Needle properties of host white spruce (Picea glauca [Moench] Voss) experiencing eastern dwarf mistletoe (Arceuthobium pusillum Peck) infections of differing severity

Abstract

Eastern dwarf mistletoe (Arceuthobium pusillum Peck) parasitizes the branches of white spruce (Picea glauca [Moench] Voss) and ultimately kills this host species. Previous studies of host needle physiology generally focused on trees experiencing infections of moderate severity; here, we expanded upon previous research to investigate the morphological, physiological, and biochemical properties of needles from white spruce trees experiencing the full range of infection severities. We found that the impact of parasitism on host needle parameters did not scale uniformly with infection severity. Rather, parasitism reduced host needle size distal to infection and resulted in more negative carbon isotope ratios across all infection severities. Reduced foliar nitrogen and chlorophyll content were only evident in trees with moderate or severe infection, while photosynthetic capacity was depressed in only severely infected trees. Furthermore, while some impacts were confined to infected host branches, others, such as smaller needles and reduced photosynthetic capacity, were also evident in branches showing no visible signs of infection. We conclude that symptoms of infection appearing only after infection worsened in severity or appearing in uninfected branches may in whole or in part also be manifestations of a decline in resource availability and vigor of the whole tree.

Solar‐Induced Fluorescence Does Not Track Photosynthetic Carbon Assimilation Following Induced Stomatal Closure

“…At the point of collection, leaf samples were immediately frozen in liquid nitrogen and were stored at −80 °C until processed. Leaf pigments were extracted from these stored samples in acetone according to Adams and Demmig‐Adams (1992) modified as described in de Viller et al (2017). Following extraction, leaf pigments were quantified by high‐performance liquid chromatography (HPLC) as described in de Viller et al (2017).…”

Mitigating the Mistletoe Menace: Biotechnological and Smart Management Approaches

“…), and the European mistletoes ( Viscum spp.) [ 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 ]. Mistletoes are characterized as hemiparasitic plants because of their reduced photosynthetic efficiency and the absence of a true rooting feature [ 18 , 64 ].…”

“…This is indicative of reactive oxygen species (ROS) quenching [ 53 , 61 ]. Further, a reduction in chlorophyll, foliage, and the biomass of hosts may reduce the photosynthetic potential as well as host biomass [ 52 , 58 , 59 , 62 , 122 , 123 , 124 , 125 ]. The radial growth of tree hosts has been reduced by Viscum spp.…”

Assessment of dwarf mistletoe (Arceuthobium sichuanense) infection in spruce trees by using hyperspectral data

“…Dwarf mistletoe (DM) ( Arceuthobium spp., Viscaceae) is a type of hemiparasitic plant that takes up water and nutrients from their host trees, thereby stunting host growth and causing them to be vulnerable to other diseases (Hull & Leonard, 1964; Klutsch et al., 2014; Nebeker et al., 1995; de Villier et al., 2017). A large number of forests, especially conifers (Pinaceae and Cupressaceae) in North America, Europe and Asia, have suffered heavy DM infections and tree loss (deBruyn et al., 2015; Hawksworth & Wiens, 1996; Maes et al., 2018; Noetzli et al., 2003; Xia et al., 2012).…”