Serkan Erdal

Acceleration of Germination and Early Growth of Wheat and Bean Seedlings Grown Under Various Magnetic Field and Osmotic Conditions

Magnetic field (MF) can have different effects on plant metabolism depending on its application style, intensity, and environmental conditions. This study reports the effects of different intensities of static MF (4 or 7 mT) on seed germination and seedling growth of bean or wheat seeds in different media having 0, 2, 6, and 10 atmosphere (atm) osmotic pressure prepared with sucrose or salt. The germination percentages of the treated seeds were compared with untreated seeds germinated in different osmotic pressure during 7 days of incubation. The application of both MFs promoted the germination ratios of bean and wheat seeds, regardless of increasing osmotic pressure of sucrose or salt. Growth data measured on the 7th day showed that the treated plants grew faster than control. After 7 days of incubation, the mean length of treated seedlings was statistically higher than control plants in all the media. The greatest germination and growth rates in both plants were from the test groups exposed to 7 mT MF. Strikingly, effects of static MF on germination and growth increased positively with increasing osmotic pressure or salt stress compared to their respective controls. On the other hand, MF application caused an increase in dry biomass accumulation of root and shoots of both seedlings; however, this effect was found statistically important in all the conditions for wheat but not for bean, in general.

Androsterone-induced molecular and physiological changes in maize seedlings in response to chilling stress.

The aim of study was to elucidate the influence of foliar sprays of androsterone in alleviating detrimental effects of chilling stress in maize seedlings. Eleven-days-old maize seedlings were treated with 10(-9) mol L(-1) androsterone and then transferred to a chamber with temperature of 10/7 °C (day/night) for 3 days. The stress injury was measured in terms of increase in electrolyte leakage, superoxide production and hydrogen peroxide level, and decrease in chlorophyll content. Androsterone application mitigated significantly the chilling-induced stress injury. Under chilling stress, the oxidative damage which was measured as malondialdehyde content was lesser in androsterone-applied seedlings that were associated with greater activities of superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (POX), ascorbate peroxidase (APX) and glutathione reductase (GR). Moreover, SOD, POX and APX isozymes exhibited a strong correlation with changes in their activities. Androsterone application enhanced the level of antioxidant compounds like ascorbic acid, glutathione, proline and carotenoid as well as activities of antioxidant enzymes. Similarly, while androsterone treatment increased total antioxidant status, it reduced total oxidant status relative to chilling-stressed seedlings alone. Soluble protein profile was significantly changed by only chilling stress and chilling stress plus androsterone treatment, as well. According to these findings, it is possible to say that androsterone could be used to alleviate the damaging effects of chilling stress by improving antioxidative system in maize seedlings. This is the first study elucidating the effects of androsterone on resistance to chilling stress of plants.

Alleviation of salt stress in wheat seedlings by mammalian sex hormones.

BACKGROUND Salinity is one of the most serious constraints facing agriculture today. Some mechanical, chemical and biological approaches are being pursued to cope with soil salinity. Although exogenously treated mammalian sex hormones (MSHs), progesterone, β-estradiol and androsterone, activate significant effects in various biological aspects in plants growing under normal conditions, there is no report investigating their effects on plants growing under salt stress. The present study aimed to investigate whether MSHs could alleviate the destructive effect of salt stress on wheat seedlings and thereby increase their salt tolerance. Wheat leaves were sprayed with 10(-6), 10(-8) and 10(-10) mol L(-1) concentrations of MSH on the ninth day after sowing. MSH-treated seedlings (10-day-old seedlings) were subjected to salt stress for 5 days (between days 10 and 15). RESULTS At all the concentrations tested, MSH treatment provided a significant protection against to detrimental effects of salt stress in wheat seedlings. It improved dry weight, sugar, proline, protein, chlorophyll and glutathione contents in comparison to salinity alone. Similarly, superoxide dismutase, peroxidase, catalase, ascorbate peroxidase and nitrate reductase activities also were augmented by MSH treatment. On the other hand, increases in lipid peroxidation level, superoxide production and hydrogen peroxide content arising from salt treatment were reduced by MSH treatment. The highest salt tolerance was obtained at the concentrations of 10(-6) mol L(-1) for progesterone and 10(-8) mol L(-1) for β-estradiol and for androsterone. CONCLUSION MSHs could be used effectively to protect wheat seedlings from the destructive effects of salt stress by stimulating both enzymatic and non-enzymatic antioxidant mechanism and by promoting levels of osmotic protectants such as proline and sugars resulting in osmotic adjustment, carbon storage and radical scavenging in plants.

