Seedling Stem Research Articles

Foliar Application of Abscisic Acid Alleviates Cadmium Stress by Modulating Differential Physiological and Transcriptome Response in Leaves, Stems, and Roots of Mung Bean Seedlings

Foliar Application of Abscisic Acid Alleviates Cadmium Stress by Modulating Differential Physiological and Transcriptome Response in Leaves, Stems, and Roots of Mung Bean Seedlings

A Precise Segmentation Algorithm of Pumpkin Seedling Point Cloud Stem Based on CPHNet.

Accurate segmentation of the stem of pumpkin seedlings has a great influence on the modernization of pumpkin cultivation, and can provide detailed data support for the growth of pumpkin plants. We collected and constructed a pumpkin seedling point cloud dataset for the first time. Potting soil and wall background in point cloud data often interfere with the accuracy of partial cutting of pumpkin seedling stems. The stem shape of pumpkin seedlings varies due to other environmental factors during the growing stage. The stem of the pumpkin seedling is closely connected with the potting soil and leaves, and the boundary of the stem is easily blurred. These problems bring challenges to the accurate segmentation of pumpkin seedling point cloud stems. In this paper, an accurate segmentation algorithm for pumpkin seedling point cloud stems based on CPHNet is proposed. First, a channel residual attention multilayer perceptron (CRA-MLP) module is proposed, which suppresses background interference such as soil. Second, a position-enhanced self-attention (PESA) mechanism is proposed, enabling the model to adapt to diverse morphologies of pumpkin seedling point cloud data stems. Finally, a hybrid loss function of cross entropy loss and dice loss (HCE-Dice Loss) is proposed to address the issue of fuzzy stem boundaries. The experimental results show that CPHNet achieves a 90.4% average cross-to-merge ratio (mIoU), 93.1% average accuracy (mP), 95.6% average recall rate (mR), 94.4% F1 score (mF1) and 0.03 plants/second (speed) on the self-built dataset. Compared with other popular segmentation models, this model is more accurate and stable for cutting the stem part of the pumpkin seedling point cloud.

A deep learning-based method for estimating the main stem length of sweet potato seedlings

The length of sweet potato seedling main stems is critical for harvest decisions, but accurately measuring it is challenging due to leaf occlusion and self-curvature. This study proposes a method for stem reconstruction and length estimation using a two-stage classifier, feature extraction, and semantic segmentation to obtain stem masks. Image processing separates clustered skeletons into singular lines for detailed analysis. Object detection identifies roots, stem-leaf intersections, and establishes a search relationship among segments. Stems are reconstructed based on directional, distance, and curvature constraints, then divided into four parts for length estimation using stereo depth information. Experimental results demonstrate effectiveness under various conditions: un-occluded, partially occluded, curved stems, and low-density clusters. Median length estimation error is 1.7 cm, with maximum and minimum errors of 3.2 cm and 0.3 cm respectively. This automated method provides a reliable solution for sweet potato seedling harvest and grading.

Pythium aphanidermatum causing seedling damping-off of Hylocereus megalanthus in China.

