scholarly journals Coexistent Heteroblastic Needles of Adult Pinus canariensis C.Sm. ex DC. in Buch Trees Differ Structurally and Physiologically

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 341
Author(s):  
Beatriz Fernández-Marín ◽  
Marcos Adrián Ruiz-Medina ◽  
José Carlos Miranda ◽  
Águeda María González-Rodríguez
Keyword(s):  
Vascular Tissue ◽  
Stomatal Density ◽  
Photochemical Efficiency ◽  
Carbon Assimilation ◽  
Pinus Canariensis ◽  
Adult Transition ◽  
Needle Anatomy ◽  
Leaf Mass Area ◽  
Adult Trees ◽  
Gap Opening

Great variation in shape and size between primary (juvenile) and secondary (adult) needles, so-called leaf-heteroblasty, occurs in several Pinus species. Most of them loss primary needles during the juvenile-to-adult transition of the tree. An exception to this is Pinus canariensis (a Canary Islands endemism) in which basal resprouting twigs of adult trees frequently wear both primary and secondary needles. Taking advantage of this extraordinary study-case-species, we conducted an exhaustive comparison of both needle types through quantitative analyses of needle anatomy, photochemical performance, gas exchange, and resistance to extreme dehydration and to extreme needle temperature. We hypothesized that primary needles would show lower investment to leaf structure but higher photosynthetical efficiency. Primary needles had less stomatal density and thicker and less wettable cuticles. In cross section, primary needles showed smaller structural fraction (e.g., percent of hypodermis, endodermis and vascular tissue) and higher fraction of photosynthetic parenchyma. Significant differences between primary and secondary needles were not found in net carbon assimilation not in their leaf mass area values. Interestingly, secondary needles showed higher electron transport rate, and they were additionally much more efficient in retaining water under severe and controlled desiccant conditions. When subjected to extreme temperatures (−10° to +50 °C), primary needles recovered better their photochemical efficiency than secondary needles, after +46° and +48 °C heat-shock treatments. Our results indicate that both needle types broaden the diversity of physiological responses against environmental constrains in basal twigs of adult P. canariensis trees. Considering that this is a fire-resistant and resprouting species, this advantage could be particularly useful after a drastic environmental change such a fire or a gap opening in the forest.

scholarly journals Ecophysiological response and morphological adjustment of Argania spinosa L. Skeels under contrasting climates: case study of marginal populations

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Mohamed Ait Bihi ◽  
Fatima Ain-Lhout ◽  
Abdelhakim Hatimi ◽  
Fadma Fahmi ◽  
Saida Tahrouch
Keyword(s):  
Stomatal Density ◽  
Photochemical Efficiency ◽  
Carbon Assimilation ◽  
Distribution Area ◽  
Summer Drought ◽  
The South ◽  
Marginal Populations ◽  
Southern Limit ◽  
Argania Spinosa ◽  
The North

In this paper, we investigated the seasonal physiological performance and morphological adjustment of Argania spinosa growing under contrasting climatic and biogeographic conditions.Two marginal populations were selected in the main distribution area of the species, one at the Northwest and the other one at the South-west. Trees from the North showed a Mediterranean pattern in Photosynthetic performances, exhibiting maximal carbon assimilation during spring and minimum in summer. In contrast, trees from the South showed a different pattern with maximum values recorded in winter and minimum in spring. Photochemical efficiency of PSII results evidenced the absence of damage to PSII in both sites, probably due to an efficient energy dissipation processed by carotenoid pigments. We recorded increased LMA values in the South, which improves drought resistance. Increasing stomatal length and decreasing stomatal density were registered during the drought season in both populations. A. Spinosa is sensitive to changes in the length of drought stress at its Southern limit. The scarcity of rainfall leading to persistent drought has limited the distribution of the species to the banks of dry Wadis and depressions, where it finds some water compensations during summer. In the North, the summer drought severely impacted the species carbon assimilation.

Altitude of origin influences stomatal conductance and therefore maximum assimilation rate in Southern Beech, Nothofagus cunninghamii

2000 ◽  
Vol 27 (5) ◽  
pp. 451 ◽  
Author(s):  
Mark J. Hovenden ◽  
Tim Brodribb
Keyword(s):  
Stomatal Conductance ◽  
Stomatal Density ◽  
Carbon Assimilation ◽  
Co2 Concentration ◽  
Carboxylation Efficiency ◽  
Assimilation Rate ◽  
Carbon Assimilation Rate ◽  
Southern Beech ◽  
Maximum Stomatal Conductance ◽  
Leaf Biochemistry

