无瓣海桑果实提取物对衰老小鼠学习 记忆能力的影响及其机制研究

无瓣海桑果实为真红树无瓣海桑的果实。研究无瓣海桑果实不同提取物对D-半乳糖所致衰老小鼠学习记忆能力影响及其作用机制。采用Morris水迷宫实验测量无瓣海桑果实不同提取物对小鼠的学习记忆能力影响,HE染色观察各组小鼠脑部神经细胞的变化情况,并测定脑组织超氧化物歧化酶(SOD)活力、谷胱甘肽过氧化物酶(GSH-Px)活力、一氧化氮(NO)含量和单胺氧化酶(MAO)活力。结果表明:与模型组相比,无瓣海桑果实不同提取物处理组小鼠在水迷宫实验中逃避潜伏期明显缩短(P0.05),目标象限停留时间明显增加(P0.05)。无瓣海桑果实不同提取物处理组小鼠脑部神经细胞损伤与模型组相比明显减少,小鼠脑部SOD酶活力和GSH-Px酶活力提高(P0.05),NO含量和MAO活力在脑部显著降低(P0.05)。无瓣海桑果实不同提取物对D-半乳糖致衰老小鼠学习记忆能力有改善作用,无瓣海桑果实不同提取物通过提高小鼠脑内源抗氧化酶(SOD、GSH-Px)活力,降低脑部NO含量和MAO活力来提高D-半乳糖致衰老小鼠的学习记忆能力。     

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。     

盐度对无瓣海桑幼苗的生长和某些生理生态特性的影响

本文研究了盐度（０‰～５０‰）对无瓣海桑幼苗生长的影响。盐度对无瓣海桑幼苗长叶数、茎长、植株鲜重、主根长、根系鲜重等方面起抑制作用;随盐度的提高,无瓣海桑幼苗成活率下降;但盐度对无瓣海桑幼苗叶片面积存在一个低盐（０‰～１０‰）促进、高盐（１５‰～４０‰）抑制的过程;盐度对叶绿素含量的影响总趋势是随盐度提高,低盐时叶绿素含量下降,而当盐度超过１０‰时上升。因此认为：１）无瓣海桑幼苗在无盐存在下,也可     

Aerenchyma formation and porosity in root of a mangrove plant,<Emphasis Type="Italic"> Sonneratia alba</Emphasis> (Lythraceae)

Aerenchyma gas spaces are important for plants that grow in flooded and anaerobic sites or habitats, because these gas spaces provide an internal pathway for oxygen transport. The objective of this study is to characterize the development of aerenchyma gas spaces and observe the porosity in roots of Sonneratia alba. Tissue at different developmental stages was collected from four root types, i.e. cable root, pneumatophore, feeding root and anchor root, of S. alba. In S. alba, gas space is schizogenously produced in all root types, and increases in volume from the root meristem to mature root tissues. The aerenchyma formation takes place immediately, or 3–5 mm behind the root apex. At first, cortical cells are relatively round in cross sections (near the root apex); they then become two kinds of cells, rounded and armed, which combine together, forming intercellular spaces behind the root apex. The average dimensions of cortical cells increased more than 1.3 times in the vertical direction and over 3.3 times in the horizontal direction. At maturity, aerenchyma gas spaces are long tuberous structures without diaphragms and with numerous small pores on the lateral walls. Within the aerenchyma, many sclereids grow intrusively. Root porosity in all root types ranged from 0–60%. Pneumatophores and cable roots had the highest aerenchyma area (50–60%).     

国产海桑属植物的两个杂交种

作者通过对红树林海桑属植物进行形态学、花粉学、细胞学以及其它方面的比较研究,证实了拟海桑和海南海桑为两个杂交种,它们的嫌疑亲本分别是杯萼海桑和海桑、杯萼海桑和卵叶海桑·ｓｏｎｎｅｒａｔｉａ×ｈａｉｎａｎｅｎｗｓｉｓｋｏ,ＥＹ．ＣｈｅｎｅｔＷ．Y　Ｃｈｅｎ（ｐｒｏｓｐ）为海南海桑的新名称,而拟海桑S．ｐａｒａｃｓｅｏｌａｒｉｓＫｏ,Ｅ.Ｙ.Ｃｈｅｎ,ｅｔＷ,ＣｈｅｎＹ.Ｃｈｅｎ则被归并入ｓｏｎｎｅｒａｔｉａ×ｇｕｌｎｇａｉＮ.C．Ｄｕｋｅ．     

Genetic variation within the endangered mangrove species Sonneratia paracaseolaris (Sonneratiaceae) in China detected by inter-simple sequence repeats analysis

Sonneratia paracaseolaris, is a critically endangered mangrove species in China. Using inter-simple sequence repeats (ISSR) markers, we compared the genetic variation of introduced populations with that of natural populations to check whether the genetic diversity has been conserved. At the species level, genetic diversity was relatively high (P = 81.37%, He = 0.2241, and SI = 0.3501). Genetic variation in introduced populations (P = 75.78%, He = 0.2291, and SI = 0.3500) was more than that in natural populations (P = 70.81%, He = 0.1903, and SI = 0.2980). Based on Nei's G_ST value, more genetic differentiation among natural populations was detected (G_ST = 0.3591). Our data show that the genetic diversity of S. paracaseolaris was conserved in introduced populations to some extent, however, owing to the small natural populations and the threats they encountered, more plants should be planted to enlarge and restore the populations.     

