Stem Diameter Research Articles

A novel method for tomato stem diameter measurement based on improved YOLOv8-seg and RGB-D data

The automatic acquisition of crop information can promote the rapid development of precision agriculture. Tomatoes, as a representative greenhouse crop, can demonstrate their growth status and overall health could be exhibited by measuring the diameters of their main stems. Automated measurement of the diameters of the trunk stems can not only reduce labor costs, but also enhance efficiency, thereby facilitating the improvement of tomato cultivation and planting management. Therefore, this study proposes a novel method based on an instance segmentation algorithm combined with RGB-D data to measure the diameter of a tomato trunk. First, we utilize the improved YOLOv8-seg to acquire the masks and bounding boxes of the buds and stems. Namely, we replace the SPPF module with Soft-SPPF to enhance the model’s capability to extract multi-scale features. Additionally, we improve the neck layer using cross-stage and weighted feature fusion to enhance the feature fusion effect. Then, we design a method to calculate the diameter of the tomato trunk by utilizing the instance segmentation results and depth information. Specifically, we first obtain the measurement point and the ROI (Region of Interest) to be measured by identifying the intersection between the bounding box of the bud and the straight line fitted by the stem mask in an image. We then filter out irrelevant depth information using the mask within the ROI, optimize the coordinate values of the measurement point, and calculate the main stem diameter. The results demonstrate that the measurements obtained in this study have a RMSE (Root Mean Square Error) of 1.5 mm and a MAPE (Mean Absolute Percentage Error) of 12.37 % compared with the manual measurements. Compared with the method based on object detection, the direct acquisition of contour information for the target instances by the instance segmentation algorithm reduces the algorithmic complexity of the subsequent processing. The proposed method can offer precise and reliable information on the diameter of the main stem of a tomato in real-world scenarios. It can be extended to other types of crops in greenhouses.

Effectiveness Test of Indigenous Plant Growth Promoting Rhizobacteria (PGPR) Isolate on the Growth of Acehnese Patchouli (Pogostemon cablin Benth.) Sidikalang Variety

Plant Growth Promoting Rhizobacteria (PGPR) is a group of bacteria that live saprophytically in the root area (rhizosphere) acting as a plant growth promoter. The purpose of this study was to test the effectiveness of indigenous rhizobacterial isolates from Aceh Besar and Aceh Tengah in supporting the growth of Aceh patchouli Sidikalang variety. This research was conducted at the Laboratory of Seed Science and Technology, Faculty of Agriculture, Syiah Kuala University and patchouli planting was carried out at the Patchouli Innovation Park (Nino Park), Syiah Kuala University, which took place from December 2022 to June 2023. This study used a non-factorial Randomized Group Design (RAK) with 3 replications. The factor studied was the type of rhizobacterial isolate consisting of 15 treatment levels, namely 1 treatment without rhizobacteria, 7 treatments given indigenous rhizobacterial isolates from Lambada, Seulimeum District, Aceh Besar Regency and 7 treatments given rhizobacterial isolates from Paya Tampu village, Rusip Antara District, Central Aceh Regency. The observation parameters studied are of plant height, number of leaves, number of branches, stem diameter, area per leaf blade, root length, root volume and wet biomass weight of plants. The results showed that indigenous rhizobacterial isolates from Aceh Besar and Aceh Tengah effectively increased the average plant height of Sidikalang variety patchouli at 4 and 8 MSA (26%, and 24%), number of leaves (46%, and 58%), number of branches (78% and 50%), area per leaf blade (34%), root length (19%), root volume (60%) and plant wet biomass weight (50.61%).

Mycorrhizal inoculation and fertilizer microdosing interactions in pearl millet (Pennisetum glaucum) under greenhouse conditions.

