 and 119 s, respectively) and remaining near the feeder for 5 s (P < 0.001; mean values 10 and 167 s, respectively). Following the stimulus, there was an overall increase in the electroencephalogram power spectrum in the first four seconds, which then rapidly returned to normal. In particular, the 20 mA stimulus resulted in higher absolute power values than in the control (0 mA) treatment for delta 2 (P < 0.001), theta 1 (P < 0.05), theta 2 (P < 0.05), alpha 1 (P < 0.001), alpha 2 (P < 0.001) and beta 1 (P < 0.01) band-widths. Similarly, for the 10 mA stimulus, the absolute power values were greater than the control treatment for delta 2 (P < 0.05), alpha 1 (P < 0.01), alpha 2 (P < 0.001) and beta 1 (P < 0.01) bandwidths. Conclusion The experiment suggests that a human acute pain model is applicable to sheep and that these electroencephalogram changes may provide a good measure of acute pain in sheep. 相似文献
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The causes of tiller death in a 2-year-old perennial ryegrass sward were examined between April and August 1977. Physiological causes accounted for most tiller deaths and grazing by slugs and rodents was more important than the damage caused by stem-boring larvae. Tillers which died were mainly small and vegetative, although some flowering tillers died prematurely. Low nutrient status delayed but did not prevent tiller death. Using 14CO2 it was shown that small tillers fixed relatively less radiocarbon than did larger tillers and they did not receive much support for their carbon economy. Selective defoliation showed that in April defoliated tillers imported radiocarbon from undefoliated tillers but that in July at anthesis an undefoliated reproductive tiller retained most of the carbon it fixed, despite its vascular association with defoliated tillers. It appears that much of the tiller death during the period April-August is due to the failure of the more favourably placed tillers to support other tillers which are heavily shaded. 相似文献
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The effect of nutrient concentration on the reproductive development and seed yield of Poa annua was examined in a sand culture experiment. The nutrient concentration during the initial vegetative stage did not affect the time taken for double ridge formation by the main shoot but did influence the subsequent development of the inflorescence as did the post-initiation level of nutrients. At low nutrient levels flowering was inhibited in some individuals but at the higher concentrations inflorescence emergence was hastened, inflorescence size was increased and, in particular, the number of spikelets and hence the number of seeds per inflorescence was greatly increased. The mean weight of 100 seeds was unaffected by the nutrient concentration. The number of reproductive tillers per plant was increased by high nutrient supply but the proportion of dry weight allocated to root development was reduced. 相似文献
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【目的】了解不同披碱草种质性状,为优良披碱草种质材料筛选提供依据。【方法】以21份不同来源的披碱草种质为材料,通过测定17个农艺指标,利用相关性分析、主成分分析、多元逐步回归分析、聚类分析等统计分析方法,研究披碱草主要农艺性状的变异特征,明确披碱草产量形成的主要影响因子。【结果】披碱草农艺性状变异丰富,变异系数在11.07%（花序长）～45.53%（基部茎长）。相关性分析表明,披碱草单株干草产量与基部茎长、旗叶长呈显著正相关（P<0.05）,单株种子产量与分蘖数、千粒质量呈极显著正相关（P<0.01）。多元逐步回归与通径分析表明,株高、茎粗、基部茎长、穗下茎长、旗叶宽、倒二叶长、倒二叶叶鞘长、倒二叶宽、花序长、小穗长、茎叶比是影响单株干草产量的主要因子,其中茎粗、基部茎长、穗下茎长、旗叶宽、倒二叶叶鞘长、小穗长、茎叶比对单株干草产量的影响有直接效应;株高、倒二叶叶鞘长、小穗长、分蘖数、千粒质量是影响单株种子产量的主要因子,其中小穗长、分蘖数对单株种子产量的影响有直接效应。主成分分析表明,前5个主成分累积贡献率达79.304%。根据第1,2主成分筛选出PJC09、PJC14、PJC15、PJC17、PJC18、PJC26、PJC27共7份单株干草产量和单株种子产量表现均较高的披碱草种质材料,其平均单株干草产量为197.02 g,单株种子产量为21.39 g。聚类分析表明,21份披碱草种质材料被聚为3类,第Ⅰ类包含2份种质材料,可作为筛选单株种子产量高的种质利用,第Ⅱ类包含10份种质材料,可作为筛选单株干草产量和单株种子产量均高的种质利用,第Ⅲ类包含9份种质材料,可依据育种目标筛选特异性状的种质利用。【结论】确定了11个影响披碱草单株干草产量的主要因子和5个影响单株种子产量的主要因子,筛选出单株干草产量和单株种子产量均表现优异的7份披碱草种质材料。 相似文献
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The physiology of tiller death in grasses. 总被引：2，自引：0，他引：2
C. K. ONG 《Grass and Forage Science》1978,33(3):197-203
A reproducible method of causing tiller death on individual ryegrass (Lolium perenne L., cv. S23) plants is described. This was achieved by subjecting whole plants grown previously for 7 weeks in full light (100%) and full nutrient (100%) to either light stress (17.5% or 2.5%) or nutrient stress (10% or 0%) or various combinations of light and nutrient stress. Detailed records were made of tiller appearance, position and weight, and the probability of tiller death was calculated. Analysis of each plant indicated that the smallest tiller, which was often, but not always the youngest, was the most vulnerable when the whole plant was stressed. Tiller position was relatively unimportant in determining survival. The results are discussed in relation to tiller mortality in natural populations and crop communities. 相似文献
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籼型两用核不育水稻育性转换过程中氧代谢的变化 总被引：2，自引：0，他引：2
以籼型两用核不育水稻GD1S 和N19S 及常规水稻粳籼89为材料, 研究了自然条件下不同光温引起两用稻育性转换时活性氧清除系统的变化。实验结果表明: 3月上旬播种在长日高温下发育的两用稻出现败育, 各生育期的剑叶、幼穗，完熟期的颖花和花药中AsA(抗坏血酸)和GzSH(谷胱甘肽)含量均低于同期播种的粳籼89。在7月中旬播种生长发育期遇短日低温的两用稻呈可育态, 这时AsA、GSH含量明显高于粳籼89。抗氧化酶活性在可育状态的两用稻中其活性也均高于同期播种的粳籼89。在两种光温条件下发育的两用稻在各生育期的剑叶中POD(过氧化物酶)活性均高于同期播种的粳籼89, 只是短日低温下发育的两用稻与粳籼89之间POD活性之差更显著。长日高温引起籼型光温敏核不育系水稻的败育与剑叶和幼穗中活性氧清除能力的下降、活性氧产生与清除之间的失衡导致氧代谢的失调有一定的关系。 相似文献
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