Antioxidant Enzyme Activities and Abiotic Stress Tolerance Relationship in Vegetable Crops

Climatic changes can cause serious reductions in yield and crop quality. Under the threat of climatic changes, one of the precautions to cope is selection and development of resistant vegetable genotypes to abiotic stresses. Several physiological and biochemical reactions and different tolerance levels can occur according to plant species. When plants are subjected to environmental stresses such as salinity, drought, temperature extremes, herbicide treatment and mineral deficiency, the balance between the production of reactive oxygen species (ROS) and the quenching activity of antioxidants is upset, often resulting in oxidative damage. Since activated oxygen species can disrupt normal metabolism through oxidative damage to lipids, protein and nucleic acids, plants possess a number of antioxidant enzymes that protect them from these cytotoxic effects. To control the level of ROS and to protect cells under stress conditions, plant tissues contain several enzymes for scavenging ROS. The high levels of antioxidative enzyme activities were determined in the tolerant genotypes of tomatoes, eggplant, peppers, cucumbers, melons, squash, beans, okra, etc. to several abiotic stress factors. Both the whole plant and in vitro callus culture experiments gave similar results. Antioxidant enzymes can be useful for screening to determine the tolerant and sensitive plant genotypes against abiotic stresses

The effect of different organic matters on plant growth regulation and nutritional components under salt stress in sweet sorghum [Sorghum bicolor (L.) Moench.]

Salinity is one of the major constraints of crop production, especially in the world's arid and semi-arid regions. Variations in the nutritional components of Gulseker sweet sorghum (local variety) and the effects of different organic matter on morphological and physiological changes under salt stress were examined herein. The response of sweet sorghum to applications of different organic matter [amino acid (AA), cow/farmyard manure (CM), biochar (BC), humic acid (HA), sheep manure (SM), worm casting (WC), poultry manure (PM), and bat guano (BG)], as well as water irrigation salinity at 150 mM NaCl were evaluated under greenhouse conditions using plastic pots containing 11 L of peat:perlite (2:1). Plants grown under different treatments were then classified as morphological (shoot fresh and dry weights, shoot diameter, shoot length, number of leaves and leaf area per plant) and physiological parameters (relative water content (RWC), chlorophyll (SPAD), malondialdehyde (MDA), Na+, K+, Ca++, and Cl- ion content. The results revealed that salt stress caused reduced growth parameters and chlorophyll, RWC, K+ and Ca++ ion content, while MDA content, Na+ and Cl- accumulation showed an increase. The results showed that the organic matter treatments diminished the damaging effects caused by salt stress via a reduction in the uptake of Cl- and Na+, which enhanced K+ and Ca++ uptake and reduced the MDA levels, presenting a favorable effect in reducing the oxidative stress that emerged from salt stress

Screening of Tomatoes for Their Resistance to Salinity and Drought Stress

In the study, 55 tomato genotypes have been investigated for their responses against salinity stresses in 48 day old early plant growth stage. For these purposes, several morphological and physiological measurements and analysis have been done in stressed plants. Shoot and root dry weights, plant height, leaf number, leaf area, relative water content, stomatal conductance, leaf osmotic potential, leaf water potential, shoot K, Ca and Cl concentrations were measured and analyzed. Salt and drought tolerant and sensitive (intolerant) genotypes have been found out according to the responses of the tomato genotypes to the above mentioned morphological and physiological parameters. At the end of the study, the fifty-five tomato genotypes were classified as tolerant, mildly tolerant or susceptible. Shoot dry weight, plant total leaf area, leaf water potential, leaf osmotic potential, stomatal conductance, K, Ca, Na and Cl concentrations in shoot and root, K/Na, Ca/Na, membrane injury index and visual appearance of damages were more relevant parameter for screening studies. Keywords: Stress, saline, water, tolerance, selection, breedin

Responses of Some Melon (Cucumis sp.) Genotypes to Salt Stress

WOS: 000261499500012The aim of this research is to identify differences in salt tolerance of melon genotypes and the possibility of using plant biomass values and degree of ion accumulation of leaves to determine salt tolerance. In addition, the increase in MDA amount of leaves on salt stress was evaluated. 36 different genotypes were identified according to different parameters in respect to salt tolerance and susceptibility to salinity, correlation coefficients among these characters were determined, It was observed that salt damage in melons is probably the result of toxic effects of Na+ and Cl- ions and the genotypes having low amounts of these ions are more tolerant. Midyat, Besni and Semame varieties were determinad as salt tolerant melon genotypes; Ananas and Yuva melon cultivars were most sensitive to salt stress

