The effect of dwarf mistletoe on starch concentrations in the twigs and needles of lodgepole pine

Abstract

The effect of Arceuthobiumamericanum on starch concentrations in the needles and twigs of Pinuscontorta was analyzed at two study sites. We found that the starch concentration of needles from systemically infected branches was significantly higher than that of those from locally infected branches and that the concentration in needles from locally infected branches was significantly higher than that of those from uninfected branches. We also found that the starch concentration of twigs from locally infected branches was significantly higher than that of twigs from uninfected branches. Our results collectively suggest a trend in starch concentrations form 1% of dry mass or less in needles from uninfected branches to 1–2% in needles from branches with local infections to greater than 2% in needles from systemically infected branches.

Impact of eastern dwarf mistletoe (Arceuthobium pusillum) on host white spruce (Picea glauca) development, growth and performance across multiple scales

“…Thus, the combined effects of parasite‐associated alterations to host hormone signaling could delay the senescence of IBs. This could favor the delivery of whole‐tree resources to IBs, at the expense of UBs (see Clark and Bonga, , Broshot and Tinnin , Wanner and Tinnin ). Microbial symbionts and pathogens, including Crinipellis perniciosa , the causative agent of witches' brooms in Theobroma cacao , are known to affect host resource delivery by producing CKs (Greene , Orchard et al , Bruce et al ).…”

Mistletoes: Pathology, Systematics, Ecology, and Management

“…5C), alter host phytohormone balance, resulting in the formation of dense masses of branches called witches'-brooms (126,159,187). Branches from witches'-brooms exhibit features atypical of uninfected host tissue such as: increased longevity (222); elimination or reduction of seed and cone production (24,116); increased branch elongation on some hosts (83,209); increased biomass compared with uninfected branches of the same age (209); and decreased number, length, and mass of needles (28,29,175). While witches'-brooms are the most easily observed symptom of dwarf mistletoe infection and serve as large nutrient sinks that contribute to the decline of host vigor and growth (136), they also appear to have positive effects in an ecological context (see below).…”

Parasitic plants: parallels and contrasts with herbivores

“…Cuscuta (dodder) species alter host physiology by acting as a stronger sink for photosynthate than any host organ (Ihl et al 1984;De Bock and Fer 1992;Parker and Riches 1993). Similarly, although mistletoe leaf area is generally several orders of magnitude lower than that of their hosts, they reduce host growth, partly by diversion of resources (Hull and Leonard 1964;Miller and Tocher 1975;Schulze and Ehleringer 1984;Ehleringer et al 1985Ehleringer et al , 1986bMarshall and Ehleringer 1990;Rey et al 1991;Marshall et al 1994), but also by parasite-induced physiological responses that result in abnormal growth patterns and altered resource allocation of the host (Brochot and Tinnin 1986;Wanner and Tinnin 1986;Ihl et al 1987). Parasitic plants alter the morphology and physiology of their hosts by stimulating production of host growth hormones or by infusing hormones directly into hosts (Drennan and El-Hiweris 1979;Knutson 1979;Livingston et al 1984).…”