Effects of Molybdenum application on nutrient uptake and yield of rice and Nitrogenase activity of Rhizobacteria
In tropical soils, the deficiency of Mo may be seen in the rice plants. Hence, elucidating the optimum levels of Mo in soil and plants will be helpful for understanding the plant growth. The current study was conducted to assess Mo status in soils and plants, and to determine the influences of Mo...
שמור ב:
| מחבר ראשי: | |
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| פורמט: | Thesis |
| שפה: | English |
| יצא לאור: |
2016
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| גישה מקוונת: | http://ethesis.upm.edu.my/id/eprint/12590/1/FP%202016%2047%20-%20T.pdf |
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| סיכום: | In tropical soils, the deficiency of Mo may be seen in the rice plants. Hence,
elucidating the optimum levels of Mo in soil and plants will be helpful for
understanding the plant growth. The current study was conducted to assess
Mo status in soils and plants, and to determine the influences of Mo on in
vitro nitrogenase activities of some plant growth promoting rihizobacteria
(PGPR). Five rice cultivars (MR219, HASHEMI, MR232, FAJRE and MR253)
and 4 levels of Mo (0, 0.01, 0.1, and 1.0 mg L−1) were used for the first
experiment. The highest Mo uptake in shoots (0.70 μg plant-1) and roots (0.66
μg plant-1) were seen in the MR232 at the highest level of Mo (1 mg L-1) in
solution culture. Iron rates in shoot decreased with increasing Mo levels in
solution culture and reached 39.93 μg plant-1 at the highest level of Mo. Also,
phosphorus uptake in all cultivars increased with enhancing Mo in medium
culture and reached highest (0.6 %) in cultivar MR232. In other experiment,
Mo combination (0, 0.01, 0.05, 0.1, 0.5, 1, 1.5, 2, 2.5 mg L-1) was applied to the
growth medium contained four nitrogen fixation bacteria (UPMB10,
UPMB12, Sb16 and R19). Nitrogenase activity enhanced with increasing Mo
levels in growth medium of all bacteria strains except Sb16. The strongest
correlation (r =0.78**, p˂0.01) was found between Mo and ethylene
production in UPB10, and the weakest one was seen in R19 (r =0.49*, p˂0.05).
The highest ethylene productions in UPMB10 (99.6 μmol mol-1 hour-1),
UPMB12 (87.2 μmol mol-1 hour-1) and R19 (80.1 μmol mol-1 hour-1) were seen
in treatments contained 2.5 ppm Mo. We collected eleven soil series from
two depths of Kedah and Kelantan paddy fields. Sequential extractions of
soil Mo fractions indicated that Kranji series contained highest plant
available amount of Mo (0.26 mg kg-1) in comparison with other seven series
of Kedah soils (surface layer), and highest medium plant available Mo (0.24mg kg-1) was seen in Rotan and Sedaka series of Kedah area (surface layer).
In upper layers of Kedah soil series, we could not detect any acid soluble Mo
(associated with calcium). In surface layers of Kelantan, highest amount of
plant available Mo (0.23 mg kg-1) was found in in Lating series but medium
plant available of Mo (0.15 mg kg-1) was obtained from Cempaka series. In
lower depths of Kedah, Guar series contained highest plant available mount
of Mo (0.28 mg kg-1) and medium plant available rate of Mo (0.35 mg kg-1)
was seen in Rotan series. In lower layers of Kelantan, Lating series contained
highest amount of plant available Mo (0.34 mg kg-1) and medium plant
available of Mo rate (0.07 mg kg-1) was only found in Batu Hitam series. We
found out that cation exchange capacity was positively correlated with total
amount of Mo in upper layers of Kedah soil series (r= 0.61; P ≤ 0.05), and no
statistically correlation was found between Mo contents and soil properties
in Kelantan soil series.
For the last experiment, we used foliar and soil application methods in order
to determine the optimum Mo rate at which highest rice grain is produced.
We found out that grain yield of rice was correlated with total shoot dry
weight and plant height with r value of 0.53* and 0.74* in treatments sprayed
with Mo. The greatest grain yield (21 g plant-1) was seen in treatment of 5
mg Mo kg-1 in soil, and treatment of 30 μg Mo L-1 supplied as foliar. |
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