角果木的育苗与造林技术

角果木是红树林的主要组成树种之一。文章介绍了角果木的生物学特性,并总结了角果木营养袋育苗技术、幼苗造林与管护措施,为红树林苗木生产和生态恢复提供技术指导,对提高广东省红树林生物多样性具有重要意义。     

角果木内生真菌Cladosporium cladosporioides JG-12次生代谢产物及其生物活性

采用多种柱色谱技术对角果木内生真菌Cladosporium cladosporioides JG-12的次生代谢产物进行分离纯化,通过波谱数据分析,结合理化常数对化合物的结构进行鉴定,同时,对化合物的抗菌活性、乙酰胆碱酯酶抑制活性以及全齿复活线虫(Panagrellus redivivus)抑制活性进行测试。结果表明,从角果木内生真菌Cladosporium cladosporioides JG-12的次生代谢产物中分离鉴定了6个化合物,分别为:(5S)-5-hydroxy-7-(4"-hydroxy-3"-methoxy-phenyl)-1-phenyl-3-heptanone(1),ilicicolin H(2),2-chloro-3,5-dimethoxybenzyl alcohol(3),(7R)-methoxypurpuride(4),(5a S,9S,9a S)-1,3,4,5,5a,6,7,8,9,9a-decahydro-6,6,9a-trimethyl-3-oxonaphtho[1,2-c]furan-9-yl N-acetyl-L-valinate(5),ergosterolperoxide(3β-hydroxy-5,8-epidioxy-ergosta-6,22-diene)(6)。其中,化合物1具有抗青枯雷尔氏菌(Ralstonia solanacearum)和金黄色葡萄球菌(Staphylococcus aureus)的活性,化合物3具有抗白色念珠菌(Candida albicans)的活性;化合物1和3~5具有全齿复活线虫抑制活性;化合物1~5具有乙酰胆碱酯酶抑制活性。     

Mangrove species zonation and soil redox state,sulphide concentration and salinity in Gazi Bay (Kenya), a preliminary study

The relationship between soil redox state, sulphide concentration, salinity and spatial patterns of mangrove species distribution was investigated in the mangrove forest of Gazi Bay (Kenya). Field measurements were conducted to examine the relationship between species distribution along a band transect of 280m and soil redox potential (Eh) and sulphide patterns, as well as the indirectly related (through flooding regimes) soil salinity. Of the three major species Avicenniamarina, Ceriops tagal and Rhizophoramucronata present along the transect, only the distribution of the latter correlated with the measured soil variables, R. mucronata being absent from the lessreduced zone with high salinity. Bruguieragymnorhiza and Heritieralittoralis occur in minor populations, they are restricted to the saline, sulphidepoor and lessreduced substrates. From the results it is concluded that soil redox potential (Eh), sulphide concentration and salinity may contribute to structure mangroves through the distribution of dominant species, however in combination with other environmental conditions and processes of vegetation dynamics.     

角果木Mn-SOD基因分离及其在酵母中的功能鉴定

为明确抗氧化系统在植物抵御盐胁迫中的作用,采用RT-PCR的方法分离角果木抗氧化酶相关基因Mn-SOD,采用酶切连接法构建酵母表达载体p YES2/Mn SOD,获得含有重组质粒的酵母菌INVScⅠ(p YES2/Mn SOD)能有效表达Mn SOD特异蛋白带。高浓度盐胁迫筛选结果表明,Mn-SOD基因在酵母中的表达能明显提高酵母菌INVSCⅠ的耐盐性。     

角果木根系盐胁迫的防御机理

以强耐盐性红树植物角果木为研究对象,采用不同浓度的NaCl溶液(0,150,300,450mmol·L-1)对角果木幼苗进行盐胁迫处理,测定角果木根部的SOD,POD,ASA,MDA等生理指标。结果表明:角果木在适应盐环境的过程中有新的蛋白产生,在盐胁迫早期(≤9h)MDA含量急剧上升,这种信号诱导了抗氧化防御系统的启动,使角果木根部抗氧化酶类及抗氧化物质均有所增加,说明角果木盐胁迫下通过启动抗氧化酶类、抗氧化物质以清除活性氧对根部的损伤,而后开始适应外界盐环境。     

不同生境下角果木木材结构变化的适应意义

研究了中、高潮位生境角果木的木材结构特征。与高潮位生境生长的角果木木材结构特征相比,中潮位生境生长的角果木木材结构特征有利于提高水分输导的安全性和增强抗风浪冲击的能力。     

Enhancement of growth in mangrove plant (Ceriops tagal) by Rhizophagus clarus

The present study was conducted to investigate the growth response of Ceriops tagal Perr.) C.B. Robinson a mangrove species belonging to the family Rhizophoraceae. Three dominant native arbuscular mycorrhizal (AM) fungal species viz., Rhizophagus clarus, R. intraradices, and Acaulospora laevis were selected. The results revealed that the Mycorrhizal Plant Responsiveness (MGR) was greater in AM inoculated plants compared to control plants. Among AM fungal treatments, plants inoculated with R. clarus recorded significant increase in growth responses compared to remaining AM treatments. The study suggests that R. clarus was the most efficient AM species exhibiting greater influence on growth and biomass. Differences in growth parameters between AM inoculated treatments and control are reasonably linked to colonization levels. The result of the present study indicates that potential native AM fungal species can be use in mangrove reforestation programs as bio-inoculum.