Search Results (811)

Cucumbers (Cucumis sativus L.) are highly sensitive to cold, but grafting onto cold-tolerant rootstocks can enhance their low-temperature resilience. This study investigates the physiological and molecular mechanisms by which exogenous vitamin C (Vc) mitigates cold stress in grafted cucumber seedlings. Using cucumber ‘Chiyu 505’ as the scion and pumpkin ‘Chuangfan No.1’ as the rootstock, seedlings were grafted using the whip grafting method. In the third true leaf expansion stage, seedlings were foliar sprayed with Vc at concentrations of 50, 100, 150, and 200 mg L⁻¹. Three days after initial spraying, seedlings were subjected to cold stress (8 °C) for 3 days, with continued spraying. After that, morphological and physiological parameters were assessed. Results showed that 150 mg L⁻¹ Vc treatment was most impactive, significantly reducing the cold damage index while increasing the root-to-shoot ratio, root vitality, chlorophyll content, and activities of antioxidant enzymes (SOD, POD, CAT). Moreover, this treatment enhanced levels of soluble sugars, soluble proteins, and proline compared to control. However, 200 mg L⁻¹ treatment elevated malondialdehyde (MDA) content, indicating potential oxidative stress. For transcriptomic analysis, leaves from the 150 mg L⁻¹ Vc and CK treatments were sampled at 0, 1, 2, and 3 days of cold stress. Differential gene expression revealed that genes associated with photosynthesis (LHCA1), stress signal transduction (MYC2-1, MYC2-2, WRKY22, WRKY2), and antioxidant defense (SOD-1, SOD-2) were initially up-regulated and subsequently down-regulated, as validated by qRT-PCR. Overall, we found that the application of 150 mg L⁻¹ Vc enhanced cold tolerance in grafted cucumber seedlings by modulating gene expression networks related to photosynthesis, stress response, and the antioxidant defense system. This study provides a way for developing Vc biostimulants to enhance cold tolerance in grafted cucumbers, improving sustainable cultivation in low-temperature regions. Full article

Soil phosphorus (P) availability is an important determinant of productivity in Pinus massoniana (Masson pine) forests. The mechanistic bases governing the physiological and growth responses of Masson pine to varying soil P conditions remain insufficiently characterized. This study aims to decipher the adaptive strategies of Masson pine to different soil P levels, focusing on root morphological–architectural plasticity and the allocation dynamics of nutrient elements and photosynthetic assimilates. One-year-old potted Masson pine seedlings were exposed to four P addition treatments for one year: P0 (0 mg kg⁻¹), P1 (25 mg kg⁻¹), P2 (50 mg·kg⁻¹), and P3 (100 mg kg⁻¹). In July and December, measurements were conducted on seedling organ biomass, root morphological indices [root length (RL), root surface area (RSA), root diameter (RD), specific root length (SRL), and root length ratio (RLR) for each diameter grade], root architectural indices [number of root tips (RTs), fractal dimension (FD), root branching angle (RBA), and root topological index (TI)], as well as the content of nitrogen (N), phosphorus (P), carbon (C), and non-structural carbohydrates (NSCs) in roots, stems, and leaves. Compared with the P0 treatment, P2 and P3 significantly increased root biomass, root–shoot ratio, RL, RSA, RTs, RLR of finer roots (diameter ≤ 0.4 mm), nutrient accumulation ratio in roots, and starch (ST) content in roots, stems and leaves. Meanwhile, they decreased soluble sugar (SS) content, SS/ST ratio, C and N content, and N/P and C/P ratios in stems and leaves, as well as nutrient accumulation ratio in leaves. The P3 treatment significantly reduced RBA and increased FD and SRL. Our results indicated that Masson pine adapts to low P by developing shallower roots with a reduced branching intensity and promoting the conversion of ST to SS. P’s addition effectively alleviates growth limitations imposed by low P, stimulating root growth, branching, and gravitropism. Although a sole P addition promotes short-term growth and P uptake, it triggers a substantial consumption of N, C, and SS, leading to significant decreases in N/P and C/P ratios and exacerbating N’s limitation, which is detrimental to long-term growth. Under high-P conditions, Masson pine strategically prioritizes allocating limited N and SS to roots, facilitating the formation of thinner roots with low C costs. Full article