Physiological responses of the M-1 sainfoin (Onobrychis viciifolia Scop) plants to gamma radiation

WOS: 000390736100012PubMed ID: 27619947Effects of gamma radiation on physiological responses of the M-1 sainfoin plants were investigated. Seeds of sainfoin ecotype 'Kocas' were exposed to 0, 400, 500 and 600 Gy from a Co-60 source at a dose rate of 0.483 kGy h(-1). Irradiated and unirradiated seeds were sown into culture vessels containing MS-basal medium to be cultured for 30 days under in vitro conditions. At the end of this period, seedlings, which germinated from the radiated and unirradiated seeds, were transferred into pots in a growth chamber for 30 days more. Chlorophyll contents, activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR), as well as contents of monodehydroascorbate reductase (MDA) and proline were examined in unirradiated and irradiated 60-day-old seedlings. Overall, the activities of the antioxidant enzymes (SOD, CAT and GR) and contents of chlorophyll and proline in the leaves tended to increase after irradiation in a dose dependent manner. By contrast, the activity of APX decreased. The lipid peroxidation characterized by the MDA content remained unchanged, except after irradiation to 500 Gy. The highest CAT activity and the highest praline content were observed after irradiation to the highest dose of 600 Gy. The highest SOD and GR activities were observed after irradiation to the lowest tested dose of 400 Gy. This is the first study that provided basic information on the impact of gamma radiation on physiological responses of sainfoin and its radiosensitivity. These findings will be useful in development of a mutation breeding program of sainfoin

Comparison of Physiological Parameters for Drought in Tomatoes Between Early Stage in Pot and Mature Stage in Field

4th International Conference on Agriculture and Horticulture (AGRI) -- FEB 15-17, 2015 -- Amsterdam, NETHERLANDSWOS: 000380953000072Forty-five days old tomato plants grown in pot and 122 days old tomato plants grown in field were compared for drought responses. The relationships between young and mature plants responses will be useful to shorten the drought breeding process and it will not be necessary to grow the melon plants until the mature stage. Therefore time, labor and money can be saved in the drought breeding programs. Twenty-four different tomato genotypes were used for the pot and field experiments. The stomatal conductance, membrane injury, leaf water potential, leaf osmotic potential, leaf temperature, leaf Ca and K concentrations, shoot fresh weight and the visual shoot appearance by the 1-5 scale evaluation were investigated. The degree of the drought stress was 50 % irrigation of the control plants. The main results of the tomato research were: 1) The data relative to control showed definitely higher relationships than the data in absolute under the drought, 2) The most important relationships between young and mature tomato plants that can be used to shorten screening/breeding process were stomatal conductance (r = 0.608), leaf calcium (Ca) concentration (r = 0.573), membrane injury index (r = 0.510), leaf water potential (r = 0.499), shoot fresh weight (r = 0.477), shoot damage visual scale appearance (r = 0.314) and the leaf potassium concentration (r = 0.2043), respectively. (C) 2015 The Authors. Published by Elsevier B.V

The Physiological Parameters to Compare for Drought Between Early Stage In Pot and Mature Stage In Field for Melons

4th International Conference on Agriculture and Horticulture (AGRI) -- FEB 15-17, 2015 -- Amsterdam, NETHERLANDSWOS: 000380953000148Melon research was carried out in order to investigate the relationships of drought responses between young and mature plants. These relationships will be useful to shorten the drought breeding process and it will not be necessary to grow the melon plant until the mature stage. Therefore time, labor and money can be saved in the drought breeding programs. Twenty-nine days old plants grown in pot and 113 days old plants grown in field under the drought stress were compared for some physiological parameters. The number of melon genotypes was 29 for both the pot and field experiments. The parameters investigated were stomatal conductance, membrane injury, leaf water potential, leaf osmotic potential, leaf temperature, leaf Ca and K concentrations. The main results of the melon research were: 1) The data relative to control showed definitely higher relationships than the data in absolute under the drought, 2) The most important relationships between young and mature tomato plants that can be used to shorten screening/breeding process were stomatal conductance, leaf temperature, leaf osmotic potential, membrane injury, and leaf Ca concentration, respectively. (C) 2015 The Authors. Published by Elsevier B.V