THE EFFECT OF IBA ON THE CA²⁺ ABSORPTION AND CA²⁺-ATPASE ACTIVITY AND THEIR ULTRACYTOCHEMICAL LOCALIZATION IN APPLE ROOTS

The uptake rate of Ca²⁺ and Ca²⁺-ATPase ultracytochemical localization were studied using Malus hupenensis Rehd seedlings and pot-cultured two-year-old apple trees (‘Starkrimson’/Malus hupenensis Rehd), after treatment with IBA. The results showed, IBA increased activity of roots and Ca²⁺-ATPase and rate of Ca²⁺ uptake.
But Ca²⁺ uptake rates were inhibited by 2,4-DNP, the metabolic inhibitor, and the inhibition degree was higher under low Ca²⁺ concentrations (0 ~ 0.5 mmol/L) than high Ca²⁺ concentrations (0.5 ~ 5 mmol/L). The K_m and I_max and the ratio (I_max/K_m) all increased, and the inhibition degrees were higher in excised root than intact roots after roots were treated with IBA. The Imax and a (I_max/K_m) increased but the K_m after spraying IBA on leaves. 2,4-DNP inhibited the effects of IBA on Ca²⁺ absorption.
Ca²⁺-ATPase was located on the cytoplasmic membrane and the vacuolar membrane.
The activity of Ca²⁺-ATPase on the cytoplasmic membrane was increased significantly after treating by IBA.

XXVI International Horticultural Congress: Key Processes in the Growth and Cropping of Deciduous Fruit and Nut Trees

Y. Hong-Qiang, J. Yu-Ling, Z. Lian-Zhong, C. Ming-Gang

Malus hupenensis, roots, auxin, calcium, uptake, Ca²⁺-ATPase, location

https://doi.org/10.17660/ActaHortic.2004.636.26