Mechanical bending stress applied during dormancy and (or) growth stimulates stem diameter growth of Scots pine seedlings

1995 ◽  
Vol 25 (6) ◽  
pp. 886-890 ◽  
Author(s):  
Erik Valinger ◽  
Lars Lundqvist ◽  
Björn Sundberg
Keyword(s):  
Scots Pine ◽  
Growth Response ◽  
Growth Period ◽  
Winter Period ◽  
Bending Stress ◽  
Growth Phases ◽  
Stem Form ◽  
Dormant Period ◽  
Pine Seedlings ◽  
Mechanical Bending

Five-year-old Scots pine (Pinus sylvestris L.) seedlings were given the following treatments: unbent control; bending during dormant period (frozen seedlings); bending during growth period; bending during both dormant and growth periods. Bending was executed manually to 30° from the vertical in four perpendicular directions. This was repeated on 9 occasions for the dormancy and growth treatments and on 18 occasions for the combined dormancy and growth treatment. There was increased xylem and bark production at the point of bending for all treatments. Growth response to bending during growth was of a higher magnitude than the response following bending during dormancy. Moreover, there was a tendency for bending during both dormant and growth phases to increase radial growth of xylem and bark more than the sum of each treatment administered singly. It is concluded that mechanical stress by wind and snow imposed during the dormant winter period could influence stem form.

Effects of magnesium deficiency on needle ultrastructure and growth of Scots pine seedlings

1995 ◽  
Vol 25 (11) ◽  
pp. 1806-1814 ◽  
Author(s):  
Virpi Palomäki
Keyword(s):  
Scots Pine ◽  
Magnesium Deficiency ◽  
Control Level ◽  
Growth Period ◽  
Mesophyll Cells ◽  
Mg Deficiency ◽  
Growing Period ◽  
Pine Seedlings ◽  
Second Growth ◽  
Mg Content

Effects of magnesium (Mg) deficiency on 3-year-old Scots pine (Pinussylvestris L.) seedlings were studied during a field experiment extending over two growth periods. Seedlings were grown in quartz sand in 7.5-L pots watered with nutrient solutions in which the Mg content was reduced to 30 and 0% of the control level (15 mg/L in the first and 3 mg/L in the second growth period). During the first growing period the Mg content of needles at the 0% Mg level was significantly lower than at the 30% level, and in the second growth period a decline was clear at both deficiency levels. Swelling of phloem cells was observed in samples taken after 4 weeks' exposure, and the frequency of swollen phloem cells increased towards autumn and through the second growth period. At the end of the first growing period a decrease in the number of thylakoids per granum and an increase in the number of plastoglobuli in chloroplasts of mesophyll cells were detected at both deficiency levels. During the second growing period the tips of needles from the previous year in the 0% Mg level group became brown, and these needles were shed in autumn from some of the seedlings. The chloroplasts in these needles were rounded and the thylakoids were abnormally organized. Structural symptoms caused by Mg deficiency were observable before visual changes and before a clear decrease in Mg content had occurred, thus showing the value of structural observations in early diagnosis of this stress.

Development of corrosion flaws for the production of realistic test specimens

2020 ◽  
Vol 64 (1) ◽  
pp. 23-28
Author(s):  
J. Hodač ◽  
Z. Fulín ◽  
P. Mareš ◽  
J. Veselá ◽  
O. Chocholatý
Keyword(s):  
Power Plants ◽  
Galvanic Corrosion ◽  
Water Solution ◽  
Erosive Wear ◽  
Corrosion Damage ◽  
Water Mist ◽  
Carbon Steels ◽  
Bending Stress ◽  
Solution Flow ◽  
Mechanical Bending

AbstractTo produce realistic test specimens with realistic flaws, it is necessary to develop appropriate procedure for corrosion flaw production. Tested specimens are made from steels commonly used in power plants, such as carbon steels, stainless steels and their dissimilar weldments. In this study, corrosion damage from NaCl water solution and NaCl water mist are compared. Specimens were tested with and without mechanical bending stress. The corrosion processes produced plane, pitting and galvanic corrosion. On dissimilar weldments galvanic corrosion was observed and resulted to the deepest corrosion damage. Deepest corrosion flaws were formed on welded samples. The corrosion rate was also affected by the solution flow in a contact with the specimens, which results in a corrosion-erosive wear. Produced flaws are suitable as natural crack initiators or as realistic corrosion flaws in test specimens.

