Study On Biological Characteristics Of Empetrum Nigrum Var.japonicum

This thesis focuses on the study of Empetrum nigrum var.japonicum,which grows in the rocky mountains of the Greater Khingan Mountains.It explores its phenological characteristics,changes in leaf pigment content with natural cooling and warming,anatomical structure of vegetative organs,branching and growth characteristics,and other biological characteristics,providing reference for the cultivation and protection of this species resource.The main research findings are as follows:(1)Empetrum nigrum var.japonicum is an evergreen plant that can sprout,bloom(fruit),and expand its leaves(change color)twice a year.The budding time of flower buds is mid to late April and mid to late August;The germination time of terminal leaf buds is from late April to early May and late August;The germination time of axillary leaf buds is from early to mid May and from late August to early September.The flowering period is mainly from late April to early May,with a small amount of flowers blooming from late August to mid September.After flowering will bear fruit,and from late June to early August,the fruit will change from green to purple red to black.After flowering in September,the fruit will occasionally be seen.The leaf expansion period is from mid to late May and early to mid September.From early September to late October of that year,the leaves gradually changed from green to reddish brown during the growing season and were buried by snow to survive the harsh winter.The temperature rose from early May to late May of the following year,and after the snow melted,they gradually returned to green.The essence of this change process is mainly the result of alternating changes in anthocyanin and chlorophyll content,which is one of the self-protection mechanisms in response to severe cold.(2)The leaves curl inward,and the palisade tissue is arranged more closely than the sponge tissue,but the thickness is small;Compared with the normal growth period,the thickness,palisade tissue and sponge tissue ratio,cell structure compactness and cell structure porosity of palisade tissue and sponge tissue entering the snow cover period were not significantly different,but the thickness of the upper epidermis and leaves significantly thinned,while the thickness of the lower epidermis and corneum increases;The thickness of leaves during normal growth period and entering snow cover period is 142.35μm167.60μm.The significant thinning of leaf thickness during the snow cover period is mainly caused by the thinning of the upper epidermis.During normal growth,the cork layer in the peridermis of the stem is 44.93μm.The xylem in vascular tissue is relatively developed,246.31μm.The thickness of cork layer,cork cambium,cork inner layer,xylem and phloem of the stem is significantly thinner,and the pith radius and stem radius are significantly reduced from the normal growth period to the snow period.The cells in the root are arranged tightly,and the epidermal cells differentiate to form root hairs.The structure of each component of Empetrum nigrum var.japonicum has a certain degree of plasticity to protect it from normal winter weather.(3)The uncertainty of apical dominance of terminal buds is variable,that is,both terminal buds and proximal axillary buds have "apical dominance",and both germinate to form "one excellent and multiple strong apical dominance" or only the latter germinate to form "multiple strong apical dominance";The apical dominance of terminal bud is very strong,which inhibits axillary bud germination and reduces the number of lateral branches to adapt to the changing growth environment and expand living space.There are 5 types of branch sprouting and branching,among which there are many types of extended branch clusters and no-extended branch clusters,with high branching rates of 4.80 and 6.75.The branching rates of no side branch extension branches,no near branch top side branch extension branches,and non-near branch top side branches are low,with an average branching rate of 3.47.The annual growth of branches is relatively small,with an average length of 1.93 cm and an average diameter of 0.55 mm.The branches are relatively slender.The branches at or above 3 year old are creeping and grow adventitious root gradually to adapt to the extremely changeable living environment and ensure the growth and reproduction of the population in the environment.