Agroinfection-based high-throughput screening reveals specific recognition of INF elicitins in Solanum

We adapted and optimized the use of the Agrobacterium tumefaciens binary PVX expression system (PVX agroinfection) to screen Solanum plants for response to pathogen elicitors and applied the assay to identify a total of 11 clones of Solanum huancabambense and Solanum microdontum , out of 31 species tested, that respond to the elicitins INF1, INF2A and INF2B of Phytophthora infestans . Prior to this study, response to INF elicitins was only known in Nicotiana spp. within the Solanaceae. The identified S. huancabambense and S. microdontum clones also exhibited hypersensitivity-like cell death following infiltration with purified recombinant INF1, INF2A and INF2B, thereby validating the screening protocol. Comparison of INF elicitin activity revealed that Nicotiana plants responded to significantly lower concentrations than Solanum , suggesting variable levels of sensitivity to INF elicitins. We exploited natural variation in response to INF elicitins in the identified Solanum accessions to evaluate the relationship between INF recognition and late blight resistance. Interestingly, several INF-responsive Solanum plants were susceptible to P. infestans . Also, an S. microdontum  × Solanum tuberosum (potato) population that segregates for INF response was generated but failed to identify a measurable contribution of INF response to resistance. These results suggest that in Solanum , INF elicitins are recognized as general elicitors and do not have a measurable contribution to disease resistance.     

Three new species of deep‐sea Gromia (Protista,Rhizaria) from the bathyal and abyssal Weddell Sea,Antarctica

We describe three new species of the genus Gromia from bathyal and abyssal depths in the Weddell Sea. The new species are characterized by a combination of morphological and molecular criteria. All three species possess a distinct oral capsule and a layer of ‘honeycomb membranes’, which form the inner part of the organic test wall. Both these features are typical of gromiids. Their identification as gromiids is confirmed by analyses of partial small subunit ribosomal DNA (SSU rDNA) gene sequences. Gromia marmorea sp. nov. is a rounded species with a prominent oral capsule and a characteristically mottled appearance. In Gromia melinus sp. nov. , the test surface exhibits a polygonal pattern of ridges, with a layer of clay particles coating the surface between the ridges. Gromia winnetoui sp. nov. represents an elongate morphotype in which the organic test is enclosed within an agglutinated case, a feature previously unknown in gromiids. Phylogenetic analysis using the maximum‐likelihood method revealed that all three species form distinct clades, reflecting the morphological differences among Weddell Sea species, as well as between deep‐water Southern Ocean Gromia and previously described gromiids. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 157 , 451–469.     

Differential Effects of an Intense Wildfire on Survival of Sympatric Snakes

Abstract: We analyzed 16 years of mark-recapture data to investigate whether a wildfire influenced survival of an arboreal ambush-forager (broad-headed snake [Hoplocephalus bungaroides]) and a terrestrial active forager (small-eyed snake Cryptophis nigrescens). We predicted that wildfire would cause direct mortality and reduce subsequent survival of both snake species. Contrary to this prediction, wildfire did not affect abundance of broad-headed snakes, but abundance of small-eyed snakes decreased by 48% after the wildfire. Estimated annual survival of small-eyed snakes was 37% lower after fire (s=0.47, SE=0.07) than before fire (s=0.74, SE=0.05). Prescribed burning may be a suitable tool for creating open habitat mosaics for the endangered broad-headed snake.     

Epiphytic diatoms in two freshwater maritime Antarctic lakes

SUMMARY.

• 1 An ecological study of two small maritime Antarctic lakes on Signy Island, South Orkney Islands, was undertaken from January 1986 to March 1987. Analysis of diatom counts from the lakes provided examples of oligotrophic and mesotrophic ecosystems.
• 2 A diverse community of 104 epiphytic taxa was identified. Twenty-eight taxa had a percentage abundance greater than 1% in both lakes. Distinctive dominant taxa were identified from each lake.
• 3 A variety of ordination techniques was performed on the abundance data and a principal components analysis demonstrated differences in the diatom assemblages between the two lakes. Clear separations of sites and species were evident between the lakes, and accounted for the greatest percentage variance.
• 4 Species composition varied with depth within each lake and was also important in influencing changes in assemblage composition between sites.
• 5 A redundancy analysis indicated that species composition was correlated to concentrations of nitrogen and phosphorus but the total variance accounted for by the four physical and chemical factors measured was low (24%).

     

Spatial variations in the water quality of Lough Erne, Northern Ireland, on the basis of surface sediment diatom analysis

SUMMARY. 1. Constrained cluster analysis of thirty-five surface sediment diatom assemblages shows that Lough Erne, a complex multi-basin lake in Northern Ireland, can be sub-divided into four main zones.
2. All areas of the lake system have planktonic diatoms typical of eutrophic lakes but the lack of small Stephanodiscus species in zone 4 suggests that this area of the system is least productive.
3. Surface sediment diatom assemblages can be used to assess spatial variations in complex lake systems and can thereby be used as a guide to the choice of sites for water quality monitoring and sediment coring.     

