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opencc-zeroFeb 2024View details →

Effects of leaf silicon on drought performance of tropical tree seedlings

Elevated leaf silicon (Si) concentrations improve drought resistance in cultivated plants, suggesting Si might also improve the drought performance of wild species. Tropical tree species, for instance, take up substantial amounts of Si, and leaf Si varies markedly at local- and regional-scales, suggesting consequences for seedling drought resistance. Yet, whether elevated leaf Si improves seedling drought performance in tropical forests is unknown. To manipulate leaf Si concentrations, seedlings of seven tropical tree species were grown in Si-rich and -poor soil, before exposing them to drought in the forest understory. Survival, growth, and wilting were monitored. Elevated leaf Si did not improve drought survival and growth in any of the species. In one species, drought survival was reduced in seedlings previously grown in Si-rich soil, contrary to our expectations. Our results suggest that elevated leaf Si does not improve the drought resistance of wild tropical tree species. Elevated leaf Si may even reduce drought performance, suggesting differences in soil conditions influencing leaf Si may contribute to soil-related variation of tropical seedling performance. Furthermore, our results are at odds with most studies on cultivated species and show that alleviative effects of Si in crops cannot be generalized to wild plants in natural systems.

opencc-zeroMar 2024View details →

Global leaf sulphur stoichiometry and the relationships with nitrogen and phosphorus: phylogeny, growth form and environmental controls

Sulphur (S) is an essential bioelement with vital roles in serving regulatory and catalytic functions, and tightly coupled with N and P in plants. However, globally stoichiometric patterns of leaf S and its relationships to leaf N and P are less well studied. We compiled 31,939 records of leaf-based data for 2,600 plant species across 6,652 sites worldwide. All plant species were divided into different phylogenetic taxa and growth forms. Standard major axis analysis was employed to fit the bivariate element relationships. A phylogenetic linear mixed effect model and a multiple regression model were used to partition the variations of bioelements into phylogeny and environments, and then to estimate the importance of environmental variables. Global geometric mean leaf S, N and P concentrations were 1.44, 15.70 and 1.27 mg g-1, with significant differences among plant groups. Leaf S-N-P positively correlated to each other, ignoring plant groups. The scaling exponents of LN-LS, LP-LS and LN-LP were 0.64, 0.76 and 0.79 for all species, but differed among plant groups. Both phylogeny and environments regulated the bioelements. The variability, rather than mean temperature controlled the bioelements. Phylogeny explained more for the concentrations of all the three bioelements than environments, of which S was the one most affected by phylogenetic taxa.

Forest inventory, leaf area index, and leaf functional traits of various land cover classes in Kulen, Cambodia

<ol><li>Sub-title 1: Forest inventory of evergreen forest, regrowth forest, and evergreen forest in Kulen, Cambodia. (File name: Forest_Inventory_Pub.txt)  </li><li>Sub-title 2: Species leaf area, chlorophyll a and b and leaf dry matter content of 30 species collected from evergreen forests, regrowth forests, and cashew plantation in Kulen, Cambodia. (File name: Leaf_Trait_Species_Pub.txt)</li><li>Sub-title 3: Canopy and total leaf area index from evergreen forests, regrowth forests, and cashew plantation in Kulen, Cambodia. (File name: LAI_Pub.txt )</li></ol>

opencc-zeroMar 2024View details →

Leaf fluctuating asymmetry is not a reliable indicator of stress

Stress experienced during development in organisms with bilateral structures could result in developmental instability, which is expressed as subtle non-directional deviations from perfect symmetry, known as fluctuating asymmetry (FA). As such, FA has been proposed, and extensively used, as a trait indicating stress for many organisms with bilateral structures and many types of stress. However, while this concept may apply to animals, the evidence for plants' main vegetative structures, i.e., leaves, remains equivocal, and a comprehensive synthesis on this topic is still missing. We designed observational field and controlled greenhouse studies, combining different growth and leaf forms across multiple stress gradients, comprising 21 species and 80 populations. We measured FA as the difference between the left and right area of the leaf, an approach that accommodates diverse leaf forms. We used high-precision, blind, single-person measurements and tested for other forms of symmetry and the effect of leaf size. We further complemented our study with a systematic literature review of FA in plant leaves, compiling 51 studies comprising 72 species, 23 stress types, and 131 unique entries (species × stress type). We consistently found no effect of stress on leaf FA in any of the studied species in both our field and experimental gradients. In the systematic literature review, only 39% of the unique entries showed the expected increase in FA with stress, 53% showed no effect, 9% showed an opposite trend of a decrease in FA with stress, and 1% showed an unimodal relationship. Importantly, only 40% of all entries fulfilled the crucial step of controlling for a high-precision measurement, and of these 49% reported the expected increase of FA with stress. Both the results of our observational and experimental approaches and the systematic literature review failed to support a clear relationship between stress and FA in plant leaves. These results clearly show that FA in plant leaves cannot be used as a reliable trait indicating stress during development.

opencc-by-4.0Mar 2023View details →

Classification and identification of pinecones mulching on blueberry cultivation based on crop leaf characteristics and hyperspectral data

Supplementary Figure S1: Spectra preprocessing before and after.; Table S1: The evaluation results of the classification model of leaf growth and physiology.; Table S2: The evaluation results of the classification model of VIs.; Table S3: The evaluation results of the classification model of VNIR.; Table S4: The evaluation results of the classification model of SWIR.

