Temperature and salinity significantly affect seed germination, but the joint effects of temperature and salinity on seed germination are still unclear. To explore such effects, a controlled ...experiment was conducted, where three temperature levels (i.e., 15, 20, and 25°C) and five salinity levels (i.e., 0, 25, 50, 100, and 200 mmol/L) were crossed, resulting in 15 treatments (i.e., 3 temperature levels × 5 salinity levels). Three typical grass species (
,
, and
) were used, and 25 seeds of each species were sown in petri dishes under these treatments. Germination percentages and germination rates were calculated on the basis of the daily recorded germinated seed numbers of each species. Results showed that temperature and salinity significantly affected seed germination percentage and germination rate, which differed among species. Specifically,
had the highest germination percentage, followed by
and
, with a similar pattern also found regarding the accumulated germination rate and daily germination rate. Generally,
was not sensitive to temperature within the range of 15-25°C, while the intermediate temperature level improved the germination percentage of
, and the highest temperature level benefited the germination percentage of
. Moreover,
was also not sensitive to salinity within the range of 0-200 mmol/L, whereas high salinity levels significantly decreased the germination percentage of
and
. Thus, temperature and salinity can jointly affect seed germination, but these differ among plant species. These results can improve our understanding of seed germination in saline soils in the face of climate change.
Proper and uniform seed depth within the optimum range increases crop germination rate, which directly affects yield. Seed depth mainly depends on seed placement techniques. In conventional seed ...drill and planters, variations and fluctuations in seeding depth were recorded. This issue can be resolved by adaption of intelligent crop sowing machinery. A real-time seed depth control system was designed and developed to monitor and maintain the required seed depth. The developed system was installed on a tractor-mounted conventional seed drill. The materials used were ultrasonic sensors, a micro-controller, an RTC module, buzzers, an LCD, an SD card module, a power battery, and switch buttons. The system read height difference as a reference value. The seeding depth data was stored in the SD card. The results showed by introducing real time depth control system in existing seeders, it is possible to achieve desired plant population and homogeneous germination. The average cumulative germination rate (GR) of wheat with the seed depth control system was 126 plants/m2, and with a conventional seed drill (without SDCS) 117 plants/m2. The yield of wheat with the seed depth control system was 1225 kg/acre, and with the conventional seed drill (without SDCS) 1124 kg/acre in an arid region. Result shows that the crop yield could be enhanced by proper seed placement at the required seed depth by using the seed depth control system. Further field trials on different soils, regions and environmental conditions could improve the results.
Nitrogen fixation is crucial for plants as it is utilized for the biosynthesis of almost all biomolecules. Most of our atmosphere consists of nitrogen, but plants cannot straightforwardly assimilate ...this from the air, and natural nitrogen fixation is inadequate to meet the extreme necessities of global nutrition. In this study, nitrogen fixation in water was achieved by an AC-driven non-thermal atmospheric pressure nitrogen plasma jet. In addition, Mg, Al, or Zn was immersed in the water, which neutralized the plasma-treated water and increased the rate of nitrogen reduction to ammonia due to the additional hydrogen generated by the reaction between the plasma-generated acid and metal. The effect of the plasma-activated water, with and without metal ions, on germination and growth in corn plants (
) was investigated. The germination rate was found to be higher with plasma-treated water and more efficient in the presence of metal ions. Stem lengths and germination rates were significantly increased with respect to those produced by DI water irrigation. The plants responded to the abundance of nitrogen by producing intensely green leaves because of their increased chlorophyll and protein contents. Based on this report, non-thermal plasma reactors could be used to substantially enhance seed germination and seedling growth.
Clubroot caused by the obligate biotrophic parasite
is a destructive soil borne disease of cruciferous crops. Resting spores of
can survive in the soil for a long period without hosts or external ...stimulants. The viability and germination rate of resting spores are crucial factors of the inoculum potential in the field. The accurate assessment of viability and germination rate is the foundation to evaluate the effect of control methods. In this study, we evaluated several methods for the assessment of viability and germination rate of
resting spores. Dual staining with calcofluor white-propidium iodide (CFW-PI) or single stain with Evans blue showed reliable accuracy in estimating viability. CFW-PI was capable of reliably determining the viability within 10 min, while Evans blue required overnight incubation to obtain accurate results. Due to DNA degradation of heat treatments, acetone was selected to evaluate the efficiency of propidium monoazide (PMA)-quantitative PCR (qPCR) used for the quantification of DNA from viable cells. The staining with 4,6-Diamidine-2-phenylindole dihydrochloride (DAPI) and the use of differential interference contrast microscopy were suitable for the determination of resting spore germination rates. The latter method also allowed recording individual germination states of spores. Alternatively, dual staining with CFW-Nile red was successfully used to assess the germination rate of resting spores with a lethal pre-treatment. This study evaluates and confirms the suitability of various microscopic and molecular genetic methods for the determination of viability and germination of
resting spores. Such methods are required to study factors in the soil regulating survival, dormancy and germination of
resting spores causing clubroot disease in Brassicaceae hosts and therefore are fundamental to develop novel strategies of control.