Hylocereus megalanthus (family Cactaceae), commonly known as bird's nest fruit (Yanwo fruit), was a new tropical plant cultivated commercially in south China because of its high nutritional content and sweet taste. In August 2023, damping-off disease of approximately 60% of seedlings was observed at a nursery in Zhanjiang, Guangdong Province (E110°17'46″ N21°9'2″). Stems of infected seedlings exhibited symptoms of water-soaked tissue which caused collapse at the base of the stem and sloughing of necrotic root cortex tissue was observed (Figure 1). White aerial mycelia were visible on the surface of the stem and soil at a high relative humidity. Diseased tissues about 0.5 cm2 were taken from the infected roots and stems, surface disinfected with 75% ethanol and 3% hydrogen peroxide solution, each for 1 min, subsequently rinsed in sterile water, and placed on potato dextrose agar (PDA). Plates were incubated at 25 to 28℃ in the dark for 3 days. Coenocytic hyphae grew from all infected roots and stems. Hyphal tip transfers were completed twice, and twelve isolates with the same morphological characteristics were obtained. The colony growth on PDA was ample. Main hyphae are up to 9.5 µm wide. Sporangia were terminal, inflated, branched or unbranched. Encysted zoospores were 7.5 µm in diameter. Oogonia were terminal, globose, smooth and of 16.8 to 27.4 µm (average 21.5 µm) diameter. Oospores were typically spherical, thick-walled, yellowish, 19.7 to 26.3 µm (average 21.1 µm) diameter, wall 1 to 2 µm thick. Antheridia were mostly intercalary, sometimes terminal, broadly sac-shaped, 15.0×19.0 µm (Figure 2). The morphological features were very similar to those of Pythium spp. (Toporek and Keinath 2021). For further identification, the LSU and ITS regions of isolate CCAS-YWGCD (stored in Agricultural Culture Collection of China, ACCC 35633) were amplified and sequenced with using primer pairs LROR/LR7 and ITS1/ITS4, respectively (Gao et al. 2017; White et al. 1990). The resulting sequences were deposited in GenBank (ITS: OR775664; LSU: OR775667). BLASTn results showed 100% sequence similarity with reference sequences of Pythium aphanidermatum (AY598622 for ITS and HQ665084 for LSU). Phylogenetic tree generated from maximum likelihood analysis based on combined LSU and ITS sequence data with MEGA 10.1.8, clustered the oomycete in P. aphanidermatum clade with 100% bootstrap support (Figure 3). Therefore, the oomycete was identified as P. aphanidermatum. To confirm Koch's postulates, six three-month-old seedlings of H. megalanthus (height about 15 cm) were transplanted to 15 cm pots. Six-mm-diameter mycelial plugs obtained from 7-day-old cultures at 25℃ in the dark were buried adjacent to the stem of three unwounded healthy seedlings. Another three seedlings inoculated with PDA agar served as controls. The plants were covered with plastic bags, kept at about 30℃, and watered regularly to keep the soil moisture content high. All inoculated seedlings exhibited symptoms of stems rot and damping-off, Symptoms did not develop on the control seedlings. P. aphanidermatum by morphological and molecular analysis was reisolated from the stems. P. aphanidermatum had been reported worldwide causing disease in many agricultural crops (Qi et al. 2021; Kim et al. 2020), but this is the first report causing damping-off of H. megalanthus seedling in China as well as worldwide, and this disease should be monitored in nursery seedlings.

Enhancing Seed Germination and Seedlings Growth of Khao Dawk Mali 105 Rice Cultivar via Seed Coating and Infrared Drying Apparatus

Seed coating techniques had emerged as a promising approach for precise planting and safeguarding crops against environmental stresses. Simultaneously, infrared drying, renowned for its cost-effectiveness and efficiency, held promises for enhancing the quality of drying processes. This investigation delved into the procedures applied to Khao Dawk Mali 105 rice seeds during the coating and drying process using a prototype of the hexagonal drum. The results found that the drying temperature (factor B) and duration of drying time (factor C) had substantial primary effects (p ≤ 0.05), while the drum rotational speed (factor A) did not exert a noteworthy influence. Additionally, meaningful interactions were observed among the factors AB, AC, BC, and ABC. Impressively, it resulted in germination rates of 80.56 and 80.25 %, coupled with germination indices of 84.88 and 85.47 %, when utilizing a drum speed of 20 rpm, a drying temperature of 45 °C, and a drying time of 8 min (R-204508), and a drum speed of 10 rpm, a drying temperature of 45 °C, and a drying time of 8 min (R-104508), respectively. Additionally, the mean germination time amounted to 9.64 days, and the length of the rice seedling stem reached 13.66 cm when employing a drum speed of 20 rpm, a drying temperature of 50 °C, and a drying time of 8 min (R-205008). These discoveries emphasized the potential of the prototype's seed coating and infrared drying technology integration to improve rice germination and subsequent growth. This enhancement could ultimately result in higher yields and increased productivity, especially in small-scale agricultural settings. HIGHLIGHTS These discoveries emphasized the potential of the prototype's seed coating and infrared drying technology integration to improve rice germination and subsequent growth. This enhancement could ultimately result in higher yields and increased productivity, especially in small-scale agricultural settings. Ensuring precise control over drying temperature and duration is of paramount importance in establishing optimal and consistent conditions for the germination and subsequent growth of rice seeds, thereby augmenting plant vigor and overall yield The investigation determined optimal coating and drying conditions, encompassing a drum speed of 20 rpm, a drying temperature of 45 °C, and a drying duration of 8 min (treatment R-204508), along with a drum speed of 20 rpm, a drying temperature of 45 °C, and a drying time of 8 min (treatment R-104508). These conditions resulted in the highest mean germination rates and germination indices. GRAPHICAL ABSTRACT

