Alpaslan Kusvuran

The defensive role of silicon in wheat against stress conditions induced by drought, salinity or cadmium

In the crust of earth, silicon (Si) is one of the two major elements. For plant growth and development, importance of Si remains controversial due to the widely differences in ability of plants to take up this element. In this paper, pot experiments were done to study Si roles in improving salt, drought or cadmium (Cd) stress tolerance in wheat. Up to full emergence, all pots were watered at 100% field capacity (FC) every other day with nutrient solution without any treatments. Fifteen days after sowing, pots were divided into four plots, each with 40 pots for no stress (control) and three stress treatments; drought (50% FC), salinity (200 mM NaCl) and cadmium (2 mM Cd). For all plots, Si was applied at four levels (0, 2, 4 and 6 mM). Under no stress condition, Si applications increased Si content and improved growth as a result of reduced electrolyte leakage (EL), malondialdehyde (MDA) and Na+ contents. Under stress conditions, Si supplementation conferred higher growth, gas exchange, tissue water and membranes stabilities, and K+ content, and had limited MDA and Na+ contents and EL compared to those obtained without Si. Compared to those without Si, enzyme (e.g., superoxide dismutase, catalase and peroxidase) activity was improved by Si applications, which were linked with elevated antioxidants and osmoprotectants (e.g., free proline, soluble sugars, ascorbic acid and glutathione) contents, might providing antioxidant defense against abiotic stress in wheat. The level of 4 mM Si was most effective for mitigating the salt and drought stress conditions, while 6 mM Si level was most influentially for alleviating the Cd stress condition. These results suggest that Si is beneficial in remarkably affecting physiological phenomena and improving wheat growth under abiotic stress.

Effects of sewage sludge used as fertilizer on the yield and chemical contents of common vetch (Vicia sativa L.) and soil

This study was conducted to determine the effects of sewage sludge (SS) used as fertilizer at different concentrations [Control, 20 kg ha–1 nitrogen (N), 30 ton ha–1 SS (S1), 60 ton ha–1 SS (S2) and 90 ton ha–1 SS (S3), 20 kg ha–1 N + 30 ton ha1 SS (N + S1), 20 kg ha–1 N + 60 ton ha–1 SS (N + S2) and 20 kg ha–1 N + 90 ton ha–1 SS (N + S3)] on common vetch yields and chemical features. For this purpose, an increasing level of SS was applied to the soil samples. The residuals of some heavy metal (Hg, Cr, Fe, Ni, Zn, Mn, Cd, Pb, Cu, Co, and Se) and macro element (K, Ca, Na, Mg, C, and S) concentrations were measured in leafs, seeds and soils. According to the results of this study, SS, when applied to soil in increasing amounts, raised the mineral matter contents of the plants, which favorably affected plant growth. Accordingly, it affected the herbage yield, increasing the yield in parallel with the increasing SS concentrations. Applying N with the SS positively influenced the heavy metal contents on leafs and seeds of common vetch and residue in the soil. Besides, the heavy metal contents were found at below critical levels in the soil, leaf and seeds. Therefore, SS application as fertilizer used in appropriate concentrations did not pollute the soil very much, but did lead to an increase in plant products.

The Effects of Salt Stress on the Germination and Antioxidative Enzyme Activity of Hungarian Vetch ( Vicia pannonica Crantz.) Varieties

Among abiotic stresses, salinity is one of the most important affecting agricultural production world-wide. In this study, 5 different salt (NaCl) concentrations (0, 50, 100, 150 and, 200 mM) were investigated on the germination and antioxidative enzyme activity of Hungarian vetch seeds. The germination rates, shoot and root lengths, shoot and root fresh weights, shoot/root ratios, lipid peroxidation (MDA), superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) activities were evaluated and analyzed at 15 days after placing the seeds in petri dishes. The results indicated a significant variation in the germination and early seedling growth characteristic responses of the varieties to NaCl salinity. It was seen that increasing the NaCl concentration resulted in a decrease in the early seedling growth characteristic germination rates and values of all of varieties used in experiment. However, these decreased less in the tolerant varieties than in the sensitive ones. Under stress conditions, the tolerant varieties showed less of an increase in MDA and more of an increase in SOD, CAT, APX, and GR than the intolerant varieties, indicating that saline stress induces the production of reactive oxygen radicals, resulting in an increase MDA and oxidative stress in the varieties. In Hungarian vetch, this increase in the antioxidant enzyme activities is associated with salt stress tolerance. These results might be beneficial in breeding programs relevant to salinity stress resistance.

