scholarly journals Stomatal density, leaf area and plant size variation of Rhizophora mangle (Malpighiales: Rhizophoraceae) along a salinity gradient in the Mexican Caribbean

2017 ◽  
Vol 65 (2) ◽  
Author(s):  
Joanne R. Peel ◽  
Maria C. Mandujano Sanchez ◽  
Jorge Lopez Portillo ◽  
Jordan Golubov
Keyword(s):  
Leaf Area ◽  
Environmental Conditions ◽  
High Salinity ◽  
Stomatal Density ◽  
Salinity Gradient ◽  
Abiotic Factors ◽  
Tree Height ◽  
Plant Size ◽  
Leaf Length ◽  
Low Salinity

In community ecology, the knowledge of abiotic factors, that determine intraspecific variability in ecophysiological and functional traits, is important for addressing major questions, such as plant community assembly and ecosystem functioning. Mangroves have several mechanisms of resistance to salinity and most species exhibit some xeromorphic features in order to conserve water. Leaf area and stomatal density play an important role in maintaining water balance, and gas exchange is regulated by their aperture and density, two traits that vary intraspecifically in response to environmental conditions, such as water stress and salinity. In this study, we evaluated the effects of salinity on stomatal density, leaf area and plant size in R. mangle and we tested for associations among the three variables, across three sites along a natural salinity gradient in the Xel-Há Park, Quintana Roo, Mexico. We hypothesized that high salinity sites would produce smaller plants, with smaller leaves, and fewer stomata. Three sampling sites with different environmental conditions were chosen and salinities were monitored monthly. A total of 542 plants were tagged and tree heights and diameters were measured for each individual within each of the three sampling sites. Three leaves from 20 trees from each site were measured to determine leaf area. Stomatal densities were determined in each leaf using nail polish casts, examining ten 1 mm squares per leaf under an optical microscope. A principal component analysis was used to assess association between tree height, leaf area, and stomatal density for each plot. The salinity gradient was reflected in plant size, producing smaller plants at the higher salinity site. The largest leaves were found at the low salinity site (51.2 ± 24.99 cm2). Leaf length was not correlated to plant size (LL vs. tree height: r= 0.02, P= 0.8205; LL vs. trunk diameter: r= 0.03, P= 0.7336), so we concluded that leaf length is an environmentally plastic trait of red mangroves that may vary as a function of environmental conditions, such as hydric stress caused by elevated salinity. The larger leaves from the low salinity site had lower densities of stomata (65.0 stomata.mm2 SD= 12.3), and increasing salinities did not decrease stomatal density (intermediate salinity site: 73.4 stomata.mm2 SD= 13.5; high salinity site: 74.8 stomata.mm2 SD= 17.3). Our results confirm that stomatal density is inversely related to leaf area (r= -0.29, P < 0.001), especially leaf width (r= -0.31, P < 0.001), and that salinity may increase stomatal density by causing reduction of leaf size.

scholarly journals Leaf Structural Traits Vary With Plant Size in Even-Aged Stands of Sapindus mukorossi

2021 ◽  
Vol 12 ◽  
Author(s):  
Yunni Chang ◽  
Chaobin Xu ◽  
Hong Yang ◽  
Junxin Zhou ◽  
Weiping Hua ◽  
...  
Keyword(s):  
Leaf Area ◽  
Negative Correlation ◽  
Oil Quality ◽  
Leaf Tissue ◽  
Tree Height ◽  
Plant Size ◽  
Leaf Length ◽  
Fruit Yield ◽  
Research Attention ◽  
Structural Traits

