Effect of Trichoderma Isolates on Morphophysiological Changes of Polianthes Tuberose under Drought Stress

In order to evaluate the effect of different Trichoderma isolates on reducing the effects of drought stress on Polianthes tuberose, two factorial experiments were carried out based on completely randomized design with three replications. The first factor in the first experiment was bi isolate, and in the second experiment was isolate 65 of Trichoderma harzianum, each at three levels (0, 10, 20% v/v) and the second factor was three levels of drought stress (25, 50, 100% of pot capacity). Results showed that both isolates increased fresh and dry weight of the biomass and root dry weight of Polianthes tuberose plant under stress conditions. The fresh weight of the biomass was increased by 20% in 25% stress by bi isolate and 29.5% by isolate 65, indicating that the growth of Polianthes tuberose in the presence of Trichoderma fungus increased. Proline content was increased by 40 and 32% by isolates bi and 65 in 25% stress compared to 100% pot capacity. The relative water content and leaf area were increased by applying different levels of the two fungi with increasing stress levels. The leaf area in the 25% stress and 20% fungus treatment were increased by 26 and 24%, respectively, in isolates bi and 65, compared to fungus-free pots. It seems that the isolates bi and 65 of Trichoderma harzianum have different effects under drought stress conditions. In terms of stress, 100% pot capacity and bi-isolate treatment, the root dry weight, fresh and dry weight of biomass, relative water content and leaf green area were more than the same traits in isolate 65 treatment.