Selection of Optimal Cultivation Media for Gerbera (Gerbera Jamesonii) Growth in the Hydroponic Culture System

Considering the occurrence of successive droughts in our country and the necessity of optimal water consumption, the use of modern technologies such as closed systems to increase the efficiency of fertilizer and water use will have an effective role in reducing production costs and increasing yield. The Nutrient Film Technique (NFT) system is one of the hydroponic culture systems in which the nutrient solution is circulated continuously. In this system, a thin layer of nutrient solution will be available to the plant roots, which has a significant effect on reducing fertilizer and water consumption.

The present study was conducted to select an optimal system for cultivation of Gerbera plantlets. Plantlets were cultivated in different systems after the acclimation stage: Integrated bedding system as a closed system containing different culture media (Perlite, vermiculite, vermiculite: perlite, cocopeat: perlite and rock wool) and NFT hydroponic system as a closed system. For fertilization, the following fertilizer combination (mM) was used: K2SO4 (0.22), KNO3 (3.62), KH2PO4 (0.71), NH4H2PO4 (0.35), NH4NO3 (0.53), Ca (NO3)2,4H2O (1.48), MgSO4, 7H2O (0.4), MnCl2, 4H2O (0.0049), H3BO3 (0.020), ZnSO4 (0.0061), CuSO4, 5H2O (0.00048), NaMoO4, 2H2O (0.00058), FeSO4, 7H2O (0.0348), Na2EDTA (0.0384). The experiment was conducted in a completely randomized design with six treatments in six replicates. During six months, the growth parameters of the plants including number of leaves, petiole length, fresh and dry shoot weight, leaf chlorosis percentage, leaf necrosis percentage, flower number, flower diameter, flowering stem height, number of days to flowering, end diameter of the stalk and the middle diameter of the stalk were evaluated. 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 the Excel program.

The results showed that there was a significant difference between treatments for the number of leaves (p <0.01). Seedlings cultivated in the vermiculite culture medium produced the highest number of leaves; however, there was no significant difference between seedlings cultured in vermiculite and vermiculite: perlite media. The lowest number of produced leaves was observed in plantlets grown in the NFT system. Also, the seedlings grown in the rock wool medium had no significant difference with the NFT system. In this regard, the drought stress on plants and the consequent poor growth of plantlets reduced the number of produced leaves. The percentage of necrotic leaves in the NFT system was more than twice the vermiculite culture medium. There was no significant difference between cocopeat: perlite, perlite, rock wool, and NFT systems. Also, the lowest amount of necrotic leaves was found in the vermiculite culture medium, which did not have a significant difference with vermiculite: perlite culture medium. Low levels of leaf necrosis in these treatments indicate the optimal absorption of nutrients and the proper growth of plantlets in these culture media. The results showed that plantlets cultivated in the vermiculite and vermiculite: perlite flowered more quickly than other culture media and also produced more flowers. Plantlets grown in the rock wool medium did not show the desirable performance, which is due to drought stress. Besides, the use of cocopeat in the culture medium did not have a beneficial effect on plants. Measuring the initial electrical conductivity in the cocopeat culture medium also indicates a high EC concentration in this culture medium, which could affect the growth parameters of the plant and lead to poor vegetative growth of plantlets. Since Gerbera plant has bulky roots, the roots of this plant cannot be developed well in the NFT system, so the use of the NFT system is not suitable for Gerbera cultivation. The best performance of plant samples was obtained from vermiculite culture media, but since there were no significant differences between vermiculite and vermiculite: perlite, so to reduce production costs, the use of vermiculite: perlite culture medium in the closed system is recommended for the cultivation of Gerbera plant.

Since Gerbera plant has bulky roots, the roots of this plant cannot be developed well in the NFT system, so the use of the NFT system is not suitable for Gerbera cultivation. The best performance of plant samples was obtained from vermiculite culture media, but since there were no significant differences between vermiculite and vermiculite: perlite, so to reduce production costs, the use of vermiculite: perlite culture medium in the closed system is recommended for the cultivation of Gerbera plant.