Shoot Fresh Biomass Research Articles

Biochemical repercussions of light spectra on nitrogen metabolism in spinach (Spinacia oleracea) under a controlled environment.

Selecting appropriate light spectra of light-emitting diodes (LEDs) and optimal nutrient composition fertilizers has become integral to commercial controlled environment agriculture (CEA) platforms. This study explored the impact of three LED light regimes (BR: Blue17%, Green 4%, Red 63%, Far-Red 13% and infrared 3%, BGR; Blue 20%, Green 23%, Red 47%, Far-Red 8% and infrared 2%; and GR; Blue 25%, Green 41%, Red 32%, and Far-Red 2%) and nitrogen levels (3.6 and 14.3 mM N) on spinach (Spinacea oleracea). Under limited nitrogen (3.6 mM), BGR light increased the fresh shoot (32%) and root (39%) biomass than BR, suggesting additional green light's impact on assimilating photosynthates under suboptimal nitrogen availability. Reduced chlorophyll (a and b) and carotenoid accumulation, electron transport rate (ETR), and higher oxalates under limited nitrogen availability highlighted the adverse effects of red light (BR) on spinach productivity. Increased activities of nitrogen-associated enzymes (GOGAT; Glutamate synthase, GDH; NADH-Glutamate dehydrogenase, NR; Nitrate reductase, and GS; Glutamine synthetase) in spinach plants under BGR light further validated the significance of green light in nitrogen assimilation. Amino acid distributions remained unchanged across the light spectra, although limited nitrogen availability significantly decreased the percent distribution of glutamine and aspartic acid. Overall, this study demonstrated the favorable impacts of additional green light on spinach productivity, as demonstrated under BGR, than GR alone in response to nitrogen perturbation. However, the exact mechanisms underlying these impacts still need to be unveiled. Nevertheless, these outcomes provided new insights into our understanding of light spectra on spinach nitrogen metabolism.

Moringa olifera leaf extract increases physio-biochemical properties, growth and yield of Pisum sativum grown under salinity stress

The soil salinity is a dominant abiotic problem in arid and semi-arid region of the world. It occurs naturally due to low rainfall and accumulation of salts to soil surface, aided by human activities; excessive irrigations, over-use of fertilizers and poor drainage. The study was aimed to investigate the mitigating role of Moringa olifera leaf extract (MLE) in pea grown under salinity stress. Pea (Pisum sativum) variety-Pea-2009 was grown under control and salt (100 mM NaCl) stress. The MLE extract (3%) was applied as a seed priming and foliar spray. Salinity stress caused a significant (P<0.001) decrease in plant growth (fresh and dry biomass of shoot and root s), leaf relative water contents, chlorophyll a and b, carotenoid, TFAAs, proline, K+ and antioxidants (POD, APX, and CAT), whereas the application of MLE either (seed priming/foliar spray) enhanced all studied attributes under both control and saline conditions. However, Na+, MDA, and H2O2 contents were enhanced under salinity stress. Whereas the application of MLE (seed priming/ foliar spray) enhanced shoot and root fresh and dry weights as compared to saline treatment. While on the other hand the application of MLE (seed priming/ foliar spray) enhanced leaf relative water contents, total chlorophyll contents, total soluble proteins, total free amino acids, catalase, peroxidase, ascorbate peroxidase, proline, K+ contents of shoot and root while lowered H2O2, MDA, Na+ contents of root and shoot compared to their respective saline treatments. Similarly, MLE also enhanced pea seed yield to 36% (priming) and 33 (foliar spray) under salinity stress which was reduced to 56% under salinity stress. The exogenous application of MLE either seed priming or foliar spray, potentially enhanced growth and yield of economically important crops grown under salinity stress by maintaining better physio-biochemical indices.

