Cell wall for higher growth rates in diatoms. In brown algae, phlorotannins may be a constituent of the cell walls. The group Oomycetes, also known as water molds, are saprotrophic plant pathogens like fungi. Until recently they were widely believed to be fungi, but structural and molecular evidence has led to their reclassification as heterokonts, related to autotrophic brown algae and diatoms. Unlike fungi, oomycetes typically possess cell walls of cellulose and glucans rather than chitin, although some genera (such as "Achlya" and "Saprolegnia") do have chitin in their walls. The fraction of cellulose in the walls is no more than 4
Phospholipid-derived fatty acids are not significantly present in routine PLFA sample preparation which is designed to cleave ester-linked fatty acids. Arbuscular mycorrhizae fungi (AMF) penetrate the walls of cortical cells of about 80% of all vascular plant families, generating a symbiotic relationship. The fungi form membrane structures adjacent to the plant cell membrane allowing exchange of phosphorus, nitrogen compounds and minerals from the fungus and the plant provides the fungus primarily with photosynthesis-derived sugars. As the AMF are obligate symbiotic fungi, they are not free-living in the soil. The AMF hyphae in the root form lipid materials which then are transported to the