Phenolic compounds in Norway spruce as affected by boron nutrition at the end of the growing season

Abstract

The increase in concentrations of phenolic compounds in boron (B) deficiency has been demonstrated in many herbaceous plant species, but information on woody plants is scarce. It has been suggested that accumulation of phenolic compounds plays a role in the development of cold hardiness in herbaceous plants but also that B deficiency decreases winter hardiness. Here we study the effects of B nutrition on phenolic compounds in Norway spruce (Picea abies L.) in the course of cold acclimation. Phenolic compounds were analysed in Norway spruce seedlings from three different B-fertilisation treatments in two harvests: non-acclimated and cold-acclimated seedlings. Norway spruce phenolic compounds consisted mainly of condensed tannins. During B deficiency, condensed tannins and monocoumaroyl-astragalin der. 1 increased in non-acclimated seedlings. The increase in tannins was 21%, which was nearly significant. However, the effect of B on phenolic compounds was almost absent in cold-acclimated seedlings. The condensed tannin concentration increased much more with time in the simulated autumn than due to B deficiency, and we conclude that the B effect was probably not large enough to be important for the hardening of the seedlings. The total phenolic concentrations more than doubled during the course of cold hardening suggesting that phenolics have a role in the winter hardiness in Norway spruce.

Decomposition and element concentrations of Norway spruce needle litter with differing B, N, or P status

“…In woody plants, increased concentrations of phenolics were shown in low-B Pinus echinata (Sword and Garrett 1994) and to some extent, in Olea europaea (Liakopoulos and Karabourniotis 2005) and Norway spruce (Rummukainen et al 2007, Sutinen et al 2006. On the other hand, the condensed-tannin concentrations in senesced silver birch leaves in our previous decomposition study were somewhat higher in the +B seedlings.…”

“…The condensed tannins were analyzed by using the spectrophotometric acid-butanol assay (Porter et al 1986, Rummukainen et al 2007), 2 mg subsamples as three repetitions. Tannin extracted from Norway spruce needles was used as standard (Rummukainen et al 2007).…”

“…In earlier studies on Norway spruce seedlings, tannins have increased slightly in low-B treatments. Seedlings with low B status had higher concentrations of condensed tannins and their precursor, (+)-catechin, in fully developed needles (Rummukainen et al 2007), as well as more tanniferous cells in primordial shoots (Sutinen et al 2007). These effects were not very large, and probably would not make a difference for the health of the trees, as the increase was less than the change in tannin concentration due to seasonal variation (Rummukainen et al 2007).…”

“…Seedlings with low B status had higher concentrations of condensed tannins and their precursor, (+)-catechin, in fully developed needles (Rummukainen et al 2007), as well as more tanniferous cells in primordial shoots (Sutinen et al 2007). These effects were not very large, and probably would not make a difference for the health of the trees, as the increase was less than the change in tannin concentration due to seasonal variation (Rummukainen et al 2007). Large increases in numbers of tannin-containing cells in developing needles were found in Norway spruce trees that were already deformed because of B deficiency in the field (Sutinen et al 2006).…”

Boron Fertilization Enhances the Induced Defense of Silver Birch

“…This is contrary to the results of earlier studies conducted with herbaceous species (Ruiz et al, 1998;Cakmak and Römheld, 1997;CamachoCristóbal et al, 2002). Similarly, in a study of the conifer, Norway spruce, B deficiency had a minor effect on phenolic contents; the level of condensed tannins (CTs) and monocoumaroyl-astragallin derivative were slightly induced in the B deficient trees (Rummukainen et al, 2007). Olive trees growing in the field with visible B deficiency symptoms also did not accumulate phenolics in their leaves, whereas potted B deficient olive seedlings cultivated in the growth chamber did (Liakopoulos and Karabourniotis, 2005).…”