Novel compound specified in dune reed (Phragmites communis Trin.) and its possible role as a protectant on the chloroplasts under stress

It is well documented that environmental or abiotic stresses such as drought, high or low temperature as well as high salinity have a common effect on plant water status, accompanied by lower photosynthetic rate([1,2]). On the other hand, the plant often accumulates some metabolites in cell to intensify its anti-stress capacity([3,4]). These stress-induced metabolites are usually nitrogen-containing compounds (proline, quaternary amino compound and polyamines) and hydroxyl compounds (sucrose, polyols, and oligosaccharides)([5]). And they do not interfere with or have little negative effect on the normal biochemical metabolic network([6]). Instead, they play a multiple role in adjusting cell osmotic potential and maintaining the integration of proteins and biomembrane under stresses. The contribution of accumulated solutes to wild plants is usually estimated from the information deduced from the accumulation in multitudinous lab systems. And it would make much sense by the investigation on the compatible solutes accumulation in wild plants that exhibit excellent tolerance to natural abiotic stresses and their relationship to the adaptation of the owner to the inimical environment. Reed plants are hydrophilous of Graminea, whose typical habitat is shallow fresh and brackish water area of the swamps, riversides and lakeside. However, they can adapt themselves to diverse and adverse terrestrial habitats and have evolved various ecotypes which exhibit stable genetic differences([7-9]). There are swamp reed and three terrestrial reed ecotypes growing in the desert regions of northwest China (approximately 3.3X10(5) ha). We have found some stable variations occurring within their morphological and physiological characteristics in response to drought, high temperature and saline habitats([10]). These stable reed ecotypes are ideal model system for ecophysiological research into tolerance or resistance to different environmental stresses. This note describes a typical novel compatible solute, which only exists in leaves of dune reed and shows some possible physiological effect in protecting the plant against high desert temperature.