Growth Of Seedlings Research Articles

Exploring Polybag Size, Nursery Mixtures and Rootstocks for Optimizing Lasoda (Cordia myxa L.) Nursery Techniques

Background: Lasoda (Cordia myxa L.) is lesser utilized fruit plant species suitable for growing in large parts of arid and semi-arid regions of India. Besides the economic importance of its fruits in the vegetable and pickle industry, this species is also known for ethnomedicinal properties in different plant parts. In order to utilize it to its fullest potential, standardization of nursery technology for mass multiplication by vegetative propagation method is a necessary step. With the above background in the view, an experiment was conducted to see the effect of polybag size, nursery mixture and rootstock on seed germination, growth of seedlings after germination, budding success and growth of budded plants. Methods: The study was conducted during June-September, 2020. The treatment comprised of two polybag sizes, six nursery media compositions and two kinds of rootstocks. The observations were recorded on seed germination, seedling growth, days to bud sprout after budding, budding success and shoot length and diameter after 30 days of budding. Result: The main effects of nursery mixture revealed that plant height, stem diameter, number of leaves, shoot length and shoot diameter after budding were significantly affected by nursery mixture composition. The highest plant height (29.53 cm) recorded in the M4 mixture was significantly higher over M1, M2 and M3 but the differences were non-significant when compared with M5 and M6. A similar trend was also recorded in the case of stem diameter and number of leaves which showed significantly higher values in M4, M5 and M6 as compared to M1, M2 and M3. The highest shoot length (8.34 cm) and shoot diameter (3.40 mm) were recorded in M5 and M4 which were significantly higher than most of other media levels.

Impact of various microplastics on the morphological characteristics and nutrition of the young generation of beech (Fagus sylvatica L.)

Microplastics have the capacity to accumulate in soil due to their high resistance to degradation, consequently altering soil properties and influencing plant growth. This study focused on assessing the impact of various types and doses of microplastics on beech seedling growth. In our experiment, we used polypropylene and styrene granules with diameter of 4.0 mm in quantities of 2.5% and 7%. The hypothesis was that microplastics significantly affect seedlings' nutritional status and growth characteristics. The research analysed seedlings' nutrition, root morphological features, above-ground growth, and enzymatic activity in the substrate. Results confirmed the importance of microplastics in shaping the nutritional status of young beech trees. Microplastic type significantly impacted N/P and Ca/Mg stoichiometry, while microplastic quantity influenced Ca/Al and Ca+K+Mg/Al stoichiometry. Notably, only in the case of root diameter were significantly thicker roots noted in the control variant, whereas microplastics played a role in shaping the leaves' characteristics of the species studied. The leaf area was significantly larger in the control variant compared to the variant with polypropylene in the amount of 2.5% and styrene in the amount of 7%. Additionally, the study indicates a significant impact of microplastics on enzyme activity. In the case of CB and SP, the activity was twice as high in the control variant compared to the variants with microplastics. In the case of BG, the activity in the control variant was higher in relation to the variants used in the experiment. Research on the impact of microplastics on the growth of beech seedlings is crucial for enhancing our understanding of the effects of environmental pollution on forest ecosystems. Such studies are integral in shaping forestry management practices and fostering a broader public understanding of the ecological implications of plastic pollution.

A novel growth-promoting dark septate endophytic fungus improved drought tolerance in blueberries by modulating phytohormones and non-structural carbohydrates.

