Photosynthesis In Pine Research Articles

Data-Driven Modeling of Stomatal, Mesophyll, and Biochemical Regulation of Scots Pine Photosynthesis

Distinguishing between components (stomatal conductivity, mesophyll conductivity, carbon dioxide fixation in chloroplasts, and respiration) of the complex biochemical mechanism of plant photosynthesis is a challenging problem. To solve it, we used both experimental data obtained in natural conditions (time series of recorded indicators) and a specially designed experiment: determination of carbon dioxide compensation points. A specialized processing method (balanced identification) and the corresponding information technology made it possible to consider a number of models, unbiasedly evaluate the significance of the hypotheses, and determine the errors of models describing the dataset. The evolutionary method of modifying models (from simple to complex, with modeling error as the selection criterion) made it possible to choose a model whose complexity corresponds to the used experimental data. The model thus constructed is applied to calculate the assimilation of CO2 by forest ecosystems and WUE (Water Use Efficiency).

Comparison of the Ecophysiological Parameters of Pine and Spruce in the Serebryanoborsky Experimental Forest District

Research conducted in Serebryanoborsky forestry Institute of Forestry RAS. To evaluate gas exchange, an original setup based on an infrared gas analyzer was used. The installation created at the Forestry Institute of the Russian Academy of Sciences made it possible to simultaneously, round-the-clock receive daily changes in the intensity of photosynthesis and respiration of adult trunks of pine and spruce trees. It was found that the respiration of pine and spruce trunks, calculated on the surface of trunks, does not differ significantly, while the intensity of photosynthesis of spruce (when calculated on the surface area of needles) is almost two times lower than that of pine. However, we believe that when calculating the area of growth, the differences will be insignificant, since the mass of spruce needles in the stand is much greater than the mass of pine needles per unit area of growth. It was found that the intensity of photosynthesis of spruce is more affected by moisture deficiency. So, during the day, with a PVPL equal to -0.8 MPa, on a cloudy day from 9 oclock it reduces the intensity of photosynthesis, whereas in pine only after 12 hours. On cloudy days, spruce with the same water supply practically does not decrease the intensity of photosynthesis during the whole day, and differences in the light curves of photosynthesis of pine and spruce are less significant. The calculation of pine and spruce trunk respiration per day depends on the arrival of solar radiation on cloudy days, the respiration rate is two times weaker than on low-cloud days. Thus, environmental and physiological indicators reflect the state of stands. The most informative indicator is the predawn water potential of the leaf (needles). This indicator characterizes the water availability of the tree, regardless of the reason for the decrease in water availability. The daily course of photosynthesis intensity and CO2 emission from the surface of the trunks are also informative indicators of the state of trees. However, when comparing different breeds by shade tolerance, it is better to use breathing from the surface of the trunks. Приведены результаты оценки влияния окружающей среды на эколого-физиологические показатели ели обыкновенной и сосны обыкновенной. Установлено, что дыхание стволов сосны и ели при расчете за сутки зависит от поступления солнечной радиации: в пасмурные дни интенсивность дыхания в 2 раза слабее, чем в малооблачные. При недостатке влаги интенсивность фотосинтеза ели снижается в большей степени, чем у сосны.

Физиологические исследования древесных растений

Приведены результаты изучения водного и светового режимов, а также углеродного баланса лесов в разных лесорастительных зонах, засухоустойчивости и теневыносливости разных пород деревьев. Построена математическая модель определения углеродного баланса разных пород в различных климатических условиях. Разработана методика оценки фотосинтетической продуктивности древостоев, основанная на зависимости КПД использования солнечной радиации на фотосинтез охвоенных или облиственных побегов и поглощения пологом древостоя солнечной радиации. The Laboratory of Plant Physiology was founded at the Forest Institute in 1944 under the supervision of a member of correspondent USSR Academy of Sciences L.A. Ivanova. During this time, the laboratory studied the water, light conditions and carbon balance of the forest in different forest zones. The dependence of the number and spectral composition of PARs under the forest canopy on the throughput of the canopy of the forest stand was investigated. The physiological mechanism of drought tolerance of trees in the steppe zone has been studied. It has been shown that there are various ways of adapting tree species to drought. The joint existence of species with different types of adaptation of trees to arid conditions (for example, oak, fluffy ash and small-leaved elm) reduces the life of plantings. Artificial shading studied the effect of light deficiency on growth, leaf anatomy and carbon metabolism in seedlings of different species and revealed a physiological mechanism shade tolerance. The intensity of the processes of carbon metabolism photosynthesis and respiration of various organs of trees (leaves, branches of different ages, trunk, growth and sucking roots) and their dependence on external conditions were studied. The carbon balance of individual leaves, branches, trees and stands was calculated under different weather conditions. The crown structure of several tree species was studied, the carbon balance of branches of different ages, and their lifespan. A mathematical model of the carbon balance of different species is constructed, and on this basis the possibility of the existence of a forest depending on the climate is calculated. Ecological and physiological studies were conducted (root respiration and photosynthesis of pine and birch). A methodology has been developed for assessing photosynthetic productivity based on the dependence of the efficiency of the use of absorbed solar radiation on the photosynthesis of covered or leafy shoots and the absorption of solar radiation by the canopy. It was found that forestry and photosynthetic productivity differ only slightly in these methods. It was found that the stands of pine and birch growing in optimal forest conditions have almost the same productivity. Estimates of the effect of moisture deficiency in seedlings of tree species under the canopy of wood stand.

