Zahra Zare Mahmoudabad, Roghayeh Zolfaghari, Payam Fayyaz,
Volume 12, Issue 2 (3-2026)
Abstract
Objective: The oak forests of the Zagros region, as a valuable ecosystem, have experienced extensive degradation in recent years due to various factors, including climate change and human activities. The rehabilitation of these forests requires the production of resilient, high-quality saplings. This study aimed to investigate the effect of the fungus Trichoderma harzianum as a biological growth-promoting agent on the seed emergence and early growth of Quercus brantii seedlings in order to evaluate its efficacy in improving the growth and physiological parameters of this species under both greenhouse and natural forest conditions.
Method: Seeds collected from mother trees in the Yasouj forest site were planted in pots (under greenhouse conditions) and pits (in the forest), and a biological treatment using a Trichoderma fungal solution was applied to the seeds. Subsequently, emergence, growth, and physiological traits of the seedlings were measured and compared throughout the growing season.
Results: The results showed that under greenhouse conditions, the Trichoderma treatment significantly increased the seed emergence percentage, photosystem performance index (PI), and chlorophyll index compared with the control group. However, no significant differences were observed in other growth traits, such as height, leaf number, and the dry and fresh weights of plant organs. In contrast, under natural forest conditions, the emergence percentage in the control group was significantly higher than in the Trichoderma treatment, and other growth traits showed no significant differences between the two groups. Furthermore, a significant positive correlation was observed between physiological indices (such as performance index and chlorophyll) and some growth traits (such as root length and stem dry weight) under greenhouse conditions.
Conclusions: The findings of this study indicate that the effect of Trichoderma fungus on Persian oak is complex and depends on environmental conditions (as evidenced by the significant difference between greenhouse and natural forest field conditions) and the host plant species (in comparison with previous studies on other plants). Therefore, conducting long-term field studies with different Trichoderma isolates and concentrations is recommended to achieve more practical results in Zagros restoration programs.
Highlights:
- First study on the effect of Trichoderma harzianum on Persian oak (Quercus brantii), addressing a key knowledge gap in Zagros forest restoration.
- Simultaneous greenhouse and field trials revealed environment-dependent effects of Trichoderma, confirming the necessity of field experiments.
- Limited positive and negative effects challenge the belief that Trichoderma is always a growth promoter, emphasizing species-specific and native approaches.