Drought is a significant global issue affecting agricultural production, and the utilization of beneficial rhizosphere microorganisms is one of the effective ways to increase the productivity of crops and forest under drought. In this study, we characterized a novel growth-promoting dark septate endophytes (DSE) fungus R16 derived from the blueberry roots. Hyphae or microsclerotia were visible within the epidermal or cortical cells of R16-colonized blueberry roots, which was consistent with the typical characteristics of DSE fungi. Inoculation with R16 promoted the growth of blueberry seedlings and the advantage over the control group was more significant under PEG-induced drought. Comparison of physiological indicators related to drought resistance between the inoculated and control groups was performed on the potted blueberry plants, including the chlorophyll content, net photosynthetic rate, root activities, MDA and H2O2 content, which indicated that R16 colonization mitigated drought injury in blueberry plants. We further analyzed the effects of R16 on phytohormones and non-structural carbohydrates (NSCs) to explore the mechanism of increased drought tolerance by R16 in blueberry seedlings. The results showed that except for the GA content, IAA, ZT and ABA varied significantly between the inoculated and control groups. SPS and S6PDH activities in mature leaves, the key enzymes responsible for sucrose and sorbitol synthesis, respectively, as well as SDH, SuSy, CWINV, HXK and FRK in roots, the key enzymes involved in the NSCs metabolism, showed significant differences between the inoculated and control groups before and after drought treatment. These results suggested that the positive effects of R16 colonization on the drought tolerance of blueberry seedlings are partially attributable to the regulation of phytohormone and sugar metabolism. This study provided valuable information for the research on the interaction between DSE fungi and host plants as well as the application of DSE preparations in agriculture.

Impacts of Downed Dead Wood Poplar Trees on Forest Regeneration in the Semi-Arid Region of Northern China

In the past few decades, due to rising temperatures and changes in precipitation, the degree of drought in semi-arid areas has increased, leading to a large number of tree deaths and threatening the natural forests distributed in the semi-arid areas of North China. This article takes the forest ecosystem of Saihanwula Nature Reserve in the southern section of Greater Khingan Mountains in China’s semi-arid region as a research area and studies the distribution of downed dead wood and its impact on forest renewal in the area. We used the sample plot survey method, investigated the number of downed dead wood, decay class, dumping direction, existence form, and the number of regenerated seedlings in the sample plot, and calculated the density of regenerated seedlings in different plots. The renewal density is 4050 ± 824, 2950 ± 265, plants/ha, and 2625 ± 237 plants/ha, respectively, in the sample plots for Later-death plot, Mid-death plot, and Early-death plot. The average storage of downed dead wood in Saihanwula Nature Reserve is 58.51 ± 16.56 m3/ha. The distribution densities of downed dead wood are 50 ± 21, 806 ± 198, 189 ± 76, and 22 ± 5 plants/ha for decay classes II, III, IV, and V respectively. The main form of downed dead wood in the research area is “trunk base fracture”, accounting for 68.78% of the total number of downed dead wood. A large number of downed dead wood had serious negative effects, such as crushing and injuring the regeneration seedlings and other plants under the forest at the moment of dumping and for a long time after dumping. The crushed and injured rate is 5.3~7.8%, with downed dead wood accumulated in the forest from the early stage of downed dead wood. It had negative effects on the regeneration of seeds, seedlings, and young trees, such as obstructing and hiding the light from the soil surface and inhibiting the regeneration and growth of seedlings. However, after the trees were dumped, large gaps appeared in the forest, increasing the sunlight area on the soil surface. In the later stage of tree death, moderately high decayed downed dead wood changed the soil structure in terms of soil softness, water holding capacity, and nutrient content, thus promoting the growth of seedlings and young trees. Reasonably utilizing the relationship between downed dead wood and forest renewal can effectively promote the healthy development of forests.

Physiological, Metabolome and Gene Expression Analyses Reveal the Accumulation and Biosynthesis Pathways of Soluble Sugars and Amino Acids in Sweet Sorghum under Osmotic Stresses.

