تاثير المولبيدنيم في النظام الدفاعي لنبات الماش تحت الاجهاد المائي

Abstract

In order to study the effect of Molybdenum (Mo) on defense system of mung bean (local cultivar) under water stress, a field experiment was conducted during the fall season of 2018 in loamy soil in Al-Buthiab region in Ramadi. The experiment included 4 Mo concentrations (0, 15, 30, 45 mg L-1) and three irrigation intervals (irrigation each 4, 8 and 12 days). A split plot arrangement was used according to RCBD, where the irrigation intervals occupied the main plots while the Mo concentrations laid in subplots. The important results of this study were summarized as follow: 1- The application of Mo had a significant on some growth and yield traits and most biochemical traits. The concentration 45 mg L-1 achieved the highest mean of leaf area, pod length which were 1435.34 cm2 and 6.01 cm respectively as well as the highest mean of proline, CAT, POD and SOD which gave 499.33, 28.95, 35.45 and 122.78 Unit mL-1 respectively while the concentration 30 mg L-1 gave the highest mean of number of pods per plant (45.28 pod plant-1) while the concentration 15 mg L-1 gave the highest mean of plant dry weight (239.89 g Plant-1). 2- The growth and production of mung bean have been significantly affected by diverging of irrigation intervals from 4 to 8 then to 12 days between each two irrigations. All growth and yield traits were decreased at 12 days interval in comparison with 4 and 8 days intervals respectively. As for yield traits were increased at 4 days intervals while decreased at 12 days intervals. The divergent irrigation intervals contributed in activation of defense system enzymatic and non-enzymatic in parallel with the increase in lipid peroxidation in plant cells (MDA) due to the water stress. The activity of anti-oxidant enzymes reached to 20.89, 31.22, 94.56 Unit mL-1 at irrigation each 4 days while increased to 33.18, 36.56 and 136.41 unit mL-1 at irrigation each 12 days for CAT, POD and SOD respectively. This increase is in consistency with the increase of lipid peroxidation in plasma membrane (MDA). The content of plant from MDA 22.27 Unit mL-1 at irrigation each 4 days while it was 27.84 Unit mL-1 at irrigation each 12 days. As for proline behaved the same as anti-oxidant enzymes which was 451.75 mg g-1 at irrigation 4 days and the content in leaves was also increased with the increase of irrigation intervals up to 492.00 and 483.38 mg g-1 at irrigation eat 8 and 12 days respectively. 3- The two way interaction between the study factors had a significant effect in most studied traits with the exception of number of branch per plant which had the highest mean when plant treated with 30 mg L-1 at 12 days irrigation interval (7.95 branch plant-1). The treatment with Mo (e.g. 45 mg L-1) at 4 days interval led to achieving the highest mean of growth traits while yield traits behaved the same with exemption of seed weight (g) where the highest mean (4.50g) was obtained when plants treated with 45 mg L-1 and irrigated each 8 days, while there was not significant interaction in number of seed per pod trait. There was cooperation between Mo and irrigation intervals in raising of the enzymatic and non-enzymatic defence system. The treatment of 45 mg L-1 and irrigation each 12 days was superior in giving the highest mean of the CAT and SOD activities (36.04 and 140.29 Unit mL-1 respectively), while the treatment of 30 mg L-1 and irrigation each 12 days was superior in the highest mean of POD activity (37.99 Unit mL-1)