Leaf Form Research Articles

Phylogenetic analysis and evolution of morphological characters in the genus Jasminum L. (Oleaceae) in India

Jasminum L. (Oleaceae) consists of ∼200 species that are distributed in tropical, subtropical and temperate regions of the world. In India, this genus is represented by ca 47 species of which 16 are endemic. Based on the nuclear (internal-transcribed spacer (ITS) region of nrDNA and chloroplast markers (matK, trnL-F and trnH-psbA), phylogenetic relationships in 22 species including one variety of Jasminum in India have been assessed. Maximum likelihood and Bayesian analyses from individual markers, as well as from combined dataset, reveal that the group is monophyletic if Menodora spp. are excluded from the analyses. Our analyses recovered three strongly supported clades. Ancestral character state reconstruction of taxonomically useful characters (leaf forms, leaf arrangement and flower colour) which were used to demarcate sections within the genus reveals homoplasy. Our study suggests that after split from the last common ancestor, there have been at least four reversals to unifoliolate condition. Pinnately compound leaf form evolved at least twice and trifoliolate condition evolved one time only. Alternate leaf form evolved at least twice, once inclade 1 and once in clade 3 and all the time from ancestors having opposite leaf forms. Flower colour evolution clearly depicts that clade 1 is yellow-flowered and clades 2 and 3 have admixture of white and yellow-flowered Jasminum species. Our study suggests that yellow-flowered condition evolved from the white-flowered ancestor. The present study is first to estimate the evolutionary history of Indian Jasmines.

Mechanisms Underlying the Environmentally Induced Plasticity of Leaf Morphology.

The primary function of leaves is to provide an interface between plants and their environment for gas exchange, light exposure and thermoregulation. Leaves have, therefore a central contribution to plant fitness by allowing an efficient absorption of sunlight energy through photosynthesis to ensure an optimal growth. Their final geometry will result from a balance between the need to maximize energy uptake while minimizing the damage caused by environmental stresses. This intimate relationship between leaf and its surroundings has led to an enormous diversification in leaf forms. Leaf shape varies between species, populations, individuals or even within identical genotypes when those are subjected to different environmental conditions. For instance, the extent of leaf margin dissection has, for long, been found to inversely correlate with the mean annual temperature, such that Paleobotanists have used models based on leaf shape to predict the paleoclimate from fossil flora. Leaf growth is not only dependent on temperature but is also regulated by many other environmental factors such as light quality and intensity or ambient humidity. This raises the question of how the different signals can be integrated at the molecular level and converted into clear developmental decisions. Several recent studies have started to shed the light on the molecular mechanisms that connect the environmental sensing with organ-growth and patterning. In this review, we discuss the current knowledge on the influence of different environmental signals on leaf size and shape, their integration as well as their importance for plant adaptation.

Evolution of leaf structure and drought tolerance in species of Californian Ceanothus.

Studies across diverse species have established theory for the contribution of leaf traits to plant drought tolerance. For example, species in more arid climates tend to have smaller leaves of higher vein density, higher leaf mass per area, and more negative osmotic potential at turgor loss point (πTLP ). However, few studies have tested these associations for species within a given lineage that have diversified across an aridity gradient. We analyzed the anatomy and physiology of 10 Ceanothus (Rhamnaceae) species grown in a common garden for variation between and within "wet" and "dry" subgenera (Ceanothus and Cerastes, respectively) and analyzed a database for 35 species for leaf size and leaf mass per area (LMA). We used a phylogenetic generalized least squares approach to test hypothesized relationships among traits, and of traits with climatic aridity in the native range. We also tested for allometric relationships among anatomical traits. Leaf form, anatomy, and drought tolerance varied strongly among species within and between subgenera. Cerastes species had specialized anatomy including hypodermis and encrypted stomata that may confer superior water storage and retention. The osmotic potentials at turgor loss point (πTLP ) and full turgor (πo ) showed evolutionary correlations with the aridity index (AI) and precipitation of the 10 species' native distributions, and LMA with potential evapotranspiration for the 35 species in the larger database. We found an allometric correlation between upper and lower epidermal cell wall thicknesses, but other anatomical traits diversified independently. Leaf traits and drought tolerance evolved within and across lineages of Ceanothus consistently with climatic distributions. The πTLP has signal to indicate the evolution of drought tolerance within small clades.

