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Tree leaves are important food sources for arboreal herbivores, such as primates, rodents, and marsupials. These animals do not eat leaves randomly in habitats with many tree species but rather choose based on the chemical components of leaves, such as sugars, fibers, proteins, and toxins. However, the effects of the microscale distribution of these chemicals within each leaf have not been examined for these animals. The giant flying squirrels Petaurista leucogenys are entirely arboreal, nocturnal herbivores, usually feeding on leaves and dropping leaf debris on the ground after partially consuming them. Therefore, we could easily assess which species of trees and which parts of the individual leaves they preferred to eat. We also examined microscale distributions of phenolics, sugar, and water within individual leaves. Of the two dominant food tree species, the deciduous Quercus acutissima was preferred over the evergreen Q. sessilifolia. The latter tree is only used during winter to early spring when the former had no leaves. Our chemical analyses revealed that Q. acutissima contained much more glucose than Q. sessilifolia in all seasons. Three types of leaf debris, eaten apically, basally, or centrally with a hole, were found. In Q. sessilifolia, which had low phenolic concentrations, apical eating was most common, whereas central eating was rare. In Q. acutissima, which had high phenolics, basal or central eating was common. Central feeding may be caused by avoiding the periphery because of a higher phenolic concentration in the leaf margin. Thus, microscale distributions of phenolics within individual leaves affect which parts P. leucogenys eats, whereas leaf sugar concentration is an important factor affecting which species of leaves they eat. The Japanese giant flying squirrels leave three types of leaf debris, eaten apically (Type A), basally (Type B), or centrally with a hole (Type C). Microscale distributions of chemicals within individual leaves revealed that phenolic concentrations affect which parts the flying squirrels eat, whereas sugar concentration is an important factor affecting which species they eat.

The Great Lakes spiny reed frog ( Afrixalus lacustris ) was recently described from transitional (submontane) forests at mid-elevations of the Albertine Rift mountains in the eastern Congolian region. Previously, because of its similarity, it had been understood to represent eastern populations of the unrelated A. laevis , which is known mainly from Cameroon. Based on DNA barcoding, we document the westward extension of the known range of A. lacustris within lowland rainforests in the Northeastern and Central Congolian Lowland Forests. One sample was represented by a larva found in a clutch in a folded leaf, a typical oviposition type for most Afrixalus species, contrary to oviposition on an unfolded leaf surface in the similar A. laevis and closely related A. dorsimaculatus and A. uluguruensis . Comparison of the advertisement call of A. lacustris from Salonga National Park, Democratic Republic of the Congo, indicates similarity to its sister species from montane areas of the Albertine Rift, the ghost spiny reed frog ( A. phantasma ). Phylogeographic analysis suggests that A. phantasma and A. lacustris speciated allopatrically during the Early Pleistocene, with the former having refugia in montane forests and the latter in transitional and also lowland forests. The lowland populations of A. lacustris represent distinct evolutionary lineages, which diversified probably in isolated forest refugia during the Middle Pleistocene.

Craterostigma plantagineum tolerates extreme desiccation. Leaves of this plant shrink and extensively fold during dehydration and expand again during rehydration, preserving their structural integrity. Genes were analysed that may participate in the reversible folding mechanism. Analysis of transcripts abundantly expressed in desiccated leaves identified a gene putatively coding for an apoplastic glycine-rich protein (CpGRP1). We studied the expression, regulation and subcellular localization of CpGRP1 and its ability to interact with a cell wall-associated protein kinase (CpWAK1) to understand the role of CpGRP1 in the cell wall during dehydration. The CpGRP1 protein accumulates in the apoplast of desiccated leaves. Analysis of the promoter revealed that the gene expression is mainly regulated at the transcriptional level, is independent of abscisic acid (ABA) and involves a drought-responsive cis-element (DRE). CpGRP1 interacts with CpWAK1 which is down-regulated in response to dehydration. Our data suggest a role of the CpGRP1–CpWAK1 complex in dehydration-induced morphological changes in the cell wall during dehydration in C. plantagineum. Cell wall pectins and dehydration-induced pectin modifications are predicted to be involved in the activity of the CpGRP1–CpWAK1 complex.

