Physiological integration among ramets of Lathyrus sylvestris L.

Abstract

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 toCO. 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 ofC 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.

TRANSPORT OF CARBON AMONG CONNECTED RAMETS OF EICHHORNIA CRASSIPES (PONTEDERIACEAE) AT NORMAL AND HIGH LEVELS OF CO2

“…A number of other clonal plant species appear to transport little or no carbon among connected ramets when resource levels are uniform (e.g., Flanagan and Moser, 1985;Pitelka and Ashmun, 1985;Welker et al, 1985). Even when connected ramets are given contrasting levels of light, there may still be no apparent carbon transport between ramets located on different stolons, from younger to older ramets, or from a parent ramet to more than one offspring ramet at a given time (Slade and Hutchings, 1987;Magda, Warembourg, and Labeyrie, 1988).…”

“…2 Author for correspondence, current address: Botany Department, University of Massachusetts, Amherst, MA 01003. least partly controlled by the relative amounts of carbon that each ramet acquires directly through photosynthesis. Evidence for this comes from experiments showing that a ramet imports greater amounts of carbon from connected ramets if its photosynthesis is reduced by shading, defoliation, or water stress (e.g., Alpert and Mooney, 1986;Magda, Warembourg, and Labeyrie, 1988;Jonsdottir and Callaghan, 1989;Thomas, Schiele, and Damberg, 1990).…”

Differential sectoriality in long-distance transport in temperate tree species: evidence from dye flow, 15N transport, and vessel element pitting

“…Among dicotyledons, there is evidence for differential sectoriality. Clonal dicotyledons appear to be more integrated than non-clonal dicotyledons (Watson and Casper 1984;Alpert 1991;Price et al 1996), perhaps because the success of many clonal species requires sharing of resources among ramets (e.g., Magda et al 1988;Alpert 1991;Birch and Hutchings 1994;Stuefer and Hutchings 1994;Wijesinghe and Handel 1994;Kemball and Marshall 1995). Nonclonal dicotyledons also differ in sectoriality.…”

Plants as resource mosaics: a functional model for predicting patterns of within‐plant resource heterogeneity to consumers based on vascular architecture and local environmental variability

“…Selection may have favored vascular integration in clonal plants as compared to unitary plants (Watson and Casper 1984, Alpert 1991, Price et al 1996. The success of many clonal plant species depends upon the sharing of resources -photosynthates and nutrientsamong ramets (e.g., Magda et al 1988, Alpert 1991, Birch and Hutchings 1994, Stuefer and Hutchings 1994, Wijesinghe and Handel 1994, Kemball and Marshall 1995, D'Hertefeldt and Jó nsdó ttir 1999. For example, the clonal herb Glechoma hederacea moves resources between ramets and its growth is greatest when soil nutrients are patchily distributed (Birch and Hutchings 1994).…”