Leaf Number Research Articles

Influence of Aloe Vera Gel on Germination and Early Growth of Tomato (Solanum lycopersicum) Seedlings in the Nursery

Tomato (Solanum lycopersicum L.) nursery production often relies heavily on chemical inputs to ensure vigorous seedling growth, which may have environmental and economic drawbacks. This study aimed to evaluate the efficacy of Aloe vera gel as a natural alternative to chemical treatments for improving germination and early seedling growth of Cobra 26 tomato seeds. The study used a factorial block design to compare the effects of seed treatments (Aloe vera gel coating, mancozeb, and untreated control) and substrate types (unfertilised topsoil, NPK-fertilised topsoil, and Aloe vera gel mixed with topsoil) on seed germination and seedling growth over three nursery cycles. Seeds coated with Aloe vera gel demonstrated the highest germination rate (90.53%) and fastest germination time (3 days), outperforming both mancozeb-treated and control seeds in germination kinetics. Growth parameters such as seedling height and leaf number were significantly influenced by substrate type (p<0.03), with no notable differences between NPK and Aloe vera-treated substrates. The study suggests that Aloe vera gel, both as a seed coating and soil additive, offers a promising, eco-friendly alternative to chemical treatments, enhancing seed germination and early seedling growth in tomatoes

An automated phenotyping method for Chinese Cymbidium seedlings based on 3D point cloud

Aiming at the problems of low efficiency and high cost in determining the phenotypic parameters of Cymbidium seedlings by artificial approaches, this study proposed a fully automated measurement scheme for some phenotypic parameters based on point cloud. The key point or difficulty is to design a segmentation method for individual tillers according to the morphology-specific structure. After determining the branch points, two rounds of segmentation schemes were designed. The non-overlapping part of each tiller and the overlapping parts of each ramet are separated in the first round based on the edge point cloud-based segmentation, while in the second round, the overlapping part was sliced along the horizontal direction according to the weight ratio of the tillers above, to obtain the complete point cloud of all tillers. The core superiority of the algorithm is that the segmentation fits the tiller growth direction well, and the extracted skeleton points of tillers are close to the actual growth direction, significantly improving the prediction accuracy of the subsequent phenotypic parameters. Five phenotypic parameters, plant height, leaf number, leaf length, leaf width and leaf area, were automatically calculated. Through experiments, the accuracy of the five parameters reached 98.6%, 100%, 92.2%, 89.1%, and 82.3%, respectively, which reach the needs of various phenotypic applications.

Assessment of genetic diversity among Ixora genotypes through morphological and RAPD molecular marker analysis

Ixora a genus in the Rubiaceae family commonly known as jungle geranium, was the focus of the study. However, classifying Ixora species has been challenging due to environmental influences on phenotypic traits. This study explores the genetic diversity and morphological traits of 11 Ixora genotypes from various regions in India using 15 RAPD markers and morphological assessments. A total of 210 bands were generated, Unweighted Pair Group Method for Arithmetic Average (UPGMA) Cluster analysis revealed significant genetic relationships among the genotypes. Notably, Genotypes 9, 10 and 11 shared similar banding patterns with marker OPF 02, while Genotypes 4 and 7, despite differing growth habits, showed close genetic ties and shared RAPD markers OPA03 and OPE04. A unique marker (OPA03 - 340 bp) was identified exclusively in Genotype 4. Principal Component Analysis (PCA) indicated that 2 principal components explained 77.074 % of the total variance, highlighting plant height and leaf number as significant traits. Heat map clustering further illustrated phenotypic variability, grouping genotypes based on morphological similarities. This study demonstrates the utility of RAPD markers in distinguishing Ixora genotypes and provides valuable insights into morphological traits, guiding future breeding programs and genetic research.