Resurrection plants have fascinated scientists since centuries as they can fully recover from cellular water contents below 10%, concomitantly showing remarkable leaf folding motions. While physiological adaptations have been meticulously investigated, the understanding of structural and mechanical adaptations of this phenomenon is scarce. Using imaging and bending techniques during dehydration-rehydration experiments, morphological, anatomical, and biomechanical properties of desiccation-tolerant are examined, and selected structural adaptations are compared to those of homoiohydrous (both Gesneriaceae). At low water availability, intact and cut-off leaves undergo considerable morphological alterations, which are fully and repeatedly reversible upon rehydration. Furthermore, their petioles show a triphasic mechanical behavior having a turgor-based structural stability at high (Phase 1), a flexible mechanically state at intermediate (Phase 2) and a material-based stability at low water contents (Phase 3). Lastly, manipulation experiments with cut-off plant parts revealed that both the shape alterations of individual structures, as well as, the general leaf kinematics largely rely on passive swelling and shrinking processes. Taken together, possesses structural and mechanical adaptations to desiccation (in addition to physiological adaptations), which may mainly be passively driven by its water status influenced by the water fluctuations in its surroundings.

Premise of the study: How leaf shape is regulated is a long-standing question in botany. For diverse groups of dicotyledon species, lamina folding along the veins and geometry of the space available for the primordia can explain the palmate leaf morphology. Dubbed the kirigami theory, this hypothesis of fold-dependent leaf shape regulation has remained largely theoretical. Using Acer pseudoplatanus, we investigated the mechanisms behind the two key processes of kirigami leaf development. Methods: Cytological examination and quantitative analyses were used to examine the course of the vein-dependent lamina folding. Surgical ablation and tissue culturing were employed to test the effects of physical constraints on primordia growth. The final morphology of leaves growing without steric constraints were predicted mathematically. Key results: The cytological examination showed that the lamina's abaxial side along the veins grows substantially more than the adaxial side. The abaxial hypergrowth along the veins and the lamina extension correlated with the lamina folding. When a primordium was released from the physical constraints imposed by the other primordia, it rapidly grew into the newly available space, while maintaining the curvature inward. The morphology of such a leaf was predicted to lack symmetry in the lobe shapes. Conclusions: The enhanced growth on the abaxial side of the lamina along the veins is likely to drive lamina folding. The surgical ablation provided clear support for the space-filling nature of leaf growth; thus, steric constraints play a role in determination of the shapes of folded leaves and probably also of the final leaf morphology.

Extreme high-temperature events are the key factor to determine population dynamics of the rice leaf folder, Cnaphalocrocis medinalis (Guenée), in summer. Although we know that adult of this insect can migrate to avoid heat stress, the behavioral response of larva to high temperature is still unclear. Therefore, impacts of high temperature on behavioral traits of C. medinalis including host choice, settling and folding leaf were observed. The results revealed that these behavioral traits were clearly influenced by high temperature. The larvae preferred maize leaves rather than rice and wheat at normal temperature of 27°C, but larvae experienced a higher temperature of 37 or 40°C for 4 h preferred rice leaves rather than maize and wheat. Capacity of young larvae to find host leaves or settle on the upper surface of leaves significantly reduced when they were treated by high temperature. High temperature of 40°C reduced the leaf-folding capacity of the third instar larvae, but no effects were observed on the fourth and fifth instar larvae. Short-term heat acclimation could not improve the capacity of the third instar larvae to make leaf fold under 40°C.

BACKGROUND AND AIMS: In tropical lowland rain forest (TLRF) the leaves of most monocots differ from those of most dicots in two ways that may reduce attack by herbivores. Firstly, they are tougher. Secondly, the immature leaves are tightly folded or rolled until 50-100 % of their final length. It was hypothesized that (a) losses of leaf area to herbivorous invertebrates are generally greatest during leaf expansion and smaller for monocots than for dicots, and (b) where losses after expansion are appreciable any difference between monocots and dicots then is smaller than that found during expansion. METHODS: At six sites on four continents, estimates were made of lamina area loss from the four most recently mature leaves of focal monocots and of the nearest dicot shoot. Measurements of leaf mass per unit area, and the concentrations of water and nitrogen were made for many of the species. In Panama, the losses from monocots (palms) and dicots were also measured after placing fully expanded palm leaflets and whole dicot leaves on trails of leaf-cutter ants. KEY RESULTS: At five of six sites monocots experienced significantly smaller leaf area loss than dicots. The results were not explicable in terms of leaf mass per unit area, or concentrations of water or nitrogen. At only one site was the increase in loss from first to fourth mature leaf significant (also large and the same in monocots and dicots), but the losses sustained during expansion were much smaller in the monocots. In the leaf-cutter ant experiment, losses were much smaller for palms than for dicots. CONCLUSIONS: The relationship between toughness and herbivory is complex; despite the negative findings of some recent authors for dicots we hypothesize that either greater toughness or late folding can protect monocot leaves against herbivorous insects in tropical lowland rain forest, and that the relative importance varies widely with species. The difficulties of establishing unequivocally the roles of leaf toughness and leaf folding or rolling in a given case are discussed.