The Effect of Gamal Leaf Liquid Organic Fertilizer on the Growth of Arabica Coffee (Coffea Arabica L.) Seedlings in Polybags

This research was carried out for 3 months, namely from March 2023 to June 2023, located at the BPDAS-HL Palu-Poso Permanent Nursery, this study used the Complete Randomized Design method consisting of 4 treatments, namely P0 = 0%, P1 = 20%, P2 = 30% and P3 = 30%. The four treatments were repeated seven times, bringing the total sample to 28 experimental units. The parameters observed are the increase in seedling height, stem diameter and number of leaves. The data analysis used is fingerprint analysis (F test) fingerprint analysis shows that the best treatment, it will be continued with further tests, namely the BNJ test level of 5%. The results showed that the concentration treatment of liquid organic fertilizer made from gamal leaves had a real influence on the increase in height, stem diameter and number of leaves in arabica coffee seedlings. The best treatment in this study was 40% concentration treatment (P3) with an average seedling height of 15.27 cm, an average seedling stem diameter of 3.17 mm and an average number of seedling leaves of 12.28 strands and the results of BNJ fingerprint analysis with an average height of 5.59 cm, number of leaves of 1.2 strands and stem diameter of 0.88 mm.

GmABCG5, an ATP-binding cassette G transporter gene, is involved in the iron deficiency response in soybean.

Iron deficiency is a major nutritional problem causing iron deficiency chlorosis (IDC) and yield reduction in soybean, one of the most important crops. The ATP-binding cassette G subfamily plays a crucial role in substance transportation in plants. In this study, we cloned the GmABCG5 gene from soybean and verified its role in Fe homeostasis. Analysis showed that GmABCG5 belongs to the ABCG subfamily and is subcellularly localized at the cell membrane. From high to low, GmABCG5 expression was found in the stem, root, and leaf of young soybean seedlings, and the order of expression was flower, pod, seed stem, root, and leaf in mature soybean plants. The GUS assay and qRT-PCR results showed that the GmABCG5 expression was significantly induced by iron deficiency in the leaf. We obtained the GmABCG5 overexpressed and inhibitory expressed soybean hairyroot complexes. Overexpression of GmABCG5 promoted, and inhibition of GmABCG5 retarded the growth of soybean hairy roots, independent of nutrient iron conditions, confirming the growth-promotion function of GmABCG5. Iron deficiency has a negative effect on the growth of soybean complexes, which was more obvious in the GmABCG5 inhibition complexes. The chlorophyll content was increased in the GmABCG5 overexpression complexes and decreased in the GmABCG5 inhibition complexes. Iron deficiency treatment widened the gap in the chlorophyll contents. FCR activity was induced by iron deficiency and showed an extraordinary increase in the GmABCG5 overexpression complexes, accompanied by the greatest Fe accumulation. Antioxidant capacity was enhanced when GmABCG5 was overexpressed and reduced when GmABCG5 was inhibited under iron deficiency. These results showed that the response mechanism to iron deficiency is more actively mobilized in GmABCG5 overexpression seedlings. Our results indicated that GmABCG5 could improve the plant's tolerance to iron deficiency, suggesting that GmABCG5 might have the function of Fe mobilization, redistribution, and/or secretion of Fe substances in plants. The findings provide new insights into the ABCG subfamily genes in the regulation of iron homeostasis in plants.

Diâmetro do caule para enxertia do tomate italiano

ABSTRACT The adoption of grafting in vegetable production is an innovative technique that presents challenges to be overcome, which one of the main ones is the need to determine the appropriate diameter of the plant at the time of grafting. Therefore, the objective of this work was to evaluate the development of seedlings and production of tomato plants, grafted with different stem diameters, under protected environmental conditions. The experiment was divided into two phases, seedling development and field production. The experimental design was completely randomized with five treatments, composed of the following seedlings stem diameters at the time of grafting: 1.8; 2.0; 2.2; 2.5 and 2.8 mm. Morphophysiological and productive characteristics of the grafted plants were evaluated. The results demonstrated that Italian tomato seedlings, grafted with 2.2 mm stem diameter, showed better development. However, the production rates were similar for the different stem diameters (1.8 to 2.8 mm) adopted at the grafting moment. Estimated yields of around 200 t/ha, much higher than the national average, demonstrate the success of the grafting technique in Italian tomatoes, under protected environmental conditions.

