THE REGULATION OF BIOREGULATOR TO CALCIUM ABSORPTION AND ITS KINETICS IN APPLE ROOTSTOCK ROOTS

It has been reported that IBA can increase root activity and Ca²⁺ absorption rate in apple seedlings, and the effects can be inhibited by 2,4-DNP (Yang et al., 2004). In this experiment, we studied the effect of another bioregulator on Ca²⁺ uptake rate and the kinetics of Ca²⁺ uptake using apple rootstock seedlings (Malus hupenensis Rhed.). The results showed that CPPU (N-(2-chloro-4-pyridyl)-N’-phenylurea) increases Ca²⁺ uptake rate and Ca²⁺-ATPase activity markedly, whether applied to leaves or roots.
The effect is higher when applying to roots than that to leaves.
ABA (abscisic acid) decreased Ca²⁺ uptake rate in applications to leaves.
CPPU increased activity markedly when either applied to leaves or roots.
The rate of Ca²⁺ absorption was directly relevant to the activity of roots.
Only the treatment of CPPU to roots directly can enhance the affinity of roots to the calcium ion.
Whether applied to leaves or roots, ABA does not have any obvious influence on the affinity of root to calcium ion.
After treatment with CPPU, either to roots or to leaves, the values (=Imax/Km) all increased.
ABA applied to leaves decreased the value, but the value showed no significant change when ABA was applied to roots.

XXVII International Horticultural Congress – IHC2006: International Symposium on Endogenous and Exogenous Plant Bioregulators

Hongqiang Yang, Yuling Jie, Jia Li, Wei Zhang , Weiguo Fan

apple rootstock, roots, kinetics of Ca²⁺ uptake, ABA, CPPU, Ca²⁺-ATPase

https://doi.org/10.17660/ActaHortic.2008.774.33