Atilla Dursun

Calcium and humic acid affect seed germination, growth, and nutrient content of tomato (Lycopersicon esculentum L.) seedlings under saline soil conditions

The effects of calcium and humic acid on seed germination, growth and macro- and micro-nutrient contents of tomato (Lycopersicon esculentum L.) seedlings in saline soil conditions were evaluated. Different levels of humic acid (0, 500, 1000 and 2000 mg kg−1) and calcium (0, 100, 200 and 400 mg kg−1) were applied to growth media treated with 50 mg NaCl kg−1 before sowing seeds. Seed germination, hypocotyl length, cotyledon width and length, root size, shoot length, leaf number, shoot and root fresh weights, and shoot and root dry weights of the plant seedlings were determined. Macro- and micro-nutrient (N, P, K, Ca, Mg, S, Cu, Fe, Mn and Zn) contents of shoot and root of seedlings were also measured. Humic acid applied to the plant growth medium at 1000 mg kg−1 concentration increased seedling growth and nutrient contents of plants. Humic acid not only increased macro-nutrient contents, but also enhanced micro-nutrient contents of plant organs. However, high levels of humic acid arrested plant growth or decreased nutrient contents. Levels of 100 and 200 mg kg−1 Ca2+ application significantly increased N, Ca and S contents of shoot, and N and K contents of root.

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.

Identification of Resistance to Common Bacterial Blight Disease on Bean Genotypes Grown in Turkey

Common bacterial blight (CBB) in edible beans (Phaseolus vulgaris), incited Xanthomonas campestris pv. phaseoli, reduces bean yields and seed quality. The main objective of this study was to determine resistance to common bacterial blight in bean genotypes. Twenty-two bean genotypes grown in Turkey including common and snap bean cultivars/lines were collected from different parts of Turkey and tested for resistance against to Xanthomonas campestris pv. phaseoli strain MFD-11. All the common and snap bean lines/cultivars tested were moderately susceptible, susceptible or highly susceptible, except AG-7117 which was found resistant to Xanthomonas campestris pv. phaseoli. This is the first report of a resistance source in a common bean line (AG-7117) against Xanthomonas campestris pv. phaseoli.

Sewage sludge as a substitute for mineral fertilization of spinach (Spinacia oleraceae L.) at two growing periods

Abstract.

Roles of glycine betaine in mitigating deleterious effect of salt stress on lettuce (Lactuca sativa L.)

This study was conducted to evaluate the roles of glycine betaine (GB) in mitigating deleterious effect of salt stress on lettuce. Lettuce plants were subjected to two salinity (0 and 100 mmol l−1 NaCl) and four GB levels (0, 5, 10, 25 mmol l−1). Salinity resulted in a remarkable decrease in growth parameters, relative leaf water content and stomatal conductance. Plants subjected to salt stress exhibited an increase in membrane permeability (MP), lipid peroxidation (MDA), leaf chlorophyll reading value, H2O2 and sugar content. Exogenous foliar applications of GB reduced MP, MDA and H2O2 content in salt-stressed lettuce plants. Salt stress increased Na and generally decreased other nutrient elements. GB reduced Na accumulation, but significantly increased other element contents under salinity conditions. The study showed that gibberellic acid (GA) and salicylic acid (SA) content in salt-stressed plants were lower than those of nonstressed plants. However, salinity conditions generally increased the abscisic acid content. GB treatments elevated the concentrations of GA, SA and indole acetic acid (IAA) at especially 10 and 25 mmol l−1 GB under salt stress conditions. It could be concluded that exogenous GB applications could ameliorate the harmful effects of salt stress in lettuce.

Exogenously applied glycine betaine regulates some chemical characteristics and antioxidative defence systems in lettuce under salt stress

We investigated the effects of exogenous glycine betaine (GB) applications on antioxidant enzyme activity, dry matter, and the contents of organic acids, amino acids, total antioxidants, and total phenolics in lettuce, Lactuca sativa, under salt stress. The treatments included four concentrations of GB (0, 5, 10, and 25 mM) and two levels of salinity (0 and 100 mM of NaCl). The 25 mM GB treatment increased dry matter and the content of total phenolics in lettuce plants compared to the non-GB-treated plants under salt stress. Salinity (100 mM NaCl without GB) significantly reduced dry matter, total phenolic content, and total antioxidant content in the plants. However, the lettuce plants grown under salt stress generally had higher amino acid and organic acid contents than those grown under non-salinity conditions. GB treatments had different effect on amino acid and organic acid contents under salinity conditions. Superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) activities were elevated under the 100 mM NaCl and 0 mM GB treatments, whereas higher concentrations of GB decreased them under salt stress. The 25 mM GB treatment mitigated the negative effect of salt stress and increased the dry matter by 44% compared to the plants that were treated with 100 mM NaCl and 0 mM GB. The results suggested that exogenous GB treatments could ameliorate the tolerance of lettuce to salt stress by increasing the total antioxidants and total phenolics, and regulating antioxidant enzyme activity, and altering the contents of organic acids and amino acids.

