Effect of growth regulators, salinity and chitosan on vegetative traits for the shoots of rootstocks of citrus (swingle citrumelo)‎ multiplied in vitro

الملخص EN

The two factorial experiments were conducted in the tissue culture laboratory of the Plant Production Department / Al-Mussaib Technical College during the period 2018-2019 with the aim of proliferating the rootstocks of the citrus Citrumelo in vitro, where the first experiment was to study the effect of different concentrations of benzyl adenine BA (1, 2, 3 and 4 mg.

L-1) in the studied vegetative growth traits.

As for the second experiment, it was to study the effect of three concentrations of NaCl salt (0, 50 and 100 mmol) by adding several concentrations of chitosan to the agricultural medium (0, 5, 15 and 25 mg.

L-1) and study the effect of the interaction between the factors in vegetative growth for the resulting plants.

The plants were multiplied by using the single node as an Explant plant, as the Node were taken 1.5-2 cm long and then immersed in an antioxidant solution (100 mg.

L-1 ascorbic acid + 150 mg.

L-1 citric acid), Then the explant was sterilized with ethanol solution (70% concentration) for 10 seconds, after which they were immersed in 1% sodium hypochlorate solution for 15 minutes.

Then the explant was immersed in distilled water three times for 3 - 5 minutes each time to ensure the removal of the harmful effect of alcohol.

The explant was culture 1 cm long containing single nodes in MS culture medium.

The seedlings were incubated at a temperature of 25 ± 2 and a light period of 16 hours.

The results showed that the addition of chitosan reduced the harmful saline effect of cultures, where the combination (25 mg.

L-1 chitosan + 50 and 100 mmol NaCl) significantly increased the average length of shoots, the weight of the fresh and dry plant, the average water content and the chlorophyll content of the Cultures reached ( 2.55 cm, 305 mg, 48.4 mg, 285 mg and 1, 301 mg.

fresh weight), compared to other interaction factors.

In the second experiment, the concentration of 2 mg.

L-1 BA excelled in the percentage of multiplication, the number of shoots and the length of the shoots (90% , 4.2% and 2.9 cm) and the concentration 3 mg.

L-1 in the average of fresh and dry weights of the shoots (263 and 43 mg).