Determination of growth and maintenance coefficients by calorespirometry

2004 ◽  
Vol 31 (9) ◽  
pp. 929 ◽  
Author(s):  
Sannali Matheson ◽  
Derek J. Ellingson ◽  
V. Wallace McCarlie ◽  
Bruce N. Smith ◽  
Richard S. Criddle ◽  
...  
Keyword(s):  
Growth Rates ◽  
Leaf Age ◽  
Leaf Tissue ◽  
Heat Rate ◽  
Regulation Of Respiration ◽  
Convolvulus Arvensis ◽  
Verbascum Thapsus ◽  
Mature Leaves ◽  
Substrate Variation ◽  
Maintenance Coefficients

This study describes a calorespirometric method for determining the coefficients of the correlation of specific respiration and growth rates. To validate the calorespirometric method, coefficients obtained from calorespirometric data are compared with coefficients obtained from mass and elongation growth rates measured at three temperatures on oat (Avena sativa L.) shoots. Calorespirometric measurements were also made on leaf tissue of varying age from Verbascum thapsus L., Convolvulus arvensis L., and Helianthus tuberosus Nutt. Measurements on A. sativa, C. arvensis and H. tuberosus at several temperatures show maintenance coefficients generally increase with temperature, but, in disagreement with accepted theory, growth coefficients for C. arvensis and A. sativa vary with temperature. A comparison of rates expressed as intensive and extensive quantities showed that the decline in specific respiration and growth rates with age is caused by dilution-by-growth, not down-regulation of respiration rate by reduced demand. The ratio of heat rate to CO2 rate increases with leaf age, and, for fully mature leaves, exceeds the maximum possible value for carbohydrates. This shows that the catabolic substrate may vary with leaf age in immature leaves and cannot be assumed to consist only of carbohydrates in mature leaves. Dilution-by-growth, substrate variation, and inseparability of the variables in the growth-maintenance model all complicate physiological interpretation of the slope and intercept of plots of specific respiration rates v. specific growth rates.

Temporal and spatial distribution of BN28 during low temperature acclimation of Brassica napus cv. Cascade seedlings

1997 ◽  
Vol 75 (1) ◽  
pp. 28-35
Author(s):  
Mitchel D. de Beus ◽  
Anne M. Johnson-Flanagan ◽  
Joseph G. Boothe
Keyword(s):  
Brassica Napus ◽  
Low Temperature ◽  
Leaf Age ◽  
Temporal Distribution ◽  
Leaf Tissue ◽  
Temperature Acclimation ◽  
Ground Tissue ◽  
Temporal And Spatial Distribution ◽  
Apical Meristems ◽  
Mature Leaves

The objective of this study was to determine the spatial and temporal distribution of the peptide BN28 in Brassica napus cv. Cascade seedlings during low temperature acclimation. Immunoblots revealed that BN28 was present in leaves and shoot apical meristems of plants grown under low temperature but was absent from older tissues in the stem. Immunocytochemistry was used to determine the distribution throughout leaf and apical meristem tissues. BN28 was found throughout the apical meristems, was localized in the ground tissue and epidermis of young leaves, and was restricted to the ground tissue and guard cells in mature leaves. Differences in total accumulation were also noted, with the youngest leaves having the highest accumulation of BN28 and the quantity decreasing with leaf age. Despite these differences, plant developmental stage did not affect the accumulation of BN28 in individual leaves. Post-transcriptional controls are expected to regulate accumulation of the protein, as bn28 mRNA accumulates during acclimation in both young and mature leaves. Immunolocalization studies of BN28 in acclimated leaf tissue confirmed that BN28 is cytoplasmically localized and has no apparent weak association with organelles or other cellular membrane systems. Key words: acclimation, Brassica, development, immunocytochemistry, low temperature, protein synthesis.

