Zinc addition and mowing alter the timing and duration of reproductive phenology in dominant plants of a meadow steppe

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Abstract Plant phenology, while genetically determined, is highly responsive to environmental drivers such as soil nutrient availability and disturbance. As an essential micronutrient, zinc (Zn) plays a critical role in plant development by regulating key processes including RNA polymerase function, auxin synthesis and antioxidant defence. We investigated how Zn addition and mowing disturbance influence the reproductive phenology of six dominant plants in an Inner Mongolian meadow steppe. Over 3 years, we applied Zn (0.5 g m −2 year −1 ) and simulated foraging via mowing in a factorial experiment. Our results revealed strong, yet species‐specific, responses. Zn addition advanced reproductive timing in grasses (e.g. Leymus chinensis shortened its flowering by 6 days and prolonged fruiting by 8 days) but delayed all reproductive phases in forbs (e.g. by 4–10 days in Thalictrum petaloideum and 16–25 days in Potentilla bifurca ). The phenology of the late‐flowering forb Serratula centauroides and the early‐flowering sedge Carex duriuscula was largely unaffected by Zn addition. Mowing generally delayed or shortened reproductive phases in grasses and forbs but advanced them in S. centauroides and C. duriuscula . Causal analyses indicated that Zn effects were mediated through changes in superoxide dismutase activity, soluble sugar concentration and chlorophyll content, whereas mowing effects were primarily driven by alterations in soil water content and light conditions. Thus, the interactive effects of Zn and mowing arise from complex interplay between carbon metabolism, antioxidant defence, photosynthesis and water use. Synthesis . These species‐specific phenological shifts to soil Zn availability and disturbance suggest that changes in these drivers could potentially alter plant community structure by differentially affecting the reproductive success of functional groups. Read the free Plain Language Summary for this article on the Journal blog.

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