Current issue: 58(5)
Silva Fennica vol. 8 no. 2 | 1974
Category : Article
After 64 days of aseptic culture, germlings of Pinus Syvestris L. were cut at the middle of the hypocotyl and above the root. The upper and lower halves of the hypocotyls were transferred onto agar medium RM-196 of Linsmaier & Skoog (1964) including 2 mg/l IAA and 0.1, 1 or 10 mg/l kinetin, one or both halves being put in each vial. Callus growth and root formation was observed after 55 days.
The lower ends of basally cut seedlings generally formed callus tissue and 20% of them also formed roots from this callus. No roots and less callus growth were observed in the lower hypocotyle halves excised at both ends. In the latter hypocotyles callus growth was promoted by the presence in the same vial of a basally excised germling, including cotyledons and plumule. Increasing amounts of kinetin slightly enhanced callus formation of basally excised germlings but seemed to inhibit callus growth in hypocotyls excised at both ends and placed alone on the growth medium. The total amount of callus was greatest in hypocotyls which included intact cotyledons and plumule.
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Luukkanen,
E-mail:
ol@mm.unknown
The paper describes a preliminary attempt to assess the long-term effect of urea application on the quantity of nitrogen available for plants in forest soil. The soil samples required for the study were collected from an experimental area which had been set up for investigations into both the single and joint effect on tree growth of two levels of each of urea and phosphorus application. The stand was a mixed forest of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) on Myrtillus type site with an average volume of 217.5 m3/ha.
According to the results, the nitrogen available for plants of the humus layer was significantly higher in fertilized than in unfertilized plots as late as four years after application. In terms of absolute values, the quantities were extremely small, only 3–4% of the amounts applied. In comparison with these results it was interesting to notice that urea application seemed to increase the C/N ratio.
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Westman,
E-mail:
cw@mm.unknown
The effect of spacing on the first-year yield and height increment of Alnus incana (L.) Moench, Populus tremula L. x Populus tremuloides Michx. (Populus x wettsteinii), Salix ’Aquatica Gigantea’, and Salix phylicifolia L. was studied at the Arctic Circle Agricultural Experimental Station in Northern Finland. S. ’Aquatica Gigantea’ gave yields which were twice as high as those of the other species in the study. The highest yields were of the order of 60 tons per hectare (fresh yield including foliage). The annual height growth in S. ’Aquatica Gigantea’ was about 100 cm, in the others about 30–50 cm. S. ’Aquatica Gigantea’ had a maximal height growth when the distance between the seedlings was 25 cm.
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Pohjonen,
E-mail:
vp@mm.unknown
In this study a formula has been developed to describe the influence of the change of cost level on such a mechanization prognosis, where is assumed that wages and machine costs bear compound interest. In the study there are some numerical examples.
In the formula p1 = annual per cent increase of wages, p3 = annual per cent increase of machine costs, p2 = sudden and incident per cent increase of machine costs, and tv = delay in the profitability of mechanization.
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Harstela,
E-mail:
ph@mm.unknown
In this paper the use of butt and top diameters of pulpwood bolts for volume determination is analysed. The study is based on the taper data of Scots pine (Pinus sylvestris L.) stems. According to the results, the use of the mean of butt and top diameters in the volume determination under Finnish condition causes a positive error in small stems. If the stems are so big that the butt portions of the stems can be used as saw logs, the remaining top bolts, used as pulpwood, are estimated to be smaller than they are in reality. Accordingly, there is a negative error.
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Kärkkäinen,
E-mail:
mk@mm.unknown
