Research On Growth Seedlings Of Tung Tree By Hypocotyle Grafting

Tung tree is one of the four major woody oil tree species in China,it seeds have a high oil content,and the tung oil obtained after pressing is a high-quality raw material for the manufacture of green coatings.At present,the source of seedlings in the cultivation of tung tree is mainly the seedlings sown by seeds,and the offspring of the seedlings cannot maintain the excellent traits of the female parent,and the forest of tung tree is often uneven after planting,resulting in low yield and low efficiency,which seriously hinders the process of improved seed utilization of tung tree,in view of the above production problems,the seedlings cultivated from Millennium seeds and tung tree seeds were used as rootstocks,and the current year-old semi-woody stem segments with buds of the off spring of ’Hua Tong No.1’ were used as scions,and on this basis study the effects of different rootstock species,grafting methods,grafting film types,grafting periods,seedbeds and transplanting heights on the grafting success of the seedling rootstocks for two consecutive years,and the microscopic anatomical structure of wound healing after grafting was observed.the germination anvils of the seedlings the successful establishment of the grafting and breeding technology system of oil tung sprouts and seedlings provides a new way for the breeding of fine seeds of oil tung seeds.The main findings are as follows:1.Effects of different grafting treatments on the survival rate of grafted seedlings of tung tree.(1)The germination rate of seeds of Millennium is higher than that of tung tree overall,when the sand storage density of Millennium seeds was 1111 plants/m2,the germination rate of rootstock was the highest 81.6%,which was 28.9%higher than that of 2500 plants/m2,the difference was significant(P<0.05),and the hypocotyl thickness was 6.00～8.00 mm and the root length was about 13 cm,the rootstock was the most suitable for grafting.(2)Under the condition that other external factors are better,the survival rate of tung tree grafting was more than 89.0%with both tung tree and Millennium as rootstocks,use the seedlings cultivated from Millennium seeds as rootstocks,The split grafting with plastic film was 184.0%higher than that of bonding,and the difference was significant(P<0.05),the survival rate of split grafting with plastic film was 58.7%higher than that of jointing.,and the difference was significant(P<0.05).(3)The length of the upper axillary buds,lower part axillary buds and petiole of scion is 1.0 cm,3.0 cm and 0.5 cm respectively,which are suitable for grafting on tung tree shoot rootstock;the rootstock splitting incision length is 1.5 cm,the height of transplanting seedbed is 15 cm,the light transmission rate of the shade net is 25%,and the grafting union should be above the ground at the time of transplanting.(4)Different grafting periods had significant effects on the survival rate of tung tree by hypocotyle grafting,the survival rate of grafting in early June was 51.5%higher than that in mid-May,with significant differences(P<0.05).2.Effects of different grafting treatments on the late growth of grafted seedlings of tung tree.(1)Different grafting time,different seedbed height,different scion,petiole and incision length,and different transplanting height had basically no significant effect on the growth and development of grafted seedlings.(2)By observing the growth process of axillary buds and the anatomical structure of callus at the graft union,we learned that the wound was partially healed and the axillary buds began to expand after 10 d of grafting,and the axillary buds sprouted new leaves after 20 d,and the wound heals completely after 70 d,at this time,use a blade to gently cut the plastic film along one side and remove all the plastic film so that the grafted seedlings can grow normally in the later stage.(3)The net photosynthetic rate Pn value of grafted seedlings of tung tree differed significantly under different treatments(P<0.05),the highest Pn value was 17.21 μmol·m-2·s-1 when the petiole length was 1.0 cm,which was 37.1%higher than that of 2.0 cm incision length,which was significantly different(P<0.05)after 60 d of seedling growth,the highest Pn value was 13.86 μmol·m-2·s-1 when the seedbed height was 10 cm,which was 50.5%higher than that when the transplanting height was buried in the ground with the interface and the difference was significant(P<0.05)after 90 days of seedling growth.In this paper,the grafting technology system of anvil seedlings of tung tree was successfully established,and the seedlings grew well,and the overall survival rate of a large number of seedlings in the field in June could reach more than 70.0%,which provided a practical way for the asexual breeding of tung tree seedlings in the future.