fire blight, caused by the bacterium erwinia amylovora, is one of the most destructive diseases of plants in the rosaceae subfamily pomoideae. the objective of this study was to determine the level of resistance of 30 pear cultivars and describe the biochemical changes induced in some resistant and susceptible cultivars. the level of resistance was determined by the length of the fire blight le...

To assess nickel-induced toxicity in plants, Zea mays seeds were germinated and cultured on nutrient solution with nickel concentrations of 50-200 μM for a period of two weeks. Observed biological makers included biomass, soluble and total protein contents, and the activities of guaiacol peroxidase (GPX), ascorbate peroxidase (APX), catalase (CAT), and phenylalanine ammonia-lyase (PAL) in the l...

The involvement of the ascorbate (AsA) system in the response of pumpkin (Cucurbita pepo L.) roots to aluminium stress was studied. The treatment of 5-day-old pumpkin seedlings with 50 microM aluminium sulphate resulted in approximately 60% inhibition of root growth within 48-60 h of treatment, while aluminium accumulated in the roots reaching a maximum within 48h. During the same period, the h...

This study investigated oxidative stress and the antioxidant response to boron (B) of chickpea cultivars differing in their tolerance to drought. Three-week-old chickpea seedlings were subjected to 0.05 (control), 1.6 or 6.4 mm B in the form of boric acid (H(3)BO(3)) for 7 days. At the end of the treatment period, shoot length, dry weight, chlorophyll fluorescence, B concentration, malondialdeh...

Oxygen activation in all heme enzymes requires the formation of high oxidation states iron, usually referred to as ferryl heme. There are two known intermediates: Compound I and II. The nature heme—and whether it is an FeIV=O or FeIV-OH species—is important for controlling reactivity across groups enzymes. most recent evidence indicates that unprotonated species. For II, not unambiguously estab...

The natural resistance against the majority of potential pathogens that exist in most plant species is known as non-host resistance. Several reports suggest the role of antioxidant enzymes in non-host resistance. We assayed the expression or activity of four scavenging enzymes during non-host pathogen-plant interaction (Xanthomonas hortorum pv. pelargonii/mung bean) and host pathogen-plant inte...

In an effort to determine the biochemical markers for identifying genotypes before sowing for drought tolerance, changes in activities of antioxidant enzymes were determined in the seedlings of five drought-tolerant and five drought-sensitive wheat (Triticum aestivum L.) genotypes, each with different genetic background growing under normal and water deficit conditions induced by 6% mannitol. I...

Effect of drought stress induced by mannitol on secondary products in callus Golden Sunrise cherry tomatoes were studied vitro. Seeds irradiated with gamma at the doses (0, 20, or 40 Gy), and germinated Murashige Skoog, (MS) basal medium. Callus initiated from cotyledon leaf explants using a combination (2.0 kin + 2.0 IAA mg. l-1) then transferred into MS medium supplemented concentrations 40, ...

The effects of exogenous abscisic acid (ABA) and its two agonists, Sulfacetamide (Sa) and Sulfasalazine (SS) on tolerance of tomato (Lycopersicon esculentum Mill. Cv. Super chief) under drought stress were studied. Eight-week plants were treated with ABA (25 and 50 mg/L), Sulfacetamide (Sa) (25, 50 and 100 mg/L) and Sulfasalazine (SS) (25, 50 and 100 mg/L). Solutions were sprayed daily and samp...