Plant Level Research Articles

Application of Biochar-Immobilized Bacillus megaterium for Enhancing Phosphorus Uptake and Growth in Rice

Phosphorus (P) is an essential nutrient for rice growth, and the presence of phosphate-solubilizing bacteria (PSB) is an effective means to increase soil P content. However, the direct application of PSB may have minimal significance due to their low survival in soil. Biochar serves as a carrier that enhances microbial survival, and its porous structure and surface characteristics ensure the adsorption of Bacillus megaterium. Inoculating rice husk biochar-immobilized with Bacillus megaterium (BMB) resulted in dissolved inorganic and organic P levels of 39.55 and 31.97 mL L−1, respectively. Subsequently, rice pot experiments were conducted to investigate the response of soil microbial P mobilization and P uptake in rice to fertilizer inputs. The organic fertilizer (OF) combined with BMB treatment (MOF) showed the highest soil available phosphorus (AP) at 38 days, with a value of 7.83 mg kg−1, as well as increased the pqqC abundance while decreasing the abundance of phoD bacterial communities compared with the control. Furthermore, the bioavailable P reservoir (H2O–Pi and NaHCO3–Pi) in soil was greatly increased through the fertilizer input and microbial turnover, with the highest H2O–Pi (3.66 mg kg−1) in OF treatment and the highest NaHCO3–Pi (52.65 mg kg−1) in MOF treatment. Additionally, carbon utilization analysis was applied using the commercial Biolog system, revealing that the MOF treatment significantly increased the utilization of carbohydrates, polymers, and amino acid carbon sources. Moreover, compared to the control, MOF treatment significantly increased the shoot (0.469%) and root P (0.516%) content while promoting root development and thereby supporting rice growth. Our study demonstrates that the MOF treatment displayed higher P levels in both soil and rice plants, providing a theoretical basis for further understanding the role of biochar-based bacterial agents in rice P management.

Barley leaf cell-wall responses to the penetration by adapted and nonadapted powdery mildew fungi revealed with the thermal-source based Fourier transform infrared microspectroscopy and focal plane array

Infrared microspectroscopy allows for detailed characterization of functional groups at subcellular levels in plants. In this study, barley leaves were inoculated with Blumeria graminis f. sp. hordei (Bgh, adapted) and B. graminis f. sp. tritici (Bgt, nonadapted). Globar-based transmission Fourier transform infrared (gFTIR) microspectroscopy equipped with an upgraded high-resolution focal plane array (FPA) detector which enabled the rapid acquisition of high magnification imaging with a 3.3-μm × 3.3-μm capacity, was employed to quantitatively analyse the cell wall (CW) modification over individual leaf cells in response to attempted penetration at 24 hours post-inoculation. Univariate and multivariate analyses of gFTIR spectra revealed distinct changes in several CW functional groups upon attempted penetration by Bgt, with significant increases in the integrated areas of cellulose, hemicellulose, methyl-esterified pectins and lipid regions compared to cells without penetration. Notably, neither guaiacyl (G) nor syringyl (S) lignin increased significantly in CWs near Bgt penetration sites relative to nonpenetrating controls, though the G/S ratio was higher than in Bgh-penetrated sites. These findings suggest early and rapid CW modifications occur during the nonhost resistance to Bgt. This study also confirms previous results obtained using synchrotron-based FTIR (sFTIR), demonstrating that both gFTIR and sFTIR are valuable for studying plant CW apposition, with gFTIR being more accessible and rapid for imaging over large areas with compatible quality and resolution to sFTIR.

Cell-Type Specific miRNA Regulatory Network Responses to ABA Stress Revealed by Time Series Transcriptional Atlases in Arabidopsis.

