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Tomato plants were cultivated (from 2 to 23 days after germination) in media with NO3-, NH+, or a mixture of both forms in different proportions used as the N source given with or without 5 mol dm-3 HCO3-. The accumulation of soluble sugars (reductng sugars and sucrose) and free amino acids was higher in the roots and leaves of NH+-fed plants than in NO3--fed plants. Starch accumulation in NH4+-fed plants was higher in leaves (about 28 %) and lower in roots (about 37 %) in comparison with that of NO3-- fed plants. Plants cultivated in media containing a mixture of NO3-/NH4+ were characterized by a lower content of sugars and amino acids accumulation in comparison with that in plants fed with NO3- or NH4+. An elevated HCO3- concentration in the rhizosphere stimulated the accumulation of soluble sugars and free amino acids in all the experimental variants. There were only small differences in the starch content.
Proteolysis and lipid oxidation in the vacuum-packed leg and breast muscles from Mullard drakes stored at 1°C were studied. As proteolysis indicators there were determined proteolytic activity, contents of amino nitrogen and free amino acids (FAA), and TBARS values as indicators of oxidative changes. Changes were also determined in the proteolytic activity, TBARS values and contents of: amino nitrogen and FAA. As a result, 18 FAA were found in breast muscles and 19 in leg and their total contents after 1 day of storage were 184.39 mg/100 g tissue, and 233.33 mg/100 g tissue (respectively). In the case of breast muscles a significant increase in the content of detected FAA (except Pro) was noted after 13 days of storage and in the leg muscles (except Asp) after 5 days of storage. It was established that the proteolytic activity decreased (ca. 38%) in breast after 18 days and in leg (ca. 30%) after 5 days of storage. The content of amino nitrogen significantly increased in breast muscles after 18 days and in leg muscles after 5 days of storage. During storage, TBARS values were observed to increase continuously in breast muscles, whereas in legs they first increased after 5 days and then were observed to decrease.
Host specialization plays a central role in physiological diversification of aphids and plant-insect co-evolution. Different morphs of the bird cherry-oat aphid (Rhopalosiphum padi L.) are specialized and locally adapted to both primary and secondary hosts. The abundance of bird cherry-oat aphid population was estimated using the technique of direct counting of aphid individuals infesting 50 randomly selected, fully expanded 1-year side shoots of bird cherry (approx. 40 cm long) grown in the Municipal Park „Aleksanria” in Siedlce (central-eastern Poland). Entomological observations were conducted during three consecutive vegetation seasons: 2001–2003. The impact of R. padi feeding on composition of free amino acids within leaves of its primary host (the bird cherry, Prunus padus L.), infested and uninfested by aphids were studied. Eight essential amino acids (Val, Thr, Phe, Ileu, Leu, Met, His and Lys) and seven non-essential amino acids (Asp, Glu, Pro, Ser, Ala, Gly and Tyr) were identified in the bird cherry-oat leaves with the use of highperformance liquid chromatography (HPLC) separation. There were quantitative differences in free amino acids content between the tested bird cherry-oat leaves (infested and uninfested by aphids). Levels of the free amino acids were decreased in leaves attacked by R. padi, and detailed analyses revealed about 20% decline in the content of studied components during maximal aphid abundance in comparison with non-infested leaves. Additionally, the feeding behavior of the bird cherry-oat aphid seasonal morphs (fundatrix, fundatrigeniae, alatae) on the primary host was investigated. Using the electrical penetration graph (EPG) we showed differences in feeding behavior of bird cherry-oat aphid morphs on primary host. The total probing time was greatest for fundatrigeniae among all studied morphs. These individuals spent more time during phloem sap ingestion then others. Adults of alatae were not active in the phloem sap ingestion on the bird cherry. Among the tested morphs xylem sap ingestion activity was greatest for alatae. It is hypothesized that rejection of primary host and subsequent the bird cherry-oat aphid migration onto secondary hosts may be stimulated by the decline in levels of free amino acids within primary host leaves caused by long-term R. padi feeding. Comparative analyses of the aphid probing behavior additionally proved that P. padus leaves possessed high nutritive value of food for non-winged morphs (early stages of aphid infestation), while not sufficient for winged alatae (terminal phase of infestation).
Qualitative and quantitative contents of free amino acids in the flag leaves and ears of winter tritica- le treated with herbicide Chwastox D 179 SL were determined, using ion-exchange chromatography. Fifteen protein amino acids were identified and determined. The obtained results showed that her­bicide treatment did not influence the qualitative composition of free amino acids in the tested win­ter triticale. The quantitative analysis proved a decrease of the studied compounds in plants treated with Chwastox D 179SL.
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