Differences In Leaf Morphology Research Articles

Morphological and Physiological Characteristics Influencing CO2 Assimilation Rate and Growth in Different Half-Sib Families of Quercus acuta and Q. glauca

Climate change alters vegetation patterns, pushing subtropical forests further north. These forests play a crucial role for carbon neutrality efforts due to their significant CO2 assimilation potential. This study investigated CO2 assimilation rate along with growth, morphological, and physiological traits in 23 half-sib families of Quercus acuta and 26 half-sib families of Q. glauca, two prominent East Asian evergreen broadleaf species. Q. acuta exhibited significantly higher growth rates, with diameter at breast height (DBH) and aboveground biomass exceeding those for Q. glauca by 12.1% and 69.9%, respectively (p < 0.001). Leaf traits, including leaf mass pear area (LMA), leaf nitrogen, and chlorophyll content, were also greater in Q. acuta, showing 24.5%, 45.8%, and 15.6% higher values (p < 0.001). While photosynthetic traits were similar, Q. acuta exhibited a 12.7% higher intrinsic water-use efficiency (iWUE) (p < 0.01). Among half-sib families, marginal differences were observed in growth traits (p < 0.1), and significant differences in leaf morphology and physiological traits (p < 0.05) were observed. A positive correlation was found between growth and physiological traits associated with the CO2 assimilation rate in Q. acuta, but not in Q. glauca. These findings highlight the potential of Q. acuta and Q. glauca for supporting future carbon neutrality efforts and provide traits supporting carbon uptake, valuable for selecting tree species with enhanced carbon sequestration potential.

Research on Corn Leaf and Stalk Recognition and Ranging Technology Based on LiDAR and Camera Fusion.

Corn, as one of the three major grain crops in China, plays a crucial role in ensuring national food security through its yield and quality. With the advancement of agricultural intelligence, agricultural robot technology has gained significant attention. High-precision navigation is the basis for realizing various operations of agricultural robots in corn fields and is closely related to the quality of operations. Corn leaf and stalk recognition and ranging are the prerequisites for achieving high-precision navigation and have attracted much attention. This paper proposes a corn leaf and stalk recognition and ranging algorithm based on multi-sensor fusion. First, YOLOv8 is used to identify corn leaves and stalks. Considering the large differences in leaf morphology and the large changes in field illumination that lead to discontinuous identification, an equidistant expansion polygon algorithm is proposed to post-process the leaves, thereby increasing the average recognition completeness of the leaves to 86.4%. Secondly, after eliminating redundant point clouds, the IMU data are used to calculate the confidence of the LiDAR and depth camera ranging point clouds, and point cloud fusion is performed based on this to achieve high-precision ranging of corn leaves. The average ranging error is 2.9 cm, which is lower than the measurement error of a single sensor. Finally, the stalk point cloud is processed and clustered using the FILL-DBSCAN algorithm to identify and measure the distance of the same corn stalk. The algorithm combines recognition accuracy and ranging accuracy to meet the needs of robot navigation or phenotypic measurement in corn fields, ensuring the stable and efficient operation of the robot in the corn field.

Leaf Anatomy Structure of Codiaeum variegatum (L.) Rumph. ex A. Juss Cultivars

Codiaeum variegatum (L.) Rumph. ex a. Juss is a common ornamental plant with a high variation of leaves shape and colour. This study aimed to analyze the leaves’ anatomy and the phenetic relationship between eight cultivars of C. variegatum which were defined by the differences in leaf morphology. The paraffin method prepared the transversal section of leaves, and anatomical characters were converted into binary data to calculate the similarity coefficient which was analyzed by Numerical Taxonomy System (NTSYS) 2.1 version. Leaves of eight cultivars of C. variegatum are varied in the anatomical structure of the primary vein and lamina. The eight cultivars of C. variegatum were clustered into four. The variations were found in 19 primary vein and lamina anatomy characteristics and the similarity coefficient is up to 0.59 between all cultivars. It can be concluded that the combination of leaf anatomical structures and midrib anatomical characters have notable taxonomic implications for future research.

