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  • 1
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    Online Resource
    Plant Age Has a Minor Effect on Non-Destructive Leaf Area Calculations in Moso Bamboo (Phyllostachys edulis)
    MDPI AG ; 2021
    In:  Symmetry Vol. 13, No. 3 ( 2021-02-25), p. 369-
    Details
    In: Symmetry, MDPI AG, Vol. 13, No. 3 ( 2021-02-25), p. 369-
    Abstract: Leaf area is among the most important leaf functional traits, and it determines leaf temperature and alters light harvesting. The calculation of individual leaf area is the basis of calculating the leaf area index (i.e., the total leaf area per unit ground area) that is directly associated with the ability of plants to intercept light for photosynthesis. It is valuable to provide a fast and reliable approach to measuring leaf area. Here, we examined the validity and calculation accuracy of the Montgomery equation (ME), which describes the area of a leaf as a product of leaf length, width and a specific coefficient referred to as the Montgomery parameter, MP. Using ME, we calculated leaf areas of different age groups of bamboo culms. For most broad-leaved plants, leaf area is proportional to the product of leaf length and width, and MP falls within a range of 1/2 to π/4, depending on leaf shape. However, it is unknown whether there is an intra-specific variation in MP resulting from age structure and whether such a variation can significantly reduce the predictability of ME in calculating leaf area. This is relevant as a population of perennial plants usually composes of different age groups. We used Moso bamboos as model as this species is of ecological and economic importance in southern China, and pure stands can cover six to seven plant age groups. We used five age groups of moso bamboo and sampled 260–380 leaves for each group to test whether ME holds true for each group and all groups combined, whether there are significant differences in MP among different age groups, and whether the differences in MP can lead to large prediction errors for leaf area. We observed that for each age group and all groups combined, there were significant proportional relationships between leaf area and the product of leaf length and width. There were small but significant differences in MP among the five age groups (MP values ranged from 0.6738 to 0.7116 for individual plant ages; MP = 0.6936 for all age groups combined), which can be accounted for by the minor intergroup variation of leaf shape (reflected by the leaf width/length ratio). For all age classes, MP estimated for the pooled data resulted in 〈 4% mean absolute percentage error, indicating that the effect of variation in MP among different age groups was small. We conclude that ME can serve as a useful tool for accurate calculations of leaf area in moso bamboo independent of culm age, which is valuable for estimation of leaf area index as well as evaluating the productivity and carbon sequestration capacity of bamboo forests.
    Type of Medium: Online Resource
    ISSN: 2073-8994
    URL: Article
    DOI: 10.3390/sym13030369
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2518382-5
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  • 2
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    Alternaria Black Spot (Alternaria brassicae) Infection Severity on Cruciferous Oilseed Crops
    MDPI AG ; 2021
    In:  Applied Sciences Vol. 11, No. 18 ( 2021-09-13), p. 8507-
    Details
    In: Applied Sciences, MDPI AG, Vol. 11, No. 18 ( 2021-09-13), p. 8507-
    Abstract: The increase in the cultivation area of cruciferous oilseed crops and the use of short crop rotation has resulted in the enhanced spread of several major pests in Northern latitudes. There is currently limited information about incidence and severity of Alternaria black spot disease (Alternaria brassicae) on the main oilseed crop, spring oilseed rape (Brassica napus), in the Northern Baltics. Thus, spring oilseed rape and five alternative cruciferous oilseed crops were selected and their resistance to black spot disease was evaluated in field conditions during two growing seasons. We hypothesized that spring oilseed rape is more susceptible to Alternaria black spot disease than other alternative cruciferous oilseed crops. Both growing seasons were warmer and drier compared to the long-term average, and were thus suitable for A. brassicae development and assessments. In both years, incidence of Alternaria black spot infection was recorded on all cruciferous species, yet the disease development differed considerably among the crops. During both growing seasons, black mustard (B. nigra) plants were the most infected. Based on our observations during warm growing seasons we conclude that alternative oilseed crops such as Sinapis alba, Eruca sativa and Raphanus sativus are more resistant to the Alternaria black spot infection than the traditional oilseed crops and thus, possess a great potential to grow with limited chemical disease control in Northern Baltic conditions.