Food production and boosting its productivity is the major challenge across the word. Nanoparticles can affect the growth, germination rate and development of plants. Silver sulphide (Ag2S NPs), zinc ...sulphide nanoparticles (ZnS NPs) and their composite (Ag2S–ZnS NCs) in powder form has been synthesised by chemical precipitation method using silver nitrate and zinc acetate with sodium sulphide (Na2S). The morphology, structure, size and purity of synthesised metal sulphide nanoparticles and nanocomposites were confirmed by UV–visible, Energy Dispersive Analysis of X-ray (EDX), Scanning Electron Microscopy (SEM) and X-ray powder diffraction (XRD). The optical energy band gap for Ag2S NPs was 3.25eV, for ZnS NPs 4.85eV and 5.4 eV for Ag2S–ZnS NC as investigated by UV–visible. The peaks in EDX spectrum confirmed the composition of material formation and purity of Ag2S NPs, ZnS NPs and Ag2S–ZnS NCs. Seeds of soybean and wheat were sowed in petri dishes in suspension of Ag2S NPs, ZnS NPs and Ag2S–ZnS NCs separately with various concentrations of NPs. The effect of various concentration of metal sulphide NPs and NCs on different parameter of germination has been studied. Experiments revealed that application of metal sulphide NPs and NCs can help to enhance the germination, root and shoot length and mean germination time (MGT) as compared to control treatment. It was found that suitable small time soaking favours good germination. Ag2S–ZnS NCs increases germinability, supress germination rate, elongates root and shoot length and reduce MGT significantly.
•Ag2S NPs, ZnS NPs and their composite in powder form has been synthesised by chemical precipitation method.•Enhancement in germination rate of soybean and wheat seeds with Ag2S, ZnS as well as Ag2S–ZnS coating.•The soaking time also proved as significant for % germinability of wheat and soybean.•Ag2S–ZnS NPs are very useful for improving root and shoot length for wheat seeds.
Superheated steam (SHS) is a powerful technology used to reduce bacteria on food surfaces while causing less damage to the underlying sublayer of food compared to conventional heating treatments. In ...this study, a semi-continuous SHS system was developed to inactivate foodborne pathogens within 1 s (Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes) on radish seed surfaces and to enhance the seeds’ salinity tolerance, which is vital for adapting to arid and semi-arid regions. The temperature of the SHS was set to 200 °C and 300 °C, with flow rates of 5 m/s and 7 m/s, and treatments were cycled either once or three times. As a result, increased temperature (200 °C–300 °C) and number of treatments (1 time to 3 times) led to a significantly larger microbial reduction on the surface of radish seeds. E. coli O157:H7, S. enterica, and L. monocytogenes were reduced by 4.42, 4.73, and 3.95 log CFU/g (P < 0.05), respectively, after three SHS treatments at 300 °C and 7 m/s. However, due to the ongoing potential for recovery of residual microorganisms, further research involving combinations is essential to enhance the microbicidal effect. Water imbibition showed significantly higher values in the SHS-treated group up to 30 min, indicating faster germination rates in the SHS-treated group (71.3–81.3%) compared to the control group (52.7%) on the second day, indicating a significant enhancement in germination rate. In addition, the salinity resistance of the radish seeds increased after SHS treatment. When moisturized with 0.5% NaCl solution, more radish seeds germinated after treatment with SHS (40%) than controls (22.7%) (P < 0.05). The results of this study, the first to apply semi-continuous SHS to seeds, are expected to serve as a cornerstone for future pilot-scale investigations aiming to implement the system within the seed industry.
•Semi-continuous SHS at 300 °C ensures biological safety by achieving over 3 log-reduction of pathogens on radish seeds.•Microbicidal effects of SHS are enhanced by higher fluid velocity and repeated treatment cycles.•Semi-continuous SHS system breaks seed dormancy, leading to improved water uptake, germination, and salinity tolerance.•The increased salinity tolerance will be beneficial when sprouting seeds using irrigation water, especially in arid regions.
Soil salinity is a major limiting factor for agricultural production, threatening food security worldwide. A thorough understanding of the mechanisms underlying plant responses is required to ...effectively counter its deleterious effects on crop productivity. Total flavonoid accumulation reportedly improves salinity tolerance in many crops. Therefore, we isolated the full-length cDNA of a flavonol synthetase (FLS) gene from Apocynum venetum (AvFLS). The gene contained a 1008-bp open reading frame encoding a protein composed of 335 amino acid residues. Multiple sequence alignment showed that the AvFLS protein was highly homologous to FLSs from other plants. AvFLS was expressed in leaves, stems, roots, flowers, and germinated seeds. Expression pattern analysis revealed that AvFLS was significantly induced by salinity stress. AvFLS overexpression in tobacco positively affected the development and growth of transgenic plants under salinity stress: root and seedling growth were inhibited to a lesser extent, while seed germination rate increased. Additionally, the overexpression of AvFLS under salinity stress resulted in an increase in total flavonoid content (1.63 mg g−1 in wild-type samples and 4.63 mg g−1 on average in transgenic samples), which accompanied the increase in the activity of antioxidant enzymes and inhibited the production of reactive oxygen species. Further, AvFLS-overexpressing transgenic tobacco plants absorbed more K+ than wild type plants, leading to an increased K+/Na+ ratio, which in turn contributed to the maintenance of Na+/K+ homeostasis. These findings suggest that an AvFLS-induced increase in total flavonoid content enhanced plant salinity tolerance, implying the importance of AvFLS gene responses to salinity stress.
