The effects of salt, manganese, and density on life history traits in Hesperis matronalis L. from oldfield and roadside populations

Abstract

Plant communities in the verges of major roadways (roadsides) are similar to those of abandoned farm fields undergoing succession (oldfields). However, roadsides are subject to distinctive stresses. Here, we look at local adaptation in Hesperis matronalis L. to salinity and manganese (Mn). Plants collected from three roadside and three oldfield populations were grown in a greenhouse under controlled, high-salinity, and high-Mn conditions, and several life history traits were measured. In addition, we imposed a density treatment after vernalization. Mortality was high in both the salt (43% survival) and Mn treatments (53% survival) compared with the control (71% survival). Distinct family, population, and site variation was found in measures of plant size. There were also family-level differences in response to soil treatments. However, none of our results were consistent with local adaptation. In general, larger plants were more likely to bolt, and oldfield plants were less likely to bolt than roadside plants in all treatments (in the low-density treatment, 56% of roadside plants had bolted compared with only 16% of oldfield plants). We found that the high-density treatments resulted in earlier bolting and longer internodes, a result consistent with the shade avoidance hypothesis.Résumé : Les communautés végétales en marge des routes principales (bords de route) sont semblables à celles des terres agricoles abandonnées en succession (vieilles prairies). Cependant, les bords de route sont soumis à des stress particuliers. Les auteurs examinent l'adaptation locale de l'Hesperis matronalis L. à la salinité et au manganèse (Mn). Ils ont cultivé en serres, sous des conditions contrôlées impliquant de fortes teneurs en sel et en manganèse, des plantes récoltées sur les bords de trois routes et à partir de trois populations de vieilles prairies, et ont mesuré plusieurs aspects de leur cycle vital. De plus, ils ont imposé un traitement de densité après vernalisation. La mortalité est élevée dans les deux traitements avec le sel (43%) et le Mn (53%), comparativement aux témoins (71%). On observe une variation au niveau de la famille, de la population et du site, dans les mesures des dimensions des plantes. Il y a également des différences au niveau de la famille en réaction aux traitements du sol. Cependant, aucun des résultats n'est congru avec une adaptation locale. En général, les grandes plantes sont plus susceptibles de monter en graines, et les plantes de vieilles prairies sont moins susceptibles de le faire que les plantes des bords de route, quel que soit le traitement (dans le traitement à faible densité, 56% des plantes de bords de route ont monté à la graine, comparativement à seulement 16% pour les plantes de vieilles prairies). On constate que les traitements à haute densité conduisent à une montée en graines plus hâtive et des entrenoeuds plus longs, un résultat qui concorde avec l'hypothèse d'intolérance à l'ombre.

Scales and drivers of local adaptation in Brassica nigra (Brassicaceae) populations

“…Lowry et al (2008) showed an influence of salt spray in local adaptation among coastal and inland populations of Mimulus guttatus . However, adaptation to salinity differences may not be strong if values are below the limits of salinity stress (Rothfels et al, 2002; van Zandt et al, 2003; Pathikonda et al, 2010). Climate is often cited as the main driver of local adaptation on large geographic scales (Joshi et al, 2001; Etterson, 2004; Macel et al, 2007; Leinonen et al, 2009).…”

Competitive Interactions of Garlic Mustard (Alliaria petiolata) and Damesrocket (Hesperis matronalis)

“…This species is present in most of the United States, excluding the most southern states (USDA-NRCS 2011). Damesrocket is found in habitats similar to garlic mustard and is most common in open woods, mesic bottomlands, and roadsides (Francis et al 2009;Mitchell and Ankeny 2001;Rothfels et al 2002). Garlic mustard and damesrocket are often found growing together in the same habitats (Francis et al 2009;Murphy et al 2007).…”

The sweet smell of success: floral scent affects pollinator attraction and seed fitness in Hesperis matronalis

“…Hesperis matronalis populations are polymorphic for floral colour, with purple or white morphs, although some populations contain a pink intermediate (Dvořák 1982; Mitchell & Ankeny 2001; Rothfels et al 2002). Purple morphs have high levels of anthocyanins in their petals, whereas white morphs have little or no floral pigment.…”