    Type of Medium: Online Resource
    ISSN: 2076-3417
    URL: Article
    DOI: 10.3390/app11188507
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2704225-X
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  • 3
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    Can Leaf Shape be Represented by the Ratio of Leaf Width to Length? Evidence from Nine Species of Magnolia and Michelia (Magnoliaceae)
    MDPI AG ; 2020
    In:  Forests Vol. 12, No. 1 ( 2020-12-30), p. 41-
    Details
    In: Forests, MDPI AG, Vol. 12, No. 1 ( 2020-12-30), p. 41-
    Abstract: Leaf shape is closely related to economics of leaf support and leaf functions, including light interception, water use, and CO2 uptake, so correct quantification of leaf shape is helpful for studies of leaf structure/function relationships. There are some extant indices for quantifying leaf shape, including the leaf width/length ratio (W/L), leaf shape fractal dimension (FD), leaf dissection index, leaf roundness index, standardized bilateral symmetrical index, etc. W/L ratio is the simplest to calculate, and recent studies have shown the importance of the W/L ratio in explaining the scaling exponent of leaf dry mass vs. leaf surface area and that of leaf surface area vs. leaf length. Nevertheless, whether the W/L ratio could reflect sufficient geometrical information of leaf shape has been not tested. The FD might be the most accurate measure for the complexity of leaf shape because it can characterize the extent of the self-similarity and other planar geometrical features of leaf shape. However, it is unknown how strongly different indices of leaf shape complexity correlate with each other, especially whether W/L ratio and FD are highly correlated. In this study, the leaves of nine Magnoliaceae species ( 〉 140 leaves for each species) were chosen for the study. We calculated the FD value for each leaf using the box-counting approach, and measured leaf fresh mass, surface area, perimeter, length, and width. We found that FD is significantly correlated to the W/L ratio and leaf length. However, the correlation between FD and the W/L ratio was far stronger than that between FD and leaf length for each of the nine species. There were no strong correlations between FD and other leaf characteristics, including leaf area, ratio of leaf perimeter to area, fresh mass, ratio of leaf fresh mass to area, and leaf roundness index. Given the strong correlation between FD and W/L, we suggest that the simpler index, W/L ratio, can provide sufficient information of leaf shape for similarly-shaped leaves. Future studies are needed to characterize the relationships among FD and W/L in leaves with strongly varying shape, e.g., in highly dissected leaves.
    Type of Medium: Online Resource
    ISSN: 1999-4907
    URL: Article
    DOI: 10.3390/f12010041
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2527081-3
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  • 4
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    Ozone and Wounding Stresses Differently Alter the Temporal Variation in Formylated Phloroglucinols in Eucalyptus globulus Leaves
    MDPI AG ; 2019
    In:  Metabolites Vol. 9, No. 3 ( 2019-03-06), p. 46-
    Details
    In: Metabolites, MDPI AG, Vol. 9, No. 3 ( 2019-03-06), p. 46-
    Abstract: Formylated phloroglucinol compounds (FPCs) are a class of plant specialized metabolite present in the Myrtaceae family, especially in the genus Eucalyptus. FPCs are widely investigated due to their herbivore deterrence properties and various bioactivities of pharmaceutical relevance. Despite the increasing number of studies elucidating new FPCs structures and bioactivity, little is known about the role of those compounds in planta, and the effects of environmental stresses on FPC concentration. Ozone (O3) and wounding are key stress factors regularly confronted by plants. In this study, we investigated how O3, wounding, and their combination affected individual and total FPC foliar concentration of the economically important species Eucalyptus globulus. Six individual FPCs, including five macrocarpals and one sideroxylonal, showed different response patterns to the single and combined stresses. Total macrocarpals only increased under single O3 treatment, whereas total sideroxylonals only increased in response to wounding treatment, suggesting different physiological roles played by the two groups of FPCs predominantly existing in E. globulus foliage. Total FPCs increased significantly under individual wounding and O3 treatments but not under the combined treatment. A principal component analysis indicated that all different treatments had unique FPC fingerprints. Total phenolic contents increased in all O3 and wounding treatments, and a marginally positive correlation was found between total FPCs and total phenolic contents. We suggest that, depending on the concentration and composition, FPCs play multiple physiological roles in planta, including serving as antioxidants to scavenge the reactive oxygen species brought about by O3 and wounding stresses.
