Download The cyclic dynamics of northern trees photosynthesis capacity

The cyclic dynamics of northern trees photosynthetic capacity
P.A.Kashulin, N.V.Kalacheva, V.K. Zhirov
Polar-Alpine Botanical Garden-Institute, Apatity, Russia
The contemporary approaches to registration means of the local biological responses on global
biosphere changes simultaneously with possible cosmic fine effects on terrestrial biota life
suggest the wide use of remote-sensing and noninvasive, but sensitive methods. Such state-ofthe-art technique provides an investigator by current data with minimal disturbance of the living
objects.
Long-term monitoring for photosynthetic capacity of indicator flora species was carried out in
terms of noninvasive optical method which have been included chlorophyll fluorescence
measurements in situ emitted up the surface of native foliage. The pulse amplitude modulated
PAM-2100 portable chlorophyll fluorometer from Heinz Walz Effetrich (Germany) was used.
The parallel daily PAR, UV, temperature and humidity measurements for the plant vegetation
local points were carried out also. The ran current data were as follows: Fo and Fm – minimal
dark and maximal chlorophyll fluorescence, respectively; derivative parameter Fv/Fm which is a
measure of the maximal quantum yield of photosystem II and some other indices.
The midday and evening chlorophyll fluorescence measurements of Salix caprea L., Populus
tremula L., Betula pendula Roth, Lonicera edulis Turcz. Ex Freyn., Lonicera tatarica L.,
Syringa josikaea Jacq. fil arboreal deciduous plants were carried out daily, starting of June to
October/ Both 2014 yr and 2015 yr seasons are considered.
The photosynthesis capacities of the plants throughout whole vegetation season were compared
between different biological species and with UV, PAR, temperature. A number of cycles in Fo,
Fm and Fv/Fm seasonal dynamics were revealed in terms of spectral analysis for the rows
obtained. The most robust periods registered were as follows: circaseptan (about 7-day) and
circasemiceptan (about 3,5-day), the cycles about 14-day, a number of larger period cycles were
found also. The relation of the plant photosynthesis capacity with climatic, geophysical indices
and plausible cosmic provenance of the cycles found are discussed.