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Start Over Subject mesophyll

1. Anatomical and eco-physiological changes in leaves of couch-grass (Elymus repens L.), a temperate loess grassland species, after 7 years growth under elevated CO2 concentration

Creator:
Engloner, A. I., Kovács, D., Balogh, J., and Tuba, Z.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
mesophyll, net photosynthetic rate, phloem, sclerenchyma, stomatal conductance, stomatal density, tracheary, transpiration rate, and water use efficiency
Language:
Multiple languages
Description:
Leaf anatomy and eco-physiology of Elymus repens, a temperate loess grassland species, were determined after seven years of exposure to 700 μmol (CO2) mol-1 (EC). EC treatment resulted in significant reduction of stomatal density on both surfaces of couch-grass leaves. Thickness of leaves and that of the sclerenchyma tissues between the vessels and the adaxial surfaces, the area of vascular bundle, and the volumes of phloem and tracheary increased at EC while abaxial epidermis and the sclerenchyma layer between the vessel and the abaxial surface were thicker at ambient CO2 concentration (AC). Stomatal conductance and transpiration rates were lower in EC, while net CO2 assimilation rate considerably increased at EC exposure. Contents of soluble sugars and starch were higher in EC-treated couch-grass leaves than in plants grown at AC. and A. I. Engloner ... [et al.].
Rights:
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2. Changes in chloroplast morphology of different parenchyma cells in leaves of Haberlea rhodopensis Friv. during desiccation and following rehydration

Creator:
Nagy-Déri, H., Péli, E. R., Georgieva, K., and Tuba, Z.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, chloroplast, dessication tolerance, homoiochlorophyllous, mesophyll, palisade parenchyma, and spongy parenchyma
Language:
Multiple languages
Description:
The size, shape, and number of chloroplasts in the palisade and spongy parenchyma layers of Haberlea rhodopensis leaves changed significantly during desiccation and following rehydration. The chloroplasts became smaller and more rounded during desiccation, and aggregated in the middle of the cell. The size and number of chloroplasts in the palisade parenchyma cells were higher than in spongy parenchyma. The good correlation observed between the size or number of chloroplasts and the cross-sectional area of mesophyll cells, the cross-sectional width of the leaf and its water content suggested that the palisade cells were more responsive to water availability than the spongy cells. Changes in chloroplast number during desiccation and rehydration process are characteristic features for desiccation-tolerant plants (especially in homoiochlorophyllous strategy). and H. Nagy-Déri ... [et al.].
Rights:
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3. Combined effects of elevated CO2 concentration and drought stress on photosynthetic performance and leaf structure of cucumber (Cucumis sativus L.) seedlings

Creator:
Liu, B. B., Li, M., Li, Q. M., Cui, Q. Q., Zhang, W. D., Ai, X. Z., and Bi, H. G.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
abiotické faktory, chloroplasty, elektronová mikroskopie, abiotic factors, chloroplasts, electron microscopy, mezofyl, akumulace škrobu, stomata, mesophyll, starch accumulation, 2, and 581
Language:
Multiple languages
Description:
Drought stress is one of the main environmental factors limiting plant growth and productivity of many crops. Elevated carbon dioxide concentration (eCO2) can ameliorate, mitigate, or compensate for the negative impact of drought on plant growth and enable plants to remain turgid and functional for a longer period. In order to investigate the combined effects of eCO2 and drought stress on photosynthetic performance and leaf structures, we analyzed photosynthetic characteristics and structure and ultrastructure of cucumber leaves. The decline in net photosynthetic rate under moderate drought stress occurred due to stomatal limitation alone, while under severe drought stress, it was the result of stomatal and nonstomatal limitations. Conversely, eCO2 improved photosynthetic performance under moderate drought stress, increased the lengths of the palisade cells and the number of chloroplasts per palisade cell under severe drought stress, and significantly increased the grana thickness under moderate drought stress. Additionally, eCO2 significantly decreased stomatal density, stomatal widths and stomatal aperture on the abaxial surface of leaves under moderate drought stress. In conclusion, eCO2 can alleviate the negative effects of drought stress by improving the drought resistance of cucumber seedlings through stomatal modifications and leaf structure., B. B. Liu, M. Li, Q. M. Li, Q. Q. Cui, W. D. Zhang, X. Z. Ai, H. G. Bi., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