Effect of brewing conditions on caffeine content in tea infusions simulating home-made cup of tea

To answer the question “How much caffeine do I have in my cup of tea?” we have developed a simple isocratic HPLC method with UV detection for determination of caffeine. The optimized method exhibits high repeatability; the retention time RSD was lower than 0.4% and RSD of the peak area was lower than 3.5%. The method was applied to five types of tea in loose leaf form differing in level of fermentation (black, pu-erh, oolong, green, and white). The brewing conditions were chosen to be as close as possible to domestic preparation of tea. In this study, we have focused on two important culinary factors: infusion time and brewing temperature. The results show that both investigated factors significantly influence the final content of caffeine in a cup of tea. Increase in caffeine content was up to 29% when the tea infusion was overextracted by 1 min. Increase was even higher (up to 66%) when boiling water was used instead of water of recommended temperature. It indicates that careful attitude to preparation of each type of tea is essential for caffeine content.

Recent Taxonomic Notes and New Distribution Localities of Podocarpus Pers. Species in the Philippines

The taxonomy of plants provides a great contribution to understanding diversity and conservation. This study provides additional taxonomic notes on Podocarpus species in the Philippines using newly collected specimens to determine new distribution localities of these species. This study recognises ten species of Podocarpus in the Philippines. Notable results of this study are: (1) the existence of variable leaf forms in P. pilgeri Foxw. correlated to the type of habitat where the species occurs; (2) variable leaf forms and sizes observed in mature and juvenile leaves of all species; (3) support of the sectional arrangement of P. palawanensis de Laub. & Silba; (4) differences between the wild and cultivated representatives of P. costalis C.Presl based on leaf characters; (5) new distributions for P. ramosii R.R.Mill, P. pilgeri, P. costalis, P. neriifolius D.Don, P. rumphii Blume and P. polystachyus R.Br.; (5) no support for the inclusion of P. neglectus Blume and P. hookeri de Laub. as new species found in the Philippines; and (6) comprehensive examination and identification of numerous herbarium specimens and recently collected material.

CIN‐TCP transcription factors: Transiting cell proliferation in plants

Leaves are the most conspicuous planar organs in plants, designed for efficient capture of sunlight and its conversion to energy that is channeled into sustaining the entire biosphere. How a few founder cells derived from the shoot apical meristem give rise to diverse leaf forms has interested naturalists and developmental biologists alike. At the heart of leaf morphogenesis lie two simple cellular processes, division and expansion, that are spatially and temporally segregated in a developing leaf. In leaves of dicot model species, cell division occurs predominantly at the base, concomitant with the expansion and differentiation of cells at the tip of the lamina that drives increase in leaf surface area. The timing of the transition from one cell fate (division) to the other (expansion) within a growing leaf lamina is a critical determinant of final leaf shape, size, complexity and flatness. The TCP proteins, unique to plant kingdom, are sequence-specific DNA-binding transcription factors that control several developmental and physiological traits. A sub-group of class II TCPs, called CINCINNATA-like TCPs (CIN-TCPs henceforth), are key regulators of the timing of the transition from division to expansion in dicot leaves. The current review highlights recent advances in our understanding of how the pattern of CIN-TCP activity is translated to the dynamic spatio-temporal control of cell-fate transition through the transactivation of cell-cycle regulators, growth-repressing microRNAs, and interactions with the chromatin remodeling machinery to modulate phytohormone responses. Unravelling how environmental inputs influence CIN-TCP-mediated growth control is a challenge for future studies. © 2018 IUBMB Life, 70(8):718-731, 2018.

