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The influence of gibberellic acid and sulfur fertilization rate on growth and S-use efficiency of mustard (Brassica juncea)
N.A. Khan, M. Mobin and Samiullah
Plant and Soil
Vol. 270, No. 1/2 (March 2005), pp. 269-274
Published by: Springer
Stable URL: http://www.jstor.org/stable/24125113
Page Count: 6
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Earlier research has shown that exogenous gibberellic acid (GA3) application increases shoot growth, photosynthesis and soil nitrogen (N) utilisation in mustard (Brassica juncea L. Czern & Coss.). Mustard has a high sulfur (S) requirement. Its assimilatory pathway is well coordinated with N and dependent on photosynthesis. Thus, the higher photosynthate production and an efficient use of N with the use of GA3 could result in an increase in S-use efficiency of the crop. The research was, therefore, carried out to study the effects of 10 μM GA3 spray on specific leaf area, plant dry mass, leaf carbon dioxide exchange rate (CER), plant growth rate (PGR), relative growth rate (RGR), net assimilation rate (NAR) and S-use efficiency (SUE) of mustard treated with 0, 100 or 200 mg S kg-1 soil levels. Plants treated with 100 mg S kg-1 soil and receiving GA3 treatment showed increased specific leaf area and dry mass accumulation compared to the control. At 0 mg S kg-1 soil, N and S concentrations were reduced. They increased with increasing S supply. GA3 application significantly increased N and S concentrations further. A two-fold increase in SUE in GA3-treated plants at 100 mg S kg-1 soil was noted in comparison to the control. SUE was not increased under excess S conditions beyond 100 mg S kg-1 soil. The increase in SUE was through increase in the growth, CER and use efficiency of N by the crop due to GA3 application.
Plant and Soil © 2005 Springer