تأثير بعض منظمات النمو ونوع الأضاءة والسكروز في اكثار وانتاج بعض مركبات الأيض الثانوي لنبات الستيفيا Stevia rebaudiana خارج الجسم الحي

The effect of some growth regulators and the type of lighting and sucrose on the micro propagation and production of some secondary metabolite

This study was carried out in the Plant Tissue Culture Laboratory of the College of Agriculture – University of Karbala, and HPLC analyzes were completed in the White Fields Company for Investments, Environmental and Engineering Studies for the period from 2022 to 2023. The study included the suse of plant tissue culture technique in propagating the Stevia plant and stimulating it to increase the production of glycosides of medical importance. The study was carried out in three stages after conducting the sterilization process: the first included the establishment of vegetative shoots by using different combinations of plant growth regulators (Auxins and Cytokinines). The second stage was carried out by exposing the vegetative offshoot cultures to several types of lighting and different concentrations of sucrose to stimulate it to increase the production of secondary metabolites. The third stage included the rooting of the vegetative offshoots obtained from the multiplication stage by cultivating them on nutrient media equipped with different concentrations of MS and IBA salts. Then the tissue plants were acclimated. All phases were carried out in independent factorial experiments within a completely randomized design (CRD). The results can be summarized as follows:
The best treatment for sterilizing plant parts is sodium hypochlorite (NaOCl) at a concentration of 1% for 15 minutes.
The growing tops as a plant part used in the emergence stage gave the highest response amounting to 70.00%, while the lateral shoots gave the highest response amounting to 54.68%.
The nutrient medium supplemented with BA at a concentration of 3 mg L-1 was the best in increasing the number of branches, their length, the number of leaves, and the tender weight of the vegetative, which reached 33.35 branches of Plant-1 and 8.20 cm, and 109.77 leaves of Plant-1 and 7.46 mg, respectively, while The concentration of 2 mg l-1 achieved the highest rate of dry weight of the shoot amounted to 3.94 mg.
The concentration of 0.3 mg l-1 NAA achieved the highest mean of the number of branches, their length, the number of leaves, and the fresh and dry weight of the vegetative, which reached 30.87 branches Plant-1, 7.65 cm, , 94.55 leaves Plant-1, 6.98 mg, and 3.85 mg, respectively.
Concentration 4 mg l-1 BA achieved the highest average concentration of chlorophyll a and total chlorophyll a which reached 1.37 mg g-1 and 2.47 mg g-1 respectively, while the concentration of 3 mg l-1 BA achieved the highest average of chlorophyll b amounted to 0.93 mg g-1.
The concentration of 0.3 mg l-1 NAA achieved the highest average concentration of chlorophyll a, b and total, which reached 1.21 mg g-1, 0.87 mg g-1 and 2.09 mg g-1, respectively.
The concentration of 4 mg g-1 BA achieved the highest percentage of soluble and insoluble carbohydrates, which reached 19.48% and 45.88%, respectively.
NAA, at a concentration of 0.4 mg g-1, achieved the highest percentage of soluble carbohydrates, amounting to 18.22%, while the concentration of 0.3 mg g-1 achieved the highest percentage of insoluble carbohydrates, amounting to 43.74%.
The concentration of 4 mg g-1 BA achieved the highest mean concentrations for Stevioside and Rebaudioside A, which reached 2461.40 and 1475 μg g-1, respectively.
The concentration of 0.4 mg g-1 NAA achieved the highest mean concentrations for Stevioside and Rebaudioside A, which reached 1659.20 and 1293 µg g-1, respectively.
The colored LED lights achieved the highest rate of the number of branches, their length, the number of leaves, and the fresh and dry weight of the vegetative, which reached 38.66 branches plant-1, 10.73 cm, 147.30 leaves plant-1, 10.65 mg, and 4.17 mg, respectively. When the medium was treated with different concentrations of sucrose, the concentration of 45 g l-1 achieved the highest rate of the number of branches, their length, the number of leaves, and the fresh and dry weight of the vegetative total, which reached 38.47 branches Plant-1, 7.63 cm, 124.38 leaves Plant-1, 8.82 mg, and 3.23 mg respectively.
The colored LED lamps achieved the highest concentrations of chlorophyll a and b, totaling 2.29, 1.91 and 4.20 mg g-1 respectively. When the media was treated with different concentrations of sucrose, the concentration of 60 g l-1 achieved the highest average concentration of chlorophyll a, b and total which reached 2.25, 1.98 and 4.23 mg g-1 respectively.
The colored LED lamps achieved the highest percentage of soluble and insoluble carbohydrates, which amounted to 21.52 and 48.15% respectively. When the medium was treated with different concentrations of sucrose, the concentration of 45 g l-1 achieved the highest percentage of soluble and insoluble carbohydrates, which amounted to 20.50 and 48.83%, respectively.
The colored LED lamps achieved the highest levels of Stevioside and Rebaudioside, which amounted to 3000 and 2751 µg g-1 respectively. When the medium was treated with different concentrations of sucrose, the concentration of 60 g l-1 achieved the highest rate for the two compounds of Stevioside and Rebaudioside, which amounted to 2740 and 2167 μg g-1, respectively.