| Castanea henryi belongs to Castanea of Fagaceae,which is one of the important woody grain trees in southern China.At present,there are some problems in the breeding of chinquapin seedlings,such as long seedling-raising cycle,incompatibility in the later stage of grafting,and susceptibility to diseases.Rootstock-scion combination not only affects the quality of chinquapin seedlings,but also affects its adaptability.Screening good rootstocks with affinity and high photosynthetic efficiency is of great significance to the development of chinquapin industry.Therefore,the effects of different rootstocks on the growth and photosynthesis of chinquapin seedlings were studied,taking 9 different sources of C.henryi,C.mollissima and C.seguinii seedlings,and 2-year-old C.henryi and C.mollisima in Hunan as rootstocks,respectively.We evaluated the early compatibility of different grafted seedlings,which provided a scientific basis for screening suitable rootstocks for chinquapin.The main results showed as follows:(1)The survival rates of 9 rootstock-scion combinations were different.Among them,the highest survival rates were 70.3%for C.seguinii(ynml)from Yunnan province,and then survival rates were 66.0%and 60-.4%for C.mollissima(ddbl)from Dandong in Liaoning and C.henryi(syzl)from Shuiyuan in Hunan province,respectively.The external morphology and internal structure of rootstock and scion healing were observed.The healing time of rootstock and scion was 24 days.The average seedling height of syzl,ddbl and Qingyuan chinquapin(qyzl)was the highest,37.40 cm,32.51 cm and 26.00 cm,respectively.The average seedling height of ynml and C.seguinii(gxml)from Guangxi province was the lowest,16.13 cm and 17.86 cm,respectively.The daily average photosynthetic rates of different rootstock-scion combinations were different.Among them,the daily average net photosynthetic rates of qyzl,syzl and ynml were the highest,which were 7.43μmol·m-2s-1,6.15μmol·m-2s-1,5.96μmol·m-2s-1,respectively.The daily average net photosynthetic rates of gxml,ltb1 and C.seguinii(gzml)from Guizhou province were the lowest,which were 4.46μmol·m-2s-1,4.93μmol·m-2s-1 and 5.25μmol·m-2s-1,respectively.Therefore,ynml,ddbl and syzl were better rootstocks for C.henryi ’Huali 3’.(2)The survival rates of two-year-old rootstocks with different rootstocks were different.The survival rates of chestnut rootstocks(zl-H3)in C.henryi from Hunna province was 87.5%,and that of chestnut rootstocks(bl-H3)in C.mollissima from Hunan was only 46.7%.The average seedling height of zl-H3 and bl-H3 were 118.46 cm and 104.05 cm,and the average ground diameter were 15.83 mm and 10.35 cm,respectively.However,there were significant differences between the grafting group and the control group.The average seedling height of C.henryi seedlings(zl-ck)and C.mollissima seedlings(bl-ck)from Hunan province were 62.24 cm and 41.94 cm,with an average ground diameter of 5.71 mm and 6.69 mm,respectively.Different rootstocks had certain effects on the photosynthesis of chinquapin seedlings.It was found that there was no significant difference between the grafted groups,but there was a certain difference between the control group and the grafted group.The daily average net photosynthetic rates of bl-H3 and zl-H3 were 7.57μmol·m-2s-1 and 7.37μmol·m-2s-1,respectively.The daily average net photosynthetic rates of bl-ck and zl-ck were μmol·m-s-1 and 6.09μmol·m-2s-1.Hence,two years older chinquapin seedings from Hunan can be used as a suitable rootstock for C.henryi ’Huali 3’.In short,the method of splitting bud and seedling rootstocks and two-year-old rootstocks can be used to cultivate seedlings for C.henryi in production.The suitable rootstocks of ynml,ddbl and chinquapin from Hunan were preliminarily screened out as C.henryi ’Huali 3’. |
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