4. Leaf anatomy and photosynthetic acclimation in Valeriana jatamansi L. grown under high and low irradiance

Creator:
Pandey, S. and Kushwaha, R.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
chlorophyll, chloroplast, leaf thickness, mesophyll, photosynthetic acclimation, respiration rate, and shade
Language:
Multiple languages
Description:
Relationship of leaf anatomy with photosynthetic acclimation of Valeriana jatamansi was studied under full irradiance [FI, 1 600 μmol(PPFD) m-2 s-1] and net-shade [NS, 650 μmol(PPFD) m-2 s-1]. FI plants had thicker leaves with higher respiration rate (RD), nitrogen content per unit leaf area, chlorophyll a/b ratio, high leaf mass per leaf area unit (LMA), and surface area of mesophyll cell (Smes) and chloroplasts (Sc) facing intercellular space than NS plants. The difference between leaf thickness of FI and NS leaves was about 28 % but difference in photon-saturated rate of photosynthesis per unit leaf area (PNmax) was 50 %. This indicates that PNmax can increase to a larger extent than the leaf thickness with increasing irradiance in V. jatamansi. Anatomical studies showed that the mesophyll cells of FI plants had no open spaces along the mesophyll cell walls (higher Sc), but in NS plants wide open spaces along the mesophyll cell wall (lower Sc) were found. Positive correlation between Sc and PNmax explained the higher PNmax in FI plants. Increase in mesophyll thickness increased the availability of space along the mesophyll cell wall for chloroplasts (increased Sc) and hence PNmax was higher in FI plants. Thus this Himalayan species can acclimate to full sunlight by altering leaf anatomy and therefore may be cultivated in open fields. and S. Pandey, R. Kushwaha.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

5. Morpho-anatomical and physiological leaf traits of two alpine herbs, Podophyllum hexandrum and Rheum emodi in the Western Himalaya under different irradiances

Creator:
Pandey, S., Kumar, N., and Kushwaha, R.
Format:
electronic, bez média, and svazek
Type:
model:article and TEXT
Subject:
alpine plants, leaf anatomy, leaf unit per unit leaf area, leaf physiology, mesophyll, net photosynthetic rate, and ribulose-1,5-bisphosphate carboxylase, oxygenase
Language:
Multiple languages
Description:
Morpho-anatomical leaf traits and photosynthetic activity of two alpine herbs, Podophyllum hexandrum (shade-tolerant) and Rheum emodi (light-requiring), were studied under field (PAR>2 000 µmol m-2 s-1) and greenhouse (PAR 500 µmol m-2 s-1) conditions. Mesophyll thickness, surface area of mesophyll cells facing intercellular spaces (Smes), surface area of chloroplasts facing intercellular spaces (Sc), intercellular spaces of mesophyll cells (porosity), photon-saturated rate of photosynthesis per unit leaf area (PNmax), and ribulose-1,5-bisphosphate carboxylase/oxygenase activity decreased in the greenhouse with respect to the field and the decreases were significantly higher in R. emodi than in P. hexandrum. P. hexandrum had lower intercellular CO2 concentration than R. emodi under both irradiances. The differences in acclimation of the two alpine herbs to low irradiance were due to their highly unlikely changes in leaf morphology, anatomy, and PNmax which indicated that the difference in radiant energy requirement related to leaf acclimation had greater impact under low than high irradiance. and S. Pandey, N. Kumar, R. Kushwaha.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

6. Morphoanatomy and ecophysiology of tree seedlings in semideciduous forest during high-light acclimation in nursery

Creator:
Calzavara, A. K., Bianchini, E., Mazzanatti, T., Oliveira, H. C., Stolf-Moreira, R., and Pimenta, J. A.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, ecological anatomy, environmental restoration, mesophyll, plant ecophysiology, 2, and 581
Language:
Multiple languages
Description:
a1_The recomposition of deforested environments demands the acclimation of seedlings in nurseries. This process induces changes in physiological, anatomical, and morphological traits of plants, favouring their establishment after transplantation to the field. The present study aimed to verify the influence of full-sun acclimation on seedling hardiness. For the purpose, leaf gas-exchange, plant anatomical and morphological parameters of three tree species [Ceiba speciosa (A. St.-Hil.) Ravenna (Malvaceae), Croton floribundus Spreng. (Euphorbiaceae), and Cecropia pachystachya Trecul (Urticaceae)], which are used for reforestation in the Brazilian Atlantic biome, were evaluated. Seedlings were grown under 40% of total PPFD (shaded control) and under full sun (acclimated) for 168 days. The acclimation process induced a higher leaf production rate in C. speciosa and C. floribundus, whereas C. pachystachya seedlings replaced their leaves quickly, irrespective of the light conditions. The newly developed leaves of all three species presented a lower area and thicker palisade parenchyma, resulting in a reduced specific leaf area. The seedlings of C. speciosa and C. pachystachya showed increases in light-saturated net photosynthesis and transpiration rates, whereas water-use efficiency generally remained unchanged in all three species. The full-sun acclimated seedlings of C. pachystachya showed a reduced relative growth rate, lower height/stem diameter (H/D) and shoot to root dry mass ratios, characteristics that may result in greater physical resistance and ability for water and nutrient uptake to support the higher transpiratory demand under full sun. The reduction of the H/D ratio also occurred in the acclimated seedlings of C. speciosa., a2_The seedlings of C. floribundus showed few changes during acclimation, but they did not seem to be affected by excessive light. In spite of the observed differences among the three species, all of them developed hardiness characteristics, mainly related to leaf anatomy, which should favour their establishment after transplantation to the field., A. K. Calzavara, E. Bianchini, T. Mazzanatti, H. C. Oliveira, R. Stolf-Moreira, J. A. Pimenta., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

