Vegetative Propagation Of Quercus Variabilis By In Vitro Cutting

Quercus variabilis Bl is a unique eco-economic tree species and an important cork resource in China.Seed propagation is generally used,but since the seeds of Q.variabilis are easily endangered by weevil and cannot be stored for a long time,and it is difficult to use conventional cutting propagation to root,it is still natural regeneration.The research on the technique of asexual propagation in vitro cutting is of great significance for the conservation of germplasm,genetic improvement and the promotion and utilization of excellent genotypes.The 1-year-old seedlings and shoots flushed on branch segments as initiation explants,this paper studied the aseptic shoots establishment,browning treatment,plant growth regulators combination and concentration,inducingrooting as well as shoot proliferation and differentiation for Q.variabilis.The results were as follows:1.The juvenile nodal segments were surface-sterilized by agitating in a solution of 75%alcohol for 30s,then agitating in 0.1%HgCl₂ for 5 min;the mature nodal segments were surface-sterilized by agitating in a solution of 75%alcohol for 45s,then agitating in 10%NaClO（Effective chlorine 8%）adding 2 drops of Tween 20 for 10 min.2.In the initial culture stage,the browning rate of juvenile nodal segments was lower than mature nodals.Adding 0.3 g/L ascorbic acid to the medium could significantly reduce the browning rate of juvenile nodal segments;0.1 g/L PVP could effectively inhibit the browning of adult nodal segments.3.Using WPM as the basic medium,the addition of 0.2 mg/L of 6-BA was beneficial to the germination of axillary buds.The number of clumpy buds in juvenile nodal segments can be as many as four and two in mature age.High concentration of 6-BA was not conducive to the germination of two different explants,which was characterized by abnormal axillary shoots and callus.4.Proliferation and culture of mature nodal segments and juvenile nodal segments of Q.variabilis:comprehensive consideration of the proliferation number of shoots,length of axillary shoots and quality of shoots:WPM as the basic medium,which adding 0.8mg/L6-BA and 0.02mg/LNAA,the proliferation number and length of axillary shoots were better than6-BA and NAA alone.The proliferation number of shoots and axillary shoots length ofjuvenilenodal segments and mature nodal segments were 8.2,6.4 and 2.07 cm,1.64 cm;When adding 6-BA 0.2 mg/L and IAA 0.01 mg/L,the number of proliferating shoots and axillary shoots of mature nodal segments andjuvenilenodal segments were 5.2,3.6 and 1.84cm and 1.67 cm,which the proliferation effect is better than adding IAA alone.5.In the rooting medium,the rooting culture of the mature nodal segments and the juvvenile nodal segments of the Q.variabilis were considered from the rooting rate,the length of the root and the quality of the rooting:WPM+0.2 mg/L NAA+1.0 mg/L IBA+3%sucrose+0.6%agar had the best rooting effect,better than NAA and IBA alone.The rooting effect ofjuvenileand mature nodal segments was the best.The rooting rate,the average number of roots per plant and the average root length were 84.3%,78.6%,4.49cm and 3.86cm.