Water scarcity is a major environmental constraint on plant growth in arid regions. Soluble sugars and amino acids are essential osmolytes for plants to cope with osmotic stresses. Sweet sorghum is an important bioenergy crop and forage with strong adaptabilities to adverse environments; however, the accumulation pattern and biosynthesis basis of soluble sugars and amino acids in this species under osmotic stresses remain elusive. Here, we investigated the physiological responses of a sweet sorghum cultivar to PEG-induced osmotic stresses, analyzed differentially accumulated soluble sugars and amino acids after 20% PEG treatment using metabolome profiling, and identified key genes involved in the biosynthesis pathways of soluble sugars and amino acids using transcriptome sequencing. The results showed that the growth and photosynthesis of sweet sorghum seedlings were significantly inhibited by more than 20% PEG. After PEG treatments, the leaf osmotic adjustment ability was strengthened, while the contents of major inorganic osmolytes, including K+ and NO3-, remained stable. After 20% PEG treatment, a total of 119 and 188 differentially accumulated metabolites were identified in the stems and leaves, respectively, and the accumulations of soluble sugars such as raffinose, trehalose, glucose, sucrose, and melibiose, as well as amino acids such as proline, leucine, valine, serine, and arginine were significantly increased, suggesting that these metabolites should play key roles in osmotic adjustment of sweet sorghum. The transcriptome sequencing identified 1711 and 4978 DEGs in the stems, as well as 2061 and 6596 DEGs in the leaves after 20% PEG treatment for 6 and 48 h, respectively, among which the expressions of genes involved in biosynthesis pathways of sucrose (such as SUS1, SUS2, etc.), trehalose (including TPS6), raffinose (such as RAFS2 and GOLS2, etc.), proline (such as P5CS2 and P5CR), leucine and valine (including BCAT2), and arginine (such as ASS and ASL) were significantly upregulated. These genes should be responsible for the large accumulation of soluble sugars and amino acids under osmotic stresses. This study deepens our understanding of the important roles of individual soluble sugars and amino acids in the adaptation of sweet sorghum to water scarcity.

Use of biostimulants for water stress mitigation in two durum wheat (Triticum durum Desf.) genotypes with different drought tolerance

Agriculture is facing complex and unprecedented challenges, such as climate change and global population growth, associated with the increase of food demand. Durum wheat (DW) is a strategic crop for food security in the Mediterranean region. In this work, the effect of two biostimulant compounds on drought response of two DW genotypes with different drought tolerance degree was evaluated: the tolerant genotype Svems16 and the sensitive cv. Iride. Genotyping-By-Sequencing analysis allowed to identify variants in response to water-related genes, such as those encoding dehydrins, with Svems16 exhibiting a missense variant divergent from the sequence found in Iride. Drought significantly hindered growth of cv. Iride by increasing oxidative stress and diminishing stomata density. This difficulty was mitigated by the application of biostimulants, which induced root morphological changes, and increased stomata density. On the other hand, the growth of Svems16 seedlings was not significantly affected by drought, confirming its significant degree of tolerance toward that stress compared with Iride. As a result, both biostimulants showed limited efficacy when applied to Svems16 stressed plants. In conclusion, the application of biostimulants emerges as a valuable agronomic strategy for mitigating drought stress in sensitive DW cultivars.

Growth Response of Cocoa Seedlings (Theobroma cacao L.) in several Combinations of Planting Media and Trichoderma sp. as Biological Fertilizer

Indonesia is the third largest cocoa (Theobroma cacao L.) producing country in the world. In 2019 cocoa production in Lampung was 58,852 tons with a plantation area of 79,356 ha, in 2020 it was 58,623 tons with an area of 79,469 ha and in 2021 58,414 tons with an area of 77,174 ha. One of the reasons for this decline in production is plant pest organisms (OPT), namely fruit rot disease caused by the pathogen Pytophthora palmivora. Use of Trichoderma sp. can increase plant resistance and growth and act as a biological controller outside and inside the soil. The research was carried out on the grounds of the Lampung State Polytechnic from August to November 2023. This research aims to determine the effect of planting media and administration of Trichoderma sp. on the growth of cocoa seedlings. The method used was a Randomized Block Design (RAK) with 4 treatments and 4 replications so that there were 16 experimental units. Treatment P0 consisted of: Top Soil (Control), P1 Top Soil + Compost Fertilizer (2:1), P2 Top Soil + Trichoderma sp. (50:1), P3 Top Soil + Compost + Trichoderma sp. (50:25:1). The results of the research on treatments P3, P2 and P1 affected plant height, number of leaves and stem diameter. The P3 treatment showed the best results for the variables plant height 39.50 cm, number of leaves 21.58 and leaf area 37.79 cm2. Treatment P2 showed the best results for the stem diameter variable of 0.66 cm.

