Determination of chemical species of iodine in some seaweeds .1.

The chemical species of iodine in seven marine algae Codium fragile, Ulva pertusa, Monostroma nitidum, Gracilaria confervoides, Sargassum Kjellmanianum, Dictyopteris divaricata and Laminaria japonica were studied using neutron activation analysis combined with chemical separation. The contents of total iodine, water-soluble iodine, soluble organic iodine, I- and IO3- were determined. The results indicate that the chemical species and contents of iodine in various algae are remarkably different. The highest iodine content of 734 mg/kg (wet basis) was found in Laminaria japonica, with 99.2% of the total iodine being water soluble. The iodine contents of the other six algae are lower and soluble iodine makes up 16-41% of the total. In the aqueous leachate, iodine is mainly I-, which amounts to 61-93% of total water-soluble iodine; the percentages of organic iodine making up 5.5-37.4%, while the contents of IO3- are the lowest, 1.4-4.5%. This result suggests that the mechanism of iodine enrichment is different for various algae and that its bioavailability varies as well. (C) 1997 Elsevier Science B.V.

Extraction of the polysaccharides from five algae and their potential antioxidant activity in vitro

The sulfated polysaccharides extracted from algae possess excellent antioxidant activities. In this study, we prepared five polysaccharides extracted from five algae including one brown alga Laminaria japonica. one red alga Porphyra haitanensis and three green algae Ulva pertusa, Enteromorpha linza and Bryopsis plumose. And then the antioxidant activities of all the samples were investigated including scavenging effects of superoxide and hydroxyl radicals, and reducing power. The chemical analysis and FT-IR spectrum showed these extracts were polysaccharides. And in addition, we found that certain polysaccharide exhibited stronger antioxidant activity in certain antioxidant activity. Factors effecting and attributing to radical scavenging effect need to be further studied. (C) 2010 Elsevier Ltd. All rights reserved.

喀斯特山区先锋植物叶片解剖特征及其生态适应性评价——以贵州花江峡谷区为例

通过研究贵州西南部典型喀斯特植被退化区花江峡谷植被现状，选取具一定经济价值和推广价值的先锋植物，采用生物显微制片技术与数理统计方法相结合，报导了6科10种分属不同生活型的植物叶片的解剖结构特征，并进行了比较和解剖因子分析。结果表明研究区喀斯特先锋植物叶片在不同种类之间具有明显差异，这些差异除受遗传因子控制外，环境因子(主要为光照和水分)也有重要作用；生活型不同对先锋植物叶片特征有一定影响，但未表现出规律性。根据叶片适应特征的差异，10种先锋植物可分为3种类型，即旱生或阳生叶类型的构树(Broussonetia papyrifera)、火棘(pyracantha fortuneana)、刺槐(Robinia pseudoacacia)、白三叶(Trifolium repens)；偏中生叶类型(香椿的Toona sirensis)、顶坛花椒(Zanthaxylum pinum var．dingtanensis)、黔滇木蓝(In-digofera esquirolii)、忍冬(Lomicera japonica)、紫云英(Astragalus sinicus)；偏阴生叶类型的繁缕(Stellaria media)。