There are some plants (e.g., Indian pipe, orchids) that do not have chlorophyll yet they are connected to the mycorrhizae web. What would you suspect their relationship to be?

Answer 1

Most plants harvest energy from the sun through photosynthesis using a green pigment called chlorophyll. Plants that do not have chlorophyll are less likely to be conducting photosynthesis. If these plants are connected to the mycorrhizae web and do not have any chlorophyll, I would expect that these plants are getting their energy from the web and not through photosynthesis. In other words, they are likely stealing energy from other photosynthetic plants through this web instead of harvesting their own from the sun. This would suggest that these plants are benefitting from their interaction with the web without (we assume) providing any benefits in return. In fact, since these plants are "stealing" energy from the web, and the photosynthetic plants are therefore losing energy, the photosynthetic plants are actually harmed by this reaction. And what do we call an interaction between two organisms in which one benefits and the other is harmed? Parasitism! I suspect that this relationship is parasitic.