MowJoe: a method for automated-high throughput\xa0dissected leaf phenotyping

BackgroundAccurate and automated phenotyping of leaf images is necessary for high throughput studies of leaf form like genome-wide association analysis and other forms of quantitative trait locus mapping. Dissected leaves (also referred to as compound) that are subdivided into individual units are an attractive system to study diversification of form. However, there are only few software tools for their automated analysis. Thus, high-throughput image processing algorithms are needed that can partition these leaves in their phenotypically relevant units and calculate morphological features based on these units.ResultsWe have developed MowJoe, an image processing algorithm that dissects a dissected leaf into leaflets, petiolule, rachis and petioles. It employs image skeletonization to convert leaves into graphs, and thereafter applies algorithms operating on graph structures. This partitioning of a leaf allows the derivation of morphological features such as leaf size, or eccentricity of leaflets. Furthermore, MowJoe automatically places landmarks onto the terminal leaflet that can be used for further leaf shape analysis. It generates specific output files that can directly be imported into downstream shape analysis tools. We applied the algorithm to two accessions of Cardamine hirsuta and show that our features are able to robustly discriminate between these accessions.ConclusionMowJoe is a tool for the semi-automated, quantitative high throughput shape analysis of dissected leaf images. It provides the statistical power for the detection of the genetic basis of quantitative morphological variations.

Functional diversity research of forest communities in the Xiaowutai Mountain National Nature Reserve, Hebei

Plant functional traits are the plant physiological characteristics which can response to the changes of the living environment and have a certain impact on the ecosystem structure and function. The objective of our study was to explore characters of present functional diversity indices, the relationships between functional diversity and environmental variables, the relevance of species diversity and functional diversity. In this paper, habitat type, seed dispersal, pollination method, life cycle, life form, leaf form, leaf hair type, flowering period and flowering time were chosen as functional traits, and the research were done in the typical forest communities in the Xiaowutai Mountain National Nature Reserve, Hebei. One hundred and forty-eight quadrats (10m×10m) of forest communities were established along altitude gradients, at the same time, species composition, functional traits, and environmental variables were measured in each quadrat. The results showed that functional diversity indices in forest communities that were calculated by functional distances varied greatly. Functional diversity indices (FAD, MFAD, FDp, FDc, FRic, Rao and FDis) had highly significantly positive correlation with Patrick index and showed a linear increasing trend. All the nine functional diversity indices (FAD, MFAD, FDp, FDc, FRic, Rao, FEve, FDiv, FDis) had significantly correlation with Shannon-Wiener index and Pielou index. Only FDiv showed significantly negative correlation, and the other eight functional diversity indices showed positive correlation. Environmental filtering was important to functional diversity pattern, and functional diversity indices showed correlation with environmental variables. Altitude was a significant factor to functional diversity in forest communities. Except for FDiv, other functional diversity indices displayed a decreasing trend along altitude gradients. Among all the functional diversity indices, only Rao and FDis showed significantly positive correlation with aspect. The functional diversity indices (FAD, MFAD, FDp, FDc, FRic, Rao and FDdis) showed a negative correlation with slope, slope position, litter layer thickness, soil thickness, while, they showed a positive correlation with soil temperature and disturbance. All the nine indices were proved successful in the analysis of functional diversity in forest communities with different effectiveness. They were divided into three categories, functional richness (FAD, MFAD, FDp, FDc, FRic), functional divergence (Rao, FDis), functional evenness (FEve, FDis). Meanwhile, each category was highly inter-correlated and each category was relatively independent with other categories. The study of functional diversity provides a number of ecological indication and monitoring methods for the forest, and it can address a wide range of important ecological questions that links species and ecosystems through mechanisms in biodiversity research.

