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báo cáo khoa học: "Citramalic acid and salicylic acid in sugar beet root exudates solubilize soil phosphorus"
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Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Citramalic acid and salicylic acid in sugar beet root exudates solubilize soil phosphorus | Khorassani et al. BMC Plant Biology 2011 11 121 http www.biomedcentral.com 1471 -2229 11 121 BMC Plant Biology RESEARCH ARTICLE Open Access Citramalic acid and salicylic acid in sugar beet root exudates solubilize soil phosphorus 1.2 3 3 1 3 1 Reza Khorassani 1 Ursula Hettwer Astrid Ratzinger Bernd Steingrobe Petr Karlovsky and Norbert Claassen Abstract Background In soils with a low phosphorus P supply sugar beet is known to intake more P than other species such as maize wheat or groundnut. We hypothesized that organic compounds exuded by sugar beet roots solubilize soil P and that this exudation is stimulated by P starvation. Results Root exudates were collected from plants grown in hydroponics under low- and high-P availability. Exudate components were separated by HPLC ionized by electrospray and detected by mass spectrometry in the range of mass-to-charge ratio m z from 100 to 1000. Eight mass spectrometric signals were enhanced at least 5-fold by low P availability at all harvest times. Among these signals negative ions with an m z of 137 and 147 were shown to originate from salicylic acid and citramalic acid. The ability of both compounds to mobilize soil P was demonstrated by incubation of pure substances with Oxisol soil fertilized with calcium phosphate. Conclusions Root exudates of sugar beet contain salicylic acid and citramalic acid the latter of which has rarely been detected in plants so far. Both metabolites solubilize soil P and their exudation by roots is stimulated by P deficiency. These results provide the first assignment of a biological function to citramalic acid of plant origin. Background Sugar beet and wheat are similar in their phosphorus P efficiency with regard to shoot production 1 but they appear to use different mechanisms to overcome low availability of soil P. Wheat has a large root system that compensates for low P influx when P availability is low whereas sugar beet is able to achieve high P influx despite low P availability in .