Influence of nutrient deficiency on root architecture and root hair morphology of trifoliate orange (Poncirus trifoliata L. Raf.) seedlings under sand culture

Root hairs are important to plants for nutrient and water uptake through providing an increased absorptive surface area and exploitable soil volume. Citrus, as one of the most important fruit crops in the world, is generally believed to have few or even no root hair in the field and thus strongly depends on arbuscular mycorrhizas. In this study, sand culture experiment was carried out to investigate the effect of different nutrient deficiency conditions on the root hair development and root growth of one-month-old Poncirus trifoliata seedlings. We demonstrated that root hairs were distributed asymmetrically in the whole root, indicating it might be one of the characteristics of the citrus root hair distribution. Furthermore, the density and length of root hair were much higher in P, Ca deficiency than the control, however, lower in K-deficiency, implying the critical role of those nutrients in root hair initiation and elongation. Additionally, root growth was hampered at Ca, Mg, Fe, or Mn deprivation condition, suggesting that it is necessary to supply sufficient those mineral nutrients at seedling stage to ensure better root architecture. (C) 2013 Elsevier B.V. All rights reserved.