Larmure Annabelle, Salon Christophe, Munier-Jolain Nathalie G
ENESAD, Département Agronomie et Environnement, 26 bd Dr Petitjean, BP 87999, 21079 Dijon cedex, France.
INRA, Unité de Génétique et d'Ecophysiologie des Légumineuses, 17 rue Sully, BP 86510, 21065 Dijon cedex, France.
Funct Plant Biol. 2005 Nov;32(11):1009-1017. doi: 10.1071/FP05154.
The effect of moderate temperature on seed N concentration during the seed-filling period was evaluated in pea (Pisum sativum L.) kept in growth cabinets and the relation between plant assimilate availability and the variation of seed N concentration with temperature was investigated. Seed N concentration of pea was significantly lowered when temperature during the seed-filling period decreased from a day / night temperature of 25 / 20°C to 15 / 10°C. Our results demonstrate that during the seed-filling period mechanisms linked with assimilate availability can modify seed N accumulation rate and / or seed-filling duration between 25 / 20°C and 15 / 10°C. At the lower temperature (15 / 10°C), an increased C availability resulting from an enhanced carbon fixation per degree-day allowed new competing vegetative sinks to grow as pea is an indeterminate plant. Consequently N availability to filling seeds was reduced. Because the rate of seed N accumulation per degree-day mainly depends on N availability to filling seeds, the rate of seed N accumulation was lower at the low temperature of our study (15 / 10°C) than at 25 / 20°C while seed growth rate per degree-day remains unaffected, consequently seed N concentration was reduced. Concomitantly, the increased C availability at the lower temperature prolonged the duration of the seed-filling period.
在生长箱中培养的豌豆（Pisum sativum L.）上评估了适度温度对种子灌浆期种子氮浓度的影响，并研究了植物同化物可用性与种子氮浓度随温度变化之间的关系。当种子灌浆期的温度从昼夜温度25/20°C降至15/10°C时，豌豆的种子氮浓度显著降低。我们的结果表明，在种子灌浆期，与同化物可用性相关的机制可以在25/20°C和15/10°C之间改变种子氮积累速率和/或种子灌浆持续时间。在较低温度（15/10°C）下，由于每度日碳固定增强导致碳可用性增加，使得新的竞争性营养库得以生长，因为豌豆是一种无限生长型植物。因此，灌浆种子的氮可用性降低。由于每度日种子氮积累速率主要取决于灌浆种子的氮可用性，在我们研究的低温（15/10°C）下，种子氮积累速率低于25/20°C时，而每度日种子生长速率不受影响，因此种子氮浓度降低。同时，较低温度下增加的碳可用性延长了种子灌浆期的持续时间。