•A cDNA encoding flavonol synthetase from A. venetum was isolated and characterized.•Expression patterns of the AvFLS gene in response to salinity were identified.•AvFLS-overexpressing tobacco plants accumulated more flavonoids than the WT.•Accumulation of flavonoids attenuated oxidative damage and allowed growth recovery.•AvFLS-overexpressing tobacco plants maintained K+/Na+ homeostasis under salinity.
•The LLE algorithm was improved and applied to maize germination rate detection.•The model results of different improvement strategies of LLE are studied and compared.•The cosine similarity is ...suitable as a distance metric for NIR spectral data.•This study can provide a reference method for other agricultural products quality testing.
Locally linear embedding (LLE) is a nonlinear dimensionality reduction method, which has great advantages over linear dimensionality reduction methods. However, the traditional LLE takes the Euclidean distance as the distance measure, which is difficult to accurately reflect the spatial position relationship between the high-dimensional data of the near-infrared spectrum, resulting in a poor modeling effect. This paper tries to improve the LLE with different distance metric methods and proposes a rapid detection method for maize seed germination rate based on improved local linear embedding and near-infrared spectroscopy. In this paper, a total of 315 samples from 7 different types of maize seeds, purchased from the seed market, were adopted as the research object. We performed artificial aging tests with 8 different gradients (from 0d to 7d with interval of 1d) on them and completed the germination rate test after collecting the near-infrared spectral data for each sample. The Monte Carlo cross-validation (MCCV) algorithm, combined with PLSR and SVM, was used to remove abnormal samples from the spectral and germination rate data. And then, for comparison, we used several different improvement strategies for LLE (traditional Euclidean distance, Manhattan distance, Chebyshev distance, Correlation coefficient, and Cosine similarity) to reduce the spectral data dimension and established PLS and SVM germination rate prediction models. We compared the prediction effects of different models to explore the optimal improvement strategy of LLE dimension reduction distance measurement. The results showed that the cosine similarity was the best improvement strategy under the same modeling method. The R2 of the LLE_ cos-PLS model's test set can reach 0.8384, and the R2 of the LLE_cos-SVM model's test set can reach 0.8765. The results showed that the cosine similarity could better reflect the spatial distribution in the spectral data of aged maize seeds, and the precision of the model was higher after LLE_cos dimensionality reduction. Compared with the linear modeling method PLS, the nonlinear modeling method SVM is more suitable for predicting the germination rate of maize seeds. This study can provide a reference method for the quality inspection of other agricultural products.
•The trend of germination of safflower seeds to different temperatures and water potentials was described.•The best function describing the relationship of germination rate of safflower seeds to both ...temperature and water potential was selected.•The cardinal temperatures and physiological hours for germination using the superior function were determined.•We determined the base water potential (Ψb), the hydrotime constant (θH), the thermal time constant (θT) and hydrothermal time constant (θHT) of safflower germination.
Seed germination, a physiological process, experiences large deviations based on temperature and water potential. Each factor can, separately or jointly, affect the germination percentage and germination rate. The response of plant growth rate (including germination rate) to both temperature and water potential can be described as a non-linear function of the thermal time, hydrotime, and the hydrothermal time models. We compared 3 non-linear regression models (Dent-like, segmented and beta) and thermal time, hydrotime and hydrothermal time models to describe the germination rate temperature and water potential relationships of safflower (Carthamus tinctorius L.). An investigation on an experiment for the joint effect of nine constant temperature regimes (5, 10, 15, 20, 25, 30, 35, 40 and 45 °C) and nine water potential values (0, −0.2, −0.4, −0.6, −0.8, −1, −1.2, −1.4 and −1.6 MPa) on safflower seed germination (SSG) was conducted. The outcome revealed that the segmented function (RMSE = 0.28, R2 = 0.82 and r = 0.90) was suitable for use in describing SSG response to temperature and water potential. Using this function, the base, optimum and ceiling emergence temperature and the physiological hour were estimated to be 3.9, 39.3 and 45 °C, and 5.7 h respectively. The hydrotime constant for SSG (θH), the middle value for the base water potential (Ψb(50)), the standard deviation in the water potential (σyb) and the thermal time constant for SSG (θT) spanned the values of 2.54–137.1 MPa h, −1.68–0.06 MPa, 0.32–0.72 MPa and 308.1–3963.1 °C h, respectively. The hydrothermal time parameters were 379.7 MPa °C h, −1.28 MPa and 3.10 °C for θHT (hydrothermal time constant), and Ψb(50) (median base water potential), Tb (base temperature) in temperatures and water potentials, respectively. All model parameters may be readily used in safflower simulation models.
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