But seed orchards are difficult to control , because tree pollen spreads so far that alien , non - elite trees almost inevitably muddy the gene pool 但是有種子的果樹(shù)很難控制,因?yàn)榛ǚ蹅鞑サ奶h(yuǎn)了,一些其它種類的樹(shù)木就會(huì)不可避免地弄亂此基因庫(kù)。
Surface - enhanced raman spectra are presented for tree pollen ( cottonwood and redwood pollen ) and a bacterium ( escherichia coli ) , and the e . coli spectra are compared with results obtained from the literature and with results obtained previously by mixing various concentrations of the bioanalyte with the silver colloid 增加表面積后之拉曼光譜發(fā)現(xiàn)于樹(shù)花粉(棉白楊及紅杉)及一種細(xì)菌(大腸桿菌) ,將大腸桿菌之光譜與文獻(xiàn)中及一系列混和濃度之光譜進(jìn)行比較。