Influence of high-temperature convective flow on viability of Scots pine needles (Pinus sylvestris L.)

During a forest fire, plants are affected by high temperatures causing stress. At the time of burning, it is difficult to record temperature changes in tree crowns and the associated effects on photosynthesis. This paper presents the results of modelling a high-temperature effect simulating a convective flow from a ground fire. Evaluation of the response was carried out by the parameters of rapid fluorescence (Fv/Fm, ETR), the state of the pigment complex, and the relative water content in the needles. To characterize the degree of heat endurance and short-term effects concerning thermal damage, saplings of Scots pine (Pinus sylvestris L.) were used at different times during the growing season (June, July, August, September). Experimental heating at 55 C lasted for 5 and 10 min. There were different levels of heat resistance by the needles. Data in June show that heating of the saplings significantly suppressed photosynthesis. In July, August, and September, the photochemical quantum yield (Fv/Fm) was restored to 75% and 60% from the initial level after 5- and 10-min heating, respectively. The electron transport rate (ETR) for saplings in September was restored to their initial level within 3 days after a short heat exposure. Restoration of the photosynthetic activity in needles was observed after a 5-min impact, but by the end of the study period, restoration had not reached control values. A longer heating of 10 min resulted in an irreversible suppression of photosynthesis and destruction of the photosynthetic apparatus, as evidenced by the decrease in the number of photosynthetic pigments

How much carbon can the Siberian boreal taiga store: a case study of partitioning among the above-ground and soil pools

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.In the context of global carbon cycle management, accurate knowledge of carbon content in forests is a relevant issue in contemporary forest ecology. We measured the above-ground and soil carbon pools in the dark-coniferous boreal taiga. We compared measured carbon pools to those calculated from the forest inventory records containing volume stock and species composition data. The inventory data heavily underestimated the pools in the study area (Stolby State Nature Reserve, central Krasnoyarsk Territory, Russian Federation). The carbon pool estimated from the forest inventory data varied from 25 (t ha−1) (low-density stands) to 73 (t ha−1) (highly stocked stands). Our estimates ranged from 59 (t ha−1) (low-density stands) to 147 (t ha−1) (highly stocked stands). Our values included living trees, standing deadwood, living cover, brushwood and litter. We found that the proportion of biomass carbon (living trees): soil carbon varied from 99:1 to 8:2 for fully stocked and low-density forest stands, respectively. This contradicts the common understanding that the biomass in the boreal forests represents only 16–20 % of the total carbon pool, with the balance being the soil carbon pool. © 2015, Northeast Forestry University and Springer-Verlag Berlin Heidelberg

How much carbon can the Siberian boreal taiga store: a case study of partitioning among the above-ground and soil pools

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.In the context of global carbon cycle management, accurate knowledge of carbon content in forests is a relevant issue in contemporary forest ecology. We measured the above-ground and soil carbon pools in the dark-coniferous boreal taiga. We compared measured carbon pools to those calculated from the forest inventory records containing volume stock and species composition data. The inventory data heavily underestimated the pools in the study area (Stolby State Nature Reserve, central Krasnoyarsk Territory, Russian Federation). The carbon pool estimated from the forest inventory data varied from 25 (t ha−1) (low-density stands) to 73 (t ha−1) (highly stocked stands). Our estimates ranged from 59 (t ha−1) (low-density stands) to 147 (t ha−1) (highly stocked stands). Our values included living trees, standing deadwood, living cover, brushwood and litter. We found that the proportion of biomass carbon (living trees): soil carbon varied from 99:1 to 8:2 for fully stocked and low-density forest stands, respectively. This contradicts the common understanding that the biomass in the boreal forests represents only 16–20 % of the total carbon pool, with the balance being the soil carbon pool. © 2015, Northeast Forestry University and Springer-Verlag Berlin Heidelberg

