Stramenopile Microorganisms Associated with the Massive Coral Favia sp.

ABSTRACT. The surfaces of massive corals of the genus Favia from Eilat, Red Sea, and from Heron Island, Great Barrier Reef, are covered by a layer of eukaryotic microorganisms. These microorganisms are embedded in the coral mucus and tissue. In the Gulf of Eilat, the prevalence of corals covered by patches of eukaryotic microorganisms was positively correlated with a decrease in water temperatures (from 25–28 °C in the summer to 20–23 °C in winter). Comparisons carried out using transmission and scanning electron microscopy showed morphological similarities between the microorganisms from the two geographically distant reefs. The microorganisms found on and in the tissues were approximately 5–15 μm in diameter, surrounded by scales in their cell wall, contained a nucleus, and included unique auto‐florescent coccoid bodies of approximately 1 μm. Such morphological characters suggested that these microorganisms are stramenopile protists and in particular thraustochytrids. Molecular analysis, carried out using specific primers for stramenopile 18S rRNA genes, revealed that 90% (111/123) of the clones in the gene libraries were from the Thraustochytriidae. The dominant genera in this family were Aplanochytrium sp., Thraustochytrium sp., and Labyrinthuloides sp. Ten stramenopile strains were isolated and cultured from the corals. Some strains showed ≥97% similarity to clones derived from libraries of mucus‐associated microorganisms retrieved directly from these corals. Fatty acid characterization of one of the prevalent strains revealed a high percentage of polyunsaturated fatty acids, including omega‐3. The possible association of these stramenopiles in the coral holobiont appeared to be a positive one.     

Control by imazalil of fruit storage rots caused by Alternaria alternata

The fungicide imazalil has potential value for controlling post-harvest diseases caused by Alternaria alternata in pears, apples and persimmons. Imazalil was active in vitro on germination and hyphal growth (ED₅₀) at 1.4 and 0.5 μg/ml, respectively. Protectant action of the fungicide lasted only 1 day after treatment. At 1000 μg/ml the fungicide inhibited development of Alternaria rot in inoculated apples at 0 °C and in naturally infected pears and persimmons at–1 °C.     

A method for pre-harvest assessment of latent infections in fruits

A method was developed for the assessment of latent infections of Alternaria alternata in mango fruits. Fruit discs were sampled and assayed for fungal contamination under suitable growth conditions. By this method it was possible to evaluate the percentage of infections and the relative surface infected by Alternaria in mango fruits before harvest. The percentage of infections increased during the growing season but fungicide treatments prevented this increase. A significant positive correlation was found between the relative surface infected by latent Alternaria at harvest time and the incidence of black spots that developed on the fruit during storage.     

Biological invasions and scientific objectivity: Reply to Cassey et al. (2005)

Abstract We disagree with the assertion that recent human‐caused invasions differ substantially from historic natural invasions in their magnitudes and impacts on ecological processes. The position that exotic species are inherently ‘bad’ and should be eradicated is an ethical judgement, usually based on the naturalist fallacy or xenophobic prejudice; it is not a scientific judgement. The role of scientists in studying invasive species should be to gather, interpret and communicate information as accurately and objectively as possible.     

Differential Effects of the Parental Photothermal Environment on Development of Dormancy in Caryopses of Aegilops Kotschyi

Aegilops Kotschyi Boiss. plants produce three florets per spikelet(of which the terminal floret is commonly sterile) and exhibitphysiological heterocarpy in the two caryopses which developin each spikelet. Germinability of the basal caryopsis, butnot of the upper one, was subject to environmental influencesto which the parent plant was exposed during its development.Basal caryopses produced by plants grown at low temperature,or in 16-h photoperiods, were more dormant than when producedby plants grown at higher temperature, or in 8-h photo-periods.Germinability of the upper caryopses was equally high in allcases and independent of the parental environment. The photoperiodeffects on germinability were exerted after anthesis. Matureweight of both basal and upper caryopses was higher when producedon plants grown at low temperature, or transferred from 16-hto 8-h photopenods at emergence of the flag leaf     

Agroclimatic conditions in Europe under climate change

To date, projections of European crop yields under climate change have been based almost entirely on the outputs of crop‐growth models. While this strategy can provide good estimates of the effects of climatic factors, soil conditions and management on crop yield, these models usually do not capture all of the important aspects related to crop management, or the relevant environmental factors. Moreover, crop‐simulation studies often have severe limitations with respect to the number of crops covered or the spatial extent. The present study, based on agroclimatic indices, provides a general picture of agroclimatic conditions in western and central Europe (study area lays between 8.5°W–27°E and 37–63.5°N), which allows for a more general assessment of climate‐change impacts. The results obtained from the analysis of data from 86 different sites were clustered according to an environmental stratification of Europe. The analysis was carried for the baseline (1971–2000) and future climate conditions (time horizons of 2030, 2050 and with a global temperature increase of 5 °C) based on outputs of three global circulation models. For many environmental zones, there were clear signs of deteriorating agroclimatic condition in terms of increased drought stress and shortening of the active growing season, which in some regions become increasingly squeezed between a cold winter and a hot summer. For most zones the projections show a marked need for adaptive measures to either increase soil water availability or drought resistance of crops. This study concludes that rainfed agriculture is likely to face more climate‐related risks, although the analyzed agroclimatic indicators will probably remain at a level that should permit rainfed production. However, results suggests that there is a risk of increasing number of extremely unfavorable years in many climate zones, which might result in higher interannual yield variability and constitute a challenge for proper crop management.