Life history of Aulacaspis marina Takagi and Williams(Hom., Coccoidea), a new pest of mangrove plantations in Indonesia, and its damage to mangrove seedlings

Scale insects of a newly described species, Aulacaspis marina Takagi and Williams, have killed a large number of mangrove ( Rhizophora mucronata Lamk.) saplings planted in abandoned shrimp ponds on Bali island, Indonesia. The mean fecundity of A. marina was 141 eggs. The generation time of this species was between 34 and 42 days, based on four generations, suggesting that the species has nine to 10 generations a year on Bali island where the temperatures are seasonally constant. When crawlers of A. marina were transferred to potted seedlings of R. mucronata , they settled on all leaves of the seedlings. Newly expanded leaves were not infested by the first generation crawlers but were attacked by the following generations. The insect attack induced browning of the leaves and finally caused leaf fall; the leaves fell 25–159 days after the crawler transfer. Consequently, the seedlings died on average 128 (range 82–159) days after infestation. This suggests that once a large number of crawlers attack R. mucronata seedlings, A. marina can kill them within several months. When crawlers were transferred to potted seedlings of three mangrove species ( R. mucronata , Rhizophora apiculata Bl. and Bruguiera gymnorrhiza L.), which were the main species planted at the study site, the numbers that developed into adult females did not differ significantly among these species. This suggests that these mangrove species are almost equally susceptible to A. marina.     

海南岛东寨港几种红树植物种间生态位研究

采用3种常见的生态位宽度和生态位重叠计测公式,以外来种无瓣海桑扩散区的秋茄+桐花树群落演替系列作为资源轴,定量计测了几种红树植物的生态位宽度和重叠值.结果表明,各树种生态位宽度值排序为桐花树(3.8357)＞秋茄(3.3421)＞木榄(3.3180)＞白骨壤(3.0975)＞无瓣海桑(2.9137)＞海桑(2.5724)＞角果木(1.8523)＞红海榄(1.6897)＞海莲(1.0000),很好地表征了其生态适应性和分布幅度.各树种重叠值中,以秋茄、桐花树、木榄、白骨壤之间的生态位重叠较大,表明其间存在较强的资源利用性竞争.无瓣海桑生态位宽度处于中等程度,与中低潮滩红树植物海桑、桐花树、秋茄和白骨壤的重叠值相对较高,与红海榄、木榄有中度重叠,与角果木有少量重叠,与海莲完全没有重叠.     

Light-dependent photosynthetic characteristics indicated by chlorophyll fluorescence in five mangrove species native to Pohnpei Island,Micronesia

To investigate the adaptive capacity to strong light among mangrove species, we examined light-dependent properties of photosynthesis in relation to photoinhibition using chlorophyll fluorescence for sun-leaves of five mangrove tree species; Sonneratia alba, Rhizophora stylosa, Rhizophora apiculata, Bruguiera gymnorrhiza and Xylocarpus granatum. These species were classified into three groups; pioneer -S. alba and R. stylosa, intermediate -R. apiculata and B. gymnorrhiza and climax species -X. granatum. A further distinction can be made between the two intermediate species, the less shade-tolerant R. apiculata and the shade-tolerant B. gymnorrhiza. There was a clear association between successional status and light-saturated electron transport rate (ETR) where ETR was higher in S. alba and R. stylosa > R. apiculata and B. gymnorrhiza > X. granatum. Based on its lower initial slope of light-dependent ETR and lower ratio of variable to maximum fluorescence (Fv/Fm) after a dark-adaptation, X. granatum appeared to suffer greater photoinhibition than other species. The response of qP, which represents PSII openness, to incident light indicates a ranking of tolerant capacity to photoinhibition of S. alba and R. stylosa > R. apiculata > B. gymnorrhiza and X. granatum. The difference in qP response between R. apiculata and B. gymnorrhiza might be attributed to the higher leaf absorptance and the lower degree of thermal dissipation indicated by the higher F'v/F'm in B. gymnorrhiza. It appears that the co-ordination of leaf absorptance, thermal dissipation and consumption of absorbed light energy through electron transport is important in the acclimation of mangrove species to exposed habitats.     

