The Effects Of Pruning On The Carbon Nitrogen Metabolism And The Source-sink Relationship Of Plumbago Auriculata

Plumbago auriculata is a new kind of garden application material that combines ornamental and medicinal values.Since the introduction from African cultivation in China in Sichuan,it was observed that the branches of the year have flowers,long flowering period,resistance to pruning,and strong sprouting ability.Pruning in dormant season is an important method to adjust the nutrient distribution of Plumbago auriculata.It will change the carbon and nitrogen nutrient distribution of the plant,because carbon and nitrogen nutrition plays a key role in plant nutrition and reproductive growth.Then,what are the different levels of pruning on their growth,nutrient distribution,and source-stock relationship? In order to answer the questions above,this study used five-year-old Plumbago auriculata as the test material to design four different strengths of pruning methods(not cutting back,cutting back 1/5,cutting back 2/5,cutting back 3/5).In combination with the field random sampling statistical technique,the physiological metabolic differences in different growth periods of Plumbago auriculata were compared,and the different pruning intensities of carbon,nitrogen nutrient accumulation,carbon and nitrogen metabolism-related enzyme activities in leaves and flowers were analyzed.The effects of C/N and biomass on the pruning regulation of the dormant season during the dormant season have provided a theoretical and technical approach for the establishment of the science of flower buds.The results showed that:1.Experiments were conducted to study the effect of different cutting back intensity treatments on shoot growth index and leaf traits.The results showed that the cutting back 1/5 treatment increased the percentage of new shoots in the flower bud by 18%;the length and diameter of shoots were comparable to those of the control.The pruning intensity was positively correlated;the short cuts of medium(2/5)and high(3/5)increased plant specific leaf area by 56% and 55%,respectively;light(1/5),medium(2/5)Intensity of cutting back treatment promoted the chlorophyll content in the leaves of plants by 19% and 18%,respectively.2.Cutting back treatment can promote the accumulation of carbon nutrition and the increase of carbon metabolic enzyme activity in leaves.Light and cutting back(1/5)treatment can promote the increase of soluble sugar,starch and sucrose in the leaves and flowers of the plant at the early flowering stage.At the time of treatment,the leaf SPS was increased by 27% compared to the control,and the SS activity in the treated flower was increased by 29% compared to the control.This effect decreased with the increase of the pruning force.The medium(2/5)and heavy(2/5)cutting back can promote the accumulation of carbon nutrition and the increase of SPS activity in leaves of late flowering stage.3.The short dormancy period had a significant effect on the accumulation of soluble protein and nitrogen and the activities of GS and NR during the vegetative growth period.During the vegetative growth period,the promoting effect increased with the increase of cutting back intensity.There was no significant difference in leaf soluble protein content between treatments during the reproductive-growth phase;whereas,from the vegetative phase to the late flowering phase,the GS and NR activities in the high(3/5)intensity cutting back leaves increased by an average of 27% and 10%.4.Different cutting back treatments have obvious effects on the regulation of carbon metabolism in leaves.Different treatments of Plumbago auriculata showed a trend of first increase and then decrease in C/N.C/N ratios were from high to low respectively.Yes: Short 1/5> CK> Short 2/5> Short 3/5,combined with the above conclusion,light and short cut(1/5)treatment can promote the plant to achieve a high level of carbon and nitrogen metabolism balance.5.Cutting back treatments have different effects on the regulation of the source and sink relationships of Plumbago auriculata.Light cutting back(1/5)treatment can promote nitrogen nutrition accumulation,C/N ratio and flower quantity,dry weight of flowers,the amount of flowers and dry weight per unit leaf area during the flowering process of Plumbago auriculata;Cutting back can promote the increase of leaf area and stem elongation.From the point of view of source and sink,light and cutting back in dormant season can promote the plant’s strong source and pool,and achieve a high level of source and bank balance.