Performance Evaluation of Hydroponic Grow-Outs in An Innovative Coldwater Aquaponic System Featuring Rainbow Trout and Lettuce

A 45-day trial was carried out to assess the production performance of different hydroponic media in a novel do-it-yourself (DIY) low-tech re-circulating aquaponic system for temperate regions with rainbow trout (Oncorhynchus mykiss) and lettuce (Lactuca sativa). Rainbow trout juveniles (average weight of 35.59 g) were stocked in the experimental units at 2.8 kg.m-3 and fed with commercial floating pelleted feed at 8 % of their body weight in three treatments and a control. The lettuce saplings were randomly planted in the river stone bed (T1), crushed stone bed (T2), raft/deep water culture (DWC) unit (T3) and control (C) soil bed (fortified with NPK fertiliser) with equivalent planting intervals of 42 saplings.m-2. The system, designed with low-tech simplicity, was managed without alkalinity correction and depended entirely on plant growth and metabolism for biofiltration. The water quality parameters such as temperature, pH, dissolved oxygen (DO), dissolved free CO2, hardness, total alkalinity, ammonium, nitrite, and nitrate varied significantly (P < 0.05) among the treatments compared to the control. The final individual weight, biomass gain, specific growth rate (SGR), and feed conversion ratio (FCR) of rainbow trout were significantly better (P < 0.05) in media beds (crushed stone and river stone) compared to control and DWC systems. The final mean weights of rainbow trout in river stone (12.33 ± 0.002 g and crushed stone (12.39 ± 0.054 g) treatments were significantly higher (P < 0.05) than in DWC (12.1 ± 0.023 g) and control (12.09 ± 0.002 g) treatments. The production of lettuce was significantly greater (P < 0.05) in all three treatments (river stone: 4.33 ± 0.123 g, crushed stone: 4.53 ± 0.09 g and DWC: 4.31 ± 0.163 g) compared to the control (3.31 ± 0.172 g). The DWC including the media bed systems facilitates the improved performance of lettuce saplings in terms of final height and leaf number. These results show that a low-tech media bed system without a supplementary biofiltration unit can achieve sustainable production of both fish and vegetables in temperate hilly terrains.

Genetic Variability, Character Association and Path Analysis for Yield and Yield Components in Foxtail Millet [Setaria italica (L.) P. Beauv.] Accessions under Multi Environments in Foothills of Nagaland

Background: Foxtail millet cultivation inIndia’s North Eastern Hill regionholds promise due to its adaptation to diverse environments and high-quality grain. The objective of this study was to assess the amount of variability present among the genotypes, association of traits and find out foxtail millet genotypes that produce high yield in diverse environments. Methods: The investigation was carried out during July 2022 to May 2023 in four different dates of sowing. Two environments maintained under rainfed condition and the remaining two environments are maintained under irrigated condition. The experiment was conducted in randomized complete block design with three replications in all environments. Result: Analysis of variance revealed statistically significant differences (at 5%) among the 30 genotypes for all yield variables under evaluation. Genotype ‘G1’ exhibited superior performance for both yield and yield-related traits. The present study revealed considerable genetic variation among the yield traits, with all traits demonstrating high heritability except for harvest index.Traits such as fodder yield per plant, panicle length, biological yield, flag leaf width, peduncle length, panicle width and grain yield per plant show high heritability coupled with high genetic advance. A strong correlation was observed between grain yield per plant and several traits including days to 50% flowering, days to maturity, plant height, panicle length, flag leaf length, peduncle length, biological yield and fodder yield per plant. This correlation was consistent at both the genotypic and phenotypic levels. Biological yield exhibited the strongest direct influence on grain yield per plant, followed by harvest index, flag leaf width and number of base tillers on genotypic and phenotypic levels.

