نوع مقاله : پژوهشی
نویسندگان
1 دانشگاه علوم کشاورزی و منابع طبیعی ساری - گروه باغبانی
2 دانشیار گروه علوم و مهندسی باغبانی، دانشکده علوم زراعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری، ایران
3 دانشآموخته کارشناسی ارشد گیاهان دارویی، گروه علوم و مهندسی باغبانی، دانشکده علوم زراعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری،
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and objectives: The global trend toward using medicinal plants and natural compounds, also the growing domestic interest in this field, the need for basic and applied research on basil (Ocimum basilicum L.), a warm-season medicinal-vegetable plant, has increased. Basil faces photosynthetic challenges under low-light conditions in the cold season, as light affects chlorophyll and carotenoid production, stomatal opening and closing, and growth. LED lamps, due to their small size, high durability, long lifespan, and ability to provide specific wavelengths (e.g., red-to-blue ratios of 2:1 or 3:1), are superior to traditional light sources and enhance growth, photosynthetic efficiency, and phenolic compounds; particularly, blue light increases carotenoid accumulation. To cope with reactive oxygen species (ROS) under stress, plants utilize antioxidant systems (enzymatic and non-enzymatic) such as ascorbic acid. The combined or separate application of salicylic acid and ascorbic acid under stress conditions increases chlorophyll and carotenoid levels, reduces antioxidant enzyme activity, and leads to improved growth and stress resistance in basil. The aim of this study is to investigate the effects of these factors on the photosynthetic and antioxidant characteristics of basil in a controlled environment.
Materials and methods: To investigate the responses of photosynthetic pigments in basil to various light treatments combined with ascorbic acid foliar application, a pot experiment was conducted in 2023 using a split-plot design based on a randomized complete block design with three replications. The main factor consisted of different LED light spectra with three blue-to-red light ratios (BBBR, BBRR, BRRR) and full-spectrum light (FFFF). The sub-factor included the application of ascorbic acid at two levels (applied and non-applied). The traits evaluated in this experiment included chlorophyll index, chlorophyll a and b, carotenoids, and photosynthetic parameters such as minimum, maximum, and variable fluorescence.
Results: The results indicated that the application of ascorbic acid combined with red-blue light (50:50) led to an approximately 5% increase in the chlorophyll index. Additionally, the combination of blue-red light (75:25) with ascorbic acid resulted in a 12% increase in chlorophyll a compared to full-spectrum light. Foliar application of ascorbic acid under the red-blue light spectrum (75:25) caused a 53% increase in chlorophyll b. Furthermore, the red-blue light treatment (50:50) combined with ascorbic acid increased carotenoid content by 17% compared to the control. Moreover, the application of ascorbic acid under the red-blue light (75:25) significantly enhanced the values of minimum, maximum, and variable fluorescence.
Conclusion: Overall, the exogenous application of ascorbic acid combined with an appropriate red-blue light spectrum can be recommended as an effective and economical strategy to improve photosynthetic indices under low-light conditions.
کلیدواژهها [English]
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