Grafted and Nongrafted ‘Cherokee Purple’ Tomato Performance in Aquaponic and Hydroponic Greenhouse Production in Oklahoma

‘Cherokee Purple’ tomato (Solanum lycopersicum L.) plants are a highly sought-after heirloom cultivar in the United States but are low yielding and highly susceptible to soil-borne pathogens, and may benefit from being grafted. Soilless systems such as aquaponics and hydroponics help increase yield, mitigate disease, and serve as an alternative to field production. The objective of this study was to evaluate a grafting combination of ‘Cherokee Purple’ × ‘Maxifort’ and nongrafted controls in 1.85-m2 media grow beds with hydroponic and aquaponic systems using copper nose bluegill in a greenhouse. Grafting increased stem diameter, leaf count, stem height, flower count, and bud count compared with nongrafted plants. In aquaponics, grafting increased the phosphorus uptake over nongrafted plants grown in the aquaponic system. Grafting resulted in greater fresh (49.2%) and dry (40.0%) shoot biomass, and fresh (33.3%) and dry (42.8%) root biomass. Grafting also increased the uptake of copper and sulfur in the aquaponic systems. The hydroponic systems resulted in greater leaf count, soil plant analysis development, stem height, shoot biomass, and greater boron, phosphorus, potassium, iron, and manganese levels than aquaponic systems. Total fruit number and weight were greater in hydroponic systems than in aquaponic systems by 35.4% and 30.4%, respectively, but fruit splitting was a problem in both. Aquaponics resulted in greater root fresh weight than hydroponics. The nutrients zinc and copper increased with the use of aquaponic systems over hydroponic systems. This research suggests that the type of system can affect growth and nutrient uptake, and ‘Cherokee Purple’ should not be used in a soilless system because of excessive fruit splitting, leading to unmarketable fruit and low yield, unless environmental conditions can be managed during the heat of the summer.

Exploring the impact of salinity on citrus (Citrus spp.) rootstock seed germination and seedling biomass

An experiment was conducted at the screen house of the Department of Horticulture, CCS Haryana Agricultural University, Hisar, Haryana during 2018–19 and 2019–20 to assess the impact of 5 different salinity levels [0.07 (control), 2.5, 4.0, 5.5, and 7.0 dS/m] on the seed germination and biomass of 9 citrus (Citrus spp.) rootstock seedlings (Rough lemon, Pectinifera, Cleopatra mandarin, Rangpur lime, Alemow, Volkamer lemon, NRCC-4, NRCC-3 and CRH-12). Experiment consisted of 45 treatment combinations and 3 replications in a completely randomized design (CRD). Under the influence of soil salinity, the number of days taken for seed germination, seed germination percentage, fresh and dry root and shoot biomass were adversely affected across all rootstocks compared to the control treatment (0.07 dS/m). Among the tested rootstocks, Volkamer lemon exhibited the highest seed germination rate (57%), followed by Rangpur lime (53%) and CRH-12 (50%). Conversely, Pectinifera showed the lowest seed germination percentage (37%), followed by Alemow (43%) at 7 dS/m. The minimum reduction at 7 dS/m over control in fresh shoot and root and dry shoot and root biomass was observed in Rangpur lime (37.7, 16.2, 27.8 and 27.3%, respectively), followed by Volkamer lemon (38.0, 16.2, 28.3 and 28.5%, respectively). On the other hand, Pectinifera exhibited the highest reduction in biomass (51.9, 40.5, 47.0 and 43.9%, respectively), followed by Alemow (45.7, 30.9, 46.5 and 39.9%, respectively). Among all the rootstocks, Rangpur lime, Volkamer lemon and Cleopatra mandarin displayed better tolerance to salinity, exhibiting relatively lower reduction in biomass at the highest salinity level (7 dS/m) compared to the control. Cleopatra mandarin, Rough lemon and NRCC-3 showed a moderate response, while Pectinifera, NRCC-4, and Alemow were found to be less tolerant, exhibiting higher reduction in terms of count of seed germination days, seed germination percentage, fresh and dry root biomass, and shoot biomass at 7 dS/m compared to the control treatment.

MERCI: a simple method and decision-support tool to estimate availability of nitrogen from a wide range of cover crops to the next cash crop

Background and aimsCover crops can efficiently increase nitrogen (N) recycling in agroecosystems. By providing a green-manure effect for the next crop, they allow reduced mineral fertilisation. We developed a decision-support tool, called MERCI, to predict N available from cover crop residues over time, from a single measurement of fresh shoot biomass.MethodsWe coupled a large experimental database from France with a simulation experiment using the soil-crop model STICS. More than 25 000 measurements of 74 species of cover crops as a sole crop or bispecific mixtures were collected. Linear regression models, at the species, family or entire-database level depending on the data available, were built to predict dry biomass, N amount and C:N ratio. Dynamics of N mineralized and leaching from cover crop residues were predicted at 24 contrasting sites as a function of the biomass, carbon (C):N ratio and termination date.ResultsCorrelations between fresh biomass, dry biomass and N amounts in experimental data were strong (r = 0.80-0.96), and predicted N amounts in fresh shoot biomass were relatively accurate. Percentages of N mineralized and leached simulated by STICS were explained mainly by the C:N ratio, site and number of months after termination, but to different degrees.ConclusionMERCI is an easy and robust decision-support tool for predicting N release in the field, and could thus be adopted by advisors and farmers to improve management of nutrient recycling in temperate arable cropping systems.

