الفهرس 
THE IMPACT OF WATER TREATMENT RESIDUALS NANOPARTICLES ON THE SALT STRESS RESPONSE OF ZEA MAYS L.Only 14 pages are availabe for public view
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Abstract
Salinity is a major abiotic factor that limit plant development and productivity world wide.Under salinity, multiple adverse injuries occur, which affect plant growth and development at the physiological and biochemical dimensions. Therefore, many trails and approaches have been attempted to reduce the well-known negative effects of salinity on plant growth and production.The objectives of this study were to characterize the physical and chemical properties of nanoscale water treatment residuals (nWTRs) and nanoscale mango peels (nMPs) , evaluate the impact of the Nano priming of mango peels on germination, and the effect of nWTRs application and salinity stress on physiological parameters such as, chlorophyll content, enzyme content such as catalase and peroxidase,nutrients concentration ,soluble protein , proline ,and sugar content in zea mays .l plants. To achieve these objectives, these experiments were conducted as follows:
Seed germination experiment: Corn seeds (Zea mays L) cv. Giza 168 were soaked in mango peels nanoparticles suspensions (1000 mgL-1) at 25°C for 24 h. The Nano-primed seeds were rinsed with distilled water as the first priming solution, 6.5 dSm-1saline water as a second priming solution and seeds were rinsed in distilled water alone without nMPs as a third priming solution. Eight seeds were placed on each Petri dish; there were three replicate dishes for each treatment, and then germinated on moist filter paper in Petri dishes at 25oC. Five concentrations of 0 (control), 2.5, 6.5, 9.5 and 12.5 dSm-1 sea water were applied to each treatment for 7 days. After 7 days, germination percentage and seedling growth were measured.
1- Increasing salinity levels significantly reduced germination percentage of all priming treatments. This reduction in germination percentage (%) was significantly lower for seeds primed in nMPs-Saline Water compared to ones primed in nMPs-Distilled Water and ones primed in Distilled water. The reduction in germination percentage occurred at high salinity levels was due to the harmful effect of salinity on physiological processes which are effective on seed germination
2- Increasing salt concentration reduced the radicle length, plumule length, seedling volume, seedling fresh weight, root dry weight and shoot dry weight, however priming in nMPs-saline water significantly increased the radicle length, plumule length, seedling volume, seedling fresh weight, root dry weight and shoot dry weight compared to seeds Primed in nMPs-distilled water and ones primed in distilled water.
3- Nano priming of corn seeds at different salinity levels significantly improved vigor index, especially at nMPs-saline water priming treatment exposed to salinity stress.
Greenhouse Experiment:
Uniform seeds of Zea Mays L cv. Giza168 were screened and sown in 96 bottom perforated, plastic pots containing sandy soil. Each pot received the same amounts of fertilizers were added to all treatments. After emergence of the first true leaves (15 days after germination), the number of plants per pot were adjusted to two and irrigated from above using tab water at 100% field capacity every 2 days. At 20 days after sowing, a half strength (0.5) Hoagland’s nutrient solution was given once a week. The salt treatments started 1 month after sowing using water of different quality (control, 4, 8, and 12dsm-1) and three levels of nWTRs (1000,3000and 6000mgl-1) were applied along with a control. To avoid osmotic shock, saline irrigation water was increased gradually by 2 dSm-1 every 2 days until the desired salinity is achieved. After 30days of salt treatment, the plants were harvested and the growth and biochemical attributes of all plants were measured .Each pot (2 plants) was
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considered as one replicate with three pots per treatment. The experimental design was randomized block.
1- Total biomass of maize plants was decreased with the increase of salinity levels. However, application of different concentrations of nWTRs was significantly increased total biomass at different salinity stress.
2- Total chlorophyll content and total soluble sugar were significantly affected by salinity levels, and priming treatment. In general, total chlorophyll content,total soluble sugar were significantly decreased with increasing salinity levels from 0.7 to 12 dSm-1 in plants derived from unprimed seeds. The lowest leaf chlorophyll content and sugar were observed at the concentration of 12 dSm-1. However, results of this study showed that plants derived from seeds primed in nMPs-saline water produced more chlorophyll, sugar content. By application of different concentrations of nWTRs was significantly increased total chlorophyll and total soluble sugar at different salinity stress.
3- The enzyme activities (catalase& peroxidase) were increased in shoot maize plants as a result of increasing salinity levels, but decreased with the increase of nWTRs concentrations.
4- It is clear that P and K contents were significantly increased in shoot by increasing salinity levels with or without priming at different nWTR levels.
In similar, N and soluble protein contents were significantly affected by salinity levels, and priming treatments where, it was decreased by increasing of salinity levels at priming and unpriming treatments. Application of nWTRs to the growth medium significantly increased N and soluble protein contents of maize plants.
5- In contrast, Na concentration &Na+/K+ ratio in maize plants were significantly increased with increasing salinity levels.However; application of different concentrations of nWTRs was significantly decreased Na concentration & Na+/K+ ratio at different salinity stress.
6- In similar to CAT and POD activity,proline content was significantly increased by salinity levels, and priming treatments.In general, increasing salinity levels significantly (p<0.01) increased proline content in corn shoot for both primed and unprimed plants.
7- The maize plants derived from seeds primed in saline solution and nMPs significantly increased the proline content of shoot in comparison with ones unprimed. So, addition of different concentration of nWTRs to the growth medium significantly decreased the shoot proline content.