Assessment of AquaCrop model in the simulation of seed yield and biomass of Italian ryegrass

ABSTRACT Given that the optimal sowing rate and inter-row spacing of Italian ryegrass raised for seed have not been determined, the objective of this research was to assess the effect of crop density on biomass and seed yields under different climate conditions, applying the AquaCrop model. The data came from experiments conducted under moderate continental climate conditions at Stitar (Serbia) and Mediterranean climate conditions at Cukurova (Turkey). At Stitar, there were three different inter-row spacings (high (Sd), medium (Sm) and low (Sw) crop densities), while at Cukurova there was only high crop density (Sn). In the calibration process, the initial canopy cover, canopy expansion and maximal canopy cover were adapted to each crop density, while the other conservative parameters were adjusted to correspond to all climate conditions. Calibration results showed a very good match between measured and simulated seed yields; the values of the coefficient of determination (0.922). The biomass simulation was very good for Cukurova (R2 = 0.97), but somewhat poorer for Stitar (R2 = 0.72). Other statistical indicators were high such as Willmott index of agreement of both the calibrated and validated data sets, for both study areas >0.916 and normalized root mean square error in the range from 9–18%. The AquaCrop model was found to be more reliable for Italian ryegrass biomass and seed yield predictions under mild winter climate conditions, with adequate water supply, compared with moderate climate and water shortage conditions.

Effects of different organic materials on forage yield and nutrient uptake of silage maize (Zea mays L.)

ABSTRACT The use of organic materials as a source of nutrients on agricultural lands ameliorates soil physical properties as well as being an environmentally friendly way of disposing of their wastes. This study was conducted to determine effects of three organic materials (poultry litter, cattle manure, leonardite) on yield and nutrient uptake of silage maize. Poultry litter and cattle manure were applied based on phosphorus (P) or nitrogen (N) requirements of the crop whereas leonardite was applied only one dose (500 kg ha−1) and also combined with three inorganic fertilizer doses (100%, 75%, 50% of recommended inorganic fertilizer dose). According to the results, the highest green herbage yield and nutrient uptake values were observed in LEO-100 whereas N-based treatments significantly decreased yield and nutrient uptake of silage maize. The use of organic materials as a combination with inorganic fertilizer in silage maize cultivation is highly beneficial for sustainable forage production.

Intercropping of Hungarian Vetch ( Vicia pannonica Crantz.) And Barley ( Hordeum vulgare L.) Under Different Plant Varieties and Mixture Rates

This study was conducted to determine the effects of different varieties and mixture ratios on the forage yield and quality of a Hungarian vetch and barley intercropping system at the Middle Kizilirmak Basin of Turkey (40°202 N, 33°582 E, elevation 550 m), during the 2011–2012 and 2012–2013 growing seasons. As per the results averaged over 2 years, the different varieties and mixture ratios had significant effect on the forage yield and quality, and also the interactions for the characters studied were statistically significant. The highest Hungarian vetch rate (37.3%), green herbage (36.3 t ha–1) and crude protein (CP) yields (1510 kg ha–1) were obtained from the mixture of 80% Hungarian vetch (Tarm Beyazi-98) and 20% barley, the highest hay yield (10.5 t ha–1) was obtained from the mixture of 20% Hungarian vetch (Anadolu Pembesi-2002) and 80%barley. In terms of the forage quality parameters, such as crude protein rate (CPR), neutral detergent fiber, acid detergent fiber, and relative feed value, except for the CPR (16%, in 80% Hungarian vetch (Tarm Beyazi-98)+20% barley combination), the most desirable results were assessed (54.6%, 31.3%, and 110%, respectively) from the mixture of 80% Hungarian vetch (Ege Beyazi-79) and 20% barley. The cultivar Tarm Beyazi-98 showed the highest forage yield among the tested cultivars of Hungarian vetch, while cultivar Ege Beyazi-79 had the highest forage quality. Moreover, despite the forage yield having been increased with the increasing barley seed ratio in the mixture, the forage quality significantly decreased concurrently. From the results of the study, it was concluded that the optimal values, both in yield and quality, were obtained from the 80% Hungarian vetch+20% barley intercropping system.

