Biomass Partitioning and Root System Development of Acid Lime (Citrus aurantifolia Swingle) Seedlings under Contrasting Growing Media and Nutrient Regimes in a Shade-Net Nursery

Abstract

The quality of citrus nursery stock depends not only on shoot growth but also on the development and proportional allocation of root and shoot biomass. A secondary analysis was undertaken using the root and biomass observations from an acid lime (Citrus aurantifolia Swingle) cv. Sai Sharbati nursery experiment conducted during 2025–26 at Sweet Orange Research Station, Badnapur. The original experiment comprised seven media–nutrition treatments in a Completely Randomized Design with three replications. The present manuscript focuses specifically on root biomass, shoot biomass, root volume and biomass partitioning rather than the germination and general growth response reported in the associated publication. The integrated potting mixture + cocopeat medium supplied with 20:10:10 g NPK seedling⁻¹ (T7) produced the highest root fresh weight (3.45 g), root dry weight (0.68 g), shoot fresh weight (16.55 g), shoot dry weight (4.19 g) and root volume (3.89 cm³). Potting mixture + cocopeat with 40:25:25 NPK (T6) and potting mixture with 40:25:25 NPK (T3) were the next strongest treatments for biomass production. Although the sole cocopeat treatment with 60:25:25 NPK (T4) showed the highest root:shoot dry ratio (0.59), its absolute root and shoot biomass were very low, demonstrating that a high ratio alone is not an indicator of superior seedling quality. T7 combined substantial absolute root development with markedly greater shoot biomass and therefore showed the most favourable overall biomass architecture. The findings highlight the importance of evaluating absolute root traits together with biomass allocation when selecting acid lime seedlings for nursery transplanting.