Natural revegetation potential of Japanese wild thyme (Thymus quinquecostatus Celak.) on serpentine quarries

AbstractQuarrying is an important industry that supports human infrastructure, but it has negative effects on human health, environments, and plant communities. In the case of the serpentine quarry on Sugashima Island (Sugashima), Japan, rapid remediation using native plants is necessary to restore the serpentine ecosystem. According to our previous work, we revealed high adaptability of Japanese wild thyme (Thymus quinquecostatus Celak.) to the severe environment of serpentine areas, and we desired to utilize this species for revegetation. However, basic information on Japanese thyme was extremely limited, in comparison with well‐investigated European thymes that have been used for revegetation experiments. The aims of this work were to identify the plant functional traits of wild thymes collected from different areas of Japan and to test their potential for revegetation of serpentine quarry soil. We collected four types of wild thyme from Sugashima and other areas of serpentine, calcareous, and tuff breccia soil, and revealed varietal differences in leaf form, branching patterns, flowers, and also blooming season, seed formation ability, and seed germination percentages. Thymes from serpentine and calcareous areas could grow on soil of the serpentine quarry, and a small number of plants were able to cover the experimental plots. Among the Japanese thymes investigated, Sugashima thyme had the longest branches, and spread rapidly by forming many branches. These data suggest that Japanese thymes, especially Sugashima thyme, have good potential for revegetation of serpentine quarries.

Functional Genomics and Genetic Control of Compound Leaf Development in Medicago truncatula: An Overview.

Diverse forms of leaves are present in nature. However, the regulatory mechanisms that underpin the development of diverse leaf forms remain enigmatic. The initiation of leaf primordia from the periphery of shoot apical meristem (SAM) requires downregulation of the class 1 knotted-like homeobox KNOXI proteins. In plants with simple leaves, this downregulation is permanent, consistent with leaves being determinant organs. In most of plants with compound leaves, the KNOXI proteins are reactivated in developing leaf primordia, and this reactivation is required for the development of compound leaves in these plants. Surprisingly, in Medicago truncatula and pea (Pisum sativum) that belong to the so-called inverted repeat-lacking clade (IRLC) of legume plants, the KNOXI proteins are not reactivated in leaf primordia and therefore not likely involved in the development of compound leaves in these plants. Instead, the legume FLORICAULA/LEAFY orthologues, UNIFOLIATA (UNI) and SINGLE LEAFLET1 (SGL1), are required for the initiation and development of lateral leaflet primordia in pea and M. truncatula plants, respectively. On the other hand, PALMATE-LIKE PENTAFOLIATA1 (PALM1) encoding a novel Cys(2)His(2) zinc finger transcription factor is required to suppress a morphogenetic activity at the leaf margin by negatively regulating SGL1 gene expression, and FUSED COMPOUND LEAF1 (FCL1) encoding a class M KNOX protein is required for the development of the leaf proximo-distal axis and organ boundary separation in M. truncatula. Thus, these recent studies have shown that SGL1/UNI, FCL1, and PALM1 provide a genetic framework for our understanding of compound leaf development in the legume plants.

African violet (Saintpaulia ionantha H. Wendl.): classical breeding and progress in the application of biotechnological techniques

ABSTRACTAs a result of its domestication, breeding and subsequent commercialization, African violet (Saintpaulia ionantha H. Wendl.) has become the most famous and popular Saintpaulia species. There is interest in producing cultivars that have increased resistance to pests and low temperature, in the introduction of novel horticultural characteristics such as leaf shape, flower colour, size and form, and in improved productivity and enhanced flower duration in planta. In African violet, techniques such as the application of chemical mutagens (ethylmethanesulfonate, N-nitroso-N-methylurea), radiation (gamma (γ)-rays, X-rays, carbon ion beams) and colchicine have been successfully applied to induce mutants. Among these techniques, γ radiation and colchicine have been the most commonly applied mutagens. This review offers a short synthesis of the advances made in African violet breeding, including studies on mutation and somaclonal variation caused by physical and chemical factors, as well as transgenic strategies using Agrobacterium-mediated transformation and particle bombardment. In African violet, Agrobacterium-mediated transformation is affected by the Agrobacterium strain, selection marker, and cutting-induced wounding stress. Somaclonal variation, which arises in tissue cultures, can be problematic in maintaining true-to-type clonal material, but may be a useful tool for obtaining variation in flower colour. The only transgenic African violet plants generated to date with horticulturally useful traits are tolerant to boron (heavy metal) stress, or bear a glucanase-chitinase gene.

