Abies Seedlings Research Articles

Protein Polymorphism between 2 Picea abies Populations Revealed by 2-Dimensional Gel Electrophoresis and Tandem Mass Spectrometry

In species with high gene flow and consequent low interpopulation differentiation over wide geographic ranges, differential gene expression along ecological gradients often reveals adaptive significance. We investigated potential differences in protein expression between Picea abies ecotypes adapted to contrasting altitude conditions. Protein expression patterns were compared between needles and roots of 2-month-old P. abies seedlings by means of 2-dimensional electrophoresis. Proteins exhibiting differential expression between the 2 ecotypes were analyzed by tandem mass spectrometry. A total of 19 proteins exhibited qualitative or quantitative polymorphism between the 2 populations. These proteins exhibited organ-specific expression, and the level of interpopulation protein polymorphism was organ dependent. Among differentially expressed proteins, we identified proteins involved in photosynthesis, photorespiration, root tracheary element differentiation, and transmitochondrial membrane transport. Our results show that P. abies seedlings from locally adapted ecotypes exhibit consistent differences in protein expression. The expression polymorphism of some of these proteins has potential adaptive significance.

Рост и продуктивность сеянцев ели европейской разных сроков посева

Рост и продуктивность сеянцев ели европейской разных сроков посева

Frost hardiness of nutrient-loaded two-year-old Picea abies seedlings in autumn and at the end of freezer storage

The effects of nutrient loading (NLOAD) on the frost hardening and dehardening of Picea abies (L.) Karst. seedlings were investigated under nursery conditions. Before NLOAD, second-year container seedlings were either short-day (SD) treated for 3 weeks in July or left for the natural photoperiod (CO). By mid-September, after 5 weeks of NLOAD, the fertilization of three foliar nutrient concentration levels (low = L-SD, medium = M-SD, and high = H-SD) for the SD-treated seedlings and one (medium = M-CO) for the CO-seedlings was completed. The NLOAD resulted in foliar nitrogen concentration 10.6, 16.1, 22.3, and 17.5 g kg−1 for L-SD, M-SD, H-SD and M-CO seedlings, respectively. The NLOAD had no effects on the morphology or dry mass variables of the seedlings, while SD-treatment reduced the dry mass of shoots, but not that of roots. The frost hardiness (FH) of different batches of the seedlings was assessed by the visual scoring of damage in their needles, stems and buds after their controlled exposure to freezing during frost hardening and dehardening. The low nutrient concentration in the SD-treated seedlings (L-SD seedlings) resulted in poor FH, to an even lower extent than that of the M-CO seedlings. The NLOAD did not affect the dehardening of the seedlings at the end of the freezer storage in the following spring.

Organic acids in root exudates from Picea abies seedlings influenced by mycorrhiza and aluminum

AbstractOrganic acid anions exuded from roots of Picea abies (Norway spruce) seedlings grown on glass beads in the presence and absence of mycorrhiza (Laccaria bicolor) and aluminum (Al) at pH 3.9 were measured. We wanted to test if the roots exuded more organic acid anions when exposed to Al and if mycorrhization influenced the exudation. Oxalate was exuded in far higher amounts than any other organic acid anion, with a maximum rate of 1.7 nmol (mg root DW)–1 d–1. Mycorrhizal roots exuded significantly more oxalate than nonmycorrhizal roots. The presence of Al did not enhance oxalate exudation. We conclude that the oxalate exuded constitutively by Picea abies/Laccaria bicolor may lead to rhizosphere oxalate concentrations that are relevant for Al resistance.

Short-day treatment enhances root egress of summer-planted Picea abies seedlings under dry conditions

Second year Norway spruce [Picea abies (L.) Karst.] container seedlings, short-day (SD) treated for 3 weeks in July, were exposed together with untreated control seedlings (Co) to three different drought treatments for 5 weeks after planting in early August. The treatments were: (1) regular watering (0 week drought); (2) 2 weeks of drought and 3 weeks of watering; and (3) no watering (5 week drought). No difference was found in the vigour and shoot xylem water potential between the SD-treated and the Co seedlings after the drought treatments. The root growth decreased less for the SD seedlings than for the Co seedlings along with the increase in the length of the drought period.