Soil fertility is a major constraint to agricultural development in the Sahel region of Africa. One alternative to reducing the use of mineral fertilizers is to partially replace them with microbes that promote nutrition and growth, such as arbuscular mycorrhizal fungi (AMF). Mineral fertilizer microdosing is a technique developed to enhance fertilizer efficiency and encourage smallholder farmers to adopt higher mineral fertilizer applications. A pot experiment was set up to study the effects of AMF inoculation on the mineral nutrition of pearl millet under mineral fertilizer microdosing conditions. The experimental setup followed a randomized complete block design with five replicates. The treatments tested on millet were an absolute control and eight microdoses derived from the combination of three doses of 15- 10-10 [nitrogen, phosphorus, and potassium (NPK)] mineral fertilizer (2 g, 3 g, and 5 g per pot), three doses of urea (1 g, 2 g, and 3 g per pot), and three doses of organic manure (OM) (200 g, 400 g, and 600 g), combined with and without AMF (Rhizophagus irregularis and Rhizophagus aggregatum). The parameters studied were growth, root colonization by AMF, and mineral nutrition. Plant height, stem diameter, root dry biomass, and percentage of root mycorrhization were measured. The results revealed a significant effect of the fertilizers on the growth of pearl millet compared to the control. AMF and OM treatments resulted in the highest biomass production. AMF combined with microdoses of NPK improved N and calcium (Ca) concentrations, while their combination with organic matter mainly improved the K concentration. Combining AMF with microdosed NPK and compost enhanced zinc (Zn) and nickel (Ni) concentrations. Root colonization varied from 0.55 to 56.4%. This investigation highlights the positive effects of AMF inoculation on nutrient uptake efficiency when combined with microdosing fertilization.

Populus trichocarpa EXPA6 Facilitates Radial and Longitudinal Transport of Na+ under Salt Stress.

Expansins are cell wall (CW) proteins that mediate the CW loosening and regulate salt tolerance in a positive or negative way. However, the role of Populus trichocarpa expansin A6 (PtEXPA6) in salt tolerance and the relevance to cell wall loosening is still unclear in poplars. PtEXPA6 gene was transferred into the hybrid species, Populus alba × P. tremula var. glandulosa (84K) and Populus tremula × P. alba INRA '717-1B4' (717-1B4). Under salt stress, the stem growth, gas exchange, chlorophyll fluorescence, activity and transcription of antioxidant enzymes, Na+ content, and Na+ flux of root xylem and petiole vascular bundle were investigated in wild-type and transgenic poplars. The correlation analysis and principal component analysis (PCA) were used to analyze the correlations among the characteristics and principal components. Our results show that the transcription of PtEXPA6 was downregulated upon a prolonged duration of salt stress (48 h) after a transient increase induced by NaCl (100 mM). The PtEXPA6-transgenic poplars of 84K and 717-1B4 showed a greater reduction (42-65%) in stem height and diameter growth after 15 days of NaCl treatment compared with wild-type (WT) poplars (11-41%). The Na+ accumulation in roots, stems, and leaves was 14-83% higher in the transgenic lines than in the WT. The Na+ buildup in the transgenic poplars affects photosynthesis; the activity of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT); and the transcription of PODa2, SOD [Cu-Zn], and CAT1. Transient flux kinetics showed that the Na+ efflux of root xylem and leaf petiole vascular bundle were 1.9-3.5-fold greater in the PtEXPA6-transgenic poplars than in the WT poplars. PtEXPA6 overexpression increased root contractility and extensibility by 33% and 32%, indicating that PtEXPA6 increased the CW loosening in the transgenic poplars of 84K and 717-1B4. Noteworthily, the PtEXPA6-promoted CW loosening was shown to facilitate Na+ efflux of root xylem and petiole vascular bundle in the transgenic poplars. We conclude that the overexpression of PtEXPA6 leads to CW loosening that facilitates the radial translocation of Na+ into the root xylem and the subsequent Na+ translocation from roots to leaves, resulting in an excessive Na+ accumulation and consequently, reducing salt tolerance in transgenic poplars. Therefore, the downregulation of PtEXPA6 in NaCl-treated Populus trichocarpa favors the maintenance of ionic and reactive oxygen species (ROS) homeostasis under long-term salt stress.

