Effect of Culture Medium in Callogenesis from Adult Walnut Leaves (Juglans regia L.)

Abstract

Todefinepreliminaryaspectsofwalnut�(Juglans regia L.) callogenesis in indirect propagation systems, this work analyzed callogenic induction in adult leaves of walnut in broadleaf trees (BTM), Murashige and Skoog (MS) Driver Kuniyuki Walnut (DKW) and Woody Plant (WPM) media. Leaf segments of 1 cm 2 , previously sterilized, were placed in each culture medium, supplemented with 21.4 µM naphtalene acetic acid (NAA) and 8.8 µM 6-benzylaminopurine (BAP). A completely random design was used; the experimental unit was a Petri dish with six callus explants. Each treatment was composed of seven Petri dishes. Callogenesis (%), nodular calli (%) and histology of calli explants were evaluated at 4 weeks by staining 10 µm slices with safranine-fastgreen. There were nosignificantdifferences�(α�=�0.05)�incallogenesisamongevaluatedmedia;�butnodularcallipercentageswere� significantlyhigherinBTM�(75%)�andWPM�(63%).�OnlyincalliobtainedintheBTMmediumdidthehistology� show the presence of meristematic zones, but without external expression. These results indicate that the medium influencesthemorphogeniccharacteristicsofresultantcallus.�CalliproducedinBTMpresentedbettermorphogenic� potential, with meristems at primary stages of organization.