Chinese Cabbage Seeds Research Articles

Deteksi Bakteri Pseudomonas cichorii Terbawa Benih Sawi Putih Impor Asal Korea Selatan dengan Metode PCR

Chinese cabbage (Brassica pekinensis L.) is one of the horticultural commodities that has a high production level in Indonesia. The increase in chinese cabbage production means that the need for chinese cabbage seeds in Indonesia is met through imported. The entry of seeds into a country through imported activities has the potential to as carriers of pathogens, especially bacteria that are OPTK A1 and A2, so it is important to carry out early detection of pathogens to prevent their spread in Indonesia. This research aims to detect bacteria carried by chinese cabbage seeds from South Korea using the PCR (Polymerase Chain Reaction) method. The results of the observations did not find the target bacteria Pseudomonas cichorii.

Comparative metabolomic analyses reveal metabolites associated with seed deterioration in Chinese cabbage

Seed deterioration during storage results in a decline in vigor, which has a negative impact on agricultural production. However, the mechanisms responsible for ageing are still poorly understood. The aim of present study was to investigate the physiological, biochemical, and metabonomic changes in naturally aged Chinese cabbage (Brassica pekinensis L.) seeds, and identify potential markers of seed deterioration. In this study, Chinese cabbage seeds with different moisture contents (1 % and 4 %) were stored under ambient conditions for 13 years. We employed a biochemical and metabolomics approach to investigate the impact of seed deterioration on naturally aged Chinese cabbage seeds and to identify the types and variations of differentially accumulated metabolites. Our findings demonstrate that the initial storage moisture content has a significant impact on the loss of seed vigor. The seed lot with an initial moisture content of 1 % exhibited higher viability and vigor after natural storage. High-vigor seeds showed higher catalase (CAT) activity, lower H2O2 and malondialdehyde (MDA) content, and reduced electrolyte leakage. No significant difference was observed between the two seed lots in terms of superoxide dismutase (SOD) activity, peroxidase (POD) activity, and soluble protein content. Metabolite analysis revealed 1,117 differential metabolites between the two seed lots. The differential metabolites were associated with various aspects of seed ageing, including changes in glycerophospholipids, phytohormones, antibiotics, reduction of antioxidant substances and raffinose, degradation of triglycerides, accumulation of toxic compounds, and DNA damage. Longicamphenylone was the prominent metabolite in response to seed deterioration. Pathway enrichment analysis revealed that flavonoid biosynthesis, which is involved in scavenging reactive oxygen species(ROS), was the most significant metabolic pathway associated with seed deterioration. Our findings also present the initial evidence linking endogenous antibiotics with seed aging.

Analysis and Evaluation of Seed-Filling Performance of a Pneumatic Interference Precision Seeder for Small Cabbages

To address the current problems of poor seed-filling performance and seed leakage of the pneumatic seed filler for cabbage, we designed a pneumatic disturbing precision seed filler for cabbage based on the auxiliary disturbing seed-filling method. This seeder can completely perturb the seed population entering the bottom of the seed box casing during the seed-filling process, thereby increasing the initial velocity of the cabbage seeds, and facilitating the smooth progress of the seed-filling process. Firstly, we carried out a theoretical analysis based on the particle dynamics of the seed-filling process of the seeder and obtained the influencing factors affecting the seed-filling performance of the seeder. Secondly, through EDEM discrete element simulation, the average speed of the seed population, the disturbance frequency, and the degree of disturbance were used as the indicators to select the seed discharge disk structure with the best seed-filling performance. In the experimental aspect, a four-factor three-level orthogonal standardized test was conducted to evaluate the seed filling performance of the planter, using the seed suction qualification rate and the seed leakage rate as the evaluation indexes. The optimal structure of the seed discharge tray was selected through polarity analysis and ANOVA. The optimal combination of parameters for the seed-filling process of the planter was obtained; linear serrated disk, 40 rpm disk rotation speed, −2500 Pa negative fan pressure, and 1.2 mm aperture diameter. After comparative validation tests, the seed suction qualification rate of the seed absorber was 95.32%, and the leakage rate was 3.11%, which was in line with the agronomic planting of Chinese cabbage seeds.

