Variation in P-acquisition ability and acid phosphatase activity at the early vegetative stage of lentil and their validation on P-deficiency field

Plant available phosphorus (P) is limited in the vast rice-fallow areas where the soil is mainly acidic. Screening of fifty lentil genotypes in soil cylinder filled with solid-phase P-buffer identified genotypes with high P-acquisition ability even though desorbed P was 100 μmol/g only. Genotypes with high P-acquisition ability were identified based on their almost equal P-acquisition ability both in P-deficient and sufficient conditions. Root dry weight and root surface area showed a significant positive correlation with shoot phosphate content in P-deficiency condition, but not in P-sufficiency condition. Identified top three tolerant genotypes, namely IC560183, WBL77, and BM3 showed a 30% reduced seed yield in P-deficient field as compared to 60% or more reduction by intolerant genotypes. In P-Deficiency condition, 4–6 times high intercellular acid phosphatase activity in roots of the tolerant genotypes may be one of the factors for high P-acquisition. Higher external secretion of acid phosphatase in tolerant genotypes was also confirmed by blue colour through 5-bromo-4-chloro-3-indolyl-phosphate (BCIP) staining. P-deficiency tolerant lentil genotypes will be useful in expansion and enhancing the productivity of lentil in vast rice-fallow areas, mostly where plant-available P is low.