Reduced Germination and Seedling Vigor of Weeds with Root Extracts of Maize and Soybean,and the Mechanism Defined as Allelopathic

Journal of Crop Science and Biotechnology - Due to the negative consequences of synthetic herbicides use and their reducing effectiveness due to development of resistant weeds, promotion of...     

黄瓜新品种‘粤丰’

 ‘粤丰’是由早熟抗病的‘豫优4号’为母本，与‘渝亮3号’杂交育成的华北型黄瓜一代杂种。生长势强，主侧蔓结瓜，雌花节率高，回头瓜多。瓜条顺直、美观，长棒形，瓜长38.0 cm，横径3.8 cm，肉厚1.2 cm，单瓜质量约390 g，皮色深绿，光泽度好，刺白，瘤小而密，肉质脆，味微甜，商品性好，耐热，抗病、抗逆性强。适合华南地区春秋季种植。     

Relationships between soil and vegetation characteristics of tundra ecosystems and their use to assess soil resilience, degradation, and rehabilitation potentials

Definitions of the notions of soil resilience and degradation of the soil-vegetation cover are suggested. These problems are considered with respect to vulnerable tundra ecosystems. The analysis of available experimental data made it possible to obtain empirical equations characterizing the relationships between the plant productivity and the soil properties. These equations can be used to predict the degree of soil degradation under particular types of technogenic loads and the soil and vegetation potential for the natural restoration or artificial rehabilitation of the soil-vegetation cover in tundra ecosystems. The results obtained can be applied for the development of optimal nature management strategies in the areas of oil and gas fields in the north.     

Immunohistochemical detection of scrapie prion proteins in clinically normal sheep in Pennsylvania.

Following diagnosis of scrapie in a clinically suspect Suffolk sheep, 7 clinically normal flockmates were purchased by the Pennsylvania Department of Agriculture to determine their scrapie status using an immunohistochemical procedure. Two of the 7 euthanized healthy sheep had positive immunohistochemical staining of the prion protein of scrapie (PrP-Sc) in their brains, nictitating membranes, and tonsils. The PrP-Sc was localized in the areas of the brain where, histopathologically, there was neurodegeneration and astrocytosis. The PrP-Sc occurred within germinal centers of the affected nictitating membranes and tonsils and was located in the cytoplasm of the dendrite-like cells, lymphoid cells, and macrophages. These results confirm that immunohistochemical examination of the nictitating membrane can be used as a screen for the presence of scrapie infection in clinically normal sheep at a capable veterinary diagnostic laboratory. In sheep with a PrP-Sc-positive nictitating membrane, the diagnosis of scrapie should be confirmed by histopathology and immunohistochemical examination of the brain following necropsy. Following full validation, immunohistochemistry assays for detection of PrP-Sc in nictitating membrane lymphoid tissues can improve the effectiveness of the scrapie control and eradication program by allowing diagnosis of the disease in sheep before the appearance of clinical signs.     

Injection and sampling methods for drug residue study in calf muscle

Eight calves, weighing 50-150 kg, were given intramuscularly 5 ml of ampicillin (ABPC) aqueous suspensions (200 mg potency/ml) in their right and left gluteal and femoral regions. All calves were sacrificed one hour later to confirm the location of injected drug. The drug was found in a muscle layer when injected with a needle 15 mm long to the following positions, 1. the midpoint between the central position of the gluteal region (CG) and the tuber coxae (M-CTc), 2. the midpoint between CG and the tuber ossis ischii (M-CTo), 3. the central position of M. semimembranaceus in the femoral region (CF). Seven calves, weighing 130-150 kg, were given intramuscularly 5 ml of ABPC suspensions at M-CTo and CF and sacrificed one hour (4 calves) and 3 days (3 calves) later. ABPC diffused along the long axis of the muscle fibers but not to the radial direction. ABPC was detected only in the injected muscle layer even after 3 days indicating that the drug did not diffuse to the neighboring muscles. In the injected muscle layer, concentration of ABPC was remarkably different from part to part. From these results, sampling of the injected muscle for the drug residue study was proposed as follows: 1. isolate about 100 g of muscle just under the stick point marked on the skin considering the direction of drug diffusion, and 2. isolate separately about 200 g of the surrounding muscle to confirm if the sampling is appropriate.     

Diurnal and seasonal occurrence,feeding habits and mating behavior ofMaladera matrida adults in Israel

Adult populations ofMaladera matrida Argaman (Coleoptera: Scarabaeidae), a beetle highly injurious to agricultural crops, were studied in the coastal plain of Israel from 1985 to 1988. There were two generations annually. Adults emerged in March, April or May and disappeared in October or November. The beetles are on the wing, mate, and feed at twilight and in the dark. Feeding and mating behavior, sex ratio, and preferred food plants were studied.     

Monellia costalis (Fitch), a new host forZoophthora radicans (Brefeld) Batko andEntomophthora Planchoniana Cornu (Zygomycetes: Entomophthoraceae) in Israel

Two entomophthoraceous species,Zoophthora radicans andEntomophthora planchoniana, were found on the yellow pecan aphid,Monellia costalis, shortly after it was introduced into Israel. This aphid is a new host forZ. radicans anywhere. The fungus was isolated in pure culture and artificially inoculated on three Dipteran species:Musca domestica, Drosophila melanogaster andCeratitis capitata, as well as on the HemipteranEmpoasca sp. from pecan. The identity ofZ. radicans and some new characters,e.g. the production of two kinds of rhizoids, are discussed. The possibility of usingM. domestica as a vector for artificial spread of the fungus, as a means of biological control of various insect pests, is advocated.