Leaves Research Articles

Influence of plant growth regulators on morphological and flowering behavior of bottle gourd (Lagenaria siceraria (Mol.) Standl.)

A field experiment was conducted for evaluating the influence of three plant growth regulators (PGR) viz., gibberellic acid (GA3), Naphthalene acetic acid (NAA) and Ethrel on morphological and flowering behaviour of bottle gourd. The foliar application of Ethrel @ 300 ppm was found beneficial for days taken for appearance of first female flower, number of male flowers, number of female flowers, sex ratio. Whereas, maximum length of vine at 60 and 90 DAS, minimum number of days taken from fruit set to edible maturity was obtained by the foliage application of GA3 @ 40 ppm however minimum days taken for appearance of first male flower was obtained with GA3 @ 60 ppm. Based on these observations, it could be suggested that the significant increase in flowering and growth characters would be obtained by the spraying of Ethrel @ 300 ppm at 2-4 true leaf stage.

Possibilities of weed control of Chenopodium album and other weeds in sugar beet crop after possible non-approval of lenacil

The field research were carried out in 2021–2022, in Mariza sugar beet cultivar. The aim of the study was to develop an alternative weed control program without lenacil. The tested mixtures containing metamitron, ethofumesate, triflusulfuron-methyl, clopyralid, dimetha­namid-P and quinomerac, used in various combinations together with the Atpolan BIO 80 EC Premium adjuvant, effectively controlled Chenopodium album up to phase 1 of the true leaf pair (BBCH 11). The absence of ethofumesate in the composition of mixtures or the use of metamitron (1050 g/ha) with triflusulfuron-methyl (15 g/ha) results in a deterioration in the effectiveness of combating Ch. album indencisive results. The addition of dimethanamide-P and quinomerac to the mixture of metamitron, ethofumesate and clopyralid gave inconclusive results. Depending on the year of the study, comparable control efficiency was obtained, oscillating in the range of the mixture of metamitron with ethofumesate, or a negligible improvement. The conducted research proved that the withdrawal of lenacil affect the deterioration of the effectiveness of combating Ch. album.

Exogenous Application of Ascorbic Acid to Induce Tolerance Against Salt Stress in Common Bean Plants

Common beans have an important place in the world due to its high nutritional values in the human diet and with the largest cropping area among the legumes. Besides, they are named as quite sensitive to salt stress. Salinity is one of the utmost abiotic stress factors limiting agricultural production, which affects plant growth and development at different levels. Lately, exogenous applications of signalling and/or protective molecules to various parts of plants are used to combat salt stress before or at the time of stress. In this context, this research was conducted to assess the influence of foliar-applied ascorbic acid (AsA) on electrolyte leakage (EL), activity of antioxidative enzymes, total protein (TSP) content and protein profiles in the two common bean genotypes (salt-sensitive “Local Genotype” and salt-tolerant “Şeker Fasulye”) at early growth stage under salinity (0, 50, 100, 150 mM NaCl). The genotypes were exposed to salt stress from fully developed true leaf at the third nodes emerged stage for two weeks, meanwhile 3 mM AsA was foliar-applied every three days. Salt stress increased EL in both genotypes and exogenous AsA application decreased EL value especially in “Local Genotype”. Foliar-applied AsA generally reduced the adverse effects of NaCl on AsA content of both genotypes. Exogenous AsA application also increased the activities of catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) in the salt-stressed common bean plants and did not play a role in the TSP content. However, it has been determined that SDS-PAGE protein profiles represent adaptive mechanisms for dealing with excess salt in common bean genotypes. The results suggested that foliar-applied AsA was effective in reducing the adverse effects of salinity especially in relatively salt sensitive common bean genotype.

NFLUENCE OF GREENHOUSE MAINTENACE TREATMENTS ON GROWTH OF SEEDLING GRAPEVINES (Vitis spp.)