BIOTESTING OF SOIL CONDITIONS AT THE TERRITORIES ADJACENT TO AIRPORTS

The development of civil aviation is accompanied by a constant increase in man-made load on the environment. The application of methods of bioindication and biotesting of anthropogenic and technogenic influences on the ecosystem components is one of the possible options for monitoring the state of the environment at territories subject to technogenic stress due to the activities of environmentally hazardous enterprises. To study the level of man-made impact of airport activities on the state of the soil (namely, phytotoxicity), at the territory adjacent to the airport "Kyiv" named after I. Sikorskyi International Airport from the upper and lower levels at different distances from the airport runway (from 5 m to 2 km) soil samples were taken using the envelope method. As a control (conditionally clean soil), a soil sample collected at the territory of Holosiiv Park (soil type: dark gray forest soils) was used. In total, six soil samples were analyzed. On the third day of germination the growth characteristics of Allium cepa seedlings were determined. Test parameters that were used to determine the phytotoxic effect: the percentage of seed germination, namely the energy of its germination, the length of the root and the length of the stem. The analysis of the obtained data on the germination of Allium cepa seeds showed that the lowest germination was recorded for the soil samples that were taken at a distance of 5 and 1500 m from the runway, which indicates an increased level of phytotoxic impact due to the activities of the airport.
 The greatest phytotoxic effect for the stem of Allium cepa seedlings was observed for the soil sample located at a distance of 5 m from the ZPS. For soil samples taken at a distance of 5 m to 1000 m, i.e. with distance from the runway of the airport, a decrease in the level of phytotoxicity of the soil is observed. Only when approaching the highway (at a distance of 1,000 m to 2,000 m) there was observed an increase in phytotoxicity of the soil again.
 Among the investigated samples of meristem tissues, the presence of mitotic activity of cells was observed in the meristems of root tip samples of onion seedlings germinated on soil samples that were taken at a distance of 5 m, 1500 m and 2000 m from the airport. The determined mitotic indices (MI) for these soil samples are as following: for a soil sample taken at a distance of 5 m, it was 2.9 %; for a soil sample taken at a distance of 1500 m was 2.6 %; for a soil sample taken at a distance of 2000 m was 2.6 %. The research results confirm the need for constant monitoring of the soil condition at these technogenically loaded territories, in order to increase the level of environmental safety of these territories.

Stem cutting: A novel introduction site for transporting water-insoluble particles into tomato (Solanum lycopersicum) seedlings

The introduction of exogenous particles into plants has promising applications in agriculture and biotechnology. Nanoparticles can be transported into plants through foliar application or root uptake. However, both methods have limitations in terms of the size of the particles (<40 nm) that can be transported due to the barriers of the cell wall and cuticle. In the present study, we proposed a novel method to deliver particles of up to 110 nm into plants by cutting the stem of tomato seedlings. We demonstrated for the first time, using water-insoluble silica colloids, that not only nanoparticles but also submicron particles can be transported toward the leaves when the plant stem is used as the entry point of particles. Thirty-five-day-old tomato seedlings were used as the target plants. When the cut stem seedlings were immersed in the colloidal particle suspension for up to 24 h, significant particle accumulation was observed in the nodes and leaves. The relatively low particle concentrations (10 mg/L) allowed effective transport throughout the plants. Silica particles with average diameters of 10 nm and 110 nm were both well transported and moved through the stem. Even after the particles entered the plant, adventitious roots were formed, resulting in the formation of whole plants with roots, stems, and leaves. This method can be applied not only to tomatoes but also to other food crops for various applications in plant biotechnology.

Effects of Phosphorus Deficiency on Ion Transport And Its Anatomical Relation in Mung Bean (Vigna Radiata L.)

Effects of phosphorus deficiency on ion transport and its relation with anatomical structure in mungbean plants were investigated. Phosphorous deficiency caused an increase in the accumulation of K+ in the root and a decrease in the stem and leaf of mungbean seedlings grown in solution culture. Na+ and NO3 - accumulation was increased in the root, stem and leaf of P-deficient plant. On the contrary, accumulation of PO4 3- was decreased in root, stem and leaf under P-deficiency treatment. The diameter of root was decreased under phosphorus deficiency. Vascular area was found to decrease and occupied less area with smaller size of metaxylem cavity in the root and stem of mungbean plant. In phosphorus deficient plant, phloem elements were poorly developed and occupied smaller area. Bangladesh J. Bot. 52(2): 381-387, 2023 (June)

