Research On Non-glandular Hair Development In Epimedium L. And Characteristics In Epimedium Davidii Franch. Complex

Objective: Epimedium L.(Berberidaceae)is the largest genus of herbage types,which has been a difficult group in taxonomy.Among the morphological features used for classification,the non-glandular hairs on the abaxial surface of leaves have rich diversity and characteristics,and the identification of Epimedium leaves depends on the morphology of non-glandular hairs.Based on the morphological observation of non-glandular hairs in Epimedium L.,the structural characteristics of non-glandular trichomes were summarized.This paper deals with the application of morphological differentiation of non-glandular hairs in the taxonomy and evolution of Epimedium.E.davidii complex is the primitive type of Epimedium L.in China,and is also the most abundant group of non-glandular hairs.In this paper,the relationships among species in a complex population are discussed according to the types and distribution of non-glandular trichomes.Methods: In this paper,we selected E.davidii complex and E.pubescens complex,which can cover the main non-glandular hair types in genus,to observe the non-glandular hair development.The former contains 12 species and 31 populations,the latter includes 4 species and 32 populations.Firstly,according to the importance and sequence of cell development,non-glandular hairs were divided into 4 types:(1)1 cell non-glandular hairs;(2)2～4 cells non-glandular hairs;(3)5～10 cells non-glandular hairs;(4)10+ cells non-glandular hairs.Among them,(2)and(3)categories also include a variety of morphological types.Four leaves of different developmental stages were selected for each population,namely,Leaf Buds,young leaves,growing leaves and mature leaves.The surface slices were prepared and observed by optical microscope.The observed contents were divided into cell division,elongation,thickening of cell wall,Intercellular connection becomes right angle,and development time of non-glandular hairs on the back of leaf,etc.And observe the morphology of the adult leaf non-glandular hair of each population of the E.davidii complex.Results: According to the observation results,the order of the non-glandular hair cells of Epimedium is: The cells divide first,then elongate(some of them have longer apical cells,i.e.dividing while elongating),at the same time of elongating,some non-glandular hair cells joined at a certain angle,right angle.The division development of non-glandular hairs of Epimedium is divided into two stages.The first stage is before the 3-cell stage,three kinds of multi-cell non-glandular hairs such as 2～4 cell non-glandular hairs,5～10 cell non-glandular hairs and more than 10 cell non-glandular hairs are identical,that is,all cells have the ability to dividing.This mode is different from that of other plant that only the apical and intermediate cells have the ability to divide,and the basal cells do not divide.The second stage is 4-cell division and afterwards,and the second stage is followed by 5～10 cells non-glandular hairs and more than 10 cells non-glandular hairs.The former is that only the apical cells and the adjacent cells below the apical cells are capable of division,the more the number of cells was,the fewer the number of cells retained the ability to divide,and finally only the apical cells had the ability to divide.While the basal cells of more than 10 cells non-glandular hairs showed the ability to divide.According to the characteristics of cell division,the non-glandular hairs of Epimedium L.can be divided into three types: multicellular hairs,which basal cells maintain the ability to divide for a long time and develop earlier on the abaxial surface of leaves,undifferentiated non-glandular hairs which developing time is longer on the abaxial surface of leaves;non-glandular hairs which apical cell is longer,mostly later developed on abaxial leaf surface.In this paper,the morphology and cell number of non-glandular hairs of different populations of E.davidii complex were studied,the types of non-glandular hairs were classified as follows: A: Straight hairs(classified as A1～A5),B: undifferentiated non-glandular hairs(classified as B1 ～ B4),C: appressed hairs(classified as C1～C2)and Multicellular hairs D.Based on the composition and division of non-glandular hairs in different populations,the evolution of non-glandular hairs in E.davidii complex was analyzed as follows: Straight hairs →undifferentiated non-glandular hairs,straight hairs → appressed hairs.Among the straight hairs: A4(→ A3)→ A2(→ A5)→ A1;among the undifferentiated non-glandular hairs: B3(→ B4)→ B1→ B2;among the appressed hairs: C1→ C2;The relationship among species in E.davidii complex group discussed according to the characters of non-glandular hairs and flowers.Conclusion: According to the observation and research on the development of non-glandular hair of Epimedium L.and the non-glandular hair of E.davidii complex,the conclusions of the study are summarized as follows: 1.It was found that the sequence of non-glandular hair cells in Epimedium is as follows: the cells divide first,then elongate,and at the same time,some non-glandular hair cells are connected at right angles or obtuse angles.2.The division and development of non-glandular hair of Epimedium(1)Before the division at the 4-cell stage,all cells have the ability to divide.(2)There are two types after the 4-cell division,and the development time of different types of non-glandular hairs on the leaves,which is helpful for the classification and evolution analysis of non-glandular hairs in Epimedium.3.According to the morphology and cell number of non-glandular hairs of each population of the E.davidii complex,summarize the types of each non-glandular hair.And,based on the classification of non-glandular hair morphology,and the non-glandular hairs of each population Composition,analysis and analysis of the evolutionary relationship of non-glandular hairs in the E.davidii complex.4.According to the characteristics of non-glandular hairs and the flowers of each population Composition,the relationship between the species in the E.davidii complex was discussed,and the type composition of non-glandular hairs was found to be helpful for inference of hybrid species.