Silvicultural characteristics of a Scots pine stand on drift sands

1992 ◽  
Vol 57 ◽  
Author(s):  
D. Maddelein ◽  
N. Lust
Keyword(s):  
Scots Pine ◽  
Mixed Forest ◽  
Rotation Period ◽  
Average Height ◽  
Indigenous Species ◽  
Pedunculate Oak ◽  
Black Cherry ◽  
Humus Layer ◽  
Pine Seedlings ◽  
Pine Regeneration

The  study of a seventy years old stand of Scots pine on drift sands proves that  Scots pine growth on these sites was and is still relatively good: average  diameter 27.6 cm, average height 19.4 m, standing volume 213 m3 and an annual increment  of 4.9 m3.ha-1.yr-1. All Scots pines  belong to the upper storey. Yet considerable differences in crown development  and vitality are observed. The current growth rate and the spontaneous  settlement of pine seedlings under canopy show the ideal conditions for the  creation of a high forest with reserves. Anyway a rotation period of more  than 70 years is recommendable.     On several places a consolidated regeneration of Scots pine seedlings under  canopy occur. Groups with a stem number of 700 to 3,500 seedlings per are, ranging  in age from 3 to 11 years and in height from 10 to 170 cm, are present. This  Scots pine regeneration has developed in a normal mor humus layer and in a  dense Deschampsia mat.      Broadleaved regeneration is not so abundant, and consists for 75 % of black  cherry. Absence of seed trees, browsing damage and the exclusive character of  black cherry are the limiting factors for the installation and survival of  valuable indigenous species, such as pedunculate oak.     Provided that black cherry is removed and that the regeneration is  protected against wild damage, it is possible to create a mixed forest  dominated by Scots pine but with a considerable admixture of indigenous  broadleaved trees. However, if black cherry will not be sufficiently  controlled, it can be expected that in a first phase black cherry will  dominate the understorey, that it will prevent the regeneration of all other  species and that, very soon, it will form an almost single-species dominated  stage in forest succession.

scholarly journals Effect of Prunus serotina Ehrh. Volatile Compounds on Germination and Seedling Growth of Pinus sylvestris L.

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 846
Author(s):  
Aleksandra Halarewicz ◽  
Antoni Szumny ◽  
Paulina Bączek
Keyword(s):  
Pinus Sylvestris ◽  
Volatile Compounds ◽  
Scots Pine ◽  
Prunus Serotina ◽  
Gas Chromatography Mass Spectrometry ◽  
Volatile Fraction ◽  
Black Cherry ◽  
Allelopathic Potential ◽  
Pine Seedlings ◽  
Phytotoxic Effect

In temperate European forests invaded by Prunus serotina Ehrh. (black cherry), a reduction in the spontaneous regeneration capacity of Pinus sylvestris L. (Scots pine) is observed. It could be caused by various factors, including allelopathic properties of this invasive plant. In this study the phytotoxic effect of P. serotina volatile compounds on P. sylvestris and the seasonal variation in this effect were assessed. Simple assays showed that volatiles emitted from P. serotina leaves significantly inhibited root growth of P. sylvestris seedlings. Their negative effect on stem growth was much weaker. The strongest phytotoxic effect on Scots pine seedlings was caused by the volatiles emitted from the youngest black cherry leaves. In fresh foliage of P. serotina, nineteen volatile organic compounds were identified by gas chromatography–mass spectrometry (GC–MS). The dominant compound was benzaldehyde. On the basis of tests of linalool alone, it was found that this monoterpene present in the volatile fraction has a strong allelopathic potential and inhibits germination, root elongation and shoot elongation of pine seedlings. The results of our research suggest that volatile compounds from P. serotina leaves could limited survival of P. sylvestris individuals in the seedling phase.

scholarly journals Interacting effects of insect and ungulate herbivory on Scots pine growth

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Michelle Nordkvist ◽  
Maartje J. Klapwijk ◽  
La rs Edenius ◽  
Christer Björkman
Keyword(s):  
Plant Growth ◽  
Scots Pine ◽  
Growth Response ◽  
Insect Herbivory ◽  
Additive Effects ◽  
Significant Interaction Effect ◽  
Ungulate Herbivory ◽  
Pine Trees ◽  
Multiple Species ◽  
Species Specific

