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

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.

2019 ◽  
Vol 40 (2) ◽  
pp. 198-214 ◽  
Author(s):  
Antti Tenkanen ◽  
Sarita Keski-Saari ◽  
Jarkko Salojärvi ◽  
Elina Oksanen ◽  
Markku Keinänen ◽  
...  

Abstract Due to its ubiquity across northern latitudes, silver birch (Betula pendula Roth) is an attractive model species for studying geographical trait variation and acclimation capacity. Six birch provenances from 60 to 67°N across Finland were grown in a common garden and studied for provenance and genotype variation. We looked for differences in height growth, photosynthetic gas exchange and chlorophyll content index (CCI) and compared the gas exchange of early and late leaves on short and long shoots, respectively. The provenances stratified into southern and northern groups. Northern provenances attained less height growth increment and had higher stomatal conductance (gs) and lower intrinsic water-use efficiency (WUE, Anet/gs) than southern provenances, whereas net photosynthesis (Anet) or CCI did not show clear grouping. Short shoot leaves had lower gs and higher WUE than long shoot leaves in all provenances, but there was no difference in Anet between shoot types. The separation of the provenances into two groups according to their physiological responses might reflect the evolutionary history of B. pendula. Latitudinal differences in gas exchange and water use traits can have plausible consequences for global carbon and water fluxes in a warming climate.


2005 ◽  
Vol 35 (3) ◽  
pp. 703-712 ◽  
Author(s):  
Elina Oksanen ◽  
Vera Freiwald ◽  
Nadezhda Prozherina ◽  
Matti Rousi

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.


2021 ◽  
Vol 22 (14) ◽  
pp. 7269
Author(s):  
Jean-Stéphane Venisse ◽  
Eele Õunapuu-Pikas ◽  
Maxime Dupont ◽  
Aurélie Gousset-Dupont ◽  
Mouadh Saadaoui ◽  
...  

Aquaporin water channels (AQPs) constitute a large family of transmembrane proteins present throughout all kingdoms of life. They play key roles in the flux of water and many solutes across the membranes. The AQP diversity, protein features, and biological functions of silver birch are still unknown. A genome analysis of Betula pendula identified 33 putative genes encoding full-length AQP sequences (BpeAQPs). They are grouped into five subfamilies, representing ten plasma membrane intrinsic proteins (PIPs), eight tonoplast intrinsic proteins (TIPs), eight NOD26-like intrinsic proteins (NIPs), four X intrinsic proteins (XIPs), and three small basic intrinsic proteins (SIPs). The BpeAQP gene structure is conserved within each subfamily, with exon numbers ranging from one to five. The predictions of the aromatic/arginine selectivity filter (ar/R), Froger’s positions, specificity-determining positions, and 2D and 3D biochemical properties indicate noticeable transport specificities to various non-aqueous substrates between members and/or subfamilies. Nevertheless, overall, the BpePIPs display mostly hydrophilic ar/R selective filter and lining-pore residues, whereas the BpeTIP, BpeNIP, BpeSIP, and BpeXIP subfamilies mostly contain hydrophobic permeation signatures. Transcriptional expression analyses indicate that 23 BpeAQP genes are transcribed, including five organ-related expressions. Surprisingly, no significant transcriptional expression is monitored in leaves in response to cold stress (6 °C), although interesting trends can be distinguished and will be discussed, notably in relation to the plasticity of this pioneer species, B. pendula. The current study presents the first detailed genome-wide analysis of the AQP gene family in a Betulaceae species, and our results lay a foundation for a better understanding of the specific functions of the BpeAQP genes in the responses of the silver birch trees to cold stress.


2021 ◽  
Vol 11 (6) ◽  
pp. 20-29
Author(s):  
Fetoon M ◽  
helaiwi Alk ◽  
Ismet Ara ◽  
Nadine Moubayed

Streptomyces are the most popular among the Actinomycetes groups and found in soils worldwide. They form an important part of the soil ecology within the Actinomycetales order. Streptomyces are diverse as secondary antibiotic metabolites such as Novobiocin, Amphotericin, Vancomycin, Neomycin, Gentamicin, Chloramphenicol, Tetracycline, Erythromycin and Nystatin. Thus, the current study was aimed to isolate, identify and assess the active antibiotic metabolites produced by different actinomyces sp. found in Saudi Arabian soils. Six samples were collected from desert soils of the Al Thumamah area and analyzed using GS-MS. Scanning Electron Microscopy was used to identify the bacterial strains along with their antibiotic metabolites effectiveness of secondary metabolites (antibiotics) against different Gram-positive (Bacillus subtilis, Staphylococcus aureus), negative pathogens (Pseudomonas aeruginosa, Escherichia coli, Salmonella suis, and Shigella sonnei) as well as the fungal strain Candida albicans was investigated. Thirty active bacterial (F1-30) strains were isolated from the soil samples and the strains F3, F7, F22, F30 have white, gray, pink, yellow and red colours respectively. Only ten strains (F13, F14, F15, F16, FI7, F18, F19, F20, F21, and F22) were found to have antimicrobial activity against at least one pathogen. The optimum growth environment was pH 4-10, temperature (300C), and NaCl (7% w/v) concentration. According to our findings, the extreme desert environment of Al Thumamah from Saudi Arabia is rich in its actinobacterial population with diverse colouring groups and various physiological and biochemical properties. This shows it’s capability of generating secondary metabolite elements that could inhibit pathogenic microorganisms.


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 ◽  
...  

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.


1993 ◽  
Vol 23 (12) ◽  
pp. 2459-2466 ◽  
Author(s):  
George J. Harper ◽  
Edith L. Camm

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.


1984 ◽  
Vol 14 (1) ◽  
pp. 77-84 ◽  
Author(s):  
R. O. Teskey ◽  
C. C. Grier ◽  
T. M. Hinckley

Seasonal changes in water relations and net photosynthesis were measured over a year in current and 1-year-old foliage of Abiesamabilis (Dougl.) Forbes, a subalpine conifer. Responses were compared with maximum rates achieved in older foliage. Current-year foliage developed slowly during the growing season. Although growth began on 22 June, highest rates of stomatal conductance and net photosynthesis did not occur until September and October. One-year-old foliage had the highest rates of net photosynthesis (12.9 mg CO2•dm−2•h−1) and stomatal conductance (3.1 mm•s−1) during the summer. Net photosynthesis decreased with needle age, but foliage as old as 7 years had rates of net photosynthesis as high as 5.0 mg CO2•dm−2•h−1. There was no evidence of photosynthetic adjustment to seasonal change in temperature. The optimum temperature for photosynthesis remained at 15 ± 1.5 °C throughout the year. No water stress was observed during the summer. Xylem water potential never decreased below −1.65 MPa and was always well above the turgor loss point. The lack of any apparent water stress, combined with photosynthetic characteristics, indicated that summer was the most important season for carbon gain. These results also suggested that a strategy for competitive success by Abiesamabilis in this cold, stressful environment is minimum dependence on the carbon gain of any individual age-class of foliage. Instead trees rely on the combined photosynthetic capacity of many years of foliage.


2011 ◽  
Vol 122 (3) ◽  
pp. 225-233 ◽  
Author(s):  
T.C. Zheng ◽  
X.K. Zhang ◽  
G.H. Yin ◽  
L.N. Wang ◽  
Y.L. Han ◽  
...  

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