Effects of cement flue dust from a cement factory on stress parameters and diversity of aquatic plants

Cement kiln dusts, made of a complex mixture of elements, include high levels of heavy metals such as fluoride, magnesium, lead, cadmium, nickel, zinc, copper, beryllium and some toxic compounds. Because of the toxic element compositions and radioactive isotope properties of cement kiln dusts, not only terrestrial but also aquatic ecosystems are subjected to greater stress. In the present paper, we investigated the effects of pollution caused by Askale-Erzurum cement factory (CF) on the stress parameters and diversity of aquatic plants. For this purpose, aquatic plant species were collected from the outer zone of the CF. Only three (Lemna minor, Ceratophyllum submersum and Potamogeton natans) of these species were able to be determined in the CF zone. Antioxidant enzyme activities of the collected aquatic plants were measured and compared to their controls. Superoxide dismutase (SOD) activity of P. natans in the CF zone was significantly high compared to their respective control, while it was low in L. minor and C. submersum compared to their controls. Similarly, peroxidase (POX) activity of P. natans was high, while those of L. minor and C. submersum were low compared to their respective controls. On the other side, while catalase (CAT) activities of L. minor and C. submersum were low, that of P. natans did not show an important change compared to their respective controls. Furthermore, we found that hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels of all the studied plants were also very high compared to their controls. According to these results, it is clear that pollution caused by the CF reduced diversity and number of aquatic plant species. Besides, the obtained data revealed that P. natans have a more resistant defense system than other species.

Production of carotenoids by Rhodotorula glutinis MT-5 in submerged fermentation using the extract from waste loquat kernels as substrate

BACKGROUND The aim of present study was to investigate the feasibility of the hydrolysate extracts from waste loquat kernels as substrate in submerged culture of yeast Rhodotorula glutinis MT-5 for carotenoid production. RESULTS Loquat kernel was found to have high protein (22.5%) and total carbohydrate (71.2%) contents. Dried and powdered loquat kernels were subjected to acid hydrolysis with 2 mol L⁻¹ HCl. The hydrolysate obtained was used for the preparation of loquat kernel extract and detoxified loquat kernel extract. The detoxification of hydrolysate was performed with Ca(OH)₂. Among the 10 R. glutinis isolates, the MT-5 was found to be best in order to produce carotenoid using the extract as substrate. Production media prepared with detoxified loquat kernel extract or loquat kernel extract gave maximum biomass concentrations of 12.64 and 11.37 g L⁻¹, and maximum carotenoid concentrations of 72.36 and 62.73 mg L⁻¹, respectively. CONCLUSION This study has provided effective processes for the conversion of waste material of plant origin to the extracts which are very rich in term of total fermentable sugar. The practicability of the extracts as fermentation substrate was proven in carotenoid production. To the best of our knowledge, this is the first report on use of this waste material as a substrate in yeast fermentations.

Exogenous mammalian sex hormones mitigate inhibition in growth by enhancing antioxidant activity and synthesis reactions in germinating maize seeds under salt stress

BACKGROUND Mammalian sex hormones (MSH)-progesterone, β-estradiol and androsterone-enhance plant growth and development by stimulating significant morphological and biochemical parameters under normal conditions. However, there is no report regarding their effects on plants exposed to environmental stress conditions. Therefore, the present study was focused on elucidating the possible positive effects of MSH on seedling growth, antioxidant activity and synthesis reactions in maize seeds exposed to salt stress, one of the most important environmental stresses. For this purpose, the various concentrations (10⁻⁶, 10⁻⁸, 10⁻¹⁰ and 10⁻¹² mol L⁻¹) of MSH were studied. RESULTS Salinity (100 mmol L⁻¹ NaCl) significantly reduced root length and seedling height, whereas MSH treatment significantly ameliorated the adverse effects of salinity on root length and seedling height. On the other hand, although salinity increased soluble protein, soluble sugar and proline content in 7-day-old maize seedlings, these were higher in MSH-treated seedlings. Similarly, MSH treatment augmented superoxide dismutase, peroxidase and catalase activities under salt stress, whereas it decreased superoxide production and lipid peroxidation level. The most favorable concentrations were determined as 10⁻⁸ mol L⁻¹ for progesterone and β-estradiol and 10⁻¹⁰ mol L⁻¹ for androsterone. CONCLUSION Exogenous MSH application was found to have an important ameliorative effect on growth of seeds exposed to salt stress by stimulating antioxidant activity and synthesis reactions. This is the first study investigating the effects of MSH on germination of seeds exposed to stress conditions.