中国红树科7种红树植物遗传多样性分析

以红树、红海榄、秋茄、角果木、木榄、海莲、尖瓣海莲等7种红树科植物为材料,采用改进的CTAB法获得了纯度较高、得率高、片段完整的基因组DNA。通过筛选出的15个有效引物进行RAPD分析,探讨了7种树植物间的亲缘关系。15个有效引物共扩增出617条DNA带,其中多态性条带415条,占总扩增条带的67.26%。利用Nei指数法得出7个分类群间的遗传一致度和遗传距离,并运用UPGMA法进行聚类分析。7个分类群分为A、B两个大组,平均遗传距离为0.41。将得出的7个分类群的DNA分子分类系统图,与传统的分类进行比较,发现结果相符。同时获得一个OPG05－900的差异片段可作为区分海莲和尖瓣海莲的分子标记。     

珠海淇澳岛几种红树植物引种的初步研究

将红树植物正红树(Rhizophora apiculata)、海莲(Bruguiera sexangula)和木榄(B.gymnorhiza)从海南岛引种到珠海淇澳-担杆岛省级自然保护区,苗期生长正常。1a生的正红树、海莲和木榄平均苗高分别为45.3cm、28.7cm和56.7cm,平均地径分别为1.34 cm、0.64 cm和1.60 cm,保存率分别为40.9%、59.5%和70.5%。3种红树植物苗期抗寒性大小依次为木榄>海莲>正红树。正红树、海莲和木榄3种红树植物能基本适应引种地的自然条件,对其生长发育特性尚需进行跟踪调查。     

Vivipary in Ophiorrhiza mungos L. – a rare phenomenon in angiosperms

Vivipary, the precocious germination of seeds within the parent plant, is a specialised feature of evolutionary and biological importance that ensures survival of a plant. Reports on vivipary in angiosperms are rare, accounting for <0.1% of flowering plants. Here, we report a remarkable case of occurrence of vivipary in Ophiorrhiza mungos. A study was conducted to collect information on the morphology of the capsules that support vivipary, environmental factors that induce vivipary, survival mode and the survival of viviparous seedlings. The hydroscopic movement of the cup‐shaped capsules of O. mungos was found to help in viviparous germination during the rainy season. Of the total seeds in a capsule, 70% showed viviparous germination. The seedlings remaining inside the capsule attain a height of 0.98 ± 0.4 cm and reach the ground when the capsule falls. On the ground, seedlings obtain easy anchorage to the substratum since they have already germinated. Vivipary appears to be an adaptation of O. mungos to the rainy season for ensuring viable offspring. This suggests that vivipary in this species might be artificially induced by continuous spraying with water to rescue seeds in all seasons for use in large‐scale propagation to meet increasing market demand and conservation of this valuable anticancer medicinal herb.     

Comparative anatomy of intervessel pits in two mangrove species growing along a natural salinity gradient in Gazi bay, Kenya

BACKGROUND AND AIMS: According to the air-seeding hypothesis, embolism vulnerability in xylem elements is linked directly to bordered pit structure and functioning. To elucidate the adaptive potential of intervessel pits towards fluctuating environmental conditions, two mangrove species with a distinct ecological distribution growing along a natural salinity gradient were investigated. METHODS: Scanning and transmission electron microscopic observations were conducted to obtain qualitative and quantitative characteristics of alternate intervessel pits in A. marina and scalariform intervessel pits in Rhizophora mucronata. Wood samples from three to six trees were collected at seven and five sites for A. marina and R. mucronata, respectively, with considerable differences between sites in soil water salinity. KEY RESULTS: Vestured pits without visible pores in the pit membrane were observed in A. marina, the mangrove species with the widest geographical distribution on global as well as local scale. Their thick pit membranes (on average 370 nm) and minute pit apertures may contribute to reduced vulnerability to cavitation of this highly salt-tolerant species. The smaller ecological distribution of R. mucronata was in accordance with wide pit apertures and a slightly higher pitfield fraction (67 % vs. 60 % in A. marina). Nonetheless, its outer pit apertures were observed to be funnel-shaped shielding non-porous pit membranes. No trends in intervessel pit size were observed with increasing soil water salinity of the site. CONCLUSIONS: The contrasting ecological distribution of two mangrove species was reflected in the geometry and pit membrane characteristics of their intervessel pits. Within species, intervessel pit size seemed to be independent of spatial variations in environmental conditions and was only weakly correlated with vessel diameter. Further research on pit formation and function has to clarify the large variations in intervessel pit size within trees and even within single vessels.     

