5种野生无髯鸢尾种子休眠与萌发特性研究

摘要

以5种野生无髯鸢尾种子为材料,从种子的吸水率和发芽率两个方面分析休眠原因与打破休眠促进萌发的方法,为中国鸢尾属植物的种质资源保护与应用提供技术支持.结果表明:(1)5种野生无髯鸢尾种子的吸水率比较显示,玉蝉花和山鸢尾的种皮透水性最好,其次是燕子花的种皮透水性,溪荪的种皮透水性最差;种皮的透水、透气性差及致密的胚乳是抑制马蔺种子萌发的主要原因;另外,变温可增加野生无髯鸢尾种子种皮和胚乳的透水性.(2)马蔺和溪荪种子的种皮对萌发存在强烈的抑制作用,而燕子花、山鸢尾和玉蝉花种子的种皮抑制作用不显著;珠孔端胚乳是5种野生鸢尾种子休眠的主要因素.(3)温度对5种野生无髯鸢尾种子萌发影响很大,变温处理显著提高了马蔺、溪荪、玉蝉花种子的萌发率,且最适条件为:变温30℃/20℃、8h光照/16 h黑暗,但该条件对山鸢尾和燕子花种子萌发的影响不显著,即单一因子不能打破燕子花和山鸢尾种子的休眠.研究发现,5种野生无髯鸢尾种子休眠和萌发特征各异,主要影响因素也不尽相同,但珠孔端胚乳是5种野生无髯鸢尾种子休眠的主要因素;低温层积处理与变温30℃/20℃相结合能明显提高野生无髯鸢尾属种子的发芽率,是其种子打破休眠的有效措施.%Five kinds of seeds of beardless Iris species were used as materials.The purpose of this study was to understand the reasons of seminal dormancy and germination method through conducting the absorbent and germination experiments.This can provide technical support for the protection and application of Iris germplasm resources.The results are as followed:(1) the results of water-absorbing of five wild Apogons Iris seed showed that the water permeability of I.ensata Thunb.and I.setosa Pall.was the best,followed by I.laevigata Fisch,while the water permeability of I.sanguinea Donn.ex Horn.was poor.The permeability to water and gas and density of the endosperm is one of the main reasons for the inhibition of seed germination of I.lactea Pall.var.chinensis Kodiz..In contrast,the dense endosperm is the main factor affecting the germination of the seeds,and the alternating temperature can increase the permeability of the seed coat and endosperm.(2) There was a strong inhibitory effect on seed coat of I.lactea Pall.var.chinensis Kodiz.and I.sanguinea Donn.ex Horn.for germination,while the inhibition of seed cost of I.laevigata Fisch.,I.ensata Thunb.and I.setosa.Pall.was not significant.The tipped micropylar endosperm is the main factor in the dormancy of five wild Iris.(3) The effects of temperature influenced seed germination of Iris greatly,alternating temperature significantly or very significantly increased seed germination rate of I.lactea Pall.var.chinensis Kodiz.,I.sanguinea Donn.ex Horn.,I.ensata Thunb.,and the optimum alternating temperature was 30 ℃/20 ℃,8 h light/16 h dark,but seed germination rate,germination energy of I.setosa Pall.and I.lactea var.chinensis Kodiz.had not significant difference,therefore,the single factor could not break the seed dormancy of I.laevigata Fisch.and I.setosa Pall..A study found that seed dormancy and germination characteristics in five species of wild Apogons Iris were different,the main influencing factors were different,but the tipped micropylar endosperm is the main factor in the dormancy of five wild Iris.It needed to adopt comprehensive measures with cold stratification combined alternating temperature 30 ℃/20 ℃,which was the effective measures on breaking seed dormancy to greatly enhance the wild Apogons Iris seed germination rate.