Understanding the Impact of Zinc and Boron Applications on Growth and Yield Attributes in Potato

Research examines the impact of zinc (Zn) and boron (B) on the growth, and yield of potato plants. The screen house experiment used four treatments: T1 (Control), T2 (Zn 5g/L), T3 (B 2g/L), and T4 (Zn 5g/L + B 2g/L). Growth characteristics were evaluated, such as the emergence percentage, plant vigor, number of stem /meter2, plant height, and stem diameter. In addition, essential yield metrics such as number of tubers, tuber weight (g), dry matter content, and specific gravity were also assessed. The findings indicated that concurrent administration of T4 had a substantial positive impact on the plant's vitality, height, stem thickness, and stem density per square meter compared to the control group. This suggests a cooperative influence of these micronutrients on the growth of plant structures. However, in terms of yield qualities, the use of Zn alone T2 led to the greatest tuber weight, dry matter content, and specific gravity. Showing that Zn plays a crucial role in maximizing tuber growth and quality. The treatment T4 enhanced yield parameters compared to the control, but it did not exceed the effects of either Zn or B individually in T2 and T3. This emphasizes the intricate interaction between these nutrients. However, when it comes to maximizing yield attributes in potato cultivation, using Zn alone may be more successful. The results indicate that customizing the management of micronutrients could optimize the growth and output of potatoes, hence enhancing agricultural productivity. Additional research is advised to investigate the most effective dosages and combinations

Enhancing Corn (Zea mays L.) Productivity under Varying Water Regimes with At-Plant Application of Xyway Fungicide.

A fungicide's ingredients can play a physiological role in crop water-management decisions. Our greenhouse study in 2021 demonstrated that Xyway LFR@FMC at-plant fungicide can significantly improve water-saving potential in corn. In 2022 and 2023, a field study was conducted to validate this finding. The 1.11 L ha-1 of Xyway LFR@FMC and no-fungicide/check were the main plot effects. Three water regimes, high (HI) and low (LO) numbers of irrigation events and rainfed (RF), were the subplot effect. Plants treated with Xyway LFR@FMC had significantly higher plant height, stem diameter, and leaf water potential (LWP), and had 11.9, 13.4, and 18.3% higher yield under RF, LO, and HI, respectively, in 2022. In 2023, there were no significant differences for the yield components and growth parameters when the combined effect of fungicide treatments and water regimes was considered. However, plants treated with the fungicide had a higher number of rows per ear, kernel number per row, and cob diameter compared to the check. There was no significant separation for yield among the water regimes in 2023, but the crop yield was overall higher for the fungicide-treated plots. Our results indicate that Xyway LFR@FMC fungicide has the potential to improve plant growth and protect the yield when limited water is applied.

Physiological traits, crop growth, and grain quality of quinoa in response to deficit irrigation and planting methods

Climate change has become a concern, emphasizing the need for the development of crops tolerant to drought. Therefore, this study is designed to explore the physiological characteristics of quinoa that enable it to thrive under drought and other extreme stress conditions by investigating the combined effects of irrigation water levels (100%, 75%, and 50% of quinoa's water requirements, WR as I1, I2 and I3) and different planting methods (basin, on-ridge, and in-furrow as P1, P2 and P3) on quinoa's physiological traits and gas exchange. Results showed that quinoa’s yield is lowest with on-ridge planting and highest in the in-furrow planting method. Notably, the seed protein concentrations in I2 and I3 did not significantly differ but they were 25% higher than those obtained in I1, which highlighted the possibility of using a more effective irrigation method without compromising the seed quality. On the other hand, protein yield (PY) was lowest in P2 (mean of I1 and I2 as 257 kg ha−1) and highest in P3 (mean of I1 and I2 as 394 kg ha−1, 53% higher). Interestingly, PY values were not significantly different in I1 and I2, but they were lower significantly in I3 by 28%, 27% and 20% in P1, P2, and P3, respectively. Essential plant characteristics including plant height, stem diameter, and panicle number were 6.1–16.7%, 6.4–24.5%, and 18.4–36.5% lower, respectively, in I2 and I3 than those in I1. The highest Leaf Area Index (LAI) value (5.34) was recorded in the in-furrow planting and I1, while the lowest value was observed in the on-ridge planting method and I3 (3.47). In I3, leaf temperature increased by an average of 2.5–3 oC, particularly during the anthesis stage. The results also showed that at a similar leaf water potential (LWP) higher yield and dry matter were obtained in the in-furrow planting compared to those obtained in the basin and on-ridge planting methods. The highest stomatal conductance (gs) value was observed within the in-furrow planting method and full irrigation (I1P3), while the lowest values were obtained in the on-ridge and 50%WR (I3P2). Finally, photosynthesis rate (An) reduction with diminishing LWP was mild, providing insights into quinoa’s adaptability to drought. In conclusion, considering the thorough evaluation of all the measured parameters, the study suggests using the in-furrow planting method with a 75%WR as the best approach for growing quinoa in arid and semi-arid regions to enhance production and resource efficiency.