Emergence and seasonal mortality of naturally regenerated Picea abies seedlings: impact of overstory density and two site preparation methods

Manipulation of the canopy cover and site preparation are the most important silvicultural measures to enhance the conditions for natural regeneration of Norway spruce (Picea abies (L.) Karst.). During the early regeneration phase however, seedling mortality may be high, so it is important to study how different combinations of stand-level treatments and site preparation methods affect seedling establishment. We studied emergence, 1st winter and 2nd summer mortality for naturally regenerated spruce seedlings in a field experiment that combined four harvest treatments (shelterwoods of high (SH), medium (SM) and low (SL) residual basal area, and a 50 × 50 m clear-cut (CC)) and two site preparation methods (patch scarification and inverting). The CC had significantly fewer seedlings the 1st fall than the SL and SH (p = 0.0377), and in all harvest treatments, fewer seedlings emerged in inverted than in patch scarified spots (p = 0.0351). Mortality was also lower with patch scarification than inverting (1st winter: p = 0.0565, 2nd summer: p = 0.0377), but was not affected by harvest treatment (1st winter: p = 0.9211, 2nd summer: p = 0.1896). On average, mortality from 1st to 2nd fall reached 38% and 27% after inverting and patch scarification, respectively. First winter mortality accounted for approximately two thirds of the accumulated mortality, regardless of the harvest treatment and site preparation method.

Temperature‐Respiration Relationships Differ in Mycorrhizal and Non‐Mycorrhizal Root Systems of Picea abies (L.) Karst.

Root respiration has been shown to increase with temperature, but less is known about how this relationship is affected by the fungal partner in mycorrhizal root systems. In order to test respiratory temperature dependence, in particular Q (10) of mycorrhizal and non-mycorrhizal root systems, seedlings of PICEA ABIES (L.) Karst. (Norway spruce) were inoculated with the ectomycorrhizal fungus PILODERMA CROCEUM (Eriksson and Hjortstam, SR430; synonym: PILODERMA FALLAX: [Libert] Stalpers) and planted in soil respiration cuvettes (mycocosms). Temperature dependence of hyphal respiration in sterile cultures was determined and compared with respiration of mycorrhizal roots. Respiration rates of mycorrhizal and non-mycorrhizal root systems as well as sterile cultures were sensitive to temperature. Q (10) of mycorrhizal root systems of 3.0 +/- 0.1 was significantly higher than that of non-mycorrhizal systems (2.5 +/- 0.2). Q (10) of P. CROCEUM in sterile cultures (older than 2 months) was similar to that of mycorrhizal root systems, suggesting that mycorrhizae may have a large influence on the temperature sensitivity of roots in spite of their small biomass. Our results stress the importance of considering mycorrhization when modeling the temperature sensitivity of spruce roots.

Identification of quantitative trait loci affecting virulence in the basidiomycete Heterobasidion annosum s.l.

Identification of virulence factors of phytopathogens is important for the fundamental understanding of infection and disease progress in plants and for the development of control strategies. We have identified quantitative trait loci (QTL) for virulence on 1-year-old Pinus sylvestris and 2-year-old Picea abies seedlings and positioned them on a genetic linkage map of the necrotrophic phytopathogen Heterobasidion annosum sensu lato (s.l.), a major root rot pathogen on conifers. The virulence of 102 progeny isolates was analysed using two measurements: lesion lengths and fungal growth in sapwood from a cambial infection site. We found negative virulence effects of hybridization although this was contradicted on a winter-hardened spruce. On P. abies, both measurements identified several partially overlapping QTLs on linkage group (LG) 15 of significant logarithm of odds (LOD) values ranging from 2.31 to 3.85. On P. sylvestris, the lesion length measurement also identified a QTL (LOD 3.09) on LG 15. Moreover, QTLs on two separate smaller LGs, with peak LOD values of 2.78 and 4.58 were identified for fungal sapwood growth and lesion lengths, respectively. The QTL probably represent loci important for specific as well as general aspects of virulence on P. sylvestris and P. abies.

