But seed orchards are difficult to control , because tree pollen spreads so far that alien , non - elite trees almost inevitably muddy the gene pool 但是有種子的果樹很難控制,因為花粉傳播的太遠了,一些其它種類的樹木就會不可避免地弄亂此基因庫。
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)于樹花粉(棉白楊及紅杉)及一種細菌(大腸桿菌) ,將大腸桿菌之光譜與文獻中及一系列混和濃度之光譜進行比較。