Polygonati Rhizoma demonstrates significant potential for addressing both chronic and hidden hunger. The supply of high-quality seedlings is a primary factor influencing the development of the Polygonati Rhizoma industry. Warm water soaking is often used in agriculture to promote the rapid germination of seeds, while its application and molecular mechanism in Polygonati Rhizoma have not been reported. To rapidly obtain high-quality seedlings, this study treated Polygonatum kingianum var. grandifolium seeds with sand storage at low temperatures, warm water soaking, and cultivation temperature gradients. The results showed that the culture at 25 ℃ or sand storage at 4 ℃ for 2 months rapidly broke the seed dormancy of P. kingianum var. grandifolium, while the culture at 20 ℃ or sand storage at 4 ℃ for 1 month failed to break the seed dormancy. Soaking seeds in 60 ℃ warm water further increased the germination rate, germination potential, and germination index. Specifically, the seeds soaked at 60 ℃ and cultured at 25 ℃ without sand storage treatment(Aa25) achieved a germination rate of 78. 67%±1. 53% on day 42 and 83. 40%±4. 63% on day 77. The seeds pretreated with sand storage at 4 ℃ for 2 months, soaked in 60 ℃ water, and then cultured at 25 ℃ achieved a germination rate comparable to that of Aa25 on day 77. Transcriptomic analysis indicated that warm water soaking might promote germination by triggering reactive oxygen species( ROS), inducing the expression of heat shock factors( HSFs) and heat shock proteins( HSPs), which accelerated DNA replication, transcript maturation, translation, and processing, thereby facilitating the accumulation and turnover of genetic materials. According to the results of indoor controlled experiments and field practices, maintaining a germination and seedling cultivation environment at approximately 25 ℃ was crucial for the one-year seedling cultivation of P. kingianum var. grandifolium.
Germination ; Seedlings/genetics* ; Water/metabolism* ; Seeds/metabolism* ; Polygonatum/genetics* ; Temperature ; Plant Proteins/genetics* ; Plant Dormancy

Callicarpa is an important medicinal plant in China, which has hemostatic, antibacterial, and antioxidant pharmacological effects, and the efficacy of astringing and arresting bleeding, clearing heat and detoxification, activating blood, and resolving stasis is outstanding. At the same time, Callicarpa can be used as an ornamental plant because of its gorgeous flowers and fruits. Callicarpa has good market development prospects, but the long seed reproduction cycle directly limits the large demand for seedlings in its industrial development. Asexual reproduction technology is the basis for the industrialization development of Callicarpa, which is helpful in producing high-quality seedlings and medicinal materials. Although Chinese and foreign scholars have achieved remarkable results in the study of asexual reproduction of Callicarpa, there is no report on the large-scale production of seedlings of Callicarpa. Integrating and improving its asexual reproduction technology can promote the development and utilization of Callicarpa, improve its medicinal value, and create significant economic benefits. Therefore, the authors reviewed the effects of cutting, season, plant growth regulators, substrates, environment, and management measures on the cutting of Callicarpa and the research progress of tissue culture propagation affected by explants, basic media, exogenous additives, subculture cycles, culture conditions, and transplanting substrates. The mechanism of adventitious root formation was reviewed at the cellular, physiological, and biochemical levels, so as to put forward the problems and corresponding solutions in the study of asexual propagation technology and regulatory mechanism of Callicarpa and point out the future research directions. The study aims to provide a reference for in-depth research on the asexual propagation technology of Callicarpa and the commercial production of its high-quality seedlings.
Reproduction, Asexual ; Plants, Medicinal/physiology* ; Seedlings/growth & development* ; Tissue Culture Techniques

