Formation of cluster roots inAlnus incanassp.rugosaand otherAlnusspecies

摘要

Small numbers of cluster roots were found on older roots ofAlnus incanassp.rugosa(speckled alder) shrubs in the field at 2 of 11 sites. Cluster roots also formed infrequently in speckled alder grown hydroponically in complete nutrient solution. No cluster roots formed in solutions lacking P or Fe. Small numbers of cluster roots also formed inAlnus glutinosagrown hydroponically in the presence of P but not in its absence. In contrast,Alnus rubraproduced small numbers of cluster roots in the absence of P but not in its presence. No cluster roots formed inAlnus viridisssp.crispa. Cluster roots are probably not important for nutrient uptake in speckled alder because they form infrequently both in the field and in hydroponic culture.Keywords:Alnus incanassp.rugosa,Alnus glutinosa,Alnus rubra,Alnus viridisssp.crispa, cluster roots, proteoid roots.