16S rDNA sequencing data for characterizing the endosymbionts of leaf curl plum aphid ( Brachycaudus helichrysi) clones

Asexual lineages often exhibit broad distributions and can thrive in extreme habitats compared to their sexual counterparts. Several hypotheses can be proposed to explain this pattern. Asexual lineages could be versatile genotypes with wide environmental tolerance, enabling their dispersal and persistence across large geographic areas. Alternatively, asexual genotypes could be ecological specialists that thrive in specific environments and outcompete relatives colonizing distantly related areas with similar conditions in the process. Several aphid species feature widespread obligate asexual lineages, commonly known as "superclones". Yet it is often unknown whether these clones are widespead ecological generalists or successful specialists. To explore these hypotheses, we examined climatic niche differentiation among six globally distributed obligate asexual lineages of the cosmopolitan aphid pest, Brachycaudus helichrysi. To insure that we were investigating the aphid genotype niche and not a by-product of their association with endosymbionts mediating thermal tolerance, we first verified that clones hosted similar endosymbiont communities. Subsequently, we conducted multivariate analyses on clone occurrence data on a worldwide scale. Our results revealed that despite their global distribution, B. helichrysi superclones occupy different climatic niches. This study represents the first evidence that aphid superclones distribution can be mediated by distinctive ranges of climatic tolerance.

Figs 8–12 in REVIEW OF LEAF BEETLES OF THE SUBGENUS HYPERICIA BEDEL, 1899 (COLEOPTERA: CHRYSOMELIDAE: CHRYSOLINA) FROM EAST ASIA

Figs 8–12. Aedeagus in dorsal and lateral view. 8 – Chrysolina difficilis Motschulsky

Figs 6–7 in REVIEW OF LEAF BEETLES OF THE SUBGENUS HYPERICIA BEDEL, 1899 (COLEOPTERA: CHRYSOMELIDAE: CHRYSOLINA) FROM EAST ASIA

Figs 6–7. Habitus in dorsal view. 6 – Chrysolina changbaishana sp. n., holotype, male (S

Figs 17–20 in REVIEW OF LEAF BEETLES OF THE SUBGENUS HYPERICIA BEDEL, 1899 (COLEOPTERA: CHRYSOMELIDAE: CHRYSOLINA) FROM EAST ASIA

Figs 17–20. Habitus in dorsal view and labels of the types. Chrysolina gracilis Bechyně:

Figs 21–22 in REVIEW OF LEAF BEETLES OF THE SUBGENUS HYPERICIA BEDEL, 1899 (COLEOPTERA: CHRYSOMELIDAE: CHRYSOLINA) FROM EAST ASIA

Figs 21–22. Aedeagus in dorsal and lateral view. 21 – Chrysolina gracilis Bechyně,

Figs 4–5 in REVIEW OF LEAF BEETLES OF THE SUBGENUS HYPERICIA BEDEL, 1899 (COLEOPTERA: CHRYSOMELIDAE: CHRYSOLINA) FROM EAST ASIA

Figs 4–5. Aedeagus in dorsal and lateral view. 4 – Chrysolina geminata Paykull (Achit

Below-ground root nutrient-acquisition strategies are more sensitive to long-term grazing than above-ground leaf traits across a soil nutrient gradient

Understanding how plant nutrient acquisition strategies respond to grazing at the community level is critical to understanding ecosystem structure and functioning in grasslands. However, few studies have simultaneously compared the difference in aboveground (leaf) and belowground (root) nutrient-acquisition strategies in response to long-term grazing, especially at the regional scale. Here, we measured a set of leaf and fine-root traits that correspond to the fast-slow economic spectrum at the community level in 10 experimental sites from paired grazed and ungrazed grasslands across a soil nutrient gradient covering three major types of grasslands in northern China. We found that patterns of variations of leaf and fine-root traits were consistent with both a leaf and root economic spectrum at the community level for both grazed and non-grazed plots. Grazing had a minor effect on community-level leaf nutrient-acquisition strategies but strongly influenced community-level root nutrient-acquisition strategies. Specifically, root nutrient-acquisition strategies were shifted to more exploitative resource use in grazed communities. Moreover, soil nutrients contributed to the changes in both leaf and root nutrient-acquisition strategies, which tended towards a more resource-acquisition strategy with increasing soil nutrient levels. Grazing significantly interacted with soil nutrients to affect root nutrient-acquisition strategies, and grazing contributed more to root nutrient-acquisition strategies than soil nutrients. Our results demonstrated completely inconsistent responses of community-level above- and below-ground resource acquisition strategies to long-term grazing, and below-ground acquisition strategies were more sensitive to long-term grazing. Our findings also suggest that high-intensity anthropogenic activities such as grazing may strongly modify below-ground resource acquisition strategies.