Reactive dye bioaccumulation by fungus Aspergillus niger isolated from the effluent of sugar fabric-contaminated soil

The present study dealt with the decolorization of textile dye Reactive Black-5 by actively growing mycelium of Aspergillus niger MT-1 in molasses medium. It was found that the fungus, which was isolated from the effluent of sugar fabric-contaminated soil, was capable of decolorizing the Reactive Black-5 dye in a wide range of temperature, shaking speed and pH values. The experiments also revealed that highest dye decolorization efficiency was achieved with cheap carbon (molasses sucrose) and nitrogen (ammonium chloride) sources. Under the optimized culture conditions, the complete decolorization (100%) of 0.1 g/L dye was achieved in 60 hours. The dominant mechanism of dye removal by the fungus was found to be probably bioaccumulation. Fungal growth in small uniform pellet form was found to be better for dye bioacumulation. Molass as carbon source increased dye bioaccumulation by stimulating the mycelial growth in small uniform pellet form. The maximum bioaccumulation efficiency of fungus for dye was 91% (0.273 g bioaccumulated dye) at an initial dye concentration of 0.3 g/L in 100 hours. It was shown for the first time in the present study that the effluent of sugar fabric-contaminated soil was a good source of microorganisms, being capable of decolorizing snythetic textile dyes.

Effects of extremely low magnetic field on the production of invertase by Rhodotorula glutinis

Invertase is an important enzyme used in many fields especially in food industry to produce fructose syrups. The current study focused on increasing invertase production by exposing Rhodotorula glutinis to extremely low magnetic fields (ELMF; 0 and 7 mT). For this purpose, the microorganism was allowed to grow in normal magnetic field and ELMF for 72 hours at the same temperature (24 ± 2°C). The fermentation was carried out in submerged culture for 120 hours. The results showed that invertase production is strongly dependent on the growth conditions of the microorganism. Both of the different magnetic fields applied to R. glutinis increased invertase production ranged from 48%-67% when compared with the control. On the other hand, ELMF treatment increased biomass formation about 14%-28% when compared with the control. As a result, magnetic field treatment could effectively be used in the production of invertase by R. glutinis.

Progesterone and β-Estradiol Stimulate Seed Germination in Chickpea by Causing Important Changes in Biochemical Parameters

Effects of progesterone and β-estradiol on morphologic (germination velocity, root and shoot length) and biochemical (activities of α-amylase, superoxide dismutase, peroxidase and catalase, H2O2 content, lipid peroxidation) parameters during germination and post-germination stages of chickpea seeds were studied. The seeds germinated at various hormone concentrations (10 - 4, 10 - 6, 10 - 9, 10 - 12, 10 - 15 M) were harvested at the end of the 1st, 3rd, and 5th day. With comparison to the control, these hormones caused an increment in the number of germinating seeds at the end of days 1 and 3 by accelerating the seed germination. Root and shoot lengths were augmented by both hormones at all hormone concentrations tested. The highest elongation was recorded in 10 - 6 M progesterone and 10 - 9 - 10 - 12 M β-estradiol. Similarly, activities of α-amylase and superoxide dismutase were increased by all concentrations of both hormones, and maximum increases were obtained with 10 - 6 M progesterone and 10- 9-10- 12 M β-estradiol. In the case of superoxide dismutase activity, not only the H2O2 content but also the peroxidase and catalase activities increased. Lipid peroxidation decreased depending on an increase in the antioxidant enzyme activities. In the present study, it was demonstrated that progesterone and β-estradiol even at low concentrations increase the germination velocity and resistance to stress conditions by changing the activities of some biochemical pathways.

Comparative evaluation of oxidative enzyme activities during adventitious rooting in the cuttings of grapevine rootstocks.

BACKGROUND This study investigated changes in peroxidase (POX) and polyphenol oxidase (PPO) activities through adventitious rooting in hardwood cuttings of grapevine rootstocks. Three grapevine rootstocks with different propensity to produce adventitious roots were selected: recalcitrant (Ramsey), non-recalcitrant (Rupestris du Lot) and intermediate (99R) cultivars. RESULTS The averages of root number at 65 days were 96 in Lot, 76 in 99R and 30 in Ramsey. Both enzyme activities characteristically increased before adventitious rooting, regardless of rooting ability of the rootstocks, and then decreased. POX activity increased in Ramsey cuttings at 22 days, in Lot and 99R cuttings at 14 days after planting, and then decreased gradually until 51 days. The highest POX activity was determined in Ramsey rootstock with the highest rooting ability and the lowest activity was determined in the rootstocks with the lowest rooting ability. PPO activity gradually increased in Ramsey rootstock cuttings from 10 days to 22 days, in Lot and 99R cuttings at 14 days, and then decreased until 51 days. A significant correlation was identified between high POX activity and adventitious rooting capability in rootstocks, but the same result was not determined with PPO activity. CONCLUSION A recalcitrant rooting variety cannot increase POX activity sufficiently before rooting. Therefore applications that could increase POX activity in stem cuttings during rooting may facilitate increased rooting in such rootstocks.