Estudo anatômico do haustório da erva-de-passarinho (Struthanthus marginatus (desr.) blume), em diversas plantas, em Viçosa

Resumo

The development of hautoria of de plant parasite (Struthanthus marginatus (Desr. ) Blume) is described for tenplants studied. The phenomena of scarring in orange tree is studied, also.

From the difference in behavior observed betweenhost and parasite, the authors have classifield plant tested into five group or types as follows:

1) Type observed in cupress (Cupressus sp.) in which destruction of the host is direct and rapid.

2) Type observed in acalypha (Acalypha sp.). In this plant regression of aportion of the parenchyma cells occur followed by absorption by the parasite.

3) Type observed in the China-berry (Melia azedarach L.) which is the most commonly observed reaction in Viçosa, The plant offers certain resistance against invasion, however,infection occurs to a certain degree.

4) Type observed imprivet (Ligustrum sp.) in which develop- ment of haustoria is almost exclusively limited to the region of the bark, rarely penetrating the wood. In cases where haustoria penetrated the wood, these were rapidly repelled,

5) Type observed in bougainvillea (Bougainvillaea sp.).In spite of large numbers of germinating seeds, penetration was not observed.

Seeds which germinate on the leaves generally do not suceed indeveloping, possibly due to lack of nutrients arbecause ofthe thinness of leaves which is insufficientto supportthe total development of haustoria. The seedlings ultimately fall, leaving perforation in the leaves.

The phenomena of " scarrig'' which is relatively rapid, was observed in orange after removal of the haustoria of Struthanthus marginatus. When remains of the haustoria remained within the branch, an enlarged protuberane formed and the process of "acarring' was delayed.

In Viçosa, fruiting occurs during the months of August and September,