Vegetative clonal propagation of scions and rootstocks represent the commercial method of grapevine production; currently, techniques such as hardwood rooting, grafting, and tissue culture are readily exploited by the nursery and grapevine industries. Seedlings of highly heterozygous grapevines are not true to type, as a result they are not utilized in the mass production of planting stock for commercial grape vineyards. However, seedling growth and quality is key for plant breeding programs initiating thousands of unique seedlings each year. To investigate treatments for their impact on diverse interspecific cold-hardy grapevines, seedlings were grown under greenhouse conditions. Four weeks after transplant, seedlings were cut back to one true node (CUT), leaf thinned (LT), or left as untreated control vines (Control). Eight weeks after treatment, plants were analyzed for total node number, periderm encompassed nodes, lateral shoot number, and total number of base stems. Control and LT vines had more periderm encompassed nodes and total nodes than CUT vines, while CUT vines had the highest number of shoots arising from the base nodes of the vine.

Response of cucumber (Cucumis sativus L. Cv. Bhaktapur local) to the application of plant growth regulators in plastic tunnel

The field experiment was conducted to know the yield performance of cucumber var. Bhaktapur Local with the application of plant growth regulators (PGRs) in the farmers’ field of Lamjung, Nepal during September to November, 2013. Five treatments (Four PGRs; NAA @10 ppm, GA3 @ 50ppm, GA3 @100ppm, MH@ 60ppm and distilled water as control) were replicated six times under walk-in plastic tunnel. The experiment was laid out in randomized complete block design. The first 30 flowers of each plant were used for the observation. PGRs were sprayed in 2-4 true leaf stage of seedling, 20 days after first spray and 10 days after second spray. The research revealed that NAA @ 10 ppm had higher effect in sex expression, fruit set and yield than rest of the treatments. GA3 @ 100 ppm had significantly higher number of male flowers and more vine growth than other treatments. Branch per plant was obtained as the highest with MH @60 ppm followed by NAA @10 ppm. The marketable fruit yield was significant with NAA @10 ppm followed by MH@ 60 ppm, GA3 @50 ppm, GA3 @100 ppm than control. It is concluded that thermo-sensitive variety of cucumber Bhaktapur Local can be grown with the use of plant growth regulators particularly, NAA@ 10 ppm, under walk-in plastic tunnels during the autumn-winter season in the mid hills of Nepal. The research further indicated that cucumber can be a profitable and a potential agriculture enterprise for the area.

Clonostachys rosea Strain ST1140: An Endophytic Plant-Growth-Promoting Fungus, and Its Potential Use in Seedbeds with Wheat-Grain Substrate

In this study, Clonostachys rosea strain ST1140, a naturally occurring endophyte in healthy roots of a pistachio tree, was identified morphologically and molecularly through DNA sequencing, and its endophytic ability and growth effect in/on three solanaceous plant species were tested. Three different organic substrates (bread wheat-grain, sawdust, and leonardite) were also investigated for their utility in cultivating and multiplying the strain. In-tray and pot experiments, the rates of seed germination and vegetative development of pepper, tomato, and eggplant inoculated with C. rosea at planting were compared to those of non-inoculated controls. In pot experiments, inoculating seedbeds with increasing doses of C. rosea strain ST1140 with wheat-grain substrate resulted in higher plant height values for all plant species, and the strain endophytically colonized the roots of all plant species. In-tray experiments revealed that ST1140 inoculation resulted in 2-4days earlier and 10% higher germination rates for all plant species, as well as more vigorous and accelerated seedling growth (10-13days earlier for seedlings at the 4-5 true leaf stage) on all inoculated plant species. Among three different organic substrates, wheat-grain was found to be the most effective for long-term cultivation and multiplication of the fungus, which could be of interest for its development as a commercial product. These results promised the strain ST1140's use as a biofertilizer in seedbeds with a wheat-grain substrate.