Performance Test of Artificial Defoliating Broccoli Conveyor Line and Analysis of Defoliating Broccoli Inflorescences

There is a close relationship between stem and leaf biological characteristics of mature broccoli plants and defoliation technology. Morphological parameters such as the spread degree and diameter of cauliflower stem and leaf and the connection performance of cauliflower stem and leaf were studied. These experiments are helpful to the research of defoliation devices and methods for large-scale manual transportation lines. In this paper, according to the damage forms that may be suffered in the separation process of mature broccoli stems and leaves, “sunny” broccoli varieties were selected. Firstly, the mechanical properties of mature broccoli stems were obtained through different loading methods such as stretching, compression, shearing and bending. Secondly, the stress relaxation characteristics of broccoli were analyzed by static compression of broccoli flower balls. Finally, the separation method of broccoli stems and leaves was simulated by ANSYS. The simulation results showed that shear fracture was more suitable for stem and leaf separation of broccoli than tensile fracture. Then, aiming at the separation of stems and leaves of broccoli, an artificial broccoli assembly line was proposed to ensure the efficiency of leaf removal through man–machine cooperation. The dynamic characteristics of the belt of broccoli leaf removal line were studied to ensure the efficient and stable operation of the conveyor system of broccoli artificial leaf removal line.

Multi-scaling allometry in human development, mammalian morphology, and tree growth

Various animal and plant species exhibit allometric relationships among their respective traits, wherein one trait undergoes expansion as a power-law function of another due to constraints acting on growth processes. For instance, the acknowledged consensus posits that tree height scales with the two-thirds power of stem diameter. In the context of human development, it is posited that body weight scales with the second power of height. This prevalent allometric relationship derives its nomenclature from fitting two variables linearly within a logarithmic framework, thus giving rise to the term “power-law relationship.” Here, we challenge the conventional assumption that a singular power-law equation adequately encapsulates the allometric relationship between any two traits. We strategically leverage quantile regression analysis to demonstrate that the scaling exponent characterizing this power-law relationship is contingent upon the centile within these traits’ distributions. This observation fundamentally underscores the proposition that individuals occupying disparate segments of the distribution may employ distinct growth strategies, as indicated by distinct power-law exponents. We introduce the innovative concept of “multi-scale allometry” to encapsulate this newfound insight. Through a comprehensive reevaluation of (i) the height-weight relationship within a cohort comprising 7, 863, 520 Japanese children aged 5–17 years for which the age, sex, height, and weight were recorded as part of a national study, (ii) the stem-diameter-height and crown-radius-height relationships within an expansive sample of 498, 838 georeferenced and taxonomically standardized records of individual trees spanning diverse geographical locations, and (iii) the brain-size-body-size relationship within an extensive dataset encompassing 1, 552 mammalian species, we resolutely substantiate the viability of multi-scale allometric analysis. This empirical substantiation advocates a paradigm shift from uni-scaling to multi-scaling allometric modeling, thereby affording greater prominence to the inherent growth processes that underlie the morphological diversity evident throughout the living world.

Enhancing Leafy Vegetable Growth and Yield with Goat Urine, Moringa Leaf, and Banana Stem-based Liquid Organic Fertiliser

Pak choy and mustard greens are traditionally grown with many inorganic fertilisers, which can reduce soil fertility when applied frequently. The adoption of organic fertilisers offers a sustainable solution to this challenge. This study investigates the impact of liquid organic fertiliser (LOF) derived from goat urine, Moringa leaves, and banana stems on the growth and yield of pak choy and mustard greens. The research design employed a randomised complete block design with four treatments and ten replications. These treatments included a control group, 100% nitrogen, phosphorus, potassium (NPK, inorganic fertiliser), 100% LOF, and a 50% NPK + 50% LOF blend. The application of LOF, sourced from goat urine, Moringa leaves, and banana stems, demonstrated a significant influence on nearly all plant parameters. Notably, the 100% LOF treatment yielded the highest results for fresh leaf weight (26.46 g), fresh stalk weight (39.64 g), dry leaf weight (4.57 g), stem diameter (48.27 mm), Soil Plant Analysis Development value (SPAD, 40.73 units), plant height (31.59 cm), leaf width (8.45 cm), and leaf length (13.33 cm) for pak choy. Additionally, 100% LOF also produced the highest results for fresh leaf weight (21.34 g), dry root weight (0.31 g), stem diameter (21.53 mm), SPAD value (32.40 units), plant height (31.59 cm), leaf width (10.40 cm), and leaf length (15.65 cm) for mustard greens. This study demonstrates that a blend of goat urine, Moringa leaves, and banana stems can be used as a LOF that can replace inorganic NPK fertilisers in growing pak choy and mustard. It not only addresses issues with soil fertility but also contributes to environmentally friendly farming practices.