    Type of Medium: Online Resource
    ISSN: 2218-1989
    URL: Article
    DOI: 10.3390/metabo9030046
    Language: English
    Publisher: MDPI AG
    Publication Date: 2019
    detail.hit.zdb_id: 2662251-8
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  • 5
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    Leaf Bilateral Symmetry and the Scaling of the Perimeter vs. the Surface Area in 15 Vine Species
    MDPI AG ; 2020
    In:  Forests Vol. 11, No. 2 ( 2020-02-23), p. 246-
    Details
    In: Forests, MDPI AG, Vol. 11, No. 2 ( 2020-02-23), p. 246-
    Abstract: The leaves of vines exhibit a high degree of variability in shape, from simple oval to highly dissected palmatifid leaves. However, little is known about the extent of leaf bilateral symmetry in vines, how leaf perimeter scales with leaf surface area, and how this relationship depends on leaf shape. We studied 15 species of vines and calculated (i) the areal ratio (AR) of both sides of the lamina per leaf, (ii) the standardized symmetry index (SI) to estimate the deviation from leaf bilateral symmetry, and (iii) the dissection index (DI) to measure leaf-shape complexity. In addition, we examined whether there is a scaling relationship between leaf perimeter and area for each species. A total of 14 out of 15 species had no significant differences in average ln(AR), and mean ln(AR) approximated zero, indicating that the areas of the two lamina sides tended to be equal. Nevertheless, SI values among the 15 species had significant differences. A statistically strong scaling relationship between leaf perimeter and area was observed for each species, and the scaling exponents of 12 out of 15 species fell in the range of 0.49−0.55. These data show that vines tend to generate a similar number of left- and right-skewed leaves, which might contribute to optimizing light interception. Weaker scaling relationships between leaf perimeter and area were associated with a greater DI and a greater variation in DI. Thus, DI provides a useful measure of the degree of the complexity of leaf outline.
    Type of Medium: Online Resource
    ISSN: 1999-4907
    URL: Article
    DOI: 10.3390/f11020246
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2527081-3
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  • 6
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    High Temporal Variability in Late Blight Pathogen Diversity, Virulence, and Fungicide Resistance in Potato Breeding Fields: Results from a Long-Term Monitoring Study
    MDPI AG ; 2022
    In:  Plants Vol. 11, No. 18 ( 2022-09-16), p. 2426-
    Details
    In: Plants, MDPI AG, Vol. 11, No. 18 ( 2022-09-16), p. 2426-
    Abstract: Long-term site-specific studies describing changes in the phenotypic variability of Phytophthora infestans populations allow quantitative predictions of pathogen spread and possible outbreaks of epidemics, and provide key input for regional resistance breeding programs. Late blight samples were collected from potato (Solanum tuberosum) breeding fields in Estonia during a twelve-year study period between 2001 and 2014. In total, 207 isolates were assessed for mating type and 235 isolates for metalaxyl resistance and 251 isolates for virulence factors. The frequency of mating types strongly fluctuated across the years, whereas the later period of 2010–2014 was dominated by the A2 mating. Despite fluctuations, both mating types were recorded in the same fields in most years, indicating sustained sexual reproduction of P. infestans with oospore production. Metalaxyl-resistant and intermediately resistant strains dominated in the first years of study, but with the progression of the study, metalaxyl-sensitive isolates became dominant, reaching up to 88%. Racial diversity, characterized by normalized Shannon diversity index decreased in time, varying from 1.00 in 2003 to 0.43 in 2013. The frequency of several virulence factors changed in a time-dependent manner, with R2 increasing and R6, R8, and R9 decreasing in time. Potato cultivar resistance background did not influence the frequency of P. infestans mating type, response to metalaxyl, and racial diversity. However, the diversity index decreased in time among isolates collected from resistant and susceptible cultivars, and remained at a high level in moderately resistant cultivars. These data demonstrate major time-dependent changes in racial diversity, fungicide resistance, and virulence factors in P. infestans, consistent with alterations in the control strategies and popularity of potato cultivars with different resistance.
