Metabonomics Study on Root Exudates of Cadmium Hyperaccumulator Sedum Alfredii

A metabonomics method based on gas chromatography-mass spectrometry (GC-MS) was developed to detect the significant differences root exudates of the Cd hyperaccumulator Sedum alfredii under different treatments conditions and study the effect mechanism of toleration or accumulation of S. alfredii to heavy metal Cd. The root exudates were collected after treatment with 0 and 40 μM Cd for 4 and 8 days. The collected solution was lyophilized and dissolved with methanol. After derivatization with methoxyamine hydrochloride and N-methyl-N-trifluoroacetamide, the samples were analyzed by GC-MS. Principal component analysis (PCA) and orthogonal partial least-squares discrimination analysis (OPLS-DA) were carried out for pattern recognition and a clear separation among the different treatments was achieved. Twelve compounds which caused the separation among the different treatments were found and identified. With the change of treatments, the relative amount of these 12 compounds revealed different trends, which indicated that the Cd hyperaccumulator S. alfredii could adjust the secretion of root exudates to tolerate or accumulate the heavy metal Cd.

The root exudates secreted from the Cd hyperaccumulator Sedum alfredii under different Cd treatments conditions were determined using GC-MS, fifty-eight compounds were detected and identified. The result of PCA and OPLS-DA indicated that the root exudates samples can clearly separated among the different treatments. Twelve compounds which caused this separation were found and identified.Figure optionsDownload full-size imageDownload as PowerPoint slide