Effects Of Different Carbon Sources On Domestication And Transplanting Of ’Pinot Noir’ Plantlets

Grapevine（V.vinifera L.）plantlets are mainly propagated by asexual propagation methods such as cutting,grafting,etc.However,the saplings growth cycle is longer and the quality of saplings is uneven.Therefore,it is especially significant to obtain virus-free plants through tissue culture and then conduct domestication and transplanting.Nevertheless,the special growth environment of the plantlets results in a lower photosynthetic capacity and slower physiological metabolism,which leads to the difficulty of domestication and transplanting of test tube saplings.In this experiment,four culture conditions,namely,medium with sucrose（S1）,medium with sucrose and simultaneously applying high concentration of CO₂（CS）,medium without sucrose but with high concentration of CO₂（C0）,and medium without sucrose（S0）,were set to respectively culture pinot noir plantlets.The relationship between the synthesis of lignin and photosynthesis and the transport of photosynthetic products was studied.In order to provide a theoretical basis for in vitro saplings transplantation.The main results are as follows:1.For the plantlets treated with CO₂,their transplant survival rate was higher and the root system was well developed after domestication and transplanting.Moreover,the anatomical structure of the leaves was more developed on the 35th day after transplanting.Finally,the principal component analysis showed that the plantlets of CS treatment had stronger photosynthesis ability during domestication and transplanting.2.During the growth of plantlets,the spalings treated with CS and C0 grew robustly and had strong photosynthetic ability.When the plantlets were grown to the25th day,the soluble sugar,starch and sucrose content were higher in the leaves of CS treatment.However,the accumulation of photosynthetic products was more in the leaves of S1 treatment on the 35th day.At the same time,the results of qRT-PCR indicated that the relative expression levels of each gene associated with photosynthesis in CS-treated leaves were up-regulated compared to other treatments,which were finished using the the leaves of various stages of plantlets.3.In the early stage,our team members conducted the analysis to the transcriptome data that was from leaves of plantlets treated with different carbon on the 25th day.By digging into transcriptome data,we found that phenylpropanoid biosynthesis pathway was significantly different,including 30 related differentially expressed genes.The qRT-PCR verification of differentially expressed genes showed that the relative expression of CAD in CS treated leaves was 67%lower than that in S1 treated leaves,and the difference was significant.4.During the growth of plantlets,the content of soluble sugar,starch and sucrose was higher in the stem of plantlets treated with CS,the breaking resistance of the stem was the highest,and the accumulation of lignin was the highest.The qRT-PCR of the differentially expressed genes related to lignin synthesis in the stems of 25d and 35d spalings showed that the relative expression of CAD,PAL and other genes in CS treated stems was significantly higher than that of S1 when growing to the 35th day.