中国杯萼海桑遗传多样性的ISSR研究

杯萼海桑(Sonneratia alba J.Smith.)是海桑科红树植物,在我国分布于海南岛的东海岸.本文采用简单序列霞复区间扩增(ISSR)分子标记技术对分布于海南岛的杯萼海桑的4个天然居群和东寨港红树林自然保护区引种的一人工居群共100个个体进行了遗传变异分析.11个引物共扩增出133条带,其中103条具多态性,多态位点百分率为77.44%.在居群水平上相对较低,多态位点百分率为51.88%～65.41%,平均为57.74%.期望杂合度、香农信息指数在物种水平上分别为0.227 1和0.348 9;在居群水平上分别为0.1 83 7和0.227 5.依据Gst值,杯萼海桑绝大多数遗传变异发生在居群内的个体间(81.02%),18.98%的遗传变异发生在居群间.AMOVA分析也表明了类似的遗传结构.居群间平均遗传一致度为0.934 2.依据Nei(1972)的遗传距离对不同居群进行UPGMA聚类,将居群分为两组,来自三亚(SY)和陵水(LS)的居群聚为一类;东寨港引种栽培的人工居群(DZ)和琼海(QH)、文昌(WC)的居群聚为另一类.Mantel检验表明,遗传距离与地理距离呈极显著相关.     

Environmental Effects of Canopy Gap Formation in High-Rainfall Mangrove Forests1

This study investigated the importance of gap formation in mangrove swamps on the island of Kosrae, Federated States of Micronesia, in order to understand better both natural processes of forest development and the effects of harvesting trees for firewood in these wetlands. Measurements were concentrated in seven plots located near four rivers: three in fringe zones and four in basin zones. Each plot was a cluster of five points and covered an area of ca 1.3 ha. From every point in each of the seven plots, the nearest canopy gap ≥10 m² was located; 25 of the 35 gaps were formed by harvesting. Porewater salinity was significantly higher under the canopy in fringe mangrove forests than in basin mangrove forests. Although gaps were small (mean gap size = 158 m²; median gap size = 92 m²), soil temperatures were significantly higher in gaps of both zones. Soil redox potential was significantly lower and porewater salinity significantly higher in the gaps than under the canopy in the basin zone only. Higher porewater salinity may be attributed to high evaporation rates from the soil and high transpiration rates from trees surrounding gaps. There were significantly more seedlings in gaps than under the canopy only in the fringe zones. Although gap formation alters the soil environment of Kosraean mangrove swamps, high freshwater input may buffer these effects in basin mangrove swamps by reducing porewater salinity. Current harvesting rates do not appear to be changing canopy species composition, but large gaps, especially in mangrove forests in more arid areas, may lead to major changes.     

A review of mangrove rehabilitation in the Philippines: successes,failures and future prospects

From half a million hectares at the turn of the century, Philippine mangroves have declined to only 120,000 ha while fish/shrimp culture ponds have increased to 232,000 ha. Mangrove replanting programs have thus been popular, from community initiatives (1930s–1950s) to government-sponsored projects (1970s) to large-scale international development assistance programs (1980s to present). Planting costs escalated from less than US$100 to over $500/ha, with half of the latter amount allocated to administration, supervision and project management. Despite heavy funds for massive rehabilitation of mangrove forests over the last two decades, the long-term survival rates of mangroves are generally low at 10–20%. Poor survival can be mainly traced to two factors: inappropriate species and site selection. The favored but unsuitable Rhizophora are planted in sandy substrates of exposed coastlines instead of the natural colonizers Avicennia and Sonneratia. More significantly, planting sites are generally in the lower intertidal to subtidal zones where mangroves do not thrive rather than the optimal middle to upper intertidal levels, for a simple reason. Such ideal sites have long been converted to brackishwater fishponds whereas the former are open access areas with no ownership problems. The issue of pond ownership may be complex and difficult, but such should not outweigh ecological requirements: mangroves should be planted where fishponds are, not on seagrass beds and tidal flats where they never existed. This paper reviews eight mangrove initiatives in the Philippines and evaluates the biophysical and institutional factors behind success or failure. The authors recommend specific protocols (among them pushing for a 4:1 mangrove to pond ratio recommended for a healthy ecosystem) and wider policy directions to make mangrove rehabilitation in the country more effective.