Mechanisms and traits associated with compensation for defoliation in Ruellia nudiflora

Abstract

A full understanding of the ecology and evolution of plant tolerance to damage requires the measurement of a diversity of traits (including multiple fitness-correlates) and underlying mechanisms. Here, we address the compensatory response to defoliation in the perennial herb Ruellia nudiflora, measure biomass allocation patterns and relate them to compensation, and address multiple mechanisms and traits that determine compensatory ability. We used maternal full-sib lines of R. nudiflora and conducted a defoliation experiment in which half the plants of each line were subjected to removal of 40% of leaf area (the other half remained undamaged). Fitness-correlated traits, physiological traits, and leaf longevity were measured during a 2-month period after defoliation. Using another set of plants, we conducted a second defoliation experiment and measured the concentration of non-structural carbohydrates to test for root-to-shoot carbon mobilization as a compensatory mechanism. R. nudiflora showed full compensation in terms of fruit output, and compensatory ability was positively correlated with investment in root biomass in the absence of damage. In addition, defoliated plants produced shorterlived leaves and had a greater concentration of starch in roots, suggesting that reduced leaf longevity and accumulation of below-ground carbon reserves act as compensatory mechanisms. By measuring multiple fitness-correlates and induced traits, we provide a comprehensive evaluation of R. nudiflora compensatory responses to herbivory.

Metabolic and enzymatic changes associated with carbon mobilization, utilization and replenishment triggered in grain amaranth (Amaranthus cruentus) in response to partial defoliation by mechanical injury or insect herbivory

“…In contrast, a drastic reduction in soluble carbon pools was detected in Agropyron bunchgrasses after severe defoliation treatments that impeded full recovery due to a limited replenishment capacity [72]. In shrubs, reduced leaf longevity and accumulation of below-ground carbon reserves allowed full compensation in terms of fruit output in defoliated R. nudiflora [73], whereas C. korshinskii relied on the preferential resource allocation to vegetative tissues for regrowth, at the cost of fruit production [74]. …”

Grain Amaranths Are Defoliation Tolerant Crop Species Capable of Utilizing Stem and Root Carbohydrate Reserves to Sustain Vegetative and Reproductive Growth after Leaf Loss

“…reversible inter-conversion between sucrose, hexoses and starch) [16], [17], [18], [19]. Recent investigations have also begun to reveal some biochemical and genetic mechanisms triggered in response to defoliation in diverse plant species [20], [21], [22], [23]. In Sesbania and Populus , physical leaf damage alters the pattern of resource allocation to various vegetative and reproductive organs [24], [25].…”

Pre‐damage biomass allocation and not invasiveness predicts tolerance to damage in seedlings of woody species in Hawaii

“…, Rivera‐Solís et al. , Barton , ). However, very little of this research has explicitly focused on seedlings (but see Myers and Kitajima , Barton , , ).…”

“…, Rivera‐Solís et al. , Barton ), increasing photosynthetic rates (Vanderklein and Reich ), and increasing growth rates (Nykänen and Koricheva ). On the other hand, constitutive mechanisms of tolerance involve traits that exist prior to damage and aid the plant's ability to manage damage after it has occurred.…”