Aslihan Esringü

Effects of Boron Fertilizer on Tomato, Pepper, and Cucumber Yields and Chemical Composition

In many parts of the world, boron (B) levels are insufficient for potential production. Boron deficiency is also widespread in the Anatolia region of Turkey. Boron deficiency could impact production and quality of tomatoes (Lycopersicon esculentum L.), pepper (Capsicum annum L.), and cucumber (Cucumis sativus L.). A two-year greenhouse experiment was conducted to study yield and quality response of three vegetables to B addition (0, 1, 2, 3, and 4 kg B ha−1). The optimum economic B rates (OEBR) were 2.3, 2.6, 2.4 kg B ha−1, resulting in soil B concentrations of 0.33, 0.34 and 0.42 mg kg−1. Independent of plant species, B application decreased tissue nitrogen (N), calcium (Ca), and magnesium (Mg) but increased tissue phosphorus (P), potassium (K), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) concentrations. We conclude that a B addition of 2.5 kg ha−1 is sufficient to elevate soil B levels to nondeficient levels. Similar studies with different soils and initial soil-test B levels are needed to conclude if these critical soil test values and OEBR can be applied across the region.

Effects of sodium nitroprusside (SNP) pretreatment on UV-B stress tolerance in lettuce (Lactuca sativa L.) seedlings

Ultraviolet-B (UV-B) radiation is one of the most important abiotic stress factors that could influence plant growth, development, and productivity. Nitric oxide (NO) is an important plant growth regulator involved in a wide variety of physiological processes. In the present study, the possibility of enhancing UV-B stress tolerance of lettuce seedlings by the exogenous application of sodium nitroprusside (SNP) was investigated. UV-B radiation increased the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD) and total phenolic concentrations, antioxidant capacity, and expression of phenylalanine ammonia lyase (PAL) gene in seedlings, but the combination of SNP pretreatment and UV-B enhanced antioxidant enzyme activities, total phenolic concentrations, antioxidant capacity, and PAL gene expression even more. Moreover, UV-B radiation significantly inhibited chlorophylls, carotenoid, gibberellic acid (GA), and indole-3-acetic acid (IAA) contents and increased the contents of abscisic acid (ABA), salicylic acid (SA), malondialdehyde (MDA), hydrogen peroxide (H2O2), and superoxide radical (O2•−) in lettuce seedlings. When SNP pretreatment was combined with the UV-B radiation, we observed alleviated chlorophylls, carotenoid, GA, and IAA inhibition and decreased content of ABA, SA, MDA, H2O2, and O2•− in comparison to non-pretreated stressed seedlings.

Boron application improves on yield and chemical composition of strawberry

Abstract Boron (B) is an essential micronutrient required for normal plant growth and development. Boron management is challenging because the optimum B application range is narrow and the application rates vary from one soil to another. Boron deficiency is widespread in the Anatolia region of Turkey. This may impact on yield and mineral contents of leaves and fruits of strawberry (Fragaria×ananassa cv. Fern) especially in B-deficient calcareous Aridisols in Eastern Anatolia, Turkey. A 2-year field experiment was conducted to study yield and quality response of strawberry to B application. Boron fertilizer application affected plant yield and chemical composition. B application decreased tissue nitrogen (N) and calcium (Ca) but increased tissue phosphorus (P), potassium (K), manganese (Mn), zinc (Zn) and copper (Cu) content. We conclude that a B addition of 5.5 kg ha−1 is sufficient to elevate soil B levels to non-deficient levels.

Boron fertilization of Mediterranean aridisols improves lucerne (Medicago sativa L.) yields and quality

Abstract Lucerne (Medicago sativa L.) is grown as a forage crop on many livestock farms. In calcareous soils in eastern Turkey, lucerne production requires boron (B) addition as the soils are naturally B deficient. Field experiments with four B-application rates (0, 1, 3, and 9 kg ha−1 B) were conducted in 2005 and 2006 to determine the optimum economic B rate (OEBR), critical soil test and tissue B values for dry matter (DM) production for lucerne grown on B-deficient calcareous aridisols in eastern Turkey. Boron application increased yield at each site in both years of production. The OEBR and critical soil and tissue B content were not impacted by location. Averaged over the two years and three locations, the OEBR was 6.8 kg B ha−1 with an average DM yield of 12.0 Mg ha−1. The average soil B content at the OEBR was 0.89 mg kg−1 while leaf and shoot tissue B content amounted to 51.8 and 35.5 mg kg−1, respectively. Boron application decreased tissue calcium (Ca), zinc (Zn), and copper (Cu), and increased tissue nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), iron (Fe), and manganese (Mn). Tissue and soil B increased without impacting yield at B levels up to 9 kg ha−1. We conclude that 7 kg ha−1 B is sufficient to elevate soil test B levels from 0.11 to 0.89 mg kg−1 and overcome B deficiency at each of the sites in the study. Similar studies with different soils and initial soil test B levels are needed to conclude if these critical soil and tissue values can be applied across the region.