Impact of goat manure application on growth of wild watermelon under shade house cultivation

The continuous use of inorganic fertilizers in agriculture poses detrimental effects on soil health and future crop yields. Therefore, alternative sources of plant nutrients that are environmentally friendly and cost-effective for use in crop production, especially with the escalating cost of inorganic fertilizers, are necessary. A shade-house study was designed to determine the effect of different quantities of goat manure applications on growth attributes and yield of wild watermelon (Citrullus lanatus subsp.). A randomized complete block design (RCBD) was used to arrange the treatments, with fourteen (14) replications (n = 84). Six (6) treatments consisting of various quantities (v/v) of river sand, Hutton soil, and goat manure (T0 -1:3:0, T1 -1:3:1, T2 -1:3:2, T3 -1:3:3, T4 -1:3:4, and T5 -1:3:3) were used, with T0 -1:3:0 constituting the control. Treatments had a highly significant (P ≤ 0.01) effect on dry shoot mass (65%), fruit weight (75%), and fruit diameter (75%) except for the dry root mass (44%), vine length (47%), chlorophyll (47%), number of fruit (27%) and stem diameter (22%) of wild watermelon plants. Dry shoot mass was the highest (11.14 g) in T4 -1:3:4, and the lowest dry shoot mass (6.57 g) was obtained in T1 -1:3:1 when compared to the control. The fruit fresh weight of the wild watermelon was reduced in all the treatments, when compared to the control. The biggest fruit diameter (66.66 mm) was observed in T4 -1:3:4, and the lowest (14.4 mm) was observed in T5 -1:3:5. In conclusion, T4 -1:3:4 enhanced greater vegetative growth (dry shoot matter) and yield attributes (fruit diameter and weight) of the wild watermelon.

Tithonia diversifolia (Asteraceae) as a reservoir of natural enemies to promote pest control and improve development of tomato (Solanum lycopersicum) in open conditions

ABSTRACT Tithonia diversifolia has the potential for use as a reservoir for entomophages in pest control, as it attracts and preserves natural enemies before migrating to the target crop, where a high incidence of pests occurs. For example, in tomato crop production one of the limiting factors, under field condition, is the incidence of phytophagous insects. We determined the effects of Tithonia diversifolia on species assemblage structure of natural enemies and pest insects (abundance and diversity), plant growth (leaf area, stem length and diameter, number of leaves, flowers and fruits, and fruits weight/per plant), plant defense (leaf thickness and hardness) and fruit colouration on tomato plants in open conditions. Through direct and indirect samplings, a total of 456 insects were collected, comprising 76 natural enemies, 269 pests and 111 belonging other guilds. Length, stem diameter, number of flowers, leaf thickness, and hardness increased, while the number of leaves decreased. T. diversifolia plants increased natural enemies but not pest abundance in tomato plants, demonstrating that this plant can alter the structure of the insect community associated with tomato.

Effect of exogenous melatonin on growth and antioxidant system of pumpkin seedlings under waterlogging stress.

