Response of chlorophyll a fluorescence, chlorophyll content, and biomass to dust accumulation stress in the medicinal plant, Plantago lanceolata L. Mehran Alavi1*, Mozafar Sharifi1 and Naser Karimi2*

In arid and semi-arid areas of the world, excessive mineral aerosol carried by air parcels is a common climatic incident with well-known environmental side effects. In this study, the role of sand-dust accumulation was investigated on various aspects of photosynthetic yield of Plantago lanceolata including chlorophyll (Chl) a, b, effective quantum yield of PSII photosystem (ФPSII), maximal quantum yield of PSII photosystem (Fv/Fm), electron transport rate (ETR), and biomass. P. lanceolata was exposed to a gradient of dust concentrations (0.5 (T1), 1 (T2), and 1.5 g/m3 (T3)) in a dust chamber for a period of 60 days. Results of this experiment indicated that chlorophyll content of shoot is negatively correlated with the intensity of the dust exposure. Exposure of plant in T1, T2 and T3 treatments of dust caused a reduction in ΔF/Fm´ at 4%, 21%, and 26%, respectively. At the same time a reduction of 19%, 22%, and 46% in three treatments was observed for ETR. However, dust accumulation on the plant had not a significant reduction in Fv/Fm. Chlorophyll content had a significant reduction in the chlorophyll b. Also, the amounts of reduction in shoot dry mass of T1, T2, and T3 treatments were 26%, 29%, and 32%, respectively, as compared with their respective control.