| Abstract: |
Shoot tips of 1.5 cm long of Taxodium distichum L. sterilized with mercuric chloride 0.2% for 10 min followed by immersing in 5, 10 or 20% Clorox for 20 or 40 min. did not show contamination, while survival percentage decreased down to 70% with the highest Clorox concentration of 20%, and was 100% with low Clorox concentration of 5% for 5-20 min.MS medium free of growth regulators showed a good sprouting of the buds and was considered a good establishment medium. During the multiplication of the obtained shoots from the establishment stage, MS medium supplemented with 2, 4-D or 8 ppm kinetin, benzyle adenine or 2-ip showed that the highest shoot number/explant (5.2 shoots) was obtained by 8 ppm 2-ip, followed descendingly by either 2 or 4 ppm BA (3.0 – 3.06 shoots,respectively), while the least number was due to control or kinetin treatments.All cytokinin concentrations decreased shoot length and did not show any callus formation on explant base. Using progesterone in multiplication stage at 0, 2.5, 5 or 10 ppm did not show multiplication. Also, using diphenyl urea at 0.25, 0.5 or 1 ppm plus 8 ppm 2-ip was uneffective compared with 8 ppm 2-ip alone.At rooting stage using of IAA, IBA or NAA as rooting agents in full or 1/2 MS strength and activated charcoal or low as well as high sucrose concentration,led to rooting percentage reached 14% with 1 ppm NAA in 1/2 MS medium. Also, pulsing shoot bases in 0.5, 1, 2 or 4 ppm NAA for 24 h. then culturing them in 1/2 or full MS did not show rooting, moreover, continuous film of 0.5, 1, 2 or 4 ppm of NAA on MS medium surface containing the same concentrations did not show rooting response. The rooted plantlets could be acclimatized on peat moss and sand medium (1:1, v/v).Culturing of shoot tip (1.5 cm length) of Cupressus macrocarpa Hartw. on different BA or Kin. concentrations either low than 0.5 ppm or high up to 16 ppm in MS media and also using of 0.5 or 1.0 ppm BA in different media types i.e. MS medium, MS multiplication medium, Gamborg (B5) medium, Chee and Pool medium and Mccown Woody Plant Medium did not prove any efficiency on shoot or root production. Also, different auxin types as IAA, NAA and IBA in MS media gave the same result. All those treatments turned shoot tip to a mass of callus without any differentiation and less callus formation was obtained on MS media free from growth regulators and at last the explants lost their viability and turned brown after 10 weeks.
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