Annual cycle of Scots pine photosynthesis

Abstract. Photosynthesis, i.e. the assimilation of atmospheric carbon to organic molecules with the help of solar energy, is a fundamental and well-understood process. Here, we connect theoretically the fundamental concepts affecting C3 photosynthesis with the main environmental drivers (ambient temperature and solar light intensity), using six axioms based on physiological and physical knowledge, and yield straightforward and simple mathematical equations. The light and carbon reactions in photosynthesis are based on the coherent operation of the photosynthetic machinery, which is formed of a complicated chain of enzymes, membrane pumps and pigments. A powerful biochemical regulation system has emerged through evolution to match photosynthesis with the annual cycle of solar light and temperature. The action of the biochemical regulation system generates the annual cycle of photosynthesis and emergent properties, the state of the photosynthetic machinery and the efficiency of photosynthesis. The state and the efficiency of the photosynthetic machinery is dynamically changing due to biosynthesis and decomposition of the molecules. The mathematical analysis of the system, defined by the very fundamental concepts and axioms, resulted in exact predictions of the behaviour of daily and annual patterns in photosynthesis. We tested the predictions with extensive field measurements of Scots pine (Pinus sylvestris L.) photosynthesis on a branch scale in northern Finland. Our theory gained strong support through rigorous testing.

Ectomycorrhizal fungi affect Scots pine photosynthesis through nitrogen and water economy, not only through increased carbon demand

Symbiotic ectomycorrhizal fungi have been shown to enhance host plant photosynthesis because the fungal symbiont are claimed to increase belowground carbon (C) demand. We aimed to study the effect of eight common symbiotic ectomycorrhizal (ECM) fungi on Scots pine photosynthesis and carbon (C) allocation because very few studies have investigated this phenomenon under controlled axenic conditions. The CO2 assimilation, stomatal conductance, chlorophyll fluorescence parameters, biomass allocation, moisture content, mycorrhization rate, nitrogen (N) uptake and N content of Scots pine seedlings, with or without symbiotic fungi, were measured after a four month growth period under axenic laboratory conditions. We hypothesized that ECM fungi are capable of increasing plant CO2 assimilation compared to non-mycorrhizal control fungi by increasing belowground C demand. This hypothesis was not supported since mycorrhizal and non-mycorrhizal plants did not differ significantly in any of the photosynthesis-related parameters. In addition, the common assumption that ECM fungi impose a C cost on the host plant was not supported by our study because mycorrhizal plants had the same or larger biomass compared to non-mycorrhizal plants. However, the mycorrhizal seedlings had a lower N percentage and allocated relatively more N to roots than shoots compared to control sterile seedlings, and the mycorrhizal seedlings had lower water content. In general, Needle N and water content correlated positively with CO2 assimilation. Based on our results, the N distribution within plant and plants water economy are the main effects of mycorrhizal symbiosis that affect plant C allocation and photosynthesis. These factors need to be considered when mycorrhizal effect on plant net primary production (NPP) also under natural conditions is estimated.