Post-transplant root and shoot development inAbies nordmannianaSpach. seedlings after whorl bud and branch pruning

After lifting in a nursery, 3-year-old seedlings ofAbies nordmanniana were treated for improvement in new leader growth after transplanting. The treatments were: (A) whorl (subapical) buds, lateral buds at the stem and whorl branch tips removed; (B) as (A), but with whorl branches removed at their junction to the stem; and (C) untreated control seedlings. After transplanting in April, plant samples were lifted in June, July and September to determine the effect of treatments on root and shoot development. Root length and number of root tips were determined by scanning and computed image analysis. Height, dry weight of shoot and root and ratio between these were determined. Removal of whorl and lateral buds and whorl branch tips had a negative effect on root and shoot growth after transplanting. Root length, number of root tips and shoot dry weight were reduced, but by September equaled the untreated control seedlings. Removal of whorl branches caused a significant reduction in both root length and shoot dry weight compared to untreated control seedlings. root length / root:shoot / root tip scanning

Methyl jasmonate treatment of mature Norway spruce (Picea abies) trees increases the accumulation of terpenoid resin components and protects against infection by Ceratocystis polonica, a bark beetle-associated fungus

When conifers such as Picea abies Karst. (Norway spruce) are attacked by insects or pathogens, they often respond by producing increased quantities of terpenoid oleoresin. This response can be mimicked in young P. abies seedlings by treatment with methyl jasmonate (MJ). In this study, we determined the effects of MJ on terpenoids and other chemical defenses of mature P. abies, and investigated whether this treatment protected trees against attack by the blue-stain fungus Ceratocystis polonica (Siem.) C. Moreau, the most important fungal associate of the spruce bark beetle Ips typographus L. Methyl jasmonate treatment induced the formation of traumatic resin ducts in the developing xylem, enhanced resin flow and stimulated increased accumulation of monoterpenes, sesquiterpenes and diterpene resin acids. However, only minor changes were detected in terpene composition in response to MJ treatment and no changes in soluble phenolic concentration were measured. There was much variability in the timing and degree of response to MJ among clones. The observed chemical and anatomical changes in response to MJ treatment were correlated with increased resistance to C. polonica, suggesting that terpenoid oleoresin may function in defense against this pathogen.

Multiple leaders caused by the tarnished plant bug (Lygus rugulipennis) in Picea abies seedlings

Feeding by the tarnished plant bug (Lygus rugulipennis Popp.) has caused severe damage in Norwegian nurseries. Large quantities of seedlings have been removed after sorting. The life cycle of the insect has been well studied and documented. This study was a first attempt to investigate how the seedlings develop after the insect attacks. The first visible sign of damage is the development of multiple terminal buds. Two-year-old containerized seedlings were planted and followed for 4 years. Before planting, the seedlings were sorted into three damage classes: 0, undamaged; I, moderately damaged, up to 10 fully developed buds; and II, severely damaged, 10–20 small buds and no dominant apical bud. The damaged seedlings were somewhat shorter at planting but this difference disappeared with time. The seedlings in the two damage classes differed in their development of multiple shoots. At the end of the 4 year period about 50% of the seedlings in class II and about 20% from class I still had multiple leaders, or lateral stems or side branches that would probably produce spike knots in the future. The sorting routine currently used at the nursery was found to reduce the problem to an acceptable level for seedlings that were planted in the forest.

Chemical and biological characterization of dissolved organic matter from silver fir and beech forest soils

