BACKGROUND AND AIMS Dryopteris crassirhizoma is a semi-evergreen fern growing on the floor of deciduous forests. The present study aimed to clarify the photosynthetic and storage functions of overwintering leaves in this species. METHODS A 2-year experiment with defoliation and shading of overwintering leaves was conducted. Photosynthetic light response was measured in early spring (for overw...

We find computable criteria for stability of symplectic leaves of Poisson manifolds. Using Poisson geometry as an inspiration, we also give a general criterion for stability of leaves of Lie algebroids, including singular ones. This not only extends but also provides a new approach (and proofs) to the classical stability results for foliations and group actions.

This result is also due independently to G. Hector [3], who has shown how useful it can be in understanding the geometry of certain foliated manifolds. In such applications one sometimes needs a form of this theorem which applies to foliated subspaces, for example a minimal subset of a foliation. In fact our proof goes through unaltered in the situation where M is a locally compact, paracompact...