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Golden rice     
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Micronutrients are essential for a healthy life. Humans do not produce micronutrients, and hence they must obtain them through the foodchain. Staple crops are the predominant food source of mankind, but need to be complemented by other foodstuffs because they are generally deficient in one or the other micronutrient. Breeding for micronutrient-dense crops is not always a viable option because of the absence of genetic variability for the desired trait. Moreover, sterility issues and the complex genetic makeup of some crop plants make them unamenable to conventional breeding. In these cases, genetic modification remains the only viable option. The tools to produce a number of micronutrients in staple crops have recently become available thanks to the identification of the genes involved in the corresponding biochemical pathways at an unprecedented rate. Discarding genetic modification as a viable option is definitely not in the interest of human wellbeing.  相似文献   

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《Journal of nematology》2004,36(4):421-423
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No Golden Ages     
《CMAJ》1961,84(20):1140-1141
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Golden rice and beyond   总被引:13,自引:0,他引:13  
Potrykus I 《Plant physiology》2001,125(3):1157-1161
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It is 70 years since the embryologist Warren Lewis noted the fundamental importance of adhesion to development and physiological function (Lewis, 1922). He wrote: “Were the various types of cells to lose their stickiness for one another and for the supporting extracellular white fibers, reticuli, etc., our bodies would at once disintegrate and flow off into the ground in a mixed stream of ectodermal, muscle, mesenchyme, endothelial, liver, pancreatic, and many other types of cells.” Underlying this striking piece of imagery are a number of remarkable phenomena: (1) in order to differentiate in the first place, cell precursors to those tissues had to adhere to each other, (2) cell adhesion and cell movement had to be coordinated in time and space, and (3) the physiology of both the cells and the tissues to which they contribute depends critically on the appropriate ordering of adhesion events.  相似文献   

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秦岭羚牛的食性   总被引:19,自引:6,他引:13  
在佛坪自然保护区对秦岭羚牛的食性研究中,记录到羚牛采食161种植物,其中草本占32.9%,木本占62.7%,苔藓植物和蕨类植物牛4.4%。羚牛的食物呈季节性变化,它采食的植物种类在春季、夏季比秋季多、冬季多。羚牛是广食性的植食动物,但它对所采食植物的部位具有一定的选择性,主要以采食植物的嫩枝叶为主,同时还有啃食树皮的习性。野外见到羚牛以直接饮水或舔雪的方式来补充对水份的需求。  相似文献   

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Molting of Rotylenchus buxophilus is similar in all observed post-embryonic stages. During molting the old cuticle and cephalic framework, conus of the old stylet, vestibulum extension, linings of amphids, distal part of the linings of the excretory duct, rectum, and phasmids are shed. The new styler is formed starting from the conus, which is simultaneously formed in its entirety.  相似文献   

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《Ibis》1944,86(3):409-409
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秦岭羚牛的采食行为   总被引:8,自引:1,他引:7  
从集群、迁移、时间、方式、饮水和舔盐 6个方面报道了秦岭羚牛的采食行为。羚牛主要以集群的方式在白天采食 ,也见到羚牛单独采食及在夜间活动采食的情形。研究期间集群活动的羚牛个体数占所见羚牛总数的 95 4% ,有 5 0 %以上的羚牛是在大于 1 5只的羚牛群体中见到的。头牛在羚牛群体的采食迁移过程中起着重要的作用。它通过发出低沉的吼叫声来使牛群聚集在一起并共同采食迁移。随着食物的季节性生长变化 ,羚牛具有季节性上下垂直迁移采食的习性。羚牛采食时 ,多用上下唇扯断植物的枝 (茎 )叶 ,而不是以舌卷食 ,也用牙咬或啃食木本植物的幼枝或皮。羚牛有多种采食方式 ,一般是以常规行走的方式采食。但当食物超出正常采食方式所能获得的特殊情况下 ,羚牛会采用一些特殊的方式取食 ,包括后肢站立采食、骑树采食、压枝采食、撞击采食和跪地采食。  相似文献   

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