L. Shekari; M. M. Kamelmanesh; M. Mozafarian; F. Sadeghi
Abstract
Introduction: Aluminum (Al), cobalt (Co), sodium (Na), selenium (Se), and silicon (Si) are considered as beneficial elements for plants. They are not required for all plants but they can improve the growth and development of some plant species. Selenium is an essential element for human with antioxidant ...
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Introduction: Aluminum (Al), cobalt (Co), sodium (Na), selenium (Se), and silicon (Si) are considered as beneficial elements for plants. They are not required for all plants but they can improve the growth and development of some plant species. Selenium is an essential element for human with antioxidant and antivirus functions but is not considered essential for higher plants. Selenium is reported to be protective against cancer and more than 40 types of diseases are associated with Se deficiency. The amounts of selenium in food also depend on the amount of the element in the soil. However, its beneficial role in improving plant growth and stress tolerances is well established. Plants revealed different physiological reactions into the Se levels, some specious accumulate it unlike some which are sensitive and Se is a toxic element for them. Some studies showed that Se can reduce adverse effects of salinity, drought, high and low temperatures and also heavy metal stress by enhancing antioxidant defense and MG detoxification systems. Pepper is one of the most important vegetable crops which have strong antioxidant properties. The effect of Se on vegetable especially on hot pepper is not well documented.
Materials and Methods: Present experiment was designed in order to study the effects of different concentrations of selenium on vegetative growth and physiological trait of hot pepper (Capsicum annum cv. kenya) in hydroponic conditions in the greenhouse at the Department of Horticulture Science, Islamic Azad University of Shiraz (Iran) under natural light with a day/night average temperature of 25/17 °C, relative humidity of 50±8.5% and photoperiod 14/10 (day/night). This experiment was carried out based on completed randomized design (CRD) with 5 Se levels at (0 as control, 3, 5, 7 and 10 µM) with 3 replications. 30 days old seedling with uniform size were selected and transplanted into 4 L pot containing a mixture of peat moss and perlite (1:1). The nutrient solution was a modified Hoagland’s solution and each plant received 400 mL nutrient daily. Selenium concentrations were added by 0, 3, 7 µM Na2SeO3 (Merck, Germany) 10 days after transplanting. Leaf number (by counting), leaf area (with leaf area meter), relative water content (RWC), membrane stability index (MSI), chlorophyll and carotenoids content were determined one month after treatment applications. All data were subjected to one-way ANOVA by Statistix 8 (Tallahassee FL, USA) and the means were compared for significance by the least significant difference (LSD) test at p < 0.05.
Results and Discussion: The results showed that selenium supplement at 5 µM significantly increased relative water content by 12.8% compared to control. Se increased root growth and thus absorbed more water and increased RWC in present experiment. Selenium at 7 and 10 µM Se increased membrane stability index by 33.61 and 80.06, respectively, compared to control which may be due to increasing potassium by Se application. Selenium at 3 and 5 µM increased leaf area by 24.6% and 25.1% relation to plants which were grown without Se supplementation. Leaf number increased by application of 5 µM Se about 15.14% and chlorophyll a, b and total increased by 64.67%, 38.5% and, 55.8%, respectively, in comparison with plants grown without Se application. Carotenoid content was not affected by different Se concentrations. Se increase chlorophyll content by increasing Mg and Fe absorption, or protect of chlorophyll content against chloroplast enzymes. The highest leaf area was observed at 3 µM Se in comparison with other treatments. Se at 5 µM is beneficial for growth, photosynthesis pigments, and leaf area and leaf number. Se application had no beneficial influence on lateral shoot. The highest starch concentration was observed at 5 µM Se in comparison with other treatments and control (by about 60% in comparison with plants were grown without Se application).
Conclusion: In general, the result of present study indicated that selenium at low concentrations improved plant growth (such as leaf area and leaf number), physiological trait (relative water content and membrane stability index) and photosynthesis pigments (chlorophyll a and b) of hot pepper in hydroponic conditions. Also, it is suggested that this experiment should be repeated on some other important vegetable during growth and reproductive stages in hydroponic and soil condition and also on hot pepper quality and quantity of fruit.
maryam haghighi; maryam mozafariyan
Abstract
Decreasing irrigation via partial root zoon drying (PRD) save water and decreased production expenses. For comparing common irrigation and PRD on tomato cv. Falcato an experiment was designed in Massey University of New Zealand. Treatments were control (irrigation in a Field capacity in each irrigation ...
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Decreasing irrigation via partial root zoon drying (PRD) save water and decreased production expenses. For comparing common irrigation and PRD on tomato cv. Falcato an experiment was designed in Massey University of New Zealand. Treatments were control (irrigation in a Field capacity in each irrigation to whole root zoon) and PRD (irrigation in a half of Field capacity in each irrigation to one side of root zoon). The results were shown that superoxide dismutase and peroxidase activity increased in PRD compare with control. Photosynthesis, mesophyll conductance, photosynthesis water efficiency, fresh and dry weight of root and shoot decreased in PRD. NACE (Nutrient Acquisition Efficiency) of leaf was the highest for Zn and Na and the lowest for P when PRD applied compare with control. Yield indices like MP increased significantly by 63% compare to first harvest. YSI (Yield Stability Index) increased by 46% in third harvest compare with second one. The TOL (Tolerance index) increased by 80% in last harvest compare with first one. GMP (Geometric Mean Productivity) in the second harvest increased by 62% compare to first one.
M. Haghighi; M. Mozafariyan; Z. Afifipour
Abstract
The superabsorbent polymer withholding water and disperse it gradually to roots increase soil water capacity. To study the effect of superabsorbent polymer on decreasing water stress effect as well as increasing irrigation efficiency a factorial experiment based on randomized block design with 4 replicates ...
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The superabsorbent polymer withholding water and disperse it gradually to roots increase soil water capacity. To study the effect of superabsorbent polymer on decreasing water stress effect as well as increasing irrigation efficiency a factorial experiment based on randomized block design with 4 replicates was design. Treatments were 0, 10 and 20 % V superabsorbent and irrigation levels 25, 50 and 100% field capacity in greenhouse of Shiraz University. The results were shown that drought stress decreased chlorophyll content, fresh and dry weight but did not effect on fruit parameters at 5%. Superabsorbent improved tomato growth in stress condition and in 50% FC,10% superabsorbent increased relative water content to 14%and fresh weight of root to 60%. Chlorophyll content increased to 22% in 25%FC with 20% superabsorbent relative water content and root fresh weight increased 28 and 53% respectively. In 25%FC with 20% superabsorbent. Superabsorbent elevated hazardous effect of drought stress and with holding the water in root zoon cues normal plant growth.
