The effects of mycorrhiza, Thiobacillus and Nitroxin (Azotobacter and Azospirillum sp.) biofertilizers under drought stress conditions with four levels of field capacity (FC) (control(100%), 85%, 70%, and 50%) on the antioxidant enzyme activities of medicinal pumpkin (Cucurbita pepo convar. pepo var. Styriaca) were evaluated during the years 2018–2019. Irrigation levels exhibited significant effects on all studied variables, except for the catalase (CAT) enzyme. A significant correlation was observed between the effects of irrigation levels and biofertilizers on antioxidant enzymes, soluble protein content, and grain yield. The highest activity of catalase and ascorbate peroxidase (APX) enzymes was achieved using mycorrhiza in 50% FC. Increasing drought intensity and mycorrhiza stimulated glutathione reductase (GR) and guaiacol peroxidase (GPX) activities by 32% and 66%, while Nitroxin increased them by 16% and 43%, respectively. Under severe drought stress conditions, only mycorrhiza exhibited a positive effect on GR and GPX enzymes. Under moderate and severe drought stress conditions, Nitroxin increased grain yield by 13% and 12.6%, respectively. The irrigation regimes and bio-fertilizers had a significant effect on β-sitosterol percentage. The highest amount was observed at the highest level of drought stress. Among the various bio-fertilizers treatments, the application of Thiobacillus yielded the highest percentage of β-sitosterol. The results of the present study demonstrate that the application of biofertilizers is beneficial in coping with drought stress.

This study investigated the effect of organic fertilizers on vegetative growth and the physiological and antioxidant activity characteristics of thyme plants grown under stress. A factorial experiment was conducted according to randomized complete block design with 12 combinations and 3 replications in the 2018 growing season. The experiment factors were the implementation of organic fertilizers at 4 levels (vermicompost, manure compost, animal manure, and control) and irrigation regime at 3 levels (Irr1, Irr2, and Irr3, respectively, irrigation after 60, 90, and 120 mm evaporation from A pan). The results showed that With delayed irrigation, the chlorophyll a and b contents, total chlorophyll, and carotenoid decreased, while the application of low water stress enhanced the amount of oil and the oil yield with the respective highest values of 2.61% and 3.68 g/m under mild stress conditions. Nonetheless, higher values for the aforementioned properties were noted with the application of vermicompost. Water deficit decreased nutrient uptake (K, P, and N) and relative water content, biological yield, and seed yield of thyme, indicating that thyme was sensitive to drought, and organic fertilizers application improved nutrient uptake (K, P, and N) and relative water content, biological yield and seed yield of the plant within irrigation levels. The activities of catalase, superoxide dismutase and ascorbate peroxidase were reduced under organic fertilizers such as vermicompost and manure compost as compared with control under drought stress. The plants of thyme showed a good response to organic fertilizers under water deficit circumstances, with vermicompost being the most effective.

Cadmium is a widely distributed heavy metal in agricultural soils that affects plant growth and productivity. In this context, the current study investigated the effects of different cadmium (Cd) doses (0, 25, 50, 75, and 100 mg L⁻¹ of CdSO₄) on the growth and physiological attributes of safflower (Carthamus tinctorius L.) including plant height (cm), root length (cm), fresh weight (g) of root, stem, and leaves, leaf number, macro and micro-nutrients, Se, and heavy metal (Cd, Cr, and Pb) content. The experiment was carried out in a completely randomized design (CRD) with four replicates. The results showed that Cd stress significantly negatively affected all growth indices, macro- and micro-nutrients, and heavy metal content. In addition, it increased the MDA and APX activities. The highest amounts of Fe, Mn, Ni, Pb, Zn, K, Na, Cd, Cr, and Cu were determined in plant roots, while the highest values of Ca and Mg were detected in plant stem tissues. High Cd doses decreased the content of Ca, K, Mg, Cr, Cu, Fe, Mn, Ni, Pb, Se, and Zn in safflower plant tissues by 45.47%, 39.33%, 79.28%, 68.21%, 37.06%, 66.67%, 45.62%, 50.38%, 54.37%, 33.33% and 65.87%, respectively, as compared to the control treatments.