Putative Spatiotemporal Changes in Inhibitor Activity during Cold Stratification of Sapium sebiferum Seeds

Putative Spatiotemporal Changes in Inhibitor Activity during Cold Stratification of Sapium sebiferum Seeds

Characterization and mechanism of seed dormancy in Symplocos paniculata.

Symplocos paniculata is a highly desirable oil species for biodiesel and premium edible oil feedstock. While germplasm preservation and breeding are crucial, the severity of seed dormancy poses a challenge to successful germination. We employed S. paniculata seeds as experimental materials and conducted an investigation into the types and causes of seed dormancy by analyzing the morphology and developmental characteristics of its embryo, exploring the water permeability property of the endocarp, and examining the presence of endogenous inhibitors, aiming to establish a theoretical foundation for overcoming seed dormancy and maximizing germplasm resource utilization. The findings revealed that the seed embryo had matured into a fully developed embryo, and no dormancy in terms of embryo morphology was observed. Upon reaching maturity, the endocarp of seeds undergoes significant lignification, resulting in notable differences in water absorption between cracked and intact seeds. The impermeability of the endocarp is one of the factors contributing to mechanical restriction. The different phases of endosperm extraction exerted varying effects on the germination of Chinese cabbage seeds, with the methanol phase exhibiting the most potent inhibitory effect. The presence of endogenous inhibitors emerged as the primary factor contributing to physiological dormancy in seeds. GC-MS analysis and validation trials revealed that fatty acids and phenolics, including hexadecanoic acid, oxadecanoic acid, and m-cresol, constituted the main types of endogenous inhibitory compounds found within the endosperm. These findings suggest that the seed dormancy in S. paniculata seeds has endocarp mechanical restriction, and the presence of endogenous inhibitors causes physiological dormancy.

Preliminary study on Bioassay of Capparis spinosa L. seed extract and seed germination.

The present study explored the germination inhibitors present in the seeds of Capparis spinosa L., a plant species that is known for its ecological significance in preventing wind erosion and fixing sand in desertified areas. Additionally, its roots, leaves, and fruits possess medicinal properties, and are used to treat a range of ailments such as rheumatism, tumors, and diabetes. However, the plant's low germination rate under natural conditions is a major limitation. We aimed to improve the germination of C. spinosa seeds by investigating the effects of various infusions of caper seeds on the germination and seedling growth of Chinese cabbage seeds. A range of chemical reagents, hormonal immersions, and sand storage treatments were used to determine the differences in the germination rate of C. spinosa seeds. Our results revealed that among the various water extract concentrations tested, 100% water extract exhibited the strongest inhibitory effect on the germination and growth of the cabbage seeds, with a germination rate of (70.00 ± 0.09)%. Furthermore, the inhibitory effects on the germination and growth of cabbage seeds were found to be strongest when treated with the extract solution 1, yielding a germination rate of (83.33 ± 0.02)%. Notably, the leaves of Chinese cabbage seedlings turned yellow-green and yellow after treatment with the extract solution. These findings highlight the potential inhibitory effects of C. spinosa seed extracts on seed germination and growth and suggest that further research is needed to better understand the underlying mechanisms. The results of the germination experiment with methanol extract showed a sharp decline in the germination rate of Chinese cabbage seeds treated with 50% methanol extract, to (4.67 ± 0.02)%. These findings indicate the presence of germination-inhibiting substances in caper seeds. The highest germination potential was observed when the caper seeds were soaked in 30% PEG, reaching 35.00%. The highest germination rate, 19.33%, was observed when the seeds were soaked in 250 mg/L GA3 and 25 mmol/L NaCl. These results suggest that the germination inhibitor present in caper seeds affects the germination of cabbage seeds as well. The highest germination rate was achieved when the seeds were soaked with gibberellin. It is hoped that the research on the germination-inhibiting substances in caper seeds will provide a scientific foundation for improving and refining the artificial propagation and cultivation methods of this species.

