Photosynthesis of birch (Betula pendula) is sensitive to springtime frost and ozone

2005 ◽  
Vol 35 (3) ◽  
pp. 703-712 ◽  
Author(s):  
Elina Oksanen ◽  
Vera Freiwald ◽  
Nadezhda Prozherina ◽  
Matti Rousi
Keyword(s):  
Climate Change ◽  
Stomatal Conductance ◽  
Betula Pendula ◽  
High Capacity ◽  
Net Photosynthesis ◽  
Soluble Proteins ◽  
Nutrient Imbalance ◽  
Naturally Occurring ◽  
Negative Effect ◽  
Light Capture

Impacts of springtime frost and ozone enrichment, alone and in combination, on six birch (Betula pendula Roth) genotypes regenerated from a naturally occurring birch stand in southeastern Finland were studied. The seedlings were exposed to 65 ppb ozone (AOT40 (accumulated over a threshold of 40 ppb) exposure of 10.7 ppm·h) over 62 d in climate chambers, simulating spring conditions, and to –2 °C over two consecutive nights 33 d after the start of the experiment. The plants were measured for net photosynthesis, stomatal conductance, and concentrations of photosynthetic pigments, Rubisco, soluble proteins, carbohydrates, and macronutrients. Frost treatment caused a rapid 60%–77% decline in net photosynthesis and stomatal conductance rates. Recovery of net photosynthesis from frost was not complete during the subsequent 14 d, mainly because of impaired light capture through significant pigment loss and structural injuries. Concomitant ozone enrichment exacerbated the negative effect of frost on pigments and stomatal conductance. Both frost and ozone caused nutrient imbalance and increase in soluble proteins in leaves, whereas metabolism of carbohydrates was disturbed only when ozone was present. Responses to ozone and frost varied greatly among the genotypes, suggesting that there is a high capacity within the birch population to adapt to climate change through "preadapted" individuals.

Seasonal variation in physiological characteristics of two silver birch clones in the field

2003 ◽  
Vol 33 (11) ◽  
pp. 2164-2176 ◽  
Author(s):  
Johanna Riikonen ◽  
Elina Oksanen ◽  
Petri Peltonen ◽  
Toini Holopainen ◽  
Elina Vapaavuori
Keyword(s):  
Stomatal Conductance ◽  
Betula Pendula ◽  
Net Photosynthesis ◽  
Biochemical Properties ◽  
Rubisco Activity ◽  
Short Shoot ◽  
Growth Environment ◽  
Ozone Sensitivity ◽  
Spongy Layer ◽  
Leaf Ageing

Seasonal changes in growth, photosynthesis, and related biochemical properties and leaf structure were determined for two clones (4 and 80, 20 trees per clone) of 7-year-old Betula pendula Roth trees during the growing season of 1998. Differences between the two genotypes were determined to characterize the physiological traits that might affect growth and productivity and that might differ between the genotypes. Net photosynthesis of the short shoot leaves varied between 11 and 15 µmol·m–2·s–1 and decreased only slightly towards the end of the summer. However, our results showed more marked decreases in the amount of Rubisco (ribulose biphosphate carboxylase/oxygenase) and leaf N and increases in the total leaf, palisade and spongy layer thickness, chloroplast and starch grain size, and diameter of plastoglobuli in both clones in response to leaf ageing and changes in growth environment. Height and biomass were greater in clone 80 than in clone 4. This was related to slightly more efficient net photosynthesis and higher stomatal conductance and density as well as higher activity of Rubisco and content of foliar nutrients (other than N). We conclude that clone 80 is characterized by faster gas exchange, higher Rubisco activity, stomatal conductance, and density, and earlier leaf ageing, which may be related to the higher ozone sensitivity determined previously in pot experiments with younger saplings.

