Photosynthetic Efficiency Research Articles

AMF-mediated salinity adaptation in Pistachio plants: photosynthetic efficiency and ionic balance

AMF-mediated salinity adaptation in Pistachio plants: photosynthetic efficiency and ionic balance

Temperature-enhanced effects of iron on Southern Ocean phytoplankton

Abstract. Iron (Fe) is a key limiting nutrient for Southern Ocean phytoplankton. Input of Fe into the Southern Ocean is projected to change due to global warming, yet the combined effects of a concurrent increase in temperature with dissolved Fe (dFe) addition on phytoplankton growth and community composition have not been extensively studied. To improve our understanding of how Antarctic phytoplankton communities respond to Fe and enhanced temperature, we performed four full factorial onboard bioassays under trace-metal-clean conditions with phytoplankton communities from different regions of the Weddell Sea and the Amundsen Sea in the Southern Ocean. Treatments consisted of 2 nM Fe addition with 2 °C warming (TF), Fe addition at in situ temperature (F) +2 °C warming with no Fe addition (T) and a control at in situ temperature with no Fe addition (control, C). Temperature had a limited effect by itself but boosted the positive response of the phytoplankton to Fe addition. Photosynthetic efficiency, phytoplankton abundances and chlorophyll a concentrations typically increased (significantly) with Fe addition (F and/or TF treatment), and the phytoplankton community generally shifted from haptophytes to diatoms upon Fe addition. The < 20 µm phytoplankton fraction displayed population-specific growth responses, resulting in a pronounced shift in community composition and size distribution (mainly towards larger-sized phytoplankton) for the F and TF treatments. Such a distinct enhanced impact of dFe supply with warming on Antarctic phytoplankton size, growth and composition will likely affect trophic transfer efficiency and ecosystem structure, with potential significance for the biological carbon pump.

Plant growth regulators improve the yield of white lupin (Lupinus albus) by enhancing the plant morpho-physiological functions and photosynthesis under salt stress

BackgroundWhite lupin (Lupinus albus L.) is a multi-purpose, climate resilient, pulse crop with exceptionally high protein content that makes it a suitable alternative of soybean in livestock feed. Although white lupin grows well on marginal sandy soils, previous studies have reported its sensitivity towards salinity stress. This experiment aims to assess the influence of salinity stress and mitigating role of plant growth regulators (PGRs) on performance of white lupin.MethodologyThe white lupin plants were sown in pots maintained at three salinity levels (1, 3 and 4.5 dS m− 1) throughout the growing season and foliar sprayed with different PGRs, including ascorbic acid, potassium chloride, boric acid, ammonium molybdate and methionine at sowing, four weeks after emergence and at the initiation of flowering. Foliar spray of distilled water and salinity level of 1 dS m− 1 were maintained as control treatments. Data were recorded for seed germination indices, plant growth, antioxidant enzymes and photosynthetic efficiency variables.ResultsThe severe salinity stress (4.5 dS m− 1) reduced the germination indices by 9–50%, plant growth traits by 26–54%, root nodulation by 12–26%, grain development by 44–53%, antioxidant enzymes activity by 13–153% and photosynthetic attributes by 1–8% compared to control (1 dS m− 1). Different PGRs improved several morpho-physiological attributes in a varied manner. The application of potassium chloride improved seed vigour index by 53%, while ascorbic acid improved root nodulation by 12% and number of pods per cluster by 75% at the severe salinity level. The foliar application of PGRs also displayed a recovery of 140% in the activity of superoxide dismutase and 70% in catalase. The application of multi zinc displayed an improvement of 37% in plant relative chlorophyll, while ascorbic acid brought an increase of 25% in non-photochemical quenching and 21% in photochemical quenching coefficient at the severe salinity level. On contrary, the application of PGRs brought a relatively modest improvement (8–13%) in quantum yield of photosystem II at slight to moderate (3 dS m− 1) salinity stress. The correlation analysis confirmed a partial contribution of leaf area and seed vigour index to overall photosynthetic efficiency of white lupin.ConclusionsClearly, salinity exerted a negative impact on white lupin through a decline in chlorophyll content, activity of antioxidant enzymes and efficiency of photosynthetic apparatus. However, PGRs, especially ascorbic acid and potassium chloride considerably improved white lupin growth and development by mitigating the negative effects of salinity stress.