Genome Doubling of Northern Spicebush, Lindera benzoin L.

Lindera benzoin is a dioecious understory shrub native to eastern North America. Northern spicebush is a beautiful shrub with a natural round shrub shape, golden-yellow fall foliage, attractive bright red drupes, and precocious yellow flowers in early spring; however, its market value as an ornamental value has been overlooked. To improve the ornamental values of this under-cultivated nursery crop, breeding for a better compact form, larger leaves, enlarged flower clusters and fruit, and increased stress tolerances could all be beneficial. Polyploidy manipulation is a valuable method to improve such traits for many ornamental plants. This study established the genome doubling method by oryzalin-infused solid agar treatment on young northern spicebush seedlings. The seedlings of two wild populations in North Carolina were collected and used. A total of 288 seedlings were treated with solid agar containing 150 µM oryzalin for 24, 72, and 120 h. The results were sporadic in their survival ratios and tetraploid conversion ratios between different treatments; however, a total of 16 tetraploid L. benzoin plants were produced in this study. The 24-h treatment showed the optimal result, with 7.1% of total treated seedlings or 15.2% of surviving seedlings converted into tetraploids. Tetraploid plants had visible differences in leaf morphology, a statistically significant enlarged stomata size, and reduced stomatal density compared to diploid plants. This research provides ploidy manipulation information for all future breeding processes of L. benzoin and related species.

Differences in Leaf Morphology and Related Gene Expression between Diploid and Tetraploid Birch (Betula pendula).

Plant polyploidization changes its leaf morphology and leaf development patterns. Understanding changes in leaf morphology and development patterns is a prerequisite and key to studying leaf development in polyploid plants. In this study, we quantified and analyzed the differences in leaf morphology, leaf growth polarity, and leaf size between diploid and tetraploid birches (Betula pendula subsp. pendula), and preliminarily investigated genes involved in leaf growth and development in birch. The results showed significant changes in leaf morphology in tetraploid birches, especially the basal part of the leaf. In addition, the proximal growth rate of tetraploid leaves was altered. The changed proximal growth rate did not affect the growth polarity pattern of tetraploid leaves. The leaf area of tetraploid was significantly larger than that of diploid birch. The difference in leaf size was mainly due to differences in their growth rates in the middle and late stages of leaf development. Increased cell expansion capacity was the major reason for the enormous leaves of tetraploid birch; however, cell proliferation did not contribute to the larger tetraploid leaf. The gene expression of ATHB12 was associated with cell size and leaf area, and may be a critical gene affecting the leaf size in diploid and tetraploid birches. The results will provide valuable insights into plant polyploid leaf development and a theoretical basis for later investigations into the molecular mechanisms underlying the gigantism of tetraploid birch leaves.

Aneuploidy promotes intraspecific diversification of the endemic East Asian herb Lycoris aurea complex.

Polyploidy has received considerable interest in the past, but aneuploidy and partial rearrangements may also influence genomic divergence. In this study, we reported a comprehensive cytogeographic, morphological and genetic analysis of Lycoris aurea complex throughout its range and attempted to explore the association between aneuploidy and species diversification. The karyotypes of this complex presented aneuploidy variations mainly divided into four cytotypes: I (2n = 10m + 2T), II (2n = 8m + 6T), III (2n = 7m + 8T), and IV (2n = 6m + 10T). Cytotype distributions were highly structured geographically. Two main cytotypes, II and IV, are geographically allopatric. The populations with cytotype II are mainly distributed in central China and the southern islands of Japan. Cytotypes IV is disjunctly distributed in southwestern and southeastern China. The cytotypes with fewer chromosome numbers tend to occur at high latitudes. For analyzing the phylogeographic pattern and genetic structure of this complex, we sequenced four chloroplast DNA fragments (4,748 bp in total) of 241 individuals from 42 populations. Extremely high diversity of cpDNA haplotypes was found, with genetic diversity index (Hd) being 0.932 and 98.61% of the genetic variation occurring among populations, indicating that this complex has undergone strong intraspecific differentiation. The cytotype II had the highest haplotype diversity (Hd = 0.885), while cytotype IV harbored the highest nucleotide diversity (π = 4.09 × 10–3). We detected significant leaf morphological differences not only between cytotype II and IV but also between west lineage and east lineage within cytotype IV. These results illustrated that aneuploidy contributed to extensive morphological and genetic differentiation in L. aurea complex. It was suggested that L. aurea complex should comprise multiple independent evolutionary lineages, and accurate species delimitation needs to be established further in an integrative taxonomic approach.

