Seed Weight and Trade-Offs: An Experiment in False Rhodes Grasses under Different Aridity Conditions.

MARINONI L.; ZABALA J.M.; QUIROGA R; RICHARD G.A.; PENSIERO J.F.

Plants

MDPI

Lugar: Basel; Año: 2022

2223-7747

The false Rhodes grasses [Leptochloa crinita (Lag.) P.M. Peterson and N.W. Snow andLeptochloa pluriflora (E. Fourn.) P.M. Peterson and N.W. Snow] are considered valuable native forageresources for arid and semiarid rangelands in Argentina and the United States. Effectively usingplant materials as forage under aridity conditions requires understanding their resource allocationunder those conditions. In the present study, plant functional traits were evaluated in six populationsof each false Rhodes grass species from different geographic origin in a humid and an arid region.The evaluation was focused on seed weight, due to the key role of this trait in plant survival.The implication of seed weight in germination under osmotic stress and trade-off relationshipsbetween functional traits were also analysed. A fixed ontogenetic variation was found in bothspecies, since populations maintained a stable seed weight across environments. The tolerance toosmotic stress at germination stage was more related to seed weight than to population origin ormaternal environment of seeds; heavier-seeded populations produced heavier seedlings insteadof a higher number of germinated seeds or higher germination rates. Some traits varied betweenenvironments but other traits exhibited a fixed response. Variation patterns among populationswere similar within environments and in some cases even for populations from the same geographicorigin, revealing a fixed ontogenetic variation; this phenomenon was clearer in L. crinita than inL. pluriflora. Moreover, several different trade-off strategies were detected in both species. Theseresults reinforce the knowledge about the key role of seed weight in survival and performance ofseedlings at initial growth stages under arid conditions; however, at advanced stages, other traitswould have an important function in growth and development of false Rhodes grasses.