Page 27 - Volume 1, Issue 2, July 2008

Hellenic Plant Protection Journal 1: 79-88, 2008
Effects of Mg supply on the growth and mineral composition
of pre-rooted hardwood cuttings of “Colt” (P. avium L. x P.
pseudocerasus L.)
Y.E. Troyanos1 and N.A. Hipps2
Summary The effects of Mg supply on growth and mineral composition of pre-rooted hardwood
cuttings of “Colt” (P. avium L. x P. pseudocerasus L.) were investigated in a sand culture experiment.
The results showed that the growth of ”Colt” was increased with increasing the external supply of
Mg from 0 to 1500 μmol l-1. Mg deficiency symptoms occurred on the lower leaves and progressed
towards the apical leaves of the new shoots of the plants supplied with 0 and 150 μmol Mg l-1. When
the concentration of Mg in leaves was less than 2 mg g-1 dry weight, deficiency symptoms appeared
on the basal leaves of the plants. Mg-deficient plants had a smaller weight of plant organs, small-
er leaf area, stem diameter and new shoot extension growth than Mg-sufficient plants. The root ÷
shoot dry weight ratio was reduced with decreasing external supply of Mg. The concentrations of K,
Ca, N and P in leaves were unaffected by changes in the external supply of Mg. However, the unit ab-
sorption rates of K, Ca, N and P was increased with increasing the external supply of Mg.
Additional keywords: Cherry, magnesium, Mg deficiency, nutrient composition, shoot growth
ing solution culture system showed that
“F. 12/1” (P. avium L.) cherry variety was
more susceptible to Mg deficiency than
“Colt” (21) since it needed greater concen-
tration of Mg, [Mg] in the nutrient solution
to achieve its maximum growth.
In the present experiment, the effects
of Mg deficiency on the growth and min-
eral composition of one-year-old plants of
“Colt” were investigated. The aim of this
experiment was to define the [Mg] in the
leaves at which the plants started show-
ing symptoms of deficiency and to inves-
tigate the effect of the deficiency on the
growth and nutrient composition of the
plants.
Materials and Methods
Culture of the plants
One-year-old, pre-rooted hardwood
cuttings of “Colt” taken off hedges were
grown in black plastic pots (26 x 10 x 10
Introduction
P. avium L. is susceptible to Mg deficien-
cy (18) which causes chlorosis of the leaf
margins, necrosis and subsequent leaf ab-
scission. Differences in the susceptibility
to Mg deficiency between cherry varieties
have been found by Hipps et al. (14). These
authors working with P. avium L. seedling
and hardwood cuttings of “Colt” (P. avi-
um L. x P. pseudocerasus L.) grown in the
same soil found that the former showed
Mg deficiency symptoms whereas the lat-
ter did not. Further experiments in a flow-
1 Laboratory of Non Parasitic Diseases, Department of
Phytopathology, Benaki Phytopathological Institute,
8 St. Delta str., GR-145 61 Kifissia (Athens), Greece.
2 East Malling Research, East Malling, West Malling,
New Road, Kent, ME19 6BJ, UK.
Corresponding author:Y.Troyanos@bpi.gr
Abbreviations: [Mg]; Mg concentration, [K]; K concentra-
tion, [Ca]; Ca concentration, [N]; N concentration, [P]; P
concentration, DAP; days after transplanting planting,
DW; dry weight, LA; leaf area, UAR; unit absorption rate,
RUR; relative uptake rate and Wr;dry weight of roots.