Fungi associated with the aerial parts of Malaysian mangrove plants

The leaf surface fungi associated with nine species of mangrove plants includingAvicennia alba, A. officinalis, Bruguiera parviflora, Ceriops tagal, Rhizophora apiculata, R. mucronata, Sesuvium portulacastrum, Sonneratia alba, andXylocarpus mollucensis were studied using direct observation techniques and leaf washings. Over 40 fungal taxa were isolated from the leaf washings. Of these, species ofAspergillus, Choanephora, Cladosporium, Curvularia, Fusarium, Nigrospora, Penicillium, Pestalotiopsis, Trichoderma, andZygosporium were frequently encountered in the washings of all nine mangrove plants. Fewer species of fungi includingCladosporium oxysporum, Corynespora cassiicola, Fusarium, Penicillium, Pestalotiopsis, andZygosporium were capable of growth on the washed leaves. The major phylloplane fungus on plants with higher leaf tannin content (e.g.B. parviflora, C. tagal, Rhizophora spp., andX. mollucensis) wasPestalotiopsis. Leaves with relatively lower amounts of tannin supported the proliferation ofFusarium as the major fungus. Fungi were present on the plumule and cotyledonous sheath even before the leaves opened.Pestalotiopsis persisted throughout the development and growth of the leaves. Many of the fungi encountered on senescent leaves have been reported in earlier studies to be the primary colonisers of submerged decaying leaves.     

Vivipary in coastal cacti: a potential reproductive strategy in halophytic environments

Vivipary, the germination of seeds within the fruit prior to abscission from the maternal plant, is an important event in plants. Two main types of vivipary are known in vascular plants: true vivipary and pseudovivipary. In crop grasses, pseudovivipary is an undesirable character as it results in lower yields. To date, vivipary in the Cactaceae has been reported for less than 20 species, most of which are cultivated. Here, we report viviparous (cryptoviviparous-a subcategory of true vivipary) cacti in nature in members of the tribes Cacteae and Pachycereeae (subfamily Cactoideae). We present four species inhabiting coastal plains in areas subject to periodic flooding, namely, Ferocactus herrerae, Stenocereus alamosensis, S. thurberi, and Pachycereus schottii. These species from localities in northwestern Mexico had viviparous fruits and offspring in different stages of development. A potential trend in the data indicates that the overall proportion of viviparous plants is higher in coastal flooding areas relative to halophytic, nonflooding areas. In our view, vivipary is a reproductive strategy that has evolved to provide a more efficient mechanism favoring germination and new avenues for survival by contributing to population maintenance and short-distance dispersal on halophytic substrates.     

Stable soil pH of thai mangroves in dry and rainy seasons and its relation to zonal distribution of mangroves

Soil characteristics of mangrove forests at Amphur Laemngob, Trat Province, east Thailand were investigated in both dry andrainy seasons. Sonneratia alba, Avicennia alba andRhizophora mucronata mainly grew as seaward mangroves.Rhizophora apiculata, Ceriops tagal, Excoecaria agallocha andBruguiera gymnorrhiza grew as meso mangroves in most cases.Lumnitzera racemosa was found as a landward mangrove. The salinity of the soil in which these 8 species grew was significantly higher in the dry season than in the rainy season. Soil pH did not change irrespective of the season. Each species seemed to grow at inherent soil pH. Bruguiera gymnorrhiza, Sonneratia alba andAvicennia marina were found both in Japan and Thailand. The soil pH of each mangrove species was similar in Japan and Thailand. The soil salinity of each mangrove species in Japan was similar to that in Thailand in the dry season. It was suggested that soil pH and salinity in the dry season are the important factors governing the zonal distribution of mangroves.     

