Uptake and Distribution of Arsenic in Chickpea: Effects on Seed Yield and Seed Composition

Abstract

Chickpea plants were grown in arsenic (As)–contaminated soils (5 mg kg⁻¹ of dry soil) and investigated for As uptake, distribution, and effects on growth, yield, and quality of seeds. The roots accumulated the greatest As (7 mg kg⁻¹ dry weight), followed by stem (4.8 mg), leaves (4.0 mg), and seeds (0.7 mg). Arsenic inhibited the growth of the roots and shoots (as dry weight) by 65% and 60%, respectively, over controls. The shoot/root ratio declined from 4.3 in the control to 3.5 in As-treated plants. The seed yield (g) and number of pods plant⁻¹ decreased by 66 and 53%, respectively, over controls. A marked increase in membrane damage coupled with reduction in chlorophyll and relative leaf water content occurred in As-treated plants. The contaminated plants showed 34% and 25% decrease over control in sucrose content in their leaves and seeds, respectively. The accumulation of seed reserves such as starch, proteins, sugars, and minerals was inhibited significantly due to As-treated plants. Storage proteins such as albumins, globulins, glutelins and prolamins decreased significantly with larger effect on glutelins. The contents of minerals such as calcium (Ca), phosphorus (P), and iron (Fe) declined greatly in the seeds of As-treated plants. The accumulation of amino acids such as lysine, methionine + cystine, phenylalanine + tyrosine, proline, threonine, tryptophan, and valine was inhibited significantly in the seeds of As-applied plants compared to the control. The findings indicated that As application markedly reduced the quality of the chickpea seeds, especially in terms of proteins and minerals.

Keywords:

• Arsenic
• chickpea
• nutrition
• seed composition
• storage proteins