Reproductive Indicators of Nasczokin’s Lime (Tilia nasczokinii Stepanov)

Abstract

Tilia nasczokinii Stepanov (Naszokin’s lime) is endemic to the south of the Krasnoyarsk Territory and is of relict origin. Two of its populations grow in the vicinity of Krasnoyarsk on the left and right banks of the Yenisey River, being a part of pine forests and mixed pine-deciduous herb forests. The total number of the species is about 500 plant units, of which only 43 plants are currently bearing fruit. This research has determined the sizes and qualitative characteristics of T. nasczokinii fruits and seeds. The lime-capsules of T. nasczokinii, for 2 populations in general, have had the length of 5.7 ± 0.026 mm and the width of 5.0 ± ± 0.017 mm. The seeds have had the length of 3.6 ± 0.019 mm and the width of 2.9 ± 0.015 mm. It has been established that the lime-capsules in the left bank population are characterized by an elongated pear-shaped form, while in the right bank population the lime-capsules are spherical and slightly pointed at the top. In terms of the size of lime-capsules and seeds, T. nasczokinii did not differ statistically from the introduced T. cordata, which grows in the plantation under similar environmental conditions. In the left bank population, the masses of lime-capsules (18.3 g/1000 pcs.) and seeds (11.9–12.7 g/1000 pcs.) have turned out to be noticeably less than in the right bank population (lime-capsules – 24.8–29.9 g/1000 pcs., seeds – 16.1–18.0 g/1000 pcs.). In the left bank population, up to 60 % of the lime-capsules have been seedless and up to 43 % of the seeds have been empty. Seed viability has been equal to 17–32 %.In the right bank population, most of the lime-capsules have contained seeds (up to 91 %), and the proportion of empty lime-capsules has been small (up to 18 %). Seed viability has been equal to 66–83 %. Field germination of the seeds has been equal to 9.2 % (for some trees – up to 10.5 %) in the left bank population and 12.2 % (up to 21.1 %) in the right bank population. Despite the low field germination of the seeds in both populations, it is possible to obtain seed planting stock for creating artificial plantings of T. nasczokinii in order to preserve and restore the population of this rare relict species in the south of Central Siberia.