Buster Keaton’s Climate Change

2018 ◽  
Author(s):  
Jennifer Fay
Keyword(s):  
Climate Change ◽  
World War I ◽  
Storm Surges ◽  
Weather Conditions ◽  
Detailed Knowledge ◽  
World War ◽  
Precise Control ◽  
Naturally Occurring ◽  
Peter Sloterdijk ◽  
Slapstick Comedy

Much of Buster Keaton’s slapstick comedy revolves around his elaborate outdoor sets and the crafty weather design that destroys them. In contrast to D. W. Griffith, who insisted on filming in naturally occurring weather, and the Hollywood norm of fabricating weather in the controlled space of the studio, Keaton opted to simulate weather on location. His elaborately choreographed gags with their storm surges and collapsing buildings required precise control of manufactured rain and wind, along with detailed knowledge of the weather conditions and climatological norms on site. Steamboat Bill, Jr. (1928) is one of many examples of Keaton’s weather design in which characters find themselves victims of elements that are clearly produced by the off-screen director. Keaton’s weather design finds parallels in World War I strategies of creating microclimates of death (using poison gas) as theorized by Peter Sloterdijk.

scholarly journals Stomatal conductance limited the CO2 response of grassland in the last century

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Juan C. Baca Cabrera ◽  
Regina T. Hirl ◽  
Rudi Schäufele ◽  
Andy Macdonald ◽  
Hans Schnyder
Keyword(s):  
Climate Change ◽  
Stomatal Conductance ◽  
Nitrogen Nutrition ◽  
Physiological Control ◽  
Co2 Response ◽  
Nitrogen Acquisition ◽  
Wide Range ◽  
Park Grass Experiment ◽  
Conductance Changes ◽  
Canopy Stomatal Conductance

Abstract Background The anthropogenic increase of atmospheric CO2 concentration (ca) is impacting carbon (C), water, and nitrogen (N) cycles in grassland and other terrestrial biomes. Plant canopy stomatal conductance is a key player in these coupled cycles: it is a physiological control of vegetation water use efficiency (the ratio of C gain by photosynthesis to water loss by transpiration), and it responds to photosynthetic activity, which is influenced by vegetation N status. It is unknown if the ca-increase and climate change over the last century have already affected canopy stomatal conductance and its links with C and N processes in grassland. Results Here, we assessed two independent proxies of (growing season-integrating canopy-scale) stomatal conductance changes over the last century: trends of δ18O in cellulose (δ18Ocellulose) in archived herbage from a wide range of grassland communities on the Park Grass Experiment at Rothamsted (U.K.) and changes of the ratio of yields to the CO2 concentration gradient between the atmosphere and the leaf internal gas space (ca – ci). The two proxies correlated closely (R2 = 0.70), in agreement with the hypothesis. In addition, the sensitivity of δ18Ocellulose changes to estimated stomatal conductance changes agreed broadly with published sensitivities across a range of contemporary field and controlled environment studies, further supporting the utility of δ18Ocellulose changes for historical reconstruction of stomatal conductance changes at Park Grass. Trends of δ18Ocellulose differed strongly between plots and indicated much greater reductions of stomatal conductance in grass-rich than dicot-rich communities. Reductions of stomatal conductance were connected with reductions of yield trends, nitrogen acquisition, and nitrogen nutrition index. Although all plots were nitrogen-limited or phosphorus- and nitrogen-co-limited to different degrees, long-term reductions of stomatal conductance were largely independent of fertilizer regimes and soil pH, except for nitrogen fertilizer supply which promoted the abundance of grasses. Conclusions Our data indicate that some types of temperate grassland may have attained saturation of C sink activity more than one century ago. Increasing N fertilizer supply may not be an effective climate change mitigation strategy in many grasslands, as it promotes the expansion of grasses at the disadvantage of the more CO2 responsive forbs and N-fixing legumes.

scholarly journals Physiological responses of beet plants irrigated with saline water and silicon application

2020 ◽  
Vol 11 ◽  
pp. E3113
Author(s):  
José Sebastião de Melo Filho ◽  
Toshik Iarley da Silva ◽  
Anderson Carlos de Melo Gonçalves ◽  
Leonardo Vieira de Sousa ◽  
Mario Leno Martins Véras ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Carbon Concentration ◽  
Saline Water ◽  
Block Design ◽  
Essential Element ◽  
Net Photosynthesis ◽  
Crop Productivity ◽  
Experimental Unit ◽  
Randomized Block Design