Melatonin regulates defense responses in plants under environmental stress. This study aimed to explore the impact of exogenous melatonin on the phenotype and physiology of 'BM1' pumpkin seedlings subjected to waterlogging stress. Waterlogging stress was induced following foliar spraying of melatonin at various concentrations (CK, 0, 10, 100, 200, and 300 μmol·L-1). The growth parameters, malondialdehyde (MDA) content, antioxidant enzyme activity, osmoregulatory substance levels, and other physiological indicators were assessed to elucidate the physiological mechanisms underlying the role of exogenous melatonin in mitigating waterlogging stress in pumpkin seedlings. The results indicate that pumpkin seedlings exhibit waterlogging symptoms, such as leaf wilting, water loss, edge chlorosis, and fading, under waterlogging stress conditions. Various growth indicators of the seedlings, including plant height, stem diameter, root length, fresh and dry weight, and leaf chlorophyll content, were significantly reduced. Moreover, the MDA content in leaves and roots increased significantly, along with elevated activities of superoxide dismutase, catalase, peroxidase, and soluble protein contents. When different concentrations of melatonin were sprayed on the leaves post waterlogging stress treatment, pumpkin seedlings showed varying degrees of recovery, with the 100 μmol·L-1 treatment displaying the best growth status and plant morphological phenotypes. There were no significant differences compared to the control group. Seedling growth indicators, chlorophyll content, root activity, antioxidant enzyme activities, soluble protein content, and osmotic adjustment substance content all increased to varying degrees with increasing melatonin concentration, peaking at 100 μmol·L-1. Melatonin also reduced membrane damage caused by oxidative stress and alleviated osmotic imbalance. Exogenous melatonin enhanced the activities of antioxidant enzymes and systems involved in scavenging reactive oxygen species, with 100 μmol·L-1 as the optimal concentration. These findings underscore the crucial role of exogenous melatonin in alleviating waterlogging stress in pumpkins. The findings of this study offer a theoretical framework and technical assistance for cultivating waterlogging-resistant pumpkins in practical settings. Additionally, it establishes a theoretical groundwork for the molecular breeding of pumpkins with increased tolerance to waterlogging.

Enhancing Iris tingitana cv. Wedgewood productivity with chemical, bio-fertilizers and irrigation

This study aimed to investigate the impact of various fertilization methods and doses on the growth, flowering, and chemical composition of Iris tingitana cv. Wedgewood plants. The research aimed to address challenges hindering Iris plant development and bulb production, ultimately striving to cultivate high-quality plants suitable for Egyptian conditions. Conducted over two seasons (2021-2022 and 2022-2023) at the Horticulture Research Institute’s nursery of the Agriculture Research Center in Giza, Egypt, the experiment followed a factorial design with a randomized complete design (RCD) and three replicates. Results revealed that plants treated with 5 g/pot of phosphorein and 2 g/pot of kristalon, with irrigation intervals every 10 days after sowing (DAS), exhibited superior growth parameters. These included increased vegetative growth in terms of height, stem length, number of leaves per plant, fresh weight of cut spikes, diameter of the spike stem, and earliest flowering compared to other treatments across both seasons. Conversely, the application of 2 g/pot of kristalon and nitrobine, combined with irrigation intervals every 10 DAS, ranked second in enhancing plant growth and flowering characteristics in both seasons.

Nocturnal LED Supplemental Lighting Improves Quality of Tomato Seedlings by Increasing Biomass Accumulation in a Controlled Environment

Tomato (Solanum lycopersicum L. cv. Zhongza NO. 9) was used as the experimental material to investigate the effects of nocturnal LED supplemental light with the photosynthetic photon flux density (PPFD) of 100, 200, 300 μmol·m−2·s−1, and the light time of 1, 2 h on the seedling quality in a controlled environment, with seedlings without nocturnal supplemental lighting serving as the control. The results demonstrate that an increase in PPFD at night progressively enhances the plant height and leaf number of tomato seedlings, while stem diameter and leaf area initially increase and subsequently decrease. Although light time and light period-of-time at night did not significantly affect seedling morphology, PPFD and light time notably influenced chlorophyll content and net photosynthetic rate. An optimal lighting energy amount at night augmented photosynthetic capacity. However, excessive PPFD induced photoinhibition in the leaves. Additionally, appropriate nocturnal LED supplemental lighting significantly improved the antioxidant capacity of the seedlings, increased proline content, reduced malondialdehyde content, and bolstered the self-protection mechanisms of the seedlings against nocturnal light stress. Both the PPFD and light time at night promoted biomass accumulation in tomato seedlings. Specifically, when supplemental lighting was applied for 2 h at an intensity of 200 μmol·m−2·s−1, both the fresh and dry weights of the shoot and root significantly increased, and the seedling health index was highest. Therefore, appropriate nocturnal LED supplemental lighting positively impacts the health index and photosynthate accumulation of tomato seedlings, but controlling PPFD is essential to avoid photoinhibition.

