Macroalgal meadow habitats support fish and fisheries in diverse tropical seascapes

Canopy‐forming macroalgae can construct extensive meadow habitats in tropical seascapes occupied by fishes that span a diversity of taxa, life‐history stages and ecological roles. Our synthesis assessed whether these tropical macroalgal habitats have unique fish assemblages, provide fish nurseries and support local fisheries. We also applied a meta‐analysis of independent surveys across 23 tropical reef locations in 11 countries to examine how macroalgal canopy condition is related to the abundance of macroalgal‐associated fishes. Over 627 fish species were documented in tropical macroalgal meadows, with 218 of these taxa exhibiting higher local abundance within this habitat (cf. nearby coral reef) during at least one life‐history stage. Major overlap (40%–43%) in local fish species richness among macroalgal and seagrass or coral reef habitats suggest macroalgal meadows may provide an important habitat refuge. Moreover, the prominence of juvenile fishes suggests macroalgal meadows facilitate the triphasic life cycle of many fishes occupying diverse tropical seascapes. Correlations between macroalgal canopy structure and juvenile abundance suggests macroalgal habitat condition can influence levels of replenishment in tropical fish populations, including the majority of macroalgal‐associated fishes that are targeted by commercial, subsistence or recreational fisheries. While many macroalgal‐associated fishery species are of minor commercial value, their local importance for food and livelihood security can be substantial (e.g. up to 60% of landings in Kenyan reef fisheries). Given that macroalgal canopy condition can vary substantially with sea temperature, there is a high likelihood that climate change will impact macroalgal‐associated fish and fisheries.     

不同基质处理对淡水浇灌桐花树成苗率及幼苗生长的影响

为探索桐花树的淡水化人工培育技术以及筛选适宜的基质,以塘泥、黄心土、河沙和椰糠为试验材料,通过不同的配比组合成10种混配基质,并进行育苗试验,对桐花树的成苗率以及生长情况进行研究。结果发现,不同的混配基质对桐花树的成苗率、苗高、地径、根系生长、鲜重和干重等指标有明显的影响,其中以基质F（30%塘泥+50%黄心土+10%河沙+10%椰糠）综合得分最高,其平均苗高、地径、主根长、一级侧根数、全株生物量、成苗率分别比综合得分最低的基质高24.3%、11.1%、6.3%、6.5%、37.5%、2.0%。     

欧美国家针叶树容器苗生产与启示

针叶树是芬兰、瑞典、挪威、美国、加拿大等欧美国家主要的商品林树种。容器苗是针叶树重要的育苗类型。与裸根苗比较，容器苗具有育苗周期更短、造林季节可延长、苗木适应性更广、苗木质量更一致的优点。因此，容器育苗成为精准林业发展的必然趋势。为了借鉴欧美容器育苗的技术方法，提高我国容器苗的质量，为我国针叶树容器苗发展提供参考，文中主要从4个方面综述了欧美国家检测与提高苗木质量的方法，即列举了针叶树常用的苗木质量检测指标，总结了育苗容器与育苗基质的改良进展，介绍了养分、水分、光照与温度等培养条件的优化手段，简要概述了容器苗病虫害防控的进展，提出了我国相关树种容器苗生产的启示与借鉴。     

Use of short-day treatment in the production of Norway spruce mini-plug seedlings under plant factory conditions

Mini-plug transplant seedlings of Norway spruce have been cultivated in closed growth systems, so-called plant factories, for few years. The aim of the experiment was to define a short-day treatment (SD) that harden seedlings to sustain 3 months of cold storage, but does not have adverse effects on growth, morphology, and vitality. The seedlings were subjected to one of the following treatments: (1) 12?h photoperiod + 3 weeks duration; (2) 8?h photoperiod + 3?wk duration; (3) 12?h photoperiod + 5?wk duration; and (4) 8?h photoperiod + 5?wk SD. All the SD treatments yielded healthy seedlings that grew well after the cold storage. The frost hardiness of the seedlings improved when the photoperiod was reduced from 12 to 8?h, and when the SD duration was increased from 3 weeks to 5 weeks, but reducing the photoperiod from 12?h to 8?h caused growth reductions. The root and shoot regrowth after cold storage was highest in seedlings that had received 12?h photoperiod and 5?wk duration. However, 12?h photoperiod and 3?wk duration may be an adequate practice for nurseries that treat multiple crops in their SD facilities.     