Effects of Some Plant Growth Regulators on Quality of Potted Sunflower

This study was carried out to evaluate the effects of different plant growth regulators on the ornamental sunflower plant. The seedlings belonging to Helianthus annuus L. cv. Sunsantion F1 were planted in plastic pots (2 L) containing peat:perlite (1:1, v/v) medium at four true leaf stage. Spray treatments of aminoethoxyvinil glycine (AVG; 250 and 500 ppm), promalin (5 and 10 ppm), thidiazuron (TDZ; 5-10 µM), ethephon (100 ppm) were applied to seedlings 20 days after transfering to the pots, and treatments were repeated 10 days after the first application. Flower life (days), flower diameter (cm), stem diameter (cm) and plant height (cm) were determined. According to statistical analysis, AVG at 250 ppm significantly increased the flower life from 9.17 d in control plants to 11.08 d whereas there were no significant effects on flower diameter and plant height. Both concentrations of Promalin and TDZ increased stem diameter significantly. However, TDZ increased the flower life from 9.17 d (control plants) to 10.36 at 10 µM and 10.33 at 5 µM TDZ. Ethephon application prevented flower bud opening and caused the leaves to be yellowing. These results may suggest AVG and TDZ pre-treatments increase the quality and shelf-life of the potted sunflower plant.

Development of morphological marker on natural interspecific hybrid seedling of Acacia (Acacia mangium × Acacia auriculiformis) verified by molecular marker

Development of the hybridization between two different species of Acacia mangium and Acacia auriculiformis in Indonesia started in 2009 by establishing an open-pollinated orchard to produce the natural Acacia hybrid seed in Wonogiri District, Central Java Province. The design of the orchard was an alternate row between A. mangium and A. auriculiformis with a spacing of 5 × 5 meters. The orchard produced putative Acacia hybrid seeds firstly in 2013. Based on flowering synchronization between the two species, seeds from 38 sample trees of A. mangium were taken to identify their character seedling morphology to obtain the Acacia putative hybrid. The seedling morphological characteristics observed were leaf development patterns from the emergence of a true leaf (pinnate) until the pseudo leaf (phyllode) emerged. Acacia putative hybrid was then verified using a Simple Sequence Repeat (SSR) marker and Sequence Characterized Amplified Region (SCAR) to obtain the hybrid of A. mangium × A. auriculiformis. The result showed that the presence of 4-pinnate on the seedling development pattern was verified as 100% pure species of A. mangium and the opposite was 100% hybrid. In comparison, the presence of a true leaf of phyllode + 4-pinnate was verified as a 40% hybrid. The final estimation of Acacia hybrid seed production at the hybrid seed orchard on the first flowering was about 3.1% approximately based on the seedling leaf development pattern.

Early Season Growth Responses of Resistant and Susceptible Cotton Genotypes to Reniform Nematode and Soil Potassium Application

A greenhouse study was conducted to investigate the roles that host plant resistance and soil potassium (K) levels play in affecting Rotylenchulus reniformis Linford and Oliveira (Tylenchida: Hoplolaimidae) (RN) populations and early season cotton (Gossypium hirsutum L.) growth. Two upland, RN-resistant cotton lines (G. barbadense introgressions: 08SS110-NE06.OP and 08SS100), a genetic standard (Deltapine 16) and a commercially available susceptible cultivar (PHY 490 W3FE) were evaluated at four different levels of K [100% of recommended rate, 150% of recommended, 50% of recommended, and a base level] from seeding until harvesting, 60 days after sowing (DAS). Quadratic functions (r2 = 0.82 to 0.95) best described the early season growth response of cotton genotypes to soil K. The base K level was associated with the lowest values for most morphological variables, including plant height (PH), mainstem nodes (MSN), leaf area, and dry weight at 30 DAS and 60 DAS. However, soil K did not affect RN population counts (RC). Additionally, soil K did not influence the rate of change in growth variables among genotypes. The resistant genotype 08SS110-NE06.OP showed greater growth in terms of time to first true leaf, PH, MSN, and above-ground dry weights compared to the commercially available susceptible genotype. No interaction between K and RN or genotype and RN was found in early season cotton growth. However, RC in pots of resistant genotypes was less than in pots of susceptible genotypes. Our research on the early season growth response to soil K by novel, RN-resistant genotypes and susceptible genotypes contributes to the development of improved RN resistance and fertilization management in cotton.