Screening For Salt Tolerance of 12 Turkish Triticale Cultivars during Germination and Early Seedling Stage

This investigation was carried out to determine the response of 12 Turkish cultivars to different salt stress levels during the germination and early seedling stages at Hatay Mustafa Kemal University in 2022. In present research, four different sodium chloride treatments (60, 120, 180 and 240 mM) and a control (0 mM) treatment were used. Germination ratio, germination index, mean germination time, root and shoot length, root and shoot fresh weight, root and shoot dry weight and biomass weight parameters were investigated to determine the salt tolerance of triticale cultivars. Cultivars, salt doses and their interactions had significant effects on all examined characteristics. In general, germination parameters and early seedling stage characteristics of the cultivars were adversely affected by increasing salt doses. Yet, it was determined that the responses to increasing salt doses were different among the cultivars. Although Mehmetbey cultivar was undesirably affected by increased salt doses, it was found to be more resistant than the other cultivars. On the other hand, Umranhanim was determined as the most sensitive cultivar to salt stress. After investigating the resistance of Mehmetbey cultivar to salt stress under field conditions, this cultivar can be included into breeding programs or cultivated in fields with salinity problems.

Key factors influencing arsenic phytotoxicity thresholds in south China acidic soils

Arsenic (As) toxicity threshold values (TTVs) for plants are fundamental to both establishing regional As reference values in soil and performing risk assessment. However, TTVs vary with plant species and soil types. In this study, a hydroponic experiment with 16 plant species was conducted to screen the most As-sensitive plant species. The results showed that the EC20 (available As concentration at which shoot biomass or height is inhibited by 20%) values were 1.38–104.4 mg L−1 for shoot height and 0.24–42.87 mg L−1 for shoot fresh biomass. Rice was more sensitive to As toxicity than the other species. Therefore, it was chosen as the ecological receptor in the pot experiment on As phytotoxicity in nine types of soils collected from Fujian Province in South China. The EC10 and EC20 with respect to rice shoot height were 3.72–29.11 mg kg−1 and 7.12–45.60 mg kg−1, respectively. Stepwise regression analysis indicated that free iron oxide concentration is the major factor that affects As bioavailability in soil, and ECx (x = 10, 20, and 50) of soil available As for shoot height was positively related to free iron oxide concentration in soil. In addition, soil cation exchange capacity, clay (<0.002 mm) content, and exchangeable magnesium content are also important factors influencing As phytotoxicity in acidic soils. The regression models can be used to predict As phytotoxicity in acidic soils.

Influence of a plant growth booster on the growth and quality parameters of Juniperus polycarpos seedlings under nursery conditions

ABSTRACT An experimental trial was conducted to study the influence of a plant growth booster (PGB) on the seedling growth and quality parameters of Juniperus polycarpos in nursery conditions. One-year-old seedlings were applied with seven different doses of a PGB composed of humic acid (12%), fulvic acid (4.3%), seaweed extract (6.9%), and amino-based granules (6.8%) to study their effect on seedling growth and quality parameters. After 5 years in the nursery, maximum values of seedling growth parameters viz. shoot length (43.10 cm), root length (42.00 cm), collar diameter (5.93 mm), number of roots (41.00), fresh shoot biomass (18.83 g), fresh root biomass (5.87 g), total fresh biomass (24.71 g), dry shoot biomass (10.11 g), dry root biomass (3.06 g), and total dry biomass (13.17 g) were recorded in seedlings that were given 2.5 g PGB/seedling, as compared to the seedlings where no PGB was applied. The maximum value of quality parameters viz. volume index (1515.60) and quality index (1.25) was also observed in seedlings that received 2.5 g PGB/seedling. The study suggests the application of 2.5 g PGB per seedling for the production of quality planting stock of J. polycarpos in the nursery.