7. Photosynthetic performance and water use efficiency of the fern Cheilanthes persica

Creator:
Gratani, L., Crescente, M. F., and Rossi, G.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
carotenoids, chlorophyll, cuticle, dehydration, desiccation tolerance, mesophyll, palisade and spongy parenchyma, stomatal conductance, and succulence
Language:
Multiple languages
Description:
Morphological, anatomical and physiological frond traits of Cheilanthes persica (Bory) Mett. ex Kuhn were studied to analyze its adaptive strategy. Mean frond life span is about 340 d. Mature fronds are characterized by 91 g m-2 areal dry mass (ADM) and 217 g m-2 succulence. The reduction of frond water content in July (dehydration phase) caused a 51 % decrease in frond surface area (SA). Fronds were dry in August (desiccation phase); nevertheless, in September they showed an increased SA (rehydration phase). Chlorophyll (Chl) a/b ratio, above 3, and the well developed palisade parenchyma (two layers, total thickness of 103.9 µm) are typical for sun leaves. Chl and carotenoid contents and net photosynthetic rate (PN) increased during frond development until the highest values in April-May (maturity phase). When mean air temperature reached 31.3 °C, stomatal conductance (gs) decreased by 34 % and PN by 33 %. The high pigment contents can dissipate the excess of radiant energy, particularly under unfavourable conditions, when PN is low. Rather high PN was found during the rehydration stage. The pronounced decline of mesophyll activity during the declining phase was confirmed by the lowest PN. and L. Gratani, M. F. Crescente, G. Rossi.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

8. Photosynthetically versatile thin shade leaves: A paradox of irradiance-response curves

Creator:
Tateno, M. and Taneda, H.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
construction cost, dark respiration rate, mesophyll, Morus, mulberry, net photosyntheic rate, and photosyntetically active radiation
Language:
Multiple languages
Description:
Thick sun leaves have a larger construction cost per unit leaf area than thin shade leaves. To re-evaluate the adaptive roles of sun and shade leaves, we compared the photosynthetic benefits relative to the construction cost of the leaves. We drew photosynthetically active radiation (PAR)-response curves using the leaf-mass-based photosynthetic rate to reflect the cost. The dark respiration rates of the sun and shade leaves of mulberry (Morus bombycis Koidzumi) seedlings did not differ significantly. At irradiances below 250 µmol m-2 s-1, the shade leaves tended to have a significantly larger net photosynthetic rate (PN) than the sun leaves. At irradiances above 250 µmol m-2 s-1, the PN did not differ significantly. The curves indicate that plants with thin shade leaves have a larger daily CO2 assimilation rate per construction cost than those with thick sun leaves, even in an open habitat. These results are consistently explained by a simple model of PAR extinction in a leaf. We must target factors other than the effective assimilation when we consider the adaptive roles of thick sun leaves. and M. Tateno, H. Taneda.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

9. Physiological and ultrastructural responses of sour orange (Citrus aurantium L.) clones to water stress

Creator:
Ben Salem-Fnayou, A. , Belghith, I., Lamine, M., Mliki, A., and Ghorbel, A.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
biomasa, chloroplasty, zavlažování, biomass, chloroplasts, ultrastruktura chloroplastu, výměna plynu, sucho, klony, mezibuněčná koncentrace CO2, list, chloroplast ultrastructure, gas exchange, drought, avoidance strategy, Cleopâtra mandarin, clones, indol-butyric acid, irrigation, intercellular CO2 concentration, leaf, mesophyll, 2, and 581
Language:
Multiple languages
Description:
Water stress is a major abiotic constraint leading to serious crop losses. Recently, in the Mediterranean region, water stress has become markedly sensed, especially in Citrus orchards. This study investigated the physiological responses of local sour orange (Citrus aurantium L.) clones to severe water stress. Water stress was applied by withholding irrigation during weeks, followed by a rewatering phase during three months. Under water stress, sour orange clones decreased their stomatal conductance, net photosynthetic rate, and transpiration rate. On the contrary, biomass was stable, especially in the Kliaa clone. In addition, reduced leaf water potentials (-3 MPa) and water contents were measured in most of the clones, except Kliaa which kept the highest water potential (-2.5 MPa). After rewatering, all clones recovered except of the Ghars Mrad (GM) clone. Ultrastructural observations of leaf sections by transmission electron microscopy did not reveal marked alterations in the mesophyll cells and chloroplast structure of Kliaa in comparison to the sensitive clone GM, in which palisade parenchyma cells and chloroplasts were disorganized. This contrasting behavior was mainly attributed to genetic differences as attested by molecular analysis. This study highlighted GM as the drought-sensitive clone and Kliaa as the tolerant clone able to develop an avoidance strategy based on an efficient stomatal regulation. Although a high percentage of polyembryony characterizes C. aurantium and justifies its multiplication by seeds, heterogeneous water-stress responses could be observed within sour orange plants in young orchards., A. Ben Salem-Fnayou, I. Belghith, M. Lamine, A. Mliki, A. Ghorbel., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public