Effects of Herbivory and Light Conditions on Induced Defense in Quercus crispula

Abstract

Understanding the induced resistance to herbivory in plants is important in elucidating plant life-history traits. Resistance to herbivory takes two basic forms: defense and tolerance. Induced defense plays an important role in the ecology and evolution of plant-herbivore interactions. it has become increasingly clear that induced defenses to herbivory are complex traits involving the interaction of intrinsic and extrinsic factors. In this study, we investigated the effects of herbivory and the availability of light on induced resistance in Quetcus crispula saplings, and the relation between defense and tolerance involving photosynthesis and growth. We conducted field experiments with herbivorous insects under two light conditions. As an induced defense, the leaf mass per area increased with herbivory regardless of the amount of light available, and the concentration of condensed tannin was significantly higher when light was plentiful. On the other hand, as induced tolerance, the photosynthetic rate decreased with herbivory under conditions of ample light. In conclusion, we found that both the availability of light and herbivory affected defense and tolerance in Q. crispUa. In addition, we suggest that the interaction between defense and tolerance was noticeable when much light was available because of the photosynthetic reduction caused by herbivory.

Temporal and spatial variations in leaf herbivory within a canopy of Fagus crenata

“…According to the CN balance hypothesis (Bryant et al 1983;Coley et al 1985), changes in the carbon/nutrient (such as nitrogen) ratio correlate with levels of plant defensive chemicals, such as phenolic metabolites. Some studies verified this hypothesis by documenting the indirect relationship between light and herbivores through the intermediary of phenolic plant chemicals (Larsson et al 1986;Lindroth et al 1993;Dudt and Shure 1994;Agrell et al 2000;Nabeshima et al 2001).…”

Changes in the N and P concentrations, N:P ratios, and tannin content in Casuarina equisetifolia branchlets during development and senescence

“…Total phenolics demands decreased with maturity and senescence. Tannin concentrations in plants vary in response to changes in environmental conditions such as nutrients, light, temperature, CO 2 , water availability and ozone (Chaves and Escuder 1999;Lindroth et al 2001;Nabeshima et al 2001;Koike et al 2006). The total phenolics content of young and senescent branchlets at sites 1 to 3 was significantly lower than that of young and senescent branchlets at sites 4 to 6, respectively, reflecting the changes in environmental conditions (i.e.…”

Variation in herbivory-induced responses within successively flushing Quercus serrata seedlings under different nutrient conditions

“…The concentration of TP was quantified with a spectrophotometer (U-1000, Hitachi, Tokyo, Japan), using tannic acid as a standard (Waterman and Mole 1994). Phenolic compounds such as CT and TP in leaves have been commonly used as indicators of chemical defence against herbivores (e.g., Feeny 1970;Forkner and Hunter 2000;Mutikainen et al 2000;Nabeshima et al 2001;Matsuki et al 2004;Murakami et al 2005;Koike et al 2006).…”

“…Induced response varies with environmental factors such as the availability of nutrients, light, and water (e.g., Hunter and Schultz 1995;Mutikainen et al 2000;Nabeshima et al 2001; Baraza et al 2004). The pattern of carbon allocation to the induced response depends on not only the external availability of resources but also the internal characteristics of the plant (Nykänen and Koricheva 2004).…”

“…For example, condensed tannin (CT) and total phenolics (TP) have negative effects on the growth and survival of insects (e.g., Mutikainen et al 2000;Lill and Marquis 2001;Nomura and Itioka 2002). Leaf mass per area (LMA) and leaf toughness are often used as indices of leaf physical defences (e.g., Feeny 1970;Kudo 1996;Nabeshima et al 2001) and may vary in relation to leaf chemical properties (Poorter et al 2009). Furthermore, LMA and leaf toughness are known to be important herbivory deterrents (Coley 1983;Reich et al 1991;Choong 1996;Hanley et al 2007).…”