Aloe Vera Extract Gel-Biosynthesized Selenium Nanoparticles Enhance Disease Resistance in Lettuce by Modulating the Metabolite Profile and Bacterial Endophytes Composition.

The use of nanotechnology to suppress crop diseases has attracted significant attention in agriculture. The present study investigated the antifungal mechanism by which aloe vera extract gel-biosynthesized (AVGE) selenium nanoparticles (Se NPs) suppressed Fusarium-induced wilt disease in lettuce (Lactuca sativa). AVGE Se NPs were synthesized by utilizing sodium selenite as a Se source and AVGE as a biocompatible capping and reducing agent. Over 21 d, 2.75% of total AVGE Se NPs was dissolved into Se ions, which was more than 8-fold greater than that of bare Se NPs (0.34%). Upon exposure to soil applied AVGE Se NPs at 50 mg/kg, fresh shoot biomass was significantly increased by 61.6 and 27.8% over the infected control and bare Se NPs, respectively. As compared to the infected control, the shoot levels of citrate, isocitrate, succinate, malate, and 2-oxo-glutarate were significantly upregulated by 0.5-3-fold as affected by both Se NPs. In addition, AVGE Se NPs significantly increased the shoot level of khelmarin D, a type of coumarin, by 4.40- and 0.71-fold over infected controls and bare Se NPs, respectively. Additionally, AVGE Se NPs showed greater upregulation of jasmonic acid and downregulation of abscisic acid content relative to bare Se NPs in diseased shoots. Moreover, the diversity of bacterial endophytes was significantly increased by AVGE Se NPs, with the values of Shannon index 40.2 and 9.16% greater over the infected control and bare Se NPs. Collectively, these findings highlight the significant potential of AVGE Se NPs as an effective and biocompatible strategy for nanoenabled sustainable crop protection.

Flooding period influence early growth of Grevillea robusta nursery seedlings

Flooding has become a common occurrence due to climate change leading to prolonged water-logging which suffocates plant rooting, thus reduced growth, yield or total loss. Limited research has been conducted on the same. This study is aimed at investigating the effect of flooding period on the early growth of Grevillea robusta nursery seedlings in Njoro, Kenya. An experiment was set up for 2 months in Egerton University Agroforestry tree nursery using a six months old Grevillea seedlings. Completely randomized block design (RCBD) with 4 treatments replicated 3 times was used. The treatments were: Non-flooding, 2 days flooding, 4 days flooding and 6 days flooding. Data was collected for shoot, foliage and root variables and analyzed using SAS statistical package while means were separated using least significance difference (LSD). Non-flooding recorded the highest performance for all the shoot and foliage variables while the least was 2 days flooding. On the other hand, 6 days flooding was the second in performance for most of the variables especially 3rd internode length (20.2 mm) and fresh shoot biomass (56.4 g) were significantly (P=0.002 and 0.05) higher respectively compared with 2 days flooding (13.5 mm and 46.7 g) respectively. In conclusion, flooding affects the growth of Grevillea seedlings negatively by reducing their growth and this was more pronounced in 2 days flooding. However, for 6 days flooding, the seedlings seem to adjust through development of adaptive strategies in the roots. Further research needs to be conducted on other species and also prolonged flooding period.

Effects of potassium fertilizer rates on growth, tuber yield and quality of sweet potato (Ipomea batatas L) in Ogbomoso, Southwest Nigeria