Effects of Airflow Disturbance on the Content of Biochemical Components and Mechanical Properties of Cucumber Seedling Stems

In order to explore the changes in biochemical components and mechanical properties of cucumber seedlings with dwarfing characteristics under airflow disturbance treatment, ‘Jinyou No. 1’ cucumber seedlings were used as experimental materials and the split-plot design was used. The cucumber seedlings were treated with airflow disturbance with two airflow temperatures of 25 ± 5 °C and 35 ± 5 °C as the main factors and four airflow velocities of 1, 3, 6 and 9 m/s as the secondary factors. At the same time, cucumber seedlings without airflow disturbance were used as controls to study the effects of airflow temperature and velocity on the biochemical components and mechanical properties of cucumber seedling stems. The results showed that with the increase in airflow velocity, the content of the stems’ biochemical components increased to varying degrees, and the bending load, shear load, elastic modulus, bending strength and shear strength of the seedling stems also increased. Under the same airflow velocity, the biochemical component content and the accepted load of seedlings under the 25 ± 5 °C airflow temperature treatment were larger than those under the 35 ± 5 °C airflow greenhouse treatment, but the elastic modulus, bending strength and shear strength of seedlings under the 25 ± 5 °C airflow temperature treatment were lesser than those under the 35 ± 5 °C airflow temperature treatment. Using the grey relational analysis method, the correlation degree between the biochemical components of the stem and the mechanical properties of the stem was different. The correlation degree between the biochemical components of the seedling stem and the mechanical properties under different airflow temperature treatments was significant. The correlation degree between the biochemical components of the seedling stem and the mechanical properties under different airflow velocity treatments was greater than 0.60, indicating that the biochemical components of the seedling stem under airflow velocity treatments had a greater influence on the mechanical properties. In summary, airflow disturbance significantly affected the biochemical components and mechanical properties of cucumber seedlings. The biochemical components and mechanical properties of seedlings were negatively correlated with airflow temperature and positively correlated with airflow velocity. With a decrease in airflow temperature and an increase in airflow velocity, the biochemical components and mechanical properties of seedlings increased.

First report of seedling stem blight of mango caused by Neofusicoccum parvum in Italy.

Seedling blight of mango (Mangifera indica L.) was observed in a commercial nursery located in Messina province (eastern Sicily, Italy) during winter of 2021. More than 30% of 3,000 seedlings, about three to six months old, of mango cv. Gomera 3 showed symptoms of basal stem blight. The symptoms started from seed, led to the decline and subsequent death of the plants. Necrotic lesions appeared at crown level two months after sowing. The stem tissues of ten symptomatic plants were cut, surface sterilized, dipped in 1.5% sodium hypochlorite for 1 min and transferred onto potato dextrose agar medium (PDA) and incubated at 25°C for four days. Approximately 60% of stem tissues developed very similar fungal colonies, resembling to Botryosphaeriaceae. A total of four representative isolates were collected through single hyphal-tip and stored at 4 °C. The internal transcriber spacer region (ITS) was amplified with primers, ITS5/ITS4 (White et al., 1990), and EF1-728F and EF1-986R (Carbone and Kohn, 1999) were used to amplify part of the translation elongation factor 1alpha gene (tef1-α), and primers Bt2a/Bt2b (Glass and Donaldson, 1995) were used for the partial β-tubulin (tub2). The obtained sequences were deposited in GenBank with accession numbers: ON911292-95 for the ITS, ON933621-24 for tef1-α and ON933625-28 for tub2.To compare the results, 50 additional sequences were selected and inserted in the alignment according to the recent literature on the Botryosphaeriaceae (Bezerra et al., 2021; Zhang et al., 2021). Maximum parsimony analysis (MP) of concatenated dataset (ITS + tef1-α + tub2) was performed in PAUP v.4.0a. Clade support was assessed by 1,000 bootstrap replicates and Botryosphaeria dothidea was used as an outgroup. Our isolates clustered within the group of Neofusicoccum parvum (71% bootstrap value) (ex-type CMW9081). Based on these results, and morphological data (50 conidia length × width average: 18.1 × 6.6, respectively) our isolates (named MC) were identified and confirmed as Neofusicoccum parvum (Pennycook & Samuels) Crous, Slippers & A.J.L. Phillips. Pathogenicity tests were also conducted on 18 mango cv. Gomera 3 seedlings. The crown roots of each seedling were mechanically wounded and a mycelial plug of the isolate MC14 was placed onto them and covered with soil. Controls (three seedlings) were inoculated with sterile PDA only. Seedlings were maintained in a growth chamber with a 12 hrs photoperiod at 25°C ± 1°C and watered regularly. After five days, stem lesions appeared externally (1.6 cm) and one month after the inoculation, all the inoculated seedlings died. However, controls did not show any obvious symptoms. Re-isolations were conducted as described above and fulfilled Koch's postulates confirming pathogenicity. Among the diseases affecting mango plants, Botryosphaeriaceae represent a serious threat in Sicily as reported by Aiello et al., 2022. The endophytic behaviour of Botryosphaeriaceae is well known, making them latent pathogens (Slippers and Wingfield, 2007). In Italy, N. parvum was detected in mango orchards since 2013 (Ismail et al. 2013), but symptoms of seedlings stem blight have never been reported in the nursery. In Sicily, an increase of Botryosphaeriaceae infection has been observed recently, especially in nurseries, where N. parvum has been identified as a most destructive pathogen (Aiello et al., 2020; Gusella et al., 2021). To our knowledge, this is the first report worldwide of N. parvum causing mango seedling blight. The high incidence of infected seedlings detected in this study highlights the potential risk during propagation in the nursery, representing a significant source of inoculum for the field.

