[R] computing roots of bessel function

[coutand]

I am not yet a R user but I will be soon.
I am looking for the R command and syntax to compute the roots of Bessel 
function i.e. computing the z values that lead to Jnu(z)=0 where J is a 
Bessel function or order nu.
May You help me ?
thanks in advance.

Dr Catherine COUTAND
Institut National de la Recherche Agronomique (INRA)
umr Physiologie Intégrative de l'Arbre Fruitier et Forestier (PIAF)
234 av. du Brézet
63039 Clermont-Ferrand cedex 02
France

tel : 00-33-(0)4-73-62-46-73
fax : 00-33-(0)4-73-62-44-54
email : coutand at clermont.inra.fr
http://www.clermont.inra.fr/piaf