红树植物人工湿地对生活污水的净化效果

研究了潜流型海桑（Sonneratia caseolaris）人工湿地、桐花树（Aegiceras corniculatum）人工湿地和木榄（Bruguiera gymnorrhiza）人工湿地对生活污水的净化效果。一年来,3种红树植物人工湿地对BOD5、CODCr、TP、TN、NH4^＋-N和NO2^--N的平均去除率分别达到83%、71%、41%、55%、50%和84%以上。人工湿地各处理周期之间,BOD5和CODCr去除率波动较小,而TP、TN、NH4^＋-N和NO2^--N去除率波动较大。3种红树植物人工湿地对各种污染物的净化效果存在一定的差异。海桑人工湿地和桐花树人工湿地对BOD5、CODCr、TP、TN和NH4^＋-N去除率明显高于木榄人工湿地,而海桑人工湿地和桐花树人工湿地相比较,除TP外,BOD5、CODCr、TN和NH4^＋-N去除率没有显著差异。人工湿地单一处理周期内,去除率随水力停留时间（HRT）的延长而增加。BOD5、CODCr、TN和NH4^＋-N在HRT为1d和2d的去除率分别为HRT为3d去除率的54%-65%和73%-84%,NO2^--N在HRT为1d和2d的去除率分别达到了HRT为3d的70%-81%和85%-94%,而TP在HRT为1d和2d的去除率分别只有HRT为3d的39%-50%和65%-74%。另外,红树植物人工湿地与风车草（Cyperus alternifoliu）人工湿地相比,前者的BOD5、CODCr、TP、TN和NH4^＋-N去除率明显小于后者（P〈0.05）。总体上看,3种红树植物人工湿地对生活污水的净化效果呈现海桑人工湿地≈桐花树人工湿地〉木榄人工湿地。     

药用红树木榄胚轴抗HBV化学成分的研究

红树木榄(Bruguiera gymnorhiza)胚轴为京族常用治疗乙肝中草药。为研究木榄胚轴中化学成分及其抗乙型肝炎病毒(hepatitis B virus,HBV)活性,该文采用MTT法和实时荧光定量PCR方法测定木榄胚轴不同萃取部位抗HBV活性,使用现代色谱和波谱方法对活性萃取部位的化学成分进行分离鉴定,并测试获得的化学成分抗HBV活性。结果表明:(1)红树木榄胚轴的正丁醇萃取部位具有抗HBV活性;(2)从中分离了11个化合物,分别鉴定为尿嘧啶(1)、胸腺嘧啶(2)、腺嘌呤核苷(3)、oryzalactam(4)、正丁基-O-D-吡喃果糖苷(5)、nortetillapyrone(6)、(4R,6S)-4-methoxyl-2,3-dihydroaquilegiolide(7)、(4R,6S)-2-dihydromenisdaurilide(8)、没食子儿茶素(9)、1-(4-hydroxy-3-methoxy)-phenyl-2-[4-(1,2,3-trihydroxypropyl)-2-methoxy]-phenoxy-1,3-propandiol(10)和(-)-南烛木树脂酚-9-O-β-D-木吡喃糖苷(11),其中化合物4、5、7和8为首次从药用红树木榄中获得,化合物4具有抗HBV 活性,其抑制率为23.59%。该研究丰富了木榄胚轴抗HBV化学成分。     

盐度对红树植物海莲幼苗的生长和某些生理生态特性的影响

本文主要探讨了不同盐度海水砂培的海莲幼苗生长量和某些生理生态特性与盐度的相关效应。结果表明,生长基盐度20‰以上,海莲繁殖体的萌苗时间推迟,成活率降低;随着盐度的提高,幼苗高生长量降低,叶片变小;叶片叶绿素含量随盐度提高而提高,相反的叶片可溶性糖含量则降低,而叶片可溶性蛋白质含量变化不明显;叶片组织内氯含量随盐度提高而提高;随着盐度的提高,叶片蒸腾作用减弱,气孔导度降低。由此表明,海莲幼苗适宜生长的盐度范围在15‰以下,更高的盐度表现为生态抗盐适应性生长。     

Investigations on the antioxidative defence responses to NaCl stress in a mangrove, Bruguiera parviflora: Differential regulations of isoforms of some antioxidative enzymes