Although not considered an essential element, silicon can be used to increase crop productivity, especially under stress conditions. In this sense, the objective was to evaluate the gas exchange of beet plants irrigated with saline water depending on the application of silicon. The experiment was conducted in a randomized block design, in a 5 x 5 factorial, referring to five levels of electrical conductivity of irrigation water (ECw): (0.5; 1.3; 3.25; 5.2 and 6.0 dS m-1) and five doses of silicon (0.00; 2.64; 9.08; 15.52 and 18.16 mL L-1), with six beet plants as an experimental unit. The effect of treatments on beet culture was evaluated at 30 and 60 days after irrigation with saline water from measurements of internal carbon concentration, stomatal conductance, net photosynthesis rate, instantaneous water use efficiency and instantaneous carboxylation efficiency using the LCpro+Sistem infrared gas analyzer (IRGA). Irrigation with saline water reduced the gas exchange of beet plants at 60 days after irrigation, but at 30 days after irrigation, the use of saline water increased stomatal conductance, transpiration rate and internal carbon concentration. The application of silicon decreased stomatal conductance, internal carbon concentration and efficiency in the use of water, but increased the rate of net photosynthesis, the rate of transpiration and instantaneous efficiency of carboxylation at 30 and 60 days after irrigation.

scholarly journals Queuine is a nutritional regulator of Entamoeba histolytica response to oxidative stress and a virulence attenuator

2020 ◽  
Author(s):  
Shruti Nagaraja ◽  
Maggi W. Cai ◽  
Jingjing Sun ◽  
Hugo Varet ◽  
Lotem Sarid ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Entamoeba Histolytica ◽  
Cysteine Proteases ◽  
Small Gtpases ◽  
Cytoskeletal Proteins ◽  
Transfer Rnas ◽  
Amebic Dysentery ◽  
Naturally Occurring ◽  
Expression Of Genes ◽  
Negative Effect

Queuosine is a naturally occurring modified ribonucleoside found in the first position of the anticodon of the transfer RNAs for Asp, Asn, His and Tyr. Eukaryotes lack pathways to synthesize queuine, the nucleobase precursor to queuosine, and must obtain it from diet or gut microbiota. Here we describe the effects of queuine on the physiology of the eukaryotic parasite, Entamoeba histolytica, the causative agent of amebic dysentery. Queuine is efficiently incorporated into E. histolytica tRNAs by a tRNA-guanine transglycosylase (EhTGT) and this incorporation stimulates the methylation of C38 in tRNAAspGUC. Queuine protects the parasite against oxidative stress (OS) and antagonizes the negative effect that oxidation has on translation by inducing the expression of genes involved in OS response, such as heat shock protein 70 (Hsp 70), antioxidant enzymes, and enzymes involved in DNA repair. On the other hand, queuine impairs E. histolytica virulence by downregulating the expression of genes previously associated with virulence, including cysteine proteases, cytoskeletal proteins, and small GTPases. Silencing of EhTGT prevents incorporation of queuine into tRNAs and strongly impairs methylation of C38 in tRNAAspGUC, parasite growth, resistance to OS, and cytopathic activity. Overall, our data reveal that queuine plays a dual role in promoting OS resistance and reducing parasite virulence.

Climate Change and Livestock Fertility

2022 ◽  
pp. 1256-1277
Author(s):  
Vishakha Shrimali ◽  
Nibedita Naha ◽  
Sukanta Mondal
Keyword(s):  
Climate Change ◽  
Heat Stress ◽  
Greenhouse Gases ◽  
Follicular Development ◽  
Mitigation Strategies ◽  
Adaptation To Climate Change ◽  
Oocyte Competence ◽  
Livestock Sector ◽  
Negative Effect ◽  
Global Threat

Climate change is a global threat to livestock sector to so many species and ecosystem in different parts of the world. Climate change, heat stress, and nutritional stress are the major intriguing factors responsible for reduced fertility in farm animals in tropical countries. Heat and nutritional stresses affect the reproductive performance by decreasing the expression of estrous behavior, altering ovarian follicular development and hormonal profiles, compromising oocyte competence, and inhibiting embryonic development in livestock. Climate is changed by greenhouse gases that released into atmosphere through man-made activities. Livestock contribute 18% of the production of greenhouse gases itself and causes climate change including heat stress, which has direct and indirect impact on fertility of the animals as well as reduce milk production. Adaptation to climate change and lowering its negative effect by alteration of animal micro-environment using different essential technologies are the main mitigation strategies to recover heat stress damage in this respect.