Performance of the edible halophyte Cakile maritima under critical magnesium and potassium thresholds

In their natural biotope, plants are challenged with low nutrient availability which is one of the most important limiting factors for plant production. Nutrient limitation causes disruption in several metabolic pathways resulting in a decrease in plant growth and establishment. Such responses were mostly studied in glycophytes while in halophytes the data remained scare. In the present investigation, using Cakile maritima as a plant model for halophytes, we attempt to elucidate the behavior of this species under critical magnesium and potassium thresholds. Our data showed that low K or Mg supply (0.01 mM) reduced leaf number and biomass production in leaves, stems and roots while both parameters were improved at 0.05 mM Mg and K concentration before reaching an optimum at 0.25 mM Mg and 1 mM K, respectively. Several indices of K and Mg stress tolerance were reduced upon deficiency in both elements and were significantly improved by moderate K and Mg supply. Photosynthetic pigment content was reduced upon both deficiencies with the highest reductions recorded in plants suffering from severe Mg and K starvation. Increasing Mg and K supply resulted in better chlorophyll synthesis as reflected by the increase in chlorophyll stability index parameter (CSI). Furthermore, both deficiencies triggered oxidative damages as malondialdehyde content (MDA) and electrolyte leakage (EL) increased while membrane stability index (MSI) decreased under both deficiencies. Such results suggested that the cell redox homeostasis was altered when Mg and K were omitted from the nutrient solution. Interestingly, moderate and high Mg and K concentrations promoted C. maritima growth and reduced the oxidative damage caused by the lack of both elements in the external medium. Overall, C. maritima exhibited a typical halophytic behaviour, requiring less macroelements to express its growth performance when cultivated under critical magnesium and potassium thresholds.

Functional characterisation of BnaA02.TOP1α and BnaC02.TOP1α involved in true leaf biomass accumulation in Brassica napus L.

Leaves, as primary photosynthetic organs essential for high crop yield and quality, have attracted significant attention. The functions of DNA topoisomerase 1α (TOP1α) in various biological processes, including leaf development, in Brassica napus remain unknown. Here, four paralogs of BnaTOP1α, namely BnaA01.TOP1α, BnaA02.TOP1α, BnaC01.TOP1α and BnaC02.TOP1α, were identified and cloned in the B. napus inbred line 'K407'. Expression pattern analysis revealed that BnaA02.TOP1α and BnaC02.TOP1α, but not BnaA01.TOP1α and BnaC01.TOP1α, were persistently and highly expressed in B. napus true leaves. Preliminary analysis in Arabidopsis thaliana revealed that BnaA02.TOP1α and BnaC02.TOP1α paralogs, but not BnaA01.TOP1α and BnaC01.TOP1α, performed biological functions. Targeted mutations of four BnaTOP1α paralogs in B. napus using the CRISPR-Cas9 system revealed that BnaA02.TOP1α and BnaC02.TOP1α served as functional paralogs and redundantly promoted true leaf number and size, thereby promoting true leaf biomass accumulation. Moreover, BnaA02.TOP1α modulated the levels of endogenous gibberellins, cytokinins and auxins by indirectly regulating several genes related to their metabolism processes. BnaA02.TOP1α directly activated BnaA03.CCS52A2 and BnaC09.AN3 by facilitating the recruitment of RNA polymerase II and modulating H3K27me3, H3K36me2 and H3K36me3 levels at these loci and indirectly activated the BnaA08.PARL1 expression, thereby positively controlling the true leaf size in B. napus. Additionally, BnaA02.TOP1α indirectly activated the BnaA07.PIN1 expression to positively regulate the true leaf number. These results reveal the important functions of BnaTOP1α and provide insights into the regulatory network controlling true leaf biomass accumulation in B. napus.

Optimizing Sour Orange Growth and Chemical Properties through Foliar Application of Nano and Organic Fertilizers

