engleski

Seasonal variations of photosynthetic efficiency in invasive species Amorpha fruticosa L.

Indigobush (Amorpha fruticosa L.) is widely distributed invasive species native to North America. It was deliberately introduced to Europe primarily to prevent soil erosion, but recently it is often planted for decoration, honey production and biomass energy production. Uncontrolled expansion of Indigobush represents a significant threat to native species due to its rapid growth and reproduction as well as its allelopathic activity that negatively affects nearby vegetation. The aim of this study was to analyze and compare changes in photosynthetic performance of Indigobush and accompanying woody species (Quercus robur L. and Alnus glutinosa (L.) Gaertn.). Therefore, photosynthetic performance was analyzed by measuring direct chlorophyll fluorescence twice during the vegetation season, in May and July. Indigobush seedlings grow in the Pokupsko basin forest complex near Karlovac (Croatia) in stands of varying size and age. For this investigation, three locations were chosen that were about the same size and age. Our results showed that performance index (PIabs) in Indigobush increased significantly in July at all three locations compared to both accompanying species. Moreover, more enhanced electron transport per reaction center (ET0/RC), the efficiency that an electron moves further than primary electron acceptor QA− (ET0/ TR0), maximum quantum yield of primary photochemistry (TR0/ABS) as well as quantum yield of electron transport (ET0/ABS) followed by an increase in structure-function index (SFIabs) in Indigobush was observed in July. Our results suggested that Indigobush was able to utilize absorbedlight energy more efficiently than accompanying native species.

Indigobush, invasive alien species, performance index, structure-function index

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