With the objective of identifying superior Vernicia montana trees grounded in phenotypic and agronomic traits, this study sought to develop and implement a comprehensive evaluation method which would provide a practical foundation for future clonal breeding initiatives. Using the Vernicia montana propagated from seedling forests grown in the Suxian District of Chenzhou City in southern Hunan Province, we conducted pre-selection, primary selection, and re-selection of Vernicia montana forest stands and took the nine trait indices of single-plant fruiting quantity, single-plant fruit yield, disease and pest resistance, fruit ripening consistency, fruit aggregation, fresh fruit single-fruit weight, fresh fruit seed rate, dry seed kernel rate, and seed kernel oil content rate as the optimal evaluation indexes and carried out cluster analysis and a comprehensive evaluation in order to establish a comprehensive evaluation system for superior Vernicia montana trees. The results demonstrated that a three-stage selection process—consisting of pre-selection, primary selection, and re-selection—was conducted using a comprehensive analytical approach. The pre-selection phase relied primarily on sensory evaluation criteria, including fruit count per plant, tree size, tree morphology, and fruit clustering characteristics. Through this rigorous screening process, 60 elite plants were selected. The primary selection was based on phenotypic traits, including single-plant fruit yield, pest and disease resistance, and uniformity of fruit ripening. From this stage, 36 plants were selected. Twenty plants were then selected for re-selection based on key performance indicators, such as fresh fruit weight, fresh fruit seed yield, dry seed kernel yield, and oil content of the seed kernel. Then the re-selected optimal trees were clustered and analyzed into three classes, with 10 plants in class I, 7 plants in class II, and 3 plants in class III. In class I, the top three superior plants exhibited outstanding performance across key traits: their fresh fruit weight per fruit, fresh fruit seed yield, dry seed yield, and seed kernel oil content reached 41.61 g, 42.80%, 62.42%, and 57.72%, respectively. Compared with other groups, these figures showed significant advantages: 1.17, 1.09, 1.12, and 1.02 times the average values of the 20 reselected superior trees; 1.22, 1.19, 1.20, and 1.08 times those of the 36 primary-selected superior trees; and 1.24, 1.25, 1.26, and 1.19 times those of the 60 pre-selected trees. Fruits counts per plant and the number of fruits produced per plant of the best three plants in class I were 885 and 23.38 kg, respectively, which were 1.13 and 1.18 times higher than the average of 20 re-selected superior trees, 1.25 and 1.30 times higher than the average of 36 first-selected superior trees, and 1.51 and 1.58 times higher than the average of 60 pre-selected superior trees. Class I superior trees, especially the top three genotypes, are suitable for use as mother trees for scion collection in grafting. The findings of this study provide a crucial foundation for developing superior clonal varieties of Vernicia montana through selective breeding. Full article

Efficient detection and localization of maize seedlings in complex field environments is essential for accurate plant segmentation and subsequent three-dimensional morphological reconstruction. To overcome the limited accuracy and high computational cost of existing models, we propose an enhanced architecture named MaizeStar-YOLO. The redesigned backbone integrates a novel C2F_StarsBlock to improve multi-scale feature fusion, while a PKIStage module is introduced to enhance feature representation under challenging field conditions. Evaluations on a diverse dataset of maize seedlings show that our model achieves a mean average precision (mAP) of 92.8%, surpassing the YOLOv8 baseline by 3.6 percentage points, while reducing computational complexity to 3.0 GFLOPs, representing a 63% decrease. This efficient and high-performing framework enables precise plant–background segmentation and robust three-dimensional feature extraction for morphological analysis. Additionally, it supports downstream applications such as pest and disease diagnosis and targeted agricultural interventions. Full article