Strip Tillage Improves Productivity of Direct-Seeded Oilseed Rape (Brassica napus) in Rice–Oilseed Rape Rotation Systems

Oilseed rape (Brassica napus) is a crucial global oil crop. It is generally cultivated in rotation with rice in southern China’s Yangtze River Basin, where the wet soil and residue retention after rice harvest significantly hinder its seedling establishment. Hence, this study developed a strip-tillage seeder for oilseed rape seeding following rice harvest. Additionally, seedling establishment, soil infiltration and evaporation post-seeding, soil moisture change, oilseed yield, and weed occurrence under strip tillage (ST) were compared with conventional shallow rotary-tillage (SR) and deep rotary-tillage (DR) seeding practices. Compared to SR and DR, the results demonstrated that ST had a higher seeding efficiency and 53.8% and 80.2% lower energy consumption, respectively. ST also enhanced seedling growth and oilseed yield formation more effectively than the competitor tillage treatments, with an oilseed yield increase exceeding 6%. Additionally, ST improved water infiltration and reduced soil water evaporation, resulting in higher topsoil (0–20 cm) moisture during the critical growth stages. Furthermore, ST reduced soil disturbance, significantly decreasing the density of the dominant weed, Polypogon fugax. Overall, ST seeding technology has the potential to improve the productivity of oilseed rape in rice–oilseed rape rotation systems, and its yield superiority is mainly due to seedling establishment improvement and soil moisture adjustment.

Gβγ dimers mediate low K+ stress-inhibited root growth via modulating auxin redistribution in Arabidopsis.

In the investigation of heterotrimeric G protein-mediated signal transduction in planta, their roles in the transmittance of low K+ stimuli remain to be elucidated. Here, we found that the primary root growth of wild-type Arabidopsis was gradually inhibited with the decrease of external K+ concentrations, while the primary root of the mutants for G protein β subunit AGB1 and γ subunits AGG1, AGG2 and AGG3 could still grow under low K+ conditions (LK). Exogenous NAA application attenuated primary root elongation in agb1 and agg1/2/3 but promoted the growth in wild-type seedlings under LK stress. Using ProDR5:GFP, ProPIN1:PIN1-GFP and ProPIN2:PIN2-GFP reporter lines, a diminishment in auxin concentration at the radicle apex and a reduction in PIN1and PIN2 efflux carrier abundance were observed in wild-type roots under LK, a phenomenon not recorded in the agb1 and agg1/2/3. Further proteolytic and transcriptional assessments revealed an enhanced degradation of PIN1 and a suppressed expression of PIN2 in the wild-type background under LK, contrasting with the stability observed in the agb1 and agg1/2/3 mutants. Our results indicate that the G protein β and γ subunits play pivotal roles in suppressing of Arabidopsis root growth under LK by modulating auxin redistribution via alterations in PIN1 degradation and PIN2 biosynthesis.

Sustainable cottonseed protein bioplastics: Physical and chemical reinforcement, and plant seedling growth application

