Author name:
اسراء عبد الرزاق حميد السامر
Supervisor name:
صبيح داود محمد العطبي | محمد حمزة عباس
Abstract:
The present study was conducted to evaluate the effect of different concentrations of the growth regulators 2, 4 - D; Dicamba and NAA on the induction of date palm (Phoenix dactylifera L.) primary callus Hillawii cv., by analyzing morphological, biochemical; anatomical and molecular responses. Three concentration of 2, 4 - D (10; 50 and 100 mg/L), Dicamba (1; 5 and 10 mg/L) and 30 mg/L of NAA were examined during the course of this study. in addition, several antimicrobial agents were selected to evaluate their morphological and biochemical impacts on the primary callus of date palm including the antibiotics (Gentamycin 50 mg/L and Chloramphenicol 50 and 100 mg/L), as well as, the fungicides (Switch 1 g/L and Beltanol 1 ml/L), After induction of the primary callus from each treatments, the following results were obtained : 1. The results showed that the treatments with 2, 4 - D at 10 mg/L and Dicamba at 1 and 5 mg/L did not stimulate any callus growth over the time of incubation on MS medium.2. It was evident that the treatments of different growth regulators have a significant effect on the initial period (day) for callus initiation, the shortest period have been obtained with the low concentration of 2, 4 - D (50 mg/L) and Dicamba (10 mg/L) which were 67.57 and 66.75 days, respectively, while the high concentration of 2, 4 - D (100 mg/L) led to increase this period significantly up to 120 days.3. Both fresh and dry weight of date palm primary callus decreased significantly at the treatment of high concentration of 2, 4 - D (100 mg/L) up to two folds compared to the treatment at low concentration of 2, 4 - D (50 mg/L), similar trend of results were found with browning percentage and intensity.4. Biochemical analysis of produced date palm primary callus revealed that the high concentration of 2, 4 - D (100 mg/L) led to a significant increase in the total content of carbohydrates; Proline, Peroxidase activity and Phenolic compounds which considered as a stress indicators, and another decrease of total soluble proteins and free amino acids was accompanied with this treatment compared to the same growth regulator at low concentration and Dicamba treatments.5. Anatomical study revealed that asignificant damage was caused by the high concentration of 2, 4 - D (100 mg/L) on date palm primary callus, this damage was evident from the abundant and distribution of tannins compounds across the primary callus tissues, thus, was accompanied with high percent of browning, compared with the treatments of 2, 4 - D at low concentration, Dicamba and NAA.6. The analysis of Protein profile revealed the similarity between the patterns of control treatment (juvenile leaf of Hillawii cv.) and 2, 4 - D at low concentration, as well as, Dicamba. Similarity indices results for protein profile of date palm primary callus proved the genetic similarity of 100% between control treatment and both 2, 4 - D (50 mg/L) and Dicamba ones, while, the lowest similarity percentage was observed with high concentration of 2, 4 - D (100 mg/L).7. The results of RAPD marker analysis of the extracted genomic DNA form date palm primary callus using four deca oligonucleotide primers showed the efficiency of three primers (OPAR3; OPAR8 and P.650) in their amplification of examined DNA,. RAPD profile revealed an identical matching between control treatment and 2, 4 - D at low concentration, followed by Dicamba and NAA auxins, while, the increasing in 2, 4 - D concentration up to 100 mg/L led to disappearance and the appearance of new DNA bands compared to control treatment, with a highest genetic distance among other treatments.Similarity coefficient analysis showed that the highest genetic similarities were found between control treatment and 2, 4 - D (50 mg/L) with similarity index of 96% , followed by Dicamba and NAA treatments with indices of 74 and 66%, respectively, the lowest similarity index was obtained between control and 2, 4 - D at high concentration which was 27%.8. The screening results of antimicrobial agents showed that the treatment with Switch fungicide (1 g/L) and Gentamycin antibiotic ( 50 mg/L) did not stimulate any callus growth over the time of incubation on MS medium supplemented with either 2, 4 - D or Dicamba.9. Beltanol fungicides (1 ml/L) treatment had a negative effect on the initiated primary callus either by 2, 4 - D or Dicamba, its treatment led to a high significant reduction in total solubleprotein and free amino acid content compared to control results, while an increase of total carbohydrates, Phenolic compounds, Proline and Peroxidase activity was detected with Beltanol fungicide.10. The Chloramphenicol treatment at low concentration (50 mg/L) showed positive results on the growth of primary callus at 2, 4 - D or Dicamba auxins according to morphological and biochemical analysis.