Effect of Moisture Stress and Leaf Age on Bentazon Absorption in Common Cocklebur (Xanthium strumarium) and Velvetleaf (Abutilon theophrasti)

Weed Science ◽  
1995 ◽  
Vol 43 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Brian C. Levene ◽  
Micheal D. K. Owen
Keyword(s):  
Ammonium Nitrate ◽  
Plant Species ◽  
Leaf Age ◽  
Leaf Tissue ◽  
Moisture Stress ◽  
Abutilon Theophrasti ◽  
Xanthium Strumarium ◽  
Herbicide Application ◽  
Mature Leaves ◽  
Urea Ammonium Nitrate

More than 70% of all14C-bentazon absorption occurred within 4 h after herbicide application regardless of adjuvant Moisture stress reduced14C-bentazon absorption by common cocklebur and velvetleaf. Mature (second true leaf) and moisture-stressed leaves of velvetleaf had 50 and 17 μg cm−1more epicuticular wax (ECW) than did juvenile and unstressed leaves, respectively. Common cocklebur had less14C in the ECW and lower total14C in treated mature leaves compared to juvenile leaves. The use of 28% urea ammonium nitrate (UAN) or crop oil concentrate (COC) increased14C in ECW samples of both plant species, regardless of leaf age or moisture stress. More14C in the ECW did not always correlate with more14C in the leaf tissue. Adjuvants increased14C-bentazon absorption into leaves of plants that had been stressed.

scholarly journals The role of JrPPOs in the browning of walnut explants

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Shugang Zhao ◽  
Hongxia Wang ◽  
Kai Liu ◽  
Linqing Li ◽  
Jinbing Yang ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Production Efficiency ◽  
Phenolic Content ◽  
Leaf Tissue ◽  
Limiting Factor ◽  
Mature Leaves ◽  
Survival Percentage ◽  
Highly Active ◽  
Young Leaves

Abstract Background Tissue culture is an effective method for the rapid breeding of seedlings and improving production efficiency, but explant browning is a key limiting factor of walnut tissue culture. Specifically, the polymerization of PPO-derived quinones that cause explant browning of walnut is not well understood. This study investigated explants of ‘Zanmei’ walnut shoot apices cultured in agar (A) or vermiculite (V) media, and the survival percentage, changes in phenolic content, POD and PPO activity, and JrPPO expression in explants were studied to determine the role of PPO in the browning of walnut explants. Results The results showed that the V media greatly reduced the death rate of explants, and 89.9 and 38.7% of the explants cultured in V media and A media survived, respectively. Compared with that of explants at 0 h, the PPO of explants cultured in A was highly active throughout the culture, but activity in those cultured in V remained low. The phenolic level of explants cultured in A increased significantly at 72 h but subsequently declined, and the content in the explants cultured in V increased to a high level only at 144 h. The POD in explants cultured in V showed high activity that did not cause browning. Gene expression assays showed that the expression of JrPPO1 was downregulated in explants cultured in both A and V. However, the expression of JrPPO2 was upregulated in explants cultured in A throughout the culture and upregulated in V at 144 h. JrPPO expression analyses in different tissues showed that JrPPO1 was highly expressed in stems, young leaves, mature leaves, catkins, pistils, and hulls, and JrPPO2 was highly expressed in mature leaves and pistils. Moreover, browning assays showed that both explants in A and leaf tissue exhibited high JrPPO2 activity. Conclusion The rapid increase in phenolic content caused the browning and death of explants. V media delayed the rapid accumulation of phenolic compounds in walnut explants in the short term, which significantly decreased explants mortality. The results suggest that JrPPO2 plays a key role in the oxidation of phenols in explants after branch injury.

Selection for biomass production based on respiration parameters in eucalypts: effects of origin and growth climates on growth rates

1996 ◽  
Vol 26 (9) ◽  
pp. 1556-1568 ◽  
Author(s):  
Thimmappa S. Anekonda ◽  
Richard S. Criddle ◽  
Lee D. Hansen ◽  
Mike Bacca
Keyword(s):  
Temperature Dependence ◽  
Growth Rates ◽  
Heat Rate ◽  
Eucalyptus Species ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Metabolic Heat ◽  
Respiratory Parameters ◽  
Metabolic Heat Rate ◽  
Different Climates