Petroleum-based plastic containers for plant seedling growth are expensive to recycle and have negative environmental impacts when discarded. In this work, a novel family of sustainable and biodegradable plastic films and containers were fabricated by simply casting and mold-curing methods, which demonstrated outstanding performance promoting crop seed germination and plant seedling growth. Concentrate cottonseed protein (CPC) was used as polymeric matrix, pulp fiber (PF) as a physical reinforcement, tannic acid (TA) as a chemical modifying agent, with their addition contents ranging from 0 ∼ 30 % (PF) and 0 ∼ 10 % (TA), respectively. Evaluations of the composite CPC/PF and CPC/TA films regarding their structure, morphology, tensile properties, and water resistance show that the physical and chemical reinforcement resulted in good interfacial compatibility, mechanical strength, and water resistance. Moreover, the newly prepared bioplastics were biodegradable in soil in three weeks, and did not harm crop seed germination and growth. More importantly, the protein derived biocontainers/pot (CPC/PF30 and CPC/TA10) can provide excellent growth conditions for plant root and leaf growth such as chili peppers because of their low toxicity and 100 % germination rate. More importantly, the healthy growing environment was closely related to the presence of nutritious elements/ions that the plant needed. Specifically, the biodegradation of the bioplastics during plant seedling test released nitrogen-containing ions like NH4+ (0.25 wt% for CPC/TA10 versus 0.17 wt% for polyethylene), and retained in soil, playing a decisive role in seedling growth. Therefore, the cottonseed protein bioplastics reinforced by pulp fiber and tannic acid are beneficial to crop seedling growth, holding great potential for being used as plantable pots/containers in agriculture and horticulture applications.

Evaluating the effect of plantlet age and Trichoderma spp. application on acclimatization of Boehmeria nivea L. Gaud

One of the crucial stages in the ramie plant (Boehmeria nivea L. Gaud) tissue culture is the acclimatization phase, which transitions between the in vitro and ex-vitro environments. Determining the appropriate age of plantlets and providing nutrients in the substrate play significant roles in the success of acclimatization. This research is conducted to determine the most suitable age of plantlets for acclimatization and assess the impact of providing nutrients through Trichoderma spp. application on the growth of ramie seedlings during the acclimatization phase. The experiment was conducted between January and March 2023 at the Screenhouse Bale Tatanen, Faculty of Agriculture, Universitas Padjadjaran, Jatinangor, Sumedang. The experimental design used was a Randomized Complete Block Design (RCBD) with two factors: plantlet age with three levels (4, 8, and 12 weeks old) and Trichoderma spp. fertilizer application with two levels (without and with Trichoderma) with 4 replications. The results showed that the 4-week-old plantlets exhibited the best height, root number, root length, and leaf number growth. Additionally, the application of Trichoderma spp. increased the stem diameter of the ramie seedlings during the acclimatization phase.

Changes in decomposition dynamics, soil community function and the growth of native seedlings under the leaf litter of two invasive plants

Changes in decomposition dynamics, soil community function and the growth of native seedlings under the leaf litter of two invasive plants

Recovery of Scots Pine Seedlings from Long-Term Zinc Toxicity.

We studied the recovery of the growth and physiological parameters of Scots pine seedlings after long-term zinc toxicity. The removal of excess zinc from the nutrient solution resulted in the rapid recovery of primary root growth but did not promote the initiation and growth of lateral roots. The recovery of root growth was accompanied by the rapid uptake of manganese, magnesium, and copper. Despite the maximum rate of manganese uptake by the roots, the manganese content in the needles of the recovering plants did not reach control values during the 28 days of the experiment, unlike magnesium, iron, and copper. In general, the recovery of ion homeostasis eliminated all of the negative effects on the photosynthetic pigment content in the needles. However, these changes, along with recovery of the water content in the needles, were not accompanied by an increase in the weight gain of the recovering seedlings compared with that of the Zn-stressed seedlings. The increased accumulation of phenolic compounds in the needles persisted for a long period after excess zinc was removed from the nutrient solution. The decreased lignin content in the roots and needles is a characteristic feature of Zn-stressed plants. Moreover, the removal of excess zinc from the nutrient solution did not lead to an increase in the lignin content in the organs.

Seed Germination and Subsequent Seedling Growth as Influenced by Silica Nanoparticles Invigoration in Soybean (Glycine max (L.) Merrill.)

Seed Germination and Subsequent Seedling Growth as Influenced by Silica Nanoparticles Invigoration in Soybean (Glycine max (L.) Merrill.)

The Impact of Lighting Treatments on the Biosynthesis of Phenolic Acids in Black Wheat Seedlings.