Despite a growing attention to the dissolved organic matter (DOM) in terrestrial ecosystems and evidence of the fact that vegetation affects the quality of both undissolved and dissolved organic matter in soil, the role of DOM as a biological indicator is still poorly understood. In this work, the fertility of 59 sites, divided into eight key alliances of the order Fagetalia sylvaticae Pawl., was studied considering chemical and biological parameters such as soil DOM, hormone-like activity, low-molecular-weight (LMW) aliphatic and phenolic acids, and floristic data. Both non-parametric tests and principal component analysis (PCA) revealed differences between silver fir and beech forests and within each type of forest. There were also differences between neutrophilous and acidophilous types. What’s more, PCA reveals the dominance of the auxin (IAA)-like activity, and of some phenolic acids in distinguishing the acidophilous beeches (ACI) form the other types, whereas the gibberellin (GA)-like activity is more relevant in neutrophilous conditions such as thermophilous (THE) and mesophilous (MESO) beeches and montane (MO), high montane (HMA), high montane (HMC) silver fir forests. The GA-like activity is also related to the succinic, fumaric, malonic, and l-malic acids in the MO, HMA and HMC silver fir forests. Moreover, the role of LMW aliphatic acids in mobilizing the hormone-like activity, which improves forest growth, is stressed. The growth of seedlings of Picea abies was influenced by the phenolic acid content. At concentrations between 1 and 100 μM, phenylacetic and protocatechuic acids inhibited root growth to the same extent as indoleacetic acid, while p-hydroxybenzoic acid had a stimulating effect comparable to that of gibberellic acid. The aliphatic and phenolic acids appear to be related to plant strategies that influence soil fertility affecting plant growth through rhizodeposition. The role of LMW aliphatic and phenolic acids as molecular markers of ecosystem function is noted.

Fungi in decayed roots of conifer seedlings in forest nurseries, afforested clear‐cuts and abandoned farmland

Fungi colonizing decayed roots of Pinus sylvestris and Picea abies seedlings were assessed by pure‐culture isolation and direct sequencing of DNA extracted from roots collected from three environments: bare‐root forest nurseries; afforested clear‐cuts; and abandoned farmland. Pure‐culture isolation from 1500 roots collected from 480 seedlings (240 of each tree species) yielded 1110 isolates which, based on mycelial morphology and ITS rDNA sequencing, were found to represent 87 distinct taxa. Direct ITS rDNA sequencing from decayed sections of 140 roots (70 of each tree species) yielded 160 sequences representing 58 taxa. Direct sequencing revealed a significantly higher fungal diversity per root segment than pure‐culture isolation. Overall, a total of 131 taxa were found, 92 of which (70·2%) were identified at least to genus level. Only 14 taxa (10·7%) were detected by both methods, while 73 (55·7%) were detected exclusively by isolation and 44 (33·6%), exclusively by sequencing. The pathogens Fusarium oxysporum (25·6%) and Nectria radicicola (14·9%) were the most common isolates. In contrast, direct sequencing most frequently detected endophyte Phialocephala fortinii (33·1%) and Chalara sp. NS234A2 (10·0%). There were no significant differences in species richness between roots from the different environments, but there was a marked effect on fungal community structure. The results demonstrate that different fungi inhabit decayed roots of conifer seedlings in different environments, and that pure‐culture isolation and direct sequencing are complementary methods that are both necessary for a complete description of the fungal communities colonizing diseased conifer roots.

Morning, noon, or afternoon: does timing of direct radiation influence the growth of Picea abies seedlings in mountain forests?

Nous avons etudie si le moment du rayonnement direct pendant la journee influencait la croissance des semis de Picea abies. Cette recherche a ete realisee dans un site experimental en pente expose au nord dans la zone subalpine des Alpes suisses. Des parois verticales ont ete erigees afin d'exposer des semis de P. abies de trois ans au rayonnement direct a differents moments de la journee (le matin, a midi, l'apres-midi), et au rayonnement diffus seulement, et ceci pendant deux periodes de vegetation. Les microstations formees par les traitements d'exposition a la lumiere devaient ressembler a des microstations en ouvertures diversement orientees en foret. Bien que ces traitements aient modifie l'evolution de la temperature du sol au cours de la journee, ils n'ont influence ni la temperature moyenne du sol pendant la periode de vegetation ni la frequence des temperatures du sol superieures a 10 °C, un niveau suppose etre particulierement benefique a la croissance des semis. Le rayonnement direct n'a pas modifie la biomasse finale des semis, mais la biomasse des semis qui ne recevaient que du rayonnement diffus etait plus petite. Il resulte de cette etude que l'orientation des ouvertures en fente dans des forets subalpines n'est pas susceptible d'influencer la croissance des semis de P. abies.

