Study On Tissue Culture Under Open-condition And Cutting Rooting Techniques Of Three Acacia Species

This paper systematically studied the tissue culture and cutting rooting technique of Acacia mangium,A.auriculiformis,A.mangium×A.auriculiformis under open-condition,mainly including: bud inducing,rooting by tissue culture,proliferation by inducing rooting of small segments that were cut from plantlets which have rooted under open-condition,and cutting rooting under open-condition.The tissue culture and cutting rooting techniques were established.It may provide a technical support for improve the production efficiency of Acacia variety.It could be useful for simplify culture procedure and cutting down the cost and enrich the theory of culture under open-condition.It also could useful for popularization and application of forest fine varieties.In addition,the cutting rooting technique under simplify-condition was useful for studying the rooting mechanism of forest tree.The main results are as follow:(1)The optimal bacteriostats and its concentration for tissue culture were the same as it for cutting under open-condition: the optimal bacteriostats was chlorothalonil with 0.2 g·L-1,with the lowest contamination,6.94% for A.mangium,5.56% for A.auriculiformis,6.95% for A.mangium × A.Auriculiformis.It suggested that low concentration of bacteriostats can control the contamination in a low level.(2)Tissue culture and cutting rooting under open-condition share the same explant type and disinfected strategy.The 3-5 shoots with leaves were cut as explants,soaking them with carbendazim 0.8 g·L-1,then we get the highest survival rate: 90.48% for A.mangium,100.00% for A.auriculiformis and 100.00% for A.mangium × A.auriculiformis.It suggest that both low contamination rate and higher survival rate were get when soaked the shoots with carbendazim.(3)The highest germination rate under open-condition were common when gather the explant in october.The optimal medium for bud inducing was as follow: A.mangium: agar 7 g·L-1 + chlorothalonil 0.2 g·L-1 + 6-BA 0.5 mg·L-1,A.auriculiformis: agar 7 g·L-1 + chlorothalonil 0.2 g·L-1 + 6-BA 1.5 mg·L-1,A.mangium × A.auriculiformis: agar 7g·L-1 + chlorothalonil 0.2 g·L-1 + 6-BA 0.5 mg·L-1,with the same highest germination rate of 99.54%.It suggest that the same concentration of 6-BA for germination of A.mangium and A.mangium × A.auriculiformis,but germintion of A.auriculiformis need for a higher concentration of 6-BA.(4)The rooting rate of tissue culture under open-condition for A.mangium × A.auriculiformis was higher than its for A.auriculiformis,and its for A.mangium was the lowest.The optimal medium for rooting was agar 7 g·L-1 + chlorothalonil 0.2 g·L-1 + NAA 0.5 mg·L-1 + IBA 1.25 mg·L-1 for A.mangium,with rooting rate 68.75%;agar 7 g·L-1 + chlorothalonil 0.2 g·L-1 + NAA 0.1 mg·L-1 + IBA 0.5 mg·L-1 for A.auriculiformis,with rooting rate 88.25%;agar 7g·L-1 + chlorothalonil 0.2 g·L-1 + NAA 0.5 mg·L-1 + IBA 1.5 mg·L-1 for A.mangium ×A.auriculiformis,with rooting rate 97.62%.It suggest that the rooting rate of A.mangium was the lowest,and A.mangium ×A.auriculiformis showed heterosis when rooting under open conditions.(5)Rooting sub-culture for proliferation under open-condition,the proliferation index was grow up with the times of rooting sub-culture,the proliferation index of 4th rooting sub-culture was 2.99(A.mangium),3.25(A.auriculiformis),3.58(A.mangium ×A.auriculiformis).(6)The cutting rooting rate of this three Acacia Secies under open-condition was high: treatment the shoot base with IBA 0.6 g·L-1 for 2 h(A.mangium),with IBA 0.8 g·L-1 for 3 h(A.auriculiformis),with IBA 1.0 g·L-1 for 2 h(A.mangium ×A.auriculiformis),then cutting into medium which was consisted of agar 7g·L-1+ chlorothalonil 0.2 g·L-1,rooting rate were 94.33%(A.mangium),100.00%(A.auriculiformis),100.00%(A.mangium ×A.auriculiformis).It suggest that cutting rooting under simplify-condition could cultured in simplified medium with high tooting rate.