In this study the objective was to morphologically characterize fruits, seeds and seedlings of Cereus fernambucensis Lem., as well as evaluate the seed germination and phenological dynamics of these columnar cacti, native to Brazil, which occur in restinga ecosystems. Biometric and morphological determinations were performed using 100 fruits, describing seed morphology in external and internal aspects and considering five stages of development for the characterization of seedlings. In the study of seed germination, two light conditions (12 h photoperiod and complete darkness) were tested under 25 °C, in a completely randomized design with four replicates of 50 seeds each. In the estimation of reproductive phenology, information was collected from herbarium specimens on the SpeciesLink online platform, and the exsiccatae were analyzed for the notes on their labels to evaluate reproductive aspects. Fruits showed an average mass of 21.11 g, length of 44.76 mm, diameter of 28.77 mm and about 336 seeds per fruit. Seeds behave as positive photoblastic, with a high percentage of germination under controlled conditions (94%). Germination is epigeal and phanerocotylar, with slow growth and, at 30 days after sowing, the seedling measures approximately 2 cm, which makes it possible to visualize the appearance of the epicotyl and the first spines. The species blooms and bears fruit throughout the year, with peaks of flowering and fruiting in January and March, respectively. The various characteristics make C. fernambucensis a key species for maintaining the biodiversity of restingas. Full article

Salt stress is one of the most common factors reducing the productivity of crops. We tested the effect of Rapamycin, an mTOR inhibitor and autophagy inducer, for the possible amelioration of high-salinity stress in Eruca sativa. We analyzed the germination rate, the macro- and micro-morphology of seedlings, and the ultrastructure of cotyledons with a Transmission Electron Microscope. The most striking observation was that salt stress blocked the catabolism of the lipid droplets stored in the embryos of E. sativa, also dramatically reducing the starch storage capability in the plastids. As a consequence, lipid droplets remained in the developing seedlings until a late stage. On the contrary, the catabolism of the lipid storage in the embryos in the presence of rapamycin and salt stress was comparable to the control, even if the starch stored in the plastids was lower. Rapamycin-induced autophagic activity was shown by characteristic ultrastructural changes, such as increased membrane recycling. Part of this activity was interpreted as pexophagy, i.e., the autophagy of peroxisomes, where an increase in their turnover rate could be necessary to maintain an active glyoxylate cycle. Full article

Guilandina bonduc L. is a pantropical coastal shrub with varied fruits and seeds, capable of germinating under saline stress. This study aimed to morphologically characterize the fruits and seeds of the species, correlate these characteristics, and evaluate the tolerance of seedlings to salt according to seed mass. Physical variables (length, width, thickness, and weight) were analyzed, and Spearman’s correlation was applied. Germination was tested with light seeds (<1.55 g) and heavy seeds (≥1.55 g) under five levels of salt stress, in a 2 × 5 factorial design. G. bonduc can produce seeds with variations in mass and size that are not necessarily related to fruit size. The reduction in osmotic potential resulted in lower seed germination and vigor; even so, the species demonstrated tolerance to salt stress, maintaining germination rates above 50% even under conditions of −1.0 MPa, regardless of seed mass. Lighter seeds germinate more quickly and uniformly, while heavier seeds produce more vigorous seedlings, especially in the absence of salinity, and are therefore more suitable for seedling production. These results indicate that G. bonduc has potential for revegetation of saline areas, being useful in adaptation to climate change due to its tolerance to saline stress and the relationship between seed mass and seedling vigor. Full article

