Effects of plant phenology, nutrients and herbivory on growth and defensive chemistry of plantain, Plantago lanceolata

Abstract

2000. Effects of plant phenology, nutrients and herbivory on growth and defensive chemistry of plantain, Plantago lanceolata. -Oikos 88: 371 -379.To assess the combined effect of herbivory, nutrient availability and plant phenology on plant mass and defensive chemistry, we conducted a field experiment with plantain (Plantago lanceolata: Plantaginaceae) using three levels of herbivory, three levels of fertilizer and two harvest dates. Shoot mass of the no-herbivory plants showed a nonlinear response to increased fertilizer such that mass with high fertilizer was no greater than that with low fertilizer. In contrast, shoot mass of the low-herbivory plants (12% damage) was not influenced by fertilizer, but for high-herbivory plants (23% damage), there was a positive linear response to increased fertilizer. Increasing nutrient levels caused a decrease in iridoid glycoside concentration. Herbivory did not induce higher iridoid glycoside concentration in leaves of any age. But increasing herbivory resulted in a decrease in the concentration of catalpol in new leaves. Another experiment assessed how leaf age and plant age affected plant defensive chemistry. Total iridoid glycosides increased over 5 weeks, but catalpol only increased in new leaves. Overall, the order of importance in determining variation in iridoid glycoside concentration was plant phenology, nutrient availability and, to a much lesser extent, herbivory.

Arbuscular mycorrhizal fungal species suppress inducible plant responses and alter defensive strategies following herbivory

“…High constitutive levels of iridoid glycosides in plants associated with S. calospora may be a result of early induction by the infection of a fungus that does not benefit growth in the long term, resulting in a stress response to limited resources (Bennett and Bever 2007;Bever 2002a), a strategy to counter herbivory in a nonoptimal environment, or a response to increased nitrogen in plant tissues. Although increased nutrients result in decreased concentrations of iridoid glycosides in P. lanceolata tissues (Jarzomski et al 2000), nutrient concentrations are not likely responsible for the increased iridoid glycosides in plants associated with S. calospora because they had an intermediate amount of nitrogen in tissues (Fig. 3).…”

“…In previous studies of P. lanceolata inducible responses (Adler et al 1995;Bowers and Stamp 1993;Darrow and Bowers 1999;Fuchs and Bowers 2004;Jarzomski et al 2000;Stamp and Bowers 1994 there was often greater induction of iridoid glycosides in plants likely lacking AM fungi (e.g., in greenhouses) versus environments where AM fungi are likely present (e.g., field settings). While many factors may be responsible for the differences in induction observed between greenhouse and field studies, this result is consistent with our observation that the presence of multiple AM fungal species reduces the induced response in P. lanceolata, and may suggest that in environments where AM fungi are common, defense strategies other than induced chemical responses are likely to be important.…”

Untargeted metabolic profiling reveals geography as the strongest predictor of metabolic phenotypes of a cosmopolitan weed

“…Past experiments on target metabolite induction in Plantago have found induction to be short‐lived and therefore difficult to detect (i.e., Bowers & Stamp, 1993; Darrow & Bowers, 1999; Fuchs & Bowers, 2004). The timing of the metabolomic screening in our study, as well as in other studies where no or insignificant differences were found (i.e., Jarzomski et al., 2000; Stamp & Bowers, 1996; Sutter & Muller, 2011), could limit detection of induced metabolites. Additional work should aim to investigate important factors such as the time and type of herbivore damage under in situ conditions.…”

Galling Insect Community Associated with Copaifera langsdorffii (Fabaceae): The Role of Inter- and Intra-annual Host Plant Phenology

“…Plant phenology vary among and within years and can affect the insect herbivores directly by synchronism between specifi c phenological stages and population dynamics of insects (How et al 1993 ;Fox et al 1997 ;Vitou et al 2008 ) or indirectly, by determining the quality of plant tissues for herbivores (Jarzomski et al 2000 ;Russel and Louda 2004 ;Coyle et al 2010 ). Moreover, the supra annual phenology also produces variation in resource for herbivores between years of high and low plant reproduction (Obeso 2002 ;Forister 2005 ;Fagundes et al 2013 ).…”