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Phosphorus Dynamics in Wheat Rhizosphere vis-a-vis P nutrition under Elevated Atmospheric Carbon Dioxide and Temperature

KrishiKosh

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Title Phosphorus Dynamics in Wheat Rhizosphere vis-a-vis P nutrition under Elevated Atmospheric Carbon Dioxide and Temperature
Ph D
 
Creator Manoj Kumar
 
Contributor Anand Swarup
 
Subject tillage, crops, yields, fractionation, fertilizers, wheats, economic resources, zero tillage, grain, land resources
 
Description T-8309
ABSTRACT
ising concentration of atmospheric CO2 is expected to increase the growth,
yield and hence the nutrient requirements of C3 crops like wheat. In order to test the
hypothesis whether elevated CO2-induced increase in crop P demand elicits certain
morphological, physiological and biochemical adaptation/compensatory responses by
plants to meet the higher P demand, a controlled environment growth experiment was
conducted in National Phytotron Facility, IARI, New Delhi, where wheat as a test crop
was grown under two levels of atmospheric CO2: ambient (385 μmol mol-1) and elevated
(650 μmol mol-1); two levels of atmospheric temperature: ambient (ambient air
temperature of rabi season in India) and elevated (ambient+3°C); and three levels of P
fertilization: zero (control), 100% and 200% of recommended P dose to wheat. Grain
yield and biomass partitioning, plant P demand, nutritional qualities of wheat grains,
fertilizer P use efficiency, P uptake and utilization efficiencies, dynamics of various P
fractions, and the activities of phosphatase enzymes and organic acids in rhizosphere of
wheat were analyzed at CRI, anthesis and maturity stages of plant growth.
Despite the growth stimulatory effects of elevated CO2 which, to a certain
extent, compensated the growth and yield reductions caused by elevated temperature, the
combined elevation in atmospheric CO2 and temperature resulted in an overall decline of
17% and 13% in yield and harvest index of wheat respectively. As a result of the
interactions between atmospheric CO2 and temperature, grain protein, Zn and Fe
concentrations were reduced by 9%, 24% and 20% respectively under concurrently
elevated CO2 and temperature. Changes in the concentration and composition of certain
protein polypeptides and high molecular weight glutenin subunits indicated at the
deterioration of protein quality while the huge increases in phytic acid: Zn and phytic
acid: Fe molar ratios suggested the drastic decline in bioavailability of Zn and Fe in
wheat grains under elevated- CO2 and temperature. Higher doses of P fertilization
helped in reducing the yield loss caused by combined elevation of CO2 and temperature,
but caused further deterioration in nutritional quality of wheat, suggesting a definite
trade-off between yield and nutritional quality of wheat under changing climate. Total P
uptake by wheat was increased by 58% under singly elevated atmospheric CO2 while
17.4% increase was observed under combined elevation of CO2 and temperature. P
requirement of the plants grown under ambient CO2 was satisfied at 100% P level as
asserted by no further increase in P uptake at 200% P application. By contrast, P uptake
under elevated CO2 continued to increase significantly even up to 200% P application,
suggesting higher P demand by plants grown under elevated CO2 and temperature.
 
Date 2016-10-21T13:59:12Z
2016-10-21T13:59:12Z
2010
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/81254
 
Format application/pdf
 
Publisher IARI,Division of Soil Science and Agricultural Chemistry