Sapindus mukorossi Gaertn., an important oleaginous woody plant, has garnered increasing research attention owing to its potential as a source of renewable energy (biodiesel). Leaf structural traits are closely related to plant size, and they affect the fruit yield and oil quality. However, plant size factors that predominantly contribute to leaf structural traits remain unknown. Therefore, the purpose of this study was to understand the associations between leaf structural traits and plant size factors in even-aged stands of S. mukorossi. Results showed that leaf length (LL) and leaf area (LA) markedly increased with the increasing diameter at breast height (DBH) and tree height (TH), although other leaf structural traits did not show noticeable changes. Difference in slopes also indicated that the degree of effect of plant size factors on leaf structural traits was in the order of TH &gt; DBH. Leaf structural traits showed no systematic variation with crown width (CW). LA was significantly positively correlated with LL, leaf width (LW), LL/LW, and leaf thickness (LT) and was significantly but negatively correlated with leaf tissue density (LTD) and leaf dry mass content (LDMC). Specific leaf area showed a significantly negative correlation with LT, LDMC, and LTD. LTD showed a significantly positive correlation with LDMC, but a negative correlation with LT. The results were critical to understand the variability of leaf structural traits with plant size, can provide a theoretical foundation for further study in the relationship between leaf structural traits and fruit yield, and regulate leaf traits through artificial management measures to promote plant growth and fruit yield.

scholarly journals Large seasonal and spatial variation in nano- and microphytoplankton diversity along a Baltic Sea—North Sea salinity gradient

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Malin Olofsson ◽  
James G. Hagan ◽  
Bengt Karlson ◽  
Lars Gamfeldt
Keyword(s):  
Community Structure ◽  
Temporal Variation ◽  
High Salinity ◽  
Salinity Gradient ◽  
Seasonal Succession ◽  
Phytoplankton Diversity ◽  
Cell Abundance ◽  
Low Salinity ◽  
Spatio Temporal ◽  
The Impact

Abstract Aquatic phytoplankton experience large fluctuations in environmental conditions during seasonal succession and across salinity gradients, but the impact of this variation on their diversity is poorly understood. We examined spatio-temporal variation in nano- and microphytoplankton (> 2 µm) community structure using almost two decades of light-microscope based monitoring data. The dataset encompasses 19 stations that span a salinity gradient from 2.8 to 35 along the Swedish coastline. Spatially, both regional and local phytoplankton diversity increased with broad-scale salinity variation. Diatoms dominated at high salinity and the proportion of cyanobacteria increased with decreasing salinity. Temporally, cell abundance peaked in winter-spring at high salinity but in summer at low salinity. This was likely due to large filamentous cyanobacteria blooms that occur in summer in low salinity areas, but which are absent in higher salinities. In contrast, phytoplankton local diversity peaked in spring at low salinity but in fall and winter at high salinity. Whilst differences in seasonal variation in cell abundance were reasonably well-explained by variation in salinity and nutrient availability, variation in local-scale phytoplankton diversity was poorly predicted by environmental variables. Overall, we provide insights into the causes of spatio-temporal variation in coastal phytoplankton community structure while also identifying knowledge gaps.

Salinity tolerances of three succulent halophytes (Tecticornia spp.) differentially distributed along a salinity gradient

2016 ◽  
Vol 43 (8) ◽  
pp. 739 ◽  
Author(s):  
Louis Moir-Barnetson ◽  
Erik J. Veneklaas ◽  
Timothy D. Colmer
Keyword(s):  
Growth Rates ◽  
Shoot Growth ◽  
High Salinity ◽  
Salt Lake ◽  
Salinity Gradient ◽  
Saline Soils ◽  
Low Salinity ◽  
Substrate Limitation ◽  
Extreme Salinity ◽  
Osmotic Potentials

We evaluated tolerances to salinity (10–2000 mM NaCl) in three halophytic succulent Tecticornia species that are differentially distributed along a salinity gradient at an ephemeral salt lake. The three species showed similar relative shoot and root growth rates at 10–1200 mM NaCl; at 2000 mM NaCl, T. indica subsp. bidens (Nees) K.A.Sheph and P.G.Wilson died, but T. medusa (K.A.Sheph and S.J.van Leeuwen) and T. auriculata (P.G.Wilson) K.A.Sheph and P.G.Wilson survived but showed highly diminished growth rates and were at incipient water stress. The mechanisms of salinity tolerance did not differ among the three species and involved the osmotic adjustment of succulent shoot tissues by the accumulation of Na+, Cl– and the compatible solute glycinebetaine, and the maintenance of high net K+ to Na+ selectivity to the shoot. Growth at extreme salinity was presumably limited by the capacity for vacuolar Na+ and Cl– uptake to provide sufficiently low tissue osmotic potentials for turgor-driven growth. Tissue sugar concentrations were not reduced at high salinity, suggesting that declines in growth would not have been caused by inadequate photosynthesis and substrate limitation compared with plants at low salinity. Equable salt tolerance among the three species up to 1200 mM NaCl means that other factors are likely to contribute to species composition at sites with salinities below this level. The lower NaCl tolerance threshold for survival in T. indica suggests that this species would be competitively inferior to T. medusa and T. auriculata in extremely saline soils.

