Regeneration Plantlet For Quercus Variabilis In Vitro

Quercus variabilis, the primary source of industrial cork, is one of the most important economical woody species exclusively occurring in China. Q. variabilis is propagated mainly by seeds. Owing to severe invasion by weevil, difficult to storage seeds over a long period of time, as well as difficult to cutting, Q. variabilis stands are regenerated mostly nature for the moment. As a result of excess deforestation, its resources were exhausted. So it is highly significative to establish a reliable in vitro regeneration plantlet system for gene resource preservation and rapid propagation excellent clones of Q. variabilis. .Meantime this study is the first study of Q. variabilis tissue culture in China.Seedlings 4-6 months were used as a source of initial explants. We studied on the effects of factors such as pre-sterilization, brownish inhabitor, media, plant growth regulator, on initiation culture, subculture and rooting, as well as influence of growth regulator induce callus from leaves. The results are as follows:1 The original explants were surface-sterilized by agitating in a solution of NaOCl (10% active chlorine) for 10 min, followed by wash two times in sterile distilled water, then agitated in 0.1% HgCla for 2 min, and finely rinsed three times with sterile distilled water.2 Only 5.7% explants died of brownish in media supplemented with 0.1% Vc. It was proven efficient to inhabiting brownish.3 Media with low concentration of salt ions, such as GD, WPM, BTM with 0.2mg/l 6-BA are more suitable for initial culture than other media richer in salts. Shoots in these cultures were healthy -looking with large, well development leaves and more shoots.4 Adding low concentration 6-BA to the medium in subculture improves the multiplication of shoot. Shoots failed to elongate often assuming the forms of tiny rosettes or closed buds which were very different to subculture or leaves were curl, vitrified symptoms.5 The elongation of shoots was greatly promoted by GA3 3.0~5.0mg/l in medium. If GAs was added in subculture successively, plantlet will become trifling and leaves developed incompletely were not suitable to root.6 If the same medium (BTM) were applied successively, the plantlets were aging or keep quiesce. Death rate was more than 50%. In order to avoid the explants losing vigor, we replaced BTM with WPM.7 The quality of the root system was better on WPM with NAA O.lmg/1, IB A 0.25mg/l than on MS or 1/2MS. Rooting rate is to 78.6%. Rooting rate was low on WPM with NAA.These roots mostly were induced from callus and not suitable to transplant.8 Adding 2,4-D in medium can more effectively induce callus than NAA and IBA from leaves in vitro. The quality of callus was better on WPM with 2,4-D 1.5mg/l, 6-BA 1.0mg/1 than on MS or 1/2MS. There were no getting any regeneration plantlet from callus in this study..