Tradeoffs between isoprene emission, carbon gain and water use among different genera of Arundineae

There is a growing interest for the application of biofuels in different parts of the world. It is assumed that the cultivation land for biofuel crops will reach up to 752Mha in 2050. However, a large number of biofuel crops are emitting isoprene, which is highly reactive VOCs and affects the oxidative capacity of the atmosphere. In addition, the large-scale cultivation of biofuel crops will affect the water and nutrient resources of land. Therefore, the evaluation of biofuel crops with regard to their environmental effects and searching for new crops with less environmental impacts is highly beneficial. During this work, we screened 6 different species of Arundineae, a tribe from Poaceae, in terms of their photosynthesis, isoprene emission, water use efficiency (WUE), chlorophyll fluorescence, leaf anatomy and biomass development. Based on our results, A.donax showed the highest biomass increase and WUE and lowest fraction of assimilated carbon lost as isoprene, which highlights its capacity as a biofuel crop with low negative environmental effects compared with other genera of the Arundineae. The investigated species had different capacities for isoprene emission and there was a positive correlation between isoprene emission and photosynthesis within the tribe. Non-isoprene emitter species had much higher non-photochemical quenching (NPQ) compared with isoprene emitters, which confirms the photo-protective role of isoprene. There were simillarities in leaf anatomy of some species while the chloroplast shape was specificit for each species