ტოგონიძე, ნატალია and ახალკაცი, მაია and Akhalkatsi, Maia (2010) ცის ექსპოზიციის გავლენა Primula-ს გვარის სახეობების ფენოლოგიურ რიტმზე. თბილისის ბოტანიკური ბაღის შრომები, 98 (1). pp. 55-71. ISSN 1512-1275
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Abstract
The effect of sky exposition on phenological rhythm in 6 species of genus Primula have been studied. P. woronowii is growing in shaded oak-hornbeam forests, P. macrocalyx occurs in Beech forest, P. amoena grows in two different habitats 1) subalpine Birch forest and 2) sub- and alpine meadows, two species (P. cordifoia, P. algida) occur only on alpine meadows and P. auriculata grows in wet meadows in subalpine zone. Sky exposition was used as general indicator of illumination character influencing the habitat microclimate. The fish-eye lens and computer program ”Gap Light Analyzer” were used to determine sky exposition cover percentage. The average value of sky exposition in studied sites (total 18 study sites) differed significantly. The differences were found in sky exposition average values in spring and late summer forests, which have been calculated for the same marked places in early spring, before leaves appeared on trees and in summer after they were covered with leaves. The sky exposition average value in summer forest was twice lower than in spring forest. Especially low sky exposition was determined in summer oak-hornbeam forest, where is growing P. woronowii. Very low sky exposition was shown in subalpine Birch forest in summer period. Alpine meadows have shown two times higher values of sky exposition than in spring forests and 6-8 times higher values than in summer forests. According to obtained results, alpine species start to flower after longer period of time after snow melting in the area than forest species. Moreover, early flowering species P. woronowii starts to flower almost parallel to snow melting period. Hence, the flower primordium is formed in autumn of the last year in all studied species, however, the development and growth of flowers in spring have different rhythmic. The elevation factor determines phenological phases in all species, however, the duration from snow melting to starting of flowering was very variable in studied species. We propose that early flowering in forest species, especially in more shaded forest species - P. woronowii, is determined by acceleration of phenological phases aiming completion of flowering and pollination period before leaves appear in forest and sky exposition and climatic conditions will be changed significantly. These processes might be explained as adaptation of forest Primula species to more shaded habitats than it is in alpine zone, where most species of this genus are growing. Adaptation to forest habitat, where the sky exposition is diminishing 4-5 times after trees are covered with leaves, means that the microclimatic conditions are changing in this area and the reproductive process should be influenced by lower temperature and solar radiation. This will cause changes in pollination and seed set. The obtained data confirm that reproductive effort of early flowering forest species of Primula shows close correlative relation to microclimatic conditions determined by sky exposition, such as temperature, moisture and solar radiation. It is expected that upcoming global climate change can cause shifts in "spring index" in forests and will change duration of phenological phases in shaded habitat of Primula. This will influence on reproductive success of the species and determine the chances of it's survival and propagation.
Item Type: | Article |
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Subjects: | Q Science > Ecology |
Depositing User: | Prof.Dr. Maia Akhalkatsi |
Date Deposited: | 07 Mar 2014 08:57 |
Last Modified: | 07 Mar 2014 08:57 |
URI: | http://eprints.iliauni.edu.ge/id/eprint/1326 |
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