Research On Cutting Propagation Of Lagerstroemia In The Growing Period And Establishment Of Regeneration System

Lagerstroemia indica is a deciduous shrub or small tree of the Lythraceae family.The flowers are large and colorful,and they bloom in the summer with few flowers.It is an important ornamental tree species.At present,there are many researches on the cutting propagation of L.indica,but there are no reports about the research of L.indica cuttings to form flowers at one time.In terms of tissue culture,a variety of rapid propagation systems for L.indica stems have been established,but there are few reports on the regeneration of L.indica.This experiment started with cuttings and regeneration,and explored the rooting of L.indica cuttings,transplanted survival and flower formation,quality evaluation of transplanted seedlings and regeneration of L.indica.Provide technical support for the promotion and breeding of L.indica,and lay the foundation for the establishment of L.indica variety improvement and transformation system.The main research results are as follows.1.Research on cutting propagation during growth period(1)L.indica ‘Dwarf’ and L.indica ‘Cheng Du’ belong to the skin rooting type.The cutting rooting rate of L.indica ‘Dwarf’in the combination of length of 8cm-10 cm + leaf cutting 1/2 + peat soil 1: vermiculite 1 reached 100%,and the average number of roots was 11.3.The rooting rate of L.indica ‘Cheng Du’ in the combination of length13cm-15 cm +leaf cutting 1/2 +peat soil 1: vermiculite1 was 52.4%,and the average number of roots was 4.5.Roots number and roots length that KIBA8: NAA2 treated are significantly higher than that of IBA treated,roots length and roots thickness are significantly higher than that of KIBA treated;thick cuttings(0.8cm-1.0cm)root number is significantly higher than fine cuttings(0.5cm-0.8cm);The rooting rate and number of roots in the upper fringe are significantly higher than those in the lower fringe;the root number and root thickness of the long branches(13cm-15cm)are significantly higher than that of the short branches(8cm-10cm).(2)The Whit III belongs to the skin rooting type.The rooting rate of biennial cuttings in peat soil 1: vermiculite 1 is 91.2%,and the average root number is 14.0;the current cuttings in peat soil 3: perlite 1,incision oblique shear,KIBA 1000 mg/L treatment for 10 seconds,the rooting rate is 60.0 %,the average number of roots is 11.0.(3)The results of the research on the one-time flower-forming technology of cuttings showed that the cutting rooting rate of L.indica ‘dwarf’ in the combination of length 13cm-15 cm + 2 leaves + peat soil 3: vermiculite 1 reached 90%,Transplanting with non-woven bag in 17 d after cutting,apply 0.1% ‘Huaduoduo No.2’ fertilizer every7 days before the second-level shoots germinate(about 10 days after transplanting).22 days after transplanting,the first flowers blooming,the flowering rate reached 72.5%,and the flowering period delayed until October 17.L.indica ‘Chengdu’ and Whit III did not bloom after transplanting.(4)After transplanted for 70 days,the average seedling height of L.indica ‘dwarf’was 22.9cm,and the average crown width was 25.4cm.Taking seedling height and crown width,the number of branches as the main indicators and flowering rate as a reference indicator,the quality of transplanted seedlings is evaluated as Grade I seedlings: seedling height ≥ 25 cm,crown width ≥ 25 cm,number of branches ≥ 3;Grade Ⅱseedlings: Seedling height ≥20cm,crown width ≥20cm,branch number ≥3;Grade III seedling: seedling height ≥15cm,crown width ≥15cm,and branch number ≥2.2.Optimization of tissue culture and establishment of regeneration system(1)The stem segments of the current year were sterilized with 0.1% mercury for 8minutes.The primary medium and the secondary medium were MS+6-BA1.0mg/L+NAA 0.1 mg/L,and a large amount of cluster buds was obtained after 4-5 times of subculture.cluster buds with abnormal growth after several successive generations,after cultured in 1/2MS+6-BA1.0 mg/L+NAA0.1 mg/L optimized medium,the leaves of the tissue culture seedlings obtained are green and stretched,and the growth is strong.The rooting effect of NAA is better than that of IBA.The rooting rate of seedlings inoculated in 1/2MS+NAA0.5 mg/L is 94.4%,and the average root number is 6.3.(2)After the leaves of tissue cultured seedlings inoculated in MS+6-BA1.0mg/L+IBA0.5 mg/L,the callus rate reached 83%.The callus was light yellow-green,granular and moist.Using 20 g/L sucrose as the carbon source,the callus rate of leaves is78%,and the callus is light yellow-green,granular,moist,and in the best condition.The callus rate of embryos inoculated in MS+2,4-D1.0 mg/L+6-BA0.5 mg/L+NAA0.5 mg/L was 100%,and the callus was pale yellow-green,granular and moist.the callus rate of cotyledons inoculated in MS+6-BA1.0 mg/L+2,4-D0.5 mg/L+NAA0.5 mg/L was 100%,the callus was yellow-green,light yellow,lumpy,moist.The leaf callus inoculated in1/2MS+6-BA1.0 mg/L+NAA0.2 mg/L differentiate adventitious bud rate reached 75%,and the average bud number was 1.8.The green granular callus at the base of the stem inoculated in 1/2MS+6-BA1.5 mg/L+NAA0.75 mg/L differentiate adventitious bud rate reached 100%,and the average number of buds was 5.6.