C. Castell et al., WATER RELATIONS, GAS-EXCHANGE, AND GROWTH OF RESPROUTS AND MATURE PLANT SHOOTS OF ARBUTUS-UNEDO L AND QUERCUS-ILEX L, Oecologia, 98(2), 1994, pp. 201-211
Resprout and mature plant shoot growth, leaf water status and gas exch
ange behavior, tissue nutrient content, flowering, and production were
studied for co-occurring shallow-rooted (Arbutus unedo L.) and deep-r
ooted (Quercus ilex L.) Mediterranean tree species at the Collserola N
atural Park in Northeast Spain. Resprouts showed higher growth rates t
han mature plant shoots. During fall, no differences in eco-physiologi
cal performance of leaves were found, but mobilization of carbohydrate
s from burls strongly stimulated growth of fall resprouts compared to
spring resprouts, despite low exposed leaf area of the fall shoots. Du
ring summer drought, resprouts exhibited improved water status and car
bon fixation compared to mature plant shoots. Shoot growth of Q. ilex
was apparently extended due to deep rooting so that initial slower gro
wth during spring and early summer as compared to A. unedo was compens
ated. Tissue nutrient contents varied only slightly and are postulated
to be of minor importance in controlling rate of shoot growth, perhap
s due to the relatively fertile soil of the site. Fall flowering appea
red to inhibit fall shoot growth in A. unedo, but did not occur in Q.
ilex. The results demonstrate that comparative examinations utilizing
vegetation elements with differing morphological and physiological ada
ptations can be used to analyze relatively complex phenomena related t
o resprouting behavior. The studies provide an important multi-dimensi
onal background framework for further studies of resprouting in the Eu
ropean Mediterranean region.