Sweet potato (Ipomoea batatas L) is an important dicotyledonous tuberous staple crop of the Convolvulaceae family. It is valued for its tubers which are either boiled, fried, baked or roasted for human consumption or boiled and fed to livestock as a source of energy. However, the cultivation of sweet potato is constrained by low soil fertility, particularly inadequate potassium, which plays a pivotal role in the growth and tuber development of sweet potato. Therefore, the effects of potassium fertilizer rates on the growth, tuber yield and quality of sweet potato were determined at the Teaching and Research Farm, Ladoke Akintola University of Technology, Ogbomoso during 2022 major cropping season. The treatments were; 0 (control), 60, 90, 120, 150 and 180 kg K2O/ha laid out in randomized complete block design replicated three times. Data collected on length of primary vines, number of leaves, fresh shoot biomass, number of tubers, fresh tuber yield and nutritional contents of the tubers were subjected to analysis of variance and treatment means separated with least significance difference (LSD) at 5% probability level. The application of K fertilizer had significant influence on the performance of sweet potato. At 14 weeks after planting (WAP), plants treated with 180 kg K2O/ha produced the longest mean vine length (p = 0.043, 184.93 cm), highest number of leaves (p = 0.003, 217), highest fresh shoot biomass (p = 0.015, 11.83 t/ha), number of tubers (p = 0.037, 68) and fresh tuber yield (p = 0.0004, 22 t/ha). In contrast, plants that received no fertilizer, had the shortest vine length (133.67 cm), the least fresh shoot biomass (7.1 t/ha) and tuber yield (12.7 t/ha). The least number of leaves (136) was observed with the application of 60 kg K2O/ha while 90 kg K2O/ha produced the least number of tubers (46). The potassium content of sweet potato tuber was significantly influenced by K fertilizer rates, whereas the phosphorus content was unaffected. The highest contents of phosphorus (p = 0.967, 0.10%) and potassium (p = 0.038, 1.26%) were recorded in tubers that received 150 kg K2O/ha and 180 kg K2O/ha, respectively. The carotenoid, carbohydrate, and protein contents of sweet potato tuber decreased as the potassium rates increased. Conversely, the crude fiber content increased (p = 0.044) as the potassium rate increased. In conclusion, application of 180 kg K2O/ha improved the performance of sweet potato better than the other rates in the study area. However, it seems that the maximum yield potential of sweet potato in the study area had not been attained. Therefore, further research with higher than 180 kg K2O/ha may be required to identify the optimal level for cultivating sweet potatoes.

COMPARATIVE STUDY OF ROOTSTOCKS AND THEIR EFFECTS ON STIONIC ESTABLISHMENT OF THE MANGO SEEDLINGS

To explore the quality rootstock which impart better stionic establishment of the mango seedlings, we studied the comparative effect of scion and rootstock using three mango scion varieties (Sindhri, Chaunsa and Neelum) grafted on three rootstocks i.e. Ratam, Pado and Sindhri. Parameters including seed germination (%), seedling height (cm), leaves seedling rootstock-1, seedling vigor index (SVI), fresh biomass of shoot and roots (g), dry biomass of shoot and roots (g), chlorophyll content (rg), rootstock diameter (mm), scion diameter (mm), stionic ratio, leaves graft-1 and sturdiness quotient were studied. Results showed the best seed germination (88.33%), seedling vigor index (5158.74), and sturdiness quotient (3.89) in Pado rootstock. However maximum fresh biomass of shoot (20.67 g), fresh biomass of roots (16.2 g), dry biomass of shoot (12.65 g), dry biomass of roots (8.33 g) and scion diameter of the rootstocks were observed in Sindhri rootstocks. Regarding grafting data, the best stionic ratio (0.93) was observed from the scion and rootstock combination of Neelum and Pado rootstock. It was concluded that Pado rootstock performed better in terms of seedling rootstock and for successful stionic establishment of the mango seedlings

Environmental factors and non-chemical methods to suppress growth of the invasive plant Gutenbergia cordifolia

Little is known about preferred environmental conditions and non-chemical control of invasive Gutenbergia cordifolia. We assessed the effects of different A. annua crude extract concentrations, synthetic herbicide (glyphosate), fire regime and shade to G. cordifolia germination, shoot and root dry biomass, seedling height and leaf chlorophyll. High concentrations (75%) of A. annua crude extracts significantly reduced germination percentage of G. cordifolia by 25% (F2,4=77.2, p < 0.001), and suppressed shoot and root dry biomass (F2,4 = 80.3, p < 0.001; F2,4=46.104, p < 0.001, respectively) as well as seedling height and leaf chlorophyll (F2,4 = 12.02, p < 0.002; F2,4 = 15.9, p < 0.001), respectively. Medium temperature (60 °C) and long exposure time (5 min) significantly increased G. cordifolia germination percentage (F2,7 = 32.6, p < 0.001) while extreme temperatures (≥150 °C) at both (1 min) short and (5 min) long exposure time completely suppressed germination of G. cordifolia. Under high shade, while germination percentage was a third that of other treatments (F2, 4 = 20.9, p = 0.008), mean germination took twice as long (F2, 4 = 17.9, p = 0.010) and shoot fresh biomass was reduced by half (F 2, 4 = 16.92, p = 0.004). Shoot and root dry biomass were reduced to more than a third under high shade, seedling height reduced to half but leaf chlorophyll content was not affected (F 2,4 = 6.3, p = 0.030; F 2,4 = 9.1, p = 0.020; F 2,4 = 18.3, p = 0.003; F 2,4 = 3.02, p = 0.120, respectively). We suggest using A. annua as a potential bio-herbicide and highlight considering fire and shade as suppressor tools to control G. cordifolia, but first include in-situ trials to assess their impacts to both native plants and animals.