Low soil temperatures increase carbon reserves in Picea mariana and Pinus contorta

Soil temperature can limit tree growth and function, but it is often unaddressed in understanding the successional status of trees. We tested how soil temperature affected carbon allocation strategies of two dominant co-occurring boreal conifer species, Pinus contorta and Picea mariana. We measured nonstructural carbon (NSC) concentrations, biomass, and photosynthesis of dormant and actively growing 2-year-old seedlings in response to three soil temperatures (5, 10, and 20 °C) under a common ambient air temperature. For both species, variation in carbon reserves with soil temperature was more pronounced following seedling growth than during dormancy. For both species and all organ types (roots, needles, and stems), NSC concentrations were highest when seedlings were grown at 5 than 20 °C. Mass adjusted for NSC content was negatively correlated with NSC concentration for all organ types of both species. Soil temperature had a marginally significant effect on photosynthesis of pine; seedlings grown at 10 or 20 °C acquired more carbon than seedlings grown at 5 °C. Spruce seedlings photosynthesized more when grown at 20 °C than at 5 or 10 °C. Interspecific differences in allocation of carbon may underlie the responses of P. mariana and P. contorta to cold soils and consequently their successional status.

A Plant Notices Insect Egg Deposition and Changes Its Rate of Photosynthesis

Scots pine (Pinus sylvestris) is known to change its terpenoid metabolism in response to egg deposition by the sawfly Diprion pini (Hymenoptera, Diprionidae). Three days after egg deposition, parts of the pine twig adjacent to the egg-laden one are induced to emit volatiles, which attract egg parasitoids. In this study, we investigated whether egg deposition by this sawfly affects pine photosynthesis. Measurements of photosynthesis were taken from untreated control twigs and from pine twigs adjacent to egg-laden ones (i.e. systemically oviposition-induced twigs) for a period of 3 d starting after egg deposition. The net photosynthetic rate of oviposition-induced pine twigs was lower than that of untreated control twigs, whereas the respiration rate of pine twigs was not affected by egg deposition. CO2 response curves of oviposition-induced twigs tended to be lower than those of controls. The potential rate of electron transport (J(max)) and the maximum rate of Rubisco activity (V(cmax)) were calculated from the data of the CO2 response curves. J(max) of oviposition-induced twigs was significantly lower than that of controls at day 1 after egg deposition, while the difference diminished from day 2 to day 3. A similar pattern was observed for V(cmax). Light response curves of oviposition-induced twigs were significantly lower than those of untreated ones during 3 d of measurements. Stomatal conductance was slightly lowered by egg deposition. When considering photosynthetic activity as a physiological currency to measure costs of induction of plant defense, the effects of insect egg deposition on gas exchange of pine are discussed with respect to known effects of insect feeding on the photosynthesis activity of plants.

Effects of nitrogen on the growth of jack pine competing with Canada blue-joint grass and large-leaved aster

Biomass, leaf area, canopy photosynthesis, photosynthetic nitrogen-use efficiency (PNUE), nitrogen-partitioning ratio (NPR: ratio of nitrogen taken up by jack pine relative to two different competitor species), and nitrogen uptake (NU) of jack pine ( Pinus banksiana Lamb.) competing with large-leaved aster ( Aster macrophyllus L.) and Canada blue-joint grass ( Calamagrostis canadensis (Michx.) Beauv.) were examined at three nitrogen levels in a controlled-environment growth chamber. When grown with large-leaved aster, jack pine biomass, photosynthesis and PNUE ( p<0.001) increased as nitrogen level increased. Jack pine biomass, photosynthesis and NPR ( p<0.001) decreased as nitrogen level increased when grown with Canada blue-joint grass. At the lowest nitrogen supply level, jack pine photosynthesis decreased as competitor PNUE increased ( r 2=0.84, p<0.001). Jack pine photosynthesis decreased as NU of large-leaved aster (37.5 mg N l −1: r 2=0.75, p<0.001; 100 mg N l −1: r 2=0.86, p<0.001) and Canada blue-joint grass (37.5 mg N l −1: r 2=0.96, p<0.001; 100 mg N l −1: r 2=0.84, p<0.001) increased. NU and PNUE may play an important role in the outcome of interactions between jack pine seedlings and competing forest vegetation in newly planted stands.

Loblolly pine photosynthesis is enhanced by sublethal hexazinone concentrations

The effects of hexazinone on gas exchange and chlorophyll a fluorescence kinetics were investigated in container-grown loblolly pine (Pinus tueda L.) seedlings. Hexazinone at concentrations from 10m4 to lo-* M was applied as a soil drench. Photosynthesis in seedlings treated with hexazinone concentrations greater than 10m6 M was partially or completely inhibited throughout the 14-day study. Chlorophyll a fluorescence kinetics indicated that the inhibition was due to disruption of PSII electron transport. At hexazinone concentrations below 10m5 M, quantum yield and rates of photosynthesis and transpiration were increased on Day 1 and remained elevated through Day 7, whereas chlorophyll a fluorescence was unaffected. The results suggest that, in loblolly pine, hexazinone at sublethal concentrations may function in a manner similar to cytokinins.

