The researchers studied how different plant species respond to changes in humidity levels. They measured how open the plants' stomata (tiny pores on leaves) were when the air was dry. They found that some plants, like Rhodomyrtus tomentusa and Schima superba, had more open stomata when it was dry, while others, like Ardisia quinquegone, kept their stomata more closed. They also looked at a tree species, Acacia mangium, and found that it was good at adjusting its stomata to dry conditions, similar to Schima superba. This research helps us understand how different plants cope with dry weather and regulate their water levels.