In plants, microRNAs (miRNAs) participate in complex gene regulatory networks together with the transcription factors (TFs) in response to biotic and abiotic stresses. To date, analyses of miRNAs-induced transcriptome remodeling are at the whole plant or tissue levels. Here, Arabidopsis's ABA-induced single-cell RNA-seq (scRNA-seq) is performed at different stages of time points-early, middle, and late. Single-cell level primary miRNAs (pri-miRNAs) atlas supported the rapid, dynamic, and cell-type specific miRNA responses under ABA treatment. MiRNAs respond rapidly and prior to target gene expression dynamics, and these rapid response miRNAs are highly cell-type specific, especially in mesophyll and vascular cells. MiRNA-TF-mRNA regulation modules are identified by identifying miRNA-contained feed-forward loops (M-FFLs) in the regulatory network, and regulatory networks with M-FFLs have higher co-expression and clustering coefficient (CC) values than those without M-FFLs, suggesting the hub role of miRNAs in regulatory networks. The cell-type-specific M-FFLs are regulated by these hub miRNAs rather than TFs through sc-RNA-seq network analysis. MiR858a-FBH3-MYB module inhibited the expression of MYB63 and MYB20, which related to the formation of plant secondary wall and the production of lignin, through M-FFL specifically in vascular. These results can provide prominent insights into miRNAs' dynamic and cell-type-specific roles in plant development and stress responses.

Antibiotic Pollution Level and Ecological Risk Assessment of Township Wastewater Treatment Plants

Due to the abuse of antibiotics, a large amount of antibiotics has been entering wastewater treatment plants （WWTPs）, but the pollution of antibiotics in township WWTPs has not attracted much attention. To understand the contamination level and removal characteristics, and the risks to aquatic organisms and human health, samples collected from the inlet and outlet of 15 township WWTPs were investigated. The results showed that tetracyclines （TCs） had the highest concentration in the inlet and outlet waters, in which the concentrations of TC and oxytetracycline （OTC） reached （4 943.69±4.31） ng·L-1 and （3 907.81±52.04） ng·L-1. As for antibiotic removal, the A/O and A2/O processes had a better antibiotic removal capacity than those of the MBR process. Ecological risk assessment showed that TCs and fluoroquinolones （FQs） had a higher risk to aquatic organisms. However, sulfonamides （SAs） would pose a low risk to aquatic organisms. Although antibiotics pose a risk to aquatic organisms, the risk to human health is negligible. The results of this study could provide support for the upgrading of township WWTPs and the formulation of regional antibiotic discharge standards in the future.

Alleviation of cadmium stress and improved growth performance of periwinkle (Catharanthus roseus L.) by foliar application of zinc oxide nanoparticles

Cadmium (Cd) is a nonessential and very toxic element that confines the growth of ornamental plants worldwide. Nanoparticles (NPs) have been used as a novel approach to act as nano-fertilizers and directly alleviate the Cd stress. However, its defensive mechanisms are not well understood in ornamental/medicinal plants, especially Catharanthus roseus (periwinkle). The objectives of the current experiment are intended to examine the impacts of zinc oxide nanoparticles (ZnONPs; 25 mg l-1) on the reduction of oxidative stress by enhancing antioxidant activities, physiological improvements, and elemental status in periwinkle plant parts under Cd stress (0.5 mM). The periwinkle plants were transplanted and exposed to Cd stress one week later by soil drenching, whereas, ZnONPs were applied after 14 days by foliar supplementation. The Cd toxicity significantly reduced the morphological traits, negatively affected the pigments and photosynthetic apparatus, abridged antioxidant enzyme activities, and Cd accrual in periwinkle plants. However, exogenous ZnONPs supplementation produced elevated plant height, flower numbers, root length, plant fresh and dry biomass, chlorophyll, and carotenoid contents in Cd-stressed plants. Likewise, the ZnONPs have also regulated the gaseous exchange rates, antioxidant enzymes (SOD, CAT, APX), soluble protein, and free proline contents in Cd-polluted periwinkles. The application of ZnONPs also considerably reduced the hydrogen peroxide (−25 %) and malondialdehyde (−47 %), activated by Cd stress. Furthermore, the Zn and Cd contents were also elevated and reduced, respectively, in ZnONPs supplied Cd-stressed plants. The present experiment recommends that the exogenous supplementations of ZnONPs are a feasible and sustainable strategy for enhancing the growth attributes and reducing the Cd levels in periwinkle plants in metal-hoarded soil conditions.