Comparative Analysis and Phylogenetic Study of the Chloroplast Genome Sequences of Two Korean Endemic Primula Varieties

Primula comprises many species of horticultural value. In Korea, six species grow in the wild. Yamazaki classified the variety Primula modesta var. fauriei into P. modesta var. hannasanensis and P. modesta var. koreana based on the differences in leaf morphology. We compared the chloroplast genome sequences of the two Korean endemic Primula varieties and found that both had the typical quadripartite structure of angiosperms. The chloroplast genome size of P. modesta var. hannasanensis is 154,772 bp, including an 85,238 bp large single-copy region and a 17,790 bp small single-copy region, whereas that of P. modesta var. koreana is 154,667 bp, including an 85,152 bp large single-copy region and a 17,771 bp small single-copy region. The inverted repeat region is 25,872 bp in both varieties. We predicted 129 genes—84 protein-coding genes, 8 rRNAs, and 37 tRNAs. We identified 536 single-nucleotide polymorphisms and 501 indels between the varieties. Phylogenetic analysis revealed that the two varieties formed a sister group in the clade P. knuthiana–P. stenocalyx. This study will contribute to phylogenetic, taxonomic, and evolutionary studies of the genus Primula; it will also contribute to the analysis of the genetic diversity of the two varieties, and to the development of identification markers.

Multispecies forest plantations outyield monocultures across a broad range of conditions.

Multispecies tree planting has long been applied in forestry and landscape restoration in the hope of providing better timber production and ecosystem services; however, a systematic assessment of its effectiveness is lacking. We compiled a global dataset of matched single-species and multispecies plantations to evaluate the impact of multispecies planting on stand growth. Average tree height, diameter at breast height, and aboveground biomass were 5.4, 6.8, and 25.5% higher, respectively, in multispecies stands compared with single-species stands. These positive effects were mainly the result of interspecific complementarity and were modulated by differences in leaf morphology and leaf life span, stand age, planting density, and temperature. Our results have implications for designing afforestation and reforestation strategies and bridging experimental studies of biodiversity-ecosystem functioning relationships with real-world practices.

Morphological description and DNA barcoding study of Paramignya trimera collected in Khanh Hoa, Vietnam

Paramignya trimera is a valuable traditional medicinal plant, typically distributing in Khanh Hoa, Vietnam. In recent years, P. trimera has been exploited to treat liver diseases such as hepatitis, cirrhosis and liver cancers. The recorded during the investigation, in Khanh Hoa currently appears a number of species with similar phenotypes known collectively as P. trimera and appeared some morphology with differences in leaf morphology and thorns. Therefore, this study was carried out for identification, breeding and propagation conservation.This study has been described, characterized morphological characteristics and analyzed DNA barcodes based on ITS, matK and rbcL gene markers. About the morphology, P. trimera is distinguished from other species of the genus Paramignya with the following characteristics: elongated, single leaf, leaf-shaped lobe end, leaf veins shaped like a feather. Petiole with big, pointed and straight spines. Corolla 3, 6 stamens, upper election, with three sepals and two ovule leaves, the seed has a seed coat. The analysis of DNA barcodes shows that the results combination of the analysis of the three regions of ITS, matK and rbcL can be used to determine the genetic relationship between five samples of P. trimera. The nucleotide sequence lengths of the samples for the three regions of the ITS, matK and rbcL genes are 850 bp, 850 bp and 500 bp, respectively. On the basis of phenotypic tree analysis, the samples (X1, X2, X3, X4, X5) have the same evolutionary origin in ITS, matK and rbcL. Base on to identified the five morphological forms of P. trimera distributed in Khanh Hoa as the same species and expanded the distribution area as well as in-depth research on P. trimera morphologies in Khanh Hoa, Vietnam.

