Search Results

You are looking at 1 - 10 of 739 items for :

  • metabolites x
  • All content x
Clear All
Full access

Keletso C. Mohale, Araya T. Hintsa, Machel A. Emanuel, and Fhatuwani N. Mudau

Bush tea ( A. phylicoides DC.) is a South African indigenous and traditional herbal tea rich in secondary metabolites, which have therapeutic effects ( Padayachee, 2011 ), pharmacological properties ( McGaw et al., 2007 ), and different phenolic

Open access

Zhijun Zhang, Huaifeng Liu, Junli Sun, Songlin Yu, Wang He, Tianyuan Li, and Zhao Baolong

concentrations of key chemical constituents. Grape seeds comprise flavonoids and other metabolites that improve plant biotic and abiotic resistance. They also have bactericidal and antiviral effects and potential roles in preventing cardiovascular and

Free access

Dean A. Kopsell, Carl E. Sams, and Robert C. Morrow

secondary metabolite phytochemicals, which provide benefits beyond normal health maintenance and nutrition and play active roles in chronic disease reductions ( Kopsell and Kopsell, 2010 ). Stress is a term used to collectively describe numerous conditions

Free access

Mark G. Lefsrud, Dean A. Kopsell, and Carl E. Sams

LED arrays may facilitate investigation on the impact of specific wavelengths on secondary metabolite production in vegetable crops. Literature Cited Antonious, G.F. Kasperbauer, M.J. Byers, M.E. 1996 Light

Open access

Hong-jia Xu, Masafumi Johkan, Toru Maruo, Natsuko Kagawa, and Satoru Tsukagoshi

chlorophyll fluorescence could partially explain how K and Na affect the physiological response of low-K lettuce. Soluble sugars are the primary metabolites of photosynthesis. They play an important role in osmotic regulation with K and amino acids ( Shabala

Free access

Raquel Enedina Medina-Carrillo, Samuel Salazar-García, Jorge Armando Bonilla-Cárdenas, Juan Antonio Herrera-González, Martha Elva Ibarra-Estrada, and Arturo Álvarez-Bravo

metabolites and lignin in the skin of ‘Hass’ avocado fruit at five developmental stages and from three producing regions. Values of Pr > F. Influence of fruit developmental stage on the concentration of SMs and lignin in the skin. In general, the TPC

Free access

Dean A. Kopsell, Carl E. Sams, T. Casey Barickman, and Robert C. Morrow

intensity) ( Kim et al., 2004 ). Our central hypothesis is that accumulation of primary and secondary metabolites in specialty vegetable crops will be higher under narrow-band LED light where plants only receive blue and red wavelengths as compared with full

Open access

Zhibin Fan, Kai Zhang, Fengyun Wang, Xiaodan Zhao, Ruiqin Bai, and Boling Liu

had a significant cytotoxicity against cultured human tumor cell lines ( Ryu et al., 1996 ). Dried roots of S. miltiorrhiza have been found to contain relatively large amounts of the important secondary metabolites (tanshinones and diterpenoid

Free access

Bruno Defilippi*, Abhaya Dandekar, and Adel Kader

To understand the role of ethylene in overall flavor of apple fruits, ethylene production, and action were reduced using apple trees lines transformed for suppressing activity of ACC-synthase or ACC-oxidase enzymes, and 1-methylcyclopropene (1-MCP), an ethylene action inhibitor. A major reduction in ethylene biosynthesis and respiration rates was measured in fruits from these treatments. As expected, we found differential levels of dependence of flavor components on ethylene biosynthesis and action. Regarding aroma production, an ethyleneassociated event, headspace analysis showed a reduction in ester production in the ethylene-suppressed lines and in the apples treated with 1.0 μL·L-1 1-MCP for 20 hours at 20 °C. However, no major differences were observed in concentrations of alcohol and aldehyde volatiles. Other flavor metabolites that showed an ethylene-dependent pattern were organic acids and sugars. Malic acid degradation was significantly reduced under ethylene suppressed conditions, showing a recovery after exposing the fruit to ethylene. Sucrose and fructose concentrations were influenced by suppression or enhancement of ethylene. Total phenolics and individual phenolics showed an ethylene-dependent behavior only when ethylene biosynthesis was reduced, but not when ethylene action was affected. These results suggest that the regulatory mechanisms of aroma biosynthesis in apple are under partial ethylene regulation. Therefore, we are using the ethylene suppressed apple fruits study the channeling and regulation of other metabolic pathways that lead to the manifestation of a complex trait like fruit quality.

Free access

Joel L. Shuman, Ron Mittler, and Vladimir Shulaev

Drought and heat stress have been extensively studied in plants, but little is known about how the combination of drought and heat impact their physiology and metabolism. The metabolite profile of Arabidopsis subjected to heat, drought, and the combination of heat and drought were analyzed by gas-chromatography-mass spectrometry (GC-MS). Fatty acid retention time standards and the internal standard (IS) ribitol (adonitol) were added to each leaf sample and the polar phase was extracted, methoximated, and derivatized (trimethylsilylated) prior to analysis by GC-MS (Trace DSQ with Combi-PAL autosampler). Compounds were identified based upon retention time (relative to fatty acid standards) and comparison with reference spectra in our custom mass spectral library. Semi-quantitation of compound peak area was done relative to the internal standard. Plants subjected to both heat and drought stress accumulated sucrose and other sugars/sugar alchohols such as maltose, gulose, mannitol. The amino acid proline (Pro) was found in drought-stressed plants, but not found in drought- and heat-stressed plants. Proline has been reported to function as an osmoprotectant in cold-, salt-, and drought-stressed plants, but could be toxic to drought- and heat-stressed plants. We found that growth of heat-stressed Arabidopsis seedlings is inhibited by Pro, but not in drought- and heat-stressed seedlings. These results also indicate that sucrose replaces proline as the major osmoprotectant in heat- and drought-stressed plants. Plants subjected to combined heat and drought also exhibited enhanced respiration, suppressed photosynthesis, and distinct transcriptome expression.