scholarly journals Rule-based analysis of throughfall kinetic energy to evaluate biotic and abiotic factor thresholds to mitigate erosive power

2016 ◽  
Vol 40 (3) ◽  
pp. 431-449 ◽  
Author(s):  
Philipp Goebes ◽  
Karsten Schmidt ◽  
Werner Härdtle ◽  
Steffen Seitz ◽  
Felix Stumpf ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Kinetic Energy ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Abiotic Factors ◽  
Tree Height ◽  
Abiotic Factor ◽  
Area Index ◽  
Biotic And Abiotic Factors ◽  
Optimal Set

Below vegetation, throughfall kinetic energy (TKE) is an important factor to express the potential of rainfall to detach soil particles and thus for predicting soil erosion rates. TKE is affected by many biotic (e.g. tree height, leaf area index) and abiotic (e.g. throughfall amount) factors because of changes in rain drop size and velocity. However, studies modelling TKE with a high number of those factors are lacking. This study presents a new approach to model TKE. We used 20 biotic and abiotic factors to evaluate thresholds of those factors that can mitigate TKE and thus decrease soil erosion. Using these thresholds, an optimal set of biotic and abiotic factors was identified to minimize TKE. The model approach combined recursive feature elimination, random forest (RF) variable importance and classification and regression trees (CARTs). TKE was determined using 1405 splash cup measurements during five rainfall events in a subtropical Chinese tree plantation with five-year-old trees in 2013. Our results showed that leaf area, tree height, leaf area index and crown area are the most prominent vegetation traits to model TKE. To reduce TKE, the optimal set of biotic and abiotic factors was a leaf area lower than 6700 mm2, a tree height lower than 290 cm combined with a crown base height lower than 60 cm, a leaf area index smaller than 1, more than 47 branches per tree and using single tree species neighbourhoods. Rainfall characteristics, such as amount and duration, further classified high or low TKE. These findings are important for the establishment of forest plantations that aim to minimize soil erosion in young succession stages using TKE modelling.

Growth and Photosynthetic Responses of Spinach to Salinity: Implications of K+ Nutrition for Salt Tolerance

1990 ◽  
Vol 17 (5) ◽  
pp. 563 ◽  
Author(s):  
WS Chow ◽  
MC Ball ◽  
JM Anderson
Keyword(s):  
Quantum Yield ◽  
Leaf Area ◽  
Shoot Growth ◽  
High Salinity ◽  
Photosynthetic Capacity ◽  
Cytochrome F ◽  
Shoot Biomass ◽  
Unit Leaf Area ◽  
Low Salinity ◽  
Unit Leaf

To compare the effects of K+ under high and low salinity, spinach plants (Spinacia oleracea) were grown in nutrient solutions containing either 50 mM NaCl (low salinity) or 250 mM NaCl (high salinity), with a diurnal regime of 10 h light (~300 μmol photons m-2 s-1, 23°C) and 14 h dark (15°C). At each level of salinity, the nutrient KCl concentration was 0.01, 0.1, 1 or 10 mM. The plant and shoot biomass was greater at low salinity than high salinity and increased with the logarithmic increase in nominal K+ concentrations supplied to the roots. Plant and shoot growth were related to the K+ uptake into the leaves, with leaves having a higher K+ content under low salinity than high salinity. Variation of the K+ content in the leaves, induced by the combinations of nutrient KCl concentrations with high or low salinity, were accompanied by changes in the photosynthetic capacity at light- and CO2-saturation per unit leaf area; there was a greater decrease in photosynthetic capacity with decreasing K+ supply to the roots under high salinity than under low salinity. The photosynthetic capacity was in turn highly correlated with the contents of cytochrome f and ATP synthase per unit leaf area. Under conditions of high salinity and low K+ supply, a reduction in the quantum yield of oxygen evolution also occurred, due to malfunction of photosystem II and, apparently, an increased proportion of light absorbed by non-photosynthetic tissue. The decreases in photosynthetic capacity and quantum yield partly account for the lower plant and shoot biomass at high salinity and low nutrient KCl concentrations. Our results suggest strongly that there are higher K+ requirements for shoot growth under high than low salinity conditions, and that high concentrations of Na+ in the leaves may help to maintain turgor, but cannot substitute for adequate K+ levels in the leaves, presumably because K+ is specifically required for protein synthesis. Increasing the K+ supply at the roots can ameliorate reductions in plant and shoot biomass imposed by an increase in salinity.