To be serrate or pinnate: diverse leaf forms of yarrows (Achillea) are linked to differential expression patterns of NAM genes.

To understand the link between species diversity and phenotype developmental evolution is an important issue in evolutionary biology. Yarrows in the genus Achillea (Asteraceae) show a great diversity in leaf serrate or pinnate dissection patterns. In Arabidopsis thaliana, the development of leaf serration requires the activity of the transcription factor CUC2. Does this regulator also work for leaf dissections of the Asteraceae plants? If so, how do the conserved regulatory 'tools' work differently to produce diverse leaf forms? Seedling leaf morphology was observed, and morphogenesis of leaf serration or lobes was examined by scanning electron microscopy (SEM). NAM genes, orthologues of arabidopsis CUC2, were isolated from A. acuminata with serrate leaves and A. asiatica with three-pinnatisect leaves, respectively. By means of whole-mount in situ mRNA hybridization and two quantitative gene expression assays, the droplet digital PCR (ddPCR) and quantitative real-time PCR (qPCR), expression patterns of the NAM genes during leaf dissection development were checked in both species for comparison. For both species, the development of leaf dissection initiated when a leaf blade was about 300-400 µm long. In A. acuminata, in situ hybridization showed NAM expression signals at leaf margins where teeth are growing, or later on, in the sinuses of the teeth, whilst in A. asiatica, hybridization signals appear not only on leaf margins but further on the margins of leaf lobes. Both ddPCR and qPCR revealed a continuous decline of AacNAM expression from the early to the late developmental stages of a single leaf of A. acuminata, whereas a relatively long maintenance and fluctuation of AasNAM expression was seen in a leaf of A. asiatica. Differential spatiotemporal patterns of NAM expression were found between the two yarrow species during development of leaf dissection. This study provides the first evidence for NAM activity in the development of leaf dissection of the Asteraceae plants, and demonstrates that leaf form diversity is correlated to the altered NAM expression dynamic.

Flavonoid Diversity and Morphological Variations Among Seven Phlomis Species in Zagros, Iran

This study investigates the variation of flavonoid patterns and morphological diversity among seven Phlomis species in the Zagros region of Iran. Morphological studies were carried out using 39 characters. The flavonoid compounds were extracted from leaves using methanol and thin-layer chromatography. To determine the flavonoid classes, column chromatography and ultraviolet absorption (200–400 nm) were applied. The taxonomic status, variation of flavonoid and morphological information were identified by cluster analysis with Simple Matching coefficient and NTSYS pc v.2.2. The morphological results revealed that Phlomis olivieri clearly exhibited high variations. A total of 31 flavonoids were found including 13 isoflavones, 15 flavones, two chalcones and one flavonol which is first reported in Iran. Cluster analysis of flavonoid profiles detected that the members of Phlomis sub-section Oxyphlomis and Phlomis sub-section Gymnophlomis were definitely characterized. Phlomis kurdica was strongly separated from Phlomis olivieri. In addition, Phlomis bruguieri displayed a close relationship with other members. High flavonoid variations were also detected in Phlomis olivieri, Phlomis anisodonta and Phlomis persica. It was proved that morphometric analysis was consistent with flavonoid results. Finally, both flavonoid markers and morphological characters such as leaf form, leaf base form, calyx teeth form, and calyx and stamen indumentum are valuable in classification of Phlomis species.