    Type of Medium: Online Resource
    ISSN: 2223-7747
    URL: Article
    DOI: 10.3390/plants11182426
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2704341-1
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  • 7
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    Comparison of Two Simplified Versions of the Gielis Equation for Describing the Shape of Bamboo Leaves
    MDPI AG ; 2022
    In:  Plants Vol. 11, No. 22 ( 2022-11-11), p. 3058-
    Details
    In: Plants, MDPI AG, Vol. 11, No. 22 ( 2022-11-11), p. 3058-
    Abstract: Bamboo is an important component in subtropical and tropical forest communities. The plant has characteristic long lanceolate leaves with parallel venation. Prior studies have shown that the leaf shapes of this plant group can be well described by a simplified version (referred to as SGE-1) of the Gielis equation, a polar coordinate equation extended from the superellipse equation. SGE-1 with only two model parameters is less complex than the original Gielis equation with six parameters. Previous studies have seldom tested whether other simplified versions of the Gielis equation are superior to SGE-1 in fitting empirical leaf shape data. In the present study, we compared a three-parameter Gielis equation (referred to as SGE-2) with the two-parameter SGE-1 using the leaf boundary coordinate data of six bamboo species within the same genus that have representative long lanceolate leaves, with 〉 300 leaves for each species. We sampled 2000 data points at approximately equidistant locations on the boundary of each leaf, and estimated the parameters for the two models. The root–mean–square error (RMSE) between the observed and predicted radii from the polar point to data points on the boundary of each leaf was used as a measure of the model goodness of fit, and the mean percent error between the RMSEs from fitting SGE-1 and SGE-2 was used to examine whether the introduction of an additional parameter in SGE-1 remarkably improves the model’s fitting. We found that the RMSE value of SGE-2 was always smaller than that of SGE-1. The mean percent errors among the two models ranged from 7.5% to 20% across the six species. These results indicate that SGE-2 is superior to SGE-1 and should be used in fitting leaf shapes. We argue that the results of the current study can be potentially extended to other lanceolate leaf shapes.
    Type of Medium: Online Resource
    ISSN: 2223-7747
    URL: Article
    DOI: 10.3390/plants11223058
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2704341-1
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  • 8
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    Combined Acute Ozone and Water Stress Alters the Quantitative Relationships between O3 Uptake, Photosynthetic Characteristics and Volatile Emissions in Brassica nigra
    MDPI AG ; 2021
    In:  Molecules Vol. 26, No. 11 ( 2021-05-23), p. 3114-
    Details
    In: Molecules, MDPI AG, Vol. 26, No. 11 ( 2021-05-23), p. 3114-
    Abstract: Ozone (O3) entry into plant leaves depends on atmospheric O3 concentration, exposure time and openness of stomata. O3 negatively impacts photosynthesis rate (A) and might induce the release of reactive volatile organic compounds (VOCs) that can quench O3, and thereby partly ameliorate O3 stress. Water stress reduces stomatal conductance (gs) and O3 uptake and can affect VOC release and O3 quenching by VOC, but the interactive effects of O3 exposure and water stress, as possibly mediated by VOC, are poorly understood. Well-watered (WW) and water-stressed (WS) Brassica nigra plants were exposed to 250 and 550 ppb O3 for 1 h, and O3 uptake rates, photosynthetic characteristics and VOC emissions were measured through 22 h recovery. The highest O3 uptake was observed in WW plants exposed to 550 ppb O3 with the greatest reduction and poorest recovery of gs and A, and elicitation of lipoxygenase (LOX) pathway volatiles 10 min–1.5 h after exposure indicating cellular damage. Ozone uptake was similar in 250 ppb WW and 550 ppb WS plants and, in both treatments, O3-dependent reduction in photosynthetic characteristics was moderate and fully reversible, and VOC emissions were little affected. Water stress alone did not affect the total amount and composition of VOC emissions. The results indicate that drought ameliorated O3 stress by reducing O3 uptake through stomatal closure and the two stresses operated in an antagonistic manner in B. nigra.