Recovery of photosynthesis in winter‐stressed Scots pine

Abstract. . Winter‐induced inhibition of photosynthesis in Scots pine (Pinns sylvestris L.) is caused by the combined effects of light and freezing temperatures; light causes photoinhibition of photosystem II (Strand &amp; Oquist, 1985b, Physiologic Plantarum, 65, 117–123), whereas frost causes inhibition of enzymatic steps of photosynthesis (Strand &amp; Öquist, 1988, Plant, Cell &amp; Environment, 11, 231–238). To reveal limiting steps during recovery from winter stress, the potential of photosynthesis to recover and the actual recovery outdoors during spring, were studied in Scots pine. Studies of light dependent O2‐evolution under saturating CO2 and recordings of room temperature fluorescence induction kinetics were used. When branches of pine, in February and March, were brought into the laboratory and kept at 18°Cand 100μmol m−2 s−1, light saturated rates and apparent quantum yields of photo‐synthetic O2‐evolution recovered fully within approximately 48h. The photochemical efficiency of photosystem II, as measured by Fv/Fm ratios, recovered fully within 24h after an initial lag‐phase of 2‐3 h. Under natural winter conditions, the Fv/Fm ratio decreased more in exposed than in shaded pine, whereas the efficiency of photosynthesis was similarly inhibited in exposed and shadedpine. However, when recovery from winter stress occurred during spring, the Fv/Fm ratios of both shaded and exposed pine recovered well before photosynthesis. It is concluded that the light‐induced photoinhibition component of winter stress in photosynthesis of pine recovers well before the frost induced component(s) of winter stress. In this context, reversible photoinhibition of photosynthesis in evergreen conifers is considered as a dynamic down‐regulation of photosystem II to prevent more severe photodynamic damage of the thylakoid membrane when photosynthesis is inhibited by frost.

Recovery from winter depression of photosynthesis in pine and spruce

Recovery from winter depression of photosynthesis was studied in Pinus sylvestris, Pinus conforta and Picea abies by means of chlorophyll fluorescence and gas exchange measurements. During the winter 1986–1987 the fluorescence yield was low and no variable fluorescence was detectable before the end of March. In the field recovery of variable fluorescence/maximum fluorescence (Fv/Fm) during spring was slow for all three species studied. The temperature dependence of recovery was confirmed from measurements of the potential rate of recovery of Fv/Fm at different temperatures in the laboratory. At 20° C, Fv/Fm increased from 0.1 to 0.8 within 3 days. Recovery of Fv/Fm was paralleled by an increase in apparent photon yield. No significant differences could be demonstrated between the studied tree species in potential rate of recovery in the laboratory or in actual recovery in the field.

Photosynthesis and Growth Response of Red Spruce and Loblolly Pine to Soil-Applied Lead and Simulated Acid Rain

Abstract Soils from red spruce (Picea rubens Sarg.) and loblolly pine (Pinus taeda L.) stands were amended with either 0, 150, 300, 600 or 1200 mg/kg Pb as PbCl2. Six-month-old spruce and six-week-old pine seedlings were planted in their respective native soils and treated for 19 weeks with simulated rain of either pH 4.5 or 3.0. Rain was applied directly to the soil at a rate of 1.5 cm per week. Net photosynthesis, height, and needle, shoot, and root dry weights were measured at the completion of the experiment. In both soils, pH decreased and nitrate concentration increased with the application of a simulated rain solution of pH 3.0. Despite these changes in soil chemistry, simulated rain pH had no significant effect on the growth of either species. Red spruce photosynthesis was 35% higher; however, at a pH of 3.0. Loblolly pine photosynthesis was not affected by solution pH. Growth and photosynthesis of red spruce were inhibited even at the 150 mg/kg Pb level, with additional Pb resulting in increasing inhibition. Growth of loblolly pine seedlings was less sensitive to Pb, and decreased only at the higher concentrations. Loblolly pine photosynthesis exhibited no decline even at the highest Pb level. These results suggest that both red spruce and loblolly pine are more sensitive to soil Pb than to acid precipitation. In addition, loblolly pine appears to be more tolerant of Pb than red spruce, when both species are grown in their respective native soils. For. Sci. 33(3):668-675.

