Study On Response To Phosphorus Of Morphology And Physiology Of Different Stock-scion Combinations Of Camellia Oleifera In Seedlings

Bud-seedling rootstock grafting is the main way to breed Camellia oleifera Abel.The growth of grafts is closely related to their nutrient utilization ability.Phosphorus is a nutrient factor that is generally lacking in the main producing areas of Camellia oleifera.It is important to study the different response to phosphorus of different Rootstock-scion combination seedlings for guiding the selection of rootstock and scion in Camellia oleifera grafting.In this study,Ganwu 2 was used as rootstock or scion and grafted with Ganshi 83-1 and Ganwu 8 to form five different rootstock combinations:Ganwu 2/Ganwu 2,Ganwu2/Gan 8,Ganwu 2/Ganshi 83-1,Gan 8/Ganwu 2,Ganshi 83-1/Ganwu 2.The rootstock combinations were cultured under different phosphorus nutrient conditions(0,0.50mmol.L^-1).The different response to phosphorus of different Rootstock-scion combination seedlings at seedling stage of Camellia oleifera were studied from morphological and physiological aspects by measuring growth index,photosynthetic index and nutrient distribution.The main conclusions are as follows:1.The morphological index,physiological and biochemical indicators such as chlorophyll in July,photosynthetic characteristics in August-September,POD,SOD,CAT and ACP activities of leaves were significantly different.The different were reflected by rootstocks and scion varieties together.The Pmax and LSP,N,P and K uptake and utilization efficiency of different Rootstock-scion combinations were significantly different,and this difference was mainly reflected in scion varieties.2.At the same phosphorus level,the growth of seedling height and diameter,number of branches,leaf shape parameters and dry matter accumulation of combination Gan8/Ganwu 2 was better than those of other combinations;the total root length,total root surface area and total root volume of combination Ganshi 83-1/Ganwu 2 and Gan 8/Ganwu2 were higher than the others.The chlorophyll content of combination Ganshi 83-1/Ganwu2 and Gan 8/Ganwu 2 were higher,and the photosynthetic characteristics of combination Ganshi 83-1/Ganwu 2 were better,and the Pmax and LSP of combination Ganshi 83-1/Ganwu 2 were higher than other combinations.The activities of POD,SOD and CAT in leaves of combination Ganwu 2/Ganshi 83-1 and Ganwu 2/Gan 8 were significantly higher than those of the other three combinations,and the ACP activity of combination Ganwu2/Ganwu 2 was the highest;the uptake and utilization efficiency of N,P and K in roots of combination Gan 8/Ganwu 2 was the higher than others combinations.3.The effect of P on the morphological index,content of chlorophyll and K uptake and utilization efficiency of Camellia oleifera was related to the variety of scion and rootstock,the photosynthetic characteristics and N and P uptake and utilization efficiency was mainly related to the variety of scion during the trial period.4.Principal component analysis was used to analyze the decrease of morphological and physiological characteristics of each rootstock-scion combination under P deficiency treatment compared with that under P application.The comprehensive score ranked as follows:combination Gan 8/Ganwu 2>combination Ganwu 2/Gan 8>combination Ganshi 83-1/Ganwu 2>combination Ganwu 2/Ganshi 83-1>combination Ganwu2/Ganwu 2.The comprehensive score of the five rootstocks was quite different.It is speculated that Gan 8/Gan Wu 2 is more sensitive to phosphorus,which is an efficient combination of phosphorus.Comparing with the comprehensive score,the response to phosphorus of Camellia oleifera grafted on bud seedling rootstock is not only related to the variety of scion,but also affected by rootstock and stock-scion combinations.