A 3-Year Adaptation Study of Three Distinct Grapevine Cultivars under Midwestern Field Conditions

Simultaneous responses of American (Concord), European (Pinot Noir), and American-European hybrid (Traminette) cultivars to seasonal and diurnal variation in field environmental conditions were assessed to propose suitable cultivars for potential use for selection and breeding in grapevines in dry areas. ‘Pinot Noir’ had higher gas exchange parameters, higher water potential, and chlorophyll fluorescence, while ‘Concord’ had the lowest values in all three seasons and experienced moderate stress by the end of each season. The dry conditions in 2005 caused water potential to decline sharply compared to values recorded in 2004 and 2006. ‘Pinot Noir’ and ‘Traminette’ exhibited a mild stress, while ‘Concord’ exhibited a moderate stress in 2006. Photosynthetic rate decreased slightly during the summer with a slight recovery at the beginning of September, and did not differ across the seasons among cultivars. Stomatal conductance followed the same pattern. However, in both 2004 and 2005, stomatal conductance dropped sharply late in the season because of frequently occurring high temperatures that were greater than 32 °C. Maximum morning values of Fv/Fm were within the optimal range. The study suggests the presence of marginal photoinhibition during mid-summer in Concord cultivars, because no full recovery of photochemical efficiency early in the evening was observed. The European cultivar (Pinot Noir) and the American-European hybrid (Traminette) are more adapted to field conditions in Kansas than Concord cultivars. However, high cold-mortality of Pinot Noir due to high sensitivity to cold winter temperature makes the hybrid cultivars the most suitable cultivar for Midwest regions with relatively cold winters.     

Bioremediation of petroleum-contaminated soils using Streptomyces sp. Hlh1

Purpose

Bioremediation using microorganisms is a promising strategy to remediate soil with petroleum hydrocarbons. Streptomyces sp. Hlh1, an endophytic strain, has previously demonstrated the ability to degrade crude petroleum in liquid culture. To apply this strain at field scale, it is necessary to test its ability to colonize the soil, compete with native microbiota, and remove the petroleum hydrocarbons under unfavorable conditions. Herein, a study was conducted to evaluate the performance of Streptomyces sp. Hlh1 to remove crude petroleum from contaminated sterilized and non-sterilized soils.

Materials and methods

Soils samples, contaminated with 2%, 5%, and 10% of petroleum, were inoculated with Streptomyces sp. Hlh1, and incubated at 30 °C for 4 weeks. At the end of bioremediation assays, the pollutant concentrations were determined by Gas chromatography flame ionization detector and the degradation rates were also calculated. The survival of the strain in the soil was estimated and the toxicity of metabolites was evaluated on Lactuca sativa.

Results and discussion

Streptomyces sp. Hlh1 was able to grow and remove total petroleum hydrocarbons (TPH), n-alkanes, and aromatic hydrocarbons found in soil samples. In sterilized soil samples, Streptomyces sp. Hlh1 removed up to 40% of TPH at an initial concentration of 10%. Whereas, the maximum TPH removal reached was 55% in non-sterilized soil at an initial concentration of 2%. In addition, it was observed that the degradation of aromatic hydrocarbons was more active than n-alkanes. The strain grew well and produced high biomass in contaminated soil. Lettuce seedling was found to be the adequate bioindicator to assess the toxicity of petroleum end products. Streptomyces sp. Hlh1 performed a successful bioremediation, which was confirmed through the phytotoxicity test.

Conclusions

The study shows the first insight of the contribution of free endophytic actinobacterial strain in the bioremediation of petroleum-contaminated soil; therefore, it suggests that Streptomyces sp. Hl1 can be usefully exploited at field scale.

     

Effect of gamma-irradiation combined with washing and waxing treatment on physicochemical properties,vitamin C,and organoleptic quality of Citrus clementina Hort. Ex. Tanaka

To enhance the shelf life of a late variety of Moroccan Citrus clementina (Nour), ionizing treatments were applied at 0.3 kGy, as well as washing (cold water) and waxing treatments. It has been found that, despite the irradiation treatment, the washing and waxing treatment do not improve the quality of C. clementina, but rather result in yellower peels, peel injury, and reductions of vitamin C content, acidity, and soluble solids. However, gamma-irradiation alone enhanced significantly (p 相似文献