Have We Selected for Higher Mesophyll Conductance in Domesticating Soybean?

Soybean (Glycine max) is the single most important global source of vegetable protein. Yield improvements per unit land area are needed to avoid further expansion onto natural systems. Mesophyll conductance (gm) quantifies the ease with which CO2 can diffuse from the sub-stomatal cavity to Rubisco. Increasing gm is attractive since it increases photosynthesis without increasing water use. Most measurements of gm have been made during steady-state light saturated photosynthesis. In field crop canopies, light fluctuations are frequent and the speed with which gm can increase following shade to sun transitions affects crop carbon gain. Is there variability in gm within soybean germplasm? If so, indirect selection may have indirectly increased gm during domestication and subsequent breeding for sustainability and yield. A modern elite cultivar (LD11) was compared with four ancestor accessions of Glycine soja from the assumed area of domestication by concurrent measurements of gas exchange and carbon isotope discrimination (∆13C). gm was a significant limitation to soybean photosynthesis both at steady state and through light induction but was twice the value of the ancestors in LD11. This corresponded to a substantial increase in leaf photosynthetic CO2 uptake and water use efficiency.

γ-Aminobutyric Acid Alleviates Salinity-Induced Impairments in Rice Plants by Improving Photosynthesis and Upregulating Osmoprotectants and Antioxidants

Salt stress is a significant abiotic stress that hinders the growth of rice (Oryza sativa L.) and reduces their yield. Previous research has examined the synthesis of γ-aminobutyric acid (GABA) and its role in plant resistance under various abiotic stresses. However, the synthesis of GABA and its ability to mitigate damage caused by salt stress—particularly its effects on osmotic adjustment, antioxidant defense, photosynthesis, and overall plant growth throughout the entire rice lifecycle—remains unclear. Therefore, we conducted two experiments using salt-tolerant rice cultivar Lianjian 5 (J-5) and salt-susceptible cultivar Lianjing 7 (L-7). In Experiment I, RNA-seq (RNA sequencing) was used to analyze the differential expression of the transcriptome between CK and salinity treatments, revealing the key roles of GABA in salt tolerance. In Experiment II, different levels of exogenous GABA were applied to salt-stressed plants to investigate its physiological role in enhancing salt tolerance. Therefore, RNA-seq (RNA sequencing) was used to analyze the differential expression of the transcriptome between CK and salinity treatments, revealing the key roles of GABA in salt tolerance. Subsequently, different levels of exogenous GABA were applied to salt-stressed plants to investigate its physiological role in enhancing salt tolerance. We measured the activities of superoxide dismutase, peroxidase, and catalase, as well as photosynthetic characteristics such as photosynthesis, transpiration, chlorophyll content, stomatal density and size, and leaf anatomical features. The RNA-seq analysis revealed that GABA production is enhanced via the glutamate decarboxylase (GAD) gene (LOC4333932) in the salt-resistant rice cultivar. Exogenous GABA application improves salt-stress tolerance by increasing endogenous ABA and GABA contents, which enhance osmotic adjustment, boost antioxidant defenses, and regulate ion balance. These combined effects help maintain photosynthetic efficiency and support overall plant growth under salt-stressed environments. Additionally, the increased proportion of mesophyll cell periphery covered by chloroplasts (Sc/Sm) indicated enhanced mesophyll conductance. These helped maintain photosynthesis under saline conditions while reducing water consumption.

Green approaches for the synthesis of silver nanoparticle and its augmentation in Seed. germination, growth, and antioxidant level in Capsicum annuum L.