Roles of Bacillus megaterium in Remediation of Boron, Lead, and Cadmium from Contaminated Soil

Phytoremediation is an attractive, economical alternative to soil removal and burial methods to remediate contaminated soil. The objective of this study was to investigate the effects of adding different rates of Bacillus megaterium on the capacity of Brassica napus plants to take up boron (B), lead (Pb), and cadmium (Cd) from polluted soils under field conditions. Field experiments were conducted using a randomized complete block design with control (without pollution and B. megaterium application) and B, Pb, and Cd in two doses (0 and 100 mg kg−1), B. megaterium with four doses (no application and 108 cfu B. megaterium ml−1 sprayed at 50 ml plot−1, 100 ml plot−1, 150 ml plot−1). Results indicated that soil pollution treatments significantly decreased seed (SDMY), shoot (SHDMY), root (RDMY), and total dry-matter yield (TDMY) of plants at 42.9, 3.8, 62.6, and 23.4% for B-polluted treatment; 25.8, 8.7, 17.6, and 14.2% for Pb-polluted treatment; and 33.2, 7.0, 14.0, and 16.4% for Cd-treatment without B. megaterium application, respectively. However, the application of B. megaterium ameliorated the negative effects of B, Pb, and Cd at 41.4, 52.7, and 10.9% for B; 24.4, 21.6, and 4.9% for Pb; and 22.8, 22.0, and 3.3% for Cd, respectively. The potentially bioavailable and relatively available fraction of soil B, Pb, and Cd increased with increases in the B. megaterium application but total fraction and stable fraction decreased. It is concluded that the seed and shoot parts of B. napus can be used as hyperaccumulators for plant B, Pb, and Cd remediation according to remediation factors but the shoot is the biggest part of the plant, and thus an important portion of the plant to remove B, Pb, and Cd from the B-, Pb-, and Cd-contaminated soils. To decrease desired concentration for 8 mg B kg−1, 4 mg Pb kg−1, and 3 mg Cd kg−1 in the active rooting zone of soil, approximately 2, 6, and 21 years would be necessary with only 150 ml plot−1 B. megaterium–sprayed soil cultivated with B. napus, respectively.

Ameliorative Effect of Foliar Nutrient Supply on Growth, Inorganic Ions, Membrane Permeability, and Leaf Relative Water Content of Physalis Plants under Salinity Stress

The effects of nutrients foliarly applied at varying doses were investigated on some agrophysiological properties, such as dry matter, nutrient content, chlorophyll content, membrane permeability, and leaf relative water content, of physalis (Physalis ixocarpa) plants under salinity stress. Plant shoot fresh weight, dry weight, plant length, and chlorophyll contents were reduced by 54.0–61.8%, 53.4–64.8%, 38.3–47.0%, and 26.5–40.0%, respectively, at 60 and 120 mM (without foliar application) compared to the nonsaline treatment [0 mM sodium chloride (NaCl)]. However, the membrane permeability (MP) of the plants increased with increasing salinity. Ion balance in plant cells is very important to plant growth and tolerance of salinity. So, foliar application alleviates to some extent the deleterious effects of salinity stress on growth and growth parameters, depending on nutrient concentration in plant. The greatest mitigating effects of foliar fertilizer for chlorophyll, shoot fresh weight, leaf relative water content, and MP at high-salinity-stress conditions (60 and 120 mM) were obtained from a 10-mM foliar magnesium nitrate [Mg(NO3)2] application at the ratios 57.2–62.6%, 49.0–30.9%, 27.5–28.9%, and 33.0–19.6%, respectively, but 10-mM foliar calcium nitrate [Ca(NO3)2] application was most effective for plant shoot dry weight and plant height at 60 and 120 mM salinity stress conditions. These results support the view that supplementary Mg(NO3)2 and Ca(NO3)2 application can overcome the effects of high salinity on plant growth and growth parameters under saline conditions.

Ameliorative Effect of Humic Acid and Plant Growth-Promoting Rhizobacteria (PGPR) on Hungarian Vetch Plants under Salinity Stress

ABSTRACT Salinity is one of the major abiotic stress factors for cultivated plants, limiting their growth and productivity in many areas of the world. This study aims to determine the ameliorative effects of humic acid (HA) and plant growth-promoting bacteria (PGPR) on amino acids, enzymes, minerals, organic acids and hormones in Hungarian vetch (Vicia pannonica) plants under salinity stress conditions. Salinity stress was established by adding 0, 10, 30 and 60 mM of sodium chloride (NaCl) to growing media. HA and PGPR treatments had positive ameliorative effects on the minerals, organic acids, hormones and enzyme activity of Hungarian vetch plants under salinity stress conditions. PGPR treatments showed better ameliorative effects than HA. This study suggests that PGPR treatments have the potential to be used as alleviator fertilizer in salinity stress conditions and may have ameliorated the deleterious effects of salt stress on Hungarian vetch plants.

OPTIMUM ECONOMIC BORON FERTILIZER DOSES OF WHEAT GROWN ON CALCAREOUS SOIL

Field experiments with boron (B) (0, 1, 3, 6, and 9 kg ha−1 B) were conducted in 2005 and 2006 to determine the optimum economic B rate (OEBR). Critical soil test and tissue B values for grain yield (GY) and total yield (TY) production for ‘Krik’ cv. and ‘Bezostiya’ cv. grown on B-deficient calcareous Aridisols in Eastern Turkey were determined. Averaged over the two years, ‘Krik’ and ‘Bezostiya’ cvs., the OEBR was 6.4–5.6 kg B ha−1 with an average GY yield of 2.0–3.8 Mg ha−1, and 5.9–5.6 kg B ha−1 with an average TY yield of 5.5.0–10.8 Mg ha−1, respectively. The average soil B content at the OEBR was 1.15–0.92 mg kg−1 while leaf tissue B content amounted to 24.0 and 30.3 mg kg−1 for ‘Krik’ and ‘Bezostiya’ cvs., respectively. Boron application decreased tissue calcium (Ca), and magnesium (Mg), and increased tissue nitrogen (N), phosphorus (P), potassium (K), zinc (Zn), iron (Fe), copper (Cu) and manganese (Mn).