Ludwigia hexapetala and L. grandiflora are recent, aggressive invaders of freshwater wetlands in California. To assess the relative role of sexual versus clonal reproduction in invasive spread, we used AFLP markers to genotype 794 ramets of L. hexapetala sampled from 27 populations in three watersheds of California, and 150 ramets of L. grandiflora from five populations in a fourth watershed. W...

Clonal plants producing both clumping and spreading ramets can adjust their growth forms in response to resource heterogeneity or environmental stress. They might produce clumping ramets to retain favorable patches, or produce spreading ramets to escape from stress-affected patches. This study aimed to investigate the rarely reported concurrent effects of sediment accretion and nutrient enrichm...

After local herbivory, plants can activate defense traits both at the damaged site and in undamaged plant parts such as in connected ramets of clonal plants. Since defense induction has costs, a mismatch in time and space between defense activation and herbivore feeding might result in negative consequences for plant fitness. A short time lag between attack and defense activation is important t...

BACKGROUND AND AIMS Many plants reproduce both clonally and sexually, and the balance between the two modes of reproduction will vary among populations. Clonal reproduction was characterized in three populations of the wild strawberry, Fragaria virginiana, to determine the extent that reproductive mode varied locally between sites. The study sites were fragmented woodlands in Cook County, Illin...

A main tenet of sex-allocation theory is that environmental stress should lead to increased maleness because reproducing through pollen is generally cheaper than producing fruits and seeds. Though this prediction has held for many species, it has been little tested for gynomonoecious plants, in which individuals produce both female and perfect flowers. We exposed eight ramets of each of 22 gene...

The effect of local hydrogen concentration on nanoindentation-induced phase transformations has been investigated in ion-implanted amorphous silicon a-Si . Elevated concentrations of H ranging from 5 1018 to 5 1020 cm−3, over the depth of indentation-induced phase transformed zones have been formed in the a-Si by H ion-implantation. Indentation has been performed under conditions that result in...

The responses of plants to recurrent stress may differ from their a single event. In this study, we investigated whether clonal can remember past environments. Parental ramets Glechoma longituba (Nakai) Kuprian were exposed UV-B treatments either once or repeatedly (20 and 40 repetitions). Differences in DNA methylation levels growth parameters among parents, offspring genets analysed. Our resu...

Budbreak of individual ramets of clonal Gambel oak (Quercus gambelii: Fagaceae) was advanced experimentally to test the effects of altered timing of budbreak and hence, leaf age, on patterns of folivory. Early-season folivory by leaf-chewing insects was significantly greater on younger leaves of control ramets than older leaves of experimental ramets. However, differences in cumulative folivory...