Phenological and physiological evaluation of first and second cropping periods of sorghum and maize crops

Environmental conditions influence phenology and physiological processes of plants. It is common for maize and sorghum to be sown at two different periods: the first cropping (spring/summer) and the second cropping (autumn/winter). The phenological cycle of these crops varies greatly according to the planting season, and it is necessary to characterize the growth and development to facilitate the selection of the species best adapted to the environment. The aim of this study was to characterize phenological phases and physiological parameters in sorghum and maize plants as a function of environmental conditions from the first cropping and second cropping periods. Two parallel experiments were conducted with both crops. The phenological characterization was based on growth analyses (plant height, leaf area and photoassimilate partitioning) and gas exchange evaluations (net assimilation rate, stomatal conductance, transpiration and water-use efficiency). It was found that the vegetative stage (VS) for sorghum and maize plants was 7 and 21 days, respectively, longer when cultivated during the second cropping. In the first cropping, the plants were taller than in the second cropping, regardless of the crop. The stomatal conductance of sorghum plants fluctuated in the second cropping during the development period, while maize plants showed decreasing linear behaviour. Water-use efficiency in sorghum plants was higher during the second cropping compared with the first cropping. In maize plants, in the second cropping, the water-use efficiency showed a slight variation in relation to the first cropping. It was concluded that the environmental conditions as degree-days, temperature, photoperiod and pluvial precipitation influence the phenology and physiology of both crops during the first and the second cropping periods, specifically cycle duration, plant height, leaf area, net assimilation rate, stomatal conductance and water-use efficiency, indicating that both crops respond differentially to environmental changes during the growing season.     

Net depth response of a depth-controllable (towed) gillnet for fish sampling

SUMMARY: Flume-tank experiments were performed to examine the depth response of a new type of depth-controlled gillnet. Variations of net depth were investigated as the warp was paid out and wound up for different changes of warp length, main sinker weights, and winch speeds. In most experiments, when the warp finished paying out, the net continued to descend and then ascended slightly to an equilibrium depth (overshoot phenomenon). The overshoot distance was nearly constant when the warp was wound up and increased linearly with increasing winch speed when the warp was paid out. An increase in winch speed reduced net settling time, which converged on a constant value for both paying out and winding up.     

Anti-erythrocyte membrane antibodies detected in sera of dogs naturally infected with Babesia gibsoni.

Due to the potential for anti-erythrocyte membrane antibodies as possible enhancers of erythrocyte destruction, the presence of serum anti-erythrocyte membrane antibodies in 31 dogs with Babesia gibsoni infection admitted to a veterinary hospital was investigated by an enzyme linked immunosorbent assay (ELISA) and immunoblotting analyses. This infection resulted in an increase of anti-erythrocyte membrane antibodies in 84% (IgG) and 74% (IgM) of 31 infected dogs, respectively. This was confirmed by the similarity in the protein profiles of the erythrocyte membrane antigens immunoblotted with rabbit antiserum to dog erythrocyte membrane antigens and infected dog serum. These results suggest the production of anti-erythrocyte membrane antibodies was induced by B. gibsoni infection.     

Wetland effects on lake water quality in the Minneapolis/St. Paul metropolitan area

A method developed to evaluate the cumulative effect of wetland mosaics on water quality was applied to 33 lake watersheds in the seven-county region surrounding Minneapolis-St. Paul, Minnesota. A geographic information system (GIS) was used to record and measure landscape variables derived from aerial photos. Twenty-seven watershed land-use and land-cover variables were reduced to eight principal components which described 85% of the variance among watersheds. Relationships between lake water quality variables and the first six principal components plus an index of lake mixis were analyzed through stepwise multiple regression analysis. A combination of three landscape components (wetland/watershed area, agriculture/wetlands, and forest/soils components) explained 49% of the variance in a trophic state index, even though most of the lakes examined were already highly eutrophic, and thus were influenced by internal loading. The regression equations explained a range of 14 to 76% of the variation in individual water quality variables. Forested land-use was associated with lower lake trophic state, chloride, and lead. High lake trophic state was associated with agricultural land-use and with wetland distance from the lake of interest. The extent of wetlands was associated with low total lead and high color in lakes downstream. Wet meadows or herbaceous, seasonally-flooded wetlands contributed more to lake water color than did cattail marshes.     

Detection of antibody against transmissible gastroenteritis virus of pigs by indirect immunoperoxidase antibody test

Immunoperoxidase intibody (IPA) test was developed for detecting antibody against transmissible gastroenteritis (TGE) virus of pigs. The IPA antibody titers in sera collected in the field from 82 pigs were approximately seven times higher than those obtained in a serum-neutralization test. The correlation between the TGE antibody concentrations in the IPA and serum neutralization tests was positive (r = +0.74). The IPA tests appears to have the potential for routine laboratory use for serologic diagnosis of TGE.     

