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 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 The Impact of Phloem Feeding Insects on Leaf Ecophysiology Varies With Leaf Age

2021 ◽  
Vol 12 ◽  
Author(s):  
Sylvain Pincebourde ◽  
Jérôme Ngao
Keyword(s):  
Growth Rate ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Carbon Content ◽  
Nitrogen Content ◽  
Leaf Gas Exchange ◽  
Leaf Age ◽  
Leaf Nitrogen Content ◽  
Gas Exchanges ◽  
Young Leaves

Herbivore insects have strong impacts on leaf gas exchange when feeding on the plant. Leaf age also drives leaf gas exchanges but the interaction of leaf age and phloem herbivory has been largely underexplored. We investigated the amplitude and direction of herbivore impact on leaf gas exchange across a wide range of leaf age in the apple tree–apple green aphid (Aphis pomi) system. We measured the gas exchange (assimilation and transpiration rates, stomatal conductance and internal CO2 concentration) of leaves infested versus non-infested by the aphid across leaf age. For very young leaves up to 15 days-old, the gas exchange rates of infested leaves were similar to those of non-infested leaves. After few days, photosynthesis, stomatal conductance and transpiration rate increased in infested leaves up to about the age of 30 days, and gradually decreased after that age. By contrast, gas exchanges in non-infested leaves gradually decreased across leaf age such that they were always lower than in infested leaves. Aphids were observed on relatively young leaves up to 25 days and despite the positive effect on leaf photosynthesis and leaf performance, their presence negatively affected the growth rate of apple seedlings. Indeed, aphids decreased leaf dry mass, leaf surface, and leaf carbon content except in old leaves. By contrast, aphids induced an increase in leaf nitrogen content and the deviation relative to non-infested leaves increased with leaf age. Overall, the impacts of aphids at multiple levels of plant performance depend on leaf age. While aphids cause an increase in some leaf traits (gas exchanges and nitrogen content), they also depress others (plant growth rate and carbon content). The balance between those effects, as modulated by leaf age, may be the key for herbivory mitigation in plants.

scholarly journals Normal Cyclic Variation in CO2 Concentration in Indoor Chambers Decreases Leaf Gas Exchange and Plant Growth

Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 663
Author(s):  
James Bunce
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Leaf Gas Exchange ◽  
Genetic Material ◽  
Co2 Concentration ◽  
Cyclic Variation ◽  
Indoor Exposure ◽  
Elevated Atmospheric Co2 ◽  
Gas Exchange System ◽  
Opening And Closing

Attempts to identify crop genetic material with larger growth stimulation at projected elevated atmospheric CO2 concentrations are becoming more common. The probability of reductions in photosynthesis and yield caused by short-term variation in CO2 concentration within elevated CO2 treatments in the free-air CO2 enrichment plots raises the question of whether similar effects occur in glasshouse or indoor chamber experiments. These experiments were designed to test whether even the normal, modest, cyclic variation in CO2 concentration typical of indoor exposure systems have persistent impacts on photosynthesis and growth, and to explore mechanisms underlying the responses observed. Wheat, cotton, soybeans, and rice were grown from seed in indoor chambers at a mean CO2 concentration of 560 μmol mol−1, with “triangular” cyclic variation with standard deviations of either 4.5 or 18.0 μmol mol−1 measured with 0.1 s sampling periods with an open path analyzer. Photosynthesis, stomatal conductance, and above ground biomass at 20 to 23 days were reduced in all four species by the larger variation in CO2 concentration. Tests of rates of stomatal opening and closing with step changes in light and CO2, and tests of responses to square-wave cycling of CO2 were also conducted on individual leaves of these and three other species, using a leaf gas exchange system. Reduced stomatal conductance due to larger amplitude cycling of CO2 during growth occurred even in soybeans and rice, which had equal rates of opening and closing in response to step changes in CO2. The gas exchange results further indicated that reduced mean stomatal conductance was not the only cause of reduced photosynthesis in variable CO2 conditions.