Mycorrhizae Enhance Soybean Plant Growth and Aluminum Stress Tolerance by Shaping the Microbiome Assembly in an Acidic Soil.

Strongly acidic soils are characterized by high aluminum (Al) toxicity and low phosphorus (P) availability, which suppress legume plant growth and nodule development. Arbuscular mycorrhizal fungi (AMF) stimulate rhizobia and enhance plant P uptake. However, it is unclear how this symbiotic soybean-AMF-rhizobial trio promotes soybean growth in acidic soils. We examined the effects of AMF and rhizobium addition on the growth of two soybean genotypes, namely, Al-tolerant and Al-sensitive soybeans as well as their associated bacterial and fungal communities in an acidic soil. With and without rhizobial addition, AMF significantly increased the fresh shoot and root biomass of Al-tolerant soybean by 47%/87% and 37%/24%, respectively. This increase in plant biomass corresponded to the enrichment of four plant growth-promoting rhizobacteria (PGPR) in the rhizospheric soil, namely, Chitinophagaceae bacterium 4GSH07, Paraburkholderia soli, Sinomonas atrocyanea, and Aquincola tertiaricarbonis. For Al-sensitive soybean, AMF addition increased the fresh shoot and root biomass by 112%/64% and 30%/217%, respectively, with/without rhizobial addition. Interestingly, this significant increase coincided with a decrease in the pathogenic fungus Nigrospora oryzae as well as an increase in S. atrocyanea, A. tertiaricarbonis, and Talaromyces verruculosus (a P-solubilizing fungus) in the rhizospheric soil. Lastly, the compartment niche along the soil-plant continuum shaped microbiome assembly, with pathogenic/saprotrophic microbes accumulating in the rhizospheric soil and PGPR related to nitrogen fixation or stress resistance (e.g., Rhizobium leguminosarum and Sphingomonas azotifigens) accumulating in the endospheric layer. IMPORTANCE Taken together, this study examined the effects of arbuscular mycorrhizal fungi (AMF) and rhizobial combinations on the growth of Al-tolerant and Al-sensitive soybeans as well as their associated microbial communities in acidic soils and concluded that AMF enhances soybean growth and Al stress tolerance by recruiting PGPR and altering the root-associated microbiome assembly in a host-dependent manner. In the future, these findings will help us better understand the impacts of AMF on rhizosphere microbiome assembly and will contribute to the development of soybean breeding techniques for the comprehensive use of PGPR in sustainable agriculture.

Nanomaterial Size and Surface Modification Mediate Disease Resistance Activation in Cucumber (Cucumis sativus).

Crop disease represents a serious and increasing threat to global food security. Lanthanum oxide nanomaterials (La2O3 NMs) with different sizes (10 and 20 nm) and surface modifications (citrate, polyvinylpyrrolidone [PVP], and poly(ethylene glycol)) were investigated for their control of the fungal pathogen Fusarium oxysporum (Schl.) f. sp cucumerinum Owen on six-week-old cucumber (Cucumis sativus) in soil. Seed treatment and foliar application of the La2O3 NMs at 20-200 mg/kg (mg/L) significantly suppressed cucumber wilt (decreased by 12.50-52.11%), although the disease control efficacy was concentration-, size-, and surface modification-dependent. The best pathogen control was achieved by foliar application of 200 mg/L PVP-coated La2O3 NMs (10 nm); disease severity was decreased by 67.6%, and fresh shoot biomass was increased by 49.9% as compared with pathogen-infected control. Importantly, disease control efficacy was 1.97- and 3.61-fold greater than that of La2O3 bulk particles and a commercial fungicide (Hymexazol), respectively. Additionally, La2O3 NMs application enhanced cucumber yield by 350-461%, increased fruit total amino acids by 295-344%, and improved fruit vitamin content by 65-169% as compared with infected controls. Transcriptomic and metabolomic analyses revealed that La2O3 NMs: (1) interacted with calmodulin, subsequently activating salicylic acid-dependent systemic acquired resistance; (2) increased the activity and expression of antioxidant and related genes, thereby alleviating pathogen-induced oxidative stress; and (3) directly inhibited in vivo pathogen growth. The findings highlight the significant potential of La2O3 NMs for suppressing plant disease in sustainable agriculture.

