Foliar Applied Phosphorous Enhanced Growth, Chlorophyll Contents, Gas Exchange Attributes and PUE in Wheat (Triticum aestivum L.)

Abstract

A pot experiment was conducted to evaluate the foliar applied phosphorous with and without pre-plant dose (50 kg hac.⁻¹) of phosphorous on growth, chlorophyll contents, gas exchange parameters and phosphorous use efficiency (PUE) of wheat. The experiment was conducted in net house at Department of Crop Physiology, University of Agriculture Faisalabad, Pakistan. Two promising wheat cultivar AARI 2011 and FSD 2008 were used as a test crop with 5 foliar phosphorus (P) rates (0, 2, 4, 6, 8 kg ha⁻¹). The foliar applied P with pre-plant performed better than without pre-plant and control treatments. Foliar treatment of phosphorus at 6 kg ha⁻¹ P proved to be the best among other foliar treatments followed by 8 kg ha⁻¹ P. The foliar application of phosphorous at 6 kg hac.⁻¹ with pre-plant soil applied P increased the shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight and root dry weight. The chlorophyll contents (Chl. a and b) were increased with the foliar application of phosphorous. The gas exchange parameters (net carbon dioxide (CO₂) assimilation rate, transpiration rate, stomatal conductance and sub-stomatal CO₂ rate) were significantly improved by foliar applied P. The maximum values of net CO₂ assimilation rate (5.27 μ mol m⁻² sec.⁻¹), transpiration rate (3.44 μ mol m⁻² sec.⁻¹), stomatal conductance (0.81 μ mol m⁻² sec.⁻¹) and sub-stomatal CO₂ (271.67 μ mol m⁻² sec.⁻¹), were recorded in the treatment where P was foliar applied at 6 kg hac.⁻¹ with pre-plant soil applied Phosphorous. The foliar application of phosphorous with pre-plant soil applied P enhanced Phosphorous use efficiency (PUE) in both varieties. The maximum value of PUE (15.42%) was recorded in the treatment where foliar feeding of P was done at 6 kg hac.⁻¹ with pre-plant soil applied P in both genotypes.

Keywords:

• growth
• chlorophyll contents
• gas exchange
• phosphorus use efficiency
• wheat