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Improvement of vegetative growth and morpho-physiological characteristics of Taxus baccata through the use of gibberellic acid and humic acid
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Meisam Tahmasb pour karimi   , Mahnaz Karimi * , Hossein Moradi |
| Sari Agricultural Sciences and Natural Resources University |
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Abstract: (46 Views) |
The yew tree (Taxus baccata L.) is considered one of Iran’s valuable plant resources and, due to excessive harvesting and destruction of its natural habitats, is at risk of destruction and extinction. This tree can be used as a single tree or as a hedge in urban green spaces. The growth rate of plants is an important factor when selecting them for planting in green spaces. The yew tree is classified as a slow-growing plant, which limits its use in urban landscaping. To investigate the effect of gibberellic acid and humic acid on improving vegetative growth and morpho-physiological characteristics of yew seedlings, a factorial experiment was conducted in a completely randomized design with three replications. The first factor was gibberellic acid at three levels (0, 50, and 100 mg g-1) applied as foliar spray, and the second factor was humic acid (0 and 1000 mg g-1) applied through root irrigation .The results showed statistically significant differences among the treatments regarding the traits studied in yew seedlings. The highest number of lateral buds was observed in treatments with humic acid, gibberellic acid 100 mg g-1combined with humic acid, and gibberellic acid 100 mg g-1without humic acid. The greatest shoot length growth was found in humic acid treatments without gibberellic acid and gibberellic acid 50 mg g-1 treatment without humic acid. The highest chlorophyll content was observed in plants treated with gibberellic acid 50 mg g-1, showing an 11% increase compared to the control. The highest flavonoid content was in the gibberellic acid 50 mg g-1combined with humic acid treatment, and the highest antioxidant content was recorded in gibberellic acid treatments of 50 and 100 mg g-1 without humic acid. Analysis of leaf nutrient content showed that phosphorus levels increased in all treatments where humic acid was applied. Application of gibberellic acid and humic acid treatments, compared to untreated plants, improved growth, especially by increasing the number of lateral buds and branches. Moreover, in addition to improving vegetative growth, physiological traits and internal nitrogen and phosphorus contents of the plants showed significant increases compared to the control. Flavonoid and antioxidant compounds also significantly increased compared to the control plants. Therefore, the use of gibberellic acid and humic acid, either alone or in combination, is recommended to improve vegetative growth and morpho-physiological traits of yew.
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| Keywords: Chlorophyll, gymnosperms, hormone, organic substances |
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Type of Study: Applicable |
Subject:
Special
Received: 2025/04/15 | Accepted: 2025/09/2 | Published: 2025/12/2
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