Akademik Veri Yönetim Sistemi
II. International Conference on Chemistry and Biotechnology-EUCHEMBIOJ 2025, İstanbul, Türkiye, 5 - 07 Aralık 2025, cilt.1, ss.1, (Özet Bildiri)
Humic acids are widely used in agriculture to improve soil structure and promote plant growth; however, only a limited number of studies have focused on their overall impact on plant metabolism, and their stimulatory or delaying effects remain controversial. Studies investigating the effects of humic acid when directly applied to the leaf surface, such as tissue improvement or delay of senescence, are also very limited. This study aimed to evaluate the short-term effects of direct application of humic acid to leaf segments rather than to the soil. Barley (Hordeum vulgare L.) seedlings were grown for 15 days. Segments of 3 cm in length were cut from the first leaves, and four segments obtained from four different plants were placed in each Petri dish. A total of 6 ml of solution was added to each Petri dish. Distilled water (D.W.) was used as the control, while humic acid (HA) solutions of 0.025 ml L⁻¹ and 0.25 ml L⁻¹ were used as the experimental groups. Incubation conditions in the Petri dishes were kept constant, and the segments were incubated for 2 days. Symptoms of senescence, indicated by changes in leaf coloration, were observed. To examine tissue-level changes, fresh weight, chlorophyll and carotenoid contents, cell integrity, and antioxidant enzyme activities were analyzed. In both humic acid concentrations, senescence was delayed in leaf segments compared to the control group, and healthier tissue development was observed. A more pronounced improvement was particularly evident at the higher concentration (0.25 ml L⁻¹). This preliminary study demonstrates that humic acid can exert a direct protective effect on leaf tissues when applied to the leaf surface and may delay the senescence process. The findings suggest that humic acid may be beneficial not only in soil applications but also in the context of exogenous applications. It is recommended that future studies employ quantitative physiological and biochemical analyses to elucidate the underlying mechanisms.