Gas exchange measurements were made on saplings of Southern Beech, Nothofagus cunninghamii (Hook.) Oerst. collected from three altitudes (350, 780 and 1100 m above sea level) and grown in a common glasshouse trial. Plants were grown from cuttings taken 2 years earlier from a number of plants at each altitude in Mt Field National Park, Tasmania. Stomatal density increased with increasing altitude of origin, and stomatal con-ductance and carbon assimilation rate were linearly related across all samples. The altitude of origin influenced thestomatal conductance and therefore carbon assimilation rate, with plants from 780 m having a greater photosynthetic rate than those from 350 m. The intercellular concentration of CO2 as a ratio of external CO2 concentration (ci/ca) was similar in all plants despite the large variation in maximum stomatal conductance. Carboxylation efficiency was greater in plants from 780 m than in plants from 350 m. Altitude of origin has a strong influence on the photo-synthetic performance of N. cunninghamii plants even when grown under controlled conditions, and this influence is expressed in both leaf biochemistry (carboxylation efficiency) and leaf morphology (stomatal density).

scholarly journals Influence of High Temperature on Photosynthesis, Antioxidative Capacity of Chloroplast, and Carbon Assimilation among Heat-tolerant and Heat-susceptible Genotypes of Nonheading Chinese Cabbage

HortScience ◽  
2017 ◽  
Vol 52 (11) ◽  
pp. 1464-1470 ◽  
Author(s):  
Lingyun Yuan ◽  
Yujie Yuan ◽  
Shan Liu ◽  
Jie Wang ◽  
Shidong Zhu ◽  
...  
Keyword(s):  
High Temperature ◽  
Chinese Cabbage ◽  
Photosynthetic Capacity ◽  
Photochemical Efficiency ◽  
Membrane Integrity ◽  
Photosynthetic Apparatus ◽  
Carbon Assimilation ◽  
Light Reaction ◽  
Chlorophyll Contents ◽  
Heat Tolerant

High temperature (HT) is a major environmental stress limiting oversummer production of nonheading Chinese cabbage (NHCC, Brassica campestris ssp. chinensis Makino). In the present study, the effects of HT on photosynthetic capacity, including light reaction and carbon assimilation, were completely investigated in two NHCC, ‘xd’ (heat-tolerant), and ‘sym’ (heat-susceptible). The two genotypes showed significant differences in plant morphology, photosynthetic capacity, and photosynthate metabolism (carboassimilation). HT caused a decrease in photosynthesis, chlorophyll contents, and photochemical activity in NHCC. However, these main photosynthetic-related parameters, including net photosynthetic rate (PN), maximal photochemical efficiency of PSII (Fv/Fm), and total chlorophyll content in ‘xd’, were significantly higher than those of ‘sym’ plants. The antioxidant contents and antioxidative enzyme activities of ascorbic acid-reduced glutathione cycle in the chloroplast of ‘xd’ were significantly higher than those of ‘sym’. Microscopic analyses revealed that HT affected the structure of photosynthetic apparatus and membrane integrity to a different extent, whereas ‘xd’ could maintain a better integrated chloroplast shape and thylakoid. Inhibited light reaction also hampered carbon assimilation, resulting in a decline of carboxylation efficiency and imbalance of carbohydrate metabolism. However, larger declined extents in these data were presented in ‘sym’ (heat-susceptible) than ‘xd’ (heat-tolerant). The heat-tolerant genotype ‘xd’ had a better capacity for self-protection by improved light reaction and carbon assimilation responding to HT stress.

scholarly journals Growth, leaf and stomatal traits of crabwood (Carapa guianensis Aubl.) in central Amazonia

2012 ◽  
Vol 36 (1) ◽  
pp. 07-16 ◽  
Author(s):  
Miguel Angelo Branco Camargo ◽  
Ricardo Antonio Marenco
Keyword(s):  
Growth Rates ◽  
Stomatal Density ◽  
Leaf Gas Exchange ◽  
Carbon Assimilation ◽  
Leaf Traits ◽  
Leaf Thickness ◽  
Diurnal Changes ◽  
Wet Season ◽  
Carapa Guianensis ◽  
Rainfall Seasonality

Crabwood (Carapa guianensis Aubl.) is a fast growing tree species with many uses among Amazonian local communities. The main objective of this study was to assess the effect of seasonal rainfall pattern on growth rates, and seasonal and diurnal changes in leaf gas exchange and leaf water potential (ΨL) in crabwood. To assess the effect of rainfall seasonality on growth and physiological leaf traits an experiment was conducted in Manaus, AM (03º 05' 30" S, 59º 59' 35" S). In this experiment, six 6-m tall plants were used to assess photosynthetic traits and ΨL. In a second experiment the effect of growth irradiance on stomatal density (S D), size (S S) and leaf thickness was assessed in 0.8-m tall saplings. Stomatal conductance (g s) and light-saturated photosynthesis (Amax) were higher in the wet season, and between 09:00 and 15:00 h. However, no effect of rainfall seasonality was found on ΨL and potential photosynthesis (CO2-saturated). ΨL declined from -0.3 MPa early in the morning to -0.75 MPa after midday. It increased in the afternoon but did not reach full recovery at sunset. Growth rates of crabwood were high, and similar in both seasons (2 mm month-1). Leaf thickness and S D were 19% and 47% higher in sun than in shade plants, whereas the opposite was true for S S. We conclude that ΨL greatly affects carbon assimilation of crabwood by reducing g s at noon, although this effect is not reflected on growth rates indicating that other factors offset the effect of g s on Amax.

