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  • Author or Editor: M. M. El-Araby x
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Heavy metals (Cu, Fe, Mn, Pb and Zn) were estimated in water, soil sediments and shoots of the predominant wild plants at certain locations of main drains in Giza (El-Moheet, El-Lebeny, Nahea and Kafr Hakeem) and Cairo (El-Massara sites 1, 2, 3). Heavy metal concentrations were higher in soil than in water, where these contents in either of them were not crossing the threshold of permissible levels, with the exception of Fe which showed substantial concentrations in water and soil sediments, especially at certain drain sites. Heavy metal accumulation was evident in plant shoots at different sites. An interesting result was the potential accumulation of Fe in shoots of Cyperus spp. (C. alopecuroides, C. dives, C. rotundus), Eichhornia crassipes, Eremopoa persica and Phragmites australis to limits exceeding those in soil. Other plant species also showed high abilities to hyperaccumulate one or more of the elements under study at certain locations. Endogenous polyamines (PAs): putrescine (Put), spermidine (Spd), and spermine showed enhanced levels with increase of heavy metal contents in plant shoots. In this instance the highest positive correlation was shown by Spd followed by Put. Correlation coefficients for total heavy metal contents and total PAs showed tight positive relation. This rule was obvious but not always consistent with respect to the correlation between the contents of total heavy metals and glutathione (GSH) or the lipid peroxidation product malon-di-aldehyde (MDA). Recovery of Eichhornia crassipes plants collected from El-Moheet, El-Lebeny, and El-Massara (3) drain sites, showed decreases in the levels of GSH and MDA after 6 days in a pool of renewal fresh water, whereby inconsistent changes were recorded after 12 days.

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Seeds of tomato (Lycopersicon esculentum Mill., variety Castle rock) were osmoprimed in polyethylene glycol 6000 (PEG; 20%) or K2HPO4 (200 mM) solution for 8 hours, 3 days or 7 days, while another group of seeds were left in water for the same periods. The GA3/ABA ratio was the most important hormone factor, which promoted germination in seeds soaked in H2O and led to improved germination performance. This ratio showed slight variations between hydroprimed and osmoprimed seeds after 8 hours, but afterwards, from 3 to 7 days, it was gradually increased in the osmoprimed seeds and was substantially elevated in seeds germinating in H2O. Changes in the concentrations of phenolic compounds suggested their possible role in germination silencing in the osmoprimed seeds, but at relatively low concentrations. Protein patterns showed no marked variations in hydroprimed and osmoprimed seeds after 8 hours, but different types were observed, particularly after 7 days. A comparison of the protein banding patterns of seeds after 1 day and 7 days in the osmoconditioning solutions (PEG or K2HPO4), H2O, GA3 or ABA showed certain treatment-specific protein bands, particularly in PEG and ABA solutions. Longitudinal sections of seeds (after 3 days) showed lysis of the micropylar endosperm and radicle protrusion in H2O or GA3, whereas in PEG or K2HPO4 solution the radicle expanded inside the seed and the micropylar endosperm was completely intact. In ABA solution, the whole endosperm was compact and the seed became extensively desiccated.

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