The influence of manganese on switchgrass and pearl millet

Manganese is an essential micronutrient and plays key roles in photo­synthetic processes, including in NAD-malic enzyme (NAD-ME)-type C4 plants, as an activator of NAD-ME. Previous studies have indicated a benefit of high Mn availability during early growth of NAD-ME C₄ plants. However, little is known about Mn requirements of switchgrass.

In a recent article in Crop Science, researchers reported on the effects of a range of Mn availability on switchgrass, and in one of the three years, also compared the response of switchgrass to that of pearl millet, another NAD-ME C₄ plant.

Plants were grown under field conditions in pots filled with either washed sand, vermiculite, or perlite and fertilized with nutrient solutions ranging in [Mn] from 0 to 200 μM.

The researchers found that shoot Mn was highly responsive to increasing Mn in the nutrient solution. However, an increase in seasonal biomass production in response to Mn addition was only observed in perlite for pearl millet and the upland switchgrass ecotype but not the lowland ecotype.

In contrast to previous research, biomass production did not increase in response to elevated Mn availability, indicating that NAD-ME plants may not require greater Mn availability than other C₄ subtypes or C₃ plants.