DefinePK

Research Objective

To evaluate the potential role of salicylic acid in enhancing the growth and physiological performance of sunflowers under drought stress.

Methodology

A pot experiment was conducted in a greenhouse. The study involved three treatments: control (normal irrigation), drought stress (50% irrigation), and drought stress with foliar application of 250 mg L⁻¹ salicylic acid. Each treatment was replicated five times. Growth parameters (shoot length, root length, fresh shoot weight, dry shoot weight, fresh root weight, dry root weight), physiological parameters (chlorophyll content, stomatal conductance, relative water content, membrane stability index), oxidative stress markers (malondialdehyde, hydrogen peroxide), and antioxidant enzyme activities (superoxide dismutase, catalase, peroxidase) were measured. Statistical analysis was performed using SPSS, with Tukey's HSD test for mean comparisons.

Methodology Flowchart

                        graph TD
    A[Pot Experiment Setup] --> B[Impose Treatments: Control, Drought Stress, Drought Stress + SA];
    B --> C[Apply Foliar SA250 mg L⁻¹];
    C --> D[Measure Growth Parameters];
    D --> E[Measure Physiological Parameters];
    E --> F[Measure Oxidative Stress Markers];
    F --> G[Measure Antioxidant Enzyme Activity];
    G --> H[Statistical Analysis ANOVA, Tukey's HSD];
    H --> I[Interpret Results and Draw Conclusions];                    

Discussion

Drought stress significantly reduces sunflower growth and biomass due to decreased leaf area and impaired physiological processes. Salicylic acid application effectively mitigates these adverse effects by improving growth parameters, enhancing physiological functions like photosynthesis and water retention, and bolstering the plant's antioxidant defense system to combat oxidative damage.

Key Findings

Foliar application of 250 mg L⁻¹ salicylic acid significantly improved growth parameters, including shoot length (24.92%), root length (18.97%), fresh shoot weight (15.78%), dry shoot weight (24.15%), fresh root weight (21.32%), and dry root weight (26.72%) under drought stress. Physiological parameters also improved: chlorophyll content increased by 32.90%, stomatal conductance by 19.52%, relative water content by 20.84%, and membrane stability index by 41.79%. Salicylic acid mitigated oxidative damage by reducing malondialdehyde levels by 32.81% and hydrogen peroxide levels by 17.80%. Antioxidant enzyme activity increased: superoxide dismutase by 17.25%, catalase by 40.05%, and peroxidase by 10.41%.

Conclusion

Foliar application of 250 mg L⁻¹ salicylic acid is an effective strategy to enhance the growth and physiological parameters of sunflower plants under drought stress, offering a sustainable approach to mitigate the impact of water scarcity on crop production.

Fact Check

* Drought stress reduced shoot length by 30.91% compared to normal conditions.
* Salicylic acid application increased chlorophyll content by 32.90% under drought stress.
* Malondialdehyde (MDA) levels increased by 126.91% under drought stress before SA application.

Mind Map