In this study was carried out to determine the effects of humic acid in heavy metal stress of lettuce changes in some of the morphological and physiological characteristics. In studies conducted in controlled greenhouse conditions, lettuce plants subjected to four different 4 different humic acid levels humic acid doses (0, 2, 4, 8 L/da) and 4 different heavy metal irrigation levels (Control: 0 ppm; I. mixture: 0.2 ppm Cu + 0.01 ppm Cd + 5 ppm Pb + 2 ppm Zn; II. mixture: : 0.4 ppm Cu + 0.02 ppm Cd + 10 ppm Pb + 4 ppm Zn; III. mixture: 0.8 ppm Cu + 0.04 ppm Cd + 20 ppm Pb + 8 ppm Zn). Four weeks after at heavy metal and humic acid treatment young plants were harvested and the shoot fresh and dry weight, root fresh and dry weight, shoot and root length, and leaf areas, MDA, superoxyde dismutase (SOD) and glutathione reductase (GR) were determined. The most highly toxic effects were determinate III. mixture level (0.8 ppm Cu + 0.04 ppm Cd + 20 ppm Pb + 8 ppm Zn). MDA and antioxidative enzyme activities increased in plants irrigated with water containing a mixture of heavy metal. Humic acid applications had a positive effect on reducing of the limiting effect of heavy metal stress on growth and development.

Events such as oxidative stress caused by spinal cord injury (SCI) are a serious condition because they negatively affect many organs. Alternative treatment options for this type of injury are quite limited. In this study, we planned to investigate the effect of oxidative damage on the spleen tissue of rats with spinal cord damage and the protective role of valproic acid (VPA) in this damage. Sixteen Wistar albino rats were divided into two equal groups. No treatment was administered to the rats in Group 1 (SCI-(Control), but a single dose of 300 mg/kg intraperitoneally VPA was administered to the rats in Group 2 (SCI-VPA). Superoxide dismutase (SOD) activities, total antioxidant status (TAS) and total oxidant status (TOS) levels were examined as markers of oxidative stress in spleen tissues taken after decapitation of rats. VPA treatment increased the SOD and TAS level but decreased the TOS level, indicating improved oxidative damage and impaired enzymatic antioxidant levels in spleen tissue homogenate damaged by SCI. We have observed that VPA, which has many beneficial properties, has a significant healing effect on spleen tissue affected by SCI-induced oxidative stress.

Drought stress is one of the most serious abiotic stresses that cause a reduction in plant growth, development and yield in the world. The aim of this study is to reveal the morphological, physiological and biochemical responses of the Demre pepper variety and nine different pepper genotypes against drought stress. Pepper seeds were planted into trays containing peat: perlite (2: 1) mixture. Then, seedlings having two leaves were transferred to plastic pots containing mixture of peat:perlite (2:1) mixture. Drought stress application was started when the plants have four leaves. The control plants were irrigated with nutrition solution. Genotypes were classified according to the severity of leaf damage symptoms by using 0-5 scale. In addition, shoot fresh and dry weight, plant height, stem diameter, leaf number, leaf area, relative water content (RWC), membrane injury index (MII), potassium (K) and calcium (Ca) concentration of shoot, malondialdehyde content (MDA), total chlorophyll and carotenoid, total flavonoid and phenolic content, anitoxidative enzyme activities (superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), ascorbate peroxidase (APX)) were also determined. As a result of the study, it was determined that drought had negative effect in terms of morphological and physiological parameters, and this effect revealed differences among genotypes. While drought stress increased MDA and antioxidative enzyme activity, BIB-6 and BIB-8 genotypes were found to be the most tolerant genotypes among the genotypes examined.

Günümüzde kullanılan birçok terapötik ilaç kaynağını şifalı bitkilere borçludur. Her bitkinin kendine özgü aktivitesi ve biyokimyasal profili vardır. Bu çalışmada günlük hayatta oldukça iyi bilinen üç farklı bitki türü; Helianthus tuberosus, Zingiber officinale ve Raphanus sativus var. niger kullanıldı. İlk defa yapılan bu çalışmada antioksidan aktivite tayini sınırlı olan üç farklı bitki seçilmiş ve aktioksidan kapasiteleri karşılaştırılmıştır. H. tuberosus, Z. officinale ve R. sativus var. niger bitkilerinin gövde kısımları %1.15 potasyum klor ile homojenize edilerek ekstraklar hazırlandı. Daha sonra antioksidan enzim aktiviteleri katalaz (CAT) ve süperoksit dismutaz (SOD) ile oksidatif stres belirteci olan malondialdehit (MDA) düzeyleri spektrofotometrik yöntemlerle saptandı. Araştırma sonucunda en yüksek SOD enzim aktivitesi R. sativus var. niger bitkisinde görülürken, en yüksek CAT enzim aktivitesi ise Z. officinale bitkisinde gözlendi. Öte yandan yer elması bitki ekstraktında MDA düzeyi en yüksek iken, en düşük MDA düzeyi ise Z. officinale bitkisinde gözlenmiştir.