PHYTOCHEMISTRY AND CHEMOSYSTEMATICS OF
MELIACEAE: A CONTRIBUTION TO SOLVE THE
SILVICULTURAL PROBLEM OF CEDRELA

 

Efforts to establish large scale homogeneous plantations of native Meliaceae have almost invariably failed due to larval attacks by the shoot borer Hypsipyla (Lepidoptera: Pyralidae). The host range of this oligophagous pantropical genus is limited principally to the Swietenioideae. Of this sub-family, important species of the genera Khaya and Entandrophragma in Africa, Swietenia and Cedrela in Latin America and Toona in Asia and Australia are attacked. However, Toona ciliata introduced to Brazil shows excellent growth and an absence of attacks by H. grandella, in contrast to the native Cedrela odorata. The latter has been grafted to stems of T. ciliata and the resistance has been translocated from the Toona stock to the Cedrela graft.

The chemistry of these grafts have not been previously studied. Thus, we have been examining the stem of C. odorata grafted on T. ciliata var. australis, in order to determine if secondary metabolites present in the latter could be translocated into the former.
The known limonoids from Cedrela are typical of the Swietenioideae. On the other hand, Toona appear to be peripheral Melioideae as well as Swietenioideae. Clearly much more detailed phytochemical investigations of Toona species will be essential for a better understanding of its chemotaxonomic position in the Meliaceae1,2. Thus we have also been working with all organs of Toona ciliata. Antifeeding activity against the larvae of the Hypsipyla grandella have been determined.

Speculations on the silvicultural problem of Cedrela will be discussed on the basis in our results.

 

1. Agostinho, S.M.M.; Silva, M.F. das G.F. da; Fernandes, J.B.; Vieira, P.C.; Pinheiro, A.L.; Vilela, E.F.; Limonoids from Toona ciliata and their Chemosystematic and Speculative Ecological Significance. Biochemical Systematics and Ecology, 22, 323-328, 1994.

 

2. Oiano Neto, J.; Agostinho, S.M.M.; Silva, M.F. das G.F. da; Vieira, P.C.; Fernandes, J.B.; Pinheiro, A.L.; Vilela, E.V.; Limonoids from Seeds of Toona ciliata and their Chemosystematic Significance. Phytochemistry, 38, 397-401, 1995.