Inventarization Epiphytic Mosses in Hutan Lumut Area “Dataran Tinggi Yang”, Wildlife Preserve Argopuro Mountain

Mosses are group of non-vascular plant, small size, and able to growth in many substrates. Epiphytes are organism witch growth at wood surface of living plant. Epiphytic mosses has some advantages, there are out of range from terestial organism and to get more optimaly sun light. One of place which has suitable conditions for this research is in Wildlife Preserve “Dataran Tinggi Yang”, Argopuro Mountain. This research purpose to get known about species of epiphyte mosses and morphological characteristic each species of epiphytic mosses in Wildlife Preserve “Dataran Tinggi Yang”, Argopuro Mountain. The result of identification and characterization obtained 17 families and 25 species of epiphytic mosses. The main characteristic of mosses are leaf position, leaf form, and leaf costa.

Ethnobotanical study of medicinal plants used against human ailments in Gubalafto District, Northern Ethiopia

BackgroundTraditional medicinal plant species documentation is very crucial in Ethiopia for biodiversity conservation, bioactive chemical extractions and indigenous knowledge retention. Having first observed the inhabitants of Gubalafto District (Northern Ethiopia), the author gathered, recorded, and documented the human traditional medicinal plant species and the associated indigenous knowledge.MethodsThe study was conducted from February 2013 to January 2015 and used descriptive field survey design. Eighty-four informants were selected from seven study kebeles (sub-districts) in the District through purposive, snowball, and random sampling techniques. Both quantitative and qualitative data were collected through semi-structured interviews, guided field walks, demonstrations, and focus group discussions with the help of guided questions. Data were organized and analyzed by descriptive statistics with SPSS version 20 and Microsoft Office Excel 2007.ResultsA total of 135 medicinal plant species within 120 genera and 64 families were documented. Among the species, Ocimum lamiifolium and Rhamnus prinoides scored the highest informant citations and fidelity level value, respectively. In the study area, Asteraceae with 8.1% and herbs with 50.4% plant species were the most used sources for their medicinal uses. A total of 65 ailments were identified as being treated by traditional medicinal plants, among which stomachache (abdominal health problems) was frequently reported. Solanum incanum was reported for the treatment of many of the reported diseases. The leaf, fresh parts, and crushed forms of the medicinal plants were the most preferred in remedy preparations. Oral application was the highest reported administration for 110 preparations. A majority of medicinal plant species existed in the wild without any particular conservation effort. Few informants (about 5%) had only brief notes about the traditional medicinal plants. Ninety percent of the respondents have learned indigenous medicinal plants knowledge from their family members and friends secretly. Orthodox Church schools were found the main place for 65% of healer’s indigenous knowledge origin and experiences. Elders, aged between 40 and 84 years, gave detailed descriptions about traditional medicinal plants.ConclusionsTraditional medicinal plants and associated indigenous knowledge are the main systems to maintain human health in Gubalafto District. But minimal conservation measures were recorded in the community. Thus, in-situ and ex-situ conservation practices and sustainable utilization are required in the District.

AUXIN RESPONSE FACTOR3 Regulates Compound Leaf Patterning by Directly Repressing PALMATE-LIKE PENTAFOLIATA1 Expression in Medicago truncatula.

Diverse leaf forms can be seen in nature. In Medicago truncatula, PALM1 encoding a Cys(2)His(2) transcription factor is a key regulator of compound leaf patterning. PALM1 negatively regulates expression of SGL1, a key regulator of lateral leaflet initiation. However, how PALM1 itself is regulated is not yet known. To answer this question, we used promoter sequence analysis, yeast one-hybrid tests, quantitative transcription activity assays, ChIP-PCR analysis, and phenotypic analyses of overexpression lines and mutant plants. The results show that M. truncatula AUXIN RESPONSE FACTOR3 (MtARF3) functions as a direct transcriptional repressor of PALM1. MtARF3 physically binds to the PALM1 promoter sequence in yeast cells. MtARF3 selectively interacts with specific auxin response elements (AuxREs) in the PALM1 promoter to repress reporter gene expression in tobacco leaves and binds to specific sequences in the PALM1 promoter in vivo. Upregulation of MtARF3 or removal of both PHANTASTICA (PHAN) and ARGONAUTE7 (AGO7) pathways resulted in compound leaves with five narrow leaflets arranged in a palmate-like configuration. These results support that MtARF3, in addition as an adaxial-abaxial polarity regulator, functions to restrict spatiotemporal expression of PALM1, linking auxin signaling to compound leaf patterning in the legume plant M. truncatula.