scholarly journals Xenon lamps used for fruit surface sterilization can increase the content of total flavonols in leaves of Lactuca sativa L. without any negative effect on net photosynthesis

PLoS ONE ◽  
2019 ◽  
Vol 14 (10) ◽  
pp. e0223787 ◽  
Author(s):  
Salah Fgaier ◽  
Mônica Maria de Almeida Lopes ◽  
Ebenézer de Oliveira Silva ◽  
Jawad Aarrouf ◽  
Laurent Urban
Keyword(s):  
Lactuca Sativa ◽  
Net Photosynthesis ◽  
Surface Sterilization ◽  
Lactuca Sativa L ◽  
Negative Effect ◽  
Xenon Lamps ◽  
Fruit Surface

scholarly journals Resilience to temperature and pH changes in a future climate change scenario in six strains of the polar diatom <i>Fragilariopsis cylindrus</i>

2015 ◽  
Vol 12 (14) ◽  
pp. 4235-4244 ◽  
Author(s):  
M. Pančić ◽  
P. J. Hansen ◽  
A. Tammilehto ◽  
N. Lundholm
Keyword(s):  
Climate Change ◽  
Growth Rates ◽  
Significant Interaction ◽  
Elevated Temperatures ◽  
Future Climate Change ◽  
Change Scenario ◽  
Ph Tolerance ◽  
Increased Temperature ◽  
Fragilariopsis Cylindrus ◽  
Negative Effect

Abstract. The effects of ocean acidification and increased temperature on physiology of six strains of the polar diatom Fragilariopsis cylindrus from Greenland were investigated. Experiments were performed under manipulated pH levels (8.0, 7.7, 7.4, and 7.1) and different temperatures (1, 5, and 8 °C) to simulate changes from present to plausible future levels. Each of the 12 scenarios was run for 7 days, and a significant interaction between temperature and pH on growth was detected. By combining increased temperature and acidification, the two factors counterbalanced each other, and therefore no effect on the growth rates was found. However, the growth rates increased with elevated temperatures by ~ 20–50 % depending on the strain. In addition, a general negative effect of increasing acidification on growth was observed. At pH 7.7 and 7.4, the growth response varied considerably among strains. However, a more uniform response was detected at pH 7.1 with most of the strains exhibiting reduced growth rates by 20–37 % compared to pH 8.0. It should be emphasized that a significant interaction between temperature and pH was found, meaning that the combination of the two parameters affected growth differently than when considering one at a time. Based on these results, we anticipate that the polar diatom F. cylindrus will be unaffected by changes in temperature and pH within the range expected by the end of the century. In each simulated scenario, the variation in growth rates among the strains was larger than the variation observed due to the whole range of changes in either pH or temperature. Climate change may therefore not affect the species as such, but may lead to changes in the population structure of the species, with the strains exhibiting high phenotypic plasticity, in terms of temperature and pH tolerance towards future conditions, dominating the population.

Effects of frozen storage duration and soil temperature on the stomatal conductance and net photosynthesis of Piceaglauca seedlings

1993 ◽  
Vol 23 (12) ◽  
pp. 2459-2466 ◽  
Author(s):  
George J. Harper ◽  
Edith L. Camm
Keyword(s):  
Stomatal Conductance ◽  
Soil Temperature ◽  
Carbon Fixation ◽  
Frozen Storage ◽  
Net Photosynthesis ◽  
Storage Duration ◽  
Growing Period ◽  
Soil Temperatures ◽  
Low Levels ◽  
And Storage

Nursery grown seedlings of Piceaglauca (Moench) Voss were stored frozen in the dark from approximately 10–31 weeks, thawed and grown for 28 days in a growth chamber at three soil temperatures (3, 7, and 11 °C). During the growing period gas exchange measurements were made every three days. Seedling net photosynthesis (pn) and stomatal conductance (gs) showed significant interactions between soil temperature and storage duration treatments. Soil temperature did not affect seedling gs or pn, though the degree and extent of storage duration effects were dependent on soil temperature. Recovery of gs occurred over a 4–7 day period from low levels after planting. Seedlings stored longer than 22 weeks showed lower rates of pn, than those stored for shorter durations. The lower pn in long-stored seedlings did not result from stomatal limitations to carbon fixation, as gs increased in seedlings stored >22 weeks.

Sign in / Sign up

Export Citation Format

Share Document