[1] Peking Univ, Coll Life Sci, Beijing 100871, Peoples R China
[2] Peking Univ, Beijing Nucl Magnet Resonance Ctr, Beijing 100871, Peoples R China
[3] Peking Univ, Coll Chem & Mol Engn, Beijing 100871, Peoples R China
[4] Univ Henri Poincare, IFR Genom Ecophysiol & Ecol Fonctionnelles 110, Unite Mixte Rech INRA UHP 1136, F-54506 Vandoeuvre Les Nancy, France