| Pak. J. Bot., 42(2): 943-953, 2010. | Back to Contents | ||||
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Updated: 20-05-10 | ||||
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DIFFERENTIAL POTASSIUM INFLUX INFLUENCES GROWTH OF TWO COTTON VARIETIES IN HYDROPONICS
LIAQAT ALI1*, RAHMATULLAH1, TARIQ AZIZ2, M. ASHRAF, MUHAMMAD AAMER MAQSOOD1 AND SHAMSA KANWAL1
Abstract: Potassium uptake rate of two cotton (Gossypium hirsutum L.) varieties viz., NIBGE-2 and MNH-786 was investigated in nutrient solution culture having deficient K @ 0.3 mM and deficient K+ Na @ 0.3 +2.7 mM. Depletion of K from solution was monitored over a period of 24 h at regular time intervals after 0, 0.5, 1.0, 1.5, 2, 3, 4, 5, 6, 8, 10, 12 and 24 h to estimate K uptake kinetics of the roots i.e. maximum influx, Imax and the Michaelis-Menten constant, Km. NIBGE-2 had about 2-fold higher (2.0 mg g rdw-1 hr-1) Imax value for K uptake rate at deficient K+Na than that (1.207 mg g rdw-1 hr-1) for MNH-786. Higher, Michaelis-Menten constant, Km (12.82 ppm) for K uptake rate was observed in both cultivars NIBGE-2 and MNH-786 at deficient K+Na than that at deficient K. Main effects of treatments and varieties had significant (p< 0.05) effect on shoot dry matter, root dry matter, total dry matter and leaf area per plant. Maximum K influx in NIBGE-2 at deficient K and deficient K +Na was attributed to enhanced growth response as compared to that in MNH-786.
1Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, Pakistan 2Sub-Campus Depalpur, University of Agriculture, Faisalabad, Pakistan *Corresponding author: shafqat_l@yahoo.com |
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