Accurately obtaining the crop quantity and density is not only crucial for the demand-based input of water and fertilizer in the field but also vital for ensuring the yield and quality of crops. Aerial photography by unmanned aerial vehicles (UAVs) can quickly acquire the distribution image information of crops over a large area. However, the accurate recognition of a single type of dense targets is a huge challenge for most recognition algorithms. Taking banana seedlings as an example in this study, we captured the images of banana plantations by UAVs from high altitudes to explore an efficient recognition method for dense targets. We proposed a strategy of "cut-recognition-stitch" and constructed a counting method based on the improved Faster R-CNN algorithm. First, the images containing highly dense targets were cropped into a large number of image tiles according to different sizes (simulating different flight altitudes), and the Contrast Limited Adaptive Histogram Equalization (CLAHE) algorithm was adopted to improve the image quality. A banana seedling dataset containing 36 000 image tiles was constructed. Then, the Faster R-CNN network with optimized parameters was used to train the banana seedling recognition model. Finally, the recognition results were reversely stitched together, and a boundary deduplication algorithm was designed to correct the final counting results to reduce the repeated recognition caused by image cropping. The results show that the recognition accuracy of the Faster R-CNN with optimized parameters for banana image datasets of different sizes can reach up to 0.99 at most. The deduplication algorithm can reduce the average counting error for the original aerial images from 1.60% to 0.60%, and the average counting accuracy of banana seedlings reaches 99.4%. The proposed method effectively addresses the challenge of recognizing dense small objects in high-resolution aerial images, providing an efficient and reliable technical solution for intelligent crop density monitoring in precision agriculture.
Musa/growth & development* ; Crops, Agricultural/growth & development* ; Algorithms ; Neural Networks, Computer ; Unmanned Aerial Devices ; Seedlings/growth & development* ; Image Processing, Computer-Assisted/methods* ; Photography ; Agriculture/methods*

Rice (Oryza sativa L.), as a thermophilic crop, is highly susceptible to cold stress during its growth process. Chilling injury at the plumule stage and seedling stage often affects the morphological development and leads to yield reduction of rice. The exploration and utilization of cold tolerance genes are among the most direct and effective approaches to address cold stress in rice. To identify quantitative trait loci (QTLs) associated with cold tolerance at plumule and seedling stages, in this study, we measured the seedling rates and survived seedling rates of the indica rice cultivar 'HZ', the japonica cultivar 'Nekken2', and their 120 recombinant inbred lines (RILs) under cold stress. A previously constructed high-density genetic linkage map was used for the mapping of the QTLs conferring cold tolerance at the plumule and seedling stages. A total of 4 QTLs for plumule-stage cold tolerance and 9 QTLs for seedling-stage cold tolerance were detected, with the maximum limit of detection reaching 5.20. Notably, a genetically overlapping QTL for both plumule and seedling stages was identified on chromosome 8, spanning a physical interval of 24 432 953-25 295 129 bp. Candidate genes within the detected QTL intervals were screened, and quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to analyze the gene expression during the plumule and seedling stages. The results revealed that LOC_Os03g06570, LOC_Os03g07100, LOC_Os06g08280, LOC_Os08g38440, LOC_Os08g39100, and LOC_Os08g39540 exhibited significantly differential expression between the parental lines. These genes were either significantly downregulated or upregulated under cold stress. Among them, the first three gene (LOC_Os03g06570, LOC_Os03g07100, and LOC_Os06g08280) were hypothesized to be key candidates regulating the cold tolerance of rice seedlings, while the latter three genes (LOC_Os08g38440, LOC_Os08g39100, and LOC_Os08g39540) were identified as comprehensive regulators of cold tolerance during both plumule and seedling stages. These findings lay a foundation for the fine mapping and cloning of cold tolerance genes at the plumule and seedling stages, providing valuable insights for breeding cold-tolerant rice varieties.
Quantitative Trait Loci/genetics* ; Oryza/growth & development* ; Seedlings/growth & development* ; Cold Temperature ; Chromosome Mapping ; Gene Expression Regulation, Plant