Effect of growth stage, cultivar, and root wounding on disease development in cotton caused by Fusarium wilt race 4 (Fusarium oxysporumf. sp.vasinfectum)

AbstractFusarium wilt caused by soil‐borne fungusFusarium oxysporumf. sp.vasinfectumrace 4 (FOV4) is an early season disease causing root rot, and seedling wilt and death. However, it was unknown if cotton (Gossypiumspp.) growth stages and root wounding affected genotypic responses to FOV4. The objectives of this study were to investigate the effects of cotton growth stage, cultivar, and root wounding on FOV4‐associated disease development at 7‐, 14‐, 21‐, and 28‐d post inoculation through five replicated tests in controlled environmental conditions with temperatures at 21 to 23 °C. Seedlings inoculated at the cotyledon stage incurred the highest disease incidence (DI), disease severity rating (DSR), and mortality (MR), followed by seedlings inoculated at the 1‐, 3‐, and 5‐true leaf stages in descending order. Root wounding at the cotyledon stage followed by immediate inoculation with FOV4 inoculum made all the tested cultivars and lines highly susceptible. Among the six cultivars tested, FM 2334GLT and Pima DP 359 RF were the most resistant, Pima S‐7 was highly susceptible, and Acala 1517‐08, Acala 1517–18 GLS, and Pima PHY 881 RF were susceptible. The importance of artificial inoculation at a true leaf stage with or without root wounding to identify resistance that may be undetected under field conditions was discussed.

Genetic and Transcriptome Analysis of Leaf Trichome Development in Chinese Cabbage (Brassica rapa L. subsp. pekinensis) and Molecular Marker Development

Chinese cabbage (Brassica rapa L. subsp. pekinensis) is one of the vegetables with the largest cultivated area in China and has been a great addition to the daily diet of Chinese people. A genetic map has been constructed in our previous study using the F2 population of two inbred lines of Chinese cabbage, namely "G291" (a hairy line) and "ZHB" (a hairless line), based on which a candidate gene related to trichome traits was identified on chromosome A06 with a phenotypic variance of 47%. A molecular marker was found to co-segregate with the trichome traits of the F2 population, which is in the 5'-flanking region of BrGL1, and a corresponding patent has been granted (NO. CN 108545775 B). Transcriptome analysis was carried out on the cotyledon, the first true leaf and the leaf closest to each inflorescence of F2 individuals of "G291 × ZHB" with or without trichomes, respectively. Ten pathways, including 189 DEGs, were identified to be involved in the development of trichomes in Chinese cabbage, which may be specifically related to the development of leaf trichomes. Most of the pathways were related to the biosynthesis of the secondary metabolites, which may help plants to adapt to the ever-changing external environment. DEGs also enriched the "plant-pathogen interaction" pathway, which is consistent with the conclusion that trichomes are related to the disease resistance of plants. Our study provides a basis for future research on the occurrence and development of trichomes in Chinese cabbage.

Cytological, genetic and transcriptomic characterization of a cucumber albino mutant.