Two-month-old healthy seedlings of a true mangrove, Bruguiera parviflora, raised from propagules in normal nursery conditions were subjected to varying concentrations of NaCl for 45 d under hydroponic culture conditions to investigate the defence potentials of antioxidative enzymes against NaCl stress imposed oxidative stress. Changes in the activities of the antioxidative enzymes catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (POX), glutathione reductase (GR) and superoxide dismutase (SOD) were assayed in leaves to monitor the temporal regulation. Among the oxidative stress triggered chemicals, the level of H₂O₂ was significantly increased while total ascorbate and total glutathione content decreased. The ratio of reduced to oxidized glutathiones, however, increased due to decreased levels of oxidized glutathione in the leaf tissue. Among the five antioxidative enzymes monitored, the APX, POX, GR and SOD specific activities were significantly enhanced at high concentration (400 mM NaCl), while the catalase activities declined, suggesting both up and downregulations of antioxidative enzymes occurred due to NaCl imposed osmotic and ionic stress. Analysis of the stress induced alterations in the isoforms of CAT, APX, POX, GR and SOD revealed differential regulations of the isoforms of these enzymes. In B. parviflora one isoform of each of Mn-SOD and Cu/Zn-SOD while three isoforms of Fe-SOD were observed by activity staining gel. Of these, only Mn-SOD and Fe-SOD2 content was preferentially elevated by NaCl treatment, whereas isoforms of Cu/Zn-SOD, Fe-SOD1 and Fe-SOD3 remained unchanged. Similarly, out of the six isoforms of POX, the POX-1,-2,-3 and -6 were enhanced due to salt stress but the levels of POX-4 and -5 remained same as in control plants suggesting preferential upregulation of selective POX isoforms. Activity staining gel revealed only one prominent band of APX and this band increased with increased salt concentration. Similarly, two isoforms of GR (GR1 and GR2) were visualized on activity staining gel and both these isoforms increased upon salt stress. In this mangrove four CAT-isoforms were identified, among which the prominent CAT-2 isoform level was maximally reduced again suggesting differential downregulation of CAT isoforms by NaCl stress. The results presented in this communication are the first report on the resolutions of isoforms APX, POX and GR out of five antioxidative enzymes studied in the leaf tissue of a true mangrove. The differential changes in the levels of the isoforms due to NaCl stress may be useful as markers for recognizing salt tolerance in mangroves. Further, detailed analysis of the isoforms of these antioxidative enzymes is required for using the various isoforms as salt stress markers. Our results indicate that the overproduction of H₂O₂ by NaCl treatment functions as a signal of salt stress and causes upregulation of APX, POX, GR and deactivations of CAT in B. parviflora. The concentrations of malondialdehyde, a product of lipid peroxidation and lipoxygenase activity remained unchanged in leaves treated with different concentrations of NaCl, which again suggests that the elevated levels of the antioxidant enzymes protect the plants against the activated oxygen species thus avoiding lipid peroxidation during salt stress.     

Tracking Human Disturbance in Mangroves: Estimating Harvest Rates on a Micronesian Island

Disturbance is an integral component in mangrove forest dynamics, influencing forest structure, composition, and function. The impacts of human disturbance, however, threaten mangrove forests throughout the world. Small-scale wood harvesting on the small Pacific island of Kosrae, Federated States of Micronesia, provided an instructive scenario for exploring the dynamics of human disturbance. Natural disturbances on the island are rare, but the growing island population harvests mangrove trees for firewood and construction materials, placing pressure on the forest. In order to determine recent harvest rates, we estimated gap ages by developing a time scale for mangrove wood decomposition and by quantifying growth rates for Rhizophora apiculata and Bruguiera gymnorhiza seedlings. Stump and log decomposition patterns were useful in aging gaps, although some patterns were more reliable than others. Seedlings of both species added approximately 5 nodes/year depending on light conditions. The island-wide harvest rate was 10% over the last 10 years, but the rates varied widely among different parts of the island. Rhizophora apiculata has been harvested preferentially, and a dearth of young trees where harvesting has been heaviest portends a decline of this highly desired species in the forest. Socio-economic data substantiated some but not all of the trends we observed. Even on a small island, local differences in both natural and anthropogenic factors are important to understanding forest dynamics.     