This study, conducted at the Lath House of Agriculture College, Al-Qasim Green University during the 2021-2022 growth season, aimed to evaluate the effects of KHARZA nanoparticles (NPs) and organic fertilizer (Nutirgreen) on sour orange seedlings. Different concentrations of KHARZA NPs (0, 1, 2, and 3 g L-1) and organic fertilizer (0, 1.5, 3, and 4.5 ml L-1) were applied. The experimental design followed a randomized complete block design (RCBD) with two factors, each having four treatments, and each treatment replicated thrice. Our findings reveal that spraying KHARZA NPs at a concentration of 3 g.L-1 significantly enhanced various vegetative parameters, such as plant height, stem diameter, leaf number, and leaf area, alongside improvements in chemical properties such as mineral concentration, chlorophyll content, and carbohydrate levels in leaves. Similarly, applying organic fertilizer at a rate of 4.5 ml L-1 led to notable enhancements in both vegetative and chemical characteristics compared to the control group. Notably, combined application of KHARZA NPs at 3 g L-1 and organic fertilizer at 4.5 ml L-1 resulted in synergistic effects, yielding the most favorable outcomes in terms of vegetative growth and chemical properties. These results underscore the potential of utilizing KHARZA nanoparticles and organic fertilizers in enhancing the growth and physiological properties of sour orange seedlings, offering promising avenues for sustainable agricultural practices. Keywords: Optimizing, spray nutrients, KHARZA, organic fertilizer, growth, orange seedlings

Chlamydomonas sp. extract meliorates the growth and physiological responses of 'Camarosa' strawberry (Fragaria × ananassa Duch) under salinity stress.

Microalgae like Chlamydomonas are beneficial organisms employed as biological stimulants to improve plants' growth, fruit quality, and stress tolerance. In the current study, the effects of Chlamydomonas sp. foliar spraying (0, 20, and 40 ml L-1) were assayed on Camarosa strawberry plants under salinity stress (0, 40, and 80 mM NaCl). The results showed that the foliar application of Chlamydomonas extract influenced strawberry's morphological, physiological, and biochemical characteristics under salinity stress. Foliar treatment of Chlamydomonas extract with and without salinity stress increased the leaf number and leaf area, the leaf relative water content, and photosynthetic pigments content. Moreover, the foliar application of Chlamydomonas extract decreased lipid peroxidation and hydrogen peroxide content and, on the other hand, enhanced the antioxidant enzymes activity (superoxide dismutase, guaiacol peroxidase, and peroxidase), phenolics, flavonoids, and anthocyanins content under salinity stress. For instance, the highest total antioxidant capacity was found in the plants foliar treated with 40 ml L-1of Chlamydomonas algae extract under 80 mM salinity stress, which increased by 102.4% compared to the controls, as well as the highest total phenolic compounds and anthocyanin's content were 30.22, and 7.2% more than the control plants, respectively. Overall, the foliar application of Chlamydomonas algae extracts, especially at a concentration of 20 ml L-1enhanced the strawberry's growth, yield, and physiological traits under saline conditions. The results with more detailed evaluations will be advisable for the pioneer farmers and extension section.

Leaf Number Index: a Ready Reckoner to Identify the Reproductive Stage for Nutrition of Six Maize (Zea Mays L.) Hybrids

Field experiments were carried to study the leaf number index of maize hybrids to identify the reproductive stage of six maize hybrids for application of nutrition at suitable time to improve more production was under taken at the Agricultural College farm, Bapatla during two consecutive years during rabi 2016-17 and 2017-18. The experiment was laid out in randomized block design with six maize hybrids as treatments in four replications. During both the seasons, tassel primordial initiation coincide with the 9th visible leaf in 900 M Gold and DKC 9081, 10th visible leaf in DKC 9142 and Pinnacle and 11th visible leaf in DKC 9120 and DKC 9042 with LNI of 54.54, 54.54, 53.77, 52.79, 54.62 and 54.62 respectively in first season and 53.70, 54.71, 51.85, 53.70, 55.55 and 54.71 respectively in second season.

Tropospheric ozone pollution: Implication for food security and crop nutrition in South Asia

