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Leaf mass per area (LMA) has been suggested to negatively affect the mesophyll conductance to CO2 (g m), which is the most limiting factor for area-based photosynthesis (A N) in many Mediterranean sclerophyll species. However, despite their high LMA, these species have similar A N to plants from other biomes. Variations in other leaf anatomical traits, such as mesophyll and chloroplast surface area exposed to intercellular air space (S m/S and S c/S), may offset the restrictions imposed by high LMA in g m and A N in these species. Seven sclerophyllous Mediterranean oaks from Europe/North Africa and North America with contrasting LMA were compared in terms of morphological, anatomical and photosynthetic traits. Mediterranean oaks showed specific differences in A N that go beyond the common morphological leaf traits reported for these species (reduced leaf area and thick leaves). These variations resulted mainly from the differences in g m, the most limiting factor for carbon assimilation in these species. Species with higher A N showed increased S c/S, which implies increased g m without changes in stomatal conductance. The occurrence of this anatomical adaptation at the cell level allowed evergreen oaks to reach A N values comparable to congeneric deciduous species despite their higher LMA.

The role of ionic excretions and hyper-accumulation of salts through alterations of structural and functional traits in five populations of Suaeda vera Forssk. ex J.F. Gmel., a halophytic salt-indicator species of saline environments, was explored. Differently adapted populations of S. vera exhibited specific structural and functional responses for the survival in hyper-saline conditions. Better growth in population from moderately saline habitat (25–30 dS m −1 ) was linked to high shoot and root K + and increased ion selectivity (K + /Na + and Ca 2+ /Na + ). Increased excretion of Na + and Cl − with increasing salinity level was a critical mechanism in maintaining ionic balance. Drastic differences were observed for anatomical characteristics in populations inhabiting differentially salt-affected lands. The plants from highly saline sites were characterized by narrow metaxylem vessels, low proportion of cortical parenchyma, and reduced phloem area leading to stunted growth. Contrariwise, root area significantly increased due to high proportion of sclerified xylem tissue, which was associated with easier conduction of solutes and protection of roots from collapsing. Root sclerification particularly at the highest salinity regime was a key factor in the survival of this species in salt-affected compact soils. Leaf anatomical characteristics showed reduction with increasing salinity, but the leaf thickness responded otherwise. This contributed to increased leaf succulence because of high proportion of storage parenchyma in populations colonizing hyper-saline habitats. It was concluded that moderate salinity conditions were more suitable for the growth of S. vera, though some populations of this species were able to tolerate much higher salinity levels.

Soil salinity and water deficit often occur concurrently, but understanding their combined effects on plants’ ion regulation is limited. With aim to identify if introducing drought with salinity alleviates salt stress’s ionic effects, Panicum antidotale – a halophytic grass- was grown in the presence of single and combined stressors, i.e., drought and salt (low and high). Regulation of cations and anions along with the antioxidant capacity and modifications in leaf anatomy were investigated. Results showed a combination of low salt and drought minimally affected plant (dry) mass by improving the selective ions absorption and nutrient use efficiencies. The lowest ratio for efficiency of photosystem II and carbon assimilation (ΦPSII/ΦCO 2 ) suggested less generation of reactive oxygen species, which were probably detoxified with constitutively performing antioxidant enzymes. In contrast, the combination of high salinity and drought escalated the adverse effects caused due to individual stressors. The selective ion absorption increased, but the non-selective ions transport caused an ionic imbalance indicating the highest ratio of Na + /K + . Although the area of mesophyll increased, a reduction in epidermis (cell number and area) predicted a mechanical injury prone to water loss in these plants. The compromised activity of antioxidant enzymes also suggested treatment-induced oxidative damage. Yet, the synergistic interaction between high salinity and drought was not detrimental to the survival of P. antidotale. Therefore, we suggest planting this grass in habitats with harsh environmental conditions to meet the increasing fodder demands without compromising agricultural lands’ productivity.

