The Effect Of Nitrogen Concentration On Bolting And Flowering Of Flowering Chinese Cabbage

The flowering is a sign of the transformation from vegetative growth to reproductive growth in plant.Nitrogen is one of the most important nutrients for plant growth and yield.Nitrogen also affects the flowering of plants,and the lack of nitrogen causes the plants to flowering in advance,and too much nitrogen can delay the flowering.flowering Chinese cabbage(Brassica campestris L.ssp.chinesis var.utilis Tsenet Lee.)is an important vegetable with a stem,and it is necessary to the develop of plant organ.So far,it is still not clear that the flowering mechanism of flowering Chinese cabbage,especially the study on the mechanism of nutrition regulation is less.Therefore,it is of great theoretical significance to study the growth and development of nitrogen nutrition and the mechanism of bolting and flowering of flowering Chinese cabbage.This study under hydroponic conditions,use a series of low nitrogen,normal nitrogen and high nitrogen level as treatment,the research on the growth and development of vegetables,bolting and flowering time,plant nutrition status,content of endogenous hormone,expression of flowering related gene,the influence of the stem cell structure,probe into the internal relation of nitrogen concentration and take out moss green tender.The main results are as follows:1.The concentration of different nitrogen levels significantly affected the growth and development,and the flowering of flowering Chinese cabbage.Compared with the normal nitrogen supply,the low nitrogen treatment made the buds and flowering time earlier,and the lower the concentration of nitrogen,the earlier the flowering of the vegetable.The low nitrogen treatment reduced the plant height,stem thickness,leaf number,leaf area and biomass,but improved the root ratio of the plant.2.Nitrogen concentration significantly affected the nutritional status of vegetable plants.Compared with the normal for nitrogen,low nitrogen treatment reduced the vegetables planting of total nitrogen,total phosphorus,total potassium content,and increase nitrate,soluble protein and free amino acid content in organs,improve the total carbon content and C/N ratio.The C/N ratio was significantly positively correlated with plant height,stem diameter and biomass,and was negatively correlated with flowering rate.This shows that nitrogen nutrition affects the bolting and flowering of flowering Chinese cabbage by regulating the C/N ratio of the plant.3.The interaction between nitrogen and endogenous hormones regulates the flowering of flowering Chinese cabbage.Under the condition of low nitrogen,vegetables leaf and stem tip of GA,IAA,CTK,BR content increased after the treatment in 10 ~ 15 d,and take out moss green tender flower related gene SOC1-1,SOC1-2,the expression of LFY quantity increases after the treatment in 15 ~ 20 d.It is suggested that nitrogen can influence the flowering of flowering Chinese cabbage by regulating endogenous hormone content of GA,IAA,CTK and BR and the expression of flowering gene.4.Nitrogen nutrient levels affect the growth of flowering Chinese cabbage.In the low nitrogen condition,the cell area of stem was decreased,the cortex parenchyma cells showed a short column,and the number of cell layers increased,resulting in a significant decrease of the r stalk.Under low nitrogen treatment,the expression of CYCD3-3,CYCB1-1,and cell wall relaxation factor EXPA8 was down-regulated in the stem point.It is suggested that nitrogen can regulate the development of the stem by regulating the expression of genes related to cell structure.To sum up,nitrogen nutrition regulates growth development and flowering by changing plant nutrition status,endogenous hormone content and related gene expression.Under the low nitrogen level,the plant were grown by increasing the C/N ratio of the plants,and the flowering of the plant was early.By down-regulating the expression of related genes in the cell structure,negative to regulate the development of plant stem;The flowering rate was increased by increasing endogenous hormone content and flowering gene expression.