Gypsy moth ( L., Lymantriinae) is a major pest of pedunculate oak () forests in Europe, but how its infections scale with foliage physiological characteristics, in particular with photosynthesis rates and emissions of volatile organic compounds has not been studied. Differently from the majority of insect herbivores, large larvae of rapidly consume leaf area, and can also bite through tough tissues, including secondary and primary leaf veins. Given the rapid and devastating feeding responses, we hypothesized that infection of leaves by leads to disproportionate scaling of leaf photosynthesis and constitutive isoprene emissions with damaged leaf area, and to less prominent enhancements of induced volatile release. Leaves with 0% (control) to 50% of leaf area removed by larvae were studied. Across this range of infection severity, all physiological characteristics were quantitatively correlated with the degree of damage, but all these traits changed disproportionately with the degree of damage. The net assimilation rate was reduced by almost 10-fold and constitutive isoprene emissions by more than 7-fold, whereas the emissions of green leaf volatiles, monoterpenes, methyl salicylate and the homoterpene (3)-4,8-dimethy-1,3,7-nonatriene scaled negatively and almost linearly with net assimilation rate through damage treatments. This study demonstrates that feeding by large insect herbivores disproportionately alters photosynthetic rate and constitutive isoprene emissions. Furthermore, the leaves have a surprisingly large capacity for enhancement of induced emissions even when foliage photosynthetic function is severely impaired.

Soil salinity is one of the best known stress factors of plants that can lead to crop yield reduction. Therefore, it is important to identify new tolerance varieties of plants that can grow on saline soils. We have studied the influence of salt on five different tomato varieties from the Western region of Romania and compared them with a commercial hybrid and found that one of them (Rudna) is a very salt-tolerant variety (up to 200 mM NaCl). The assimilation rates and stomata conductance of water vapour are affected by salinity but some of the local varieties of tomato exhibit quite good tolerance. We found that all plants under salinity stress emit (Z)-3-hexenol (a C6, green leaf volatile) and the emission of all terpenes increased in proportion to the salt concentration. The emission of three terpenes, (Z)-beta-ocimene. 2-carene and beta-phellandrene, have been quantitatively correlated with salt concentration.