【作者】 余小芳；

【导师】 周永红；

【作者基本信息】 四川农业大学 ， 植物资源的保护与利用， 2009， 博士

【摘要】 鸢尾属(Iris L.)是鸢尾科(Iridaceae)最大的一个属,为多年生草本,是绿化、美化、香化城市,装饰花坛、花径、花带、路旁及草坪的优良材料。全世界约300种,广泛分布于北温带。我国约产60种13变种及5变型,广布于全国各省,以西南、西北最多。一直以来,鸢尾属植物的分类与系统学都存在很大的争议。争论的焦点主要在于：(1)白花马蔺I. lactea Pall.和马蔺I. lactea var. chinensis (Fisch) Koidz.的分类学问题。基于形态和地理分布的差异,赵毓棠(1985)把马蔺I. lactea var. chinensis (Fisch) Koidz.作为白花马蔺I. lactea Pall的变种。但高宝莼(1985)认为I. lactea var. chinensis (Fisch) Koidz.是白花马蔺I. lactea Pall.的异名。(2)四川鸢尾I sichuanensis Y. T. Zhao、薄叶鸢尾I. leptophylla Lingelsh.和锐果鸢尾I. goniocarpa Baker的分类学问题。赵毓棠(1980)认为四川鸢尾与薄叶鸢尾近似,但花茎较高,花较大,苞片宽披针形或狭卵圆形相区别,是两个不同的物种。但高宝莼(1985)认为四川鸢尾是薄叶鸢尾的异名。锐果鸢尾花与四川鸢尾、薄叶鸢尾极其相似,只是叶片大小上略有区别,很难区分。(3)蝴蝶花I. japonica Thunb.、扁竹兰I. confusa Sealy和扇形鸢尾I. wattii Baker的分类学问题。赵毓棠(1980)报道扁竹兰的花、果与蝴蝶花近似,但有地上茎,叶片丛生于茎顶等特征又与扇形鸢尾近似,三者极易混淆。Waddick (1994)认为蝴蝶花、扁竹兰可能是同一个物种的两个变种。本研究通过形态学、孢粉学、染色体核型分析、细胞核rDNA的ITS区序列分析,探讨了四川省鸢尾属7物种1变种的表型特征、染色体核型、孢粉形态、种内分化变异,为解决长期争议的物种分类处理疑虑提供资料。同时,对11种1变种鸢尾属植物的花粉生活力和柱头可授性,以及4种鸢尾植物的种子休眠与萌发特性进行了研究,为鸢尾属植物种质资源的繁殖及育种创新和利用提供依据。本研究获得的主要结果如下：1.基于27个形态性状,对7种1变种鸢尾属植物进行了表型分支分析。经简约分析,得到了4颗同等最大简约分支树。结果表明：(1)马蔺作为白花马蔺的一个变种来处理比较合适；(2)四川鸢尾和薄叶鸢尾的亲缘关系较锐果鸢尾近；(3)扁竹兰和扇形鸢尾的关系较蝴蝶花更近。2.对9种1变种鸢尾属植物的核型进行了观察和分析,其中四川鸢尾、薄叶鸢尾、锐果鸢尾、白花马蔺、扁竹兰和德国鸢尾的核型为首次报道。这些物种的核型公式如下：四川鸢尾2n=26=12m (4SAT)+12sm (2SAT)+2st;薄叶鸢尾2n=26=14m(2SAT)+10sm(4SAT)+2st;锐果鸢尾2n=26=12m+12sm+2st(2SAT):白花马蔺2n=40=28m+10sm+2st;扁竹兰2n=32=8m+18sm+6st;德国鸢尾2n=40=16m+20sm+4st.金脉鸢尾,鸢尾,马蔺的核型公式分别为2n=40=18m+22sm(2SAT)；2n=28=16m+12sm+6st(6SAT)；2n=40=18m+16sm+6st(6SAT).研究结果表明：(1)马蔺作为白花马蔺的变种是可行的；(2)四川鸢尾、薄叶鸢尾和锐果鸢尾是三个亲缘关系很近的独立物种；(3)扇形鸢尾和扁竹兰、蝴蝶花能从染色体水平上区分开来。3.对四川鸢尾11种1变种进行了孢粉形态学研究。结果显示：(1)白花马蔺和马蔺花粉大小相似,形状、萌发孔、外壁纹饰和网脊形态相同,网脊宽度不同；(2)四川鸢尾、薄叶鸢尾和锐果鸢尾三者之间的花粉形状、外壁纹饰和网脊形态相同,均无明显萌发孔,锐果鸢尾花粉较薄叶鸢尾和四川鸢尾小,表明这3个物种的亲缘关系较近；(3)蝴蝶花和扁竹兰花粉大小基本相同,前者形状为扁球形,后者为近球形；萌发器官、表面纹饰和网脊形态相同,网眼内无颗粒,表明该两物种亲缘关系较近；(4)扇形鸢尾与蝴蝶花和扁竹兰二者相比,在花粉粒大小,表面纹饰均上均有较大差异,表明扇形鸢尾与蝴蝶花和扁竹兰的亲缘关系较远。本研究还讨论了鸢尾属五个亚属的花粉形态特征及演化趋势。4.对四川鸢尾9种1变种的nrDNA ITS序列进行分析,构建了ITS系统发育树。结果表明：(1)采自四川同一地点的白花马蔺和马蔺聚为一个小支,支持率非常高为98%,另外两个来自不同地点的白花马蔺和马蔺间分别聚为两个不同的小支,说明两者间不同地理分布,分化较大；(2)四川鸢尾、薄叶鸢尾和锐果鸢尾三物种聚为一大支,其中四川鸢尾和薄叶鸢尾聚为一小支。说明四川鸢尾和薄叶鸢尾的关系较锐果鸢尾为近；(3)扁竹兰和蝴蝶花聚为一小支,扇形鸢尾单独聚为一支,推测扁竹兰和蝴蝶花的关系比扇形鸢尾要近。5.对10种1变种鸢尾属物种花粉生活力和柱头可授性进行了研究。结果表明：(1)10种1变种鸢尾花粉活力最佳状态均为12：0014：00左右,柱头可授性的最佳状态出现在10：00—14：00左右；(2)花药颜色变化和柱头颜色变化不能表现花粉活力高低和柱头可授性的强弱。6.对4个鸢尾属物种的种子休眠特性进行了研究。结果表明：(1)鸢尾、金脉鸢尾、白花马蔺和扁竹兰4物种没有物理休眠；(2)4物种均为光敏性休眠种子。其中,金脉鸢尾、白花马蔺和扁竹兰3物种在没有光照的条件下,种子不能萌发,会进入强迫休眠状态；(3)金脉鸢尾、白花马蔺和扁竹兰的种皮含有抑制物,3物种具有生理休眠。7.对4个鸢尾属物种的种子萌发特性进行了研究。结果表明：(1)种皮对金脉鸢尾、白花马蔺和扁竹兰发芽的机械阻力较胚乳大。在鸢尾种子中,种子发芽受胚乳的机械阻力大；(2)在鸢尾种子中,种皮对种子的发芽率有促进作用；(3)白花马蔺和扁竹兰对土壤基质要求不高,对环境适应能力很强。鸢尾种子的最适土壤发芽基质为粘土；(4)变温20／30℃是扁竹兰、鸢尾和白花马蔺种子萌发的最佳温度；(5)低温冷层积对促进4物种的种子发芽没有明显效果。更多还原

【Abstract】 Iris L. is a large genus in Iridaceae and involves about 300 species in the world. Because of its beautiful and specially shaped, it is preferable in viewing and admiring as garden plants. Species of Iris are herbs perennial and distributing in the north temperate regions (Goldblatt 1990). There are 60 species,13 varieties, and 5 forms in China, which is a distribution center of Iris (Zhao 1985). The taxonomic status of Iris species are still under discussion today. The main dispute is focus on:(1) the interspecific relationships of I. lactea Pall.and I. lactea var. chinensis (Fisch) Koidz.. Based on their geographical and morphological differences, Zhao (1985) treated I. lactea var. chinensis as a variety of I. lactea. But, Gao (1985) suggested