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  • Author or Editor: A. A. Hassanein x
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The effect of water stress on the germination, seedling growth, organic solutes, peroxidase pattern and peroxidase activity of different Vicia faba lines was studied. Studies on germination in polyethylene glycol and in soil indicated that lines such as Line 2/4 which were able to germinate under water stress caused by high concentrations of polyethylene glycol, were also able to germinate and grow in soil with a low water content. While the fresh and dry masses of all the lines were markedly decreased as the water stress level increased, Line 2/4 exhibited higher dry matter than the other lines tested. Pigment contents were more or less unchanged in some lines (102, 159 and 2/4) but increased in others (67 and 103) as the stress level increased. In general, the soluble sugar, soluble protein, free amino acid and proline contents in the shoots and roots of all the tested lines progressively increased as the stress level increased. These values were higher in the plant shoots than in the roots except for Line 2/4, which was the only one that could be grown at 30 % field capacity, and which accumulated soluble sugars and free amino acids in the roots rather than in the shoots Differences in the peroxidase (POX) pattern were found among the roots and shoots of the tested lines. Under drought stress, the number and staining intensity of the POX bands as well as the POX activity were lower in the shoots than in the corresponding unstressed control plants, especially in the sensitive line (159). In the plant roots, while the number of peroxidase isoenzymes and peroxidase activity were reduced in the sensitive line, they were unaffected in the resistant line (2/4).

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A procedure for the separation of 64,67Cu radioisotopes from irradiated natural zinc targets was developed. Production of 64,67Cu was carried out using 64,67Zn(n,p)64,67Cu reactions by fast neutron bombardment of natural zinc targets at The Second Egyptian Research Reactor (ETRR-2). The sorption behavior of 65Zn and 64,67Cu ions in HCl acid solutions showed high affinity of Cu ions towards 6-tungstocerate(IV) gel matrix compared with Zn ions. Carrier-free 64,67Cu radionuclides were separated from 65Zn on 6-tungstocerate(IV) column matrix by eluting the column with 10 ml 0.001 and 1M HCl acid solutions. The separated 64,67Cu radionuclides were of high chemical, radiochemical and radionuclidic purity.

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A gradual increase in NaCl concentration in the growth medium was used as a strategy to adapt sorghum plants (Sorghum bicolor L.) to relatively high concentrations of NaCl. over a period of 15 days, a low percentage (22.2%) of sorghum seeds germinated in 200 mM NaCl, but most of the seedlings obtained (85.8%) died. On the other hand, plants subjected to adaptation by a gradual increase in NaCl concentration in the growth medium became capable of growth in soil containing 300 mM NaCl. In general, salinization induced a highly significant decrease in fresh and dry masses, and in the pigment content of sorghum seedlings. The content of free amino acids and soluble carbohydrates increased with a rise in the salinization level, especially in the adapted sorghum plants. The adapted plants contained less Na+ but more K+ compared to the unadapted plants, especially when the plants were subjected to relatively high NaCl concentration. Plants adapted in soil showed a new peroxidase isoenzyme form (POX-4). The peroxidase band POX-1 was detected under salt stress in both adapted and unadapted plants. Under salt stress, indophenol oxidase and glutamate oxaloacetate transaminase expressed new isoenzyme forms, IPOX-3 and IPOX-5, and GOT-2 and GOT-3, respectively. The induction of salt tolerance by a gradual increase in NaCl concentration for three weeks was recommended to overcome the inhibition of seed germination in saline soil.

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Crude extracts of wild plant species were investigated for their activity against cotton aphid, Aphis gossypii Glov. Extracts were obtained by extracting fresh plants successively with solvents of variable polarities, hexane, diethyl ether, ethyl acetate, acetone and ethanol.  Among of 125 solvent extracts, hexane, diethyl ether, and ethyl acetate extracts of Hyoscyamus muticus, acetone extract of Verbascum sinuatum and ethanol extract of Rumex dentatus gave high toxicity against A. gossypii. Their LC50 values were 0.727, 0.883, 1.013, 0.805 and 1.143 mg/cm2, respectively.  Results indicated that 19 plant hexane extracts induced high toxic effect (LC50 ranged between 0.727 and 7.481 mg/cm2) against A. gossypii. Also, 22 plant diethyl ether extracts showed high toxic effect towards the tested insect (LC50's ranged from 0.883 to 10.00 mg/cm2). On basis of the LC50 value, 21 plant ethyl acetate extracts exhibited potent activity to A. gossypii (LC50 values ranged between 1.013 and 10.857 mg/cm2). Twenty-two acetone extracts that revealed high toxic effect (LC50 values ranged from 0.805 to 9.377 mg/cm2) to the tested pest, also 24 tested plant ethanol extracts that exhibited potent activity to A. gossypii (LC50 values ranged between 1.143 and 8.727 mg/cm2).  The ethanol plant extracts proved superior efficiency against A. gossypii followed by acetone, hexane, ethyl acetate and finally diethyl ether plant extracts.

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