CHILLING REQUIREMENT, DYNAMIC AND HETEROGENEITY OF BUDS DORMANCY ON BRANCHES OF Salix x rubens CULTIVATED IN LAGES, SC

Abstract

A intensidade de dorm\ueancia e o requerimento em frio do vimeiro (Salix x rubens Shrank) foram avaliados pelo m\ue9todo de estacas de gema isolada. As observa\ue7\uf5es foram realizadas em ramos coletados em Lages, SC, a intervalos regulares de 21 dias, de 29/03/2004 a 2/08/2004. A brota\ue7\ue3o de gemas dos segmentos basal, mediano e distal de ramos do ano foi avaliada na aus\ueancia ou ap\uf3s suplementa\ue7\ue3o de frio (500 ou de 1000 horas a 5 \ub1 3\ub0C). A brota\ue7\ue3o de gemas foi avaliada nos est\ue1dios: a) gemas inchadas; b) in\uedcio da abertura das gemas; c) broto alongado e; d) broto alongado com folha aberta. A intensidade de dorm\ueancia das gemas foi crescente da base para a ponta dos ramos e foi m\ue1xima em 10 de maio, para todas as regi\uf5es do ramo. O tratamento com 500 horas de frio foi efetivo em reduzir o tempo para a brota\ue7\ue3o, em todas as \ue9pocas e posi\ue7\uf5es das gemas no ramo. A avalia\ue7\ue3o at\ue9 o aparecimento de folhas abertas foi importante para identificar a real capacidade de brota\ue7\ue3o das gemas.The dormancy intensity and chilling requirement of willow (Salix x rubens Shrank) were investigated in excised single node shoots. Observations were made from branches collected in Lages, Santa Catarina State, Brazil, at 21 days interval from March, 29th to August 2and, 2004. Budburst of buds from bottom, middle, and top segments of branches under natural chilled or completed with artificially chill by 500, and 1000 hours at 5\ub13\ub0C was evaluated. The sprouted were evaluated at wetting bud, expose bud; steam larded and opened leaf station. The most intensive dormancy occurred on May 10th and it was improved from the basal to top part of the branches. The chill treatment with 500 hours at 5\ub13\ub0C was effective in reducing the time to budburst. The real ability of bud development can be assessed only if observations are carried out until appearance of opened leaves