Phenolic acid and flavonoid diversity in four Eucalyptus species
Fazilet Özlem Albayrak | Yüksel Keleş
The economic importance of Eucalyptus trees is due to their rapid growth and high biomass productivity, as well as the beneficial chemical compounds found in their various tissues. Eucalyptus cultivation is common in the southern part of Turkey, especially in the coastal areas of the Mediterranean. In this study, phenolic acids and flavonoids were analyzed in methanol extracts leaf tissues of four eucalyptus species by HPLC. Fifteen different phenolic compounds were determined in the leaf tissues of the four Eucalyptus species examined. The highest total phenolic amounts were found in E. botryoides (160.56 mg g-1DW), followed by E. tereticornis (66.47 mg g⁻¹ DW) and E. citriodora (64.02 mg g⁻¹ DW). Twelve different compounds were determined in E. botryoides and E. citriodora species, 10 in...
Responses of antioxidant defense system of Helianthus annuus to abscisic acid treatment under drought and waterlogging.
Yüksel Keleş, Serpil Ünyayar
The effect of abscisic acid (ABA) treatment on growth pigments and antioxidant defense system were in vestigated in seedlings of Helianthus annuus (cvs. Nantio F1 and Özde mirbey) subjected to drought and waterlogging stress. In addition, seedlings were sprayed with 10 µM ABA three times every other day. Reltive growth rate (RGR) was significantly reduced in both genotypes under drought stress, however, this growth inhibition was less in ABA-treated plants. Total chlorophyll content increased by drought stress in both gentypes. Ascorbate was not influenced by drought, while α-tocopherol in creased in cv. Nantio F1. Ascorbate and α-tocopherol in creased with drought stress in cv. Özdemirbey. ABA treat ment de creased ascorbate and ß-carotene contents while it increased α-tocopherol and xan...
Antioxidant Capacity and Protein contents of Five Marine Microalgae
Yaman Halil | Eker-Develi Elif | Keles Yuksel
Antioxidant capacity, chlorophyll, marker pigment, and protein contents of four diatoms (Helicotheca tamesis, Haslea silbo, Nitzschia navis-varingica, and Asterionellopsis glacialis) and one cyanobacterium (Spirulina subsalsa) have been investigated. N. navis-varingica exhibited the highest chlorophyll a, fucoxanthin, ascorbic acid, and total antioxidant capacity (TAC) among the five species studied. Cupric-reducing antioxidant capacities of N. navis-varingica and H. silbo were higher than other species studied. A. glacialis exhibited the highest total superoxide dismutase (SOD) activity, H. silbo displayed the highest ascorbate peroxidase (APX) activity, and Spirulina subsalsa had the maximum phenolic and protein contents. Overall, compared to other studies in the literature, the...
Aqueous extract of Acacia cyanophylla leaves as environmentally friendly inhibitor for mild steel corrosion in 1 MH2SO4 solution
Gülşen Avcı, Yüksel Keleş
The efficiency of Acacia cyanophylla leaves extract as an environmentally friendly inhibitor for mild steel in aerated aqueous 1M H2SO4 solution has been investigated by potentiodynamic polarization measurements and electrochemical impedance spectroscopy techniques. Addition of inhibitor decreases the corrosion current whereas the corrosion potential values show slight shifts in positive directions. Inhibition efficiency was found to be about 93% (the maximum value was determined from the polarization curve). Efficiencies obtained from both electrochemical techniques are in good agreement. Adsorption of acacia cyanophylla leaves extracton mild steel surface in 1 M H2SO4 solution obeys Langmuir adsorption isotherm. Polarization curves were also obtained at different temperatures in order to...
The role of biochemical regulation on the adaptation of gypsophile and gypsovag species
Fazilet Özlem Çekiç, Yüksel Keleş
There are two groups of plant species that spread in gypsiferous soils. While gypsophytes only grow on gypsi ferous soils, gypsovags can grow on both gypsum and non-gypsum soil. Adaptation of plants to gypsum soils requires biochemical arrangements in addition to proper morphological and physiological characteristics. In this study, three gypsophyte species and on-gypsum and non-gypsum speciments of three gypsovag species were examined for antioxidant capacities. The average phenolic substance contents were 126.5, 30.5 and 37.6 μgg−1 DW in gypsophile, on-gypsum and in non-gypsum gypsovag species respectively. Gypsophyte, Thymus leucos tomus var. gypsaceus species was identified as having seven different phenolic compounds and the highest phenolic substance content. However, phenolic subst...
Relationship between boron content and antioxidant compounds in Citrus leaves taken from fields with different water source
Keleş, Yüksel
Boron contamination in the agricultural lands is an important problem for Western Turkey, which has rich boron deposits. This study was carried out in Nazilli regions upon orange (Citrus sinensis L. Osbeck) plants irrigated with relatively high boron laden channel waters (LCI) and with well waters (LWI) which contain lower amounts of boron. The leaves of the plants irrigated with channel water were found to contain twice the amount of boron compared with those irrigated with well waters. Boron content of leaves in both groups were approximately ten times the boron content in the soil on which they are grown. In the leaves of the plants irrigated with channel waters there were approximately 50% chlorophyll loss and higher chlorophyll a/b and caretonoid/chlorophyll ratios. In the excessive b...
Gall wasps change the biochemical composition of Eucalyptus leaves
Yüksel KELEŞ
Determining the effects of gall wasps on leaf biochemistry may contribute to the understanding of damage mechanisms. The study was carried out in eucalyptus plantations in the coastal regions of the Northeastern Mediterranean (Tarsus/Mersin/Turkey). Biochemical analyses were performed on Eucalyptus camaldulensis leaves infested and uninfested with two different gall wasps (Leptocybe invasa and Ophelimus maskelli) and the data were compared. The flavonoid content of the leaves reduced 16.5% in leaves infested with L. invasa and 33.7% with O. maskelli. Total antioxidant capacity decreased with O. maskelli infestation but did not change with L. invasa infestation. Copper ion reduction capacity increased significantly with both pest infestations. Ascorbic acid increased by 87% in L. invasa i...
Role of antioxidant defense system and biochemical adaptation on stress tolerance of high mountain and steppe plants
Keleş, Yüksel
Eleven species were collected from Northwest Anatolian mountains (1500–2000 m) and 18 species were collected from the Central Anatolian steppes (850–1000 m) in June 1998 and 1999. In all the species investigated, the water and dry matter percentages and solute contents were measured. The chlorophyll, b-carotene, ascorbate and a-tocopherol contents and catalase (CAT), superoxide dismutase (SOD) andglutathione reductase (GR)enzymeactivities oftheplants werealsodetermined.Thesteppeplantshadlowerwatercontentcomparedwith alpine plants. The chlorophyll contents of the plants investigated did not change with altitude. However, the carotenoid/chlorophyll ratio of alpine plants was found to be significantly higher. The antioxidant/chlorophyll ratio of the trees and shrubs was higher than that of he...