Three Key Sub-leaf Modules and the Diversity of Leaf Designs.

Earth harbors a highly diverse array of plant leaf forms. A well-known pattern linking diverse leaf forms with their photosynthetic function across species is the global leaf economics spectrum (LES). However, within homogeneous plant functional groups such as tropical woody angiosperms or temperate deciduous woody angiosperms, many species can share a similar position in the LES but differ in other vital leaf traits, and thus function differently under the given suite of environmental drivers. How diverse leaves differentiate from each other has yet to be fully explained. Here, we propose a new perspective for linking leaf structure and function by arguing that a leaf may be divided into three key sub-modules, the light capture module, the water-nutrient flow module and the gas exchange module. Each module consists of a set of leaf tissues corresponding to a certain resource acquisition function, and the combination and configuration of different modules may differ depending on overall leaf functioning in a given environment. This modularized-leaf perspective differs from the whole-leaf perspective used in leaf economics theory and may serve as a valuable tool for tracing the evolution of leaf form and function. This perspective also implies that the evolutionary direction of various leaf designs is not to optimize a single critical trait, but to optimize the combination of different traits to better adapt to the historical and current environments. Future studies examining how different modules are synchronized for overall leaf functioning should offer critical insights into the diversity of leaf designs worldwide.

Correlation between leaf size and hydraulic architecture in five compound-leaved tree species of a temperate forest in NE China

The divergence between simple and compound leaf form is a fundamental division in leaf architecture that has great impact on environmental adaptations of plants. Two hypotheses regarding the adaptive significance of compound leaf form have long been hypothesized: (1) it enables trees to have higher growth rates under favorable environmental conditions; (2) it contributes to better adaptation to seasonal and unpredictable drought stresses since dropping the whole leaf units could function as a protective mechanism of hydraulic segmentation and hence avoiding diebacks of the more carbon costly stems. These hypotheses, however, have not been firmly supported by mechanistic studies on the underlying physiology and more importantly the inter-specific variations within this functional group in relation to these two proposed hypotheses have largely been overlooked. In the present study, using a common garden setup we investigated the impact of leaf size, an important characteristic of leaf architecture, on xylem hydraulics and carbon economy of five commonly found sympatric compound-leaved tree species from a typical temperate forest of NE China. We specifically tested the hypotheses that larger compound leaf size would be associated with higher hydraulic conductance, increased efficiency of carbon assimilation and greater degree of hydraulic segmentation. Our results showed that the majority of the hydraulic resistance in shoots was allocated to leaf lamina (53–77% among the five species) and the compound leaf petiole only accounts for a small portion of the shoot hydraulic resistance (9–24%). Both stem hydraulic conductivity and whole-shoot hydraulic conductance showed strong positive correlations with compound leaf size contributing to significantly higher carbon assimilation efficiency in species with larger leaf sizes. The magnitude of water potential drop across transpiring leaves showed a strong positive correlation with leaf size resulting in less negative stem xylem water potential in species with larger leaf sizes, which supports our hypothesis that larger compound leaf enhances hydraulic segmentation. Our results also showed that the advantages associated with larger leaf size can be traded off by a greater susceptibility to freeze-thaw induced hydraulic dysfunction. Besides a deeper understanding of the environmental adaptation of compound-leaved tree species, these findings may contribute to a better utilization of this important type of trees in forestry.