Eco-friendly natural nano-compounds, including biological extracts from Aspergillus niger, Azadirachta indica, and Moringa oleifera are known for their efficacy. Silver nanoparticles (AgNPs) improve seed germination, plant growth, and photosynthetic efficiency. This study focuses on how bio-silver may affect the development and physiology of Capsicum annuum L., specifically bio-silver nano priming with different quantities of synthesised nanoparticles. Nano priming improved seed germination (90–100 %), seedling length (53 %), seedling weight (75 %), seedling vigour index (65 %), as well as germination speed and index. The phytochemicals significantly increased chlorophyll (6–145 %), carotenoids (19–138 %), TPC (12–74 %), and TFC (7–80 %), all of which support plant growth. Nano priming also enhanced TAA (7–67 %) and FRAP (7–57 %). The total protein content (18–111 %) increased, promoting enzyme activity and plant development. Nano-priming increased ROS generation in seedlings more than the control and other priming treatments. This indicates that both ROS, including SOD (2–36 %) and POD (2–72 %), play crucial roles in seedling growth. The various mechanisms involved in nano priming-induced ROS/antioxidant systems in seedlings, such as the production of proline content (7–154 %) and the decrease in MDA (1–15 %), all contribute to the regulation of nanoparticle-generated stress.

Co-culture systems of microalgae and heterotrophic microorganisms: applications in bioproduction and wastewater treatment and elucidation of mutualistic interactions.

In recent years, reducing the concentration of carbon dioxide in the atmosphere has become an important issue. Microalgae have a higher photosynthetic efficiency and growth rate than higher plants; thus, biological carbon dioxide fixation using microalgae is attracting particular attention as an efficient carbon dioxide fixation method. However, under dilute atmospheric conditions, microalgae exhibit lower growth rates and reduced carbon dioxide fixation efficiency. In recent years, technology that can efficiently fix carbon dioxide, even in the atmosphere, using a microalgae co-culture system that co-cultivates microalgae and heterotrophic microorganisms has attracted attention. In such a co-culture system, it is believed that a mutualistic relationship is established between microorganisms through the exchange of various compounds. This review focuses on the application of a co-culture system of microalgae and heterotrophic microorganisms for bioproduction and wastewater treatment. In addition, research to elucidate the mutualistic relationships in microalgal co-culture systems using analytical methods that have been widely used in recent years, such as next-generation sequencing technology, is also discussed. In the future, it is expected that the use of microalgae co-culture systems will expand on an industrial scale through the development of key technologies, such as efficient genetic modification techniques for microalgae and their heterotrophic microorganism partners, large-scale cultivation facilities that can efficiently cultivate microalgae, and stable control techniques for co-culture systems using advanced technology.

Functions of exogenous strigolactone application and strigolactone biosynthesis genes GhMAX3/GhMAX4b in response to drought tolerance in cotton (Gossypium hirsutum L.)

BackgroundDrought stress markedly constrains plant growth and diminishes crop productivity. Strigolactones (SLs) exert a beneficial influence on plant resilience to drought conditions. Nevertheless, the specific function of SLs in modulating cotton’s response to drought stress remains to be elucidated.ResultsIn this study, we assess the impact of exogenous SL (rac-GR24) administration at various concentrations (0, 1, 5, 10, 20 µM) on cotton growth during drought stress. The findings reveal that cotton seedlings treated with 5 µM exogenous SL exhibit optimal mitigation of growth suppression induced by drought stress. Treatment with 5 µM exogenous SL under drought stress conditions enhances drought tolerance in cotton seedlings by augmenting photosynthetic efficiency, facilitating stomatal closure, diminishing reactive oxygen species (ROS) generation, alleviating membrane lipid peroxidation, enhancing the activity of antioxidant enzymes, elevating the levels of osmoregulatory compounds, and upregulating the expression of drought-responsive genes. The suppression of cotton SL biosynthesis genes, MORE AXILLARY GROWTH 3 (GhMAX3) and GhMAX4b, impairs the drought tolerance of cotton. Conversely, overexpression of GhMAX3 and GhMAX4b in respective Arabidopsis mutants ameliorates the drought-sensitive phenotype in these mutants.ConclusionThese observations underscore that SLs significantly bolster cotton’s resistance to drought stress.

Leaf nutrient basis for the differentiation of photosynthetic traits between subtropical evergreen and deciduous trees.

