Document Type : Research Paper - Seed Sciences
Authors
1 Department of Horticultural Sciences, Islamic Azad University, Garmsar, Iran
2 Department of Horticultural Sciences, Garmsar Branch, Islamic Azad University, Garmsar, Iran .
Abstract
Introduction
Papaya (Carica papaya) is a tropical fruit that leaves, fruits, seeds and roots has many medicinal and edible uses. Choosing the appropriate planting medium is one of the important goals in improving seedling growth of fruit trees, because by improving the physical and chemical properties, it causes better absorption of nutrients and improves plant growth. Also, performing aerial root pruning to produce seedlings with branched and strong root systems is one of the effective factors in growing plants.
Materials and methods
To study the effect of different culture media and aerial root pruning on the growth of Papaya (Carica papaya), an experiment was conducted in the form of a completely randomized statistical design with three replications and two factors of planting media (cocopeat 100% , peat mass 100% , and cocopeat 70% + perlite 30% , peat moss 70% + perlite 30%) and performing or not performing aerial root pruning was implemented in the greenhouse. The seeds were sown in October in the culture trays containing the desired planting beds, and horizontal cuts were made in the walls of the culture tray cavities to perform aerial pruning of the roots in the desired treatments. Sampling was done 50 days after planting the seeds and some morphologic, physiologic and biochemical traits include fresh and dry weight of seedlings, root length, seedling height, internode length, node number, leaf area, total chlorophyll, peroxidase, catalase and superoxide dismutase activity were analyzed.
Results and Discussion
The results showed that the treatments had a significant effect on the assessed traits so that the highest fresh and dry weight of seedlings (1.69 - 0.66 g), root length (17.66 cm), seedling height (7.92 cm), internode length (8.61 mm) and node number (4.67) were observed in 70% peat moss + 30% perlite and no aerial root pruning. The maximum leaf area (9.14 cm3) and total chlorophyll (1.69 mg g-1 FW) content were obtained in the 100% peat moss planting bed treatment and no aerial root pruning and the 70% peat moss + 30 % perlite treatment and root aerial pruning. The highest activity of peroxidase (37.60 U enzyme-1 FW), catalase (7.60 U enzyme-1 FW) and superoxide dismutase (16.08 U enzyme-1 FW) enzymes was also in 100 % peat moss treatment and root aerial pruning.
Conclusion
In general, the results of this research showed that the combination of two organic and inorganic substrates, peat mass 70% and perlite 30%, showed the best effect on vegetative characteristics and total chlorophyll content in papaya. Also, the highest activity of peroxidase, catalase and superoxide dismutase enzymes was observed in 100% peat moss bed. Root aerial pruning also decreased the evaluated growth characteristics and increased the total chlorophyll content and activity of peroxidase, catalase and superoxide dismutase enzymes. According to the results, Different culture media have different physical and chemical characteristics that can affect plant growth, in this research it is recommended to papaya seeds in 70% peat moss and 30% perlite and not to perform aerial root pruning to produce this product.
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