An Approach to Develop a Model to Detect the Phosphorus and Potassium Deficiency in Paddy Crop on Agriculture Farm Using DIP ML

Excessive use of fertilizers harms the environment and disrupts plant habitats, while also raising costs for farmers. Proper timing and amounts of nutrients are crucial for plant health and environmental balance. The greenness of rice leaves indicates their chlorophyll and nutrient levels. Agronomy studies show rice plants need 10 nutrients, including primary ones like Nitrogen (N), Phosphorus (P), and Potassium (K), and secondary ones like Iron (Fe), Manganese (Mn), Copper (Cu), Zinc (Zn), Boron (B), Molybdenum (Mo), and Chlorine (Cl). Leaf nitrogen concentration (LNC) is highly correlated with chlorophyll content. There are several tools on LEAF+ to measure it, such as leaf color (LCC), SPAD, chlorophyll or nitrogen. Since these tools are cost-effective and not available to all farmers, LCC offers farmers the ability to estimate plant nitrogen needs in real-time for efficient fertilizer use and increased rice yield. Notable innovation in agriculture is the Leaf Color Chart (LCC), developed by Japanese experts. It measures chlorophyll levels in rice plants and aids in nitrogen management without harming the plant. Today, LCC is used globally to improve production efficiency and optimize nitrogen application rates. The remaining 2 major nutrients potassium and phosphorus can also be measured by experimentally expanding the available database of LCC, as has been done in the two models developed in this research paper.

SANITATION AND ENVIRONMENTAL PROBLEMS IN HASSIMESSAOUD CITY (LOWER SAHARA - ALGERIA)

The dysfunction of the liquid waste sanitation systems is noticeable in the city of Hassi-Messaoud: wastewater stagnates in empty spaces (sludge). The consequences of this dysfunction on the living environment and the natural ecosystem are becoming more and more serious and call for appropriate decisions from all the actors involved. In addition, the development of oil activities will lead to significant changes in the environment, particularly in water resources. Industrial pollution has very negative effects on the quality of water resources. It has to be treated at the plant level, especially to remove toxic elements. This situation suggests that if nothing is done to correct the situation, pollution could become a serious cause of water shortages in the future.

A novel tank-mix formulation increases the efficacy of alphabaculoviruses on different phylloplanes.

Spodoptera littoralis Boisduval (Lepidoptera: Noctuidae) and Spodoptera exigua Hübner (Lepidoptera: Noctuidae) pose substantial threats to many crops, necessitating the exploration of biopesticides as potential chemical alternatives. One alternative is baculoviruses; however, their instability in the field has hindered their widespread use. Host plant phylloplane affects baculovirus activity at varying levels in different host plants. Formulation contributes significantly to optimizing the baculoviral stability on different phylloplanes against environmental conditions; however, it is expensive and difficult to make in developing or nondeveloped countries. In the current study, we developed a simple tank-mix application (MBF-Tm5) for immediate use, resembling the characteristics of a suspension concentrate formulation for Spodoptera littoralis nucleopolyhedrovirus (SpliNPV) and Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV). We examined their biological activity against 2nd instar larvae first on an artificial diet under laboratory conditions and on eggplant and pepper phylloplane in greenhouse conditions compared to plain viruses. This formulation exhibited no significant improvement in the biological activity of both viruses on an artificial diet under laboratory conditions but significantly improved the biological activity of both viruses on both plants under greenhouse conditions. The original activity remaining (OAR%) of both unformulated and formulated viruses decreased over time under greenhouse conditions; however, the OAR value of both viruses on eggplants was significantly higher than on pepper plants. Overall, the tank-mix simple formulation of baculoviruses might be a great alternative for improved stability in nature, providing better control.

Low-pass nanopore sequencing for measurement of global methylation levels in plants

Low-pass nanopore sequencing for measurement of global methylation levels in plants

Calcium signaling in hypoxic response.