Screening plant growth-promoting bacteria from the rhizosphere of invasive weed Ageratina adenophora for crop growth.

Plant-growth promoting rhizobacteria (PGPR) play a vital role in soil fertility and crop production. The rhizosphere of many crop plants has been well documented by screening PGPR for their plant-growth promoting (PGP) mechanisms. However, the rhizosphere of grass species that may act as potential habitats for novel PGPR remains relatively unexplored. Ageratina adenophora is a noxious weed that has invaded more than 40 tropical and subtropical countries in Asia, Oceania, Africa, and Europe. Its presence has led to changes in plant species composition, reducing their biodiversity and destroying ecosystem function. In this study, we screened 1,200 bacterial strains isolated from the rhizosphere soil of A. adenophora in three floristic regions in Yunnan Province, China. Samples were screened for their in vitro ability for N-fixation, production of the plant growth regulator indole-3-acetic acid (IAA), and the synthesis of 1-amino-cyclopropane-1-carboxylate (ACC) deaminase, which controls the levels of ethylene in developing plant roots. We found that 144 strains showed at least one of these PGP attributes. 16S rRNA gene sequencing showed that most (62.5%) of the samples were bacteria closely related to members of the genera Pseudomonas (27 strains), Providencia (20 strains), Chryseobacterium (14 strains), Ensifer (12 strains), Enterobacter (nine strains), and Hafnia (eight strains). Their abundance and biodiversity in the soil of individual floristic regions correlate positively with the invasion history of A. adenophora. From these PGP bacterial strains, KM_A34 (Pantoea agglomerans), KM_C04 (Enterobacter asburiae), and KM_A57 (Pseudomonas putida), which had the greatest in vitro ability of N-fixation, and IAA and ACC deaminase production, respectively, were selected. The strains were evaluated for their effect on the seed germination and growth of soybean, faba bean, pea, wheat, and Chinese cabbage other than A. adenophora. Chamber experiments showed these strains significantly (P < 0.05) increased (14.2-43.4% over the controls) germination rates of the soybean, faba bean, pea, and/or Chinese cabbage seeds. They also reduced relative seed germination times (20.8-48.8% over the controls) of soy bean, faba bean and/or wheat seeds. Greenhouse pot experiments showed that they significantly (P < 0.05) promoted the aboveground and belowground height of plant foliage (12.1-23.1% and 11.5-31.4% over the controls, respectively) and/or the dry weights (16.1-33.5% and 10.6-23.4% over the controls, respectively) of the soy bean, faba bean, pea, wheat and/or Chinese cabbage. These data indicate that the rhizosphere microbiota of A. adenophora contain a PGPR pool that may be used as bioinoculants to improve the growth and productivity of these crops.

Calibration and analysis of discrete element simulation parameters of Chinese cabbage seeds

ObjectiveTo improve the accuracy of parameters used in discrete element simulation test of Chinese cabbage seeds harvesting process.MethodsFirstly, the key physical parameters of Chinese cabbage seeds were measured. According to the results, the discrete element simulation model was established and the value range of simulation test parameters was determined. Then, the actual repose angle of Chinese cabbage seeds was obtained by physical accumulation test using bottomless conical cylinder lifting method. Plackett-Burman test, steepest climb test, Box-Behnken test and parameter optimization test were carried out in sequence with the actual angle of repose as the response value. Finally, the obtained parameters are verified.Results1. The Plackett-Burman test showed that the seed-seed rolling friction coefficient, the seed-steel rolling friction coefficient, the seed-seed static friction coefficient, and the seed-steel static friction coefficient had significant effects on the repose angle of Chinese cabbage seeds (P<0.05). 2. The optimization test showed that the seed-seed rolling friction coefficient was 0.08, the seed-steel rolling friction coefficient was 0.109, the seed-seed static friction coefficient was 0.496, and the seed-steel static friction coefficient was 0.415. 3. The validation test showed that the repose angle of Chinese cabbage seeds under such parameter was 23.62°, and the error with the repose angle of the physical test was 0.73%.ConclusionThe study show that the discrete element simulation parameters of Chinese cabbage seeds model and calibration are reliable, which can provide reference for the discrete element simulation of Chinese cabbage seeds.

