plastic responses to temporal variation in moisture availability: consequences for water use eyciency and plant performance | 量子荧光|微型光纤光谱仪-ag贵宾会

the ability to appropriately modify physiological and morphological traits in response to temporal variation should increase wtness. we used recombinant hybrid plants generated by crossing taxa in the piriqueta caroliniana complex to assess the evects of individual leaf traits and trait plasticities on growth in a temporally variable environment. recombinant hybrids were used to provide a wide range of trait expression and to allow an assessment of the independent evects of individual traits across a range of genetic backgrounds. hybrid genotypes were replicated through vegetative propagation and planted in common gardens at archbold biological station in venus, florida, where they were monitored for growth, leaf morphological characters, and integrated water use eyciency (wue) (c isotope ratio; 13c) for two successive seasons. under wet conditions only leaf area had signiwcant evects on plant growth, but as conditions became drier, growth rates were greatest in plants with narrow leaves and higher trichome densities. plants with higher wue exhibited increased growth during the dry season but not during the wet season. wue during the dry season was increased for plants with smaller, narrower leaves that had higher trichome densities and increased rexectance. examination of alternative path models revealed that during the dry season leaf traits had signiwcant evects on plant growth only through their direct evects on wue, as estimated from 13c. over the entire growing season, plants with a greater ability to produce smaller and narrower leaves with higher trichome densities in response to reduced water availability had the greatest growth rate. these wndings suggest that plants making appropriate changes to leaf morphology as conditions became dry had increased wue, and that the ability to adjust leaf phenotypes in response to environmental variation is a mechanism by which plants increase wtness.