INSTITUTO DE FISIOLOGIA VEGETAL
Unidad Ejecutora - UE
The control of autumn senescence in European aspen
YVAN FRACHEBOUD; VIRGINIA LUQUEZ; LARS BJÖRKÉN; ANDREAS SJÖDIN; HANNELE TOUMINEN; STEFAN JANSSON
AMER SOC PLANT BIOLOGISTS
Lugar: Rockville, USA; Año: 2009 p. 1982 - 1982
The initiation, progression and natural variation of autumn senescence in European aspen (Populus tremula) was investigated by monitoring chlorophyll degradation in i) trees growing in natural stands and ii) cloned trees growing in a greenhouse under various light regimes. The main trigger for the initiation of autumn senescence in aspen is the shortening photoperiod, but there was large degree of variation in the onset of senescence, both within local populations and amongst trees originating from different populations, where it correlated with the latitude of their respective origins. The variation for onset of senescence with a population was much larger than the variation of bud set. Once started, autumn senescence was accelerated by low temperature and longer nights, and clones that started to senescence late had a faster senescence. Bud set and autumn senescence appeared to be under the control of two independent critical photoperiods, but senescence could not be initiated until a certain time after bud set, suggesting that bud set and growth arrest is important for the trees to acquire competence to respond to the photoperiodic trigger to undergo autumn senescence. A timetable of events related to bud set and autumn senescence is presented.