Plants can experience a lack of oxygen due to environmental conditions such as flooding events or intense microbial blooms in the soil, and from their own metabolic activities. The associated limit on aerobic respiration can be fatal. Therefore, plants have evolved sensing systems that monitor oxygen levels and trigger a suite of metabolic, physiological and developmental responses to endure, or potentially escape, these oxygen limiting conditions. Low oxygen stress has long been known to trigger changes in cytosolic Ca2+ levels in plants and recent work has seen some major steps forward in characterizing these events as part of a Ca2+-based signaling system through: (1) defining how hypoxia may trigger and then shape the dynamics of these Ca2+ signals and, (2) identifying a host of the downstream elements that allow Ca2+ to regulate a wide-ranging network of hypoxia responses. Calcium transporters such as the CAX family of Ca2+/H+ antiporters at the tonoplast have emerged as important components of the system that forms hypoxia-related Ca2+ signals. Downstream lies a web of Ca2+-responsive proteins such as the calmodulin like proteins (CMLs), Ca2+-dependent kinases (CPKs), the calcineurin-B like proteins (CBLs) along with their interacting kinases (CIPKs). A host of other regulators such as reactive oxygen species and lipid-mediated signals then act in parallel to the Ca2+-dependent events to closely control and coordinate the myriad responses that characterize the plant's low oxygen response.

Effects of Intercropped Insectary Plants (Sweet Alyssum, Coriander, and White Mustard) on Elemental Composition and Antioxidant Levels in Broad Bean Plants.

Insectary plants, such as sweet alyssum, coriander, and white mustard, are well known for their traits that attract beneficial insects, allowing them to protect crops from pests. The aim of the study was to analyze the compounds that are important in the antioxidant response, such as malondialdehyde, ascorbic acid, proline, total phenolics, and total flavonoids, as well as the content of elements, including macroelements (K, Mg, Na, Ca, P, and S) and heavy metals (Cd, Cu, Zn, Pb, Ni, Mn, and Fe) in broad bean plants. These plants were grown in field conditions as the main protected plant alongside a mixture of three insectary plants at different proportions of the individual components. The soil was analyzed in terms of the above-mentioned elements, as well as in terms of its enzymatic activity (arylsulfatase, β-glucosidase, dehydrogenase, FDA (fluorescein diacetate), and acid phosphatase). The introduction of insectary plant mixtures did not cause major changes in the content of the elements in the soil. The changes in the content of elements in broad bean leaves depended on the type of element and the proportion of individual components in the companion plant mixture. However, a general trend of increasing macronutrient content was observed, influenced by the presence of companion plants. All types of companion plant mixtures used enhanced the activity of FDA, while the mixture with 50% sweet alyssum additionally caused an increase in arylsulfatase activity (more than 2 fold). The companion plants improved the physiological condition of the protected plant, which was reflected in the reduced content of proline and total flavonoids. Considering the response of the protected plant to the proposed intercropped plant mixtures and their effect on broad bean growth, it appears that the most suitable mixtures are those with an equal share of all three plant species or a mixture with a predominance of sweet alyssum.

Cadmium sulfide (CdS) nanoparticles and Cd2+ accumulated by Portulaca oleracea L. using a hydroponic system: Constructed wetland perspective.

To identify cadmium sulfide nanoparticles (CdS NPs) and Cd hyperaccumulators for Cd-contaminated waters. A potential species of constructed wetland plants (P. oleracea) was examined for their CdS NPs and Cd ions tolerance and accumulation. This study evaluated the P. oleracea life traits response, Cd accumulation, bioaccumulation factor (BCF), and translocation factor (TF) to assess their abilities to absorb and accumulate Cd. P. oleracea demonstrates high tolerance to both CdS NPs and Cd stress, with no significant effects observed on biomass, leaf color, plant height, or root length. High accumulation of Cd was noted in plant tissues, with higher Cd in the roots than in the stems and leaves. The Cd levels in plants subjected to CdS NPs were higher than those in the Cd treatment group. CdS NPs aggregates were identified within the plant cells in root and shoot tissues using transmission electron microscopy (TEM). The BCF values ranged from 6.96 to 548.10 for the Cd treatment and 12.91-499.66 for CdS NPs, indicating the ability of P. oleracea to accumulate Cd and NPs. Additionally, TF values for Cd at 0.05 and 0.1 mg/L were above 1, showing effective translocation capability. The findings suggest that P. oleracea demonstrates significant potential as a Cd-hyperaccumulator, exhibiting a robust ability to extract Cd and CdS NPs from contaminated waters. It is a feasible plant in a constructed wetland for Cd removal.

