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

Abstract

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 10−3mol 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 (Ψf) of IBMV8402 (Ψf = −5 MPa) decreased more than that of Souna 3 (Ψf = −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.

Drought Stress Tolerance in Wheat and Barley: Advances in Physiology, Breeding and Genetics Research

“…Water limitations accompanied by low N is the main constraint to wheat yield which affected the leaf–water relations, chlorophyll fluorescence and photosynthetic processes leading to restricted plant growth rate, early senescence, reduced grain filling duration with limited grain weight and poor crop productivity [36]. As the water content in the soil decreases, the radius of water-filled pores decrease, tortuosity increases and P mobility decreases [37]. A decline in available P reduces P uptake and consequently reduces foliar P content [38].…”

Pearl Millet Inbred and Testcross Performance under Low Phosphorus in West Africa

“…The varietal differences in nutrient efficiency are based on genetic variation in physiological or morphological characters. Brück et al (2003) and Faye et al (2006) reported pearl millet genotypic differences in root and shoot parameters in fields with P deficiency and in hydroponic conditions, respectively. However, these studies only included a few genotypes.…”

“…Brück et al (2003) and Faye et al (2006) reported pearl millet genotypic differences in root and shoot parameters in fields with P deficiency and in hydroponic conditions, respectively. Brück et al (2003) and Faye et al (2006) reported pearl millet genotypic differences in root and shoot parameters in fields with P deficiency and in hydroponic conditions, respectively.…”

Phosphorus uptake and utilization efficiency in West African pearl millet inbred lines

“…Several studies have reported genetic variation for low P tolerance in WA pearl millet. Beggi et al (unpublished), Brück et al (2003) and Faye et al (2006) reported genotypic differences for pearl millet in root and shoot parameters in pot experiments, fields with P deficiency and in hydroponic conditions, respectively. In their work, Beggi et al (unpublished) showed genotypic differences for P uptake and P utilization efficiencies in a wide range of pearl millet open pollinated varieties.…”

“…Low-P tolerance in WA pearl millet has been studied mainly based on morpho-physiological attributes (Bationo et al, 1993;Buerkert et al, 2001;Brück et al, 2003;Faye et al, 2006;Beggi et al, unpublished) but most of these studies were only based on a few genotypes. Genetic variation has been reported for rooting parameters as well as fertilizer response in WA pearl millet (Manga and Saxena, 1988;Brück et al, 2003;Faye et al, 2006). Furthermore, Beggi et al (unpublished) have shown genotypic differences for PE under pot trial conditions in WA pearl millet landrace varieties.…”