Physiological interaction model of sunflower plant with its nutrient medium during ontogenesis

A study was conducted with sunflower plants (Helianthus annuus, L.) cv. Peredovik in field experiments, one of which included 9 NPK-fertilizer treatments. The intensity of uptake,i.e. the quantity (mg) of nutrient taken up for the accumulation of 1 g dry matter/day, the concentrations of all essential elements in the plant organ tissues and their distribution among above-ground organs, by stages of development, were investigated. The results have revealed the inherent physiological system responsible for the uptake intensity of individual elements, as well as the simultaneous uptake and distribution of all essential elements of the root nutrition by the shoots, throughout the life cycle of the plant.     

A quantitative estimation of sequential foliage development and fertility inDryopteris crassirhizoma

The foliage development ofDryopteris crassirhizoma Nakai was quantitatively estimated by measurements of shape and size of leaves from different developmental stages of sporophytes, to lead to an understanding of the life history characteristics of the species. The number of midrib branches (NV, number of veins) of the leaf corresponds to the leaf-shape complexity (DI, dissection index; shape complexity from a circle) and length of leafblade (BL). Some quantitative characters, such as leaf uniformity (decrease in NV variation), changes in shape and increase in number of leaves, vary progressively during foliage formation. The sequence of foliage development can be quantified using the parameter NV: for example, 15-NV for leaf uniformity, 30-NV for leaf-shape change from triangular to oblanceolate, 60-NV for increase in leaf number and leaf fertility in the course of sporophyte ontogeny. Contribution No. 3297 from the Institute of Low Temperature Science, Hokkaido University.     

Biology and epidemics of Candidatus Liberibacter species,psyllid‐transmitted plant‐pathogenic bacteria

Candidatus Liberibacter species are Gram‐negative bacteria that live as phloem‐limited obligate parasites in plants, and are associated with several plant diseases. These bacteria are transmitted by insects called psyllids, or jumping plant lice, which feed on plant phloem sap. Citrus huanglongbing (yellow shoot) or citrus greening disease is associated with three different species of Ca. Liberibacter – Ca. L. asiaticus, Ca. L. africanus and Ca. L. americanus – all originally found on different continents. Ca. L. asiaticus is the most severe pathogen, spread by Asian citrus psyllid Diaphorina citri and causing devastating epidemics in several countries. Ca. L. africanus occurs in Africa where it is spread by the African citrus psyllid Trioza erytreae. Ca. Liberibacter solanacearum is associated with diseases in several solanaceous plants, and transmitted by potato psyllid Bactericera cockerelli. Zebra chip disease is causing large damage in potato crops in North America. In Europe Ca. Liberibacter solanacearum is associated with diseases of the Apiaceae family of plants, carrot and celery, and transmitted by psyllids Trioza apicalis and Bactericera trigonica. When Ca. Liberibacter is suspected as the disease agent, the diagnosis is confirmed by DNA‐based detection methods. Ca. Liberibacter‐associated plant diseases can be controlled by using healthy plant propagation material, eradicating symptomatic plants, and by controlling the psyllid populations spreading the disease.     

MOLECULAR PHYLOGENETIC ANALYSIS OF LIFE-HISTORY EVOLUTION IN ASTERINID STARFISH

We analyzed phylogenetic relationships among 12 nominal species of starfish in the genera Patiriella and Asterina (Order Valvatida, Family Asterinidae), based on complete sequences for a mitochondrial protein coding gene (cytochrome oxidase subunit I) and five mitochondrial transfer RNA genes (alanine, leucine, asparagine, glutamine, and proline) (1923 bp total). The resulting phylogeny was used to test a series of hypotheses about the evolution of life-history traits. (1) A complex, feeding, planktonic larva is probably ancestral for these starfish, but this is not the most parsimonious reconstruction of ancestral larval states. (2) The feeding larval form was lost at least four times among these species, and three of these losses occurred among members of a single clade. (3) Small adult size evolved before both cases of hermaphroditism and viviparous brooding, but viviparity was not always preceded by an intermediate form of external brooding. (4) An ordered transformation series from feeding planktonic development to viviparous brooding has been predicted for starfish, but we could not find an example of this transformation series. (5) Viviparity evolved recently (< 2 Mya). (6) Both species selection and transformation of lineages may have contributed to the accumulation of species with nonfeeding development among these starfish. (7) Neither Asterina nor Patiriella are monophyletic genera. Larval forms and life-history traits of these starfish have evolved freely under no obvious constraints, contrary to the widely assumed evolutionary conservatism of early development.     

