IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
artículos
Título:
Trade-off between seed number and weight: influence of a grass-endophyte symbiosis.
Autor/es:
GUNDEL, P.E.; GARIBALDI L; MARTINEZ-GHERSA MA; GHERSA CM
Revista:
BASIC AND APPLIED ECOLOGY
Editorial:
ELSEVIER GMBH, URBAN & FISCHER VERLAG
Referencias:
Lugar: ALEMANIA; Año: 2012 vol. 13 p. 32 - 39
ISSN:
1439-1791
Resumen:
Plant fitness is enhanced by resource allocation to seed number (offspring number) or weight (offspring survival). Besides,there is a well known trade-off in resource allocation between both traits. Symbiotic interactions can influence plant resourceallocation to reproduction, yet little research has been performed in this direction.We studied the consequences of a grass?fungussymbiosis on the trade-off between seed number and weight, using Lolium multiflorum and the endophyte Neotyphodiumoccultans as our study system. In ecological terms, we experimentally removed N. occultans from L. multiflorum plants, andcompared reproductive allocation to seed number and weight in endophyte-symbiotic vs. non-symbiotic plants at differentlevels of nutrient availability (small pots vs. large pots). In evolutionary terms, we compared reproductive allocation betweensymbiotic vs. non-symbiotic plants for different host genotypes. All plants showed a negative association between seed numberand weight, once standardized for total reproductive biomass. Under high nutrient availability, endophyte-symbiotic plantsshowed higher seed weight than non-symbiotic plants for any seed number. However, no differences were observed under lownutrient availability. Endophyte influence also varied according to L. multiflorum genotype; specifically, endophyte-symbioticplants showed a lower slope in the relationship between seed number and weight than non-symbiotic plants for the ?Marshall?genotype but no endophyte influence was found for the ?Pampean? genotype. The results implied a higher plasticity in seedweight and lower plasticity in seed number for symbiotic plants. Indeed, endophyte-symbiotic plants showed an overall lowerslope in the association between seed number and total reproductive biomass than non-symbiotic plants. Our results suggestthat N. occultans induces heavier seeds in L. multiflorum plants under environmental conditions favorable to plant growth orfor certain plant genotypes. We propose that symbiotic interactions may influence the evolution of seed number and weighttrade-off.