AbstractMost plants are subjected to damage from multiple species of herbivores, and the combined impact on plant growth can be non-additive. Since plant response to herbivores tends to be species specific, and change with repeated damage, the outcome likely depend on the sequence and number of attacks. There is a high likelihood of non-additive effects on plant growth by damage from mammals and insects, as mammalian herbivory can alter insect herbivore damage levels, yet few studies have explored this. We report the growth response of young Scots pine trees to sequential mammal and insect herbivory, varying the sequence and number of damage events, using an ungulate-pine-sawfly system. Combined sawfly and ungulate herbivory had both additive and non-additive effects on pine growth—the growth response depended on the combination of ungulate browsing and sawfly defoliation (significant interaction effect). Repeated sawfly herbivory reduced growth (compared to single defoliation) on un-browsed trees. However, on browsed trees, depending on when sawfly defoliation was combined with browsing, trees exposed to repeated sawfly herbivory had both higher, lower and the same growth as trees exposed to a single defoliation event. We conclude that the sequence of attacks by multiple herbivores determine plant growth response.

The relationship between multiple leaders and mechanical and frost damage to the apical meristem of Scots pine seedlings

1990 ◽  
Vol 20 (3) ◽  
pp. 280-284 ◽  
Author(s):  
Jarmo K. Holopainen
Keyword(s):  
Scots Pine ◽  
Apical Meristem ◽  
Dry Weight ◽  
Frost Damage ◽  
Night Temperature ◽  
Shoot Dry Weight ◽  
Frost Injury ◽  
Pine Seedlings ◽  
Before And After ◽  
Multiple Leaders

The responses of young Scots pine seedlings to mechanical apical meristem damage before and after 4 nights exposure to minimum night temperatures of −2.2 and −6.7 °C in controlled environment growth chambers were compared with control seedlings that were subjected or not to apical meristem damage and exposed to a minimum night temperature of 12 °C. The feeding damage caused by Lygus bugs was simulated by piercing the apical meristem of young pine seedlings with a hypodermic syringe needle and injecting a small drop of distilled water into the wound. At −6.7 °C increased numbers of dead seedlings were found. The proportion of seedlings with multiple leaders greatly increased after piercing, and about half of the seedlings subjected to the apical meristem damage had multiple leaders. The proportion of seedlings with multiple leaders and the number of leader shoots per seedling did not differ among seedlings subjected to apical meristem damage before or after the frost exposure. Short and twisted primary needles occurred in the basal parts of the new shoots in the seedlings with multiple leaders. Seedlings with necrotic needles were most often found after exposure to the night temperature of −6.7 °C. Shoot dry weight and length were significantly lower in seedlings subjected to apical meristem damage after frost exposure than in seedlings subjected to apical meristem damage before frost exposure or to no frost exposure. The results suggest that an increased reduction in growth is to be expected if Lygus bug attacks occur on pine seedlings that already suffer from frost injury.

scholarly journals A Comparative Study of the Pathogenicity of Fusarium circinatum and other Fusarium Species in Polish Provenances of P. sylvestris L.

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 560 ◽  
Author(s):  
Kateryna Davydenko ◽  
Justyna Nowakowska ◽  
Tomasz Kaluski ◽  
Magdalena Gawlak ◽  
Katarzyna Sadowska ◽  
...  
Keyword(s):  
Scots Pine ◽  
Fungal Pathogen ◽  
Fusarium Species ◽  
Pitch Canker ◽  
Fusarium Circinatum ◽  
Northern Spain ◽  
Fusarium Spp ◽  
Pine Seedlings ◽  
Unintentional Introduction ◽  
Different Levels

The fungal pathogen Fusarium circinatum is the causal agent of Pine Pitch Canker (PPC), a disease which seriously affects different species of pine in forests and nurseries worldwide. In Europe, the fungus affects pines in northern Spain and Portugal, and it has also been detected in France and Italy. Here, we report the findings of the first trial investigating the susceptibility of Polish provenances of Scots pine, Pinus sylvestris L., to infection by F. circinatum. In a greenhouse experiment, 16 Polish provenances of Scots pine were artificially inoculated with F. circinatum and with six other Fusarium species known to infect pine seedlings in nurseries. All pines proved highly susceptible to PPC and displayed different levels of susceptibility to the other Fusarium spp. tested. The findings obtained indicate the potentially strong threat of establishment of an invasive pathogen such as F. circinatum following unintentional introduction into Poland.

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