Photosynthesis, a fundamental process for plant growth and development, is dependent on chloroplast formation and chlorophyll synthesis. Severe disruption of chloroplast structure results in albinism of higher plants. In the present study, we report a cucumber albino alc mutant that presented white cotyledons under normal light conditions and was unable to produce first true leaf. Meanwhile, alc mutant could grow creamy green cotyledons under dim light conditions but died after exposure to normal light irradiation. No chlorophyll and carotenoid were detected in the alc mutant grown under normal light conditions. Using transmission electron microscopy, impaired chloroplasts were observed in this mutant. The genetic analysis indicated that the albino phenotype was recessively controlled by a single locus. Comparative transcriptomic analysis between the alc mutant and wild type revealed that genes involved in chlorophyll metabolism and the methylerythritol 4-phosphate pathway were affected in the alc mutant. In addition, three genes involved in chloroplast development, including two FtsH genes and one PPR gene, were found to have negligible expression in this mutant. The quality of RNA sequencing results was further confirmed by real-time quantitative PCR analysis. We also examined 12 homologous genes from alc mutant in other plant species, but no genetic variation in the coding sequences of these genes was found between alc mutant and wild type. Taken together, we characterized a cucumber albino mutant with albinism phenotype caused by chloroplast development deficiency and this mutant can pave way for future studies on plastid development.

First Report of Tomato Yellow Leaf Curl Virus Infecting Upland Cotton (Gossypium hirsutum) in Alabama, USA.

Cotton (Gossypium hirsutum L.) is used as a non-host of tomato yellow leaf curl virus (TYLCV) (family Geminiviridae, genus Begomovirus) in many studies (Ghanim and Czosnek 2000; Legarrea et al. 2015; Zeidan and Czosnek 1991), but only one reports methods used to determine host-status (Sinisterra et al. 2005), and there is one contradictory report from China stating cotton is a host of TYLCV (Li et al. 2014). In October 2018, cotton was screened for the presence of begomoviruses in Elmore, Escambia and Macon Counties, AL, where infestations of its whitefly vector (Bemisia tabaci Genn.) occurred in August. DNA was extracted from fully expanded leaves from the upper 1/3 of the canopy using a DNeasy® Plant Mini Kit (QIAGEN, Hilden, Germany) and amplified with primers V324/C889 targeting a 575 bp coat protein fragment of begomoviruses (Brown et al. 2001). Five out of 200 cotton samples tested positive, and sequences recovered from three samples revealed 98-99% identity to TYLCV isolates in NCBI (Accession Nos. MT947801-03); sequences from the other two samples were of low quality and inconclusive. These samples were not available for additional tests, therefore, we proceeded to confirm host status using a monopartite clone of TYLCV-Israel (Reyes et al. 2013) reported in the US (Polston et al. 1999). All experiments were conducted in growth chambers with 16:8 light:dark cycle at 25.0℃ and 50% RH. Cotton seedlings (DeltaPine 1646 B2XF) at the 2-3 true leaf stage and tomatoes (Solanum lycopersicum L., var. 'Florida Lanai') at the 4 true leaf stage were agroinoculated at the stem tissue between the apical meristem and the first node (Reyes et al. 2013). Tomato served as a positive control; tomato and cotton mock inoculated with an empty vector were negative controls. A hole-punch was used to collect 4 leaf discs along midveins of the three, uppermost fully expanded leaves. DNA was extracted 28 days after inoculation as described above. A 390 bp segment of the intergenic region of TYLCV-A was amplified using primers PTYIRc287/PTYIRv21 (Nakhla et al., 1993). PCR results from agroinoculated plants confirmed (2/18) cotton plants, (5/5) tomatoes and (0/10) mock inoculated controls were infected with TYLCV. Whitefly transmission to cotton was confirmed using a leaf-disc bioassay for rapid testing (Czosnek et al. 1993). Bemisia tabaci MEAM-1 reared on eggplant (non-host of TYLCV) were placed on agroinoculated TYLCV-infected tomato/span> plants for a 96-h acquisition access period. Cohorts of 10 viruliferous B. tabaci were aspirated into 30mL cups each containing a 2.5cm healthy cotton leaf disc set in plant agar. After a 48-h inoculation access period, adults and their eggs were removed from the leaf discs. Leaf discs were held another 96-h before they were tested for TYLCV using the methods described above. TYLCV-infection was confirmed in (9/20) cotton leaf discs, demonstrating the viral load delivered by whiteflies was high enough to initiate local infection in cotton. No obvious begomovirus symptoms were observed on cotton plants in the field or laboratory. Field collection of samples was prompted by symptoms attributed to cotton leafroll dwarf virus (Avelar et al. 2017). TYLCV infection of cotton does not appear to be of economic importance. Additional information is needed to determine the frequency of infection in the field, specificity of TYLCV isolate x cotton genotype interactions leading to successful infection, and underlying causes of conflicting host-status reports in previously published studies.