Phytoremediation plays an important role in the treatment of heavy metal pollution in soil. In order to elucidate the mechanism of salicylic acid (SA) on copper absorption, seedlings from Xuzhou (with strong Cu-tolerance) and Weifang Helianthus tuberosus cultivars (with weak Cu-tolerance) were selected for pot culture experiments. 1 mmol/L SA was sprayed upon 300 mg/kg soil copper stress, and the photosynthesis, leaf antioxidant system, several essential mineral nutrients and the changes of root upon copper stress were analyzed to explore the mechanism of copper resistance. The results showed that Pn, Tr, Gs and Ci upon copper stress decreased significantly compared to the control group. Meanwhile, chlorophyll a, chlorophyll b and carotenoid decreased with significant increase in initial fluorescence (F₀), maximum photochemical quantum yield of PSⅡ (Fv/Fm), electron transfer rate (ETR) and photochemical quenching coefficient (qP) content all decreased. The ascorbic acid (AsA) content was decreased, the glutathione (GSH) value was increased, the superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) activity in the leaves were decreased, and the peroxidase (POD) activity was significantly increased. SA increased the Cu content in the ground and root system, and weakened the nutrient uptake capacity of K, Ca, Mg, and Zn in the root stem and leaves. Spray of exogenous SA can maintain the opening of leaf stomata, improve the adverse effect of copper on photosynthetic pigment and PSⅡ reaction center. Mediating the SOD and APX activity started the AsA-GSH cycle process, effectively regulated the antioxidant enzyme system in chrysanthemum taro, significantly reduced the copper content of all parts of the plant, and improved the ion exchange capacity in the body. External SA increased the content of the negative electric group on the root by changing the proportion of components in the root, promoted the absorption of mineral nutrient elements and the accumulation of osmoregulatory substances, strengthened the fixation effect of the root on metal copper, and avoided its massive accumulation in the H. tuberosus body, so as to alleviate the inhibitory effect of copper on plant growth. The study revealed the physiological regulation of SA upon copper stress, and provided a theoretical basis for planting H. tuberosus to repair soil copper pollution.
Antioxidants ; Copper ; Helianthus/metabolism* ; Salicylic Acid/pharmacology* ; Chlorophyll A/pharmacology* ; Spectroscopy, Fourier Transform Infrared ; Chlorophyll/pharmacology* ; Ascorbic Acid ; Superoxide Dismutase/metabolism* ; Photosynthesis ; Glutathione ; Plant Leaves ; Stress, Physiological ; Seedlings

Wilt disease is a major disease of cultivated Salvia miltiorrhiza, which is caused by Fusarium oxysporum. Since the infection process of F. oxysporum in plants is affected by environment factors, this study was conducted to reveal the relationship between disease severity and concentration of the pathogen in plants in the infection process of F. oxysporum in seedlings of S. miltiorrhiza by pot experiments and to reveal the effects of temperature and humidity on the infection process. The results showed that, after inoculation of S. miltiorrhiza seedlings with F. oxysporum, the pathogen in different parts was detected at different time, and it was first detected in substrates. With the continuous propagation of the pathogen(4-5 d), it gradually infected the roots and stems of the seedlings, and the plants had yellowing leaves and withering. The number of the pathogen reached the maximum in each part after 7-8 d, and then gradually decreased in the later stage of the disease. The concentration of the pathogen in substrates, roots and stems of S. miltiorrhiza showed a trend of decreasing after increasing with the aggravation of the disease and reached the maximum in the samples of moderate morbidity, while the concentration in the samples of severe morbidity decreased. In addition, the infection of F. oxysporum in seedlings of S. miltiorrhiza was affected by temperature and humidity. The suitable temperature was 25-30 ℃ and the suitable humidity was 80%-90%. This study could provide guidance for the experiments on pathogenicity of F. oxysporum, screening of biocontrol bacteria and controlling of wilt.
Seedlings/microbiology* ; Salvia miltiorrhiza ; Temperature ; Humidity ; Fusarium

Circular RNAs (circRNAs) are endogenous non-coding RNAs with covalently closed structures, which have important functions in plants. However, their biogenesis, degradation, and function upon treatment with gibberellins (GAs) and auxins (1-naphthaleneacetic acid, NAA) remain unknown. Here, we systematically identified and characterized the expression patterns, evolutionary conservation, genomic features, and internal structures of circRNAs using RNase R-treated libraries from moso bamboo (Phyllostachys edulis) seedlings. Moreover, we investigated the biogenesis of circRNAs dependent on both cis- and trans-regulation. We explored the function of circRNAs, including their roles in regulating microRNA (miRNA)-related genes and modulating the alternative splicing of their linear counterparts. Importantly, we developed a customized degradome sequencing approach to detect miRNA-mediated cleavage of circRNAs. Finally, we presented a comprehensive view of the participation of circRNAs in the regulation of hormone metabolism upon treatment of bamboo seedlings with GA and NAA. Collectively, our study provides insights into the biogenesis, function, and miRNA-mediated degradation of circRNAs in moso bamboo.
RNA, Circular/metabolism* ; Multiomics ; Poaceae/metabolism* ; Seedlings/genetics* ; Hormones/metabolism* ; MicroRNAs/metabolism* ; Gene Expression Regulation, Plant

