Germination studies on Scots pine (Pinus silvestris L.) seed of different provenances under alternating and constant temperatures
Kamra, Siri Krishan; Simak, Milan
In this investigation, he germination bel-iauiour of fresh Scots pine seed from ten autochthonous provenances lying between 47° and about 67° latitude was studied (cf: Table 1). The tests were carried out on Jacobsen apparatus at the constant temperatures of 20°C, 25°C, 30°C and 35°C and compared with those at the alternating temperature of 20-30°C (ISTA Rules, 1966), which was used as the standard. All germination values were calculated on the basis of the filled seeds only. It was found that: 1. The germination percentages at 20°C, 25°C and 20-30°C were the same for the northern provenances. Seed from the southern provenances germinated higher at 20°C and lower at 25°C than at 20-30°C (Figs. 1-11). The constant temperature of 20°C was found to be very suitable for the germination of Scots pine seed. 2. At 30°C and 35°C the germination values of the samples were lower than those at 20-30°C. 3. The origin of a seed sample seems to influence its germination percentage at a particular temperature. Thus the samples from the southern latitudes or the lower elevations were more sensitive to the temperatures used than those from the northern latitudes or the higher elevations. 4. The rate of germination at 20°C is in the first about seven days slower and later on equal or faster than that at 25°C, 30°C and 20-30°C. 5. The mould development on seed beds increased with increase in the temperature. 6. On the basis of the germination results reported in this paper, it is suggested that the constant temperature of 20°C is also included along with the alternating temperature of 20-30°C in the ISTA Rules for testing the germination of Scots pine seed.
germinations; Pinus sylvestris L.; seeds; temperature
Studia Forestalia Suecica
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