Catalog of Micro-Tom tomato responses to common fungal, bacterial, and viral pathogens

Lycopersicon esculentum cultivar Micro-Tom is a miniature tomato with many advantages for studies of the molecular biology and physiology of plants. To evaluate the suitability of Micro-Tom as a host plant for the study of pathogenesis, Micro-Tom plants were inoculated with 16 well-known fungal, bacterial, and viral pathogens of tomato. Athelia rolfsii, Botryotinia fuckeliana, Oidium sp., Phytophthora infestans, and Sclerotinia sclerotiorum caused typical symptoms and sporulated abundantly on Micro-Tom. Micro-Tom was resistant to Alternaria alternata, Corynespora cassiicola, and Fusarium oxysporum. When Micro-Tom was inoculated with 17 isolates of Ralstonia solanacearum, many isolates induced wilt symptoms. Agrobacterium tumefaciens also was pathogenic, causing crown galls on stem tissue after needle prick inoculation. In Micro-Tom sprayed with Pseudomonas syringae pv. tomato, P. s. pv. tabaci, or P. s. pv. glycinea, bacterial populations did not increase, and yellow lesions appeared only on leaves sprayed with P. s. pv. tomato. Tomato mosaic virus, Tomato aspermy virus, and Cucumber mosaic virus systemically infected Micro-Tom, which developed symptoms characteristic of other cultivars of tomato after infection with the respective virus. These results indicated that Micro-Tom was generally susceptible to most of the important tomato pathogens and developed typical symptoms, whereas certain pathogens were restricted by either hypersensitive resistance or nonhost resistance on Micro-Tom. Therefore, an assortment of Micro-Tom–pathogen systems should provide excellent models for studying the mechanism of susceptible and resistant interactions between plants and pathogens.     

Induction of oestrus by administering Inhibin antiserum along with equine chorionic gonadotropin in anoestrous bitches

As dogs experience oestrus only once or twice a year, it is necessary to establish an effective method of oestrous induction for efficient breeding. In the present study, we evaluated inhibin antiserum (IAS) on oestrous induction in anoestrous females. Bitches were administered 0.5 ml/kg IAS or a mixture of 50 IU/kg equine chorionic gonadotropin (eCG) and 0.5 ml/kg IAS and 500 IU human chorionic gonadotropin (hCG) administered 7 days after the mixture injection. As a control, bitches received 50 IU/kg eCG, with 500 IU hCG administered 7 days after eCG injection. Blood-tinged vaginal discharge, vulvar swelling, plasma progesterone concentrations and ovarian follicular development were assessed from day 0 to day 14. IAS alone injection did not induce oestrus in bitches at the anoestrous stage. Conversely, vulvar swelling, blood-tinged vaginal discharge and an estimated luteinizing hormone (LH) surge appeared on days 3–7, days 3–6 and days 7–9 after the IAS+eCG mixture injection, respectively, in all five bitches at the anoestrous stage. The average number of developing and ovulated follicles in bitches administered IAS+eCG was 8.8 and 9.6 respectively. A single eCG injection followed by hCG induced oestrous signs, with an average of 8.3 developing follicles and 4.5 ovulated follicles. This study revealed that IAS alone did not induce oestrus, but when IAS was used in combination with eCG, it induced oestrus and promoted a considerable number of ovulations in anoestrous dogs.     

Polymorphism in promoter region of growth hormone receptor is associated with potential production capacity of insulin‐like growth factor‐1 in pre‐pubertal Holstein heifers

Insulin‐like growth factor‐1 (IGF‐1) is one of the important factors for growth, milk production and reproductive functions and mainly released from the liver in response to growth hormone (GH) via GH receptor (GHR) in cattle. Recently, some single nucleotide polymorphisms (SNPs) were identified in the bovine GHR gene. Some GHR‐SNPs were shown to be related to plasma IGF‐1 concentration in cattle. Hence, the capacity to IGF‐1 production in the liver might be affected by GHR‐SNP and associated with performance in the future. This study examined whether GHR‐SNP is associated with IGF‐1 production in the liver of pre‐pubertal heifers. In 71 Holstein calves, blood samples for genomic DNA extraction were obtained immediately after birth. To genotype the GHR‐SNPs in the promoter region, polymerase chain reaction (PCR) products were digested with restriction enzyme NsiI (cutting sites: AA, AG and GG). All heifers at 4 months of age were intramuscularly injected with 0.4 mg oestradiol benzoate. Blood samples were obtained from the jugular vein just before (0 h) and 24 h after injection. The number of AA, AG and GG at the NsiI site was 0, 17 and 54 respectively. In AG and GG, plasma GH concentrations were higher pre‐injection than 24 h post‐injection (p < 0.01). Moreover, plasma GH concentrations in AG post‐injection were higher than in GG (p < 0.05). In contrast, the GG genotype exhibited higher plasma IGF‐1 concentrations in pre‐injection than post‐injection (p < 0.01), although oestradiol did not change IGF‐1 concentration in the AG genotype. We conclude that the GG polymorphism in the promoter region of GHR is associated with a higher potential capacity of IGF‐1 production in the liver of cattle.