University of Hohenheim

About: University of Hohenheim is a education organization based out in Stuttgart, Germany. It is known for research contribution in the topics: Population & Soil water. The organization has 8585 authors who have published 16406 publications receiving 567377 citations.

Overwintering problems of newly established Miscanthus plantations can be overcome by identifying genotypes with improved rhizome cold tolerance

Abstract: Miscanthus, a perennial rhizomatous C 4 grass, is a potential biomass crop in Europe, mainly because of its high yield potential and low demand for inputs. However, until recently only a single clone, M. × giganteus, was available for the extensive field trials performed across Europe and this showed poor overwintering in the first year after planting at some locations in Northern Europe. Therefore, field trials with five Miscanthus genotypes, including two acquisitions of Miscanthus x giganteus, one of M. sacchariflorus and two hybrids of M. sinensis were planted in early summer 1997 at four sites, in Sweden, Denmark, England and Germany. The field trials showed that better overwintering of newly established plants at a site was not apparently connected with size or early senescence. An artificial freezing test with rhizomes removed from the field in January 1998 showed that the lethal temperature at which 50% were killed (LT 50 ) for M. xgiganteus and M. sacchariflorus genotypes was -3.4°C. However, LT 50 in one of the M. sinensis hybrid genotypes tested was -6.5°C and this genotype had the highest survival rates in the field in Sweden and Denmark. Although the carbohydrate content of rhizomes, osmotic potential of cell sap and mineral composition were not found to explain differences in frost tolerance adequately, moisture contents correlated with frost hardiness (LT 50 ) in most cases. The results obtained form a basis for identifying suitable Miscanthus genotypes for biomass production in the differing climatic regions of Europe.

Carotenoid Esters in Vegetables and Fruits: A Screening with Emphasis on β-Cryptoxanthin Esters

Abstract: Carotenoids are found in food plants in free form or as fatty acid esters. Most studies have been carried out after saponification procedures, so the resulting data do not represent the native carotenoid composition of plant tissues. Therefore, nonsaponified extracts of 64 fruits and vegetables have been screened to determine the amount of carotenoid esters in food plants. Because one of the major problems in the quantitation of carotenoids is the availability of pure standard material, the total carotenoid ester content was calculated as lutein dimyristate equivalents. Lutein dimyristate was independently synthesized from lutein and myristoyl chloride. The highest ester concentrations were found in red chili (17.1 mg/100 g) and orange pepper (9.2 mg/100 g); most of the investigated fruits and vegetables showed concentrations up to 1.5 mg/100 g. Special attention was dedicated to beta-cryptoxanthin esters. To enable an accurate detection of the beta-cryptoxanthin ester content, beta-cryptoxanthin was purified from papaya and used for synthesis of beta-cryptoxanthin laurate, myristate, and palmitate, representing the major beta-cryptoxanthin esters in food plants. The study proved tropical and subtropical fruits to be an additional source of beta-cryptoxanthin esters in the human diet. The contents ranged from 8 microg/100 g beta-cryptoxanthin laurate in Tunisian orange to 892 microg/100 g beta-cryptoxanthin laurate in papaya.