Three experiments were performed with defoliation of young cauliflower plan
ts in the field. The leaves were removed 3-6 weeks after planting and about
65% of the leaf area were removed. After defoliation, several plant proces
ses contributed to compensate for the loss of leaf area. Right after defoli
ation, the ratio of leaf area to plant weight was strongly decreased. Howev
er, during further growth the ratio of leaf area to plant weight was increa
sed in defoliated plants. Together with an increase in net assimilation rat
e it contributed to the increase in plant relative growth rate after defoli
ation. Due to higher rates of leaf growth relative to stem growth, the biom
ass allocation pattern was re-established. Specific leaf area was increased
in defoliated plants due to depletion of reserves, and contributed to the
restoration of the relationship between leaf area and plant dry weight. Con
centrations of non-structural carbohydrates were reduced after defoliation,
showing that reserves were mobilised to support re-growth. We found that c
auliflower through a number of mechanisms re-established the basic relation
ships in the plants after damage, and this observation and the estimated re
lationships can be used for modelling effects of pest damage on crop growth
. (C) 2001 Elsevier Science B.V. All rights reserved.