Host ancestry and morphology differentially influence bacterial and fungal community structure of Rhododendron leaves, roots, and soil

Rhododendron are popular ornamental plants that are well-known for forming mycorrhizal associations with ericoid fungi, but little is known about how host traits influence their microbiome more broadly. This study investigated leaf, root, rhizosphere soil, and bulk soil bacterial and fungal community structure for 12 Rhododendron species, representing four taxonomic clades with different leaf habits. Samples were collected when ephemeral hair roots colonized by ericoid mycorrhizae were absent, and microbial community structure was compared to leaf and root morphology for the same plants. Root morphology and the fungal communities of roots and rhizosphere soil were primarily structured by host ancestry. Leaf bacterial and fungal communities were even more distinct across clades than for roots or rhizosphere, and microbial communities of leaves and bulk soil were similarly structured by clade-wise differences in leaf morphology, suggesting a role for Rhododendron leaf litter in belowground microbial community structure. This work sheds new light on host traits influencing microbial community structure of ericaceous plants, showing a strong influence of ancestry, but also that different host traits drive bacterial and fungal communities across different plant compartments, suggesting future work on factors that drive similarity among close relatives in the non-ericoid microbes associating with Rhododendron.

Growth and photosynthetic traits differ between shoots originated from axillary buds or from adventitious buds in Populus balsamifera L. cuttings.

Bud development influences shoot branching and the plasticity and adaptability of plants. To explore the differences of post-embryonic development of different types of buds, shoots originated from adventitious buds and axillary buds of cuttings in two populations of balsam poplar (Populus balsamifera L.) were investigated for differences in leaf morphology, photosynthetic and growth characteristics, and the effects of a carbonic anhydrase (CA) inhibitor on CA activity, photosynthesis and mesophyll conductance (gm ). The results showed that axillary buds produced ovate first few leaves and longer shoots while adventitious buds produced lanceolate first few leaves with higher specific leaf area (SLA). There were no significant differences in leaf area-based photosynthetic rate (An ), maximum carboxylation rate (Vcmax ), and maximum electron transport rate (Jmax ) between shoots originated from the two bud types. Based on the principal component analysis, shoots of adventitious bud origin grouped on daytime respiration and SLA, while cuttings from axillary buds clustered toward the opposite direction of quantum yield and light saturation point. Shoots originated from different types of buds had different growth rates and biomass, but the direction of the differences varied with the population of the mother tree. The two populations differed in An , gm , and relationships between CA, An , and gm . There were differences in post-embryonic growth traits of shoots from axillary buds and those from adventitious buds, which may be an adaptive strategy for regeneration under different light conditions.

Variation in Leaf Morphology of Sago Trees (Metroxylon sagu) in South Borneo Province, Indonesia.

Natural populations of sago (Metroxylon sagu) in Indonesia show morphological variations in its organs, particularly the leaves. The existing variations resulted in sago type names provided by the locals. The sago plant types include Mahang, Buntal, Salak, Madang and Gandut. Sago leaves are economically important in Indonesia, mainly because they provide a potentially profitable and environment-friendly source of house roofing materials. Determining leaf variation among sago plants would provide information for a better way of choosing which among the current accessions/varieties of sago has the best leaf quality and production. Leaf variations in sago were recorded in shape, size, and color. The aim of this study are a) to compare differences in leaf morphology among sago types obtained from different geographic areas, and b) to determine whether these different sago types correspond to certain sago plant grouping. The qualitative and quantitative analysis showed variations in leaf characteristics of sago trees. Additionally, this study shows that based on leaf variations, the sago of South Borneo Province can be separated into two groups. The first group is Mahang and Gandut, which have long rachis, leaflets and leaves, and largest leaf area. The second group composed of Buntal, Salak and Madang accessions, which have short rachis and leaves, and smallest leaf area. Other results showed that there were characters that contributed significantly to the diversity of sago plants in the study area including spines, white stripe or banding on the rachis and petiole length. In line with our results, Mahang and Gandut accessions are the best accessions to be cultivated in the area, because they have wider leaves which support higher rates of photosynthesis. Further study should be conducted on phylogenetic using DNA sequencing to confirm divisions of the two sago groups. 