Characterization of fluorescence properties of wounds on soybean seedlings during healing process using excitation emission matrix and fluorescence imaging

To establish a simple and nondestructive method for measuring plant wound-healing ability, we characterized the fluorescence characteristics of wounds on hypocotyl of soybean seedlings during healing process. Wounds were manually created on the stem of soybean seedlings 7 days after sowing. The fluorescence time-series characteristics of the wounds were measured until 96 h after wounding using excitation emission matrix (EEM) and fluorescence images excited by wavelength of 365 nm. In the EEM of wounds, three main fluorescence peaks were observed, and the intensity decreased with time after wounding. The reddish color due to chlorophyll in fluorescence images also decreased with healing process. In addition, microscopic observation of the wounded tissue using a confocal laser microscope showed that the intensity of lignin or suberin like fluorescence increased with healing time, which might have blocked the excitation light. These results suggest that UV-excited fluorescence can be a new indicator of the healing ability of plant tissues.

Scientific-based regime of irrigation of raspberry with dripping irrigation under the conditions of the Central Non-Black Earth Region

Raspberries are among the important berry crops, the production volumes of which are increasing every year. To obtain high-quality planting material, high and stable yields in unstable weather conditions, it is necessary to develop resource-saving technologies, which include drip irrigation. The purpose of the research is to develop a science-based irrigation regime for drip irrigation of raspberries in the conditions of the Central region of the Non-Chernozem zone of Russia. A two-factor field experiment was established in the fall of 2019. The first factor is the drip irrigation regime (maintaining the moisture content of the root layer of the soil in the ranges of 60…80, 70…90 and 80…100% of the lowest moisture capacity), the second factor is the variety (Nagrada and Solnyshko). Drip irrigation of raspberries can significantly save irrigation water. In the variant of drip irrigation with maintaining moisture in the root layer in the range of 80…100% of the lowest moisture capacity, the savings in irrigation water compared to traditional irrigation methods averaged 65%, and in the variant of 60-80% of the lowest moisture capacity - 78%. At the same time, with the use of local irrigation, an optimal water-air regime of the soil is created. For the irrigated variants of the experiment, the main share in the total water consumption is precipitation (from 71 to 81%), and the irrigation rate - from 15 to 22%. In the variants with maintaining humidity above 70% of the lowest moisture capacity, the diameter of the stem of seedlings is 20-40% larger than in the control, the height of seedlings is 40-50%, and the yield is 2 times, which makes it possible to recommend them as optimal.

Effect of nicosulfuron on dynamic changes in the starch-sugar interconversion in sweet maize (Zea mays L.)