Negative allometry of leaf xylem conduit diameter and double-wall thickness: implications for implosion safety

Xylem conduits have lignified walls to resist crushing pressures. The thicker the double-wall (T) relative to its diameter (D), the greater the implosion safety. Having safer conduits may incur higher costs and reduced flow, while having less resistant xylem may lead to catastrophic collapse under drought. Although recent studies have shown that conduit implosion commonly occurs in leaves, little is known about how leaf xylem scales T versus D to trade off safety, flow efficiency, mechanical support, and cost. We measured T and D in > 7,000 conduits of 122 species to investigate how T versus D scaling varies across clades, habitats, growth forms, leaf and vein sizes. As conduits become wider, their double-cell walls become proportionally thinner, resulting in a negative allometry between T and D. That is, narrower conduits, which are usually subjected to more negative pressures, are proportionally safer than wider ones. Higher implosion safety (i.e higher T/D ratios) was found in asterids, arid habitats, shrubs, small leaves, and minor veins. Despite the strong allometry, implosion safety does not clearly trade off with other measured leaf functions, suggesting that implosion safety at whole-leaf level cannot be easily predicted solely by individual conduits' anatomy.

opencc-by-4.0Mar 2024View details →

Exploring Beneficial Properties of Haskap Berry Leaf Compounds for Gut Health Enhancement

Data and the publication to which they are related

Vertical stratification of leaf physical traits exerts bottom-up pressures on insect herbivory in a sugar maple temperate forest

Do vertical gradients in temperate forest structure insect herbivore communities? We tested the hypothesis that the increase in light intensity from understory to forest canopy level drives differences in leaf physical traits and budburst phenology that impact insect herbivores and thus play a role in structuring both herbivore communities and the leaf damages they cause. Twelve sugar maple (Acer saccharum) sites were monitored in southern Quebec, examining insect herbivore patterns from understory to the shaded and sun canopy over the summers of 2020, 2021, and 2022. Additionally, we recorded leaf physical traits, temperature, humidity, and sun exposure. Our findings revealed that leaf thickness increased along the vertical gradient in 2021, making leaves less favorable to herbivores in the canopy level. Accordingly, we recorded a consistent decrease in insect herbivory damage rates from the understory to the shaded canopy and sun canopy in 2020 and 2021, driven by leaf cutters, skeletonizers, stipplers, and leaf miners. These results support our hypothesis that variation in plant physical traits due to sun exposure contributes to the vertical stratification of insect damage. In 2022, the gradient of insect herbivore abundance corroborated the observed damage trends from the previous years. Moreover, we calculated an average annual herbivory rate of 9.1% of the leaf surface in our study site, suggesting limited evidence supporting a significant contribution of background herbivory to the decline of sugar maple forests. Overall, our study highlights the importance of vertical gradients in structuring insect herbivore communities and emphasizes the role of leaf traits in mediating these interactions.

opencc-by-4.0Nov 2022View details →

Figure 4. Regression between senescence leaf N in Foliar resorption of nitrogen and phosphorus in Alcea apterocarpa (Malvaceae) in different habitats types

Figure 4. Regression between senescence leaf N/P ratio and RE and RP of A. apterocarpa.

opencc-by-4.0Nov 2022View details →

Figure 3. Regression between green leaf N in Foliar resorption of nitrogen and phosphorus in Alcea apterocarpa (Malvaceae) in different habitats types

Figure 3. Regression between green leaf N/P ratio and RE and RP of A. apterocarpa.

Drought shortens subtropical understory growing season by advancing leaf senescence

Subtropical forests, recognized for their intricate vertical canopy stratification, exhibit high resistance to extreme drought. However, the response of leaf phenology to drought in the species-rich understory remains poorly understood. In this study, we constructed a digital camera system, amassing over 360,000 images through a 70% throughfall exclusion experiment, to explore the drought response of understory leaf phenology. The results revealed a significant advancement in understory leaf senescence phenology under drought, with 11.75 and 15.76 days for the start and end of the leaf-falling event, respectively. Pre-season temperature primarily regulated leaf development phenology, whereas soil water dominated the variability in leaf senescence phenology. Under drought conditions, temperature sensitivities for the end of leaf emergence decreased from -13.72 days ℃-1 to -11.06 days ℃-1, with insignificance observed for the start of leaf emergence. Consequently, drought treatment shortened both the length of the growing season (15.69 days) and the peak-growth season (9.80 days) for understory plants. Moreover, this study identified diverse responses among intra- and inter-species to drought, particularly during the leaf development phase. These findings underscore the pivotal role of water availability in shaping understory phenology patterns, especially in subtropical forests.

opencc-by-4.0Dec 2018View details →

Quercus michauxii (Fagaceae) - leaf

Image of Quercus michauxii (Fagaceae) - leaf