Chemical Composition of Australian Mangroves II. Low Molecular Weight Carbohydrates

Low molecular weight carbohydrates (LMWC) occurring in both young and old leaves of 22 mangrove species from Northern Queensland (Australia) were identified using gas liquid and gas capillary chromatography. The cyclitol, pinitol, was the most prevalent compound in all members of the Rhizophoraceae and in the mangrove fern Acrostichum speciosum. In addition, Aegialitis annulata stored chiro-inositol. Another cyclitol, quebrachitol, occurred in Excoecaria agallocha. Mannitol, a polyol, was dominating in Aegiceras corniculatum, Lumnitzera littorea, Lumnitzera racemosa, Sonneratia alba and Scyphiphora hydrophylacea. The sugars sucrose, glucose, and fructose were not generally stored in high concentrations (except Xylocarpus granatum, 300 mol · m⁻³ plant water). Those species which contained no cyclitols or mannitol were low in their LMWC content. LMWC concentrations were higher in young leaves than in old ones in nearly all species under investigation.

Polyols and cyclitols may have taxonomically associated distributions and may play a role in osmotic adjustment.