تطوير طريقة لإكثار شجرة الباولونيا Paulownia tomentosa L. باستخدام تقانة زراعة الأنسجة النباتية

الملخص EN

A successful in vitro propagation system for rapid micropropagation of the Paulownia tomentosa has been developed using lateral buds and shoot tips excised from mature mother plant grown under field conditions as initial explants.

Explants were surface-sterilized using 70% ethanol for 1 min, then sterilized for 10 min with 25% (sodium hypochlorite 5.25%) or with 0.01% HgCl2 for 5 min, to which a drop of tween-20 for 100 ml was added.

Then explants were washed three times with sterilized distilled water.

Explants were then cultured onto MS basal medium without growth regulators for 2 weeks, whereafter they were transferred to twelve different MS basal media supplemented with growth regulators at different concentrations: BA at (2.22 and 4.44 μM), NAA at (1.45 μM and 0.48 μM), GA3 at (0.58 μM) for shoot proliferation.

Best multiplication rate of 2.85 fold was achieved every 4 weeks on MS4 containing MS medium supplemented with (4.44μM BA+0.22μM IBA+0.58 μM GA3).

Average shoot height was increased to 5.28 cm onto MS8 with a significant difference shown when IBA was replaced with NAA.

Best internodes length of 6.2, 5.9, 5.8 and 5.7 cm was achieved onto MS10, MS2, MS4 and MS5, respectively.

For rooting, 2-3 cm-long shoots were transferred to 6 different agar-gelled media (MSR0, MSR1, MSR2, MSR3, MSR4, MSR5) containing MS supplemented with IBA at concentrations of 0.0, 0.49, 1.47, 3.185, 4.9 and 5.39 μM, where roots could be induced within 2-4 weeks with a maximum rooting of 90% onto MSR2 with average root number of 3.1 and root length of 6.6 cm.

Rooted plantlets were transplanted into pots with a mixture of 2:1 (v/v) peat: perlite, covered with plastic bags and acclimatized gradually to field conditions throughout 4 weeks with 95% efficiency.

Plantlets reached about 150 cm height at the end of the first growing season and 4-5 m within 2 years.

The described method has potential to produce hundred thousands of plantlets in one year in optimal conditions, for the purposes of forestation, ornamentals and for benefiting from its multipurpose uses (wood for furniture, livestock feed, honey bees, green fertilizer …).