Endophytic Metarhizium robertsii suppresses the phytopathogen, Cochliobolus heterostrophusand modulates maize defenses.

Fungi in the genus Metarhizium (Hypocreales: Clavicipitaceae) are insect-pathogens and endophytes that can benefit their host plant through growth promotion and protection against stresses. Cochliobolus heterostrophus (Drechsler) Drechsler (Pleosporales: Pleosporaceae) is an economically-significant phytopathogenic fungus that causes Southern Corn Leaf Blight (SCLB) in maize. We conducted greenhouse and lab-based experiments to determine the effects of endophytic M. robertsii J.F. Bisch., Rehner & Humber on growth and defense in maize (Zea mays L.) infected with C. heterostrophus. We inoculated maize seeds with spores of M. robertsii and, at the 3 to 4-leaf stage, the youngest true leaf of M. robertsii-treated and untreated control plants with spores of C. heterostrophus. After 96 h, we measured maize height, above-ground biomass, endophytic colonization by M. robertsii, severity of SCLB, and expression of plant defense genes and phytohormone content. We recovered M. robertsii from 74% of plants grown from treated seed. The severity of SCLB in M. robertsii-treated maize plants was lower than in plants inoculated only with C. heterostrophus. M. robertsii-treated maize inoculated or not inoculated with C. heterostrophus showed greater height and above-ground biomass compared with untreated control plants. Height and above-ground biomass of maize co-inoculated with M. robertsii and C. heterostrophus were not different from M. robertsii-treated maize. M. robertsii modulated the expression of defense genes and the phytohormone content in maize inoculated with C. heterostrophus compared with plants not inoculated with C. heterostrophus and control plants. These results suggest that endophytic M. robertsii can promote maize growth and reduce development of SCLB, possibly by induced systemic resistance mediated by modulation of phytohormones and expression of defense and growth-related genes in maize.

USE OF BITUMEN-TREATED FABRIC MULCH DURING FIRST YEAR REPLANTING OF IMMATURE OIL PALMS

The use of empty fruit bunch (EFB) mulching in oil palm replants has for decades been implemented as best practice across the industry. In this study, several trials were initiated to evaluate the effectiveness of bitumen-treated fabric mulch (BFM) as an alternative for EFB mulching on oil palm growth performance in replants. The trial was conducted in Jeleta Bumi Estate, Sabah for 12 months. The treatments evaluated were mulching using BFM with a total quantity of first-year fertiliser applied underneath (T1) and normal EFB mulching with the standard bi-monthly manuring programme (T2). The treatments were arranged using randomised complete block design (RCBD) with four replications. The palms’ rachis length, petiole cross-section, and total fronds were measured 12 months after planting to calculate the relative leaf area (RLA), true leaf area (TLA), and leaf area index (LAI). Leaves from frond number nine were sampled for nutrient analysis. Concurrently, these treatments were replicated at a semi-commercial scale in five estates totalling 466.36 hectares under T1. Generally, there was no significant difference (P>0.05) in all parameters measured for both vegetative performance and leaf nutrients between T1 and T2. Additionally, box plot analysis indicated a uniform growth pattern across treatments from the calculated RLA, TLA, and LAI. Cost-benefit analysis indicated a saving of up to 62 per cent at 12 months after planting. This includes costs of EFB transportation, weeding and manuring rounds. Concomitantly, labour dependency could be further reduced, particularly of interest under current industry labour shortages. Response by users highlighted in reduced road maintenance, minimised rhinoceros beetle damage and lower frond scorching.

