Abstract text: Polysaccharides are major components of the plant cell wall. Some of them, namely the pectins, possess a very complicated and highly charged structure. Among the pectic polysaccharides, one subgroup, the apiogalacturonans (AGAs), are only rarely described throughout the whole green lineage. Up to now, AGAs are only known from duckweeds and seagrasses. Both groups are neither monophyletic nor closely related, but belong to the order of Alismatales. This fact pinpoints a shared evolutionary trajectory and highlights the need of a systematized analysis throughout that order to infer influence factors, which lead to AGAs occurrence. We therefore compiled a broad dataset of terrestrial and aquatic alismatid species for screening of pectin characteristics such as degree of esterification by NMR, rhamnogalacturonan-I (RG-I) content, RG-II contents and its monomer/dimer ratios. We saw a negative correlation of detectable RG-II presence and AGA occurrence in seagrasses which supported earlier results on duckweed pectins. Further experimental results hinted towards a boron storage or fixation strategy by utilizing apiose residues.