Seventeen Eucalyptus species and 30 rapid-growing Eucalyptuscamaldulensis trees (referred to as plus trees), growing in a plantation were studied to examine relationships among measured plant growth and respiratory parameters, geographical origins, and growth climate. The respiratory parameters measured at two different temperatures by isothermal calorimetry were metabolic heat rate, rate of CO2 production, and the ratio of heat rate to CO2 rate. Metabolic heat rate was also measured as a continuous function of temperature by differential scanning calorimetry in the range of 10 to 40 °C. Tree growth was measured as rates of height and stem volume growth. The values of respiratory and growth variables of Eucalyptus species are significantly correlated with latitude and altitude of origin of their seed sources. The maximum metabolic heat rate, the temperature of the maximum heat rate, the temperature coefficients of metabolic rate, and the temperatures at which the slopes of Arrhenius plots change are all genetically determined parameters that vary both within and among species. Measurement of growth rate–respiration rate–temperature relationships guide understanding of why relative growth rates of Eucalyptus species and individual genotypes differ with climate, making it possible to identify genotypes best suited for rapid growth in different climates. The temperature dependence of respiration rates is an important factor determining relative growth rates of eucalypts in different climates. To achieve optimum biomass production the temperature dependence of individual plants must be matched to growth climate.

scholarly journals Meteorological conditions, ozone concentration and leaf age affect gas exchange in Psidium guajava ‛Palumaʼ

Hoehnea ◽  
2017 ◽  
Vol 44 (2) ◽  
pp. 236-245 ◽  
Author(s):  
Juliana Moreno Pina ◽  
Sérgio Tadeu Meirelles ◽  
Regina Maria de Moraes
Keyword(s):  
Gas Exchange ◽  
Ozone Concentration ◽  
Leaf Age ◽  
Psidium Guajava ◽  
Meteorological Conditions ◽  
Gas Exchanges ◽  
Mature Leaves ◽  
Young Leaves ◽  
Entire Experiment ◽  
The City

ABSTRACT This study aimed to investigate the importance of leaf age, meteorological conditions and ozone concentration (O3) on gas exchange of Psidium guajava ‛Paluma'. Saplings were grown and exposed in standard conditions in the city of São Paulo, in six periods of three months with weekly measurements in young and mature leaves. Gas exchanges were higher in young leaves for almost the entire experiment. Mature leaves showed greater reduction in gas exchange. The multivariate analysis of biotic and abiotic variables indicated that vapor pressure deficit (VPD), O3 concentration and radiation were the main variables associated with gas exchange decrease in young leaves. In mature leaves the influence of VPD is lower, but the temperature importance is higher. Moreover, the opposition between assimilation and O3 is more evident in mature leaves, indicating their greater sensitivity to O3.

scholarly journals Potential and restrictions of Poincianella pyramidalis (Tul.) L. P. Queiroz as native forage in the Brazilian semi-arid region

2019 ◽  
Vol 42 ◽  
pp. e47460
Author(s):  
Andrezza Araújo de França ◽  
Divan Soares da Silva ◽  
Josean Tavares Fechine ◽  
Francinilda Alves de Sousa ◽  
Alberício Pereira de Andrade ◽  
...  
Keyword(s):  
Leaf Age ◽  
Plant Defence ◽  
Leaf Tissue ◽  
Secondary Compounds ◽  
Mineral Matter ◽  
Endemic Plant ◽  
Leaf Maturity ◽  
13C Nuclear Magnetic Resonance

Poincianella pyramidalis (catingueira) is a endemic plant of the Caatinga, selected by animals grazing on native pasture. With the aim of evaluating characteristics indicative of its nutritional quality, 10 plants were selected and identified, sampled at five different ages, were used to determine dry matter (DM), crude protein (CP), neutral detergent fibre (NDF), mineral matter (MM), DM degradability (Deg DM), NDF degradability (Deg NDF) and in situ and in vitro leaf-tissue degradability. Phytochemical prospection was performed, and 1H and 13C nuclear magnetic resonance applied to detect the presence of secondary compounds. The data were submitted to analysis of variance and Tukey’s test at 5%, and correlation analysis was carried out on the variables for leaf maturity in days. The levels of CP, NDF and Deg NDF showed a negative correlation with the increases in leaf age. Leaf-tissue degradation was restricted due to a physical barrier developed in the leaf fragments, which can be attributed to plant defence mechanisms. The in situ degradability of the cell wall components decreased with the increase in leaf age. The high levels of tannins and lignin, and the strong presence of flavonoids, should be considered for their anti-nutritional and pharmacological potential.