La imbibición de semillas en solución con microorganismos eficientes mejora el desarrollo de plántulas de Daucus carota L.

Efficient Microorganisms (EM) are used in agricultural production to obtain food free of agrochemicals, constituting an alternative that allows to produce at low cost and in a sustainable way, acquiring relevant importance especially in decisive processes such as the emergence and germination of seeds.This study evaluates the effects seed soaking time ofD. carota seeds in a 2% EM solution on the first phenological stages of the plant. Seeds of the Chantenay Royal variety were used, and clay loam textured soil as substrate. The experiment included three treatments (15, 30, and 45 minutes of seed soaking time) and a control (no soaking in EM) in a completely randomized design (DCA). Five variables of plant height were evaluated (unfolding cotyledons, when the first four true leaves appeared) two of cotyledon length and four with respect to the length of leaves up to the fourth true leaf. Through data analysis it was established that five of the 11 variables under study had statistical significance. The results allow us to conclude that the soaking time of seeds in a solution with efficient microorganisms could significantly improve the development of D. carota seedlings, from the main stage 00 to the main stage 14.

Sulfate-TOR signaling controls transcriptional reprogramming for shoot apex activation.

Plants play a primary role for the global sulfur cycle in the earth ecosystems by reduction of inorganic sulfate from the soil to organic sulfur-containing compounds. How plants sense and transduce the sulfate availability to mediate their growth remains largely unclear. The target of rapamycin (TOR) kinase is an evolutionarily conserved master regulator of nutrient sensing and metabolic signaling to control cell proliferation and growth in all eukaryotes. By tissue-specific Western blotting and RNA-sequencing analysis, we investigated sulfate-TOR signal pathway in regulating shoot apex development. Here, we report that inorganic sulfate exhibits high potency activating TOR and cell proliferation to promote true leaf development in Arabidopsis in a glucose-energy parallel pathway. Genetic and metabolite analyses suggest that this sulfate activation of TOR is independent from the sulfate-assimilation process and glucose-energy signaling. Significantly, tissue specific transcriptome analyses uncover previously unknown sulfate-orchestrating genes involved in DNA replication, cell proliferation and various secondary metabolism pathways, which largely depends on TOR signaling. Systematic comparison between the sulfate- and glucose-TOR controlled transcriptome further reveals that TOR kinase, as the central growth integrator, responds to different nutrient signals to control both shared and unique transcriptome networks, therefore, precisely modulates plant proliferation, growth and stress responses.

Effect of plant growth regulators on growth, yield and quality attributes of watermelon (Citrullus lanatus Thunb.)

Plant growth regulators are called as magic chemicals which are new generation agrochemicals. Exogenous application of plant growth regulators in small quantity can alter the sequence of male and female flowers, if applied at 2 or 4 leaf stages, the critical stage at which the suppression or promotion of either sex is possible. Therefore, a field experiment was carried out during Rabi, 2021 at Horticulture Research Farm, M.S. Swaminathan School of Agriculture, Centurion University of Technology and Management, Parlakhemundi, Odisha to study the influence of plant growth regulators on growth, yield and quality attributes of watermelon.Theexperiment was laid out under randomized block design with nine treatments namely 2, 4-D (25 and 50 ppm), NAA (100 and 150 ppm), GA3 (30 and 40 ppm), TIBA (20 and 25 ppm) and control (distilled water)replicated thrice. Two sprays of plant growth regulators were done at 2nd and 4th true leaf stages. The results revealed that, growth characters such as length of the main creeper (2.08 m), number of sub creepers per plant (4.40) and chlorophyll content (61.93 and 48.91 at 30 and 60 DAS) were highest in treatment (GA3 @ 40 ppm). The chlorophyll content at 90 DAS was highest (21.39) in treatment (NAA @ 100 ppm). The highest fruit yield plant-1 (17.51 kg) and fruit yield per hectare (44.17 t) was recorded in treatment (GA3 @ 40 ppm). The quality attributes such as Total Soluble Solid (TSS) (10.66%) and total sugars (15.03 %) were noted highest in treatment (GA3 @ 40 ppm). Among the different plant growth regulators spraying of GA3 @ 40 ppm found effective in enhancing the growth, yield and quality attributes of watermelon.

