Introductions of non-native plant pathogens into Great Britain, 1970–2004

An analysis of records of plant pathogens first identified in Great Britain from 1970 to 2004 (inclusive) was undertaken to determine the numbers of new species that have become established over time. Results show that the numbers of newly recorded pathogens have not varied significantly. Of the 234 pathogens recorded for the first time between 1970 and 2004, 157 were fungi, 27 were oomycetes, 26 were viruses, 23 were bacteria, and one was a phytoplasma. Approximately 53% of pathogens were found on ornamental crops, 16% on horticultural crops, 15% on wild native species, 12% on agricultural crops, 2% on pasture plants and 2% on exotic forestry tree species. Where the origin of introductions was known or strongly suspected, 47% came from the Netherlands. About 38% of newly recorded pathogens with information on the location of first record were discovered in the South East region of England. Plant Pathologists regarded 19% of all new pathogens as important because of actual or potential economic/environmental losses. The results indicate that the numbers of new or important pathogens establishing in recent years are not increasing and that most new findings are associated with ornamental plants.     

Artificial Reefs, the Attraction-production Issue, and Density Dependence in Marine Ornamental Fishes

Artificial reefs may provide a useful tool to enhance production of marine ornamentals and to divert detrimental harvesting activities from sensitive natural habitat. The efficacy of this strategy depends, in part, on the extent to which artificial reefs contribute to new production (vs. attract fishes from natural habitat) and therefore benefit harvested populations on a local and regional basis. Here the attraction and production hypotheses and their application to marine ornamentals are presented. Specifically, it is discussed how the strength and timing of density dependence can affect the response of fish population dynamics to artificial reefs. In addition to this discussion, examples of density dependence in marine ornamentals and related reef fishes are provided. Based on this information, a simple conceptual model is presented to clarify the role of density dependence, and this is followed by a discussion on the use of artificial reefs in the management and production of marine ornamentals. Finally, unresolved scientific issues that remain to be addressed are provided.     

Year‐round natural spawning,early development,and the effects of temperature,salinity and prey density on captive ornate goby Istigobius ornatus (Rüppell, 1830) larval survival

Natural spawning, early development and larviculture of the ornate goby Istigobius ornatus in captivity were studied for the first time. I. ornatus spawned 46 times from 31 October 2013 to 31 October 2014. Fecundity ranged from 246 to 10,214 eggs per clutch, with an average hatching rate of 77.8% ± 9.9% (M ± SEM). Fertilized eggs (1.31–1.54 × 0.46–0.50 mm in diameter) were adhesive demersal and oval‐shaped. Embryonic development lasted 84 hr at 27.5 ± 0.5°C. Newly hatched larvae [2.12 ± 0.04 mm in total length (TL)] transformed to the juvenile stage completely when TL was 7.79 mm. Effects of different water temperatures (24, 28 and 32°C) and salinities (10, 15, 20, 25, 30, 35 and 40 g/L) on per cent survivals (%) and survival activity indices (SAIs) were tested. Survival was not significantly different under different temperatures; SAIs was significantly higher at 28°C. Larvae showed the significantly higher survival and SAIs at salinities 10–30 g/L than at 35 and 40 g/L. Effect of different prey densities on survival was significantly higher in 7 days post hatch larvae fed 20 and 30 rotifers/ml. These findings could guide future programs in captive breeding technology development and commercial production of other marine ornamental gobies.     