Effects of Ionizing Radiation on Rates of CO 2 Exchange of Pine Seedlings

Exposure to ionizing radiation is known to modify rates of metabolism of higher plants in various ways. Zill and Tolbert (1) showed that acute exposures to about 100 kR of y-radiation reduced rates of C02 fixation in wheat seedlings by 75 %. Field studies of CO2 exchange rates of Pinus rigida trees in the Brookhaven Irradiated Forest (2) showed reduction of rates of CO2 absorption under chronic irradiation at much lower total exposures than the acute exposures used by Zill and Tolbert. About 6000 R at 30 R/day reduced net photosynthesis to zero. The more detailed field studies of metabolic rates in this forest reported by Woodwell and Hadley (3) confirmed the depression of net photosynthesis by total exposures to 4000 to 7000 R at rates of less than 10 R/day and showed in addition that the patterns of C02 exchange of trees are modified by irradiation. The objective of the study reported here was to examine the effects of acute, rather than chronic, exposure to ionizing radiation on the pattern of CO2 exchange of pine seedlings under controlled conditions, to add to the previous field observations of chronically irradiated trees of Bourdeau and Woodwell (2) and Woodwell and Hadley (3). The experiments reported in this study show that acute exposures to as little as 1250 R depress rates of net photosynthesis of pine leaves without affecting rates of C02 evolution in the dark. Rates of C02 evolution by stems, however, were initially stimulated, but ultimately depressed by irradiation.

PHOTOSYNTHESIS AND ABSORPTION IN BLUE RADIATION

IN EARLIER work with white pine seedlings (Burns, 1937, 1938), a purely arbitrary value called the primary absorption spectrum was determined for each of the various types of plants. The primary absorption spectrum was the incident radiation minus the reflected, minus the amount transmitted by an acetone solution of the pigments at about the same concentration as in the plant. The spectra of the reflection, of the transmission, and of the sources were made with wide slits. Granted a constant quantum yield at the wave lengths involved and assuming that only radiation thus primarily absorbed was photosynthetically effective, the relative amounts of photosynthesis in the various portions of the spectrum were calculated and found to agree, within a few per cent, with the experimentally determined values at wave lengths greater than 5,000 A. To the extent of this rather surprising agreement, it was assumed that the primary absorption spectrum and the curve for photosynthesis at equal incident quanta intensity against wave lengtlh were the same within certain limits. However, between 4,000 A and 5,000 A, the amount of photosynthesis was found to be about onehalf of that indicated by the primary absorption spectrum. In contrast to this low photosynthesis in pine, Hoover (1937, fig. 1) found a maximum in wheat within this region. The results of other investigators vary and will not be included, since Gabrielsen (1940) has given a general review of this work. The main purpose of the experiments in this paper is to show that this difference in the behavior of pine and wheat in the blue region is due to differences in the two plants and not to errors or differences in the experimental methods. Since the same apparatus was also suitable for the partial investigation of several other problems, the results of these incomplete investigations, while not so conclusive, are also included. In the study of photosynthesis, curves giving the amounts of photosynthesis at equal incident quanta intensity against wave length are of value only in so far as they yield information on photosynthesis at equal absorbed quanta. The approximate agreement of the curves (fig. 1) for wheat and pine at wave lengths longer than 5,000 A, in spite of the obvious differences in color and absorption, shows that the corresponding curves on an absorbed quanta basis would differ. While accurate determinations of the fraction of incident radiation absorbed by a land plant under the conditions of these experiments is beyond our ability, such determinations as we have been able to make indicate that the amounts of photosynthesis in pine seedlings at 4,358 A, 5,461 A, and 5,780 A are less than would be called for by the absorbed quanta when compared to other wave lengths. The divergence is greatest at 4,358 A. In wheat this difference between the amount of photosynthesis and 'Received for publication November 26, 1941. Published with the consent of the Director of the Vermont Agricultural Experiment Station. absorption is not great enough to exceed the experimental errors of the determinations. It would appear that pine has more photosynthetically inactive absorption at these three wave lengths than wheat. The primary absorption spectra of various wheat plants were also determined, and the results indicate that, in this plant, there is no agreement between the primary absorption spectra and the amount of photosynthesis.