盐胁迫下木榄幼苗叶片的解剖学变化

对梯度盐度下木榄(Bruguiera gymnorrhiza)幼苗叶解剖特征进行观察,并分析木榄适应盐胁迫的形态学变化特点以及盐胁迫对植物生长的影响.在0‰～50‰盐度范围内,木榄胚轴均能正常萌发,但幼苗高度、鲜重以及叶面积与培养盐度之间存在着明显的负相关.随着盐度的增加,木榄叶的上(下)角质层和上(下)表皮层增厚,单宁细胞密度增大,上(下)内皮层变薄,叶肉细胞的胞间隙缩小;栅栏组织厚度因细胞的长度和宽度减小而变薄,而海绵组织厚度与培养盐度之问无明显的相关性,栅栏组织/海绵组织的比率下降.扫描电镜下栅栏组织细胞中的叶绿体数量和形态未见明显的变化,但叶绿体在细胞中的位置发生了改变.因此,盐胁迫下叶片栅栏组织厚度的下降、海绵组织中胞间隙的减少以及叶肉细胞中叶绿体的分布变化可能是导致植株光合效率下降和幼苗生长受阻的重要原因.     

红树植物木榄种群高度结构的分形特征

 采用计测等值线分形维数的方法,探讨山口国家级红树林自然保护区内的木榄(Bruguiera gymnorrhiza)种群高度结构的特征。结果表明,木榄种群的高度结构具有分形的特征,其计盒维数介于1.61～1.90之间,信息维数介于1.63～1.84之间,分形维数的高低主要与幼树个体的数量、个体的集聚程度和高度层次结构的复杂程度等密切相关。计盒维数定量描述种群占据垂直空间的能力和程度,而信息维数揭示种群高度层次细节的尺度变化强度和个体高度分布的非均匀性程度。分析表明,等值线法能够有效地表征木榄种群高度结构的分     

人工湿地污水处理系统3种红树植物生理生态特性

研究了淡水条件下潜流型人工湿地污水处理系统中红树植物海桑、桐花树和木榄的生理生态特性。一年后,海桑、桐花树和木榄株高增长量分别为134、32cm和21cm,基径增长量分别为18.2、14.3mm和12.9mm,生物量增长量分别为747、113g/株和55g/株,表明海桑生长最快,桐花树次之,木榄最慢。从2004年1月至12月,海桑、桐花树和木榄各项生理指标的平均值分别为:叶片总叶绿素含量1.91、1.26、0.91mg/gFW,叶绿素a含量1.44、0.93、0.64mg/gFW,叶绿素b含量0.5、0.34、0.17mg/gFW,净光合速率9.67、6.39、3.57μmolCO2/(m2·s),蒸腾速率54、38、24mmolH2O/(m2·s),气孔导度285、222、110mmolH2O/(m2·s),电解质渗出率10.2、12.9、13.5%和SOD活性447、396、386U/gFW。结果表明光合作用和水分代谢海桑>桐花树>木榄,植物受伤害程度海桑<桐花树≈木榄。另外,3种红树植物全年的生理生态特征的变化规律基本相似,4～10月份生长较快,大部分生理指标维持高水平,1～3月份和11～12月份由于温度较低,生长比较慢,大部分生理指标处于较低水平。综合比较一年来人工湿地中3种红树植物的各项生理生态特征,结果显示海桑好于桐花树,桐花树好于木榄。     

红树植物木榄胚轴中苯丙素类化学成分研究

从木榄胚轴中分离出7个苯丙素类化合物,运用波谱学确定了化合物结构,分别鉴定为莨菪亭(1)、Balanophonin(2)、开环异落叶松脂素(3)、臭失菜素A(4)、松脂素(5)、5'-甲氧基-(-)-松脂素(6)、Lyoniresinol-3α-O-β-D-glucopyranosides(7)。化合物1,3,7对肿瘤细胞株A549显示出弱抑制活性,IC50值分别为290.2、323.0、209.3μg/mL。除化合物3和5以外,其他化合物均首次从该植物中分离得到。     

红树植物木榄有机溶剂提取物对球形棕囊藻的抑制效应

基于化感作用原理,利用有机溶剂对红树植物木榄(Bruguiera gymnorrhiza)叶片中的活性物质进行连续提取分离,分别得到正己烷相、乙酸乙酯相、正丁醇相和水相提取物。利用这些提取物进行抑藻实验,通过测定球形棕囊藻(Phaeocystis globosa)的细胞密度发现:四种组分提取物对球形棕囊藻均具有显著的化感抑制作用;正己烷相和乙酸乙酯相提取物对球形棕囊藻的抑制效果明显优于正丁醇相和水相提取物的抑制效果。正己烷相提取物和乙酸乙酯相提取物对球形棕囊藻的48hEC₅₀分别为14.90mg/L和12.18mg/L。研究表明,藻细胞初始接种密度影响提取物的抑藻效应,低接种密度时抑制率极高,而随着接种密度的升高抑制率下降;接种密度极高时,提取物不但不会抑制甚至还会促进藻细胞的生长。