Seyedeh Tina Mousavi Kani, Davoud Kartoolinejad, Zohreh Bahrami, Ali Asghar Zolfaghari, Elahe Nikouee,
Volume 9, Issue 1 ((Spring and Summer) 2022)
Abstract
Extended Abstract
Introduction: Nowadays, due to land use change and destruction of natural resources induced by human activities, attention to desertification has immensely become widespread. One of the most important species for biological rehabilitation of desert areas on a large scale is the hawthorn plant. Hawthorn is a plant belonging to the family Amaranthaceae, the two species of which are called white saxaul (Haloxylon persicum Bunge ex Boissier & Buhse) and black saxaul (Haloxylon aphyllum (Minkw.) Iljin) are more notorious and widespread in Iran. These plants own extensive root systems and stabilize running sands. The aim of this study was to investigate the effect of mesoporous titanium dioxide nanoparticles on germination traits of black saxaul seeds under drought stress, as an important species in desert areas.
Materials and Methods: The experiment was performed as a factorial experiment in a completely randomized design with 3 replications. Experimental treatments included five titanium nano dioxides with concentrations of 0, 25, 50, 100 and 200 mg / l and six drought stress levels including 0, -4, -8, -12, -16 and -20 bar. After nanopriming, black saxaul seeds were subjected to drought stress for 15 days in a germinator at a temperature of 20 °C with four replications. After germination, in each of the treatments, germination percentage (GP), germination rate (GS), mean germination time (MGT) and seed vigor index (VI) were calculated.
Results: The results of two-way ANOVA and mean comparison of germination indices showed that the highest germination percentage (74%) belonged to the zero level of stress treatment with a concentration of 200 mg/l and the lowest one (3%) belonged to -20 bar treatment with 25 and 200 mg/l nano-titanium dioxide. With increasing drought stress intensity from zero to -20 bar level, germination rate decreased from 7.01 to 0.43 seeds per day. The highest amount of seed vigor index at zero drought level belonged to the treatment of 200 mg/l concentration of nano-titanium, with a rate of 325.77.
Conclusion: The results showed that germination indices and initial growth of black saxaul seeds decreased in all primed and unprimed treatments with increasing drought stress, and nanopriming with titanium dioxide had a positive effect on seed germination traits.
Highlights:
1- Seed priming using mesoporous nano-titanium dioxide improved the germination percentage of black saxaul seeds under drought stress.
2- The concentration of 200 mg/l of mesoporous nano titanium dioxide revealed a better effect on seed germination index, mean germination time, germination rate and percentage
3- Seed nano priming using titanium dioxide did not have much effect on the growth characteristics of black saxaul seedlings at higher levels of drought stress.
Zahra Zare Mahmoudabad, Roghayeh Zolfaghari, Payam Fayyaz,
Volume 12, Issue 2 ((Autumn & Winter) 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.