Nest building by leaf folding is a rare behaviour in anuran amphibians, with previous reports for only two genera, the Subsaharan African Afrixalus, and Central and South American Phyllomedusa. This communication reports a specialized nest building behaviour of an Indian treefrog Rhacophorus lateralis, which was observed in natural habitat at Kalpetta in Wayanad District, Kerala. This behaviour of leaf folding is the first report in the family Rhacophoridae, and in the Asiatic amphibians. Nesting behaviour of R. lateralis is unique among Rhacophorus – a purse-like nest is made over water by folding a single leaf around the egg mass (embryos and translucent foam) by the female alone after oviposition. The function of this parental investment is to prevent desiccation of eggs in open sunlight. This paper also documents the multiple leaf nesting behaviour of other two species of this genus, R. calcadensis and R. pseudomalabaricus, and the previously documented nesting behaviour of R. malabaricus using more than one leaf.

Summary Leaf‐surface properties were investigated in F. rubra ssp. litoralis (G. F. W. Meyer) Auquier cv. Hawk, which is tolerant of salt spray, and cv. Aberystwyth S.59, which is susceptible. Salt retention and leaf wettabilities were measured and leaf‐surface structure was observed using a scanning electron microscope. In both cultivars stomata were confined to adaxial leaf surfaces which were less wettable than abaxial surfaces probably because of ridging and wax deposits. Salt retention after spraying was much higher per unit dry weight in S.59 than in Hawk, although salt retention per unit of projected leaf area was similar in both cultivars. This was because leaves were folded about the midrib in Hawk but were much flatter in S.59. Folding reduced the exposure of adaxial leaf surfaces to salt spray. The adaptative significance of this is discussed together with its broader physiological implications.

Drought and waterlogging seriously affect the growth of plants and are considered severe constraints on agricultural and forestry productivity; their frequency and degree have increased over time due to global climate change. The morphology, photosynthetic activity, antioxidant enzyme system and hormone levels of plants could change in response to water stress. The mechanisms of these changes are introduced in this review, along with research on key transcription factors and genes. Both drought and waterlogging stress similarly impact leaf morphology (such as wilting and crimping) and inhibit photosynthesis. The former affects the absorption and transportation mechanisms of plants, and the lack of water and nutrients inhibits the formation of chlorophyll, which leads to reduced photosynthetic capacity. Constitutive overexpression of 9-cis-epoxydioxygenase (NCED) and acetaldehyde dehydrogenase (ALDH), key enzymes in abscisic acid (ABA) biosynthesis, increases drought resistance. The latter forces leaf stomata to close in response to chemical signals, which are produced by the roots and transferred aboveground, affecting the absorption capacity of CO2, and reducing photosynthetic substrates. The root system produces adventitious roots and forms aerenchymal to adapt the stresses. Ethylene (ETH) is the main response hormone of plants to waterlogging stress, and is a member of the ERFVII subfamily, which includes response factors involved in hypoxia-induced gene expression, and responds to energy expenditure through anaerobic respiration. There are two potential adaptation mechanisms of plants (“static” or “escape”) through ETH-mediated gibberellin (GA) dynamic equilibrium to waterlogging stress in the present studies. Plant signal transduction pathways, after receiving stress stimulus signals as well as the regulatory mechanism of the subsequent synthesis of pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH) enzymes to produce ethanol under a hypoxic environment caused by waterlogging, should be considered. This review provides a theoretical basis for plants to improve water stress tolerance and water-resistant breeding.