Document Type

Research Poster

Publication Date



The purpose of this investigation was to provide an explanation into how the invasive species Pennisetium setaceum, Fountain Grass, is able to outcompete the native California grassland species Stipa pulchra, Purple Needle Grass. We used a light adapted and a dark adapted fluorometer to measure the photosynthetic radiation (PAR), leaf temperature, alpha (α), light adapted fluorescence (Fv’/Fm’), dark adapted fluorescence (Fv/Fm), and the electron transport rate (ETR) on young Fountain Grass and Purple Needlegrass. After collecting and analyzing the data, we concluded that the dark adapted fluorescence (Fv/Fm) was the only statistically significant measurement where the Fv/Fm of S. pulchra is higher than that of P. setaceum which suggests that S. pulchra’s quantum yield of photosystem II is higher and is therefore more efficient. With this result, we are able to state that Fv/Fm is not the reason why Fountain Grass outcompetes Purple Needlegrass.