scholarly journals Local adaptation optimizes photoprotection strategies in a Neotropical legume tree under drought stress

2021 ◽  
Author(s):  
Irene Cordero ◽  
María Dolores Jiménez ◽  
Juan Antonio Delgado ◽  
Luis Balaguer ◽  
José J Pueyo ◽  
...  
Keyword(s):  
Local Adaptation ◽  
Water Availability ◽  
Light Stress ◽  
Photochemical Efficiency ◽  
Carbon Assimilation ◽  
Common Garden ◽  
Thermal Dissipation ◽  
Functional Ecology ◽  
Evaporative Demand ◽  
Legume Tree

Abstract Photoprotection is a plant functional mechanism to prevent photooxidative damage by excess light. This is most important when carbon assimilation is limited by drought, and as such, it entails a trade-off between carbon assimilation vs stress avoidance. The ecological adaptation of plants to local water availability can lead to different photoprotective strategies. To test this, we used different provenances of Caesalpinia spinosa (Mol.) Kuntze (commonly known as ‘tara’) along a precipitation gradient. Tara is a Neotropical legume tree with high ecological and commercial value, found in dry tropical forests, which are increasingly threatened by climate change. Morphological and physiological responses of tara provenances were analysed under three different treatments of drought and leaflet immobilization, i.e., light stress, in a common garden greenhouse experiment. Tara quickly responded to drought by reducing stomatal conductance, evapotranspiration, photochemical efficiency, carbon assimilation and growth, while increasing structural and chemical photoprotection (leaflet angle and pigments for thermal dissipation). Leaflet closure was an efficient photoprotection strategy with overall physiological benefits for seedlings as it diminished the evaporative demand and avoided photodamage, but also entailed costs by reducing net carbon assimilation opportunities. These responses depended on seed origin, with seedlings from the most xeric locations showing the highest dehydration tolerance, suggesting local adaptation and highlighting the value of different strategies under distinct environments. This plasticity in its response to environmental stress allows tara to thrive in locations with contrasting water availability. Our findings increase the understanding of the factors controlling the functional ecology of tara in response to drought, which can be leveraged to improve forecasts of changes in its distribution range, and for planning restoration projects with this keystone tree species.

scholarly journals Deepening Rooting Depths Improve Plant Water and Carbon Status of a Xeric Tree during Summer Drought

Forests ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 592
Author(s):  
Xin-Jun Zheng ◽  
Gui-Qing Xu ◽  
Yan Li ◽  
Xue Wu
Keyword(s):  
Water Status ◽  
Photochemical Efficiency ◽  
Small Diameter ◽  
Stem Diameter ◽  
Physiological Traits ◽  
Rooting Depth ◽  
Summer Drought ◽  
Mortality Pattern ◽  
Adult Trees ◽  
Diameter Classes

Exploring the effects of drought on trees of different sizes is an important research topic because the size-dependent mortality pattern of the major dominant species significantly affects the structure and function of plant communities. Here we studied the physiological performance and non-structural carbohydrates (NSCs) dynamics of a small xeric tree species, Haloxylon ammodendron (C.A.Mey.) of different tree size with varying rooting depth, during summer drought. We measured predawn (Ψpd) and midday (Ψm) leaf water potential, osmotic potential at saturated turgor (π100), and turgor lost point (Ψtlp), stomatal conductance (gs) at noon, maximum photochemical efficiency of photosystem II (Fv/Fm) in the morning, and NSCs concentration, from June–September. Our results demonstrated that the summer drought reduces the overall performance of physiological traits of the small young trees more than the larger adult trees. Ψpd, gs and Fv/Fm dropped larger in the small-diameter groups than the larger diameter groups. Substantial osmotic adjustments were observed in small size individuals (with lower π100 and Ψtlp) to cope with summer drought. Furthermore, mean concentration of NSCs for the leaf and shoot were higher in September than in July in every basal stem diameter classes suggested the leaf and shoot acted as reserve for NSC. However the root NSCs concentrations within each basal stem diameter class exhibited less increase in September than in the July. At the same time, the small young tress had lower root NSCs concentrations than the larger adult tree in both July and September. The contrasting root NSC concentrations across the basal stem diameter classes indicated that the roots of smaller trees may be more vulnerable to carbon starvation under non-lethal summer drought. The significant positive relationship between rooting depth and physiological traits & root NSCs concentration emphasize the importance of rooting depth in determining the seasonal variation of water status, gas exchange and NSCs.

