Effects Of Different Scions On The Growth Of Camellia Oleifera Rootstock

Camellia oleifera is a unique woody oil tree species in China,with high economic value and use value.It is mainly distributed in southern China as an important pillar and advantageous industry of southern no-timble forest development.Camellia oleiflora trees can maintain the excellent characteristics of varieties,advance flowering and fruit,and improve yield and quality.Therefore,nurse seedling grafting g is the main means of propagation and utilization of Camellia oleiflora.At present,the research mainly focuses on the influence of rootstock on scion and the interaction mechanism.while the influence of the scion on rootstock has less influence.In this paper,the experiment was set up with three treatments.Treatment one was grafted seedlings with Camelli sp.as scion and Camellia oleiflora as rootstock.Treatment two was grafted seedlings with Camellia oleiflora as scion and rootstock.Treatment three was Camellia oleiflora seedlings without grafted,which were cut as the same as the grafted seedling.Through the analysis of the phenotypic traits of seedling,anatomical structure,photosynthetic characteristics,physiological and biochemical and transcriptome information of leaves rootstock,the effect of scion on rootstock was studied.Rootstock response mechanism to scion was established.The main research results are as follows:（1）Influence of different scions on grafted seedling growthBy analyzing the growth of grafted seedlings with different scion combinations,it was found that the scion had a great influence on the rootstock bud length,ground diameter of the grafted seedlings,but little influence on the growth of the branches.By studied on the root system of grafted seedlings,it showed that the scion promoted the growth of lateral roots of seedlings.The rootstock leaf area,length and width with Camellia oleiflora as scion are the highest,indicated that the rootstock leaves with Camellia oleiflora as scion.（2）Influence of different scions on anatomical features of rootstock leaves and rootsIn root anatomy,it was found that the roots of the grafted seedlings were better developed at the early stage,and the grafted seedling with Camellia oleiflora as scion grew best.In rootstock leaves anatomy,there were significantly different of the ratio of palisade tissue to leaf thickness（DCTR）and palisade tissue to sponge tissue（TRPS）among the three treatments,which indicated that different scions had different the effect on leaf cell structuret,and rootstock leaves with Camellia oleiflora as scion had significantly greater than the other two treatments.（3）Influence of different scions on photosynthetic characteristics of rootstock leavesStudies on photosynthetic characteristics of rootstock leaves,there were significant differences in photosynthetic characteristics with three treatments,and the indicators of photosynthetic characteristics were best in the grafted seedling with Camellia oleiflora as scion,which indicated that rootstock leaves with Camellia oleiflora as scion had stronger photosynthetic capacity.The correlation analysis of leaf photosynthetic indicators showed that the Pn of leaves had high significant positive correlation with Tr and GS.Tr and GS were extremely significantly positively correlated.Tr and GS were both significantly negatively correlated with chlorophyll a/b.Chlorophyll indicators,chlorophyll a,chlorophyll b,total chlorophyll and carotenoids in rootstock leaves showed an extremely significant positive correlation.To simulate the photosynthetic response of rootstock leaves and CO₂response data,it was found that rootstock leaves with Camellia oleiflora as scion had high utilization of weak light,the most wide of using the light intensity,the highest utilization rate of CO₂ concentration.But in the leaves of the control group,photosynthetic electron transport rate and photosynthetic phosphorylation activity was better than the other two combinations.（4）Influence of different scions on physiological characteristics of rootstockBy comparing the three treatments,the rootstock leaves of the control treatment had highest MDA content,CAT and POD enzyme activity,followed by rootstock leaves with Camellia sp.as scion,and with Camellia oleiflora as scion.The results showed that the stress was the largest in the control,followed by grafted seedling with Camellia sp.as scion,and with Camellia oleiflora as scion.The rootstock leaves of the control treatment had highest PPO enzyme activity and SS content,followed by rootstock leaves with Camellia oleiflora as scion,and with Camellia sp.as scion.The results showed that the physiological activity was the largest in the control,followed by grafted seedling with Camellia oleiflora as scion,and with Camellia sp.as scion.In the correlation analysis,it was found that there was significant positive correlation between MDA content and POD enzyme activity in rootstock leaves,and significant positive correlation between PPO and CAT enzyme activity and chlorophyll.（5）Analysis of transcriptome differences in rootstocks leaves under different treatmentBy high-throughput sequencing,781 752 transcripts and 497 972unigenes were found.GO analysis showed that 1 286 differentially expressed genes were reached by compared with three treatments.KEGG analysis showed that there was significant enrichment in phenylpropane biosynthetic pathways in three treatments.Through correlation analysis,the morphological,photosynthetic,physiological and biochemical indeses of rootstock leaves were significantly correlated with the corresponding transcriptional data.In addition,RT-q PCR verification of common differentially expressed genes in rootstock leaves showed that the fluorescence quantitative relative expression was significantly positively correlated with FPKM in the transcriptome expression.