© 1995 Heron Publishing—Victoria, Canada
Influence of copper on root growth and morphology of Pinus pinea L. and Pinus pinaster Ait. seedlings
Iduna Arduini (1), Douglas L. Godbold (2) and Antonino Onnis (1)
1. Dipartimento di Agronomia e Gestione dell'Agro-Ecosistema, Università degli Studi Pisa, Via S. Michele degli Scalzi 2, 56124
Pisa, Italy / 2. Forstbotanisches Institut, Universität Göttingen, Büsgenweg 2, 37077 Göttingen, Germany / Received May 9, 1994
Summary
We assessed the effects of Cu on root growth and morphology of stone pine (Pinus pinea L.) and maritime pine (Pinus pinaster Ait.) seedlings grown in culture solutions supplied with 0.012 (control), 0.1, 1 or 5 µM CuSO4. The presence of 5 µM Cu in the nutrient solution completely inhibited root growth of both species within 3 days. In both
species, taproot elongation was reduced in the presence of 1 µM Cu, although partial growth recovery occurred after 7 days
of treatment. The presence of 0.1 µM Cu in the culture solution slightly enhanced root elongation in P. pinaster, but did not significantly influence root elongation in P. pinea. In both species, root weight per unit length increased in response to Cu exposure, and in P. pinaster, root diameter was significantly increased. The Cu treatments also affected lateral root number and length. In the presence
of 1 µM Cu, both species formed only short lateral primordia. The 1 µM Cu treatment increased the lateral root index (number
of roots per cm of root length) of P. pinaster, but decreased that of P. pinea, compared with control values. Neither the 0.1 nor 1 µM Cu treatment had a significant effect on the mitotic index of either
species. We conclude that cell elongation is more sensitive to Cu than cell division. Cell membrane damage, as indicated by
Trypan blue staining, occurred after 10 days of exposure to 1 µM Cu.
Keywords:
cell division, cell elongation, heavy metal toxicity, maritime pine, membranes, mitotic index, stone pine.
