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.

Trichome density and its protective potential against ultraviolet-B radiation damage during leaf development

1995 ◽  
Vol 73 (3) ◽  
pp. 376-383 ◽  
Author(s):  
George Karabourniotis ◽  
Dimitris Kotsabassidis ◽  
Yiannis Manetas
Keyword(s):  
Radiation Damage ◽  
Leaf Development ◽  
Leaf Age ◽  
Ultraviolet B ◽  
Eriobotrya Japonica ◽  
Trichome Density ◽  
Cydonia Oblonga ◽  
Leaf Hairs ◽  
Ultraviolet B Radiation ◽  
Mature Leaves

Trichome density and the capacity of leaf hairs to protect underlying tissues against ultraviolet-B radiation damage were assessed during leaf development in three tree species. In all cases, trichome density and the relative quantities of ultraviolet radiation absorbing phenolic constituents (expressed on a leaf area basis) declined considerably with leaf age. In addition, the percent leaf dry mass invested in trichome decreased significantly. Reductions were greater on the adaxial leaf surface, leading to an almost glabrous upper epidermis in mature leaves. Internal (i.e., leaf total minus trichome) phenolics showed no significant changes with leaf age in Eriobotrya japonica and Cydonia oblonga. In Olea europaea, however, the concentration of internal phenolics was doubled in mature leaves. Ultraviolet-B radiation resulted in a reduction of photosystem II photochemical efficiency and extensive epidermal browning only in young, dehaired leaves. No such effects were observed in young, dehaired leaves in the absence of ultraviolet-B radiation or in normal young or mature ultraviolet-B-irradiated leaves. It is suggested that the dense trichomes often covering young leaves may, in addition to other functions, protect transiently the underlying cells against ultraviolet-B radiation damage during the time period required for the maturation of internal avoidance and (or) repairing mechanisms. Key words: Cydonia oblonga, Eriobotrya japonica, Olea europaea, leaf development, leaf hairs, phenolics, ultraviolet-B radiation damage.

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.

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.

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.

scholarly journals Root endophytic fungi impact host plant biomass and respond to plant composition at varying spatio-temporal scales

2020 ◽  
Vol 44 ◽  
pp. 100907 ◽  
Author(s):  
Nathan Vannier ◽  
Anne-Kristel Bittebiere ◽  
Cendrine Mony ◽  
Philippe Vandenkoornhuyse
Keyword(s):  
Host Plant ◽  
Endophytic Fungi ◽  
Plant Biomass ◽  
Plant Composition ◽  
Temporal Scales ◽  
Root Endophytic Fungi ◽  
Spatio Temporal

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.

Consider Leaf Age Photosynthesis during Leaf Development Zdenek Sestak

BioScience ◽  
1987 ◽  
Vol 37 (10) ◽  
pp. 743-744
Author(s):  
Kenneth E. Pallett
Keyword(s):  
Leaf Development ◽  
Leaf Age
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