In order to meet the demand for medicinal sage (Salvia officinalis L.), which is an important economic product, harvesting from nature has economic value. However, it may not always be of the desired standard and quality. Also, the harvesting from nature endangers their natural population causing their genetic base to decline. For this reason, it is important to produce it in an agrosystem and to increase yield in a sustainable way. In this study, the effects of eleven endophyte bacteria (EB) isolates applications on the development, morphology, and physicochemical properties of Salvia officinalis L. were investigated by climate chamber experiments. Peat+perlite+soil (1:1:2) mixture was used as the growing medium and EB was applied two times by soaking method. Effects of EB applications on shoot/root length, root/stem fresh and dry weight, Dualex values (Nitrogen balance index (NBI), flavonol, anthocyanin, and chlorophyll), leaf area, leaf temperature and color values (L*, a) *, b * C and Hue° were examined. All EB applications increased the plant height and leaf area. Also, the majority of EB isolates enhanced the root dry weight. The effect of EB applications on flavonol and chlorophyll content was not found statistically significant. However, there was a statistically significant increase in the nitrogen balance index (NBI). It was also observed that EB applications caused changes in plant color. According to the results obtained, it has been seen that it is possible to produce environmentally friendly and sustainable medicinal sage with appropriate plant-bacteria combinations.

Bu çalışma, Echinacea purpurea L.’da PEG 6000 ile oluşturulan farklı ozmotik basınçta (kontrol,-0.5 MPa, -1.0 MPa ve -1.5 MPa) kuraklık stresi ile deniz yosunu (Ascophyllum nodosum) uygulamalarının (kontrol, 2, 4 ve 6 cc/l) bazı fizyolojik parametreler üzerindeki etkilerini belirlemek amacıyla yapılmıştır. Ekinezya bitkisinin yaprak alanı, yaprak klorofil miktarı, yaprak dokularında iyon sızıntısı, malondialdehit düzeyi (MDA), yaprak dokularında bağıl su içeriği ve yaprak dokularında membran dayanıklılık indeksi gibi parametreler incelenmiştir. Araştırma sonucunda; kuraklık stresinin bitkinin yaprak alanı, yaprak dokularında bağıl su içeriği ve membran dayanıklılık indeksini azalttığı, MDA düzeyi ve yaprak dokularında iyon sızıntısı miktarında ise artışlara neden olduğu belirlenmiştir. Kuraklık stresinin yaprak klorofil oranı üzerine ise önemli bir etkisi bulunmamıştır. Deniz yosunu ile kuraklık stresinin bitki üzerindeki olumsuz etkileri azaltılmıştır. Deniz yosunu uygulamalarının, MDA düzeyi ve yaprak dokularında iyon sızıntısı hariç incelenen yaprak klorofil oranı ve membran dayanıklılık indeksi üzerindeki etkisi olumlu ve arttırıcı yönde olmuştur. Deniz yosunu uygulamaları, yaprak dokularında bağıl su içeriği ile yaprak alanı gibi parametreleri etkilememiştir.

In the study, humic acid was applied to soybean (Glycine max L.), which has high economic value and importance, to determine the tolerance level of the plant against salt stress, and physical and chemical changes in the plant were observed. The study was carried out in the climate room of Van Yuzuncu Yil University Faculty of Agriculture, Department of Field Crops in 2019. In the research, İlksoy soybean variety was used. The experiment was carried out in 4 factorial orders according to the factorial experiment was designed based on Completely Randomized Design. In the research, four different Humic acid doses (0, 500, 1000 and 2000 ppm) and 3 different NaCl salt doses (0, 125 and 250 mM) were used. In the study, root length, stem length, root fresh weight, stem fresh weight, root dry weight, stem dry weight, leaf area, chlorophyll content, ion leakage in leaf tissues, lipid peroxidation level (MDA), relative water content and membrane resistance index in leaf tissues were determined. Properties such as index were also examined. As a result of the study, the longest root was 38 cm for the control plots that salt and humic acid didn’t apply to the plants. The highest root fresh weight was 2.08 g and the stem fresh weight was 1.87 g of the plots where 500 ppm humic acid dose applied. In addition, the plants with the highest chlorophyll ratio was 51.05 under 250 mM salt applied without humic acid application.