A Preliminary Study on Allelopathy and Potential Allelochemicals of Root Exudates from Solanum rostratum Dunal

Aims: In order to understand the role of allelopathy in invasion success, effects of root exudates from Solanum rostratum Dunal on germination and primary growth of wheat and cabbage seeds were studied by vitro bioassay. These results indicated the allelopathy of root exudates and would be helpful for understanding Solanum rostratum Dunal invasion. &#x0D; Study Design: The roots were washed clean for three times with distilled water before they were gathered in a big bucket. The container was filled with distilled water, enough to submerge the roots, and air was aerated constantly with an air pump. The water extract was collected per 24 hs and for four times totally. The water extract from Solanum rostratum was concentrated with a rotary evaporator at 40°C and deposited in a refrigerator at 4°C. All the root exudates were pooled around 1500 mL, and the fresh weight of Solanum rostratum used for exudates collection was 1208 g, the exudate concentration was then marked as 0.8g f w/mL.&#x0D; Place and Duration of Study: Solanum rostratum was grown in the greenhouse on April 15th, 2019, its seeds were collected from the invaded fields in Chaoyang city (Liaoning province, China).&#x0D; Methodology: Petri dish bioassay was applied to test the effects of root exudates of Solanum rostratum on the seeds of wheat and Chinese cabbage. For test of allelochemicals exudated through the root, The compounds in organic fraction of root exudates analysed by GC-MS.&#x0D; Results: These results indicated the allelopathy of root exudates and would be helpful for understanding Solanum rostratum Dunal invasion.&#x0D; Conclusion: Root exudates of Solanum rostratum contained some allelochemicals, which could inhibit the germination and radicle growth of wheat and Chinese cabbage, though the effects of root exudates on shoot growth are different, with a stimulation on Chinese cabbage while a inhibition on wheat. The difference indicated a selectivity of allelopathy effect of root exudates from Solanum rostratum Dunal.

大白菜种子柔性脱粒装置设计与试验

In order to solve the problems of low efficiency of artificial harvesting method and high breakage rate and undepurated rate of traditional threshing method, a new flexible threshing device of Chinese cabbage seeds was designed, which was composed of flexible round head nail teeth and circular tube concave plate. Hertz contact collision theory was used to analyze and determine the structural parameters of the new threshing unit. The interaction force of different threshing elements materials were analyzed by using EDEM. The feasibility of the flexible threshing unit was verified by the comparison test of the distribution of threshed mixture. Finally, the orthogonal test was carried out to study the influence of the movement parameters of each structure on the cleaning rate and the rate of undepurated, and the weight matrix method was used to optimize it. The results indicate that under the condition the rotating speed of the threshing cylinder 750 rpm, the concave clearance 20 mm, and the feeding rate 1.4 kg/s, the threshing performance of the flexible threshing unit was the best. At this time, the breaking rate was 0.064%, and the un-threshing rate was 0.67%, which both met the relevant industry standards.

Influence of film-coated Materials on Germination and Seedling Vigor of film-Coated Chinese Cabbage Seeds

Influence of film-coated Materials on Germination and Seedling Vigor of film-Coated Chinese Cabbage Seeds

Nanodiamond Batch Enriched with Boron: Properties and Prospects for Use in Agriculture

The batch of detonation nanodiamond (DB) containing impurities of B (DB-B) was obtained by explosion using TNT with hexagon (50/50). This DB-B contained 0.96 wt% of B. The obtained DB-B nanopowder's morphological features, texture, and mesostructure were investigated by SEM, SAXS, and low-temperature nitrogen adsorption. We tested both aqueous suspensions and silica sols containing 2.5 wt. % DND and 0.05-0.1 wt. % of DB-B for the pre-sowing treatment of Chinese cabbage seeds. As a result, the reliable positive effect of an aqueous suspension of DB-B (0.05-0.1 wt.%) was revealed on the following characteristics of seedlings (in relation to the control): the germination energy of Chinese cabbage seeds and germination increased by ~50-70%. Furthermore, a significant positive effect of DB-B on the morphological characteristics of Peking cabbage plants at the early stages of its development was revealed when using DB-B for pre-sowing seed treatment in combination with silica sol (an increase in the sprout length by ~ 20% and root length by ~ 50% in relation to the control) as well as the biomass of Chinese cabbage plants increased by ~ 100% (20 days after planting the treated seeds).