The study was conducted on ambient ozone (O3), the most phyto-toxic air pollutant, and its effects on the growth and quality of okra (Abelmoschus esculentus) and peas (Pisum sativaum) grown in Northern Pakistan during the summer and winter of 2018. Okra was subjected to ambient O3 levels ranging from 43 to 63 ppb during the summer, with a mean O3 concentration of 55 ppb, while peas experienced lower winter concentrations of 15–25 ppb, with a mean O3 concentration of 19 ppb. The results indicated significant impacts on the growth and nutritional quality of crops, especially okra. Anti-ozonant ethylene diurea (EDU) was used for soil drenching to protect okra and green peas from O3 damage. Okra showed notable enhancements of 20%, 20%, 29%, and 13% in ash, protein, fiber, and non-fiber carbohydrates (NFE), respectively. Increase in plant height, leaf numbers, pod length, and dry weight was observed in EDU-treated okra plants. Conversely, peas exhibited less variation, although melioration was observed in plant height, pod numbers, length, and weight with EDU treatment. It was concluded that the concentration of ambient O3 in Peshawar is toxic enough to cause significant damage to crop growth and production. The stark difference in O3 impact during different seasons suggests that higher summer concentrations could severely compromise crop quality. This elicits significant concerns regarding food security in South Asia, especially for summer crops that can jeopardize future food security. It is recommended that further research be conducted on the effects of O3 on other regional crops to assess fully its implications for agricultural sustainability in the area.

Determination of fertilizer requirement of Indonesian black rice in winter season under different plant spacing at Agro-ecological Zone-9 of Bangladesh

Indonesian black rice is quite popular for its highly nutritive value and profitable production. The distinct knowledge about optimum fertilizer doses and plant spacing contributes to its promising yield. The experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh, from December 2022 to May 2023 to find out the effect of fertilizer management and plant spacing on the growth and yield of Indonesian black rice in the winter season. The experiment was conducted with 5 treatments of fertilizer management viz., F1(70% of recommended doses); F2(80% of recommended doses); F3(90% of recommended doses); F4(100% of recommended doses) and F5(110% of recommended doses) with 4 plants spacing viz., S1(20 cm × 15 cm); S2(20 cm × 20 cm); S3(25 cm × 15 cm) and S4(25 cm × 20 cm). The experiment was laid out in a split-plot design where the fertilizer management was allocated in main plots and the plant spacing was distributed in sub-plots with three replications. The result revealed that the fertilizer doses and plant spacings along with the interaction effects significantly influenced the growth and yield parameters of Indonesian black rice. Regarding vegetative growth, plant height (79.3cm), total tiller plant-1(21.27cm), and total leaf number plant-1 (58.47) were maximal at 100% recommended dose of fertilizer(F4) at DAT 65. Similarly, S2(20 cm × 20 cm) had better result in crop growth and yield attributes. The interaction effects of the treatments showed significant impact on plant height, total tiller and leaf number where F4S2 gave satisfied results. The highest values for the yield parameters including the maximum number of grains panicle-1 (100.70), 1000-grain weight (28.33g), and grain yield (5.69g) were found from the combination treatment of F4S2. On the other hand, the lowest grain (3.68g) yield was found from F1S4. Therefore, observing the results of the experiment, the best consideration was F4S2 at Agro-ecological Zone-9 in the winter season for the desirable growth and yield of Indonesian black rice.

Treatment of cauliflower seeds with product based on bacillus subtilis aiming plant seedling production, development and productivity.

The relation between seed vigor and field performance is not yet fully understood, and it is questionable whether these effects extend to more advanced phenological stages and if they affect crop production. In front of that, the objective of this study was to evaluate the effects on the seedlings and plant production of cauliflower using doses of product based on Bacillus subtilis in seed treatment. The study was conducted in Ilha Solteira city, São Paulo State. The experimental design was a complete randomized design for laboratory analysis and complete randomized blocks for the field stage. Ten treatments were studied in a 2 x 5 factorial scheme with four replications. The treatments consisted of seed treatment of cultivars Sharon and Barcelona with Bacillus subtilis-based product (strain FMT001 containing 3x108 cells cm-3) in five doses (0, 100, 200, 300 and 400 mL per 10 kg of seeds). Seed vigor and crop yield (shoot, root and inflorescence weight, leaf number, inflorescence diameter and yield) characteristics were evaluated. Cultivars averages were compared by Tukey test (p <0.05) and regression for the doses. The results showed that doses of 200 and 400 mL per 10 kg of seeds increased the percentage of strong seedlings of cultivars Barcelona and Sharon, respectively.

