Oviposition strategies of conifer seed chalcids in relation to host phenology

Insects are considered the most important predators of seed cones, the female reproductive structures of conifers, prior to seed dispersal. Slightly more than 100 genera of insects are known to parasitize conifer seed cones. The most diverse (i.e., number of species) of these genera is Megastigmus (Hymenoptera: Torymidae), which comprises many important seed pests of native and exotic conifers. Seed chalcids, Megastigmus spp., lay eggs inside the developing ovules of host conifers and, until recently, oviposition was believed to occur only in fertilized ovules. Ovule development begins just after pollination, but stops if cells are not fertilized. The morphological stage of cone development at the time of oviposition by seed chalcids has been established for many species; however, knowledge of ovule development at that time has been documented for only one species, M. spermotrophus. Megastigmus spermotrophus oviposits in Douglas-fir ovules after pollination but before fertilization. Unlike the unfertilized ovules, those containing a M. spermotrophus larva continue to develop, whether fertilized or not, stressing the need to broaden our understanding of the insect–plant interactions for this entire genus. To achieve this task, we reviewed the scientific literature and assembled information pertaining to the timing of oviposition and to the pollination and fertilization periods of their respective host(s). More specifically, we were searching for circumstantial evidence that other species of Megastigmus associated with conifers could behave (i.e., oviposit before ovule fertilization) and impact on female gametophyte (i.e., prevent abortion) like M. spermotrophus. The evidence from our compilation suggests that seed chalcids infesting Pinaceae may also oviposit before ovule fertilization, just like M. spermotrophus, whereas those infesting Cupressaceae seemingly oviposit after ovule fertilization. Based on this evidence, we hypothesize that all species of Megastigmus associated with Pinaceae can oviposit in unfertilized ovules, whereas those exploiting Cupressaceae cannot, and thus oviposit only in already fully developed fertilized seeds. Furthermore, we predict that the presence of a larva in unfertilized ovules of all Pinaceae will influence the development of the female gametophyte by preventing its abortion. This influence on the Pinaceae can be interpreted as an ability to parasitize any of the potential seeds present in a seed cone, and as such represents a much more efficient oviposition strategy than searching and locating only fertilized seeds. Concomitantly, this ability has likely led to an overestimation of the impact of the species of seed chalcid infesting Pinaceae on seed production.     

急需资金的世界环境日

如果日历上有一个日子，是用来鼓励全世界人民摈弃政治行为，只关注全球环境状况，那它就是世界环境日。不幸的是，每年的这一天，不用大张旗鼓地宣传，人们也已经了解世界环境形势岌岌可危。而事实上，今年世界环境日可能标志着国际环境保护资金的撤离。     

Monogamy in a new species of wild guinea pigs (Galea sp.)

A new species of wild guinea pigs from Bolivia was recently discovered: Galea sp. So far no data are available concerning its social and mating systems. We therefore investigated behavioural compatibility, sexual dimorphism, paternity in a male-competing situation, testicular and epididymal size, and sperm morphology and motility. The results showed a complete intrasexual and moderate intersexual behavioural incompatibility between unfamiliar animals, a reversed sexual dimorphism with females larger than males, and litters always fathered by single males. Furthermore, both the reproductive organ weights and the percentage of motile sperm and sperm with intact acrosomes were significantly lower compared with the promiscuous congeneric Galea musteloides. In summary, these data strongly suggest a monogamous social and mating system for the recently discovered Galea sp.     

Differential effect of cadmium and mercury on growth and metabolism of Solanum melongena L. seedlings

The present investigation reports the results of the effect of cadmium and mercury individually on seed germination, seedling growth, number of lateral roots, fresh and dry weights and seedling metabolism in Solanum melongena. Effect of different concentrations of these two heavy metals (Cadmium--50, 100, 300, 500, 700, 1000, 3000, 5000, 7000 and 9000 ppm and Mercury--5, 10, 15, 20, 25, 30, 35, 40, 45 and 50 ppm) and durations for 6, 12 and 24 h were employed for all seedling parameters of brinjal. Both Cd and Hg showed drastic effects at high concentrations and longer duration with regard to seedling growth and metabolism.     