COMPARATIVE EFFECT OF SEED PRIMING AND GROWING MEDIA ON SEED GERMINATION AND SEEDLING GROWTH OF PAPAYA (CARICA PAPAYA L.)

An experiment was directed to assess the comparative effect of seed priming and growing media on seed germination and growth of papaya. Papaya seeds were primed in distilled water, 1% potassium nitrate (KNO3) for 12 hours. The un-primed seeds were taken as control. The growing medium was prepared by mixing different ratios of the canal silt, bagasse, and cocopeat. Results have shown that each experimental parameters in the current investigation was influenced by seed priming and growing media. Moreover the findings revealed that, seed priming with distilled water got the highest mean seed germination, seedling vigor index, fresh biomass of shoot and root, dry biomass of shoot, dry root weight, quality index of the seedlings, sturdiness quotient, survival % and mean germination time. While to compare means of the growing media, M2 (Canal silt + bagasse + cocopeat in 1:1:1) medium had the best results for seed germination, seedling vigor index, fresh biomass of shoot and root, dry biomass of shoot and root, quality index of the seedlings, sturdiness quotient, lowest mean germination time and leakage of the electrolytes. It’s determined from the current study that seed priming with distilled water and M2 medium contained canal silt, bagasse and cocopeat in (1:1:1) found optimal for all germination and seedling attributes of papaya.

Influence of pot size on early seedling growth of Grevillea robusta and Cupressus lusitanica in Kenya

Pot size is vital for raising of nursery seedlings. Different sizes of pots are needed for various tree species. An experiment was set up to investigate the best pot size for Cupressus lusitanica and Grevillea robusta species. The experiment was laid down as a RCBD with 8 treatments replicated 3 times. Treatments comprised of 4 different pot sizes as follows: large, medium, small and smallest as well as two species. Forest soil mixture was used for potting and 10 pots were used per each treatment per replicate while 7 plants were randomly selected for sampling. The experiment was carried out from September 2017 for a period of 8 months. The variables measured included; shoot, foliage and roots. ANOVA was done using Genstat package while the means were separated at P&lt; 0.001 using LSD. The results showed that large pots had significantly (P&lt;0.001) higher values in height, shoot fresh biomass, total fresh plant biomass and seedling stem volume compared with the other pot sizes. Large pots also showed significantly higher root collar diameter (6.23 mm) compared with the medium pot (4.33 mm). For species, Cypress showed significantly superior height (27.84 cm) and number of leaves (24.52) compared with Grevillea (18.73 and 18.27 cm respectively). In conclusion, shoot fresh biomass and total fresh plant biomass were positively correlated with pot size. This study recommends the use of large pots for raising Grevillea and Cypress seedlings in the nursery since they take 8 months to attain planting size.

Response of germination and seedling growth of Jute plant (Corchorus olitorius L.) on three different substrates in the tilapia aquaponic system

The merging of fish farming and crop husbandry in a mutual system forms aquaponics. In this system, the nature of the planting substrate plays a significant role in the germination, establishment, and growth of the plant. In the current experiment, the germination and growth of the Jute plant ( Corchorus olitorius L . ) in an aquaponics system with tilapia fish was investigated using three different substrate types: gravel, rice husk, and palm kernel shell. Five hundred-liter plastic tanks containing tilapia fingerlings at initial stocking densities of 250 fish m −3 were used. One gram of Jute seed was sown in a 1 m 2 planting trough, which contained the three substrates separately in triplicates. The troughs were flooded with water from fish holdings by an aquarium pump. The germination percentage of the jute plant on gravel substrate (84%) and rice husk (72%) was significantly higher (P < 0.05) compared to the palm kernel shell (55%). A lower velocity of germination was also recorded in the palm kernel substrate. The rates of growth in height (centimeters per day) of jute plant and fresh shoot biomass yield were significantly lower on palm kernel substrate (P < 0.05). Growth and yield parameters of jute showed comparatively higher agronomic efficiency of gravel and rice husk substrates compared to palm kernel substrates in this research. The results indicated that substrate nature significantly affects the germination and productivity of C. olitorius in aquaponic systems and that rice husk has the potential to serve as a planting substrate in aquaponics. • Response of germination and seedling growth of Jute plant ( Corchorus olitorius L.) on three different substrates in the tilapia aquaponic system. • Influence of substrate types on the germination and productivity of C. olitorius in aquaponic systems. • Potentials of rice husks as planting substrate for Jute in the aquaponic system.