Responses to the Irrigation Water Amount of Spinach Supplemented with Organic Amendment in Greenhouse Conditions

The effect of organic amendment applications on some agrophysiological properties of pot-grown spinach was investigated under drought stress. The I1, I2, I3, and I4 irrigation treatments received water amounts up to 100, 80, 60, and 40 percent of evaporation from a reduced pan, respectively. A liquid organic amendment was applied to spinach seeds as seed treatment at the ratios of 0.1 percent (H1) and 0.2 percent (H3). Furthermore, in the H2 and H4 treatments the amendment was foliar applied to spinach seedlings at the ratios of 0.1 percent and 0.2 percent in addition to the seed treatments, respectively. Organic amendment treatments positively affected root and leaf growth. The plants responded to water stress by lower growth. Leaf relative water content, membrane permeability, chlorophyll reading, and stomatal conductance values also indicated significant changes. These results support the view that organic amendment application increased growth. However, it could not provide a significant contribution for growth under water stress.

Integrated Use of Nitrogen Fertilization and Microbial Inoculation: Change in the Growth and Chemical Composition of White Cabbage

ABSTRACT Field experiments were conducted to evaluate the impact of seed and seedling inoculation by plant growth promoting rhizobacteria (PGPR) on nitrogen use efficiency, growth, yield, and chemical composition of cabbage at varying levels of nitrogen (N). Data revealed that N alone or in combination with PGPR either as seed or seedling inoculation significantly improved growth, yield, and nutrients of cabbage. PGPR inoculations were more efficient than non-inoculated controls in terms of yield and yield parameters. This study showed that seed and seedling inoculation increased yield and yield parameters as well as chlorophyll reading value and stomatal conductance versus controls. Applications of mineral fertilizers with microbial applications save 25% of mineral fertilizers yet give 33% more yield versus full doses of mineral application without microbial applications. Both seed and seedling treatments increased the nitrogen use efficiency (NUE) rates by 45, 53, 58, 45, and 40%, and 49, 59, 68, 69, 60, and 55%, respectively.

Bitki Genetik Mühendisliği ve Ekonomik Öneme Sahip Bazı Bitkilerde Genetik Mühendisliği Uygulamaları / Plant Genetic Engineering and Its Applications on Economically Important Plants

OZET: Yaklasik 100 yil once baslayan islah calismalari sayesinde, bitkilerde verim, kalite ile birlikte bircok hastalik ve zararlilara dayaniklilik gibi konularda onemli gelismeler saglanmistir. Otuz yil oncesine kadar, bitki cesitleri klasik islah metotlari uygulanarak gelistirilmekteydi. Ancak, bu gelisme hizi bitkilerde mevcut genetik varyasyonun daralmasi nedeniyle oldukca yavaslamistir. Daha ileri basarilar icin, bitki islahcilari uygun yeni teknikleri almak ve bunu eldeki mevcut tekniklere adapte etmek zorundadirlar. Son yillarda gelisen “Bitki Molekuler Biyolojisi”, analitik prosedurler ve yeni teknolojiler sayesinde, yeni bitki cesitlerinin islahi yonunde umitvar gelismeler olmustur. Agrobacterium ve direkt gen transfer sistemleri, degisik bitki turlerine gen transferinde yaygin olarak kullanilmaktadir. Bu uygulamalar sonucu, hastalik ve zararlilara dayanikli bitkilerin elde edilmesi, erkek kisir bitkilerin elde edilmesi, bitkilerde yaprak sararmasinin geciktirilmesi, karbon metabolizmasinin modifikasyonu, antisens RNA teknolojisi, yag asidi iceriginin modifikasyonu, degisik renk ve ozellikte ciceklerin uretimi, patateslerde depolama suresinin uzatilmasi ve besin degerinin artirilmasi, stres faktorlerine (kuraklik, don vs.) dayanikliligin artirilmasi mumkun olmustur. Transgenik bitkilerin genis alanlarda ticari olarak tarimi yapilmadan once, bu bitkilerin ve urunlerinin cevre ve diger organizmalarla olan interaksiyonlarinin test edilmesi ve tuketici tercihlerinin de mutlaka goz onune alinmasi gerekmektedir. Anahtar kelimeler: Bitki gentik muhendisligi ve uygulamalari Plant Genetic Engineering and Its Applications on Economically Important Plants ABSTRACT: Plant breeding programs which began nearly a century ago, have made steady improvements in productivity, quality and adequate resistance to numerous diseases and insect pests. Until three decade ago, plant varieties have been developed using conventional methods. However, the rate of this program have slowed down drastically due to the narrowed genetic variation of the crops. In order to be successful, breeders must adapt and incorporate suitable techniques as they become available. The improvement in plant molecular biology, analytical procedures, instrumentation and computation that have occurred during the last decade promise to speed up greatly the development of new cultivars. Agrobacterium and direct gene transfer systems are now used widely to introduce foreign genes into large number of plant species. The availability of these gene transfer systems and successful strategies in plant genetic engineering resulted in the production of pest and disease resistant plants, male sterile plants, delaying of leaf senescence, modification of carbon metabolism, antisense RNA technology, modification of fatty acid composition, production of different colored and patterned flowers, development of storage characteristics and quality of potato tubers, production of stress resistant plants. Before transgenic plants are commercially grown, interactions of transgenic crops and their products with environment and with other organisms should be tested and consumer preference should also be taken account. Key words: Plant Genetic Engineering and Its Application