Starch is an important reserve of sugar, and starch-sugar conversion in plants plays an important role in the response of plants to various abiotic stresses. Nicosulfuron is a post-emergence herbicide commonly applied to maize fields. However, it is unclear how sucrose and starch in sweet corn are converted to accommodate nicosulfuron stress. Field and pot experiments were conducted to study the effects of nicosulfuron on the sugar metabolism enzymes, starch metabolism enzymes, non-enzyme substances, and expression of key enzyme genes in leaves and roots of sweet maize seedlings. Accordingly, this research compared the responses of the sister lines HK301 and HK320, which are nicosulfuron tolerant and sensitive, respectively. Under nicosulfuron stress, compared with HK301 seedlings, the accumulation of stem and root dry matter of HK320 seedlings was significantly reduced, resulting in a lower root-to-shoot ratio. Compared with HK320 seedlings, nicosulfuron stress significantly increased the sucrose, soluble sugar, and starch contents in HK301 leaves and roots. This may be related to the enhanced carbohydrate metabolism under nicosulfuron stress, including significant changes in sugar metabolism enzyme activity and the levels of SPS and SuSys expression. Further, under nicosulfuron stress, sucrose transporter genes (SUC 1, SUC 2, SWEET 13a, and SWEET 13b) in the leaves and roots of HK301 seedlings were significantly upregulated. Our results emphasize that changes in sugar distribution, metabolism, and transport can improve the adaptability of sweet maize to nicosulfuron stress.

MCC-Net: A class attention-enhanced multi-scale model for internal structure segmentation of rice seedling stem

Internal structural parameters of rice seedling stems are of great significance for rice growth detection, rice selection, breeding, and damage examination. Aiming at the problems of non-repeatability and low detection accuracy in the existing plant internal structure phenotypic traits detection methods, this paper presents a non-destructive segmentation method for examining the internal structure of rice seedling stems based on deep learning. We use a standard X-ray CT imaging technology to obtain non-destructive tomographic images of rice seedling stems and then design a class attention-enhanced multi-scale segmentation model (MCC-Net), where UNet is used as the backbone network. Specifically, the proposed MCC-Net mainly consists of three core components: multi-scale convolutional block (MCB), coordinate spatial attention (CSA) module, and class attention enhancement (CAE) module. MCB is the main component of the encoder to improve the feature extraction ability of the model for regions of different sizes in the internal structure. CSA is embedded into the UNet skip connections to enhance the expression of effective features and automatically locate the regions with different structures of rice seedling stems. CAE is designed to calculate the dependencies between image pixels and categories, which can enhance the feature expression from the perspective of categories and correct the category errors in the segmentation results. The experimental results show that MIOU, average dice coefficient and average precision of our proposed MCC-Net model on the self-built rice seedling stem CT image dataset are 92.56%, 96.33% and 96.59% respectively. Compared with several state of the art models, the proposed model achieves better segmentation performance on the rice seedling stem CT image dataset.

Influence of Sowing Media and Variety on Growth Parameters and Disease Incidence of Early Cauliflower (Brassica oleracea var. botrytis) Seedlings

Healthy seedling production is prerequisite for raising vigorous and profitable crops. The present investigation was carried out at Assam Agricultural University, Jorhat, Assam in the year 2018 and 2019 to access the impact of sowing media and variety on growth and incidence of disease in nursery. The treatments consisted of four different sowing media [M1-cocopeat (60): vermiculite (20): perlite (20), M2-cocopeat (50): vermicompost (50), M3-cocopeat (50): vermicompost (50): microbial consortium and M4-Conventional nursery] and two varieties [V1 (White Diamond) and V2 (CFL1522)].Thus, 8 treatment combinations were laid out in a 4x2 factorial arrangement in a Randomized Completely Block Design (RCBD) with three replications. The treatment M1, M2 and M3 were inside green house. The results revealed that seedlings raised in different sowing media surpassed the conventional sowing media for growth attributes and disease incidence. The highest seedling stem diameter (0.50 cm), fresh weight (5.44 g) and highest dry weight (0.64 g) was recorded by seedlings grown in M2 i.e cocopeat(50):vermicompost (50), while M3-cocopeat (50): vermicompost (50): microbial consortium recorded maximum seedling growth index (1469.86). The lowest value for all the growth parameters were recorded in conventional nursery(M4). Non-significant effect of variety was noticed for seedling stem diameter. Variety V1 (White Diamond) registered maximum seedling fresh weight (4.12 g), dry weight (0.43 g) and seedling growth index (1254.49).The least disease incidence (2.36 %) was recorded in M3 i.e cocopeat (50): vermicompost (50): microbial consortium and in variety V2 (CFL1522) with 4.76 %. The interaction effect was also found to be significant for growth parameter as well as for disease incidence. The treatment combination M2V1 recorded the maximum seedling stem diameter (0.53 cm), fresh weight (5.50 g) and dry weight (0.66 g) while M3V2 was found to be superior than all other treatment combination with maximum seedling growth index (1482.03) and with the lowest disease incidence ( 2.11 %).Since M3 contains the component of M2 and resulted the lowest incidence of disease which is an important criteria of quality seedlings and considering the superiority of V1 with respect to most of the growth parameters it can be concluded that for producing good quality seedlings of early cauliflower under protected condition the treatment combination M3V1 can be used .