Pathomorphological changes in the optic nerve in hypertencive disease

Гіпертонічна хвороба - це хронічне захворювання, клінічними ознаками якого є стійке підвищення артеріального тиску. Ускладнення якого призводять до часткової або повної втрати зору. Метою роботи було вивчення морфогенезу та гістотопографії патологічних змін зорового нерва у хворих на гіпертонічну хворобу. Досліджували матеріал гістологічних препаратів відділів зорового нерва здорових людей ( померлих в наслідок автотравми) та хворих на гіпертонічну хворобу ( померлих в наслідок ускладнень. Проведення морфологічних досліджень свідчить, що при гострому перебігу гіпертонічної хвороби спостерігаються зміни у вигляді мукоїдного, фібриноїдного набухання переважно в септальних артеріолах. При хронічному перебігу гіпертонічної хвороби поряд із мозаїчними деструктивними процесами в артеріях та артеріолах відбуваються компенсаторні процеси у вигляді міоеластозу, міогіпереластозу, що супроводжується збільшенням індексу Керногана; Гипертоническая болезнь - это хроническое заболевание, клиническими признаками которого являются стойкое повышение артериального давления, осложнения которого приводят к частичной или полной потере зрения. Целью работы было изучение морфогенеза и гистотопографии патологических изменений зрительного нерва у больных гипертонической болезнью. Исследовали материал гистологических препаратов отделов зрительного нерва здоровых людей (умерших вследствие автотравмы) и больных гипертонической болезнью (умерших вследствие осложнений). Проведенные морфологические исследования свидетельствует, что при остром течении гипертонической болезни наблюдаются изменения в виде мукоидного, фибриноидного набухания преимущественно в септальных артериолах. При хроническом течении гипертонической болезни наряду с мозаичными деструктивными процессами в артериях и артериолах происходят компенсаторные процессы в виде миоеластоза, миогипереластоза, что сопровождается увеличение индекса Керногана; Hypertensive disease is a chronic disease which clinical signs are sustained increase of blood pressure. The main pathogenetic mechanism of arterial hypertension is change in the relationship between the volume of circulating blood and general arterial resistance. Hypertensive disease clinically has benign and malignant course. . With benign hypertension there is a gradual development of episodes of short-term increase in blood pressure, then its steady increase, characterized by morphological changes in the vessels during the first and second stages of the disease. And in the third stage there are secondary changes in various organs in connection with the development in arterioles and arteries of sclerotic processes. It should be noted that during the benign course of hypertension in each of its stages there may be episodes of exacerbation with a sharp increase in blood pressure, which characterizes the malignant nature of the disease. The last are morphologically characterized by destructive lesions of arterioles in the form of plasmoragiosis and mucoid swelling of the vascular wall. Consequently, destructive changes in arterioles have a mosaic character. In this case, in some arteries simultaneously compensatory changes are determined, due to which the adaptation of vessels and surrounding tissues to the elevated blood pressure occurs. That is why the morphological changes of small arteries and arterioles with hypertension are manifested in two forms: hyalinism and hyperplastic arteriosclerosis. It should be noted that if morphological changes in the arterioles of the retina, as clinically and morphologically, are sufficiently described in the literature, then the morphological changes in the vessels accompanying the optic nerve are insufficiently described. The purpose of the work was to study morphogenesis and histopography of pathological changes in the optic nerve in patients with hypertension. The histological preparation material of the optic nerve was taking from healthy people (died as a result of autotrauma) and patients with hypertonic disease (died as a result of complications) was studied. Conclusions. The development of destructive processes in the optic nerve is associated with both plasmorrhagia and the gyalinosis of septal arterioles. At the same time, in these vessels, the formation of the wall or flat microtubes are noted. It is due to the presence of blood clots that develop ischemia in adjacent arterioles in the areas of the optic nerve. At the same time, on the transverse section of the optic nerve in areas of ischemic damage to the nerve fibers, granular cells are constantly found in the form of layers. The second pathogenetic factor of local circulatory disorders in the microcirculatory channel of the optic nerve is associated with increased vascular permeability, due to the presence of proteolytic enzymes in the cytoplasm of the endothelial cells. Precisely because of the presence of the latter increases the permeability of arterioles and capillaries. This is accompanied by diapedeous hemorrhages in the optic nerve tissue, which are caused by minor changes in the arterioles and capillaries