Endogenous metabolic content of the cutting positions and ndole-3-butyric acid influence rooting of Toona ciliata var. pubescens stem cuttings

Toona ciliata var. pubescens (family Meliaceae) is an endangered species of mahogany endemic to China. It is now under Class II protection, and stem cuttings are an important means for its clonal propagation. However, the metabolic changes that occur in the cuttings during adventitious root formation and how these are influenced by indole-3-butyric acid (IBA) are still unclear. This study investigated the influence of cutting positions (top, middle and base) on the rooting ability and the associated metabolic changes during adventitious root formation. We compared treatment with 800 mg l−1 IBA with controls. The results showed that the rooting percentage, taproots per cutting, and longest root length differed significantly depending on the cutting position. Base cuttings had the best rooting ability and exhibited the highest average rooting percentage, the longest roots, and most taproots per cutting. The contents of soluble sugar, starch, non-structural carbohydrates (NSCs) and soluble proteins, and the peroxidase (POD) activity, were significantly higher in base cuttings than in middle and top cuttings; however, polyphenol oxidase (PPO) activity did not differ significantly among the positions. Metabolic changes occurred during the cutting process. The levels of POD and PPO activities increased significantly until 20 days after planting, suggesting that this period is key for the induction of adventitious rooting in this species. In the rooting process, IBA promoted an increase in the contents of soluble sugar, starch, NSCs and soluble proteins in the stem cuttings and it also increased the activities of POD and PPO. Bark-water extract from the stem cuttings inhibited the germination of Chinese cabbage seeds in a concentration-dependent manner, irrespective of the cutting position.

Synthesis and Research of Functional Layers Based on Titanium Dioxide Nanoparticles and Silica Sols Formed on the Surface of Seeds of Chinese Cabbage

The problems of using synthetic titanium dioxide nanoparticles in agrochemistry as biologically active stimulants and micronutrient fertilizers are considered. Functional layers are formed on the surface of the seeds of chinese cabbage using commercial TiO2 P-25 nanopowder in the form of aqueous suspensions and in combination with tetraethoxysilane-based silica sols. The content of carbon and silicon on the surface of the seeds was studied before and after presowing treatment. The effect of TiO2 and additives of glycerol and polyethylene glycol on the surface morphology of the layers formed around the seed as a result of presowing treatment is analyzed. The positive effect of TiO2 nanoparticles on seed germination, the qualitative and quantitative composition of epiphytic microorganisms, the physiological state of seedlings, which stimulates plant growth and their resistance to stressors, including phytopathogenic microorganisms, was established. The synergistic effect of all factors (silica sol, TiO2 P-25 nanoparticles, a solution of macro- and microelements, polyols) on the growth and development of plants in the initial period of development is considered.

Experimental Study and Computer Simulation of Compression Characteristics and Crushing of Chinese Cabbage Seeds

HighlightsBasic physical properties and mechanical parameters related to moisture content and compression orientation.A discrete model of cabbage seed was established by discrete element method.Crushing simulation has high consistency and small deviation compared with physical experiment.Abstract. To reduce the mechanical damage to cabbage seeds during combined harvesting, storage, and processing and to explore the mechanism of grain breakage, the basic physical parameters, such as the 1000-grain weight and the triaxial size under different moisture content (6.38%~15.30%), and the compressive mechanical properties under different loading methods (ventral loading and lateral loading) were studied. The discrete element method was used to establish a BPM model of cabbage seed. The distribution law underlying macroscopic cracks, evolutionary mechanism of internal damage and the micromechanical response during the compression of cabbage seeds were simulated. The results showed that the triaxial size, 1000-grain weight, arithmetic mean diameter and geometric mean diameter of cabbage seeds were related to the moisture content. The crushing force and apparent elastic modulus were related to the moisture content and the loading method. The distribution law of macroscopic cracks during the simulation processing was consistent with the physical experiment, and it was accompanied by increases in cracks and changes in the internal stress. In comparing the crushing force-displacement curves under the two compression modes, the law of curves between physical and virtual experiments was similar, and the peak values were very close, which indicated the feasibility of using the discrete element method to simulate the crushing of cabbage seeds during the compression process. Keywords: Cabbage seeds, Compression test, Cracks, DEM, Stress.