The current status of mangroves along the Kenyan coast: a case study of Mida Creek mangroves based on remote sensing

Mangroves form a unique ecosystem of limited extent covering an area of about 53 000 ha along the Kenyan coast which need protection from overexploitation. Background information on the areal extent and status of these mangroves is limited and makes their protection and management difficult.A model study has been carried out on the Mida Creek mangroves based on a double sampling approach starting with SPOT multispectral satellite imagery followed by ground checks to provide information on species composition, density and distribution of mangroves. The utilization of mangroves and uses around and within the mangroves were determined.During this study, seven mangrove species were identified in Mida Creek, namely:Avicennia marina, Bruguiera gymnorrhiza, Ceriops tagal, Rhizophora mucronata, Sonneratia alba, Xylocarpus granatum andLumnitzera racemosa. This report briefly outlines the present utilisation of mangrove species. It is recommended that a multidisciplinary management plan be developed in order to conserve and manage the mangroves of Kenya on a sustainable yield basis.     

2008年南方低温对我国红树植物的破坏作用

2008年初, 我国南方19个省经历了50年一遇的持续低温雨雪冰冻天气。极端气候对华南沿海各省的红树林区造成不同程度的危害。2008年3月, 在我国南方各省红树林区的10个代表性地点, 对这次寒害造成的红树植物伤害程度进行了系统的调查。结果表明: 冬季低温对红树林的影响极为显著, 特别是在低纬度的海南、广西和广东湛江, 由于极端低温正值夜间退潮, 对红树林的影响更为显著; 在纬度较高的福建, 本地红树种类秋茄(Kandelia obovata)、桐花树(Aegiceras corniculatum)和白骨壤(Avicennia marina)及引种的木榄(Bruguiera gymnorrhiza)等, 由于长期适应于冬季较低的气温或在种植前经过抗寒锻炼, 具有较强的抗寒能力。各地主要红树植物中, 广布种秋茄、桐花树和白骨壤最为耐寒, 其耐寒性均大于红树科的木榄、海莲(Bruguiera sexangula)和红海榄(Rhizophora stylosa)。海桑(Sonneratia caseolaris)对温度的敏感性最强, 抗寒能力最低, 因此, 即使在其原产地海南也受到较为严重的寒害, 在纬度更高的引种地出现大面积受害甚至全部死亡, 而从孟加拉国引种的无瓣海桑(Sonneratia apetala)却显示出一定的抗寒能力。同一地点的红树植物幼苗的抗寒能力低于大树。此次寒害也造成了苗圃场的种苗大量死亡, 成熟的植株提前落花落果, 这势必会影响后继一两年内红树林的自然更新和人工造林。因此, 在未来红树林造林或人工引种中, 一定要考虑到红树植物的抗寒能力。     

Fungi associated with the aerial parts of Malaysian mangrove plants

The leaf surface fungi associated with nine species of mangrove plants includingAvicennia alba, A. officinalis, Bruguiera parviflora, Ceriops tagal, Rhizophora apiculata, R. mucronata, Sesuvium portulacastrum, Sonneratia alba, andXylocarpus mollucensis were studied using direct observation techniques and leaf washings. Over 40 fungal taxa were isolated from the leaf washings. Of these, species ofAspergillus, Choanephora, Cladosporium, Curvularia, Fusarium, Nigrospora, Penicillium, Pestalotiopsis, Trichoderma, andZygosporium were frequently encountered in the washings of all nine mangrove plants. Fewer species of fungi includingCladosporium oxysporum, Corynespora cassiicola, Fusarium, Penicillium, Pestalotiopsis, andZygosporium were capable of growth on the washed leaves. The major phylloplane fungus on plants with higher leaf tannin content (e.g.B. parviflora, C. tagal, Rhizophora spp., andX. mollucensis) wasPestalotiopsis. Leaves with relatively lower amounts of tannin supported the proliferation ofFusarium as the major fungus. Fungi were present on the plumule and cotyledonous sheath even before the leaves opened.Pestalotiopsis persisted throughout the development and growth of the leaves. Many of the fungi encountered on senescent leaves have been reported in earlier studies to be the primary colonisers of submerged decaying leaves.     

