physiological and morphological response of polianthes tuberosa to the treatment of bulbs with plant extracts

Objective: the growing application of chemical compounds to combat pests and plant diseases has led to significant environmental contamination. employing plant compounds, such as plant extracts and essential oils, as alternatives to chemical compounds, can have a positive impact on reducing environmental pollution. tuberose (polianthes tuberosa) is a significant tropical and semi-tropical ornamental plant commercially cultivated for its cut flowers and the extraction of essential oil from its aromatic blossoms. fusarium and alternaria are the prevailing pathogens of tuberose. this research aimed to explore the effects of peppermint, savory, and thyme extracts on important traits of tuberose, as well as their efficacy in inhibiting the growth of fusarium proliferatum and alternaria alternata, as potential replacements for chemical fungicides.methods: the extracts of mentha piperita, zataria multiflora, and satureja hortensis at three rates of 12%, 25%, and 50% (v/v), were applied on tuberose plants by immersion. mancozeb fungicide at a rate of 2 g/l, was used as the control. the fungus cultivation and the experiment about the plant extracts were conducted at a laboratory in gorgan, iran. the experiment was carried out in the form of a completely randomized design with three replications. the measured traits were shoot fresh weight, floret number, floret diameter, stem length, stem diameter, spike length, leaf number, leaf area, bulb number, time to flower emergence, commencing of growth, vase life, and catalase (cat) and peroxidase (pod) enzyme activities.results: the comparison of the means indicated that the highest number of florets, floret diameter, shoot fresh weight, and pod was observed in the treatment of savory extract (12 ml/l). the highest leaf number, stem length, and cat activity were associated with the treatment of peppermint extract (12 ml/l). also, the lowest growth rates of f. proliferatum and a. alternata were obtained from the thyme extract (50 ml/l).conclusion: overall, it was found that the plant extracts utilized in this study can serve as viable alternatives for disinfecting tuberose bulbs before planting. however, the results for most evaluated characteristics implied that these substances should be applied in lower concentrations. although the extracts adversely affected the quantity of bulbs, which needs further investigation, the application of plant compounds can be deemed a reasonable approach given the numerous harmful effects of chemical pesticides. it is also recommended to explore the efficacy of other extracts in disinfecting tuberose bulbs.