4个鲜食葡萄品种组培快繁体系的建立

为加快鲜食葡萄苗木的繁殖速度,提高苗木品质,以鲜食葡萄品种夏黑、红地球、巨峰和玫瑰香为试验材料,通过对无菌外植体的消毒、继代和驯化等环节技术的探究,建立适用于不同鲜食葡萄品种的组培快繁体系。结果表明,以葡萄茎段作为外植体在低浓度(0.3%~0.5%)次氯酸钠溶液中消毒15 min后,接种在MS+0.2 mg·L^-1IBA+1.0 mg·L^-16-BA+0.5 mg·L^-1KT +4.0 mg·L^-1腺嘌呤 +30 g·L^-1蔗糖 +8.2 g·L^-1琼脂的培养基上,成活率达到87.5%;以培养基WPM添加0.2 mg·L^-1 IBA增殖培养兼生根诱导,组培苗生长健壮,生根效果好。采用水培方法炼苗3周后4个品种组培苗移栽成活率均达到100%。综上,完整的基础组培快繁体系可应用于科学研究及工业化大规模生产。本研究为加快鲜食葡萄的繁殖速度、提高苗木质量提供了理论依据。     

育秧基质对水稻秧苗生长与生理特征的影响

[目的]研究育秧基质对水稻秧苗生长与生理特征的影响。[方法]采用盆栽试验,设置了100%基质、75%基质+25%土壤、50%基质+50%土壤、25%基质+75%土壤、100%土壤5个配比处理,测定各处理播种后水稻秧苗成秧率、株高、叶龄、最大叶宽,并测定叶片可溶性糖含量、可溶性蛋白质含量及根系活力。[结果]75%基质+25%土壤处理秧苗生长最佳,其成秧率、株高、叶龄、最大叶宽等均高于其他处理,秧苗综合生理指标也显示75%基质+25%土壤处理优于其他处理。[结论]该研究为水稻育秧机械化及现代农业的发展提供了理论支撑。     

Severity of Xanthomonas axonopodis leaf blight on eucalypt cuttings under different levels of nutrients

Bacterial leaf blight of eucalypt, caused by Xanthomonas axonopodis, occurs mainly in forest nurseries, but also affects young plants in the field. Avoidance of leaf wetness for long periods of time over the whole nursery and using drip irrigation for clonal hedges are, currently, the most effective measures for controlling bacterial leaf blight on eucalypt. However, as these techniques are very costly, alternative management measures are required. We hypothesized that the management of mineral nutrients could reduce disease severity on eucalypts. To examine this hypothesis, rooted cuttings of Eucalyptus urophylla × E. grandis were irrigated with nutrient solutions containing different concentrations of copper (Cu), boron (Bo), potassium (K), calcium (Ca) and nitrogen (N) before inoculation with X. axonopodis 30 days after starting the nutrient solution treatments. Concentration of K higher than that recommended, commonly used in miniclonal hedges, reduced the severity of bacterial leaf blight. However, disease severity increased with an increasing of N/K ratio. The management of mineral nutrition solution, especially K, has great potential for integrated disease management of X. axonopodis in eucalypt nurseries.     

Occurrence and pathogenicity of Phytophthora × cambivora on Prunus laurocerasus in Serbia

Cherry laurel (Prunus laurocerasus) is a native plant species in Serbian forests, but is also widely used for ornamental plantings. Following two extremely wet summers in 2014 and 2015, in spring and summer of 2016 and 2017, numerous cherry laurel plants with symptoms indicative for Phytophthora diseases, like wilting and chlorosis of leaves, dieback and bleeding bark necroses, were recorded in a park in Belgrade and in two ornamental nurseries in central Serbia. From necrotic bark samples and rhizosphere soil, self‐sterile Phytophthora isolates with woolly colonies were obtained. Due to the production of ellipsoid and elongated, non‐papillate sporangia in water and of ornamented oogonia with two‐celled antheridia in mating tests with tester strains of both Phytophthora × cambivora and P. cryptogea, these isolates were identified as P. ×cambivora which was confirmed by ITS sequence analysis. Pathogenicity of P. ×cambivora from cherry laurel (PCCL) was tested by inoculating one‐year‐old seedlings of cherry laurel under the bark. P. ×cambivora from European beech (PCB), and isolates of P. cactorum (CAC), P. cryptogea (CRY), P. plurivora (PLU) and P. ×serendipita (SER) were included as comparison. Three and a half months after inoculation, nine of the twelve plants in PCB, three in PCCL and CAC and two in PLU declined with longitudinal necroses and chlorosis, wilting and premature shedding of leaves. These results demonstrate the ability of P. ×cambivora to infect and cause decline of cherry laurel plants. The particularly high aggressiveness of the P. ×cambivora isolate from beech shows that this pathogen poses a serious risk to cherry laurel in the rare natural communities of cherry laurel and beech in Serbia.