Are there Atlantic salmon in the River Tambre?

Genetic variability and assignment analyses demonstrate that the 60 returning adult salmon to the Tambre River in 2005 were not the product of an incipient wild population, but the result of straying from a neighbouring river.     

Success of embryonic development of reciprocal hybrids of bream Abramis brama (L.) and white bream Blicca bjoerkna (L.)

Success of embryonic development of reciprocal hybrids of bream Abramis brama and white bream Blicca bjoerkna was tested under laboratory conditions. Fertilization and embryonic development success of hybrids until hatching was high and comparable to that of pure species.     

Eimeria dispersa and Eimeria gallopavonis: Infectivity, Survival, and Development in Primary Chicken and Turkey Kidney Cell Cultures

SYNOPSIS. Eimeria dispersa (turkey strain) and Eimeria gallopavonis sporozoites were inoculated into primary cultures of chicken kidney (CK) and turkey kidney (TK) cells. Eimeria dispersa sporozoites were more infective in either cell type than those of E. gallopavonis : at 4 hr, the percentage of infection was 67-98 for E. dispersa but only 23-56 for E. gallopavonis . E. dispersa also survived better in culture: at 2 days, losses of E. dispersa in both cell types were only 4-19%, whereas losses of E. gallopavonis were 35-47% in TK cells and 60–95% in CK cells. However, E. gallopavonis developed further than E. dispersa . Location and increase in numbers of intracellular stages at 4 days indicated that E. dispersa proceeded through 2 schizogonic generations before development stopped.     

Patterns of reproduction and development of selected resident teleosts of Florida salt marshes

A wide variety of teleost fishes occur in tidal marshes of Atlantic and Gulf coasts of Florida, few of which breed in these habitats or remain there for extended periods of time. A significant fraction of teleosts that do so are members of one of five families. Eleven representative species belonging to these families, whose reproduction and development are considered here, include: Adinia xenica, Fundulus confluentus, F. grandis and F. similis (Fundulidae); Cyprinodon variegatus, Floridichthys carpio and Jordanella floridae (Cyprinodontidae); Gambusia holbrooki and Poecilia latipinna (Poeciliidae); Mugil cephalus (Mugilidae); and Dormitator maculatus (Eleotridae). Spawning or birth locations, patterns of growth and development, times of use of the salt marsh as a nursery area, and development of salinity tolerances/osmotic regulatory capabilities were evaluated for each, considering these in the context of variability of environmental conditions, especially of salinity. Five different patterns of reproduction are shown by these 11 species, and only A. xenica appears to be limited to reproducing in the salt marsh environment. Some of these species are capable of reproducing throughout the year. Several of the species are annuals, most others live only 2 or 3 years. Eight species (those other than M. cephalus, A. xenica and G. holbrooki) were found to show no size relationship, large juvenile to adult sizes, in osmotic regulatory capabilities.     

Response to drought among farmers and herders in southern Kajiado District,Kenya

From 1972 to 1976 rainfall in Kajiado District of Kenya was below normal. The capacity of the farming and herding systems to cope with the consequent reduction in production is discussed within a context of changing land-use patterns and altered resource availability. It is concluded that land-use planning to allocate the available land and water resources and to promote off-farm employment is required to reduce the vulnerability of the population to future drought conditions.