混种3种观赏植物对白三叶铅积累的影响

为了研究铅污染条件下对白三叶植物修复效率的影响,通过盆栽和小区试验,将一串红、翠菊、德国鸢尾分别与白三叶混种,研究不同混种方式对白三叶生物量及铅积累的影响。结果表明:与白三叶单种相比,混种德国鸢尾提高了白三叶单株地上部分生物量和整株生物量,混种一串红、翠菊则降低了白三叶单株地上部分生物量和整株生物量;就混种系统而言,各个混种处理的植物总生物量均介于混种的2种植物单种之间。混种一串红、翠菊、德国鸢尾均提高了白三叶地上部分铅含量,盆栽试验分别较白三叶单种提高了11.39%,17.88%,42.18%;小区试验分别较白三叶单种提高了2.64%,13.22%,23.94%。白三叶混种德国鸢尾的地上部分铅积累总量高于各自单种,其余混种处理均介于混种的2种植物单种之间。小区试验中,白三叶混种德国鸢尾的单位面积地上部分铅积累总量最高,达242.777mg/m2,较白三叶单种提高了371.83%,较德国鸢尾单种提高了8.38%;白三叶混种德国鸢尾的土壤重金属铅去除率最高,达15.11%,比白三叶单种提高了326.84%,比德国鸢尾单种提高了10.70%。因此,白三叶混种德国鸢尾的铅提取效果表现最好,能够用于铅污染土壤的修复。     

The effects of dietary HUFA level on flame angelfish (Centropyge loriculus) spawning,egg quality and early larval characteristics

This study was conducted to determine the effects of dietary highly unsaturated fatty acids (HUFA) on flame angelfish (Centropyge loriculus) reproduction, and egg and larval quality. In the experiment, formulated diets containing 1.8, 2.9 or 3.6% n‐3 HUFA were fed to flame angelfish broodstock (n = 4) for 5 months. Mean fecundity (daily egg production), egg fertilization rates and embryo viability were used as indicators of egg quality. In addition, mean egg diameter, oil globule diameter, per cent hatch, larval size at hatch, per cent survival to yolk exhaustion and larval size at yolk exhaustion were recorded for each treatment. Flame angelfish fed the diet containing 3.6% n‐3 HUFA exhibited significantly increased fecundity, fertilization rates and embryo viability than fish that were fed the other two formulated diets. Egg diameter, egg oil globule diameter, larval size at hatch, larval survival to yolk exhaustion and larval size at yolk exhaustion from the 3.6% n‐3 HUFA broodstock treatment group were not significantly different from those derived from the Control broodstock treatment. These data revealed that flame angelfish egg quality could respond rapidly (within weeks) to maternal dietary changes. Results from this study further support that dietary HUFA composition can significantly affect broodstock reproductive performance as well as subsequent performance of eggs and larvae.     

Are Acartia tonsa cold‐stored eggs a suitable food source for the marine ornamental species Amphiprion polymnus? A feeding study

Copepods are the natural food items for marine fish larvae but are still difficult to be cultured on a continuous basis. Therefore, suitable storage techniques for copepod subitaneous eggs are of great interest. Cold‐stored copepod embryos still develop and retain a physiological activity during the cold storage period. As a consequence, their nutritional quality may change over the time of storage with these changes possibly affecting both eggs viability and larval fish survival and development. In this study, the clownfish, Amphiprion polymnus, was used as an experimental model to compare, for the first time, the effects of diets based on enriched rotifers and Artemia (control), Acartia tonsa copepods of a continuous culture and A. tonsa originated from 6 months cold‐stored eggs. The effects of the different diets were tested through morphometric, molecular and biochemical approach. This study demonstrated that after a 6 months cold storage period, the quality of copepods obtained from those eggs was suboptimal for A. polymnus larval rearing. In fact, larvae fed those copepods showed lower growth and survival performances respect to the other experimental groups.     

SYNTHETIC SOIL AGGREGATES AS A POTTING MEDIUM FOR ORNAMENTAL PLANT PRODUCTION

Synthetic aggregates (SA) were developed as alternative potting media for ornamental plant production. Four different types of SA were developed from low productive acidic soil and paper waste with adding different types of compost amendments. Compost amendments used in the experiment were cattle manure compost, chicken manure compost, and leaf manure compost. Popular ornamental plant french marigold (Tagetes patula) was used in this experiment. SA with different compost amendments gave considerable physical and chemical parameters compared to commercial zeolite media. Moreover, plant grown in SA media showed better growth and nutritional parameters compared to plant grown in zeolite media. The plant height, number of flowers per plant, shoot fresh weight, shoot dry weight, root length, root fresh weight and root dry weight obtained from three different compost based SA were increased by in the ranges of 8.14--14.41%, 5.66--9.46%, 25.52--31.47%, 9.44--16.13%, 6.14--9.23%, 2.40--8.47% and 8.85--17.05%, respectively, compared to zeolite control.     

