Exploring Rubisco's Performance in Early Land Plants

You know how Rubisco is crucial for photosynthesis? Well, scientists took a look at how this enzyme operates in some early land plants like conifers and lycopods. They found that under conditions where CO 2 is plentiful, Rubisco's carboxylase activity in these plants was similar to that in modern C 3 crops. But when CO 2 is scarce, their Rubisco didn't perform as well. This suggests that these early plants might not be as efficient at using CO2 as their modern counterparts. Interestingly, even though these plants have less efficient Rubisco, they don't seem to have more of it to make up for the difference. It's like they haven't evolved to be super-efficient at this critical step in photosynthesis. Why might this be? Scientists think it could be due to how Rubisco has evolved over time.