Effects Of Ultraviolet And Methyl Jasmonate On The Trichome Development Of Dendranthema Indicum Var.aromaticum And Dendranthema Indicum

Dendranthema indicum is an important medicinal and aromatic plant,and Dendranthema indicum var.aromaticum is a variety of Dendranthema indicum.The whole plant has strong fragrance,and it is also an aromatic plant with great medicinal development and garden application value.Plant trichome play an important role in plant defense,while non glandular trichome play a physical defense,which creates a physical barrier for herbivores,parasites and pathogens.Glandular trichome can synthesize and release a variety of chemicals,including flavonoids,terpenes,methyl ketones and surface proteins,and are the chemical factories of plants.Therefore,it is of ecological and economic significance to study the development process of the trichome of D.indicum var.aromaticum and D.indicum.In this paper,we observed the development process of the trichome of the D.indicum var.aromaticum and D.indicum,and used ultraviolet(UV-B)and methyl jasmonate(MeJA)to stress the plants of the D.indicum var.aromaticum and D.indicum.The effects of UV-B and MeJA on the area of meristem,the occurrence of trichome,the morphological structure of different developmental stages and the density of different developmental stages of the trichome were studied.In this paper,based on the transcriptome data obtained in the earlier stage,we analyzed the genes related to the surface coat of D.indicum var.aromaticum.The results show that:1.The area of primordial cells at the top of stem of D.indicum was larger than that of D.indicum var.aromaticum,and the binding degree at bud stage was smaller than that of D.indicum var.aromaticum and D.indicum both have two kinds of trichome:head glandular trichome and T-type non glandular trichome.Glandular trichome generally occur on stem D(the fourth leaf),and non glandular trichome generally occur on stem A(the first leaf).The glandular trichome of both D.indicum var.aromaticum and D.indicum are composed of two head cells.There are 2-3 basal cells and 1 T-type abnormal head cell in the non glandular trichome of the two species.There are 4-8 stem cells in D.indicum var.aromaticum and 2-8 stem cells in D.indicum.At different stages of leaf development,the glandular trichome on the surface of D.indicum var.aromaticum are more mature than those on the back of D.indicum.The density of trichomes on the leaves of D.indicum var.aromaticum and D.indicum was greater than that of the leaf surface,and the density of the coat decreased with the increase of the leaf surface area.There was no new trichome on the leaves of D.indicum var.aromaticum at the late growth stage.There are also new non glandular trichome and no new glandular trichome in the growth period of D.indicum leaves.2.UV-B treatment narrowed the area of primordial cells at the top of the stem of D.