Variation in root morphological and physiological traits and nutrient uptake of chickpea genotypes

Tara Gahoonia, Rawshan Ali, Rajinder Malhotra, Ahmed Jahoor, M. Rahman. (6/6/2007). Variation in root morphological and physiological traits and nutrient uptake of chickpea genotypes. Journal of Plant Nutrition, 30 (6), pp. 829-841.

Abstract

Plant nutrients such as potassium (K), phosphorus (P), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) mostly remain fixed in soils and their bio-availability to plant roots is diffusion-limited. Hence, superior root traits, that can enhance their dissolution and capture from the soils, can play a central role in its productivity. Root morphological (root length and root hairs) and physiological traits (root exudation of protons and phosphatase enzymes) of ten selected varieties/breeding lines of chickpea (Bari-chhola3, Bari-chhola-4, Bari-chhola-5, Bari-chhola-6, Bari-chhola-7, Bari-chhola-8, BGME7, ICCV-98926, ICCV-94924, and ICCV-98916) were studied and related them to the uptake of the nutrients in a pot experiment. There were significant (P < 0.05) genotypic differences in root length (RL) and root hair length (RHL). The RL ranged between 70 m plant(-1) and 140 m plant(-1). The variation in RHL was significant (P < 0.05) and it ranged between 0.58 +/- 0.09 mm (Bari-chhola-5) and 0.26 +/- 0.09 mm. The root hair density (RHD, number mm(-1) root) varied between 13 2 and 21 13 among the genotypes. The presence of root hairs increased the effective root surface area (e.g., Bari-chhola-5) up to twelve times. The genotypes differed in their ability to acidify the rooting media in laboratory agar studies, with Bari-chhola-5 inducing most acidification followed by Bari-chhola-3. The ability of Bari-chhola-5 to acidify the rhizosphere was also confirmed by embedding in situ roots in the field in an agar-agar solution containing pH indicator dye Bromocresol purple.