In summer in 2020, Pinellia ternata in many planting areas in Hubei suffered from serious southern blight, as manifested by the yellowing and wilted leaves and rotten tubers. This study aims to identify the pathogen, clarify the biological characteristics of the pathogen, and screen fungicides. To be specific, the pathogen was isolated, purified, and identified, and the pathogenicity was detected according to the Koch's postulates. Moreover, the biological characteristics of the pathogen were analyzed. Furthermore, PDA plates and seedlings were used to determine the most effective fungicides. The results showed that the mycelia of the pathogen were white and villous with silk luster, which produced a large number of white to black brown sclerotia. The pathogen was identified as Athelia rolfsii by morphological observation and molecular identification based on LSU and TEF gene sequences. The optimum growth conditions for A. rolfsii were 30 ℃ and pH 5-8, and the optimum conditions for the germination of sclerotia were 25 ℃ and pH 7-9. Bacillus subtilis, difenoconazole, and flusilazole were identified as effective fungicides with PDA, and their half maximal effective concentration(EC_(50)) was all less than 5 mg·L~(-1). The effective fungicides screened with the seedlings were hymexazol and difenoconazole. Based on the screening experiments, difenoconazole can be used as the main agent for the prevention and treatment of southern blight.
Pinellia/genetics* ; Fungicides, Industrial/pharmacology* ; Seedlings ; Bacillus subtilis ; Mycelium

Grape (Vitis vinifera L.) in production is frequently exposed to inadequate light, which significantly affects its agronomic traits via inhibiting their physiological, metabolic and developmental processes. To explore the mechanism how the grape plants respond to the weak light stress, we used 'Yinhong' grape and examined their physiology-biochemistry characteristics and transcriptional profile under different levels of weak light stress. The results showed that grape seedlings upon low intensity shading treatments were not significantly affected. As the shading stress intensity was strengthened, the epidermis cells, palisade tissue, and spongy tissue in the leaves were thinner, the intercellular space between the palisade tissue and spongy tissue was larger compared with that of the control, and the activities of superoxide dismutase, catalase and peroxidase were decreased gradually. Additionally, the soluble protein content increased and the free proline content decreased gradually. Compared with the control, significant changes in plant photosynthetic characteristics and physiology-biochemistry characteristics were observed under high intensity of shading (80%). RNA-seq data showed that the differentially expressed genes between CK and T2, CK and T4, T2 and T4 were 13 913, 13 293 and 14 943, respectively. Most of the enrichment pathways were closely related with the plant's response to stress. Several signaling pathways in response to stress-resistance, e.g. JA/MYC2 pathway and MAPK signal pathway, were activated under weak light stress. The expression level of a variety of genes related to antioxidation (such as polyphenol oxidase and thioredoxin), photosynthesis (such as phytochrome) was altered under weak light stress, indicating that 'Yinhong' grape may activate the antioxidation related pathways to cope with reactive oxygen species (ROS). In addition, it may activate the expression of photosynthetic pigment and light reaction structural protein to maintain the photosynthesis activity. This research may help better understand the relevant physiological response mechanism and facilitate cultivation of grape seedlings under weak light.
Vitis/metabolism* ; Gene Expression Regulation, Plant ; Photosynthesis/genetics* ; Plant Leaves ; Light ; Seedlings/metabolism*

Seed quality plays an important role in the agricultural and animal husbandry production, the effective utilization of genetic resources, the conservation of biodiversity and the restoration and reconstruction of plant communities. Seed aging is a common physiological phenomenon during storage. It is a natural irreversible process that occurs and develops along with the extension of seed storage time. It is not only related to the growth, yield and quality of seed and seedling establishment, but also has an important effect on the conservation, utilization and development of plant germplasm resources. The physiological mechanisms of seed aging are complex and diverse. Most studies focus on conventional physiological characterization, while systematic and comprehensive in-depth studies are lacking. Here we review the recent advances in understanding the physiology of seed aging process, including the methods of seed aging, the effect of aging on seed germination, and the physiological and molecular mechanisms of seed aging. The change of multiple physiological parameters, including seed vigor, electrical conductivity, malondialdehyde content and storage material in the seed, antioxidant enzyme activity and mitochondrial structure, were summarized. Moreover, insights into the mechanism of seed aging from the aspects of transcriptome, proteome and aging related gene function were summarized. This study may facilitate the research of seed biology and the conservation and utilization of germplasm resources.
Germination ; Plants ; Proteome ; Seedlings ; Seeds/genetics*