Compared to evergreens, deciduous tree species usually have higher photosynthetic efficiency to complete vegetative and reproductive growth in a shorter growing season. However, the nutrient basis for the differentiation of photosynthesis functional traits between evergreen and deciduous tree species has not yet been clarified. Thirty evergreen and twenty deciduous angiosperm tree species from a subtropical common garden were compared in terms of photosynthetic traits and leaf nutrients. Generally, their differences in area-based photosynthetic capacity were uncorrelated with area-based leaf nutrient content but were caused by the fraction of nitrogen allocated to photosynthetic components. By comparison, the differences in mass-based photosynthetic capacity were more correlated with leaf nitrogen content than leaf phosphorus and potassium content. Convergence in phosphorus and potassium constraints to photosynthesis occurred in deciduous tree species but not in evergreen tree species. Furthermore, leaf C/N ratio played a more significant role than leaf mass per area in determining the differentiation of photosynthetic traits between evergreen and deciduous groups. Our findings provide insight into the nutrient basis for photosynthetic carbon gain and functional strategies across trees species.

Heredity and fine mapping of a yellow leaf and less tillering mutant yllt10 in rice

Rice (Oryza sativa L.) is a major food crop and increasing rice yield is the primary objective of rice research. Photosynthesis and nitrogen utilization efficiency directly affect the tiller number of rice, which affects the yield of rice. In this study, a stable yellow leaf and less tillering rice mutant yllt10 (yellow leaf and less tillering 10) was obtained by heavy-ion beam mutagenesis of rice variety 'Ke-fu-geng 7'. Compared with the wild type, yllt10 showed reduced chlorophyll content, decreased photosynthesis rate, and abnormal chloroplast structure. The genetic analysis indicated that the phenotype of yllt10 was controlled by a single recessive nuclear gene. Map-based cloning localized YLLT10 between two molecular markers J4 and J5 on chromosome 10. The sequencing of candidate genes within this interval revealed that YLLT10 was an allelic mutation of CAO1/PGL with a single base deletion in the first exon resulting in the frame shift mutation of CAO1/PGL, and YLLT10 was a new allelic variation of CAO1/PGL. The mutant yllt10 was insensitive to changes in nitrogen concentration when being incubated with different nitrogen concentrations. YLLT10 controls leaf color and tiller number and affects photosynthesis and yield of rice. The study of this gene provides a theoretical basis for molecular breeding of rice.

Integrating Biofertilizers with Organic Fertilizers Enhances Photosynthetic Efficiency and Upregulates Chlorophyll-Related Gene Expression in Rice

Biofertilizers offer a sustainable method for improving rice growth and productivity, yet their effects on the interaction between plant growth, photosynthetic activity, and gene expression remain under-researched. This study examines how biofertilizer influences rice physiology, focusing on photosynthetic regulation and expression of chlorophyll-related genes. Eight fertilizer treatments were applied: control (CNT), biofertilizer (BF), deactivated biofertilizer (DABF), rice straw (RS), rice straw with biofertilizer (RS+BF), organic fertilizer (OF), organic fertilizer with biofertilizer (OF+BF), and inorganic fertilizer (IOF). Plant height, tiller number, SPAD, NDVI, chlorophyll content, and photosynthesis rates were measured, while gene expression analysis was conducted using RT-qPCR. The OF+BF treatment produced the most significant results, leading to a 31% increase in plant height, a 135% increase in tiller number, and a 42% increase in chlorophyll content (SPAD values) compared to the control. Additionally, OF+BF enhanced photosynthetic efficiency by 74%, with the highest net photosynthetic rate of 48.23 μmol CO2 m−2 s−1. Gene expression analysis revealed that OF+BF upregulated key photosynthesis-related genes, such as OsChlD and OsCHLM, showing a 70% and 90% increase in expression. These findings highlight the potential of integrating biofertilizers with organic fertilizers to sustainably boost rice growth and productivity, contributing to global food security and climate change mitigation.

A CC-Type Glutaredoxins GRX480 Functions in Cadmium Tolerance by Maintaining Redox Homeostasis in Arabidopsis

Cadmium (Cd) toxicity causes oxidative stress damage in plant cells. Glutaredoxins (GRXs), a type of small oxidoreductase, play a crucial role in modulating thiol redox states. However, whether GRXs act in Cd stress remains to be identified. Here, we reveal that Arabidopsis GRX480, a member of the CC-type family, enhances plant Cd stress tolerance. The GRX480 mutants exhibit enhanced sensitivity to Cd stress, manifested by shortened root, reduced biomass, lower chlorophyll and proline levels, and decreased photosynthetic efficiency compared with the wild type. The Cd concentration in GRX480 mutants is higher than the wild type, resulting from the inhibition of Cd efflux and transport genes transcription. Lower levels of GSH were detected in Cd-treated GRX480 mutants than in the wild type, indicating that GRX480 regulates plant Cd tolerance by influencing the balance between GSH and GSSG. Furthermore, the hyperaccumulation of reactive oxygen species (ROS) is associated with decreased expression of H2O2 scavenging genes in Cd-treated GRX480 mutants. Additionally, more toxic reactive carbonyl species (RCS), produced during oxidative stress, accumulate in Cd-treated GRX480 mutants than in wild type. Overall, our study establishes a critical role of GRX480 in response to Cd stress, highlighting its multifaceted contributions to detoxification and the maintenance of redox homeostasis.