Effects of water level gradients on the physiological ecology of Potamogeton crispus

Water level is crucial to the growth and development of wetland plants, in order to study the physiological and ecological responses of Pomatogeton crispus under different water levels, in the study, P. crispus were placed under 50 cm (control) and 60–135 cm water levels following a 15 cm gap gradient for 60 days in a simulation experiment. The results showed that: (1) As the water level gradient increased, the plant height, leaf number and biomass of P. crispus showed a trend of increasing and then decreasing. (2) The concentrations of chlorophyll a (Chl-a), chlorophyll b (Chl-b), chlorophyll a + b (Chl a + b) and carotenoids (Car) showed a multi-peak increasing trend with increasing water level, with the maximum values occurring in the 135 cm water level group. (3) The antioxidant enzymes of P. crispus showed a fluctuating upward trend with increasing water level, and the higher the water level the greater the difference within the group, and rooting activity of P. crispus was significantly increased under elevated water level conditions. (4) The P. crispus grows best in the water level range of 105 ∼ 120 cm, and the growth indexes such as the number of leaves and biomass all reach higher values in the water level of 105 ∼ 120 cm, If the water level is too high or too low, it has an effect on the growth and development of P. crispus.

Growth and Yield Performance of Mustard and Rapeseed Varieties as Influenced by Different Sowing Techniques

An experiment was conducted at the Agronomy field, Sher-e-Bangla Agricultural University, Dhaka, from November 2013 to February 2014 to investigate mustard and rapeseed varieties' growth and yield performances influenced by different sowing techniques. The experiment was laid out in a factorial randomized complete block design (RCBD) with three replications. The four varieties were BARI Sarisha-11, BARI Sarisha-13, BARI Sarisha-15, SAU Sarisha 2 (V1, V2, V3, and V4 respectively) and sowing techniques included broadcasting, line Sowing, raised bed, system of mustard intensification (SMI) (S1, S2, S3, and S4 respectively). Results showed that the highest plant height (143.58 cm) was achieved at the combination of BARI Sarisha-11 and the raised bed technique (V1S3) at harvest. Though the highest leaf number varied in different varieties, it was produced by the SMI technique. BARI Sarisha-15 and the SMI techniques produced the highest number of primary branches, though BARI Sarisha-11 produced the maximum secondary branches with the same technique. BARI Sarisha-11 performed best at all the DAS regarding dry matter accumulation (g) and the values resulting in 1.07, 11.44, 21.3, and 25.87g. SMI also proved to be the best, except for 30 DAS. The highest seed yield (3.74 t ha−1 and 3.80 t ha−1) was obtained using BARI Sarisha-11 and SMI techniques, respectively. The highest biological yields (12.80 t ha−1 and 12.86 t ha−1) were obtained by BARI Sarisha-11 and SMI technique, respectively. However, the maximum harvest index (34.84% and 32.45%) and highest oil percentages (40.65% and 41.38%) were obtained by BARI Sarisha-15 and line sowing, respectively. As such the var. BARI Sarisha-11 could be expected good yield following the SMI technique Bangladesh Agron. J. 2024, 26(2): 86-99

Non-thermal plasma enhances growth and salinity tolerance of bok choy (Brassica rapa subsp. chinensis) in hydroponic culture.

In this study, we aimed to examine the growth, physiological and biochemical status, and responses to salinity stress of bok choy (Brassica rapa subsp. chinensis) cultivated in a hydroponic system with a plasma-treated solution. Plasma gas generated using a cylindrical dielectric barrier discharge or air (control) was injected into Hoagland nutrient solution once a week for different durations (0, 5, and 10 min). After 4 weeks, the length of the shoots and roots, number of leaves, and dry weight of bok choy plants significantly increased in individuals grown with Hoagland solution treated with plasma gas for 10 min. An increase in dry weight of individual plants of approximately 80.5% was observed in plants in the plasma-treated group compared to those in a control group. The levels of chlorophyll, total soluble proteins, and nitrogen uptake, and transcription of genes related to salinity stress tolerance-WRKY2, HHP3, and ABI1- were also significantly elevated in bok choy grown with plasma treated Hoagland solution. Moreover, when exposed to 20 mM NaCl, plant length and leaf number were significantly increased, in the group grown with Hoagland solution treated with plasma gas for 10 min. Level of H2O2 was significantly elevated in the treated nutrient solutions. In plants grown with the treated nutrient solution, intracellular NO was highly detected in the cell division and elongation zone of roots. Our findings suggest that plasma treatment of nutrient solutions in hydroponic culture systems may improve the growth, physiological and biochemical status, and tolerance to salinity stress in plants, and a crucial role of H2O2 generated in the treated nutrient solutions may play in this improvement.