Long‐term response of Posidonia oceanica meadow restoration at the population and plant level: implications for management decisions

In recent years, numerous efforts to transplant Posidonia oceanica have been carried out in the Mediterranean Basin for experimental and large‐scale restoration purposes. However, data on the long‐term outcomes of these initiatives remain scarce. This study aims to address this gap by investigating the long‐term response of transplanted P. oceanica at both the population and plant level in comparison to adjacent natural meadows. We report on two large‐scale transplantation sites in Italy: Santa Marinella in the Central Tyrrhenian Sea and Ischia Porto in the Southern Tyrrhenian Sea, assessing their progress 14 and 10 years after transplantation, respectively. Descriptors of the meadows and of individual plants were investigated through field and laboratory activities. Sampling was conducted in both transplanted and adjacent control areas within the natural P. oceanica meadow. After about a decade, shoot density in the transplanted areas equaled that of the natural ones. Nevertheless, phenological and lepidochronological descriptors in the transplanted areas still did not match those of the natural meadows. Our work provides crucial information into the restoration process of P. oceanica, with implications for managing this habitat in line with recent EU marine legislation.

Impact of Beneficial Microorganisms Inoculated Cotton Plants on Spodoptera exigua (Lepidoptera: Noctuidae).

This study discusses plant-mediated effects of beneficial soil-borne microorganisms on population growth parameters of Spodoptera exigua (Lepidoptera: Noctuidae), a major cotton pest. In particular, we investigated the impact of these microorganisms on oxidative stress, chlorophyll content, and sugar and protein levels in cotton plants, and how these changes in the plant affect the survival, development, reproduction, and ultimately population growth of the pest. A longer preadult period, lower preadult survival rate, and lower reproduction were obtained for the pest cohort feeding on treated plants, which resulted in lower population parameters, i.e., intrinsic growth rate, finite growth rate, and net reproduction rate. The population projection results showed the same trend as the population parameters. These results can be attributed to the changes caused by microorganisms in the treated plants. There was no oxidative stress in the treated plants. Instead, the chlorophyll content in these plants increased, and the protein-carbohydrate ratio decreased. Additionally, we assessed the effects of plant-insect-microorganisms interaction on total glutathione levels, glutathione S-transferase, and esterase enzyme activities in S. exigua. Overall results indicate that beneficial microorganisms tested enhance the plant's ability to defend against the pest. Additionally, the findings from this study provide valuable insights into the complex interplay among plants, microorganisms, and pests, offering potential strategies for incorporating these interactions into pest management practices.

Impact of increasing workforce racial diversity on black-white disparities in cardiovascular disease mortality

BackgroundStructural racism’s influence on workforce policies and practices presents possible upstream targets for assessing and reducing racial health disparities. This study is the first to examine workforce racial diversity in...

Effect of Nickel Chloride and Cobalt Chloride on Physiological Characteristics of Myriophyllum Verticillatum and Schoenoplectus Litoralis

The object of the research was to determine the adverse effects of different concentrations of nickel chloride and cobalt chloride (10, 20, and 30) mg/L for a month on the physiological characteristics of Myriophyllum verticillatum and Schoenoplectus litoralis as well as assess the concentration of total chlorophyll and protein content. The results of the study showed that the concentrations of the components increased at the end of the investigation in the water plants used for the examination as compared with the control sample, in addition to a decrease in the protein and chlorophyll levels of the water plants exposed to the effects of heavy metal.