Biochar influences phytoremediation of heavy metals in contaminated soils: an overview and perspectives.

Heavy metals (HMs) contamination has gained much attention due to its high degree of toxicity for living organisms. Therefore, different techniques are underway to eradicate HMs from the environment. Among the biological techniques, phytoremediation is a suitable method, but owing to the slow rate and chance of HMs penetration into the food chain, alternative techniques are needed to reduce their phytotoxicity, and biochar is one of them. Due to the diverse characteristics, biochar immobilizes HMs in the soil by improving soil pH, ion exchange, electrostatic interactions, complexation, precipitation, surface adsorption, and microbial activation. Thereby, amendment of biochar in the HMs-contaminated soils reduces HMs toxicity to plants and limits their penetration into the food chain. In contrast, some biochars have also been studied to induce metal availability in soils and subsequently its uptake by plants. This dual role of biochar depends on the feedstock of biochar, incineration temperature, and the rate of application. Moreover, biochar treatments enhance plant growth under HMs stress by improving nutrient availability, water retention capacity, scavenging of reactive oxygen species, and photosynthetic efficiency. Owing to the beneficial characteristics of biochar in HMs-contaminated sites, the number of publications has tremendously increased. Additionally, the plant species and the types of HMs that have been tested frequently under biochar treatments in these articles have been studied. Overall, the current study would help in understanding the mechanisms of how biochar influences phytoremediation of HMs and improves plant growth in HMs-polluted soils and the current scenario of the available literature.

Unleashing the Potential of CRISPR/Cas9 Genome Editing for Yield-Related Traits in Rice

Strategies to enhance rice productivity in response to global demand have been the paramount focus of breeders worldwide. Multiple factors, including agronomical traits such as plant architecture and grain formation and physiological traits such as photosynthetic efficiency and NUE (nitrogen use efficiency), as well as factors such as phytohormone perception and homeostasis and transcriptional regulation, indirectly influence rice grain yield. Advances in genetic analysis methodologies and functional genomics, numerous genes, QTLs (Quantitative Trait Loci), and SNPs (Single-Nucleotide Polymorphisms), linked to yield traits, have been identified and analyzed in rice. Genome editing allows for the targeted modification of identified genes to create novel mutations in rice, avoiding the unintended mutations often caused by random mutagenesis. Genome editing technologies, notably the CRISPR/Cas9 system, present a promising tool to generate precise and rapid modifications in the plant genome. Advancements in CRISPR have further enabled researchers to modify a larger number of genes with higher efficiency. This paper reviews recent research on genome editing of yield-related genes in rice, discusses available gene editing tools, and highlights their potential to expedite rice breeding programs.

Na+-driven pH regulation by Na+/H+ antiporters promotes photosynthetic efficiency in cyanobacteria.

Photosynthetic organisms have developed mechanisms to regulate light reactions in response to varying light conditions. Photosynthetic electron transport leads to the formation of a ΔpH across the thylakoid membrane, which is crucial for regulating electron transport. However, other pH modulators remain to be identified, particularly in cyanobacteria. In this study, we evaluated the potential involvement of six Na+/H+ antiporters (NhaS1-NhaS6) in control of pH in the cyanobacterium Synechocystis sp. PCC 6803. Synechocystis showed a strong requirement for Na+ at high light intensities, with ΔnhaS1 and ΔnhaS2 strains unable to grow under high light conditions. We analyzed Na+ efflux-driven H+-uptake activities of NhaS1-NhaS6 in inverted membranes of Escherichia coli. Biological fractionation and immunoelectron microscopy revealed that NhaS1 localizes to both the plasma and thylakoid membranes while NhaS2 localizes to the plasma membrane. Measurement of photosynthesis activity indicated that NhaS2 promotes ATP production and electron transport from PQ to P700. Measurements of pH outside of the cells and in the cytoplasm suggested that both NhaS1 and NhaS2 are involved in plasma membrane-mediated light-dependent H+ uptake and cytoplasmic acidification. NhaS1 and NhaS2 were also found to prevent photoinhibition under high light treatment. These results indicate that H+ transport mediated by NhaS1 and NhaS2 plays a role in regulating intracellular pH and maintaining photosynthetic electron transport.