scholarly journals LEAF GAS EXCHANGE CHARACTERISTICS OF FOUR PAPAYA GENOTYPES DURING DIFFERENT STAGES OF DEVELOPMENT

2001 ◽  
Vol 23 (3) ◽  
pp. 522-525 ◽  
Author(s):  
ELIEMAR CAMPOSTRINI ◽  
OSVALDO KIYOSHI YAMANISHI ◽  
CARLOS A. MARTINEZ
Keyword(s):  
Gas Exchange ◽  
Carica Papaya ◽  
Leaf Gas Exchange ◽  
Carbon Dioxide Concentration ◽  
Field Capacity ◽  
Experimental Period ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Loam Soil ◽  
Gas Exchange Characteristics

In this research, was used four papaya (Carica papaya L.) genotypes: three from the 'Solo ( Sunrise Solo TJ, Sunrise Solo 72/12 and Baixinho de Santa Amália) group and one from the 'Formosa' group (Know-You 01). They were grown in plastic pots containing a sandy-clay-loam soil subjected to pH correction and fertilization, under greenhouse conditions. Throughout the experimental period plants were subjected to periodic irrigation to maintain the soil humitidy around field capacity. The experiment was conducted 73 days after sowing. In all genotypes, leaf gas exchange characteristics were determined. The net photosynthetic rate (A, mumol m-2 s-1 ), stomatal conductance (g s mol m-2 s-1), leaf temperature (T I, 0C) and intercellular carbon dioxide concentration (ci, muL L-1) on the 4th, 5th, 6th, 7th, 8th and 9th leaves from the plant apex were determined. No significant differences were observed for A, g s, c i, or Tl either among the leaves sampled from any of the genotypes. A was positively correlated with g s and in the other hand T I and g s were negatively correlated. The results suggest that, for 73 DAP, all the sampled papaya leaves functioned as sources of organs.

Soybean Leaf Gas‐Exchange Responses to Carbon Dioxide and Water Stress

1994 ◽  
Vol 86 (4) ◽  
pp. 625-636 ◽  
Author(s):  
L. H. Allen ◽  
R. R. Valle ◽  
J. W. Mishoe ◽  
J. W. Jones
Keyword(s):  
Carbon Dioxide ◽  
Water Stress ◽  
Gas Exchange ◽  
Leaf Gas Exchange ◽  
Soybean Leaf

Osmotic Adjustment: Effect of Water Stress on Carbohydrates in Leaves, Stems and Roots of Apple

1995 ◽  
Vol 22 (5) ◽  
pp. 747 ◽  
Author(s):  
Z Wang ◽  
B Quebedeaux ◽  
GW Stutte
Keyword(s):  
Water Stress ◽  
Osmotic Adjustment ◽  
Sucrose Concentration ◽  
Starch Content ◽  
Soluble Carbohydrates ◽  
Soluble Carbohydrate ◽  
Malus Domestica Borkh ◽  
Mature Leaves ◽  
Young Leaves ◽  
Response To Water

Potted apple (Malus domestica Borkh. cv. Jonathan) trees were subjected to water stress in a greenhouse. Midday leaf water potential (ΨW), osmotic potential (ΨS), soluble carbohydrates, and starch content of expanding and mature leaves, stems, and roots were measured to determine whether active osmotic adjustment occurred and if water stress affected carbohydrate metabolism. Mature leaves had the highest total soluble carbohydrate level (357 mM) and lowest Ψ (-1.85 MPa), followed by young leaves (278 mM, -1.58 MPa), stems (115 mM, -1.02 MPa), and roots (114 mM, -0.87 MPa). Sorbitol was the major component in all organs ranging from 53% of total soluble carbohydrate in young leaves to 73% in mature leaves. When ΨW decreased from -1.0 to -3.2 MPa, active osmotic adjustments of 0.3-0.4 MPa were observed in mature leaves, stems, and roots while a significantly higher adjustment of 1.0 MPa was detected in young leaves 5 days after the initiation of water stress. Sorbitol levels in leaves and stems gradually increased as ΨW decreased from -1.0 to -2.5 MPa, and then remained relatively stable or decreased slightly as ΨW decreased from -2.5 to -3.2 MPa. However, the percentage of soluble carbohydrate as sorbitol in roots decreased in response to water stress. Sucrose concentration decreased in mature leaves and stems, but increased in young leaves and roots as ΨW decreased. Starch concentrations in stems and roots also decreased as water stress developed. The sorbitol to sucrose ratios increased in mature leaves, but decreased in roots in response to water stress.