    Type of Medium: Online Resource
    ISSN: 1420-3049
    URL: Article
    DOI: 10.3390/molecules26113114
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2008644-1
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  • 9
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    Role of Stomatal Conductance in Modifying the Dose Response of Stress-Volatile Emissions in Methyl Jasmonate Treated Leaves of Cucumber (Cucumis Sativa)
    MDPI AG ; 2020
    In:  International Journal of Molecular Sciences Vol. 21, No. 3 ( 2020-02-04), p. 1018-
    Details
    In: International Journal of Molecular Sciences, MDPI AG, Vol. 21, No. 3 ( 2020-02-04), p. 1018-
    Abstract: Treatment by volatile plant hormone methyl jasmonate (MeJA) leads to release of methanol and volatiles of lipoxygenase pathway (LOX volatiles) in a dose-dependent manner, but how the dose dependence is affected by stomatal openness is poorly known. We studied the rapid (0–60 min after treatment) response of stomatal conductance (Gs), net assimilation rate (A), and LOX and methanol emissions to varying MeJA concentrations (0.2–50 mM) in cucumber (Cucumis sativus) leaves with partly open stomata and in leaves with reduced Gs due to drought and darkness. Exposure to MeJA led to initial opening of stomata due to an osmotic shock, followed by MeJA concentration-dependent reduction in Gs, whereas A initially decreased, followed by recovery for lower MeJA concentrations and time-dependent decline for higher MeJA concentrations. Methanol and LOX emissions were elicited in a MeJA concentration-dependent manner, whereas the peak methanol emissions (15–20 min after MeJA application) preceded LOX emissions (20–60 min after application). Furthermore, peak methanol emissions occurred earlier in treatments with higher MeJA concentration, while the opposite was observed for LOX emissions. This difference reflected the circumstance where the rise of methanol release partly coincided with MeJA-dependent stomatal opening, while stronger stomatal closure at higher MeJA concentrations progressively delayed peak LOX emissions. We further observed that drought-dependent reduction in Gs ameliorated MeJA effects on foliage physiological characteristics, underscoring that MeJA primarily penetrates through the stomata. However, despite reduced Gs, dark pretreatment amplified stress-volatile release upon MeJA treatment, suggesting that increased leaf oxidative status due to sudden illumination can potentiate the MeJA response. Taken together, these results collectively demonstrate that the MeJA dose response of volatile emission is controlled by stomata that alter MeJA uptake and volatile release kinetics and by leaf oxidative status in a complex manner.
    Type of Medium: Online Resource
    ISSN: 1422-0067
    URL: Article
    DOI: 10.3390/ijms21031018
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2019364-6
    SSG: 12
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  • 10
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    Highly Diverse Phytophthora infestans Populations Infecting Potato Crops in Pskov Region, North-West Russia
    MDPI AG ; 2022
    In:  Journal of Fungi Vol. 8, No. 5 ( 2022-04-30), p. 472-
    Details
    In: Journal of Fungi, MDPI AG, Vol. 8, No. 5 ( 2022-04-30), p. 472-
    Abstract: There is limited understanding of the genetic variability in Phytophthora infestans in the major potato cultivation region of north-western Russia, where potato is grown primarily by small households with limited chemical treatment of late blight. In this study, the mating type, sensitivity to metalaxyl, and genotype and population genetic diversity (based on 12 simple sequence repeat (SSR) markers) of 238 isolates of P. infestans from the Pskov region during the years 2010–2013 were characterized. The aim was to examine the population structure, phenotypic and genotypic diversity, and the prevalent reproductive mode of P. infestans, as well as the influence of the location, time, and agricultural management practices on the pathogen population. The frequency of the A2 mating was stable over the four seasons and ranged from 33 to 48% of the sampled population. Both mating types occurred simultaneously in 90% of studied fields, suggesting the presence of sexual reproduction and oospore production in P. infestans in the Pskov region. Metalaxyl-sensitive isolates prevailed in all four years (72%), however, significantly fewer sensitive isolates were found in samples from large-scale conventional fields. A total of 50 alleles were detected in the 141 P. infestans isolates analyzed for genetic diversity. Amongst the 83 SSR multilocus genotypes (MLGs) detected, 65% were unique and the number of MLGs varied between locations from 3 to 20. These results, together with the high genotypic diversity observed in all the locations and the lack of significance of linkage disequilibrium, suggest that sexual recombination is likely responsible for the unique MLGs and the high genetic diversity found in the Pskov region population, resembling those of north-eastern European populations.
    Type of Medium: Online Resource
    ISSN: 2309-608X
    URL: Article
    DOI: 10.3390/jof8050472
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2784229-0
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