Amid global environmental change, the intensification of nitrogen (N) deposition exerts critical impacts on the growth of forest vegetation and the structure and function of ecosystems in subtropical China. However, the physiological and growth response mechanisms of subtropical tree species remain poorly understood. This study explored adaptive mechanisms of typical subtropical tree species to N deposition, analyzing biomass accumulation, root plasticity, and nutrient/photosynthate allocation strategies. One-year-old potted seedlings of Phyllostachys edulis (moso bamboo) and Cunninghamia lanceolata (Chinese fir) were subjected to four N-addition treatments (N0: 0, N1: 6 g·m⁻²·a⁻¹, N2: 12 g·m⁻²·a⁻¹, N3: 18 g·m⁻²·a⁻¹) for one year. In July and December, measurements were conducted on seedling organ biomass, root morphological and architectural traits, as well as nutrient elements (N and phosphorus(P)) and non-structural carbohydrate (soluble sugars and starch) contents in roots, stems, and leaves. Our results demonstrate that the Chinese fir exhibits stronger tolerance to N deposition and greater root morphological plasticity than moso bamboo. It adapts to N deposition by developing root systems with a higher finer root (diameter ≤ 0.2 mm) ratio, lower construction cost, greater branching intensity and angle, and architecture approaching dichotomous branching. Although N deposition promotes short-term biomass and N accumulation in both species, it reduces P and soluble sugars contents, leading to N/P imbalance and adverse effects on long-term growth. Under conditions of P and photosynthate scarcity, the Chinese fir preferentially allocates soluble sugars to leaves, while moso bamboo prioritizes P and soluble sugars to roots. In the first half of the growing season, moso bamboo allocates more biomass and N to aboveground parts, whereas in the second half, it allocates more biomass and P to roots to adapt to N deposition. This study reveals that Chinese fir enhances its tolerance to N deposition through the plasticity of root morphology and architecture, while moso bamboo exhibits dynamic resource allocation strategies. The research identifies highly adaptive root morphological and architectural patterns, demonstrating that optimizing the allocation of elements and photosynthates and avoiding elemental balance risks represent critical survival mechanisms for subtropical tree species under intensified N deposition. Full article

Arbuscular mycorrhizal fungi (AMF) symbiosis has great potential in improving grapevine performance and reducing external input dependency in viticulture. However, the precise, strain-specific impacts of different AMF species on ‘Summer Black’ grapevine cuttings across multiple physiological and morphological dimensions remain underexplored. To address this, we conducted a controlled greenhouse pot experiment, systematically evaluating four different AMF species (Diversispora versiformis, Diversispora spurca, Funneliformis mosseae, and Paraglomus occultum) on ‘Summer Black’ grapevine cuttings. All AMF treatments successfully established root colonization, with F. mosseae achieving the highest infection rate. In detail, F. mosseae notably enhanced total root length, root surface area, and volume, while D. versiformis specifically improved primary adventitious and 2nd-order lateral root numbers. Phosphorus (P) uptake in both leaves and roots was significantly elevated across all AMF treatments, with F. mosseae leading to a 42% increase in leaf P content. Furthermore, AMF inoculation generally enhanced the activities of catalase, superoxide dismutase, and peroxidase, along with soluble protein and soluble sugar contents in leaves and roots. Photosynthetic parameters, including net photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (Tr), were dramatically increased in AMF-colonized cutting seedlings. Whereas, P. occultum exhibited inhibitory effects on several growth metrics, such as shoot length, leaf and root biomass, and adventitious lateral root numbers, and decreased the contents of Nitrogen (N), potassium (K), magnesium (Mg), and iron (Fe) in both leaves and roots. These findings conclusively demonstrate that AMF symbiosis optimizes root morphology, enhances nutrient acquisition, and boosts photosynthetic efficiency and stress resilience, thus providing valuable insights for developing targeted bio-fertilization strategies in sustainable viticulture. Full article

The distinctive leaf and twig heteromorphism in Euphrates poplar (Populus euphratica Oliv.) reflects its adaptive strategies to cope with arid environments across ontogenetic stages. In the key distribution area of P. euphratica forests in China, we sampled P. euphratica twigs (which grow in the current year) at different age classes (1-, 3-, 5-, 8-, and 11-year-old trees), then analyzed their morphological traits, biomass allocation, as well as allometric relationships. Results revealed significant ontogenetic shifts: seedlings prioritized vertical growth by lengthening stems (32.06 ± 10.28 cm in 1-year-olds) and increasing stem biomass allocation (0.36 ± 0.14 g), while subadult trees developed shorter stems (6.80 ± 2.42 cm in 11-year-olds) with increasesd petiole length (2.997 ± 0.63 cm) and lamina biomass (1.035 ± 0.406 g). Variance partitioning showed that 93%–99% of the trait variation originated from age and individual differences. Standardized major axis analysis demonstrated a consistent “diminishing returns” allometry in biomass allocation (lamina–stem slope = 0.737, lamina–petiole slope = 0.827), with age-modulated intercepts reflecting developmental adjustments. These patterns revealed an evolutionary trade-off strategy where subadult trees optimized photosynthetic efficiency through compact architecture and enhanced hydraulic safety, while seedlings prioritized vertical space occupation. Our findings revealed that heteromorphic twigs play a pivotal role in modular trait coordination, providing mechanistic insights into P. euphratica’s adaptation to extreme aridity throughout its lifespan. Full article

