Transport, Distribution and Consumption of Pine and Spruce 14C-Assimilates in Northern Phytocenoses under Different Illumination and Nitrogen Nutrition
Journal Title: Lesnoy Zhurnal (Russian Forestry Journal) - Year 2020, Vol 18, Issue 4
Abstract
A rational system of cuttings, mineral nutrition of plants, and preservation of softwood undergrowth during felling is one of the ways to increase the productivity of boreal forests. The physiological methods of research used in forestry and, first of all, the study of donoracceptor interactions, allow obtaining the necessary information on the efficiency level of forestry measures in the stands of pine and spruce undergrowth quickly enough (within 1–2 years) without waiting for the final result in the form of an increment in shoots. The dynam ics of accumulation, transportation and distribution of 14C in organs and tissues of a tree under the influence of selective cuttings and a nitrogen dose has been studied in spruce and pine undergrowth in stands of different species composition and age. The study objects have been: blueberry spruce and birch forests of the forest site types with varying intensity of cutting; lichen pine forests formed from pine undergrowth preserved during the cutting. It were found that, in the summer period under the canopy of spruce and birch forests, the illumination does not exceed 8–10 % of the open area and does not correspond to the biological norm for spruce. The lack of solar radiation and soil nitrogen in the undergrowth of these tree species leads to a decrease in the intensity of photosynthesis and the violation of donoracceptor bonds, delays evacuation of assimilates from a leaf and their transportation to the active zones, suppresses the growth activity and the associated with it “demand” for macronutrients sent to the leaves declines the vitality of plants. The efficiency of the root system deteriorates, the formation of a new assimilation apparatus is delayed, and the growth processes of vegetative organs are violated due to the lack production of assimilates and the disruption of their distribution system. Nitrogen introduced into the stands and selective cuttings in pine and spruce undergrowth activate the synthetic and absorption activity of the root system, improve the functioning of the assimilation apparatus, strengthen the donoracceptor interactions between the aboveground and underground organs of a tree, significantly accelerate the outflow of photosynthetic products from a leaf, and positively influence on the growth processes. It has been found that, according to the level of activity of the donor-acceptor system for the pine and spruce undergrowth, it is possible within 1–2 years to set up a system of felling and a dose of nitrogen introduced into the forest stands that most closely meet the needs of these species.
Authors and Affiliations
V. N. Konovalov, L. V. Zarubina
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