Effects Of Olive Rootstock ’Tianyuan 1’ On Morphological And Physiological Characters Of Leaves And Fruits Of ’Arbosana’ Grafted Tree

Native to the Mediterranean region,olive(Olea europaea L.)is the world-famous woody oil and fruit tree,and has been introduced and cultivated in more than 40 countries worldwide.Virgin olive oil,cold-pressed from fresh fruits,is a natural,high-quality edible vegetable oil.As its rich antioxidant and high content of unsaturated fatty acid,olive oil provides the function of nutrition.The history of olive introducing cultivation in our country lasted more than 50years,with a planting area of over 167 000 hm~2,especially in Gansu,Yunnan and Sichuan Province.However,the growth and development of olive is affected by the difference of soil and climate environment between China and the Mediterranean region.Therefore,the research on cultivation techniques and varieties breeding based on the environmental characteristics of the introduced areas can improve the yield and quality of olive,which makes practical significance for the further development of olive industry.Previous studies have found that O.cuspidata Wall.,a wild related species of olive,and its hybrid progenies with olive have excellent stress-resistance,disease-resistance and adaptability to acid red soil,and their fruits also exhibit excellent characteristics,which can be used as an excellent rootstock genetic resource.At the early stage,we found that the height,ground diameter and crown diameter of‘Arbosana’that grafted onto rootstock‘Tianyuan 1’increased by 38%,36%and 78%respectively,and the yield increased by 4.5 times in the olive orchard in Lijiang,Yunnan Province.Given this,we plan to utilize this grafted combination to build a large-scale olive orchard.Therefore,to investigate the effects of rootstock‘Tianyuan 1’on the morphological and physiological characters of leaves and fruits in‘Arbosana’,the trees of‘Tianyuan 1’,‘Arbosana’,and their grafted trees‘Tianyuan 1’/‘Arbosana’were used for the measurement.The indicators included leaf and fruit morphology,leaf anatomical structure,photosynthetic pigments content,nutrient elements content,and fruit fatty acid content.And then the difference comparison between‘Arbosana’and grafted trees‘Tianyuan 1’/‘Arbosana’was analyzed,the correlation analysis of physiological indicators was conducted.It is hope that it can reveal the rootstock characteristics and cultivation value of‘Tianyuan 1’,and provide a theoretical basis for the application and promotion as well as the high yield cultivation of the grafted combination‘Tianyuan 1’/‘Arbosana’.The main results are as follows:(1)Compared with the ungrafted trees of‘Arbosana’,its grafted trees‘Tianyuan1’/‘Arbosana’had no significant difference in phenotypic qualitative traits(shape,symmetry,and so on)of leaf and fruit,so did the fruit ripening index.And there is also no significant difference in leaf phenotypic quantitative traits(leaf length,leaf width,leaf area,and leaf perimeter)and flesh content.Phenotypic quantitative traits of fruit and stone were decreased significantly,including weight,length,and width in fruit and stone,they decreased by 6%,3%,11%,3%,3%and 13%respectively.And there were also significant difference in leaf anatomical structure,mainly reflected in the thickness of blade and palisade tissue decreased significantly,they decreased by 7%and 15%respectively.(2)Compared with the ungrafted trees of‘Arbosana’,its grafted trees increased the chlorophyll content in the leaves,the contents of total chlorophyll(Chlt)and chlorophyll a(Chla)increased by 14%and 13%respectively,and the ability to absorb bright light increased.The contents of nutrient elements in leaves also changed.In grafted trees,including nitrogen(N),calcium(Ca),magnesium(Mg),and manganese(Mn)increased by 7%,69%,23%and45%,while potassium(K)and zinc(Zn)content decreased by 12%and 23%,they all exhibited significant significance;however,there was no variation in boron(B)deficiency in leaves.(3)There were significant differences in fatty acids between two harvest times in grafted and ungrafted trees of‘Arbosana’.Compared with the fruits harvested in the late August,the contents of palmitoleic acid(C16:1),linoleic acid(C18:2),polyunsaturated fatty acid(PUFA)in fruits harvested in the late September increased,they increased by 33%,51%and 40%in‘Arbosana’,while they increased by 35%,44%and 34%in grafted tree;the contents of oleic acid(C18:1),arachic acid(C20:0),monounsaturated fatty acid(MUFA)and MUFA/PUFA decreased by 5%,12%,4%and 31%in‘Arbosana’,while they increased by 5%,11%,4%and29%in grafted tree.All the indicators mentioned above exhibited significant difference between grafted and ungrafted trees of‘Arbosana’.In fruits of‘Arbosana’and its grafted trees,there was no significant difference in 12 fatty acids contents,and it’s the same with saturated fatty acid(SFA),unsaturated fatty acid(UFA),MUFA,PUFA,and their ratio(UFA/SFA and MUFA/PUFA).(4)Moreover,there was a positive correlation between chlorophyll content and the nutrient elements contents(N and Ca)in leaves,the correlation coefficient were 0.68 and 0.58respectively.The correlation between the main fatty acids in fruits and the contents of photosynthetic pigments and nutrient elements in leaves was not significant.And there were strong correlation among the fatty acids,so were nutrient elements.In conclusion,rootstock‘Tianyuan 1’grafted with‘Arbosana’promoted the growth and development of grafted trees,increased the chlorophyll content and the contents of nutrient elements(N,Ca,Mg,and Mn)in leaves.There was no significant effect on the morphology of leaves and fruits,and there were no negative effect on the content of B and fatty acids,and fruit maturity.Moreover,based on the field investigation,rootstock‘Tianyuan 1’grafted with‘Arbosana’exhibited graft compatibility in terms of phenotypic traits,physiological characteristics,yield performance and growth characteristics,which demonstrated applicability and feasibility of this rootstock/scion combination in the production,which provided a scientific basis for the application and popularization of excellent grafted combination as well as high yield and high quality cultivation,and it is of great significance to improve the quality and efficiency of olive industry in China.