that I. lactea var. chinensis should be a homonymy of I. lactea, not a variety of I. lactea. (2) the relationship among I. sichuanensis Y. T. Zhao, I. leptophylla Lingelsh.and I. goniocarpa Baker. Their morphological characteristics, except the size of leaf, are similar to each other. The taxonomic classification of these three species is always mixed up. Based on the size of leaf, Zhao (1985) suggested that I. sichuanensis and I. leptophylla should be two independent species. However, according to the similar flower and geographic distribution of I. sichuanensis and I. leptophylla, Gao (1985) suggested that I. sichuanensis should be a homonymy of I. leptophylla. (3) the relationship among I. japonica Thunb.,I. confusa Sealy andI. wattii Baker. Zhao (1980) reported that the flowers and fruits of I. confusa were similar to those of I. japonica, while the vegetative parts of I. confusa were similar to those of I. wattii. Waddick (1994) suggested that I. japonica and I. confusa may be the variants of a same species. The relationship between I. confusa and I. wattii were still uncertain (Waddick and Zhao 1992). In order to investigate the relationships of I. lactea, I. lactea var. chinensis; I. sichuanensis, I. leptophylla, I. goniocarpa, I. japonica, I. confusa and I. wattii, morphology, cytology, pollen morphology, and nrDNA internal transcribed spacer (ITS) sequences analysis were used in this study. The stigma receptivity, seed dormancy and germinaton characters of Iris species were also investigated in this study for provide some new theory evidence with propagation and breeding for Iris genus. The main results are as follows:1. A cladistic analysis based on 27 morphologic characters of 7 taxa and 1 variety in Iris species was presented. Maximum parsimony analysis of the aligned sequences yielded 4 maximally parsimonious trees. The results indicated that:(1)I. lactea was closely related to I. lactea var. chinensis; (2)I. sichuanensis was related to I. leptophylla than that to I. goniocarpa; (3) I. japonica had a more close relationship with I. wattii than that with I. confusa.2. Karyotype analysis of 9 taxa and 1 variety in the genus Iris were investigated in this study. The karyotypes of I. sichuanensis, I. leptophylla, I. goniocarpa, I. lactea, I. confusa and I. germanica were reported firstly in this study. The karyotype formulate were: I. sichuanensis,2n=26=12m(4SAT)+12sm(2SAT)+2st;I. leptophylla,2n=26=14m(2SAT) +10sm(4SAT)+2st;I. goniocarpa,2n=26=12m+12sm+2st(2SAT).I. lactea,2n=40= 28m+10sm+2st;I. confusa,2n=32=8m+18sm+6st;I. germanica,2n=40=16m+20sm+4st. The karyotypes of I. chrysographes, I. tectorum and I. lactea var. chinensis were also carried out. I. chrysographes,2n=40=18m+22sm(2SAT); I. tectorum,2n=28=16m +12sm+6st(6SAT);I. lactea var. chinensis,2n=40=18m+16sm+6st(6SAT). The results showed as follows:(1)I. wattii, I. confusa and I.japonica are three independent species; (2) I. sichuanensis, I. leptophylla and I. goniocarpa are three independent species with close relationships; (3) it is reasonable to treat I. lactea var. chinensis as a variety of I. lactea.3. Pollen morphologies of 11 taxa and 1 variety in Iris were investigated under scanning electron microscope. The results showed that (1) except the width of spine, the shape and size of pollen grains, shape of aperture, extine sculpture of I. lactea and I. lactea var. chinensis