This study investigated how Leucaena leucocephala, a dry forest plant, copes with soil copper and herbivory caused by Schistocerca piceifrons, crucial for understanding species adaptation in stressed environments. A 33-day factorial experiment with three copper and two herbivory treatments assessed seedling growth rates (relative growth rate of biomass—RGR_B, and leaf area—RGR_LA), morphology, net assimilation rate (NAR), biomass allocation, and survival. Seedlings demonstrated compensatory growth in terms of RGR_B and RGR_LA under high copper and herbivory. Although copper decreased overall survival, surviving individuals effectively compensated for herbivory damage. These tolerance responses, primarily driven by an increased NAR (accounting for 98% of compensation), aligned with the limiting resource model. While most morphological components remained stable, herbivory specifically increased the root–shoot ratio. These findings indicate L. leucocephala possesses significant resilience through physiological adjustments, like enhancing NAR, and biomass reallocation strategies, allowing it to persist despite multiple stressors common in dry forests. Full article

The promising field of low-temperature plasma treatment, known for its non-invasive and environmentally sustainable nature, is being actively investigated for its ability to enhance germination, emergence, yield, and overall plant development in a broad spectrum of crops. For gene bank requirements, low-temperature plasma technologies can also improve germination parameters and promote the development seeds suitable for long-term storage. Seeds from four selected cultivars of wheat, oats, flax, and rapeseed stored in the gene bank for 1, 10, and 20 years were subjected to plasma treatments for 20, 25, and 30 min. The study evaluated the mean root and shoot length, root–shoot ratio, and seedling vigour index. Additionally, the malondialdehyde level, total polyphenol content, total flavonoid content, and total antioxidant capacity were analysed. Plasma treatment displayed varying effects on the morphological characteristics and antioxidant activity of the tested cultivars, which were influenced by treatment duration and cultivar. A positive effect of plasma treatment on seedling length, seedling vigour index, and root–shoot ratio was observed in flax cultivar ‘N-9/62/K3/B’ in all periods and in variants T2 and T3. Conversely, the wheat cultivar ‘Granny’ showed variable results, and the oat cultivar ‘Risto’ showed variable negative results in regards to mean root length and mean shoot length after plasma treatment. The indicators of oxidative stress and antioxidant capacity were affected in all the cultivars studied. A positive effect of plasma treatment on these indicators was observed in the wheat cultivar ‘Granny’, while flax cultivar ‘N-9/62/K3/B’ exhibited inconsistent results. While in cereals, a decrease in malondialdehyde content after plasma treatment was associated with an increase in polyphenol and flavonoid content as the treatment duration increased, small-seeded species responded somewhat differently. The rapeseed cultivar ‘Skrivenskij’ and flax cultivar ‘N-9/62/K3/B’ showed an increase in polyphenol and flavonoid content following a decrease in malondialdehyde levels. This study highlights the potential of low-temperature plasma treatment for long-term-stored seeds and its applicability to plant genetic resources. The findings emphasize the need for the further optimization of low-temperature plasma treatment conditions for different plant species and cultivars. Full article

Plant-beneficial microbes are a perennial ally in an agroecosystems, providing multiple benefits to crop plants. The present study explored the potential of two microbial biocontrol agents (MBCAs), viz., Trichoderma asperellum and Pseudomonas fluorescens, against the bacterial blight pathogen of rice, Xanthomonas oryzae pv. oryzae. In vitro, MBCAs resulted in significant inhibition of X. oryzae pv. oryzae, as evidenced through the distortion of pathogen cell morphology and formation of a pathogen biofilm. Pot studies on the effect of MBCAs in rice showed increased germination, increased vigor index of seedlings, increased tiller numbers, a 10.29% reduction in percentage disease incidence (PDI), and low disease severity following individual inoculation. Activity of plant defense enzymes also increased with MBCA treatment (phenylalanine ammonia-lyase, 2.7-fold increase; peroxidase and polyphenol oxidase, 5-fold increase), establishing the priming effect of MBCAs on host defense. The quantitative polymerase chain reaction data revealed that pathogenesis-related genes (OsPR1a, OsPR1b, and OsPR10a) and X. oryzae pv. oryzae resistance genes (Xa1 and Xa26) were upregulated 4- to 14-fold in MBCA-treated rice plants over control plants. These results provide insights into the phenological, physiological, and molecular responses of rice crops treated with MBCAs in the presence of X. oryzae pv. oryzae and could be used to develop an effective field management strategy. Full article