Leaf morphological characteristics of section Quercus based on geometric morphometric analysis.

We conducted leaf geometric morphometric analysis (GMMs) for five Quercus species (Section Quercus) of Fagaceae. In total, 887 leaves chosen from 182 individuals of 20 natural popu-lations were marked with GMMs. Leaf morphological characteristics of these samples were digitized to visualize leaf morphological differences. Generalized Procrustes analysis could effectively exclude the influence of leaf position and size on leaf shape. Results of principal component analysis at tree-level showed that the leaf morphology of Q. dentata was different with Q. aliena and Q. serrata. Canonical variates analysis at tree-level showed that leaf morphology of Q. aliena could be accurately distinguished from the other four species in leaf symmetric components. The results of multivariate analysis of asymmetrical components in leaves showed no distinction among the five species. The analysis at leaf-level showed that the two groups with a higher degree of discrimination were Q. aliena vs. Q. dentata (99.5% vs. 100%) and Q. dentata vs. Q. serrata (99.0% vs. 100%), which could be accurately distinguished by leaf shape. The two groups with a slightly lower degree of discrimination were Q. fabri vs. Q. serrata (90.5% vs. 86.8%) and Q. dentata vs. Quercus mongolica (85.1% vs. 82.9%). Our results provided new insights for the leaf shape identification among species with frequent hybridization and introgression.

<strong>New names in <em>Pittosporum</em>, extant and fossil (<em>Pittosporaceae</em>)</strong>

The nomenclature of some homonyms of Pittosporum is resolved. Fossil Pittosporum elegans (Ettingshausen) W.R.B. Oliver, being an illegitimate later homonym of extant Pittosporum elegans Raoul, is re-named R. ettingshausenii nom. nov. Pittosporum pulchrum Gagnepain (extant) is replaced by a new name P. gagnepainii nom. nov., because of the earlier homonym, Pittosporum pulchrum Saporta (fossil). Pittosporum pulchrum Gagnepain and Pittosporum pulchrum Saporta are both lectotypified for the first time. Fossil Pittosporum beringianum is excluded from Pittosporum on the basis of differences in leaf morphology and segregated in the distinct fossil-genus Xenopanax gen. nov.

Deciduous and evergreen oaks show contrasting adaptive responses in leaf mass per area across environments.

Increases in leaf mass per area (LMA) are commonly observed in response to environmental stresses and are achieved through increases in leaf thickness and/or leaf density. Here, we investigated how the two underlying components of LMA differ in relation to species native climates and phylogeny, across deciduous and evergreen species. Using a phylogenetic approach, we quantified anatomical, compositional and climatic variables from 40 deciduous and 45 evergreen Quercus species from across the Northern Hemisphere growing in a common garden. Deciduous species from shorter growing seasons tended to have leaves with lower LMA and leaf thickness than those from longer growing seasons, while the opposite pattern was found for evergreens. For both habits, LMA and thickness increased in arid environments. However, this shift was associated with increased leaf density in evergreens but reduced density in deciduous species. Deciduous and evergreen oaks showed fundamental leaf morphological differences that revealed a diverse adaptive response. While LMA in deciduous species may have diversified in tight coordination with thickness mainly modulated by aridity, diversification of LMA within evergreens appears to be dependent on the infrageneric group, with diversification in leaf thickness modulated by both aridity and cold, while diversification in leaf density is only modulated by aridity.