Anti-quorum sensing, antibiofilm, and antibacterial activities of extracts of Centella asiatica L. leaves, and in vitro derived leaves-calli through tissue culture: a potential for biofouling-prevention

Extracts of Centella asiatica leaves (LEs), and in-vitro leaf-calli (CEs), were investigated for antibacterial, antibiofilm, and anti-quorum sensing activities. Ethyl acetate extracts from leaves (EALE), leaf-calli (EACE), methanolic extracts from leaves (MELE), and leaf-calli (MECE) showed antibacterial activity; the minimum inhibitory concentrations (MICs) of LEs and CEs ranged from 0.312–2.50 mg ml−1 and 0.625 − 2.50 mg ml−1, respectively. The MICs of EALE and EACE were 2.50 mg ml−1, each, for C. violaceum 12742, and P. aeruginosa PAO1. At sub-MIC levels, EALE and EACE showed anti-quorum sensing (anti-QS) activity, demonstrated by concentration dependent pigment inhibition of C. violaceum 12742. Similarly, EALE and EACE inhibited QS-controlled virulence factors in P. aeruginosa PAO1 (biofilm, pyocyanin, and pyoverdin); again, the inhibition was concentration-dependent. The best effect was at immediate sub-MIC concentration i.e. 1250 µg ml−1. GC-MS analyses revealed the presence of compound 9,12-Octadecadienoic acid, and in silico docking study suggested interactions with QS-receptors CviR', LasI, and LasR proteins for anti-QS activity.

Increasing the yield of melon in a greenhouse at vegetative grafting on vegetable marrow rootstocks

In Uzbekistan, there is a demand of the population for fresh melon fruits during the off-season. In the Research Institute of Vegetable, Melon Crops and Potato for the first time studies were carried out, when grown in a greenhouse, on the vegetative grafting of melon’s Zarkhal variety on the vegetable marrow varieties used as rootstocks. The aim of the research was to study the effect of vegetable marrow rootstocks on the variability of economically valuable traits of the Zarkhal melon variety and to identify promising combinations of vegetable marrow rootstocks that increase the yield and quality of melon fruits.Methods. The studies were carried out in accordance with the guidelines of the World Vegetable Center. As a control, ungrafted plants of the Zarkhal melon variety were used. For comparison with the control, plants of this variety were grafted onto their own plants. Also, plants of the melon variety Zarkhal (scion) were grafted in combinations on 10 varieties of vegetable marrow, which served as rootstocks. Vegetative grafting of melon on vegetable marrow rootstocks was carried out “in a split” in the phase of the first true leaf when the stem diameter reached 4.1–4.3 mm and plant height 4.4–5.9 cm.Results. In comparison with the control, in combinations of grafting the Zarkhal melon variety onto the Grecheskiye 110, Unumdor, Delicates and Skvorushka varieties of vegetable marrow, the flowering of paternal and female flowers, the onset of fruit formation was observed 2 days earlier. In the same combinations, fruit ripening was observed on 81-82 days, which is 4-5 days earlier than the control (86 days). They also had the tallest plants (203-205 cm), the plants formed 2-4 leaves more than the others. Marketable yields between combinations ranged from 7.89 to 9.75 kg/m2 . The melon variety Zarkhal, grafted onto its own plants, lagged behind the control in all phases of development and yield. The early yield in combinations was from 3.95 to 5.75 kg/m2 and amounted to 53-59% of the yield. The average fruit weight varied from 785 to 810 g.