Studies on micro propagation of jackfruit. 1 - Behaviour of the jackfruit plants through the micropropagation stages.

摘要

In vitro and ex vitro experiments were carried out during 2004/2005 and 2005/2006 seasons and took some observations until 2007 year on jackfruit plant (Artocarpus heterophyllus Lam.) to detect the suitable methodology for micro propagating the jackfruit as a pronounced method for using different explants (apical growth, nodal segments, new leaves and cotyledons) of the available rare plant material found in Egypt for obtaining a good number of the plants diseases-free suffice for spreading this tree which have many benefits (fresh, canned or industrial food, therapic purposes, furnitures, ...etc). The effects of sterilizants (ethanol at 70%, HgCl₂ at 0.1-0.3% and chlorox at 10-20%) with aid of antioxidants (ascorbic and citric mixture) and 0.1% Tween 20 on the survival and aseptic explants %, effect of MS medium alone or with BA at 2 and 5 mg/L., NAA at 0.5 mg/L., kinetin at 0.5 mg/L. and adenine sulphate at 25 mg/L. on the callus formation and differentiation, the multiplication and the vitrification (hyperhydricity); effect of MS, 1/2 MS alone or with NAA at 0.5-2 mg/L., IBA at 0.5-3 mg/L., coumarin at 0.5-1 mg/L. and paclobutrazol at 0.5-1 mg/L. on the rooting and the vitrification; possibilities of transferring the plantlets from in vitro to in vivo or ex vitro conditions using different growing media of sand:soil (1:1, v/v), sand:peat moss (1:1, v/v) and soil:burned rice hull:fibrous sheath of date palm (1:1:1, v/v/v) by studying the effect of the growing media on the survival plants %, leaf and shoot number/plant and height of the plant; and effect of the collection dates of the explants (June-July, December-January and from 3 months old seedlings on September-October), all effects were investigated. The studies revealed that 70% ethanol for 2 min.+0.2% HgCl₂ for 5 min.+15% "Clorox" for 15 min. with the antioxidants, was the most effective sterilization treatment, as it is recorded a good percentages of the survival and aseptic explants at all studied dates and for all explants types; besides using the explants of apical growth during Dec.-Jan. and for those of 3 month old seedlings and using the explants of the new leaves during June-July, were achieved the best significant aspectic and survival explants %. The variant response to the sterilizants between the explants may be due to the different anatomical structures, especially the surface tissues. MS medium+5 mg/L. BA+0.5 mg/L. NAA+0.5 mg/L. kin.+25 mg/L. adenine sulphate and explants of apical growth and nodal segments, were recording significant values of a good callus formation and differentiation, multiplication and produced the lower significant vitrification %. NAA and kinetin seems to be necessary for callus formation but raised significantly the vitrification%. The explants collected during Dec.-Jan. and those of 3 months old seedlings gave the best callus formation and differentiation, while those of the seedlings gave significant values of a good multiplication and less significant vitrification %. Shootlets produced of either nodal segments or new leaf segments and media of 1/2 MS+3 mg/L. IBA and 1/2 MS+2 mg/L. NAA+3 mg/L. IBA+1 mg/L. paclobultrazol+1 mg/L. coumarin recorded the higher significant rooting and the lower significant vitrification %. Paclobutrazol seems to be inhibited the vitrification, while NAA, coumarin or IBA seems to be increased it. All growth estimations during the acclimatization were increased with increase of dates recording these estimations and reached to the maximum values after 3 month of the planting date, beside, the best growing mixture in the acclimatization was soil:burned rice hull:fibrous sheath of the date palm.