Effects of Seawater Stress on Photosynthetic and Antioxidant Characteristics in Portulaca oleracea Characteristics of Photosynthesis and Chlorophyll Fluorescence in Portulaca oleracea with NaCl Stress Isolation,purification,and structural characterization of polysaccharide POP Ul b from Portulaca oleracea Cyclic dipeptides from Portulaca oleracea Extraction and isolation of polysaccharide from Portulaca oleracea by traditional process combined with membrane separation technology and evaluation of its anti-oxidant activity Preparation of polysaccharides, alkaloids, and polyphenols from fresh Portulaca oleracea and their anti-diabetic effects Isolation and Assaying of polysaccharides in Portulaca oleracea