Fimbristylis complanata manifests several biochemical and anatomical modifications to mitigate salinity-induced ionic disturbance. Three populations from salt-affected aquatic habitats were evaluated to assess degree of salinity tolerance and ion homeostasis. The collection sites were HR-Rasool headworks, LR-Lillah-Khewra foothills and SH-Sahianwala with ECe 19.45, 31.36 and 47.49 dS m−1, respectively. The populations were established in plastic containers and then three salt (NaCl) treatments (0, 200, 400 mM) were maintained. The experiment was laid in a completely randomized design (CRD) with three replicates. The SH population collected from hyper-saline habitat was the most salt tolerant mainly because of its capability to maintain root and shoot dry biomass accompanied by higher sequestration of Na+. Enhanced accumulation of Ca2+ and other key osmolytes in SH population played a key role in osmotic adjustments and maintenance of membrane integrity. The reduction in tissue K+ was observed in all populations due to the antagonistic effect of Na+. Anatomical traits like increased epidermal thickness and metaxylem area greatly contributed to ionic homeostasis in all three populations. The increase in anatomical traits was more pronounced in SH population. Increased leaf epidermal thickness in SH population was particularly helpful in tolerating low soil osmotic potentials by preventing water loss from the leaves. Increased aerenchyma in SH same population helped to store surplus water, salts and gases. These findings suggested that F. complanata exhibited enhanced salt tolerance by regulating the ion homeostasis and osmoregulation through a variety of morphological, biochemical and anatomical features.

Fusarium wilt (FW), induced by Fusarium oxysporum, poses a significant threat to global tomato (Solanum lycopersicum L.) production, leading to substantial yield reduction. This study investigated the anatomical and ultrastructural responses of tomato leaves to FW infection and assessed the efficacy of salicylic acid (SA), humic acid (HA), and zinc oxide nanoparticles (ZnO-NPs) as control and inducer agents. FW infection resulted in notable structural alterations, including decreased leaf blade and mesophyll thickness and increased Adaxial epidermal cell wall thickness, thereby disrupting the leaf structure. Also, it caused severe chloroplast damage, such as membrane detachment and a reduced count of starch granules, which could impair photosynthetic efficiency. The different treatments exhibited significant effectiveness in reversing these adverse effects, leading to increased thickness of the leaf blade, mesophyll, palisade, and spongy tissues and enhanced structural integrity. Furthermore, ultrastructural improvements included activated mitochondria, compact chloroplasts with increased numbers, and proliferation of plastoglobuli, indicating adaptive metabolic changes. Principal component analysis (PCA-biplot) highlighted the significant parameters distinguishing treatment groups, providing insights into trait-based differentiation. This study concluded the potential of SA, HA, and ZnO-NPs as sustainable solutions for managing Fusarium wilt and enhancing tomato plant resilience, thereby contributing to improved agricultural practices and food security.

Despite the great variety of habitats in Madagascar, Eulemur has successfully populated most forested habitats on the island. Although the high dietary flexibility of Eulemur is often credited as one of the drivers of its evolutionary success, other behavioral evidence suggests a limited capacity for dietary switching. To shed light on the feeding strategies of Eulemur , we compared the dietary flexibility between populations of this genus with that of another widespread lemur taxon, Propithecus . We hypothesized that Eulemur would show greater dietary flexibility than Propithecus , which has a digestive system specialized for folivory, and that Eulemur living in dry forests would switch its diet from fruit to other food seasonally. To examine these hypotheses, we performed a phylogenetic least-squares analysis on 10 populations of Eulemur and 7 of Propithecus to assess the contribution of environmental variables and body mass on their dietary flexibility while controlling for phylogenetic relatedness. Eulemur relied heavily on fruit and did not show large variations in primary food over the year. Propithecus consumed leaves and fruits equally and exhibited considerable flexibility across seasons. Therefore, in contrast to our predictions, the anatomical specialization for fiber digestion heightens dietary flexibility in Propithecus . At the intrageneric level, we found similar ecogeographic variation; populations of both genera with heavier body mass consumed more fruit. As we predicted, Eulemur in drier habitats switched the diet from fruit to alternative food more frequently. To compensate for low dietary flexibility, Eulemur mostly adopts a power-feeding strategy by which it increases energy expenditure to acquire patchily distributed fruit resources.