Reproduction of Viola mirabilis in relation to light and nutrient availability

1995 ◽  
Vol 73 (12) ◽  
pp. 1917-1924 ◽  
Author(s):  
Tanja Mattila ◽  
Veikko Salonen
Keyword(s):  
Leaf Area ◽  
Nutrient Availability ◽  
Environmental Conditions ◽  
Plant Size ◽  
Fruit Production ◽  
Mating Strategies ◽  
Forest Understory ◽  
Mixed Mating ◽  
Mode Of Reproduction ◽  
Chasmogamous Flowers

Mixed mating strategies in plants, such as chasmogamy and cleistogamy, may have evolved to optimize reproductive response to local, often variable, environmental conditions. A 2-year field experiment was conducted to examine the effects of light and nutrient availability on growth and chasmogamous and cleistogamous flower and fruit production in Viola mirabilis, a perennial forest understory herb. Using a factorial design, we examined whether the mode of reproduction or reproductive output of V. mirabilis would be influenced by a repeated fertilizer application and (or) gradual shading with artificial plants. In this population of V. mirabilis, the predominant mode of reproduction during both study years was chasmogamy. In the 2nd year of study, the number of both chasmogamous and cleistogamous flowers per plant decreased with decreasing light intensity, while the increased nutrient supply had no effect on flower or fruit production or plant growth. In addition, the proportion of cleistogamous flowers was smaller for shaded plants. However, the change in the proportion of cleistogamous or chasmogamous flowers from 1993 to 1994 was not affected by shading or fertilization. The production of cleistogamous flowers correlated positively with final total leaf area during both study years, while no correlation was found between the number of chasmogamous flowers and leaf area. In most studies, chasmogamy has been found to be dependent on plant size and favourable environmental conditions, whereas cleistogamy is generally considered to be relatively independent of these factors. However, our results suggest that only plants reaching a large size were capable of producing cleistogamous flowers in addition to chasmogamous flowers produced earlier in the season. Also, it seems that the general assumption of cleistogamic reproduction as a more advantageous mode of reproduction in poor light conditions compared with chasmogamy does not apply to V. mirabilis. Key words: chasmogamy, cleistogamy, light, nutrients, reproductive success, Viola mirabilis.

Variability Studies in Morphometric Traits on Quercus leucotrichophora A. Camus Natural Populations in Himachal Pradesh

2017 ◽  
Vol 40 (2) ◽  
pp. 121-125
Author(s):  
Sangeeta Devi ◽  
◽  
H.P. Sankhyan ◽  
Sanjeev Thakur ◽  
◽  
...  
Keyword(s):  
Leaf Area ◽  
Significant Variation ◽  
Large Diameter ◽  
Tree Height ◽  
Himachal Pradesh ◽  
Leaf Length ◽  
Leaf Width ◽  
Diameter Class ◽  
Morphometric Traits ◽  
Quercus Leucotrichophora

Variability studies on Quercus leucotrichophora A. Camus Populations (Banoak) in Himachal Pradesh was carried out during 2014-16 for selection of best phenotypes. In order to select best sites for improved genetic gain and quality production of Quercus leucotrichophora, eight sites and three D.B.H. classes from Himachal Pradesh were evaluated on the basis of morphometric traits. The study revealed significant variation among different sites for traits viz., tree height, clean bole height, crown width, leaf area, leaf length, leaf width. Whereas, among the different diameter classes all the traits showed significant variation except number of primary branches, leaf area, leaf width. Over all site S8 (Salooni-Chamba) was found to be superior followed by Site S6 (Manikaran-Kullu) for all traits. Diameter class D3 ( > 60 cm) excelled in morphometric traits. Study concluded that superiority of S8 (Salooni) and S6 (Manikaran) populations from large diameter class D3 ( > 60 cm dbh) for obtaining seed /propagules for further testing and obtaining best results.