Water availability and accessions of Passiflora cincinnata Mast. can shape the communities of arbuscular mycorrhizal fungi

Understanding how water availability affects different caatinga passionfruit accessions (Passiflora cincinnata Mast.) and their drought tolerance is crucial for successful cultivation in semi-arid environments. Additionally, assessing the impact of this stress on arbuscular mycorrhizal fungi (AMF) communities' structure and dynamics is also essential. A greenhouse experiment was conducted with the purpose of identifying tolerant and sensitive P. cincinnata accessions under drought stress and how the water availability would affect AMF communities, which were taxonomically identified based on morphological characters. Results show that water availability influenced height, stem diameter, total chlorophyll, dry and fresh shoot biomass, fresh root biomass, leaf area, number of leaves and tendrils, and root/shoot ratio of accessions of P. cincinnata. However, water availability did not influence root dry biomass, only the identity of P. cincinnata accessions differed from each other. In the PCA-based ranking, based on the morpho-descriptors traits, and on the indices of drought stress tolerance, accessions 01 and 48 were considered tolerant and sensitive to drought, respectively. The abundance of glomerospores and the AMF richness are not influenced by the factors studied, but water availability has increased the frequency of mycorrhizal colonization, diversity, and evenness of AMF species, in addition to reducing its dominance. AMF communities’ composition was modulated by P. cincinnata accessions and by water availability. Utilizing morpho-agronomic traits, it becomes feasible to differentiate P. cincinnata accessions exhibiting tolerance and sensitivity to drought stress. Particular emphasis is placed on fresh and dry shoot biomass, leaf area, and height, each contributing approximately 12% to these outcomes. Changes on the composition of AMF communities after imposition of water deficit suggest that some AMF species may show some drought tolerance and that preferences for P. cincinnata genotypes may exist.

The alleviating effect on the growth, chlorophyll synthesis, and biochemical defense system in sunflowers under cadmium stress achieved through foliar application of humic acid

BackgroundWith the progress of industrialization and urbanization, cadmium (Cd) pollution in farmland is increasingly severe, greatly affecting human health. Sunflowers possess high resistance to Cd stress and great potential for phytoremediation of Cd-contaminated soil. Previous studies have shown that humic acid (HA) effectively mitigates plant damage induced by Cd; however, its alleviating effects on sunflower plants under Cd stress remain largely unknown.ResultsWe employed four different concentrations of HA (50, 100, 200, and 300 mg L−1) via foliar application to examine their ability to alleviate Cd stress on sunflower plants' growth, chlorophyll synthesis, and biochemical defense system. The results revealed that Cd stress not only reduced plant height, stem diameter, fresh and dry weight, and chlorophyll content in sunflower plants but also altered their chlorophyll fluorescence characteristics compared to the control group. After Cd stress, the photosynthetic structure was damaged and the number of PSII reactive centers per unit changed. Application of 200 mg L−1 HA promotes sunflower growth and increases chlorophyll content. HA significantly enhances antioxidant enzyme activities (SOD, POD, CAT, and APX) and reduces ROS content (O2−, H2O2 and −OH). Totally, Application of 200 mg L−1 HA had the best effect than other concentrations to alleviate the Cd-induced stress in sunflower plants.ConclusionsThe foliar application of certain HA concentration exhibited the most effective alleviation of Cd-induced stress on sunflower plants. It can enhance the light energy utilization and antioxidant enzyme activities, while reduce ROS contents in sunflower plants. These findings provide a theoretical basis for using HA to mitigate Cd stress in sunflowers.

Evaluation of Chemical and Biological Products for Control of Crown Gall on Rose.

Crown gall is a soil-borne bacterial disease caused by Agrobacterium tumefaciens, leading to significant economic losses in many plant species. For the assessment of the biological and chemical products on crown gall, each plant's crown region and roots were wounded, and then were dipped into their respective treatments. After the treatments, the plants were inoculated with a suspension of pathogenic A. tumefaciens isolate FBG1034 and maintained in a greenhouse for six months to assess them for gall formation. A quantitative real-time PCR assay was performed to quantify the A. tumefaciens using the chvE gene. Biological products such as the Agrobacterium radiobacter strain K1026, and strains 1 and 2, resulted in the lowest average root gall diameter and significantly reduced the crown gall diameter to stem diameter ratio, and the chemical product copper octanoate reduced the number of crown and root galls as well as the crown and root gall diameter compared to the inoculated, non-treated control. Moreover, both the A. radiobacter strain K1026 and strain 1 treatments resulted in an approximately 85% and 65% reduction in crown and root gall incidence, respectively, in both of the trials compared to the inoculated, non-treated plants. The findings of this study indicate that the use of biological and chemical products could help to suppress crown and root gall disease in rose plants.