High Heterogeneity in Canopy Temperature Among Co‐occurring Tree Species in a Temperate Forest

AbstractTrees regulate canopy temperature (Tc) via transpiration to maintain an optimal temperature range. In diverse forests such as those of the eastern United States, the sensitivity of Tc to changing environmental conditions may differ across species, reflecting wide variability in hydraulic traits. However, these links are not well understood in mature forests, where Tc data have historically been difficult to obtain. Recent advancement of thermal imaging cameras (TICs) enables Tc measurement of previously inaccessible tall trees. By leveraging TIC and sap flux measurements, we investigated how co‐occurring trees (Quercus alba, Q. falcata, and Pinus virginiana) change their Tc and vapor pressure deficit near the canopy surface (VPDc) in response to changing air temperature (Ta) and atmospheric VPD (VPDa). We found a weaker cooling effect for the species that most strongly regulates stomatal function during dry conditions (isohydric; P. virginiana). Specifically, the pine had higher Tc (up to 1.3°C) and VPDc (up to 0.3 kPa) in the afternoon and smaller sensitivity of both ∆T (=Tc − Ta) and ∆VPD (=VPDc − VPDa) to changing conditions. Furthermore, significant differences in Tc and VPDc between sunlit and shaded portions of a canopy implied a non‐evaporative effect on Tc regulation. Specifically, Tc was more homogeneous within the pine canopy, reflecting differences in leaf morphology that allow higher canopy transmittance of solar radiation. The variability of Tc among species (up to 1.3°C) was comparable to the previously reported differences in surface temperature across land cover types (1°C to 2°C), implying the potential for significant impact of species composition change on local/regional surface temperature.

Biogeographic divergence in leaf traits of Sapindus mukorossi and Sapindus delavayi and its relation to climate

To explore differences in leaf morphology between Sapindus mukorossi and Sapindus delavayi, and how the environment might drive these differences, 80 germplasm samples from the Sapindus germplasm nursery in Fujian Province were selected. The study revealed a wide variation and diversity in 16 germplasm traits, both within and between species grown under the same conditions. On average, the relative contribution of intraspecific variability to total variability was more important (83%) than the relative contribution of interspecific variability (17%). PERMANOVA analysis showed differences in leaflet thickness, length, perimeter, length to width ratio, and leaf hairs or trichome density. Correlation analyses between leaf morphological traits and environmental variables indicated that leaves tended to be larger, longer, and thicker in wetter, warmer, and low-altitude conditions. Our analysis of the relationship between climate and leaf morphology revealed that S. mukorossi had a greater sensitivity to climate variation, particularly in response to mean temperatures of the coldest and warmest seasons, which led to differences in leaf traits and the distribution of the two species. These findings contribute to the understanding of leaf morphology variations in S. mukorossi and S. delavayi, and provide a basis for the collection of Sapindus germplasm resources, their cultivation and use to help address climate change.

Effects of soil moisture, needle age and leaf morphology on carbon and oxygen uptake, incorporation and allocation: a dual labeling approach with 13CO2 and H218O in foliage of a coniferous forest.