were similar. (2) the shape of pollen grains, extine sculpture and width of spine of I. leptophylla, I. sichuanensis and I. goniocarpa were highly approximate and no aperture was found among the three species. The pollen grain of I. goniocarpa was smaller than those of I. leptophylla and I. sichuanensis. (3) pollen of I. japonica and I. confusa had similar size and shape, and no grains existed in the meshes of these two species. The shape of pollen grains in I. japonica was suboblate while that in I. confusa was subspheroidal. (4) I. wattii was distinctly different from I. japonica and I. confusa in pollen size and exine ornamentation, suggesting that I. wattii had relatively distant relationship with I. japonica and I. confusa. We discussed briefly the pollen morphological characteristic and evolutionary trend of the five subgenus of Iris.4. To estimate the phylogenetic relationships of Iris species, nuclear ribosomal internal transcribed spacer (ITS) of 10 taxa and 1 variety were analyzed. I. lactea var. chinensis and I. lactea collected from one place were clustered in same clade. The other two species of I. lactea var. chinensis and I. lactea collected from different place were clustered in to two sub-clades. The result indicated that geography differentiation existed in I. lactea var. chinensis and I. lactea. I. leptophylla, I. sichuanensis and I. goniocarpa in one clade. Within this clade,I. leptophylla and I. sichuanensis were clustered in the same sub-clades. The results suggested that I. leptophylla have more close relationship with I. sichuanensis than that with I. goniocarpa. I. japonica and I. confusa were clustered in one clade, and I. wattii was single clustered in one clade. The recults suggested that the relationship of I. japonica and I. confusa were more closely than those with I. wattii.5. Pollen viability and stigma receptivity of 11 taxa and 1 variety of Iris were were estimated in this study. The results indicated that:(1) The best time of pollen viability was appeared in 12:00—14:00 and the best time of stigma receptivity was appeared in 10:00—14:00. (2) All of the anther and stigma colour could not show the pollen viability and stigma receptivity ability.6. Seed dormancy in four Iris species were carried out in this study. The results indicate that:(1) the 4 species of I. tectorum, I. lactea, I. confusa and I. chrysographes were not have physical dormancy; (2) all four Iris species were light sensitive seeds, a light requirement for I. lactea, I. confusa and I. chrysographes for seed germination were very necessary; (3) the seed coat had inhibitory effects on I. lactea, I. confusa and I. chrysographes, they all have physiological dormancy phenomena.7. Seed germination in four Iris species were carried out in this study. The results indicate that:(1) seed coat was the biggest resistance for seeds to germination in I. lactea, I. confusa and I. chrysographes. In I. tectorum endosperm was the biggest resistance for seed germination; (2) in I. tectorum seed coats had promoted effects on seed germination; (3)I. lactea and I. confusa adapted well to environment. The optimum substratum for I. tectorum seed germination was clay soils; (4) alternating temperatures 20/30℃were more suitable for I. lactea, I. confusa and I. chrysographes seeds germination; (5) 4℃stratification have no obvious effect for promote seed germination.更多还原