Effects Of Tiller Propagation And Graft Propagation On Growth,Leaf Traits And Root Growth Of ’Lingwuchangzao’

’Lingwuchangzao’ is an excellent jujube variety in Ningxia.It has the characteristics of drought resistance,salt tolerance and so on.Its fresh fruit flesh is delicious,juicy and nutritious,which is loved by consumers.The main breeding mode of ’Lingwuchangzao’ is the same as other jujube trees,and grafting and root tillering are the main breeding methods.In this study,5-year-old ’Lingwuchangzao’tillers and grafted plants were used as experimental materials to determine the effects of two breeding methods on the nutrient growth of ’Lingwuchangzao’.By studying the changes of nitrogen,phosphorus,potassium,photosynthetic characteristics and chlorophyll fluorescence indexes in leaves,the differences of nutrient absorption and photosynthetic product accumulation under the two breeding methods were clarified.The root length,root average diameter,root tip number,surface area and volume were observed,and the effects of two breeding methods on the root growth of ’Lingwuchangzao’ were analyzed.Lay the foundation for related research.The results show that:(1)Grafting propagation of ’Lingwuchangzao’ was 5-9 days earlier than that of ’Lingwuchangzao’in germination stage,leaf expansion stage and flowering stage,and 4 days later in deciduous stage.The growth of hanging and spring shoots of grafted ’Lingwuchangzao’ was significantly higher than that of root tiller ’Lingwuchangzao’,and the net growth of tree height,ground diameter and crown width increased by 9.76%,46.92%and 14.30%,respectively.Moreover,the total number of branches and middle-long branches grafted with ’Lingwuchangzao’ were more.The number of internodes of’Lingwuchangzao’ was large and the internode spacing was short.The leaf area growth of grafted’Lingwuchangzao’ was significantly higher than that of grafted ’Lingwuchangzao’,and the total leaf area growth was 35.36%higher than that of root tiller ’Lingwuchangzao’.In the late growth stage,the leaf shape index and chlorophyll of root tiller ’Lingwuchangzao’ were significantly higher than those of grafted ’Lingwuchangzao’,which were 8.55%and 14.91%higher than those of grafted’Lingwuchangzao’,respectively.(2)The contents of total nitrogen and total phosphorus in leaves were maintained at 2.33%-2.85%and 0.29%-0.68%,respectively,showing a downward trend throughout the whole growth period.The total potassium content in leaves remained at 1.89%-2.39%,and fluctuated greatly throughout the whole growth period.It showed an upward trend from mid-June to mid-August,and a downward trend after mid-August.Leaf organic carbon content showed a ’W’-shaped change,reaching a valley in mid-July and late September.Leaf C/N ratio and N/P ratio showed an upward trend in the whole growth stage.During the whole growth stage,the total potassium and organic carbon content,C/N ratio and N/P ratio of root tiller ’Lingwuchangzao’ leaves were significantly higher than those of grafted’Lingwuchangzao’ leaves,while the total nitrogen and total phosphorus contents were significantly lower than those of grafted ’Lingwuchangzao ’ leaves.(3)The transpiration rate,stomatal conductance and net photosynthetic rate of ’Lingwuchangzao’were significantly higher than those of ’Lingwuchangzao’,but there were no significant differences in intercellular CO2 concentration and water use efficiency.The initial fluorescence(F0)of’Lingwuchangzao’ was lower than that of ’Lingwuchangzao’,but the maximum fluorescence(Fm)was higher than that of ’Lingwuchangzao’.The maximum light energy conversion efficiency(Fv/Fm),relative transfer rate(ETR)and photosynthetic quantum yield(YII)of ’Lingwuchangzao’ were higher than those of ’Lingwuchangzao’.(4)Compared with ’Lingwuchangzao’,the new root length,root surface area and root volume of grafted ’Lingwuchangzao’ were significantly higher,the root system was thicker and the number of root tips was more.Root tillers and grafting propagation ’Lingwuchangzao’ had the largest proportion of new roots at d≤1.0 mm diameter level,and the new root length and root tip number of grafting’Lingwuchangzao’ at 1.0<d≤2.0 mm and d≥2.0 mm diameter levels were significantly higher than those of root tillers ’Lingwuchangzao’.In summary,the new roots of grafted ’Lingwuchangzao’ grew well,provided sufficient nutrients for plants,formed good tree vigor,and provided the basis for the yield increase of ’Lingwuchangzao’.Root tillering ’Lingwuchangzao’ has good photosynthetic characteristics,which provides a good condition for the formation of fruit quality in subsequent growth.