Purslane (Portulaca oleracea L.) Growth, Nutritional, and Antioxidant Status under Different Nitrogen Levels in Hydroponics

Purslane (Portulaca oleracea L.) is a common weed that attracts research and agricultural attention because of its significant nutritional value, and it is used commercially. The present work rated the effect of different nitrogen (N) concentrations, i.e., N50: 50 mg L−1; N100: 100 mg L−1; N200: 200 mg L−1; and N300: 300 mg L−1, on the growth, physiology, antioxidant capacity, and nutrient accumulation in the different plant parts of hydroponically grown purslane. Seedlings were transplanted to a Nutrient Film Technique (NFT) system and exposed to different N levels. The plants grown in high N levels of 300 mg L−1 had decreased biomass production, leaf number, leaf stomatal conductance, and total flavonoid content because of the increased oxidative stress, as shown by the elevated lipid peroxidation levels. Several enzymatic (superoxide dismutase) and non-enzymatic (ascorbic acid, total phenolics) plant antioxidant activities were activated to counteract the oxidative factors. Plants grown in intermediate N levels in the NS (i.e., 100 mg L−1) had decreased oxidative stress as several enzymatic antioxidant activities, i.e., peroxidases and catalases, were increased. Additionally, the water use efficiency and nitrogen uptake, as well as leaf stomatal conductance and leaf chlorophyll fluorescence, were increased in plants grown at a N level of 200 mg L−1. The mineral accumulation in the leaves, stems, and roots fluctuated, with increased calcium, magnesium, and sodium content being observed in the plants grown at high N levels in the nutrient solution. The stems accumulated less N compared with the leaves, but the N content and accumulation rates in purslane leaves were not affected by the N levels in the nutrient solution. Therefore, to increase the yield, nutritional value, and water use efficiency of purslane that is grown hydroponically, a concentration of 200 mg L−1 N in the nutrient solution is recommended.

Effects of mulch films with different thicknesses on the microbial community of tobacco rhizosphere soil in Yunnan laterite.

The mulch film (MF) management model of the agricultural field affects the physical and chemical properties of soil (PCPS) and the structure of the microorganism community; however, studies on the relationship between the rhizosphere microorganism community structure and the thickness of MF are still limited. To understand the interactions among the MF thickness, PCPS, and rhizosphere microorganism, a study was conducted by using an integrated metagenomic strategy, where tobacco rhizosphere soil was treated with four commonly representative and used thicknesses of MFs (0.004, 0.006, 0.008, and 0.010 mm) in Yunnan laterite. The results showed that agronomic traits such as the tobacco plant height (TPH), leaf number (LN), fresh leaf weight (FLW), and dry leaf weight (DLW) were significantly (p < 0.01) improved in the field mulched with the thickest film (0.010 mm) compared with the exposed field (CK), and there was a 6.81 and 5.54% increase in the FLW and TPH, separately. The correlation analyses revealed a significant positive correlation of the MF thickness with the soil water content (SWC), soil organic matter (SOM), total nitrogen (TN), available nitrogen (AN), total phosphorus (TP), and available phosphorus (AP; all p < 0.01), while the MF thickness was negatively correlated with the soil temperature (ST; p < 0.01). In addition, the community structure of the rhizosphere soil bacteria was significantly changed overall by the MF thickness, which also interfered with the function of the rhizosphere soil bacteria. The correlation analyses also showed that the abundance of Bradyrhizobium and Nitrospira was positively correlated with the MF thickness, while the abundance of Sphinsinomonas and Massilia was negatively correlated with it. This indicated that with the increase of the MF thickness, the ability of the rhizosphere soil to utilize N and remove harmful molecules was strengthened, while the capacity of the rhizosphere soil to degrade pollutants was greatly reduced. These findings provide additional insights into the potential risks of the application of different thicknesses of MFs, particularly concerning the PCPS and soil microbial communities.