Removal of heavy metals in sludge via joint EDTA-acid treatment: Effects on seed germination

Heavy metals (Cu, Pb, Zn, Ni, Cr, and Cd) were removed from sludge via joint treatment with ethylene diamine tetraacetic acid (EDTA) and three organic acids (citric acid, glutamic acid, or aspartic acid) at optimal EDTA-acid concentration ratios of 1:1, 1:2 and 2:1, respectively. Heavy metal removal rates and post-treatment nutrient retention in sludge was then analyzed. The effects of different proportions sludge and soil mixes on the germination of Chinese white cabbage (Brassica campestris L. ssp. Chinensis Makino) seeds was then studied, and the mechanism by which nutrient content in the soil/sludge mixture affects seed germination was explored. The results indicated that the removal rate of the heavy metals decreased in the order of Zn > Ni > Cd > Pb > Cu > Cr, when EDTA was used in conjunction with citric acid and glutamic acid. In contrast, when EDTA was combined with aspartic acid, the removal rate of the heavy metals decreased in the order of Ni > Zn > Cd > Cu > Pb > Cr. Regarding the effect of heavy metal removal and sludge nutrient retention, EDTA-citric acid and EDTA-aspartic acid treatment had optimum results at a 1:1 ratio, while EDTA-glutamic acid treatment was optimum at a 1:2 ratio. At an optimum sludge to soil ratio of 1:4, the germination and root elongation inhibition rate of Chinese white cabbage seeds could be promoted, and the sludge could meet standard agricultural requirements. SPSS correlation analysis demonstrated that the seed germination index and nutrient content in sludge/soil mixtures were significantly correlated, demonstrating the feasibility of sludge for agricultural purposes.

Harmless disposal and resource utilization of wastes from the lake in China: Dewatering, composting and safety evaluation of fertilizer

Removal of waste (cyanobacteria, macrophytes and sediment) from Chaohu Lake, a large freshwater lake in China, might cause secondary environmental pollution due to improper disposal. Bioleaching dewatering and composting were performed in this study to dispose these wastes. The results showed that bioleaching could effectively decrease the water content in the cyanobacteria-macrophytes-sediment mixture. The reduced nitrogen-loss rate and increased humus content were observed in the compost after inoculating with microbial agent. High-throughput DNA sequencing showed that the microbial inoculants influenced microbial community composition. The degradation rates of microcystin variant with leucine (MC-LR) and microcystin variant with arginine (MC-RR) in the treatment of composting plus microbial inoculation were significantly higher than those in the natural placement. Seeds of Chinese cabbage were grown in the soil supplemented with mature compost for 67 days. The content of heavy metals in the organic fertilizer, soil and cabbage were much lower than the corresponding limited values of the national standard in China. In conclusion, the cyanobacteria, macrophytes and sediment in China Chaohu Lake could be used safely as raw materials for composting.

