F. Mohamed

In vitro cloning of two cumin landrace lines via shoot-tip culture

Summary Shoot-tip explants were excised from axenic and non-axenic plant cultures of two cumin (Cuminum cyminum L.) landrace lines from Assiut (ASS) and Qina (QIN), Egypt. Explants were cultured on MS (Murashige and Skoog, 1962) medium supplemented with different concentrations of benzyladenine (BA) or kinetin. The two landraces performed similarly throughout the study. Shoot-tip explants from axenic cultures were superior to those prepared from non-axenically grown plants regarding the percentage of explants that produced micro-shoots and the number of micro-shoots that proliferated. The maximum number of excisable micro-shoots was produced on medium with 1 µM BA. Up to 20 micro-shoots per explant were excised from cultures on this medium. The largest number of micro-shoots obtained on medium containing kinetin was five. Most (80–90%) micro-shoots formed roots on medium with 1 µM indole-3-butyric acid (IBA) and 2% (w/v) polyethylene glycol (PEG-6000). The survival rate ex vitro was as high as 70%. A high concentration of BA (4 µM) induced calli, retarded elongation of the micro-shoots and reduced both the number of roots formed on subsequent rooting medium, and plant survival ex vitro. This study supports the feasibility of in vitro cloning of cumin using shoot tips for germplasm collection, conservation and exchange.

Rooting of bean leaves and use in germplasm evaluation for common bacterial blight resistance

SummaryA simple protocol for leaf rooting in beans (Phaseolus vulgaris L.) was developed and used to investigate the reaction of Xanthomonas campestris pv. phaseoli (Xcp), causal pathogen of common bacterial blight disease, in detached versus attached bean leaves. Trifoliate leaves of different sizes (one-third, two-thirds, and fully expanded), either with or without the pulvinus attached to the petioles, were excised from 20 day-old plants of six bean cultivars/lines. Leaf cuttings were cultured in potting medium and then incubated for 5 to 10 days under transparent polyethylene plastic cover in the greenhouse. Roots were readily initiated along the petioles of the leaf cuttings, whether the pulvinus was present or absent. All leaves which were two-thirds expanded and fully expanded developed roots 5 to 7 days after culture. Eighty to 90 percent of the leaves which were one-third expanded formed roots 8 to 10 days after incubation. Laminae of the rooted leaf cuttings were viable and green during the 2 to 3 months period in culture after removing the plastic cover. The common bacterial blight reactions were similar for inoculated attached leaves, detached rooted leaves (inoculated either after or prior to rooting), and moistened detached leaves incubated without rooting. The latter were only usable for evaluation of the Xcp reaction in growth chamber experiments but not under greenhouse conditions. The rooted leaves would be useful for screening bean lines for multiple disease resistance, especially if the pathogens require different environments for disease expression.

Characteristics and inheritance of natural facultative-parthenocarpic fruit-set in 'Nadja' tomato under low temperature conditions

Abstract‘Nadja’ tomato (Lycopersicon esculentum Mill.) set both seedless and seeded fruits under the fluctuating temperatures prevailing during late-March and early-April in Assiut district, Egypt. Entirely seedless fruits developed under the low temperatures prevailing during Dec. Seedless fruits seemed to develop vegetatively , i.e. with no need for stimulus pollination. All seedless fruits were normally jelled and appeared similar in shape and size to the seeded fruits. Study of F1, F2, and backcross generations for the crosses ‘Cal Ace’ × ‘Nadja’ and ‘Peto-86’ × ‘Nadja’ suggested that the expression of the trait was due to single homozygous recessive gene. Yield produced by ‘Nadja’ was higher than the F1, F2, and backcross generations in both the early- summer and the late-winter plantings. Potentially useful parthenocarpic segregates were found in F2 of the two crosses for increased fruit weight of normally shaped and jelled fruits.

Assessment of cognitive function in patients with myasthenia gravis

Aim: During the past decade, there has been an increasing interest in the evaluation of cognitive function in myasthenia gravis (MG), neuromuscular transmission disorder caused by acetylcholine receptor auto-antibodies. However, the results of previous studies on cognition and MG are inconsistent and controversial. This study aimed to evaluate cognition in patients with mild/moderate grades of MG. Methods: This study included 20 patients with MG with a mean age of 28.45 ± 8.89 years and duration of illness of 3.52 ± 1.15 years. Cognition was tested using a sensitive battery of psychometric testing (Mini-mental State Examination [MMSE], Stanford-Binet Intelligence Scale 4 th edition [SBIS] and Wechsler Memory Scale-Revised [WMS-R]) and by recording P300 component of event-related potentials (ERPs), a neurophysiological analog for cognitive function. Results: Compared with healthy subjects (n = 20), patients had lower total scores of cognitive testing (MMSE, SBIS and WMS-R) (P = 0.001), higher Beck Depression Inventory 2 nd edition scores (P = 0.0001) and prolonged latencies (P = 0.01) and reduced amplitudes (P = 0.001) of P300 component of ERPs. Correlations were identified between total scores of cognitive testing and age (r = -0.470, P = 0.010), duration of illness (r = -0.788, P = 0.001) and depression scores (r = -0.323, P = 0.045). Using linear regression analysis and after controlling for age and depression scores, a significant correlation was identified between total scores of cognitive testing and duration of illness (β = -0.305, P = 0.045). Conclusion: Patients with mild/moderate MG may have cognitive dysfunction. This is important to determine prognosis and managing patients.

Breeding for Drought Resistance in Common Bean: In Vitro Assay for Root Osmotic Potential

ABSTRACT Initial and adjusted osmotic potentials of separate leaf- and root-derived calli were assessed in vitro for two teparies (Phaseolus acutifolius A. Czray) and a common bean (P. vulgaris L.) cultivar differing in physiological and morpho-physiological reactions of intact plants to water stress. Unstressed leaf- and root-derived calli of common bean (CB) had higher preexisting osmotic potential (ψs) and relative growth rate (RGR) but lower dry-matter percent (DM) than those of tepary bean (TB) lines when grown on basal Murashige and Skoog medium (–0.30 MPa). Exposure to water stress (−0.58 MPa) imposed by adding polyethylene glycol (10% [w/v], PEG-10,000) did not affect these parameters for leaf-derived callus of CB and both leaf- and root-derived calli of TB. However, root-derived callus of CB showed decreased ψs that was maintained after transferring stressed callus onto medium lacking PEG for recovery from water stress. Nevertheless, its RGR decreased and DM increased. Stressed plants of both CB and TB grown in the greenhouse manifested significant reduction in leaf, stem, and root dry mass and leaf area. However, the magnitude of mass reduction was especially high for CB stem, leaf, and root. While TB root system penetrated deeper in the soil profile, CB root depth did not significantly change in response to drought. In addition, substantial CB root mass was detected in the top 10 to 20 cm of the soil profile. Stomata conductance and transpiration rate were higher for CB than TB under both well-watered and water-stress conditions. Significant relative water content reduction was detected only in CB. In spite of water stress, soil moisture was high around roots of CB compared with TB, suggesting lesser efficiency of CB root system to extract water. Stressed CB grown in the production field did not produce seed yield whereas TB gave 60 to 64% of its potential dry seed yield. In vitro assay for root osmotic potential should be useful in improving drought resistance in common bean.