Expanding the Triangle of U: Comparative analysis of the Hirschfeldia incana genome provides insights into chromosomal evolution, phylogenomics and high photosynthesis-related traits.

The Brassiceae tribe encompasses many economically important crops and exhibits high intraspecific and interspecific phenotypic variation. After a shared whole-genome triplication (WGT) event (Br-α, ~15.9 million years ago), differential lineage diversification and genomic changes contributed to an array of divergence in morphology, biochemistry, and physiology underlying photosynthesis-related traits. Here, the C3 species Hirschfeldia incana is studied as it displays high photosynthetic rates under high-light conditions. Our aim was to elucidate the evolution that gave rise to the genome of H. incana and its high-photosynthesis traits. We reconstructed a chromosome-level genome assembly for H. incana (Nijmegen, v2.0) using nanopore and chromosome conformation capture (Hi-C) technologies, with 409Mb in size and an N50 of 52Mb (a 10× improvement over the previously published scaffold-level v1.0 assembly). The updated assembly and annotation was subsequently employed to investigate the WGT history of H. incana in a comparative phylogenomic framework from the Brassiceae ancestral genomic blocks and related diploidized crops. Hirschfeldia incana (x=7) shares extensive genome collinearity with Raphanus sativus (x=9). These two species share some commonalities with Brassica rapa and B. oleracea (A genome, x=10 and C genome, x=9, respectively) and other similarities with B. nigra (B genome, x=8). Phylogenetic analysis revealed that H. incana and R. sativus form a monophyletic clade in between the Brassica A/C and B genomes. We postulate that H. incana and R. sativus genomes are results of hybridization or introgression of the Brassica A/C and B genome types. Our results might explain the discrepancy observed in published studies regarding phylogenetic placement of H. incana and R. sativus in relation to the "Triangle of U" species. Expression analysis of WGT retained gene copies revealed sub-genome expression divergence, likely due to neo- or sub-functionalization. Finally, we highlighted genes associated with physio-biochemical-anatomical adaptive changes observed in H. incana which likely facilitate its high-photosynthesis traits under high light. The improved H. incana genome assembly, annotation and results presented in this work will be a valuable resource for future research to unravel the genetic basis of its ability to maintain a high photosynthetic efficiency in high-light conditions and thereby improve photosynthesis for enhanced agricultural production.

Morphological Characterization-based Optimal Trait Selection for Improving Yield and Stability of Soybean (Glycine max L. Merrill)

The present investigation was convened during kharif, 2022 (July–October), rabi-Summer 2023 (January–May) and kharif, 2023 (July–October) at J.N.K.V.V., Jabalpur, Madhya Pradesh, India to characterize 165 diverse soybean germplasm lines in pursuance of DUS (Distinctness, Uniformity, and Stability) guidelines focusing on integrating optimal morphological traits to pre-fine soybean crop improvement. The study revealed significant variation among soybean genotypes. The hypocotyl color, controlled by a monogenic trait, was found in 77 genotypes, closely associated with violet flower color, whereas non-pigmented hypocotyls present in 88 genotypes were linked to white flowers. Growth habits were categorized as determinate (59), semi-determinate (103), and indeterminate (3), demonstrating that semi-determinate genotypes offer balanced resource allocation and reduced lodging. Most genotypes displayed medium flowering time (159) and medium plant height (134). Leaf shape was predominantly pointed ovate (121), with lanceolate leaves associated with higher number of seeds-1 pod. The presence of dark green leaves in 108 genotypes indicated higher chlorophyll content and enhanced photosynthetic efficiency to strengthen plant type. Semi-erect growth habit was prevalent in 152 genotypes, providing better soil coverage and moisture retention, while 13 genotypes showed erect growth. Pod pubescence was observed in 106 genotypes, offering protection against pests. These traits are found stable across the environment and may be used as an identification key for different varieties and donor germplasm lines.