13种常用室内观赏植物对甲醛净化效果

【研究目的】给人们生活提供有效的降低室内甲醛污染的方法;【方法】选用13种常用室内观赏植物,将盆土与茎叶部分隔开,放入自行研制的甲醛熏蒸箱中,对植物进行熏蒸实验,测得熏蒸前后甲醛的变化量和植物叶面积,以单位叶面积甲醛减少量来比较植物间吸纳甲醛能力的大小并排序。【结果与结论】结果显示,合果芋等吸纳甲醛的能力较强,而芦荟等吸纳甲醛的能力较弱。     

Two new effective semiselective crystal violet pectate media for isolation of Pectobacterium and Dickeya

Pectolytic bacteria, including Pectobacterium spp. and Dickeya spp., are best isolated on crystal violet pectate (CVP), a semiselective medium containing pectin. The source of pectin is essential, because pectolytic bacteria are not able to degrade all of them. The aims of this study were to identify a new pectin source and to perfect formulations of semiselective CVP media to isolate the pectolytic bacteria Pectobacterium spp. and Dickeya spp. from different environmental compartments (plants, soil and water). The AG366 pectin, selected after screening six different formulations, was incorporated into single‐layer (SL‐CVP_AG366) and double‐layer (DL‐CVP_AG366) CVP media. Both media were compared with those based on Bulmer, Sigma‐Aldrich and Slendid‐Burger pectins, using 39 Pectobacterium and Dickeya strains. All strains formed deep cavities on AG366‐CVPs, whereas nine did not produce cavities on Bulmer or Sigma‐Aldrich media. Recovery rates were similar on DL‐CVP_AG366, Sigma‐Aldrich and Bulmer CVPs for a given taxon, and did not differ significantly between SL‐ and DL‐CVP_AG366. Pectolytic bacteria were successfully isolated on both media from field samples of diseased potatoes, carrots, tobacco, onions, radishes and ornamentals. AG366 is thus a high‐performance pectin source for the elaboration of CVP media suitable to isolate Dickeya and Pectobacterium. It is also efficient for enrichment purposes in liquid medium. The validation of AG366 as an improved source of pectin to recover the polyphagous Pectobacterium and Dickeya in different environmental compartments is essential given the current worldwide emergence and recrudescence of these bacteria.     

Facing Rose rosette virus: A risk to European rose cultivation

Roses (Rosa) are one of the most valuable ornamental flowering shrubs around the globe. They are susceptible to numerous pathogens that require management, increasing the cost of cultivation. Rose rosette virus (RRV; genus Emaravirus) is a devastating virus that has been spreading since the 1940s in the United States and Canada. It is an emerging risk to European and worldwide rose cultivation, causing symptoms such as witches' broom, malformations, excessive thorn production, and eventually plant death. RRV is transmitted by the eriophyid mite Phyllocoptes fructiphilus and by grafting. Research is being undertaken to understand RRV and to find control measures and resistant cultivars, as they are not currently available. Early detection of the disease is the key to prevent the establishment and spread of RRV and its vector. Different molecular and serological diagnostic methods have been designed and implemented, including ELISA, RT-PCR, RT-qPCR, LAMP, and high-throughput sequencing. RRV infected plants can remain symptomless for long periods, so these diagnostic assays are necessary in conjunction with visual assessment to facilitate early detection. Significant social, economic, and environmental impacts are expected if RRV and its vector establish and spread in Europe. Rose trade between countries is the most likely pathway of introduction of RRV into Europe. In this review we describe current knowledge about RRV, the molecular and serological methods available for the detection of this virus, pathways to entry, and the possible impact if it establishes and spreads in Europe.