Inorganic nutrient utilisation by "adapted" Pseudomonas putida strain used in the bioremediation of agricultural soil polluted with crude petroleum

Garden soil samples polluted with crude petroleum were bioremediated by inorganic nutrient monitoring with appropriate adjustment and inoculation with crude oil-adapted strain of Pseudomonasputida (PP) isolated from oil-impacted soils. Soil samples without PP inoculation served as the control samples to compare the abilities of the native soil microflora with the adapted PP strain in biodegrading crude oil pollutant. In the experimental samples, oil concentration and all the inorganic nutrient sources tested decreased more rapidly with a proportional increase in the population densities of both PP and the native soil microflora than were observed in the control samples. This trend was particularly strong for PO4(3-) and NO3- which eventually became limiting both in all the experimental samples and in some control samples. Inoculation of crude oil-impacted agricultural soils by oil -adapted PP strain with nutrient monitoring and adjustment can be effective as bioremediation methods of agricultural land upon pollution with petroleum or petroleum products.     

个人计算机在工业环境管理中的应用

本文评述了个人计算机在工业环境管理中的一些新应用。这些包括计算密集型应用、面向情报的应用和图形处理应用,以及涉及实时通讯和控制的应用。文中提到一些软件产品。     

Profiles of acid and alkaline phosphatases in the prawn Macrobrachium malcolmsonii exposed to endosulfan

The present study was performed to determine the toxic effects of endosulfan on the quantitative and qualitative aspects of acid and alkaline phosphatases (ACP and ALP) in Macrobrachium malcolmsonii. Intermoult juvenile prawns were exposed to 32.0 ng/l of endosulfan for a period of 21 days. Samples were taken from the hemolymph, hepatopancreas, gills and muscle of test prawns on the 21st day. The content of ACP and ALP in the hepatopancreas of test prawns were found to be higher in comparison to respective controls. The levels of these enzymes in the hemolymph, gills and muscle of test prawns were found to be lower than in the same tissues of controls. In non-denaturing PAGE, phosphatases appeared as white bands. The intensity of white bands in the hepatopancreas of test prawns were found to be higher when compared to controls. In the hemolymph, gills and muscle of test prawns, the intensity of white bands were found to be lower in comparison to controls. The results of the present study suggest that endosulfan affects the quantity and quality of ACP and ALP in the tissues of M. malcolmsonii.     

Effects of Hg and Cu on hemocytes-mediated functions in the prawn,Macrobrachium malcolmsonii

Sublethal effects of Hg (9.6, 14.5 and 24.1 microg/l) and Cu (60.5, 90.8 and 150.5 microg/l) on the hemocytes-mediated functions in the juveniles of the economically important freshwater prawns, Macrobrachium malcolmsonii were investigated. The population of total hemocytes, percentile phagocytosis and superoxide anion production were found to be increased in test prawns exposed to the lowest sublethal concentration of these two metals in comparison to controls. This indicates the fact that a mechanism of host-defence was in an active state to encounter metal toxicity. The total hemocytes population, percentile phagocytosis and superoxide anion production were found to be decreased in test prawns exposed to intermediate as well as the highest sublethal concentrations of Hg and Cu when compared with controls. This suggests that high concentrations of both Hg and Cu have inhibitory effects on the immune functions of the hemocytes in the prawn, M. malcolmsonii.     

Recent sedimentary history of anthropogenic impacts on the Culiacan River Estuary,northwestern Mexico: geochemical evidence from organic matter and nutrients

210Pb geochronology and sediment profiles of carbon, phosphorus and nitrogen were used to study time dependent changes in nutrients fluxes to Culiacan River Estuary. Results indicate that the release of urban sewage and agriculture wastes transported through Culiacan River has produced historically increased carbon, phosphorus and nitrogen fluxes to the study area. C:N:P elemental ratios showed that increments in the nutrients input begins simultaneously for C, N and P in 1948 with the clearing of the catchment for agriculture; although excess of nutrients input increased most importantly around the 1970s to roughly follow the rapidly growing population of Culiacan City. C/N ratios, delta13C and delta15N suggested that nutrient enrichment is mostly influenced by sewage delivered through Culiacan River.