Species-specific acclimation to strong shade modifies susceptibility of conifers to photoinhibition

Photoinhibitory processes in the photosynthetic apparatus of the seedlings of Abies alba (Mill.), Picea abies (Karst.), and Pinus mugo (Turra) growing under strong shade (5 % of full solar irradiance) or full irradiance conditions were investigated in winter and spring using chlorophyll a fluorescence techniques. The extent of photoinhibition in needles as indicated by a decrease in maximum quantum yield of PS II photochemistry (Fv/Fm) depended on species, air temperature and acclimation to the light environment. Unexpectedly, shade-tolerant Abies alba was less affected by low-temperature photoinhibition compared to the other species. Fv/Fm recovered with increasing air temperature. During winter, the seedlings of Picea abies growing in shade showed higher Fv/Fm than those from full light. Non-photochemical quenching of fluorescence (NPQ) measured at the same levels of actinic light was higher in needles acclimated to full light except for Abies alba in February. Photosynthetic performance in term of ETR (apparent electron transfer rate) was also higher in full light-acclimated needles. In April, at ambient temperature, recovery of PS II efficiency from the stress induced by illumination with saturating light was faster in the needles of Picea abies than in those of Abies alba. The shade-acclimated needles of Abies alba and Picea abies showed greater down-regulation of PS II induced by high light stress.

Effect of drought stress on chlorophyll a fluorescence and electrical admittance of shoots in Norway spruce seedlings

Effects of mild and severe soil drought on the water status of needles, chlorophyll a fluorescence, shoot electrical admittance, and concentrations of photosynthetic pigments in needles of seedlings of Picea abies (L.) Karst. were examined under controlled greenhouse conditions. Drought stress reduced shoot admittance linearly with a decrease in shoot water potential (Ψw) and increase in water deficit (WD) and led to a decrease in concentrations of chlorophyll a, b and carotenoids. Severe water stress (shoot Ψw=−2.4 MPa) had a negative effect on chlorophyll a fluorescence parameters including PSII activity (Fv/Fm), and the vitality index (Rfd). Variations in these parameters suggest an inhibition of the photosynthetic electron transport in spruce needles. Water stress led to a decrease in the mobility of electrolytes in tissues, which was reflected by decreased shoot electrical admittance. After re-watering for 21 days the WD in needles decreased and the shoot water potential increased. In the re-watered plants, the chloroplast function was restored and chlorophyll a fluorescence returned to a similar level as in the control plants. This improved hydraulic adjustment in the seedlings triggered a positive effect on ion flow in the tissues and increased shoot electrical admittance. We conclude that the shoot electrical admittance and photosynthetic electron transport in leaves are closely linked to changes in water status and their decrease is among the initial responses of seedlings to water stress.

Insecticides sprayed on seedlings of Picea abies during active growth: Damage to plants and effect on pine weevils in bioassay

In Finland, the planting period for Norway spruce [Picea abies (L.) Karst.] has lengthened from spring to summer so that seedlings are also planted during the active growing stage, not only when dormant. On many regeneration sites, there is a high risk of damage by the large pine weevil, Hylobius abietis L., and insecticide treatments are needed to protect seedlings against these weevils. However, all currently available insecticides have been tested and accepted for use only on seedlings that are not growing actively. In this study, actively growing Norway spruce seedlings were treated with three insecticides in mid-June, when the current year's shoot was about 7 cm and unlignified. At this stage of growth, GORI 920® (permethrin) damaged needles and reduced the following year's height growth. Decis Tab® (deltamethrin) and Karate Zeon® (lambda-cyhalothrin) caused no side-effects. All three products were also more or less effective in preventing feeding of pine weevils 1 yr after the treatments. Further studies are needed to investigate the possible harmful effects of insecticides in different stages of growth during the growing season.

