非侵入性木本植物栽培需谨慎
文章来源:未知 文章作者:enread 发布时间:2011-10-10 03:45 字体: [ ]  进入论坛
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Cultivars(栽培品种) of popular ornamental1 woody plants that are being sold in the United States as non-invasive are probably anything but(根本不) , according to an analysis by botanical(植物学的) researchers published in the October issue of BioScience. Tiffany M. Knight2 of Washington University in St. Louis, Missouri, and her coauthors at the Chicago Botanic Garden write that the claims of environmental safety are in most cases based on misleading demographic evidence that greatly underestimates the plants' invasive potential. What is more, the offspring of cultivars do not usually "breed true" and may be more fecund3(肥沃的) than their parents, especially if they cross with plants from nearby feral populations. Many invasive plants were once ornamental cultivars, because the characteristics that the "green" industry looks for are the same ones that make a plant potentially invasive -- being adaptable4 to wide range of conditions, forming dense5 stands good for erosion control, and having a long flowering period, for example. In recent years the nursery and horticultural industries have responded by creating cultivars of top-selling plants that produce reduced numbers of viable6 seed and are advertized as "safe to natural areas." Such cultivars of Japanese barberry, buckthorn, and burning bush are now widely sold, as they avoid bans on growing invasive species.

Yet simple population modeling demonstrates that reductions of even 95 percent in the number of viable(可行的) seed will leave a long-lived species quite capable of spreading -- and many of the new cultivars do not achieve even that much of a reduction. More sophisticated modeling would likely reveal even stronger invasive potential of the "safe" cultivars. Knight and her co-authors conclude that only completely sterile7(不育的,贫瘠的) cultivars can be considered truly safe without further testing, and that other types should be tested for breeding true and having a low growth rate before they are sold as non-invasive.



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1 ornamental B43zn     
adj.装饰的;作装饰用的;n.装饰品;观赏植物
参考例句:
  • The stream was dammed up to form ornamental lakes.溪流用水坝拦挡起来,形成了装饰性的湖泊。
  • The ornamental ironwork lends a touch of elegance to the house.铁艺饰件为房子略添雅致。
2 knight W2Hxk     
n.骑士,武士;爵士
参考例句:
  • He was made an honourary knight.他被授予荣誉爵士称号。
  • A knight rode on his richly caparisoned steed.一个骑士骑在装饰华丽的马上。
3 fecund PkAxn     
adj.多产的,丰饶的,肥沃的
参考例句:
  • The pampas are still among the most fecund lands in the world.南美大草原仍然是世界上最肥沃的土地之一。
  • They have a fecund soil.他们有肥沃的土地。
4 adaptable vJDyI     
adj.能适应的,适应性强的,可改编的
参考例句:
  • He is an adaptable man and will soon learn the new work.他是个适应性很强的人,很快就将学会这种工作。
  • The soil is adaptable to the growth of peanuts.这土壤适宜于花生的生长。
5 dense aONzX     
a.密集的,稠密的,浓密的;密度大的
参考例句:
  • The general ambushed his troops in the dense woods. 将军把部队埋伏在浓密的树林里。
  • The path was completely covered by the dense foliage. 小路被树叶厚厚地盖了一层。
6 viable mi2wZ     
adj.可行的,切实可行的,能活下去的
参考例句:
  • The scheme is economically viable.这个计划从经济效益来看是可行的。
  • The economy of the country is not viable.这个国家经济是难以维持的。
7 sterile orNyQ     
adj.不毛的,不孕的,无菌的,枯燥的,贫瘠的
参考例句:
  • This top fits over the bottle and keeps the teat sterile.这个盖子严实地盖在奶瓶上,保持奶嘴无菌。
  • The farmers turned the sterile land into high fields.农民们把不毛之地变成了高产田。
TAG标签: species plants invasive
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