Efficacy of novel water‐absorbing polymer amended soil for improving drought resilience of Solanum lycopersicum

AbstractClimate change has exacerbated the frequency and duration of droughts. To sustain food production in such conditions, water storage and retention capacity of soil must be enhanced. Development of water‐absorbing polymer (WAP) from coal carbon residue (fly ash) can provide an economical and environmentally friendly alternative to commercial WAP for enhancing water retention and crop yield. The main objective of this study is to evaluate the growth performance of tomato species (Solanum lycopersicum L.) under continued drought conditions in the presence of in‐house developed fly ash‐based WAP (FA‐WAP) against that of commercially available WAP (Com‐WAP). Quantification of the soil–water retention curve (SWRC) revealed an increase in plant wilting time and plant‐available water content (PAWC) in the order: control soil (no amendment) &lt; Com‐WAP‐amended soil &lt; FA‐WAP‐amended soil. Both the WAPs positively influenced the transpiration factors of crops in terms of stomatal conductance (SC) and photosynthetic yield under continued drought conditions. The yield parameters (i.e., the number of fruits, total weight, and shoot fresh biomass) increased by 82, 106, and 115%, respectively, in the case of FA‐WAP‐amended soil as compared with that of the control. Nevertheless, FA‐WAP provided 20% higher yield of tomato species during continued drought conditions than commercial WAP. The application of FA‐WAP can be an effective strategy to impart beneficial usage of FA waste by significantly reducing the irrigation frequency and irrigation water requirement without compromising the crop yield. It also ensures sustainable water stress management for a major food crop (tomato), thereby contributing towards United Nation's Sustainable Development Goals 2, 13, and 15.

Flavonoids and Devosia sp SL43 cell-free supernatant increase early plant growth under salt stress and optimal growth conditions.

Salt stress is a major threat to modern agriculture, significantly affecting plant growth and yield, and causing substantial economic losses. At this crucial time of increasing climate change conditions, soil salinity will continue to develop and become an even more serious challenge to crop agriculture. Hence, there is a pressing need for sustainable techniques in agricultural production that could meet the dual challenges of crop productivity and environmental instability. The use of biostimulants in agricultural production has greatly influenced plant health and global food production. In particular, the application of bioactive materials produced by beneficial microbes is becoming a common practice in agriculture and provides numerous benefits to plant growth and resistance to stressful conditions. In this research two biostimulants; a type of plant secondary metabolite (flavonoids) and a microbe-based material (CFS: Cell-Free Supernatant) containing active compounds secreted by a novel bacterial strain isolated from Amphecarpaea bracteata root nodules (Devosia sp - SL43), have been utilized to improve the growth and stress resistance of two major oil seed crops; canola and soybean, under optimal and salt stress conditions. Our findings suggested significant improvements in crop growth of canola and soybean following the application of both biostimulants. Under optimal growth conditions, soybean growth was significantly affected by foliar spray of flavonoids with increases in shoot fresh and dry weight, and leaf area, by 91, 99.5, and 73%, respectively. However, soybean growth was unaffected by flavonoids under salt stress. In contrast, CFS with a meaningful capacity to mitigate the negative effects of salinity stress improved soybean shoot fresh biomass, dry biomass, and leaf area by 128, 163 and 194%, respectively, under salt stress conditions. Canola was less responsive to both biostimulants, except for canola root variables which were substantially improved by flavonoid spray. Since this was the first assessment of these materials as foliar sprays, we strongly encourage further experimentation to confirm the findings reported here and to determine the full range of applicability of each of these potential technologies.