Weak seedlings and poor growth uniformity affect the mechanical transplanting of densely sown rice seedlings. To address these issues, seedlings of the conventional japonica rice “Zhehexiang 2” were grown in a traditional flat tray (control), pot-mat tray (26 × 52 bowls; BT(26)), and pot-mat tray (30 × 58 bowls; BT(30)) to compare the effects of different specifications of pot-mat trays (BTs) on the growth and quality of mechanical transplanting of densely sown rice seedlings with 250 g/tray. The BT-raised seedlings showed improved seedling quality, with increases in the shoot and root dry weights by 7.44% and 20.11%, respectively, compared to the flat tray. Under the dense sowing rate, the plant height uniformity of the BT(26) and BT(30) treatments was significantly increased by 6.95% and 3.43%, and the root entwining force of the seedlings was 14.28% and 10.21% higher, respectively, compared with those of the control. The missing hill rate for BT-raised seedlings after mechanical transplanting was significantly reduced by 53.15%. The loss of roots during mechanical transplanting was reduced. Compared with the control, the root length, root surface area, and root number were increased, and a greater number of large roots were retained, which promoted the early development of seedlings after mechanical transplanting. The proportion of holes with two to five seedlings was higher after mechanical transplanting. The pot-mat tray divided the root growth area of seedlings, promoted the growth of the seedlings, and reduced the root loss and missing hill rate under the high sowing rate. Thus, the quality of mechanical transplanting of densely sown seedlings was improved. Full article

Elevated [CO₂] enhances light interception and carboxylation efficiency in plants. The combined effects of [CO₂] and photosynthetic photon flux density (PPFD) on stomatal morphology, leaf anatomy, and photosynthetic capacity in tomato seedlings remain unclear. This study subjected tomato seedlings (Solanum lycopersicum Mill. cv. Jingpeng No.1) to two [CO₂] (ambient [a[CO₂], 400 µmol·mol⁻¹] and enriched [e[CO₂], 800 µmol·mol⁻¹]) and three PPFD levels (L; low[Ll: 200 µmol·m⁻²·s⁻¹], moderate[Lm: 300 µmol·m⁻²·s⁻¹], and high[Lh: 400 µmol·m⁻²·s⁻¹]) to assess their interactive impacts. Results showed that e[CO₂] and increased PPFD synergistically improved relative growth rate and net assimilation rate while reducing specific leaf area and leaf area ratio. Notably, e[CO₂] decreased stomatal aperture (−13.81%) and density (−27.76%), whereas elevated PPFD promoted stomatal morphological adjustments. Additionally, Leaf thickness increased by 72.98% under e[CO₂], with Lm and Lh enhancing this by 10.79% and 41.50% compared to Ll. Furthermore, photosynthetic performance under e[CO₂] was further evidenced by improved chlorophyll fluorescence parameters (excluding non-photochemical quenching). While both e[CO₂] and increased PPFD Photosynthetic performance under e[CO₂] was further evidenced by improved chlorophyll fluorescence parameters (excluding non-photochemical quenching). Moreover, e[CO₂]-Lh treatment maximized total dry mass and seedling health index. Correlation analysis indicated that synergistic optimization of stomatal traits and leaf structure under a combination of e[CO₂] and increased PPFD enhanced light harvesting and CO₂ diffusion, thereby promoting carbon assimilation. These findings highlight e[CO₂]-Lh as an optimal strategy for tomato seedling growth, providing empirical guidance for precision CO₂ fertilization and light management in controlled cultivation. Full article