棉花植株中的单宁测定方法研究

Determination of tannin in cotton plant

通过 3种方法测定棉花组织中单宁含量比较表明 ,Folin酚还原法测定的 4个品种不同组织和不同生育期顶叶的含量显著高于正丁醇盐酸法 (即花色素反应 ,专门用于缩合单宁的测定 )近 2倍 ,说明这种方法测定出的是相对总酚含量 ,用于表达棉花缩合单宁的含量是不合适的 ,而香草醛法测定结果与正丁醇盐酸法差异不显著 ,可用于棉花组织单宁含量的测定 .在棉花各个组织中 ,花萼、铃皮和叶片缩合单宁含量较高 ,陆地棉中一般达 5 %～ 10 % ;花瓣、花柱子房和铃心中含量较低 ( 2 %左右 ) .顶端嫩叶缩合单宁含量从苗期 ( 1%以下 )起不断增加 ,至吐絮期达最高 ( 10 %左右 ) 。

Three methods were used to determine the tannins content in cotton plant tssues.The tannin content in different organs and terminal leaves of four cotton varieties at different growth stages determined by the Folin's assay was nearly two folds as much as that determined by acid butanol assay,indicating that the Folin's assay only offers the total phenol content,but is not suitable for determining the content of condensed tannin in cotton.There was no significant difference between the results of vanillin assay and acid butanol assay,and hence,it is feasible to use vanillin assay to test the tannin content in cotton.Determinations at boll stage showed that the content of condensed tannin in calyx,boll shell and leaf was rather high,generally up to 5～10%,while that in petal,stigma,ovary and inner boll was lower(about 2%).The condensed tannin content in terminal leaf continually increased from seedling(<1%)to boll stage(10% or so),indicating that the increased tannin content is closely related to the maturity,decrepitude and lignification of cotton tissues.