Pumpkin is an important economic crop with high nutritional value. Different pumpkin varieties experience diverse growth problems due to soil salinity. This research studied the physiological and anatomical adaptations of the Kang Kog pumpkin cultivar to salinity stress. Pumpkin seedlings were grown under a hydroponic system using Hoagland’s solution with NaCl concentrations of 0 mM, 25 mM, 50 mM, 75 mM and 100 mM for four weeks. Results showed that pumpkin leaf number, leaf width, leaf length, root number, root length, plant height, stem diameter, fresh weight and dry weight significantly decreased after exposure to high NaCl concentrations. Chlorophyll a and green intensity measured as SPAD units also significantly decreased, while chlorophyll fluorescence (Fv/Fm, Fv’/Fm’) and chlorophyll b content of all treated groups were not significantly different when compared to the control group. Fibre strands and cuticles in all treatments were significantlythicker compared to the control group, while vessel diameters and vascular bundle sizes of the treated groups significantly decreased compared to the control group. Results showed that salinity stress did not impact chlorophyll b and chlorophyll fluorescence. Kang Kog pumpkins can adapt and grow in slightly saline environments. Our results provide important information for pumpkin breeding programs efforts that can be used in combining with other agronomic characters to improve tolerant cultivars under initial salinity stress tolerance.

The table olive cultivar ‘Meski’ was subjected to two stresses related to water, scarcity, and salinity. Anatomical adaptations of leaves, stems and roots were studied and compared, to value the water use efficiency of the tree. Two stress levels were adopted corresponding to moderate and severe levels. Thus, the trees behaviour was influenced by the stress type and intensity. The aerial part of the trees showed more adaptation modes than the underground part. Under both stresses, plants have fortified the protection of the leaf tissues by developing upper envelope and multiplying the trichomes. Plants reinforced the support tissues by multiplying the collenchyma and sclereids, and have amplified the transport tissues by enhancing vascularity through multiplying the number of conductive vessels. However, different behaviours seemed to be specific to each stress such an enlargement of liber and reduction of wood in the drought stress and a restriction of liber and wood tissues in salt stress. Additionally, a retraction of the palisade parenchyma and an extension of the spongy parenchyma in drought stress inversely to salt stress were noted. In the treated stems and roots, development of stomata, suber, pericyclic fiber and liber, and a restriction of wood especially in severe stress were observed. The plants developed important changes in moderate stresses; however, in the severe, the plants seemed to be stressed, by presenting no significant changes relatively to the control.

Drought stress can affect significant productivity and quality attributes in rice. This research assessed the impact of drought stress on the physiological and anatomical adaptations of ‘Tubtim Chumphae’ rice. Seedlings were cultivated for 45 days in soil before being subjected to drought stress. The seedlings were divided into two groups as full water capacity treatment and drought stress treatment for 21 days before rewatering for 10 days. Dehydration from drought stress reduced rice seedling plant height, tiller number, leaf size, and fresh and dry weight while leaf rolling score increased. The recovery process from drought stress impacted the physiological characteristics. Relative water content and chlorophyll fluorescence decreased while green intensity (SPAD value), chlorophyll content, electrolyte leakage percentage, and malondialdehyde (MDA) content increased. Anatomical studies using free-hand section and peeling techniques revealed that water deficit reduced vascular bundle size, bulliform cell size, stomatal size, and epidermal cell (short cell) size while leaf thickness, cuticle and cell wall thickness and bulliform cell number increased. Our results provide useful information on rice seedling adaptation and response to drought for use in further studies of ‘Tubtim Chumphae’ rice and other cultivars.

This review focused on some specific histo-physiological features of the mangroves that help them to adjust and grow extensively in the saline rich coastal regions. Sundarban, the largest chunk of coastal ecosystems of the world located between India and Bangladesh has the widest range of mangrove species in its tidal influenced highly saline soil. Several anatomical characteristics to conserve water are mostly species specific and unique to these plants as such characteristics are not found in their genetically close relatives. The most conspicuous features are succulent leaves with increased mesophyll area, thick cuticle and wax deposition on epidermis. Chlorenchyma cells with large vacuoles are often found associated with different forms of salt secreting glands. A cavitation resistant xylem structure in the stem is one of the mechanisms of mangroves to safeguard their water transport. Non-annual growth ring in some mangroves could be a potential proxy for past environmental conditions. Most root systems show reduced cortex with aerenchyma but wider casparian strip. These anatomical characteristics are the basis for their physiological adaptation to high saline condition. Mangroves can regulate ion homeostasis under salt stress by salt secretion, ultrafiltration and ion sequestration. Salinity stress leads to accumulation of reactive oxygen species (ROS), peroxidation of membrane lipids and inactivation of proteins. Mangroves can activate diverse components of their antioxidative system to eliminate H 2 O 2 and restrict the accumulation of ROS. All these characteristics help the mangroves to photosynthesize optimally and show a good vegetative growth under tidal influenced varied saline condition.