scholarly journals The impact of winter flooding with saline water on foliar carbon uptake and the volatile fraction of leaves and fruits of lemon (Citrus×limon) trees

2012 ◽  
Vol 39 (3) ◽  
pp. 199 ◽  
Author(s):  
Violeta Velikova ◽  
Tommaso La Mantia ◽  
Marco Lauteri ◽  
Marco Michelozzi ◽  
Isabel Nogues ◽  
...  
Keyword(s):  
Saline Water ◽  
Intercellular Co2 Concentration ◽  
Co2 Concentration ◽  
Volatile Fraction ◽  
Citrus Limon ◽  
Young Leaves ◽  
Quality Water ◽  
Winter Flooding ◽  
The Impact ◽  
Intercellular Co2

We investigated the consequences of recurrent winter flooding with saline water on a lemon (Citrus × limon (L.) Burm.f.) orchard, focussing on photosynthesis limitations and emission of secondary metabolites (isoprenoids) from leaves and fruits. Measurements were carried out immediately after flooding (December), at the end of winter (April) and after a dry summer in which plants were irrigated with optimal quality water (September). Photosynthesis was negatively affected by flooding. The effect was still visible at the end of winter, whereas the photosynthetic rate was fully recovered after summer, indicating an unexpected resilience capacity of flooded plants. Photosynthesis inhibition by flooding was not due to diffusive limitations to CO2 entry into the leaf, as indicated by measurements of stomatal conductance and intercellular CO2 concentration. Biochemical and photochemical limitations seemed to play a more important role in limiting the photosynthesis of flooded plants. In young leaves, characterised by high rates of mitochondrial respiration, respiratory rates were enhanced by flooding. Flooding transiently caused large and rapid emission of several volatile isoprenoids. Emission of limonene, the most abundant compound, was stimulated in the leaves, and in young and mature fruits. Flooding changed the blend of emitted isoprenoids, but only few changes were observed in the stored isoprenoids pool.

Regulation of Carboxylation and Photosynthetic Oscillations During Sun-Shade Acclimation in Helianthus annuus Measured With a Rapid-Response Gas Exchange System

1988 ◽  
Vol 15 (2) ◽  
pp. 239 ◽  
Author(s):  
CB Osmond ◽  
V Oja ◽  
A Laisk
Keyword(s):  
Gas Exchange ◽  
Intercellular Co2 Concentration ◽  
Photosynthetic Apparatus ◽  
Co2 Concentration ◽  
Rapid Response ◽  
Exchange System ◽  
Dynamic Regulation ◽  
Bisphosphate Carboxylase ◽  
Shade Acclimation ◽  
Gas Exchange System

The consequences of acclimation from shade to sun and vice versa for regulated photosynthetic metabolism were examined in H. annuus. A rapid-response gas exchange system was used to assess changes in carboxylation-related parameters (mesophyll conductance, assimilatory charge and CO2 capacity) and to analyse oscillations in CO2 fixation following transfer to high CO2 concentration as a function of intercellular CO2 concentration and light intensity. Data showed a two- to threefold change in all carboxylation-related parameters during acclimation in either direction. Dynamic regulation of carboxylation, indicated by changes in oscillatory response as a function of CO2 concentration at light saturation, remained unchanged, consistent with concerted regulation of ribulose-1,5-bisphosphate carboxylase-oxygenase during acclimation. However, the light dependency of oscillations changed during acclimation from shade to sun, and the range of oscillation was closely tied to the maximum rate of steady-state photosynthesis at CO2 saturation. These data imply that changes in the light-absorbing and electron transport components of the photosynthetic apparatus underlie the shift in regulatory behaviour during acclimation.

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