540 Acceptability of Spondia mombin Linn Leaves by West African dwarf (WAD) sheep in Ijebu-Ode local government, Ogun State, Nigeria

Evaluation of nutrient composition of browse forage under utilized as fodder by ruminants was carried out at the Tai Solarin University of Education, Ijagun. Ijebu-Ode. Ogun State. Nigeria. The objective of this work was to study the preference of different leaves (green, yellow and brown) of Spondia mombin by West African Dwarf Sheep (WAD). Eight female WAD sheep weighing 10 to 12 kg between the ages of nine months to one year were used in a fourteen day cafetaria feeding to assess the animals' preference profile for the green, yellow and brown leaves of Spondia mombin. During the fourteen day preference study, each of the forage (green, yellow and brown laeves) were served in separate container to allow each animal to have free access to each forage. The position of each container was changed every day to prevent animal's adaptation to a particular type of forage. The value of the Coefficient of preference (COP) for each leaf was calculated from the ratio between the intakes of each individual forage divided by the average intake of the forage. The result revealed that the value of COP of different leaf ranged from 1.85 – 2.05 in brown and green leaves respectively. The green leaf was mostly preferred. Samples from the feed refusal were taken to the laboratory to determine the chemical composition of green, yellow and brown leaves of Spondia mombin. Data generated were subjected to Analysis of Variance (ANOVA) and means were separated using Duncan's Multiple Range Test. Significance was accepted at 0.05 level of probability. The result showed that dry matter (DM), crude protein (CP), ether extract (EE), Ash, neutral detergent fiber (NDF) and acid detergent fiber differed significantly (P < 0.5) among the green, yellow and brown leaves. The highest value (90.22%) of Dry matter was recorded for the brown leaf, while the lowest value (85.05%) was recorded for the green leaf. The Crude protein ranged from 9.59 – 11.25% in brown and green leaves respectively, the green leaf had the lowest value (8.25%) of Ash, while the highest value (10.00%) was obtained in the brown leaf. Same trend was observed in EE, ADF and NDF. The Neutral detergent fiber ranged from 46.48-62.01% in green and brown leaves respectively. It can be concluded that Spondia mombin green, yellow and brown leaves has potential as forage in animal nutrition in this region as all leaf form were acceptable to the animals

Variance of light-related leaf traits across spatial and temporal scales in the Mediterranean evergreen Olea europaea L.

The variability in space and time of a given set of traits can describe the biological activity of plants and influence species interactions and the properties of communities and ecosystems. However, seasonal variance in foliar traits of tree species has been poorly addressed in the Mediterranean climate despite its potential implications in fundamental processes such as light interception strategies.Due to seasonal variation in the apparent sun path’s trajectory, predictable radiation patterns across crown positions may determine the variance partitioning for light-related leaf traits in evergreens. We hypothesize that in the most exposed part of the crown i.e. south, trait variance should be constraint due to abiotic stress compared to less exposed crown positions.We partitioned the variance across five nested scales for a set of traits that capture leaf form, structure, position relative to the sun and the potential area exposed in a given time in Olea europaea L. trees. The scales included temporal variation due to sampling in two different seasons and twelve spatially structured crown positions within trees. We conducted multivariate analyses to assess the variability among traits, within trees and among treesThe variance partitioning at the season scale was low and the structure conserved between seasons for most traits. Intraindividual variance was conspicuous for all traits evidencing a spatial gradient of trait distribution within trees from outer to inner layers and among paired crown sectors (North-East, South-West). Leaf angles and potential exposure to direct light had an absence of variance at scales above crown positions.The spatial distribution of crown sectors and layers had a distinct influence on the expression of leaf attributes among traits. Environmental filters may constrain variability on the outermost layer of the crown and on all crown positions during summer and winter, due to combination of the high irradiance and water stress in Mediterranean climates.