Light, as a crucial environmental determinant, profoundly influences the synthesis of secondary metabolites in plant metabolism. This study investigated the impacts of the red light combined with ultraviolet-A (UV-A) and ultraviolet-B (UV-B) treatments on phenolic acid biosynthesis in black wheat seedlings. The results demonstrate that the red light combined with UV-A and UV-B treatments significantly enhanced the levels of phenolic acids in black wheat seedlings, at 220.4 μg/seedling and 241.5 μg/seedling, respectively. The content of bound phenolic acids in black wheat seedlings increased by 36.0% under the UV-B treatment. The application of the UV-A/UV-B treatments markedly enhanced the activities of phenylalanine ammonia-lyase, 4-coumarate CoA ligase, and cinnamate 4-hydroxylase in black wheat seedlings while also promoting the expression levels of genes related to phenolic acid synthesis. The expression levels of fructose-1,6-bisphosphate aldolase and NADP-malic enzyme related to photosynthesis were significantly upregulated. This resulted in an augmentation in the chlorophyll content, thereby enhancing photosynthesis in black wheat seedlings. Nevertheless, the UV-A and UV-B treatments also had a significant constraining effect on the growth and development of black wheat seedlings. In addition, the UV-A and UV-B treatments increased the activity and gene expression levels of antioxidant enzymes while significantly increasing the contents of total flavonoids and anthocyanins, activating the antioxidant system. The findings reveal that light-source radiation serves as an effective method for promoting the biosynthesis of phenolic acids in black wheat seedlings.

The Effect of 24–Epibrassinolide on vegetative growth of Sweet Ann strawberry seedling under lime stress conditions

The Effect of 24–Epibrassinolide on vegetative growth of Sweet Ann strawberry seedling under lime stress conditions

Characteristics of biofilms on polylactic acid microplastics and their inhibitory effects on the growth of rice seedlings: A comparative study of petroleum-based microplastics

Increasing evidence highlights the negative effects of microplastics (MPs) on crops and bio-based plastics offer an alternative to conventional plastics. However, there is limited knowledge on the impacts and mechanisms of bio-based MPs on crop physiology. In this study, bio-based polylactic acid (PLA) and petroleum-based MPs [polyamide (PA) and polypropylene (PP)] were added to hydroponic cultures planted with rice (Oryza sativa L.) seedlings to assess their toxicity. Compared to PA and PP MPs, PLA MPs experienced greater aging after 28 days of exposure, and their surfaces were loaded with more rod-shaped microorganisms with potential plastic degradation ability, such as Proteobacteria and Bacteroidota, which competed with rice seedlings for carbon and nitrogen sources for self-multiplication, thus altering the carbon fixation and nitrogen cycling processes during rice seedling growth. Down-regulation of amino acid and lipid metabolisms in the PLA treatment inhibited the normal synthesis of chlorophyll in rice seedling leaves. Consequently, decreases in the biomass and height of rice seedling roots and shoots were observed in the PLA MP treatment. This study provides evidence that bio-based MPs may have a more severe impact on crop growth than petroleum-based MPs.

Impacts of cyanobacteria-dominated biological soil crusts on seedling emergence and fate: an in situ experiment

Abstract Background and aims Biological soil crusts (BSCs) co-occur with vascular plants in many ecosystems. Nevertheless, little is known regarding the interaction among BSCs and vascular plants, and no standard methods exist aiming to evaluate BSC–plant interactions. While some reports emphasized the inhibition effect of BSCs on germination, others reported the opposite or did not find any differences between germination under crusted and non-crusted conditions. Contradictory findings were also reported regarding the BSC effects on vascular plants after germination, with some reports claiming that BSCs promote growth, while others claim the opposite. Methods By a seed addition experiment (using light and heavy seeds of three species belonging to the Fabaceae family) in an early-successional system in Germany, we tested in situ the emergence of seedlings under variable surface conditions (cyanobacterial crust, disturbed and removed crust), and quantified crust-plant interactions (survival, flowering) during and following seedling emergence. Results In comparison to an average of 8% of the light Lotus corniculatus and 20% of the light Ornithopus sativus that emerged through the cyanobacterial BSC, 76% of the heavy Glycine max emerged. Once emerged, the crust did not significantly affect the survival, growth, biomass, or flowering of G. max, whereas many of the seedlings from lightweight seeds dried up soon after emergence. The thickness of the cyanobacterial biocrust had no influence on Fabaceae emergence. Conclusion The cyanobacterial BSC acted as a filter that hindered the emergence of the lightweight seeds.

