Variability of Chlorophyll and Carotenoid Content in the Forest Grass Melica uniflora Retz.

Chlorophylls and carotenoids are key plant metabolites involved in photosynthesis, stress responses, and antioxidant activity. This study aimed to examine intrapopulation variability in Melica uniflora Retz. (wood melick), focusing on chlorophyll and carotenoid content in relation to the developmental stage and environmental conditions. Research was carried out over three consecutive years (2021–2023) in the Ślęża Massif near Sobótka, Lower Silesia, Poland. Leaf blades samples were collected annually from ten natural forest sites at two time points: summer (July) and autumn (October), and analyzed for chlorophyll a, chlorophyll b, and total carotenoids using spectrophotometry. Statistical analyses, including ANOVA, were used to assess the effects of year, harvest time, and site on pigment concentrations. The average (±SD) pigment content in M. uniflora was 1.44 ± 0.73 mg∙g−1 DM for chlorophyll a, 0.67 ± 0.40 mg∙g−1 DM for chlorophyll b, and 0.46 ± 0.28 mg∙g−1 DM for total carotenoids. Among the factors studied, year and developmental stage had the strongest statistically significant influence on chlorophyll and carotenoid levels, while site-specific differences contributed to intrapopulation variability to a lesser extent (p < 0.001). Interestingly, the first year of the study showed higher average pigment levels across both harvest times. Summer-collected plants had higher concentrations of all pigments than those collected in autumn. Differences among sites further indicated intrapopulation variability within this species. These findings provide new insights into the natural variability of photosynthetic metabolites in forest grasses and may serve as a reference for studies on the adaptive and biochemical responses of woodland plant species to environmental factors.