The Effect of Cadmium Salts on the In Vitro Growth and Development of Sorghum (Sorghum)

Purpose. To determine the effect of different concentrations of cadmium salt on the growth and development of shoots of different sorghum species in vitro and to select tolerant forms for developing breeding genotypes resistant to abiotic factors. Methods. The study involved different sorghum species: grain, broomcorn, Sudan grass, and soryz. Sorghum bicolor cultivar 'Stepovyi 8' was used as a control. Nutrient media were prepared using the standard Murashige and Skoog (MS) formulation. Sorghum seeds were sterilized with a solution of Bilyzna (bleach). Clonal micropropagation was conducted through direct selection with the addition of cadmium chloride (CdCl₂) and cadmium sulfate (CdSO₄) at concentrations ranging from 1.0 to 45.0 mg/L. The resulting shoots were evaluated on days 3 and 7 for the percentage of viable, necrotic, and dead shoots, as well as their biometric parameters. Results. The tolerance levels of sorghum plants varied depending on the species, the type of cadmium salt, and the salt concentration. Sudan grass exhibited the highest tolerance, whereas broomcorn was the most sensitive. This trend was consistent for both cadmium chloride and cadmium sulfate. At a concentration of 10.0 mg/L CdCl₂, shoot viability remained high in all treatments (82–95%). Increasing the concentration to 15.0 mg/L reduced viability to 70–87%, while at a concentration of 20.0 mg/L, it dropped to 44–54%. Concentrations of 30.0 mg/L and higher were critical, reducing shoot viability to 2–12%. The maximum toxic concentration (45.0 mg/L) caused the death of broomcorn shoots. In comparison, CdSO₄ demonstrated lower toxicity under similar conditions. At a concentration of 10.0 mg/L, shoot viability was 90–98%, while at a concentration of 15.0 mg/L, it was 80–95%. Even at higher concentrations (20.0–25.0 mg/L), viability remained higher compared to CdCl₂, and the maximum concentrations provided survival of a small proportion of viable shoots (up to 6%). Necrotic shoots began to appear at CdCl₂ concentrations as low as 7.5 mg/L, with the highest percentage of necrosis recorded in broomcorn plants. CdSO₄ caused less necrosis, even at higher concentrations (10.0–17.5 mg/L), indicating its reduced toxicity. At low cadmium salt concentrations (1.0–5.0 mg/L), the number of newly formed shoots was high in all treatments. CdSO₄ promoted greater shoot formation compared to CdCl₂. At 1.0 mg/L, the number of new shoots ranged from 7 to 18, while at 15.0 mg/L, this number decreased to 2–10. Conclusions. CdSO₄ is a less toxic alternative to obtain viable sorghum shoots in cadmium-containing media. The best results were observed at concentrations up to 10.0 mg/L, particularly for Sudan grass and soryz. Breeding programs should consider the species-specific tolerance of sorghum to heavy metals, with special attention to Sudan grass as the most tolerant species.

Source-sink manipulations through shading, crop load and water deficit affect plant morphogenesis and carbon sink priorities leading to contrasted plant carbon status in grapevine.

Shading, water deficit, and crop load shape plant development in a very plastic way. They directly influence the plant's carbon supply and demand to and from the different organs via metabolic, hydraulic and hormonal mechanisms. However, how the multiple environmental factors combine through these mechanisms and how they interplay with carbon status, vegetative and reproductive development and carbon assimilation of the plant needs to be investigated in the context of current climatic and technological constraints. With this aim, two experiments were conducted on potted grapevines, subjected to ten combinations of treatments. Axis organogenesis, berry characteristics at harvest (weight, number and total soluble content) and a series of leaf traits (gas exchanges, non-structural carbohydrate contents, water potential and SPAD values) were measured. Grapevine development showed different responses corresponding to different sink priorities: under shade, vegetative development was maintained at the expense of berries, whereas under high crop load and water deficit, berry growth was the priority sink. These responses were accompanied by changes in the specific leaf area in agreement with the shade avoidance syndrome. These different strategies affected the plant carbon status as estimated through the starch content in leaves. Leaf starch content was not affected by shade, while it decreased under water deficit and crop load conditions. Carbon assimilation was decreased under water deficit, low crop load and shading conditions. Hydraulic properties and leaf nitrogen content correlated withthis decrease while plant carbon status has a very low impact. Finally, no major interaction between the different types of constraints were observed both on morphological and functional variables. Depending on the type of abiotic constraints, grapevine exhibits specific morphogenetic responses at plant and leaf levels. The absence of interaction between the different constraints showed that grapevine is able to exhibit independent responses to shade and water deficit. This result is of major importance to further design new agricultural systems facing multiple abiotic constraints, such as those in agroforestery and agrivolatic system.