Design and Test of A Force Feedback Seedling Pick-Up Gripper for An Automatic Transplanter

Aiming at the problems of seedling injury and planting leakage due to the lack of seeding clamping force detection and real-time control in vegetable transplanting, a force feedback gripper was developed based on the linear Hall element. The mechanical properties of the stem of pepper cavity seedlings were first analyzed to provide a basis for the design of the gripper. A linear Hall sensor, a magnet, an elastic actuator, and an Arduino Uno development board make up the grasping force detecting system. Upon picking up a seedling, the elastic actuator, which is connected to the magnet, bends like a cantilever beam. As a result of the micro-displacement created by the elastic actuator, the Hall sensor’s voltage changes and can be used to determine the clamping force. Detection avoids direct contact between the sensor and the cavity seedlings, reducing the risk of sensor damage. Finite element method (FEM) simulations were used to determine the initial spacing between the magnet and Hall sensor and the effect of the elastic actuator. Control commands are sent to the servo based on the gripping force collected by the Arduino Uno board. Finally, the functions of accurate measurement, display, storage, and control of the clamping force of the cavity tray seedlings are realized, so that the damage rate of the cavity tray seedlings is reduced. In order to explore the influence of the elastic actuators on the clamping force detection system and the performance of the force feedback gripper, a calibration test of the clamping force detection system and a test of the indoor transplantation of pepper seedlings were carried out. Based on the calibration test, the clamping force detection system has a sensitivity of 0.0693 V/N, linearity of 3.21%, an average linear coefficient of determination of 0.986, and a range of 10 N, which fully meet the clamping force detection accuracy requirements during transplantation. Indoor tests showed that the force feedback gripper was stable and adaptable. This study can provide a reference for detecting and controlling clamping forces during transplantation.

Allelopathic Toxicity of Cyanamide Could Control Amaranth (Amaranthus retroflexus L.) in Alfalfa (Medicago sativa L.) Field.

The inclination toward natural products has led to the onset of the discovery of new bioactive metabolites that could be targeted for specific therapeutic or agronomic applications. Despite increasing knowledge coming to light of allelochemicals as leads for new herbicides, relatively little is known about the mode of action of allelochemical-based herbicides on herbicide-resistant weeds. Cyanamide is an allelochemical produced by hairy vetch (Vicia villosa Roth.). This study aimed to detect the toxicity of cyanamide to alfalfa and amaranth. Seed germination experiments were carried out by the filter paper culture, and the seedling growth inhibition experiment was carried out by spraying alfalfa (Medicago sativa L.) and amaranth (Amaranthus retroflexus L.) seedlings with cyanamide. The results showed that when the concentration of cyanamide was 0.1 g·L-1, the germination of amaranth seeds could be completely inhibited without affecting the germination of alfalfa seeds. At the concentration of 0.5 g·L-1, cyanamide could significantly inhibit the growth of the root and stem of amaranth seedlings but did not affect the growth of alfalfa. This effect was associated with the induction of oxidative stress. The ascorbate peroxidase (APX) and catalase (CAT) activity of amaranth decreased by 6.828 U/g FW and 290.784 U/g FW, respectively. The malondialdehyde (MDA) content, peroxidase (POD), and superoxide dismutase (SOD) activity of amaranth firstly increased and then decreased with the increasing concentration of CA. These enzyme activities of amaranth changed more than that of alfalfa. Activities of the antioxidant enzymes APX, CAT, POD, and SOD and the content of MDA varied dramatically, thereby demonstrating the great influence of reactive oxygen species upon identified allelochemical exposure. In addition, cyanamide can also inhibit the production of chlorophyll, thereby affecting the growth of plants. From the above experiments, we know that cyanamide can inhibit the growth of amaranth in alfalfa fields. Thus, the changes caused by cyanamide described herein can contribute to a better understanding of the actions of allelochemical and the potential use of cyanamide in the production of bioherbicides.