Boron deficiency is identified as one of the more important causes of
poor stem form and malformed leaves in plantations of Eucalyptus globu
lus in Yunnan Province, and of Eucalyptus grandis, Eucalyptus teretico
rnis, and Eucalyptus urophylla in Guandong Province. Symptoms of B def
iciency in E. globulus were rolled and malformed leaves, stem dieback,
and a prostrate form. In E. urophylla, leaf margins became chlorotic
then necrotic, leaves turned brittle and corky, shoots died back, and
the upper stem nodes were enlarged supporting numerous short-lived axi
llary shoots. In E. grandis, stem dieback was preceded by the basipeta
l accumulation of anthocyanin in leaves. Boron-deficient E. tereticorn
is leaves developed marginal and interveinal chlorosis and recurved ma
rgins. Depressed foliar B concentrations were associated with visible
symptoms. In E. globulus, the mean B concentration in young leaves of
healthy trees was 31 mg/kg dry matter compared with 10 mg/kg in prostr
ate trees. Symptoms did not appear in E. globulus trees supplied with
B fertilizer at planting. Normal shoot growth was restored in E. uroph
ylla by the addition of B to the soil.