Study On Southwest Sichuan Fagopyrum Cymosum Population Morphological Differences And Different Habitats Impact

Fagopyrum cymosum(Trev.)Meisn.was a perennial herb of the genus Fagopyrum,which was the national second-class protected plant with high medicinal and nutritional value.It has been found that the Fagopyrum cymosum(Trev.)Meisn.population in the same habitat or in different habitats will have large morphological differences.Such differences and changes have long been a hot topic of debate for scholars all over the world about the traits and taxonomic status of the species.The Fagopyrum cymosum(Trev.)Meisn.was collected from three different habitats of Sichuan Plain(Wenjiang and Jinjiang),Ya’an and Hengduan Mountain(Longzhou Mountain and Luoji Mountain).The investigation of the Fagopyrum cymosum(Trev.)Meisn.vertical distribution and population density changes,the analysis of the morphological changes,the correlation between the morphological and habitat factors,and the phylogenetic tree of two molecular markers ITS and matK were established to study the morphological characteristics of Fagopyrum cymosum(Trev.)Meisn under different habitats.The similarities and differences between the molecular markers and the molecular markers,then raise the theoretical basis of the population relationship and classification of Fagopyrum cymosum(Trev.)Meisn.The main results are as follows:1.The differences in the appearance and ecological environment of Fagopyrum cymosum(Trev.)Meisn: genetic stability and environmental impact on morphological characteristics.The reproductive organs of plants have relative genetic stability and are less affected by external habitat conditions than vegetative organs.Therefore,the morphological characteristics of the reproductive organs of plants,such as flowers and fruits,should be studied first in plant taxonomy.The morphological characteristics of the Fagopyrum cymosum(Trev.)Meisn.population in the three different habitats of Sichuan Plain(Wenjiang and Jinjiang),Ya’an and two typical areas in Hengduan Mountain(Longzhou mountain and Luoji mountain)were found: the morphological characteristics of the vegetative organs of the Fagopyrum cymosum(Trev.)Meisn.population were quite different.With the elevation increases,the specific manifestations were the decrements of length and width of the leaf,the leaf shape changed from ovoid,triangles gradually to triangles and pods,leaves become thicker,plant heights become shorter,stems gradually become thinner from Chengdu Plain to Ya’an to Luoji mountain and Longzhou mountain.In addition,the fertility of Fagopyrum cymosum(Trev.)Meisn.also showed significant changes in these three types of areas,Fagopyrum cymosum(Trev.)Meisn.could complete flowering and fruiting in the two regins in Hengduan Mountain and Ya’an;and the Wenjiang and Jinjiang District of the Chengdu plain,Fagopyrum cymosum(Trev.)Meisn.could only be flower and could not be fruiting.It might be closely related to the habitat factors such as the low-altitude(560m),high-humidity(80%),and small diurnal temperature difference in the West Sichuan plain.At the same time,the flower organs of Fagopyrum cymosum(Trev.)Meisn.in the three special habitats showed two types: stamen(anther)longer than pistil(style)and stamen(anther)shorter than pistil(style).Fagopyrum cymosum(Trev.)Meisn.as the large grain group of wild buckwheat,the seeds produced by the two kinds of flower organs were different.The main manifestations were that the long pistil-shaped flowers mainly produced sharp triangular pyramidal seeds,while the short pistil-shaped flowers produced mainly blunt triangular pyramidal seeds.This showed that the seed and flower reproductive organs had relatively high genetic stability.2.According to the correlation analysis of the morphological characteristics and habitat factors of the quinoa vegetative organs,it was found that height significantly negatively correlated with the altitude(-0.363**),while a significant positive correlation with the frost-free period(0.240*),and a very significant positive correlation with the annual mean temperature(0.437**).The leaf length and the annual sunshine hours(-0.264*)presented a significant negative correlation,and a highly significant negative correlation with altitude(-0.303**),annual average temperature(-0.351**),while a highly very significant positive correlation with the annual average precipitation(0.384**).In addition,there was a significant negative correlation between leaf width and altitude(-0.067*)and annual sunshine hours(-0.097*),while other correlations were not significant.(* indicates α=0.05,** indicates α=0.01.)This showed that the differences in morphological characteristics of the vegetative organs of the Fagopyrum cymosum(Trev.)Meisn.were obviously related to the differences in habitat factors.3.Based on two molecular markers of ITS and matK,the phylogenetic tree analysis of Fagopyrum cymosum(Trev.)Meisn.with different habitats in three regions showed that the individual plants of Fagopyrum cymosum(Trev.)Meisn.population in different habitats,stamens longer than pistils were divided into one category,stamens shorter than pistils were divided into another category.It was showed that two different types of Fagopyrum cymosum(Trev.)Meisn.had been evolved and significant differences have occurred at the molecular level under the long-term natural selection.However,it still requires further support of molecular biology or subspecies reproductive biology,cell biology evidence,whether this difference reaches the level of varieties.