Phytochrome alleviates cadmium toxicity by regulating gibberellic acid and brassinolide in Nicotiana tabacum L.

Soil cadmium (Cd) pollution has emerged as a substantial environmental challenge globally, hampering crop production and endangering human health. Here, we found that photoreceptor phytochromes (PHYs) were involved in regulating Cd tolerance in tobacco. Compared to wildtype (WT) plants, phytochrome-defective mutants (phyA, phyB, phyAB) displayed Cd sensitive phenotype, and had a higher reactive oxygen species (ROS) accumulation and malondialdehyde content. However, differences in Cd concentration among phyA mutants, phyB mutants, phyAB mutants, and WT plants were not observed. Consequently, the higher tolerance promoted the biomass of WT plants, thereby increasing the Cd accumulation. Furthermore, Cd stress altered the levels of gibberellin (GA) and brassinosteroid (BR), and these phytohormones were higher in WT plants. GA3 application induced the transcription of genes encoding antioxidant enzyme and suppressed the expression of genes associated with chlorophyll degradation, inhibiting chlorophyll breakdown and decreasing ROS levels in plants under Cd stress conditions. Additionally, epibrassinolide spraying promoted the expression of genes related to chlorophyll synthesis, thereby increasing chlorophyll content and maintaining plant acquisition ability. Our results suggested that phytochromes enhanced the tolerance of Nicotiana tabacum to Cd stress through regulating BR and GA.

An automatic 3D tomato plant stemwork phenotyping pipeline at internode level based on tree quantitative structural modelling algorithm

Phenotypic traits of stemwork are important indicators of plant growing status, contributing to multiple research domains including yield estimation, breeding engineering, and disease control. Traditional plant phenotyping with human work faces serious bottlenecks on labour intensity and time consumption. In recent years, the application of Quantitative Structural Modeling (QSM) together with three-dimensional (3D) sensor-based data acquisition techniques provides a feasible solution towards the automatic stemwork phenotyping. Nevertheless, existing QSM-based pipelines are sensitive towards the point cloud quality, and mostly focus on the phenotyping at plant or organ level. Information at internode level which are closely related to photosynthesis and light absorption was generally overlooked. To this end, a 3D automatic stemwork phenotyping pipeline is developed for tomato plants at both plant and internode level. Coloured point clouds are taken as the sensor input of the pipeline. A semantic segmentation based on PointNet++ was used to detect and localise the stemwork points. To improve the quality of the segmented stemwork point clouds, a density-based refining pipeline is proposed containing three main processes: non-replacement resampling, interference branch removal, and noise removal. A Tree Quantitative Structural Modeling (TreeQSM) algorithm was then applied to the stemwork point cloud to construct a digital reconstruction. The target phenotypic traits were finally calculated from the digital model by employing an internode association process. The proposed phenotyping pipeline was evaluated with a test dataset containing three tomato plant cultivars: Merlice, Brioso, and Gardener Delight. The related rooted mean squared errors of calculated internode length, internode diameters, leaf branching angle, leaf phyllotactic angle, and stem length range from 4.8 to 64.4%. Considering the time consuming manual phenotyping process, the proposed work provides a feasible solution towards the high throughput plant phenotyping, from which facilitates the related research on plant breeding and crop management.