Carbon-Isotope, Diatom, and Pollen Evidence for Late Holocene Salinity Change in a Brackish Marsh in the San Francisco Estuary

2001 ◽  
Vol 55 (1) ◽  
pp. 66-76 ◽  
Author(s):  
Roger Byrne ◽  
B. Lynn Ingram ◽  
Scott Starratt ◽  
Frances Malamud-Roam ◽  
Joshua N. Collins ◽  
...  
Keyword(s):  
San Francisco ◽  
High Salinity ◽  
Carbon Isotopic Composition ◽  
Brackish Marsh ◽  
San Francisco Estuary ◽  
Freshwater Inflow ◽  
Water Diversion ◽  
Freshwater Flow ◽  
Low Salinity ◽  
Carbon Isotopic

AbstractAnalysis of diatoms, pollen, and the carbon-isotopic composition of a sediment core from a brackish marsh in the northern part of the San Francisco Estuary has provided a paleosalinity record that covers the past 3000 yr. Changes in marsh composition and diatom frequencies are assumed to represent variations in freshwater inflow to the estuary. Three periods of relatively high salinity (low freshwater inflow) are indicated, 3000 to 2500 cal yr B.P., 1700 to 730 cal yr B.P., and ca. A.D. 1930 to the present. The most recent period of high salinity is primarily due to upstream storage and water diversion within the Sacramento–San Joaquin watershed, although drought may also have been a factor. The two earlier high-salinity periods are likely the result of reduced precipitation. Low salinity (high freshwater flow) is indicated for the period 750 cal yr B.P. to A.D. 1930.

scholarly journals Photosynthesis of Blueberry Leaves as Affected by Septoria Leaf Spot and Abiotic Leaf Damage

Plant Disease ◽  
2004 ◽  
Vol 88 (4) ◽  
pp. 397-401 ◽  
Author(s):  
I. Roloff ◽  
H. Scherm ◽  
M. W. van Iersel
Keyword(s):  
Leaf Area ◽  
Disease Severity ◽  
Leaf Spot ◽  
Abiotic Factors ◽  
Lesion Size ◽  
Leaf Conductance ◽  
Yield Potential ◽  
Leaf Spots ◽  
Virtual Lesion ◽  
Septoria Leaf Spot

Leaf spots caused by fungal pathogens or abiotic factors can be prevalent on southern blueberries after harvest during the summer and fall, yet little is known about how they affect physiological processes that determine yield potential for the following year. In this study, we measured CO2 assimilation and leaf conductance on field-grown blueberry plants affected by Septoria leaf spot (caused by Septoria albopunctata) or by edema-like abiotic leaf blotching. Net assimilation rate (NAR) on healthy leaves varied between 6.9 and 12.4 μmol m-2 s-1 across cultivars and measurement dates. Infection by S. albopunctata had a significant negative effect on photosynthesis, with NAR decreasing exponentially as disease severity increased (R2 ≥0.726, P < 0.0001). NAR was reduced by approximately one-half at 20% disease severity, and values approached zero for leaves with >50% necrotic leaf area. There was a positive, linear correlation between NAR and leaf conductance (R2 ≥ 0.622, P < 0.0001), suggesting that the disease may have reduced photosynthesis via decreased CO2 diffusion into affected leaves. Estimates of virtual lesion size associated with infection by S. albopunctata ranged from 2.8 to 3.1, indicating that the leaf area in which photosynthesis was impaired was about three times as large as the area covered by necrosis. For leaves afflicted by edema-like damage, there also was a significant negative relationship between NAR and affected leaf area, but the scatter about the regression was more pronounced than in the NAR-disease severity relationships for S. albopunctata (R2 = 0.548, P < 0.0001). No significant correlation was observed between leaf conductance and affected area on these leaves (P = 0.145), and the virtual lesion size associated with abiotic damage was significantly smaller than that caused by S. albopunctata. Adequate carbohydrate supply during the fall is critical for optimal flower bud set in blueberry; therefore, these results document the potential for marked yield losses due to biotic and abiotic leaf spots.

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