首页 | 本学科首页   官方微博 | 高级检索  
   检索      


Influence of the Seed Envelope and Growth Regulators Upon Seed Dormancy in Witchweed (Striga lutea Lour.)
Authors:EGLEY  G H
Institution:Plant Science Research Division, Agricultural Research Service, U.S. Department of Agriculture, Whiteville North Carolina, U.S.A.
Abstract:Seed of the angiospermous parasite, witchweed (Striga luteaLour.), normally germinate poorly or not at all unless adequatelypretreated and exposed to a germination stimulant which is obtainedfrom plant root exudates. Under certain conditions, scarificationof the seed envelope promoted germination in the absence ofthe stimulant. With adequately (2-week) pretreated seed, a cutor puncture through the aleurone at the radicular end inducedtypical germination. A puncture through the aleurone elsewhereon the seed induced little or no germination. A cut throughthe aleurone at the cotyledon end or centre of the seed inducedatypical germination. A puncture through the aleurone elsewhereon the seed induced little or no germination. A cut throughthe aleurone at the cotyledon end or centre of the seed inducedatypical germination in which the radicle elongated but didnot penetrate the intact envelope over the radicle. Incubationin oxygen did not promote germination regardless of the siteof seed scarification. Ten per cent carbon dioxide reduced thegermination of punctured seed. Seed germinated equally wellwhen scarified over the radicle and incubated in air, nitrogen,darkness, or light. Brief treatments with sulphuric acid alsoinduced germination. The softening effect of stimulatory acidtreatments upon the aleurone was first evident 6 h later andonly occurred at the radicular end of the seed. Indol-3yl-aceticacid inhibited and ethylene stimulated germination of scarifiedand non-sacrified seed. Gibberellic acid(GA3) had no apparenteffect upon nonscarified seed but promoted germination of scarifiedseed. Inadequately (I-day) or excessively (12- to 16-week) pretreatedseed germinated poorly or not at all when treated with the germinationstimulant, ethylene, GA3, or sulphuric acid. Some seed germinatedslowly when scarified over the radicle, but the germinationrates and totals were less than those of scarified seed pretreatedfor 2 weeks. Additions of stimulant, ethylene or GA3, aceleratedthe germination rates of scarified but inadequately pretreatedseed. Of the treatments tested, only GA3, increased the slowgermination of the excessively pretreated scarified seed. Results indicated that the aleurone restrained radicle elongation.Scarification over the radicle removed the restraint and permittedradicle emergence. However, the ability of the radicle to elongate,as influenced by time of seed pretreatment and exogenous stimulant,GA3 or ethylene, determined whether or not the scarified seedgerminated.
Keywords:
本文献已被 Oxford 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号