中国东南部海岸红树林的类群及其分布

一、前言 红树林是泛热带的海岸植物群落,我国东南沿海的广东、广西、台湾、福建四省(区)有自然分布。1958年后浙江省也引种成功一种(江惟礼等,1959)。由于红树植物富含丹宁,可供提取鞣素作制革、染渔具渔服,并且木材坚硬,可作建筑材、家具等用途,林下生境是经济鱼虾的滋生场所,还可促淤沉积,扩大海滩以及护堤防风、保护农田和村庄等效益。在理论上,红树林还是河口生态系统的重要的第一生产者之一,是调节海湾河口生态平衡的重要因素。为了保护和发展我国的红树林,因而有必要探讨我国红树林的生态学特征和生物资源及其经营管理。     

大亚湾红树林研究Ⅱ,澳头港部分红树植物的生态生理

对大亚湾澳头港的３种红树植物的光合速率、呼吸速率和蒸腾速率进行测定,结果表明：桐花树、白骨壤和木榄的光合速率日进程呈双峰曲线,日平均光合速率的大小为桐花树＞木榄＞白骨壤,而日均呼吸速率的大小为桐花树＞白骨壤＞木榄,呼吸速率的变化幅度小于光合速率,提示白骨壤的生产力最低,可能与其所处的生境含盐量更高有关。蒸腾速率日进程呈单峰曲线,且泌盐植物桐花树和白骨壤的日均值很接近,都高于拒盐种木榄,表明蒸腾速率与它们的泌盐或拒盐生理特性密切相关。总体上,这些红树植物具有较高的光合速率、较低的呼吸速率和蒸腾速率,有利于生长在盐渍淹水的特殊海滩环境。     

Population dynamics of a Sonneratia caseolaris stand in the Lam River estuary of Vietnam: a restoration perspective

Species composition, age distribution, and their relationship with land height from the datum line (LH) of the Sonneratia caseolaris stand, which grows in the Lam River estuary in Vietnam, were surveyed to obtain fundamental knowledge that aimed at contributing to mangrove restoration. The data gathered on the sandbar consists of three mangrove species and one mangrove associate species, with one non-mangrove species, and were divided into three communities. In terms of the age distribution of the S. caseolaris–Aegiceras corniculatum community, the tree-phase densities for both species are lower than those exhibited by younger phases. In its succession, the seedlings of S. caseolaris and A. corniculatum are primarily recruited at the mean tide level (MWL) in the early stages. Then, A. corniculatum expands to the lower tide zone primarily on mud flat bare land. For both species, full irradiance on the bare land in the low tide zone below MWL is crucial for growth, but S. caseolaris, which propagates by releasing small seeds, can barely survive in the low tide zone because its seeds are easily flushed away. In contrast, A. corniculatum, which propagates using crypto-viviparous seedlings, has a higher survival rate in the low tide zone. As a result, the LH of seedlings of A. corniculatum distribution is significantly lower than that of the distribution of S. caseolaris trees (p?<?0.05). It is important to provide appropriate environmental conditions for forest restoration in order to promote succession. The findings from the current study on population dynamics related to LH and tidal conditions are expected to be applied to platforms for S. caseolaris stands and mangrove restoration.

     

