Leaf Anatomy

Plants are fundamentally important to life. Key research areas in plant science include plant species identification, weed classification using hyper spectral images, monitoring plant health and tracing leaf growth, and the semantic interpretation of leaf information. Botanists easily identify plant species by discriminating between the shape of the leaf, tip, base, leaf margin and leaf vein, as well as the texture of the leaf and the arrangement of leaflets of compound leaves. Because of the increasing demand for experts and calls for biodiversity, there is a need for intelligent systems that recognize and characterize leaves so as to scrutinize a particular species, the diseases that affect them, the pattern of leaf growth, and so on. We review several image processing methods in the feature extraction of leaves, given that feature extraction is a crucial technique in computer vision. As computers cannot comprehend images, they are required to be converted into features by individually analyzing image shapes, colors, textures and moments. Images that look the same may deviate in terms of geometric and photometric variations. In our study, we also discuss certain machine learning classifiers for an analysis of different species of leaves.

Rindyastuti R, Nurfadilah S, Rahadiantoro A, Hapsari L, Abywijaya IK. 2018. Leaf anatomical characters of four epiphytic orchids of Sempu Island, East Java, Indonesia: The importance in identification and ecological adaptation. Biodiversitas 19: 1906-1918. Leaf anatomy features are important characters to support species identification and classification, and they are related to ecological adaptation of species. The aims of the present study were: (i) to investigate leaf anatomical characters of four epiphytic orchids of Sempu Island (Ascochilus emarginatus, Dendrobium subulatum, Thrixspermum subulatum, and Thrixspermum acuminatissimum) in relation to the significance in species identification and ecological adaptation in coastal habitats of Sempu Island, (ii) to compare the adaptive ability of the four species in coastal habitats based on adaptive anatomical characters. The procedure of leaf anatomical studies as follows: orchid leaves were fixed in ethanol 70% and sliced into thin pieces with a microtome, and stained with 1% Safranin. The leaf anatomical organization of orchids (stomata, epidermis, mesophyll, vascular bundles, and other characters such as hypodermis, fibre bundles, raphide bundles, and spiral thickenings) was observed under light microscope. The results showed the comparable data of leaf anatomical characters among the orchids. There was distinct variation in the anatomical characters of the orchids including stomata anomocytic, tetracytic, and cyclocytic; the presence or absence of hypodermis, spiral thickenings, fibre bundles, raphide bundles, and bundle sheaths; homogenous and heterogenous mesophyll; and variation in vascular bundle arrangement. Detailed leaf anatomical characters can be used to distinguish a species from others, which are important to support species identification. The similarity of anatomical characters among these orchids were they possessed relatively thick cuticle and other specific anatomical characters as a structural adaptation to coastal habitat with high irradiation to reduce leaf transpiration. D. subulatum can be considered as the most adaptive orchid species to coastal habitats based on adaptive anatomical characters as it possessed the largest number of adaptive anatomical characters. The implication of this study is the importance of leaf anatomical features to support species identification and to increase understanding of orchid biology and ecology which are important in orchid conservation.

Better understanding of the functional biology of early angiosperms may clarify eco- logical factors surrounding their origin and early radiation. Phylogenetic studies identify Ambor- ella, Nymphaeales (water lilies), Austrobaileyales, and Chloranthaceae as extant lineages that branched before the radiation of core angiosperms. Among living plants, these lineages may rep- resent the best models for the ecology and physiology of early

Photosynthesis in C3 plants is significantly limited by mesophyll
conductance (gm), which can vary with leaf anatomical
traits and nitrogen (N) supplements. Several studies have
investigated the response of gm to N supplements; however,
none examined the implications of N supplements on the
response of gm to rapid environmental changes. Here we
investigated the effect of N supplement on gm and the
response of gm to change of CO2, temperature and irradiance
in rice. High N supplement (HN) increased mesophyll cell
wall surface area and chloroplast surface area exposed to
intercellular airspace per leaf area, and reduced cell wall
thickness. These changes resulted in increased gm. The gm of
leaves with HN was more sensitive to changes in CO2 concentration,
temperature and irradiance.The difference in leaf
structural features between low N supplement and HN indicates
that a rapid change in gm is related to the regulation of
diffusion through biological membranes rather than leaf
structural features. These results will contribute to an understanding of the determinants of gm response to rapid changes in environmental factors

The basis of differentiation between sun and shade leaves is related to different light intensities. In order to understand the adaptability of the leaves of Rhizophora mangle L., associated with different lighting conditions, leaves were collected from the upper peripheral six individuals (sun leaves) and the lower region of the same internal (shade leaves). The variables analyzed leaf thickness, palisade parenchyma, adaxial and abaxial epidermis, adaxial and abaxial cuticle, stomatal density and index. Measurements were made ??on microscope equipped with ocular micrometer. Sun leaves were lower and with more xeromorphic characteristics, such as increased thickness of the cuticle and the adaxial and abaxial epidermis. The palisade parenchyma and limbus showed up thicker than shade leaves, with no significant difference between the cuticle of the abaxial surface. It was also observed a higher frequency of stomata per mm², an average of 70/mm², while shade leaves showed 47/mm², with no differences between length and width. Differences between the sun leaves and shade leaves indicate adaptive capacity of this species to remain active at different light conditions.