Canopy position affects photosynthesis and anatomy in mature Eucalyptus trees in elevated CO2

2020 ◽  
Author(s):  
K Y Crous ◽  
C Campany ◽  
R Lopez ◽  
F J Cano ◽  
D S Ellsworth
Keyword(s):  
Elevated Co2 ◽  
Anatomical Variation ◽  
Leaf Age ◽  
Net Photosynthesis ◽  
Leaf Mass Per Area ◽  
Mesophyll Conductance ◽  
Mature Leaves ◽  
Canopy Position ◽  
Palisade Cells

Abstract Leaves are exposed to different light conditions according to their canopy position, resulting in structural and anatomical differences with consequences for carbon uptake. While these structure–function relationships have been thoroughly explored in dense forest canopies, such gradients may be diminished in open canopies, and they are often ignored in ecosystem models. We tested within-canopy differences in photosynthetic properties and structural traits in leaves in a mature Eucalyptus tereticornis canopy exposed to long-term elevated CO2 for up to three years. We explored these traits in relation to anatomical variation and diffusive processes for CO2 (i.e., stomatal conductance, gs and mesophyll conductance, gm) in both upper and lower portions of the canopy receiving ambient and elevated CO2. While shade resulted in 13% lower leaf mass per area ratio (MA) in lower versus upper canopy leaves, there was no relationship between leaf Nmass and canopy gap fraction. Both maximum carboxylation capacity (Vcmax) and maximum electron transport (Jmax) were ~ 18% lower in shaded leaves and were also reduced by ~ 22% with leaf aging. In mature leaves, we found no canopy differences for gm or gs, despite anatomical differences in MA, leaf thickness and mean mesophyll thickness between canopy positions. There was a positive relationship between net photosynthesis and gm or gs in mature leaves. Mesophyll conductance was negatively correlated with mean parenchyma length, suggesting that long palisade cells may contribute to a longer CO2 diffusional pathway and more resistance to CO2 transfer to chloroplasts. Few other relationships between gm and anatomical variables were found in mature leaves, which may be due to the open crown of Eucalyptus. Consideration of shade effects and leaf-age dependent responses to photosynthetic capacity and mesophyll conductance are critical to improve canopy photosynthesis models and will improve understanding of long-term responses to elevated CO2 in tree canopies.

scholarly journals Differential responses between mature and young leaves of sunflower plants to oxidative stress caused by water deficit

2010 ◽  
Vol 40 (6) ◽  
pp. 1290-1294 ◽  
Author(s):  
Inês Cechin ◽  
Natália Corniani ◽  
Terezinha de Fátima Fumis ◽  
Ana Catarina Cataneo
Keyword(s):  
Water Stress ◽  
Gas Exchange ◽  
Leaf Gas Exchange ◽  
Intercellular Co2 Concentration ◽  
Leaf Age ◽  
Co2 Concentration ◽  
Mature Leaves ◽  
Young Leaves ◽  
Mda Content ◽  
Gas Exchange Characteristics

The effects of water stress and rehydration on leaf gas exchange characteristics along with changes in lipid peroxidation and pirogalol peroxidase (PG-POD) were studied in mature and in young leaves of sunflower (Helianthus annuus L.), which were grown in a greenhouse. Water stress reduced photosynthesis (Pn), stomatal conductance (g s), and transpiration (E) in both young and mature leaves. However, the amplitude of the reduction was dependent on leaf age. The intercellular CO2 concentration (Ci) was increased in mature leaves but it was not altered in young leaves. Instantaneous water use efficiency (WUE) in mature stressed leaves was reduced when compared to control leaves while in young stressed leaves it was maintained to the same level as the control. After 24h of rehydration, most of the parameters related to gas exchange recovered to the same level as the unstressed plants except gs and E in mature leaves. Water stress did not activated PG-POD independently of leaf age. However, after rehydration the enzyme activity was increased in mature leaves and remained to the same as the control in young leaves. Malondialdehyde (MDA) content was increased by water stress in both mature and young leaves. The results suggest that young leaves are more susceptible to water stress in terms of gas exchange characteristics than mature leaves although both went through oxidative estresse.