Fatty Acid Compositions of the Seeds of Some Trifolium Species

The Mediterranean region is very rich in Trifolium species, particularly in Turkey where it is common and represented by 103 species [1]. The widespread use of legumes makes this food group an important source of lipid and fatty acids in animal and human nutrition. Some publications related to the total lipid and fatty acid composition have been reviewed by a few researchers [2–8]. An accurate assessment of the profile and percentage total fatty acids from fresh forage is crucial when studying the biohydrogenation of fatty acid from fresh plants [9]. After harvesting, loss of lipids in forages occurs due to the oxidation of unsaturated fatty acids through the activity of plant lipases [10] and lipoxygenases [11], decreasing the amount of unsaturated fatty acids [12]. The aim of the present study was to determine the fatty acid contents of the seeds of T. lappaceum, T. pilulare, T. compastre, T. resupinatum, and T. angustifolium species. The results of the fatty acid analysis are shown in Table 1. The fatty acid composition of some plants used as feed crops from Trifolium species showed different SFA and UFA concentrations. In all the Trifolium studied, linoleic acid was found to be the major component (35.89–68.28%). Linoleic acid was found in the greatest proportion in the seed oil. Among the species, superior linoleic acid content was observed in T. lappaceum (68.28%). The oleic acid content was at the highest level in T. pilulare (41.97%) but at the lowest level in T. resupinatum (13.38%) and T. compastre (16.78%). T. lappaceum and T. angustifolium did not contain any oleic acid. The linolenic acid content was at the highest level in T. angustifolium (12.72%) but at the lowest level in T. pilulare (2.57%). The seed oils of all the species were richer in linoleic acid than linolenic acid. In the study, palmitic acid and stearic acid were found to contain the highest amounts of SFAs. Their contents were observed to be from 16.32 to 20.47% and from 2.87 to 5.83%, respectively. The maximum contents were found in T. resupinatum, while the lowest levels were found in T. compastre as palmitic acid and stearic acid. The TSFA content of Trifolium species was between 19.21 and 27.66%. T. pilulare has the lowest level of saturated acid, while T. resupinatum has the highest amount of SFA (Table 1). However, the UFA concentration of Trifolium species was as high as those reported in other family members of Fabaceae [3, 13, 14], Lamiaceae [15], and Apiaceae [16]. In our study, UFAs largely predominated over SFAs. While the highest content of UFA (80.79%) was found in T. pilulare followed by T. compastre (77.70%), T. lappaceum (74.43%), and T. angustifolium (73.81%), the lowest values were found in T. resupinatum (72.34%). Bakoglu et al. [3] found UFA concentrations of 83.46 and 78.55% in Medicago sativa and Medicago lupiluna, respectively. We have used the biplot to compare Trifolium species on the basis of fatty acid compositions and to identify species or groups of Trifolium that are particularly promising in certain aspects [17]. The biplot displays 80% of information in the standardized data for the five Trifolium species for 14 fatty acids, which is partially presented in Table 1. Interpretation of the biplot also shows that T. pilulare has the highest concentration of oleic acid and TUSFA (Total unsaturated fatty acid). T. resupinatum has the highest levels of myristic acid and palmitic acid. T. compastre has the highest levels of pentadecanoic acid, palmitoleic acid, heptadecanoic acid, gadoleic acid, heneicosanoic acid, linoleic acid, and behenic acid. T. lappaceum and T. angustifolium has the highest contents of stearic acid, linolenic acid, arachidic acid, and TSFA.