A simple method using the O2 electrode that allows examination of the response of respiration and photosynthesis in leaf slices or algae to anoxia and high light under different temperatures useful for the examination of the interactions among photosynthesis, photorespiration, and respiration is described. The method provides a quantifiable assessment of stress tolerance that also permits us to examine fundamental biochemically and genetically related responses involved in stress tolerance and the cooperation among organelles. Additionally, we demonstrated a role for compounds, such as $ {\text{NO}}^{{\text{ - }}}_{{\text{3}}} $ and oxaloacetate, as protective agents against photoinhibition, and we examined the role of dark adaptation in the activation of photosynthesis and $ {\text{NO}}^{{\text{ - }}}_{{\text{3}}} $ -dependent O2 oxygen evolution. A physiological and ecological role of a dark period (night) in stress tolerance is presented. Utilizing the method to follow changes in such metabolic activities as protein synthesis, protein conformation states, enzymes activity, carbon metabolism, and gene expression at different points during the treatments will be educational.

Solvent leaf extracts of Terminalia catappa were evaluated for
their cytotoxic and their radical scavenging potential. Brine shrimp
assay was used for exploring cytotoxic activity, all the extracts
namely hexane, DCM, chloroform, acetone and methanol were
tested at the dose level of 25, 50, 100 and 200microgram /ml. A
dose dependent response was obtained in all the extracts.
Chloroform extract showed 100percent activity at the highest dose
of 200μg/ml. Antioxidant activity was evaluated by one
qualitative(TLC based) and two quantitative radical scavenging
assays namely DPPH (2, 2- Diphenyl-1- picryl hydrazyl) assay
and ferric reducing antioxidant power (FRAP) assay. In both
assays acetone extract exhibited significant reduction of free
radicals. The IC50 value of acetone extract was 36.9μg/ml.
Ascorbic acid was used in these assays as reference compound.
FRAP value of acetone extract was found to be 6.73 much higher
than all the other extracts.

• Premise of the study : Leaves at the tops of most trees are smaller, thicker, and in many other ways different from leaves on the lowermost branches. This height-related variation in leaf structure has been explained as acclimation to differing light environments and, alternatively, as a consequence of hydrostatic, gravitational constraints on turgor pressure that reduce leaf expansion.
• Methods : To separate hydrostatic effects from those of light availability, we used anatomical analysis of height-paired samples from the inner and outer tree crowns of tall redwoods ( Sequoia sempervirens ).
• Key results : Height above the ground correlates much more strongly with leaf anatomy than does light availability. Leaf length, width, and mesophyll porosity all decrease linearly with height and help explain increases in leaf-mass-to-area ratio and decreases in both photosynthetic capacity and internal gas-phase conductance with increasing height. Two functional traits — leaf thickness and transfusion tissue — also increase with height and may improve water-stress tolerance. Transfusion tissue area increases enough that whole-leaf vascular volume does not change signifi cantly with height in most trees. Transfusion tracheids become deformed with height, suggesting they may collapse under water stress and act as a hydraulic buffer that improves leaf water status and reduces the likelihood of xylem dysfunction.
• Conclusions : That such variation in leaf structure may be caused more by gravity than by light calls into question use of the terms “ sun ” and “ shade ” to describe leaves at the tops and bottoms of tall tree crowns.

Hypermetamorphosis has been described in several Lepidoptera leaf-miner species (mostly Gracillariidae, Epipyropidae, and Phyllocnistidae) and can be defined as a strong modification of the larval morphology associated with a switch in its feeding mode. Evolution of this larval feeding strategy presumably influences nutritional resources that can be exploited and has strong consequences for plant morphology. The following study focuses on Phyllonorycter blancardella (Lepidoptera: Gracillariidae), a leaf-miner developing on Malus domestica. We characterize the morphology of larval mouthparts and the resulting morphological impact on leaf tissues. Our results show that first instars do not strongly affect the leaf anatomy and leave most plant cells intact, while later instars significantly disrupt leaf tissues. Additionally, young larvae are “fluid-feeders” and feed on plant cell fluids resulting from the progression of the larvae through the lower layer of the leaf spongy parenchyma. They occupy a feeding niche clearly distinct from later instars that are “tissue-feeders”. Hypermetamorphosis in P. blancardella most likely allows insects to cope with a confined nutritional space by partitioning the limited feeding resources, and may help leaf-miners to optimize their nutrition.