scholarly journals Distribution of the endophytic fungi community in leaves of Bauhinia brevipes (Fabaceae)

2011 ◽  
Vol 25 (4) ◽  
pp. 815-821 ◽  
Author(s):  
Mariana Patrícia Amorim Hilarino ◽  
Fernando Augusto de Oliveira e Silveira ◽  
Yumi Oki ◽  
Leonardo Rodrigues ◽  
Jean Carlos Santos ◽  
...  
Keyword(s):  
Spatial Variation ◽  
Host Plant ◽  
Endophytic Fungi ◽  
Leaf Development ◽  
Morphological Traits ◽  
Significant Contribution ◽  
Leaf Age ◽  
Mature Leaves ◽  
Tropical Biodiversity ◽  
Bauhinia Brevipes

Endophytic fungi represent large, yet unexplored components of biodiversity. This work evaluated the richness and the distribution of endophytes in the leaves of Bauhinia brevipes (Fabaceae). A total of 1110 colonies were recovered from the samples and grouped by their morphological traits into 126 taxa. The total number of taxa according to leaf development was: 102 in mature leaves, 93 in recently expanded leaves and 79 for unfolded leaves. The major endophyte genera were Phomopsis, followed by Dothiorella, Pestalotiopsis and Acremonium. The richness and the isolate numbers of endophytes were not statistically affected by leaf region. However, some taxa were leaf-age specific; six were isolated only from unfolded leaves, nine from recently expanded leaves and 17 were exclusively found in mature leaves. The composition of endophytes varied with leaf region; the similarities (Jaccard's Index) among the leaf regions of different leaf ages ranged from 0.36 to 0.46, indicating a high spatial variation in the community of endophytic fungi inside the leaves. The high richness of endophytes in this host plant highlights a significant contribution of fungi to tropical biodiversity and the need for further research in this area.

Spectral reflectance characteristics of eucalypt foliage damaged by insects

2001 ◽  
Vol 49 (6) ◽  
pp. 687 ◽  
Author(s):  
C. Stone ◽  
L. Chisholm ◽  
N. Coops
Keyword(s):  
Spectral Reflectance ◽  
Near Infrared ◽  
Leaf Age ◽  
Electromagnetic Spectrum ◽  
Similar Response ◽  
Leaf Ontogeny ◽  
Maximum Slope ◽  
Mature Leaves ◽  
Eucalypt Species ◽  
Red Coloration

Variables related to foliar damage, leaf morphology, spectral reflectance, chlorophyll fluorescence and chlorophyll content were measured from leaves sampled from mature eucalypts exhibiting symptoms of crown dieback associated with bell miner colonisation located in Olney State Forest, near Wyong, New South Wales. Insect-damaged mature leaves and healthy young expanding leaves of some species exhibited a conspicuous red coloration caused by the presence of anthocyanin pigmentation. For the mature leaves, the level of red coloration was significantly correlated with insect herbivory and leaf necrosis. Significant correlations were also found between the level of red pigmentation and the following four spectral features: maximum reflectance at the green peak (550 nm); the wavelength position and maximum slope of the red edge (690–740 nm) and the maximum reflectance at 750 nm in the near-infrared portion of the electromagnetic spectrum. While it has been shown that anthocyanin pigments are synthesised in some eucalypt species in response to certain abiotic stresses causing photoinhibition and activation of photoprotective mechanisms, this work proposes that biotic agents such as leaf damaging insects and fungal pathogens may induce a similar response in eucalypt foliage resulting in increased levels of anthocyanins. The potential of anthocyanin levels to be related to leaf ontogeny for some eucalypt species was also illustrated in the reflectance spectra. Thus, it is essential that leaf age be considered. This work demonstrates that the identification of a number of key features of leaf spectra can provide a basis for the development of a robust forest health indicator that may be obtained from airborne or spaceborne hyperspectral sensors.

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