Characterizing Root Responses to Low Phosphorus in Pearl Millet [Pennisetum glaucum (L.) R. Br.]

• Published in: Agronomy journal Vol. 98; no. 5; pp. 1187 - 1194
• Main Authors: Faye, I, Diouf, O, Guisse, A, Sene, M, Diallo, N
• Format: Journal Article
• Language: English
• Published: Madison American Society of Agronomy 01.09.2006
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; cultivars; drought; dry matter accumulation; Fundamental and applied biological sciences. Psychology; Genetics and breeding of economic plants; hydroponics; leaf water potential; millets; nutrient availability; nutrient use efficiency; Pennisetum glaucum; phosphorus; phosphorus fertilizers; plant nutrition; root growth; root hairs; root systems; roots; sandy soils; shoots; Varietal selection. Specialized plant breeding, plant breeding aims; water stress; Senegal; Non metal; Monocotyledones; Nutrition; Root; Soil fertility; Pennisetum glaucum; Phosphorus; Inorganic element; Cereal crop; Response; Group VA element; Gramineae; Agronomy; Angiospermae; Vegetative apparatus; Spermatophyta
• ISSN: 0002-1962; 1435-0645
• DOI: 10.2134/agronj2005.0197

Adaptation to low water and soil P availability has been related to root properties. Two experiments were conducted in a greenhouse. Under hydroponics conditions, plants of the Souna 3 cultivar were grown for 30 d with three levels of P (P0 = 0.0 mol L-1, P1 = 0.073 10(-3) mol L-1, and P2 = 1.65 10(-3) mol L-1). In the pot experiment, two cultivars (Souna 3 and IBMV8402) were planted in pots filled with 19 kg of P-deficient and sandy soil and subjected to two watering regimes: well watered and water stressed at the vegetative phase from 23 d after sowing (DAS) to 30 DAS. Phosphorus treatment consisted of two levels: application of phosphate fertilizer (P2O5) at the rate of 649 mg per pot (34 mg P2O5 kg-1 soil), referred to as F1, and no phosphate application, referred to as F0. The results showed that under P deficiency, pearl millet [Pennisetum glaucum (L.) R. Br.] presented an alteration of root parameters, particularly root volume, by the formation of root hair. Under non-water-limited conditions as well as in high or low P, IBMV8402 showed a better root and shoot growth. However, under drought conditions, the leaf water potential (psi f) of IBMV8402 (psi f = -5 MPa) decreased more than that of Souna 3 (psi f = -3 MPa). In spite of this, P supply improved the root and shoot growth of IBMV8402. Finally, except for the condition of water stress and without P supply, P utilization efficiency exhibited by IBMV8402 was 20 to 50% higher than that of Souna 3 on the basis of shoot biomass production.