Survival, growth and needle element concentrations of Picea abies (L.) Karst. seedlings after brash removal in a previously N fertilized stand

Export of nutrients after whole-tree harvest (WTH), i.e. harvesting nearly all of the aboveground parts of the trees, may affect the long-term sustainability of forest production. The aim of this study was to investigate the effects on planted Picea abies (L.) Karst. seedlings (in terms of survival, growth, and elemental concentrations in needles) of brash removal at final felling on unfertilized control plots, and others that had been fertilized with 4 × 120–600 = 480–2400 kg N ha −1 in the form of urea, prior to harvest. During the first six growing seasons after planting, the survival rate of originally planted seedlings was not affected by the brash removal. For replacement seedlings, the survival rate during the first 5 years after planting tended to be somewhat higher on plots where the brash was removed compared with plots where the brash was left on site, as in a conventional harvest (CH). The survival was not affected by the pre-harvest N fertilization. The height development of the seedlings was not influenced by either of the two treatments. However, the mean volume per seedling tended to be larger in the WTH than in the CH-plots for replacement seedlings, but not for originally planted seedlings. Needles from seedlings in the CH-plots showed significantly higher concentrations of N, S, B and Cu compared with needles from seedlings in the WTH-plots. The previous N fertilization did not influence the element concentrations. The results indicate that survival and early growth of planted P. abies seedlings were marginally affected after WTH compared with CH on the studied site, where the supply of plant-available N was indicated to not be limiting for tree growth.

Growth, allocation and tissue chemistry of Picea abies seedlings affected by nutrient supply during the second growing season.

One-year-old Norway spruce (Picea abies (L.) Karst.) seedlings were grown hydroponically in a growth chamber to investigate the effects of low and high nutrient availability (LN; 0.25 mM N and HN; 2.50 mM N) on growth, biomass allocation and chemical composition of needles, stem and roots during the second growing season. Climatic conditions in the growth chamber simulated the mean growing season from May to early October in Flakaliden, northern Sweden. In the latter half of the growing season, biomass allocation changed in response to nutrient availability: increased root growth and decreased shoot growth led to higher root/shoot ratios in LN seedlings than in HN seedlings. At high nutrient availability, total biomass, especially stem biomass, increased, as did total nonstructural carbohydrate and nitrogen contents per seedling. Responses of stem chemistry to nutrient addition differed from those of adult trees of the same provenance. In HN seedlings, concentrations of alpha-cellulose, hemicellulose and lignin decreased in the secondary xylem. Our results illustrate the significance of retranslocation of stored nutrients to support new growth early in the season when root growth and nutrient uptake are still low. We conclude that nutrient availability alters allocation patterns, thereby influencing the success of 2-year-old Norway spruce seedlings at forest planting sites.

Substrate-associated seedling recruitment and establishment of major conifer species in an old-growth subalpine forest in central Japan

In this study, we investigated substrate-associated seedling recruitment and establishment of major conifer species, Abies mariesii, Abies veitchii, Picea jezoensis var. hondoensis and Tsuga diversifolia, in a subalpine forest in central Japan. For all species, the abundance of currently germinated seedlings significantly reflected seed rain abundance and did not differ between substrate types, suggesting that seedlings emerge where seeds fall and that there is little difference in germination rate between substrates. This is probably because moisture-retention capacity, which is important for seedling germination, is usually adequate at the time of germination irrespective of substrate type. However, for all species, the survival rate of current seedlings was higher on woody debris (WD) than soil, and as a result older seedlings (≥1-year-old) were more abundant on WD. It is probable that several agents such as summer drought and pathogenic fungi reduced the survivorship of current seedlings on soil. Although mortality agents influence the survival of not only current seedlings but also older ones, results suggest that a relatively drastic change occurs from the current to 1-year-old seedling stage. Consequently, WD functions as safe sites, especially for first-year establishment, and thereby older seedlings are preferentially established on WD. Additionally, results suggest that the properties of WD have a significant effect on seedling survival and establishment, since older seedling densities seemed to differ among WD decay classes. Furthermore, compared to Picea and Tsuga, a relatively large proportion of 1-year-old Abies seedlings were maintained on soil due to their higher survival rate on soil substrates. This results from the large seed/seedling size of Abies, which probably provides several advantages at the time of first-year establishment. Thus, the events determining variations in safe sites for the seedlings of each conifer species in this subalpine forest specifically occur at the time of first-year establishment following germination.