Phenolic-nitrogen interactions in eelgrass, Zostera marina L.: possible implications for disease resistance

Experiments with eelgrass, Zostera marina L., transplanted into running seawater mesocosms with either a mud or sand substratum indicated that leaf nitrogen and phenolic contents were inversely related. A caffeic acid ester accounted for ∼ 50% of the phenolic content; sulfated flavones made up most of the remainder. Plants with a low phenolic content grown in mud suffered complete mortality from wasting disease, while plants with a high phenolic content in sand were still growing well when the experiment was terminated.