Ahmad Sharif; Seyyedeh Mahdiyeh Kharrazi; Saba Nejatizadeh; Azadeh Khadem; Maryam Moradian
Abstract
Introduction: In traditional agriculture, a high concentration of nutrients is generally available to the plant, and a large amount of it will be leached out and is not available to the plant. But, if properly managed, the nutritional needs of the plant can be identified; it can increase the efficiency ...
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Introduction: In traditional agriculture, a high concentration of nutrients is generally available to the plant, and a large amount of it will be leached out and is not available to the plant. But, if properly managed, the nutritional needs of the plant can be identified; it can increase the efficiency of fertilizer use and also prevent the environmental pollution caused by excessive use of chemical fertilizers in the country. Therefore, the aim of this study was to increase the fertilizer utilization efficiency by choosing optimal fertilizer treatment and its optimum level for acclimation and optimum growth of gerbera tissue culture plantlets.
Material and methods: In the first experiment, different fertilizer treatments with different proportions of NPK were evaluated in a completely randomized design with 10 replications. In the second experiment, the different concentrations of the secondary group treatment (0.5x, 1x and 1.5x) were evaluated to determine the optimum level of fertilizer treatment. This experiment also was conducted in a completely randomized design with 15 replications. At the end of each experiment different parameters such as leaf number, petiole length, shoot dry and fresh weight, main root number, root length, secondary root number, root volume, root dry and fresh weight, chlorophyll a, b and total content were measured. Data preparation was done in Excel and data analysis was performed using the Jump 8 software. Mean comparison between treatments was performed with LSD test at 5% probability level and charts were drawn using Excel program.
Results and discussion: The results showed that the maximum root length, root volume, root dry and fresh weight and secondary root number was obtained from plantlets that was treated by the fertilizer treatment of the second group: K2SO4 (0.22 mM), KNO3 (3.62 mM), KH2PO4 (0.71 mM), NH4H2PO4 (0.35 mM), NH4NO3 (0.53 mM), Ca(NO3)2,4H2O (1.48 mM), MgSO4, 7H2O (0.4 mM), MnCl2, 4H2O (0.0049 mM), H3BO3 (0.020 mM), ZnSO4 (0.0061 mM), CuSO4, 5H2O (0.00048 mM), NaMoO4, 2H2O (0.00058 mM), FeSO4, 7H2O (0.0348 mM), Na2EDTA (0.0384 mM). So among the different fertilizer treatment, application of the fertilizer treatment of the second group was recommended. Calculation of nitrate and ammonium content used in six fertilizer treatments showed that the amount of ammonium used in fertilizer had a significant effect on root number and root dry weight. The maximum root number and root dry weight were observed in the second fertilizer group and then in the first fertilizer group. Urea was not used as a source of nitrogen in the fertilizer formula of these two treatments, while in other fertilizer treatments; urea fertilizer was used in addition to other sources of nitrogen supply. Since urea is converted into ammonium before its absorption by the plant, its application in the fertilizer formula has an effect on the amount of ammonium used in the fertilizer composition. It increases the ratio of ammonium to nitrate in fertilizer composition, which in turn influences root function. The ratio of potassium to phosphorus in the research of Khalaj et al. (4.40) is approximately as the same as the ratio of potassium to phosphorus used in the second group fertilizer treatment (4.50). The results of this ratio were also corresponded to Zheng et al. (4.6), Paradikovic et al (4.4), Hahn et al (4), Savvas and Gizas (4.8).The results of second experiment showed that plantlets grown under 1.5x concentration of second group fertilizer had better growth indices than two other treatments and had higher means in terms of root and shoot dry weight and petiole length. After counting the number of produced leaves at the end of the experiment, signs of leaf necrosis was observed under some treatments. Plantlets treated with 1 and 0.5 x concentrations of the second group treatment showed the highest incidence of leaf necrosis. Application of 1.5 x concentration of the second group treatment resulted in a 40% decrease in leaf necrosis symptoms compared to the other treatments. Also, the highest percentage of healthy leaves was obtained from 1.5 x concentration of the second group treatment, which showed a significant difference with the other treatments.
Conclusion: Generally, for the purpose of acclimation and optimal growth of gerbera tissue culture plantlets, fertilizer treatment of the second group {15(N), 10(P2O5), 30(K2O), 11.10(CaO), 2.10(MgO)} at a concentration of 1.5x is recommended.