Effects of turfgrass canopy shade levels and quantum spectrum on the germination and development of smooth crabgrass (Digitaria ischaemum)

AbstractSmooth crabgrass [Digitaria ischaemum (Schreb.) Schreb. ex Muhl.] is one of the most troublesome summer annual weeds in cool‐season turfgrass. Field experiments demonstrated a strong relationship between spring photosynthetic active radiation reaching the soil surface and the resulting smooth crabgrass cover in Kentucky bluegrass (Poa pratensis L.) 2/3 months later in summer. Both smooth crabgrass and canopy penetrating light were consistently reduced by higher mowing heights. Follow‐up experiments in controlled environments were initiated to improve our understanding of how light quality and quantity influence smooth crabgrass germination and growth. Smooth crabgrass germination was ≥99% following exposure to blue, red (R), far red (FR), both R and FR light pulses, or complete darkness treatments. A second germination experiment examined six levels of turfgrass canopy shade (0%, 24%, 44%, 77%, 90%, and 100% photosynthetic photon flux density [PPFD] reduction) and found that smooth crabgrass germination was ≥99% for all treatments. These experiments indicate that light quality and quantity do not affect smooth crabgrass germination. A greenhouse experiment examined five levels of turfgrass canopy shade (0%, 44%, 59%, 81%, and 91% PPFD reduction). Smooth crabgrass quantum and PSII (Photosystem II) operating efficiency increased in response to shade, while leaf number and thickness, specific leaf weight, tillering, mass, electron transport rate, and stomatal conductance decreased with increasing shade. Overall, the results demonstrate that smooth crabgrass is able to germinate regardless of canopy density, but seedling growth, development, and plant function are diminished in a dense turfgrass canopy shade.

Pearl millet phenology assessment: An integration of field, a review, and in silico approach

AbstractPearl millet [Pennisetum glaucum (L.) R.Br.] is an essential subsistence cereal for food security in dryland farming systems of the semiarid tropics (e.g., in sub‐Saharan Africa) and has improved tolerance to drought, heat, and salinity stress compared to other domesticated cereals. Assessing the variation on phenology is critical toward devising effective adaptative management strategies for crop adaptation to current and future climate change. In this context, pearl millet presents a vast genetic diversity, exhibiting sensitivity to temperature and photoperiod. Hence, this study aims to describe the genotypic variability in the phenological responses of pearl millet to temperature and photoperiod, particularly affecting leaf number with implications on the overall total time to flowering. The dataset encompassed 21 publications from seven countries, with experiments conducted from 1965 to 2023, including three field studies from the United States. Broad variability has been reported for phyllochron values ranging from 45 to 111°Cd leaf−1, with a mean value of 67°Cd leaf−1. Thermal time to panicle initiation ranged from 340 to 594°C, but no response to photoperiod duration was found due to the nature of dataset. Maximum number of leaves per shoot ranged from 11 to 25, showing response (1.55–2.15 leaf h−1) to photoperiod due to variations in thermal time to flowering (from 875 to 1346°Cd). Thermal time to flowering increased ca. 323°Cd h−1 under day durations longer than 13.3 h, below which basic vegetative phase duration was close to 1033°Cd. Based on the Agricultural Production Systems sIMulator simulations, different combinations of the above responses (in silico cultivars) generated a great range of times to flowering (44–120 days) for locations in Senegal, Brazil, India, and United States. The findings of this study can help breeders to explore the phenological genetic variability of pearl millet and provide inputs for crop growth models to evaluate future in silico scenarios.