The ectomycorrhizal fungus Scleroderma bovista improves growth of hazelnut seedlings and plays a role in auxin signaling and transport.

Scleroderma bovista can form symbiotic ectomycorrhizal fungi with hazel roots. The mechanism through which S. bovista promotes hazelnut growth remains unclear. This study aimed to evaluate the effect of ectomycorrhizal fungus S. bovista on the growth and development of hazel roots and gene expression changes through comparative transcriptome analysis. After inoculation with S. bovista, the fungus symbiotically formed ectomycorrhiza with hazel roots. The fresh weights of the aboveground and underground parts of My treatment (inoculated with S. bovista and formed mycorrhiza) were much higher than those of the control, respectively. The length, project area, surface area, volume, forks, and diameter of the inoculated seedlings root were 1.13 to 2.48 times higher than those of the control. In the paired comparison, 3,265 upregulated and 1,916 downregulated genes were identified. The most significantly enriched Gene Ontology term for the upregulated Differentially Expressed Genes was GO:0005215 (transporter activity). Immunohistochemical analysis suggested that the expression levels of auxin and Auxin Response Factor9 were significantly increased by S. bovista after the formation of mycorrhizal fungi in hazelnut root tips. These results indicate that genes related to auxin biosynthesis, transport and signaling, and transport of nutrients may contribute to root development regulation in hazel ectomycorrhiza.

Transcriptomic and physiological responses of Quercus acutissima and Quercus palustris to drought stress and rewatering.

Establishment of oak seedlings, which is an important factor in forest restoration, is affected by drought that hampers the survival, growth, and development of seedlings. Therefore, it is necessary to understand how seedlings respond to and recover from water-shortage stress. We subjected seedlings of two oak species, Quercus acutissima and Quercus palustris, to drought stress for one month and then rewatered them for six days to observe physiological and genetic expression changes. Phenotypically, the growth of Q. acutissima was reduced and severe wilting and recovery failure were observed in Q. palustris after an increase in plant temperature. The two species differed in several physiological parameters during drought stress and recovery. Although the photosynthesis-related indicators did not change in Q. acutissima, they were decreased in Q. palustris. Moreover, during drought, content of soluble sugars was significantly increased in both species, but it recovered to original levels only in Q. acutissima. Malondialdehyde content increased in both the species during drought, but it did not recover in Q. palustris after rewatering. Among the antioxidant enzymes, only superoxide dismutase activity increased in Q. acutissima during drought, whereas activities of ascorbate peroxidase, catalase, and glutathione reductase increased in Q. palustris. Abscisic acid levels were increased and then maintained in Q. acutissima, but recovered to previous levels after rewatering in Q. palustris. RNA samples from the control, drought, recovery day 1, and recovery day 6 treatment groups were compared using transcriptome analysis. Q. acutissima exhibited 832 and 1076 differentially expressed genes (DEGs) related to drought response and recovery, respectively, whereas Q. palustris exhibited 3947 and 1587 DEGs, respectively under these conditions. Gene ontology enrichment of DEGs revealed "response to water," "apoplast," and "Protein self-association" to be common to both the species. However, in the heatmap analysis of genes related to sucrose and starch synthesis, glycolysis, antioxidants, and hormones, the two species exhibited very different transcriptome responses. Nevertheless, the levels of most DEGs returned to their pre-drought levels after rewatering. These results provide a basic foundation for understanding the physiological and genetic expression responses of oak seedlings to drought stress and recovery.