Exploring Polybag Size, Nursery Mixtures and Rootstocks for Optimizing Lasoda (Cordia myxa L.) Nursery Techniques

Background: Lasoda (Cordia myxa L.) is lesser utilized fruit plant species suitable for growing in large parts of arid and semi-arid regions of India. Besides the economic importance of its fruits in the vegetable and pickle industry, this species is also known for ethnomedicinal properties in different plant parts. In order to utilize it to its fullest potential, standardization of nursery technology for mass multiplication by vegetative propagation method is a necessary step. With the above background in the view, an experiment was conducted to see the effect of polybag size, nursery mixture and rootstock on seed germination, growth of seedlings after germination, budding success and growth of budded plants. Methods: The study was conducted during June-September, 2020. The treatment comprised of two polybag sizes, six nursery media compositions and two kinds of rootstocks. The observations were recorded on seed germination, seedling growth, days to bud sprout after budding, budding success and shoot length and diameter after 30 days of budding. Result: The main effects of nursery mixture revealed that plant height, stem diameter, number of leaves, shoot length and shoot diameter after budding were significantly affected by nursery mixture composition. The highest plant height (29.53 cm) recorded in the M4 mixture was significantly higher over M1, M2 and M3 but the differences were non-significant when compared with M5 and M6. A similar trend was also recorded in the case of stem diameter and number of leaves which showed significantly higher values in M4, M5 and M6 as compared to M1, M2 and M3. The highest shoot length (8.34 cm) and shoot diameter (3.40 mm) were recorded in M5 and M4 which were significantly higher than most of other media levels.

Piriformospora indica alleviates soda saline-alkaline stress in Glycine max by modulating plant metabolism.

Soil salinization is one of the major factors limiting agricultural production. Utilizing beneficial microorganisms like Piriformospora indica (P. indica) to enhance plant tolerance to abiotic stresses is a highly effective method, but the influence of P. indica on the growth of soybean in natural saline-alkaline soil remains unclear. Therefore, we investigated the effects of non-inoculation, P. indica inoculation, and fertilization on the growth, antioxidant defense, osmotic adjustment, and photosynthetic gas exchange parameters of soybean under two different levels of saline-alkaline stress in non-sterilized natural saline-alkaline soil. The study found that: 1) P. indica inoculation significantly promoted soybean growth, increasing plant height, root length, and biomass. Under mildly saline-alkaline stress, the increases were 11.5%, 16.0%, and 14.8%, respectively, compared to non-inoculated treatment. Under higher stress, P. indica inoculation achieved the same level of biomass increase as fertilization, while fertilization only significantly improved stem diameter. 2) Under saline-alkaline stress, P. indica inoculation significantly increased antioxidant enzyme activities and reduced malondialdehyde (MDA) content. Under mildly stress, MDA content was reduced by 47.1% and 43.3% compared to non-inoculated and fertilized treatments, respectively. Under moderate stress, the MDA content in the inoculated group was reduced by 29.9% and 36.6% compared to non-inoculated and fertilized treatments, respectively. Fertilization only had a positive effect on peroxidase (POD) activity. 3) P. indica inoculation induced plants to produce more osmotic adjustment substances. Under mildly stress, proline, soluble sugars, and soluble proteins were increased by 345.7%, 104.4%, and 6.9%, respectively, compared to non-inoculated treatment. Under higher stress, the increases were 75.4%, 179.7%, and 12.6%, respectively. Fertilization had no significant positive effect on proline content. 4) With increasing stress, soybean photosynthetic capacity in the P. indica-inoculated treatment was significantly higher than in the non-inoculated treatment, with net photosynthetic rate increased by 14.8% and 37.0% under different stress levels. These results indicate that P. indica can enhance soybean's adaptive ability to saline-alkaline stress by regulating ROS scavenging capacity, osmotic adjustment substance content, and photosynthetic capacity, thereby promoting plant growth. This suggests that P. indica has great potential in improving soybean productivity in natural saline-alkaline soils.