The carbon and oxygen isotopic composition of water and assimilates in plants reveals valuable information on plant responses to climatic conditions. Yet, the carbon and oxygen uptake, incorporation and allocation processes determining isotopic compositions are not fully understood. We carried out a dual-isotope labeling experiment at high humidity with 18O-enriched water (H218O) and 13C-enriched CO2 (13CO2) with attached Scots pine (Pinus sylvestris L.) branches and detached twigs of hemiparasitic mistletoes (Viscum album ssp. austriacum) in a naturally dry coniferous forest, where also a long-term irrigation takes place. After 4h of label exposure, we sampled previous- and recent-year leaves, twig phloem and twig xylem over 192h for the analysis of isotope ratios in water and assimilates. For both species, the uptake into leaf water and the incorporation of the 18O-label into leaf assimilates was not influenced by soil moisture, while the 13C-label incorporation into assimilates was significantly higher under irrigation compared with control dry conditions. Species-specific differences in leaf morphology or needle age did not affect 18O-label uptake into leaf water, but the incorporation of both tracers into assimilates was two times lower in mistletoe than in pine. The 18O-label allocation in water from pine needles to twig tissues was two times higher for phloem than for xylem under both soil moisture conditions. In contrast, the allocation of both tracers in pine assimilates were similar and not affected by soil moisture, twig tissue or needle age. Soil moisture effects on 13C-label but not on 18O-label incorporation into assimilates can be explained by the stomatal responses at high humidity, non-stomatal pathways for water and isotope exchange reactions. Our results suggest that non-photosynthetic 18O-incorporation processes may have masked prevalent photosynthetic processes. Thus, isotopic variation in leaf water could also be imprinted on assimilates when photosynthetic assimilation rates are low.

Inter-specific hybridization of Alnus rubra and Alnus rhombifolia: preliminary report of a new taxon and DNA marker resources for bioenergy feedstock production

Exploratory hybridization of red alder (Alnus rubra Bong.) and white alder (Alnus rhombifolia Nutt.) was conducted to initiate a long-term investigation into the inter-specific taxon’s potential for biomass production. Red alder selections originated in stands west of Oregon’s Cascade Mountains, while white alder came from provenances west and east of the Cascades. White alder’s heretofore unknown chromosome number was determined equal to red alder (2n = 2x = 28) and included a pair of satellite chromosomes. An experimental crossing technique was proven, establishing the species’ reproductive affinity for the first time. Hybridization was substantially more productive when red alder served as the female parent as opposed to white alder. Hybridity was confirmed using four species-specific SSR markers developed from transcriptome resources for identifying sib relationships in domesticated populations. To begin a description of the inter-specific taxon, hybrids and their open-pollinated siblings were assessed at ages four through six for morphological and phenological traits and carbon and nitrogen isotopic ratios in a field planting in western Washington, USA. Principal component analysis of quantitative leaf and internode morphologies showed that red alder and hybrid alder are relatively comparable and both are distinct from white alder. Qualitative differences in leaf morphology are more diagnostic with inter-specific hybrids often intermediate to red and white alder. Principal coordinate analysis of molecular data cleanly separated the three taxa. Plans for continued investigation of the taxon as a biomass crop species are discussed including a potential role for inter-specific hybrids in adapting red alder to the effects of climate change.

Morphological variation of fine root systems and leaves in primary and secondary tropical forests of Hainan Island, China

In older, unlogged rainforest of Hainan Island, China, leaves of saplings were larger, and fine root systems of saplings were thicker with fewer root tips than in historically logged areas. These results were consistent among 15 Angiosperm lineages, even though families differed widely in their leaf and root traits. How plant organ morphologies vary with environment is key for inferring plant functional strategies. We were interested in quantifying any changes in fine root and leaf morphology of saplings with local-scale environmental variation in tropical forest, and if any variation in organ morphologies differed with plant lineage. We measured functional traits of fine root systems and leaves of saplings from 15 families in historically logged and unlogged Chinese tropical forest, where soil fertility and texture slightly decreased with greater forest age. Root morphological traits were more conservative, while leaf morphologies were more acquisitive in primary forest than in secondary forest. From secondary to primary forests, mean root system diameter increased 0.4 mm, mean specific root length decreased 3.5 m kg−1, and mean root system branching intensity decreased by 0.3 tips cm−1. Similarly, from secondary to primary forests, average leaf area increased 7 cm2 and specific leaf area decreased 0.8 m2 kg−1. Leaf thickness and root tissue density were not different. Among the selected plant families, root and leaf morphological differences between forest types were consistent. Within lineage (i.e., intraspecific) root and leaf morphological variation showed contrasting patterns. Local-scale variation in soil phosphorus and base saturation affected intraspecific variation in root diameter and specific root length.