Magda D, Warembourg F R, Labeyrie V
IBEAS, Avenue de l'Université, Campus Universitaire, F-64000, Pau, France.
C.E.P.E., L. Emberger, C.N.R.S., BP 5051, F-34033, Montpellier Cedex, France.
Oecologia. 1988 Nov;77(2):255-260. doi: 10.1007/BF00379195.
Lathyrus sylvestris is a pioneer legume often found in disturbed habitats. Mainly reproduced through vegetative propagation, this clonal species presents a system of ramets that remain connected for several years. The existence of carbon transfer among ramets within a clone has been studied using C in situ. Assimilate translocation from primary to secondary ramets was observed in all clones when the primary ramet was exposed to CO. The amount of transfer ranged from trace up to 90% of the total C incorporated. However, in only half of the clones there was consistent enrichment of the secondary ramet (5 to 89%) suggesting that interramets transfer of carbon may be facultative. Furthermore, when significant export occurred from the primary ramet, it was always principally towards only one ramet even when the clone included more than one. The transfer of C from secondary to primary ramets was shown to be significant only when photosynthesis of the latter was decreased by shading. In this case import of carbon was never more than 60% of the incorporated C.No correlation was found between age or size of the ramets and the intensity of transfer. The shading effect let suppose that transfers are mainly driven by carbon limitation due to changing environmental conditions and not to the state of ramet maturity. The adaptative advantage of such facultative physiological integration between ramets of a clone is discussed.
香豌豆是一种先锋豆科植物，常见于受干扰的生境中。这种克隆植物主要通过营养繁殖，其分株系统可保持数年相连。已利用原位碳研究了克隆体内分株间的碳转移情况。当初级分株暴露于二氧化碳时，在所有克隆中均观察到同化物从初级分株向次级分株的转运。转运量从微量到总固定碳的90%不等。然而，只有一半的克隆中次级分株存在持续富集现象（5%至89%），这表明碳在分株间的转移可能是兼性的。此外，当从初级分株有大量输出时，即使克隆包含多个分株，其输出也总是主要朝向一个分株。只有当次级分株的光合作用因遮荫而降低时，才显示出碳从次级分株向初级分株的显著转移。在这种情况下，碳的输入从不超过固定碳的60%。未发现分株的年龄或大小与转移强度之间存在相关性。遮荫效应表明，转移主要是由环境条件变化导致的碳限制驱动的，而非分株的成熟状态。本文讨论了克隆分株间这种兼性生理整合的适应性优势。
