Document Type : Original Article

Authors

• Bahareh Kashefi ¹
• Faeze Bahri ²

¹ Assistance Prof. College of Agriculture, Islamic Azad University, Damghan Branch, Damghan, Iran.

² Graduated Student, College of Agriculture, Islamic Azad University, Damghan Branch, Damghan, Iran.

Abstract

Introduction
Drought stress is one of most common Non-biological tensions that it limits plant growth in arid and semi-arid. In arid and semi-arid regions, water deficiency is one of the factors limiting the growth of plants. Access to cultivars that can grow and develop high crop production under drought stress is very important. Hexaconazole in Triazole mixtures are new types of chemicals that with prevention kaoreen oxidase activity and gibberellin biosynthesis leads to vegetative growth reduction and generative growth increase .These compositions also are causes to raising splits numbers and reducing the growth. Malva sylvestris is a valuable medicinal plants, from the Malvasia family, is a one-year, two-year-old or seldom perennial herb.

Materials and methods
To evaluate Hexaconazole treatment effect on Malva sylvestris growth features under drought stress, an experiment was conducted in a completed randomized design as factorial in 4 replicate in the Neyshabour city. In plant phenological stage, in Four-leaf to five-leaf level water stress in witness and 50% of Field capacity and Hexaconazole treatment was applied in 3 levels with 0, 15 and 25 mg L−1 as leaf spray. The reaction of the plant was studied for about two months, then physiomorphological traits and antioxidant enzymes activity were measured. After performing the project and collecting data, statistical analysis was performed using SAS software. The mean comparison was determined by Duncan's multiple range test at a probability level of 1% and the correlation between traits was determined. Excel was also used to draw charts.

Results and discussion
the results of analysis of variance showed that the effects of drought stress and hexaconazole treatment had significant differences in most of studied traits at 1% probability level. Treatments causes to reduction stem length, root and leaf area and it increases root ratio to stem and wet and dry weight, density proline and catalase and peroxidase enzymes. It was also observed that the treatments do not effect on the number of leaves, chlorophyll a, b, and total and protein. Drought stress reduces turgor and disrupts division and prolongation of cells. Hexaconazole is an active member of the family of triasol, which has been shown to play a role in regulating plant growth. Hexaconazole has been shown to cause morphological and physiological changes in plants. Physiological effects of triazoles can be attributed to increasing chlorophyll content per unit area, reducing respiratory activity, increasing antioxidant activity and increasing plant resistance to stress. As the results of the study indicated, hexaconazole is effective in modulating the effect of drought stress on Malva sylvestris plant.

Conclusion
The results of this study showed that hexaconazole treatment decreased with growth leaf area and Number of leaves, increase shoot/ root growth rate, vegetative growth of shoot and root, fresh and dry weight, chlorophyll, soluble sugars, peroxidase and catalase enzymes and proline concentration, the plant's defense mechanism improves to drought stress. Also, It has been determined that plant growth regulator such as hexaconazole can be effective in the development of growth and the improvement of some plant characteristics and reduce plant stress.

Keywords

• Abiotic stresses
• Growth characteristics
• Malva sylvestris
• Spray solution
• Triazole