Lipid composition of mangrove and its relevance to salt tolerance

Lipid compositions of mangrove trees were studied in relation to the salt-tolerance mechanism. Leaves and roots were obtained from seven mature mangrove trees on Iriomote Island, Okinawa: Bruguiera gymnorrhiza, Rhizophora stylosa, Kandelia candel, Lumnitzera racemosa, Avicennia marina, Pemphis acidula and Sonneratia alba. Lipids of mangrove leaves mainly consisted of 11 lipid classes: polar lipids, unknown (UK) 1–6, sterols, triacyl glycerols, wax ester and sterol ester (UK 3 and 4 were found to be tri-terpenoid alcohol in this study). Of these lipid classes, sterol ester was the main lipid in all species comprising 17.6–33.7% of total lipids. Analysis of the chemical structure found that the sterol esters mainly consisted of fatty acid esters of tri-terpenoid alcohols. One major tri-terpenoid alcohol was identified to be lupeol by interpretation of infrared resonance, nuclear magnetic resonance and mass spectrometry. Because of the unique anatomy of the mangrove root, lipid analyses were made separately for epidermis, cortex and innermost stele, respectively. The concentration of free tri-terpenoid alcohols showed a higher tendency in the outside part than in the inside portion of the roots, suggesting their protective roles. Relevance of lipid composition to salt tolerance was studied with propagules of K. candel and B. gymnorrhiza planted with varied salt concentrations. The proportions of free tri-terpenoids increased with salinity in both leaves and roots of K. candel, and only in roots of B. gymnorrhiza. No salt-dependent changes were noted in the phospholipid and fatty acid compositions in both species. These findings suggested that salt stress specifically modulated the terpenoid concentrations in mangroves. Electronic Publication     

Effects of salinity on photosynthesis,leaf anatomy,ion accumulation and photosynthetic nitrogen use efficiency in five Indian mangroves

Five species of mangroves (Bruguiera gymnorrhiza, Excoecaria agallocha, Heritiera fomes, Phoenix paludosa and Xylocarpus granatum) were investigated with respect to their photosynthesis rate, chlorophyll content, mesophyll conductance, specific leaf area, stomatal conductance and photosynthetic nitrogen use efficiency under saline (15–27 PPT) and non-saline (1.8–2 PPT) conditions. Some inorganic elements were estimated from the leaf samples to compare the concentrations with change in salinity. Elevated assimilation rate coupled with increased chlorophyll content, more mesophyll and stomatal conductance and higher specific leaf area in non-saline condition indicates that these mangroves can grow well even with minimal salinity in soil. In B. gymnorrhiza, E. agallocha and P. paludosa the optimum PAR acquisition for photosynthesis was higher under salt stress, while the maximal rate of assimilation was lower even with minimal salinity. H. fomes and X. granatum followed the opposite trend, where the peak photosynthesis rate was lower under non-saline conditions even at a higher irradiance than in the saline forest. This indicates less affinity of H. fomes and X. granatum to high substrate salinity. Accumulation of Na⁺ increased in plants in saline substrate, while in most of the species, salinity imposed reduction in Ca⁺ and Mg⁺ uptake. Increased K⁺ content can be attributed to high substrate level K⁺ in non-saline soil. Trace amount of salinity induced Cu⁺⁺ detected in leaves of H. fomes may impart some toxic effects. Photosynthetic nitrogen use efficiency increased in non-saline soil that can be attributed to higher photosynthetic peak in most of the species and/or lower nitrogen accumulation in plant samples.     

Growth and water use of the mangroves Rhizophora apiculata and R. stylosa in response to salinity and humidity under ambient and elevated concentrations of atmospheric CO2

Two mangrove species, Rhizophora apiculata and R. stylosa, were grown for 14 weeks in a multifactorial combination of salinity (125 and 350 mol m^?3 NaCl), humidity (43 and 86% relative humidity at 30°C) and atmospheric CO₂ concentration (340 and 700 cm³ m^?3). Under ambient [CO₂], growth responses to different combinations of salinity and humidity were consistent with interspecific differences in distribution along natural gradients of salinity and aridity in northern Australia. Elevated [CO₂] had little effect on relative growth rate when it was limited by salinity but stimulated growth when limited by humidity. Both species benefited most from elevated [CO₂] under relatively low salinity conditions in which growth was vigorous, but relative growth rate was enhanced more in the less salt-tolerant and more rapidly growing species, R. apiculata. Changes in both net assimilation rate and leaf area ratio contributed to changes in relative growth rates under elevated [CO₂], with leaf area ratio increasing with decrease in humidity. Increase in water use efficiency under elevated [CO₂] occurred with increase, decrease or no change in evaporation rates; water use characteristics which depended on both the species and the growth conditions. In summary, elevated [CO₂] is unlikely to increase salt tolerance, but could alter competitive rankings of species along salinity × aridity gradients.