Evaluation of tetracycline phytotoxicity by seed germination stage and radicle elongation stage tests: A comparison of two typical methods for analysis

Biological tests with plant seeds have been adopted in many studies to investigate the phytotoxicity of pollutants to facilitate the control of risks and remain to be optimized. In this work, the experiment with a small sample size (Experiment 1) and the experiment with a large one (Experiment 2) were designed to study the effect of tetracycline (TC) on Chinese cabbage (Brassica rapa L.) at seed germination and radicle elongation stages. At the former stage, germination number data were obtained to analyze the germination energy (GE) and to judge the probability of the number of germinated seeds (Pn) by the binomial distribution model in Experiment 1. While germination time-to-number data were obtained to analyze the mean time to germination (MGT), the estimate of mean time to germination (EMGT) by survival analysis method, the time to germination for 50% of total seeds (T50) and the germination rate (GR) besides GE in Experiment 2. At the latter stage, the data of radicle length (RL) were obtained in all the experiments and the influence from the former stage on this stage was excluded in Experiment 2 but not in Experiment 1. Results showed that TC had universal adverse effects on the latter stage but not on the former stage in the experiments. Considering the availability of germination data for statistical analysis and the robustness of RL data, the methods adopted in Experiment 2 were more feasible than those in Experiment 1. In addition, Chinese cabbage seeds with medium size have the character of rapid germination compared with the commonly used crop species and can be used to shorten the experimental cycle to study the responses of seeds to pollutants to evaluate the phytotoxicity.We introduced survival analysis method to analyze the germination time-to-number data obtained in seed germination test to evaluate the phytotoxicity of tetracycline.

Changes in respiration and structure of non-heading Chinese cabbage seeds during gradual artificial aging

Abstract The aging of seeds is a major problem in the agricultural sector. It is also a complex biological question that remains unclear for many crop seeds. In this experiment, we investigated how different ageing levels influence seeds germination, storage components, structure, respiration metabolism, and whether respiration is a promising indicator that can non-destructively evaluate seed aging. First, we obtained non-heading Chinese cabbage seeds with varying ageing levels by applying artificial aging treatments over a period of six days (0 d–6 d). Subsequently, respiration related indexes and ultrastructural observations were conducted. Our results showed that the respiratory rate remains low when seeds have a low water content. With the increased water content, the activities of respiratory-related enzymes, phosphohexose isomerase (PGI) and malate dehydrogenase (MDH), reached maximum levels when seeds were aged for two days. Respiration rates peaked one day later, followed by a rapid decline with increasing age. The ageing process consumed a large amount of storage components (e.g. soluble sugar, sucrose, and starch), leading to the degradation of mitochondria, proteasomes, fat bodies and cell nuclei in the aged seeds, which resulted in the reduction of respiratory rates. This, in turn, negatively affected seed germination. When seeds germinated (1 h–6 h, 1 d–6 d) under standard germination condition, the germination rate and respiratory rate showed significant correlation. Especially for 5 h and 6 h, the correlation coefficients reached 0.954 and 0.976 respectively. Measured at those times, respiratory rate should be a promising indicator for seed aging.

Plant Growth-Promoting Rhizobacteria Improved Salinity Tolerance of Lactuca sativa and Raphanus sativus.

Salinity stress is an important environmental problem that adversely affects crop production by reducing plant growth. The impacts of rhizobacterial strains to alleviate salinity stress on the germination of Lactuca sativa and Raphanus sativus seeds were assessed using different concentrations of NaCl. Plant growth-promoting rhizobacteria (PGPR) strains were also examined to improve the early germination of Chinese cabbage seeds under normal conditions. Lactobacillus sp. and P. putida inoculation showed higher radicle lengths compared with non-inoculated radish (Raphanus sativus) seeds. LAP mix inoculation increased the radicle length of lettuce (Lactuca sativa) seedlings by 2.0 and 0.5 cm at salinity stress of 50 and 100 mM NaCl concentration, respectively. Inoculation by Azotobacter chroococcum significantly increased the plumule and radicle lengths of germinated seeds compared with non-inoculated control. A. chroococcum increased the radicle length relative to the uninoculated seeds by 4.0, 1.0, and 1.5 cm at 50, 100, and 150 mM NaCl concentration, respectively. LAP mix inoculation significantly improved the radicle length in germinated radish seeds by 7.5, 1.3, 1.2, and 0.6 cm under salinity stress of 50, 100, 150, and 200 mM NaCl concentration, respectively. These results of this study showed that PGPR could be helpful to mitigate the salinity stress of different plants at the time of germination.