Incontinence in aging leaves: deteriorating water relations with leaf age in Agastachys odorata (Proteaceae), a shrub with very long-lived leaves

2007 ◽  
Vol 34 (10) ◽  
pp. 918 ◽  
Author(s):  
Gregory J. Jordan ◽  
Timothy J. Brodribb
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Stomatal Density ◽  
Leaf Age ◽  
Carbon Assimilation ◽  
Leaf Damage ◽  
Evergreen Species ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency ◽  
Cuticle Thickness

This paper examines physiological characteristics of the leaves of Agastachys odorata R.Br., a wet-climate sclerophyllous shrub with very long-lived leaves. It addresses the hypothesis that cuticles become leakier to water vapour as leaves age. Astomatous cuticular conductance, whole-leaf minimum epidermal conductance, leaf damage and accumulation of epiphylls all increased several-fold with leaf age from first year growth to 10 years of age. Maximum carbon assimilation peaked 1 year after full leaf expansion, then declined. Intrinsic water use efficiency was highest in mid-aged leaves and declined markedly in the oldest leaves. Stomatal density, stomatal size and cuticle thickness did not vary significantly among ages. The older leaves were less effective at controlling water loss, resulting in decreases in water use efficiency. A differential increase in the conductance of the stomatal surface of the leaves relative to astomatous surface suggested that stomatal leakiness was significant in leaves over five years old. Although data for other species is ambiguous, the deterioration in A. odorata appears to be consistent with changes in the oldest leaves of other species. Thus, decreasing ability to use water efficiently appears to be a consequence of accumulated damage and may contribute to the need for leaf senescence in evergreen species with little self shading.

Stomatal and photochemical limitations of photosynthesis in coffee (Coffea spp.) plants subjected to elevated temperatures

2018 ◽  
Vol 69 (3) ◽  
pp. 317 ◽  
Author(s):  
Weverton P. Rodrigues ◽  
Jefferson R. Silva ◽  
Luciene S. Ferreira ◽  
José A. Machado Filho ◽  
Fabio A. M. M. A. Figueiredo ◽  
...  
Keyword(s):  
High Temperature ◽  
Elevated Temperatures ◽  
Stomatal Density ◽  
Stomatal Closure ◽  
Carbon Assimilation ◽  
Field Capacity ◽  
Photosynthetic Performance ◽  
Potted Plants ◽  
Intrinsic Water Use Efficiency ◽  
Mild Temperature

Temperature increase assumes a prominent role in the context of expected climate change because of its significant impact on plant metabolism. High temperature can affect the carbon-assimilation pathway at both stomatal and non-stomatal levels, mainly through stomatal closure and photochemical and biochemical limitations. In general, however, plants have some ability to trigger acclimation mechanisms to cope with stressful conditions, especially if the limitations are imposed in a gradual manner during seasonal change. This study aims at evaluating changes at stomatal and photochemical levels in Coffea arabica and C. canephora under exposure to mild temperature (spring) and high temperature (summer). Potted plants were maintained in a greenhouse, watered to field capacity and subject to natural variations of light, temperature and relative humidity. In C. arabica, exposure to summer conditions decreased photosynthetic rates (A), stomatal conductance (gs) and stomatal density and increased intrinsic water-use efficiency (iWUE) compared with spring values, whereas C. canephora plants maintained similar values in both seasons. However, C. canephora presented lower A and gs during spring than C. arabica. Because photosynthetic capacity (Amax), photosynthetic performance index and membrane permeability were similar between genotypes and seasons, and maximum quantum yield (Fv/Fm) and photosynthetic pigments were not affected in C. arabica in summer, we conclude that under high temperature conditions, stomatal closure imposes the major limitation on C. arabica photosynthesis in summer. Finally, both coffee genotypes were able to avoid damage to photochemistry pathway under supra-optimal temperatures.

scholarly journals Effects of drought on needle anatomy of Pinus canariensis

Flora ◽  
2004 ◽  
Vol 199 (2) ◽  
pp. 85-89 ◽  
Author(s):  
Dieter Grill ◽  
Michael Tausz ◽  
U.t.e. Pöllinger ◽  
Maria Soledad Jiménez ◽  
Domingo Morales
Keyword(s):  
Pinus Canariensis ◽  
Needle Anatomy ◽  
Effects Of Drought

Variability of leaf stomatal density of adult trees ofArgania spinosa(L.) Skeels in the field

2005 ◽  
Vol 152 (3) ◽  
pp. 281-288 ◽  
Author(s):  
Fouzia Bani-Aameur ◽  
Abdelaziz Zahidi
Keyword(s):  
Stomatal Density ◽  
Adult Trees
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