Comparative study of the photosynthetic efficiency and leaf structure of four Cotoneaster species

Plants belonging to the genus Cotoneaster can be valuable sources of phytochemicals with potential therapeutic properties. The natural habitats of most of these species are situated in Asia, Africa and southern Europe. Introducing them into other climatic conditions could expose them to abiotic and biotic stresses, affecting their bioactive properties. The aim of this study was to assess and compare the performance of four non-native Cotoneaster species (C. roseus, C. hissaricus, C. hsingshangensis, C. nebrodensis) grown in eastern Poland in terms of leaf morphology, anatomy, and efficiency of the photosynthetic apparatus in relation to lipid peroxidation level, being an indicator of oxidative stress. Photosynthetic pigments concentration and chlorophyll a fluorescence parameters were used to evaluate the photosynthetic capacity. The morphological and anatomical analysis of leaves did not show any anomalies or stress symptoms. Cotoneaster roseus was characterized by the highest chlorophyll concentration, viability index (Rfd) and a moderate lipid peroxidation level. On the other hand, the lowest values of photochemical quenching (qP), maximum fluorescence (Fm), Rfd, and quantum yield of the photosystem II (QY) observed for C. nebrodensis might indicate an inferior efficiency of the photosynthetic apparatus in this species; however, it demonstrated the lowest lipid peroxidation level. Nevertheless, the content and proportion of the photosynthetic pigments as well as overall chlorophyll a fluorescence parameters and lipid peroxidation levels indicate a good physiological condition of all examined plants. The observed differences between the species may be rather species specific and genetically established and not indicate their sensitivity to non-native growth conditions. This is the first report about the physiological parameters of the four Cotoneaster species, proving they are well adapted to growth in the climatic conditions of central Europe providing thus a raw material with potential for pharmaceutical applications.

Effects of foliar application of two forms of selenium on anatomic features of Thymus daenensis Celak

To investigate selenium effects on anatomic features of Thymus daenensis, three concentrations of bulk and nanoparticles of the element (2, 4 and 8 ppm) along with distilled water, as a control, were sprayed on foliar of young seedlings of the plant species for six times with 2 weeks intervals. Transverse sections of stems, roots and leaves of the treated plants were manually produced and stained by Carmine and Methylene blue. Average of 5 readings was recorded for each treatment on several anatomic traits. Statistical analysis of the data revealed that the effects of selenium treatments were significantly different, at 1% of probability, on all of the studied anatomic characters. The first level of nanoparticles showed the most positive effects on several root characteristics. The highest level of selenium nanoparticles (8 ppm) showed the most positive effects on stem diameter and stem vascular cylinder diameter. The last two levels of nanoparticles had similar and the largest effect on stem epidermis thickness. The lowest level of bulk selenium (2 ppm) showed the most increment on leaf characteristics. Application of a low concentration of selenium by foliar spraying on young plants of the species is suggested for more vegetative growth and higher photosynthetic efficiency

Choline chloride and N-allylglycine promote plant growth by increasing the efficiency of photosynthesis.

We previously reported that choline chloride and N-allylglycine stimulate photosynthesis in wheat protoplasts. Treatment of Arabidopsis thaliana and Brassica rapa plants with both compounds promoted growth and photosynthesis. To clarify the relationship between the enhancement of photosynthesis and increased growth, A. thaliana T87 cells, which show photosynthesis-dependent growth, and YG1 cells, which use sugar in the medium for growth, were treated with choline chloride or N-allylglycine. Only the T87 cells showed increased growth, suggesting that choline chloride and N-allylglycine promote growth by increasing photosynthetic activity. Transcriptome analysis using choline chloride and N-allylglycine-treated plants showed that the most abundant transcripts corresponded to photosynthetic electron transfer-related genes among the genes upregulated by both compounds. Furthermore, the compounds also upregulated genes encoding transcription factors that may control the expression of these photosynthetic genes. These results suggest that choline chloride and N-allylglycine promote photosynthesis through increased expression of photosynthetic electron transfer-related genes.