The effect of mistletoe (Viscum album) on branch wood and needle anatomy of Scots pine (Pinus sylvestris)

Abstract

Mistletoes are hemi-parasitic plants growing on many tree species. They grow on the tree branches or trunk of a tree and form root-like structures called haustoria that penetrate into the tree, taking up water and mineral nutrients. Mistletoe is capable of causing a variety of effects to its hosts, including changes in wood formation and leaf development. We investigate and discuss the effects of pine mistletoe (Viscum album ssp. austriacum, Santalaceae) on branch wood and needle anatomy of Scots pine (Pinus sylvestris, Pinaceae). Parasitized and nonparasitized branches of Scots pine were sampled from host tree crowns of trees growing on the same site. Branches were taken from mid-crown facing south. They were cut at 2 cm proximal and 2 cm distal to the mistletoe on each host branch and at the corresponding position in the case of uninfected branches from the same host. The wood anatomy at proximal and distal parts and the parts at the corresponding position in the non-parasitized section was compared. The anatomy of one-year-old needles from both parasitized and non-parasitized branches was also compared. Mistletoe had significant influences on wood and needle anatomy. The major changes were the decreases in the double wall thickness, lumen area, tangential lumen area and radial lumen area of the tracheids in the wood and a decrease in vascular area in the needles. These results help to understand how mistletoe acts on its host.

Occurrence of European Mistletoe (Viscum album L.) on Forest Trees in Poland and Its Dynamics of Spread in the Period 2008–2018

“…Mistletoes contribute to increased transpiration, especially in years of water deficit, and cause marked weakening of infested trees [39,40]. According to Ozturk et al [41] mistletoe influences the anatomy of wood and needles, leading to partial or total death of the host during periods of drought [42,43], which is why it is important forest parasite. The high mortality in Scots pine stands in some places across Europe has been reported to be at least partly attributable to mistletoe infestation [24,44].…”

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 ].…”

Leaf area – sapwood area relationship in Scots pine (Pinus sylvestris L.) under mistletoe (Viscum album ssp. austriacum) infection

“…Pine mistletoe infection influences the anatomical (Ozturk et al, 2019) and morphological (Barbu, 2012;Rigling et al, 2010) characteristics of needles. The results indicated that mean needle length, width and needle area decreased significantly (p<0.05) as a result of mistletoe infection (Table 2).…”

“…Previous studies have clearly shown the effects of mistletoe on tree growth (Bilgili et al, 2020;Kanat et al, 2010), wood anatomy (Gol et al, 2018;Ozturk et al, 2019), biology (Mutlu et al, 2016b;Persoh et al, 2010), physiology (Ehleringer et al, 1986;Glatzel & Geils, 2009;Mutlu et al, 2016a) and morphology (Rigling et al, 2010) of host plants. In addition, the relationship between leaf area and sapwood area have been examined and documented in many broadleaved (Meadows & Hodges, 2002) and conifer species (Bancalari et al, 1987;Waring et al, 1982) including Scots pine (Albrektson, 1984;Berninger & Nikinmaa, 1994;Whitehead, 1978).…”

“…Drought stress exacerbated by mistletoes (Glatzel & Geils, 2009) and coupled by higher transpiration rate developing with decreasing xylem water potential in host branches lead to reduced photosynthetic rate of host (Mathiasen et al, 2008). Therefore, increased growth loss (Barbu, 2012;Bilgili et al, 2020;Bilgili et al, 2018;Ozturk et al, 2019), altered resource allocation (Tinnin & Knutson, 1980) and mortality (Rigling et al, 2010) are the typical results of mistletoe infection. In addition, mistletoe infection causes crown degradation by reducing the number of needles, needle length and width and the longevity of needles on the infected branches (Barbu, 2012;Rigling et al, 2010).…”