Trophic level asynchrony in rates of phenological change for marine,freshwater and terrestrial environments

Recent changes in the seasonal timing (phenology) of familiar biological events have been one of the most conspicuous signs of climate change. However, the lack of a standardized approach to analysing change has hampered assessment of consistency in such changes among different taxa and trophic levels and across freshwater, terrestrial and marine environments. We present a standardized assessment of 25 532 rates of phenological change for 726 UK terrestrial, freshwater and marine taxa. The majority of spring and summer events have advanced, and more rapidly than previously documented. Such consistency is indicative of shared large scale drivers. Furthermore, average rates of change have accelerated in a way that is consistent with observed warming trends. Less coherent patterns in some groups of organisms point to the agency of more local scale processes and multiple drivers. For the first time we show a broad scale signal of differential phenological change among trophic levels; across environments advances in timing were slowest for secondary consumers, thus heightening the potential risk of temporal mismatch in key trophic interactions. If current patterns and rates of phenological change are indicative of future trends, future climate warming may exacerbate trophic mismatching, further disrupting the functioning, persistence and resilience of many ecosystems and having a major impact on ecosystem services.     

Survival of Wood Duck Ducklings and Broods in Mississippi and Alabama

ABSTRACT Although North American wood ducks (Aix sponsa) are well-studied throughout their range, researchers know little about demographic and environmental factors influencing survival of ducklings and broods, which is necessary information for population management. We studied radiomarked female and duckling wood ducks that used nest boxes and palustrine wetlands at Noxubee National Wildlife Refuge (NNWR) in Mississippi, USA, in 1996–1999, and riverine wetlands of the Tennessee-Tombigbee Rivers and Waterway (TTRW) system in Alabama in 1998–1999. We estimated survival of ducklings and broods and evaluated potentially important predictors of duckling survival, including age and body mass of brood-rearing females, hatch date of ducklings, duckling mass, brood size at nest departure, inter-day travel distance by ducklings, site and habitat use, and daily minimum air temperature and precipitation. At NNWR, survival of 300 radiomarked ducklings ranged from 0.15 (95% CI = 0.04-0.27) to 0.24 (95% CI = 0.13-0.38) and was 0.21 (95% CI = 0.15-0.28) for 1996–1999. Our overall estimate of brood survival was 0.64 (n = 91; 95% CI = 0.54-0.73). At TTRW, survival of 129 radiomarked ducklings was 0.29 in 1998 (95% CI = 0.20-0.41) and 1999 (95% CI = 0.13-0.45) and was 0.29 (95% CI = 0.20-0.40) for 1998–1999. Our overall estimate of brood survival was 0.71 (n = 38; 95% CI = 0.56-0.85). At NNWR, models that included all predictor variables best explained variation in duckling survival. Akaike weight (w_i) for the best model was 0.81, suggesting it was superior to other models (<0.01 < w_i < 0.18). We detected 4 competing models for duckling survival at TTRW. Inter-day distance traveled by ducklings was important as this variable appeared in all 4 models; duckling survival was positively related to this variable. Patterns of habitat-related survival were similar at both study areas. Ducklings in broods that used scrub-shrub habitats disjunct from wetlands containing aggregations of nest boxes had greater survival probabilities than birds remaining in wetlands with such nest structures. Managers may increase local wood duck recruitment by promoting availability of suitable brood habitats (e.g., scrub-shrub wetlands) without aggregations of nest boxes that may attract predators and by dispersing nest boxes amid or adjacent to these habitats. We did not determine an optimal density of nest boxes relative to local or regional population goals, which remains important research and conservation needs.     

The Effects of One-Off Ivory Sales on Elephant Mortality

ABSTRACT We revisited the debate about whether the 1999 one-off sale of ivory promoted elephant (Loxodonta africana) poaching in Africa. Complementing earlier work based on ivory seizure data, we considered data on elephant mortality in Zimbabwe and Kenya. Our findings present a mixed picture. At the local level there was some evidence that the one-off sale resulted in extra elephant killing, but this effect was relatively small (and probably short-lived). Although the data were too scanty to draw strong conclusions, decision-making about elephant management and the ivory trade has to continue and will necessarily be based on imperfect information for a long time to come. Our findings suggest that further experimenting with one-off sales may be beneficial from a conservation and development perspective.     

The Onset of Germination Ability in Developing Wheat

The ability of primary wheat grains (cv. Sappo) to germinatewas determined at different times from anthesis. Fresh, prematurelyharvested grains germinated best at low temperatures (<10°C). The temperature range over which appreciable germinationtook place broadened and the maximum percentage germinationachieved increased with lengthening time between anthesis andharvest. Chilling and exogenous applications of GA₃ each affectedthe rate of germination and the maximum percentage germinationof grains in their own ways. The results are discussed in relationto the identification of ‘dormancy’ in wheat grains.     

The Conservation Status of Hong Kong's Tree Flora

1IntroductionHongKongliesonthesouthcoastofChinabetweenlatitudes22?9'-22?TNandlon-gitudesl13?2'Nl14?0'E.ItconsistsofasectionoftheChinesemainland(KowloonandtheNewTerritories,782km2)andnumerousislands,ofwhichthelargestareLantauIsland(142km2)andHongKongIsland(78km2).Thetotalareais1076km2.Thetopographyisextremelyrugged,reaching957matthehighestpoint,TaiMoShah,intheNewTerrito-ries.HongKong'spopulationof6millionpeopleisconcentratedonthelimitednaturalflatland,whichhasbeenextendedbycoastalrecla…