Plant Growth Regulator Treatments Research Articles

Spring nitrogen and plant growth regulator effects on seed yield of orchardgrass

AbstractOrchardgrass (Dactylis glomerata L.) is an important forage seed crop, but unlike other cool‐season grasses, seed yields have not increased over time. Seed yield increases in orchardgrass may be possible with plant growth regulators (PGRs) such as trinexapac‐ethyl (TE) and chlormequat chloride (CCC). Field trials were conducted at Hyslop Experimental Farm near Corvallis, Oregon, over three crop years (2017–2019) to examine the effects of spring nitrogen (N) and PGRs on seed production characteristics in orchardgrass. Spring N treatments included 0, 112, 157, and 202 kg N ha−1 and PGR applications were timed using the BBCH (Biologische Bundesanstalt, Bundessortenamt und Chemische Industrie) scale. Four PGR treatments included an untreated control, 210 g TE ha−1 at BBCH 32, 210 g TE ha−1 at BBCH 51, and 105 g TE ha−1 + 1500 g CCC ha−1 at BBCH 32. An interaction of spring N and PGR increased seed yields in 2 years, while spring N and PGR increased seed yield independently in the other year. The combination of TE and CCC PGRs did not increase seed yield over TE alone. Seed yield increases from spring N were due to an increase in seed number m−2, while increases in seed yield attributable to PGRs were the result of increased seed number m−2 and harvest index. This study suggests that the combination of 112 kg ha−1 spring N and 210 g ha−1 TE PGR is the best practice to maximize seed yield in orchardgrass.

Plant growth regulator effects on red fescue seed crops in diverse production environments

AbstractStrong creeping red fescue (Festuca rubra L. spp. rubra Gaudin) is a cool‐season perennial turfgrass widely used in temperate and subalpine regions around the globe. Although creeping red fescue turf is tolerant of shade, low fertility acidic soils, and drought conditions, creeping red fescue seed crops grown in optimal growing environments can lodge, ultimately reducing yield in regions where this important turfgrass is grown for seed. To address this issue, we investigated the effects of two plant growth regulators (PGRs), chlormequat chloride (CCC) and trinexapac‐ethyl (TE), on plant height, lodging, and seed yield of strong creeping red fescue over 9 site‐years in the Peace River region of western Canada. The study encompassed 6 site‐years with first‐year stands and 3 site‐years with second‐year stands. The PGRs were applied alone and in a TE + CCC mixture at the two‐node (BBCH 32–33, where BBCH is Biologische Bundesanstalt, Bundessortenamt and Chemische Industrie) and early head emergence (BBCH 51–52) growth stages in first‐ and second‐year stands, respectively. The application of TE, CCC, and their mixture resulted in a differential decrease in lodging and an increase in seed yield in first‐year stands. However, PGRs applied at BBCH 51–52 on second‐year stands had no effect on seed yield but reduced plant height and lodging. This study found a negative correlation between seed yield and lodging. Among the PGR treatments, the CCC + TE mixture was the most effective in reducing lodging and increasing seed yield of strong creeping red fescue.

Feasible biosynthesis of biologically active metabolites in in vitro culture of Macrotyloma uniflorum

Macrotyloma uniflorum, commonly called “Horse gram” is an underutilized pulse crop recognized for its great nutritional significance and a broad range of biological properties. There have been no in vitro studies for the biosynthesis of enhanced bioactive metabolites in the callus culture of M. uniflorum. In the study reported here, we have designed a feasible protocol for high-frequency callus induction and maintenance utilizing a leaf as an explant grown on MS media enriched with various concentrations of different plant growth regulators (PGRs) including α-naphthalene acetic acid (NAA), 6-benzylaminopurine (BAP) and thidiazuron (TDZ) either alone or in combination. Among all the tested PGRs, NAA alone resulted in high-frequency callus induction (97%), and maximum biomass accumulation (Fresh weight (FW): 200 g/L: Dry weight (DW): 20.4 g/L). Moreover, hormonally optimized callus cultures exhibit maximum production of phenolic compounds (166.6 mg/L) and flavonoid compounds (351.6 mg/L). The antioxidant potential of calli extracts was also determined by utilizing various antioxidant activities. Maximum antioxidant activities ((2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid)) ABTS = 497.9; TEAC μM; (Ferric reducing antioxidant power) FRAP = 823 TEAC μM; (Cellular Antioxidant Activity) CAA: 58.2%) were recorded in leaf-derived calli supplemented with different PGRs treatments. High-performance liquid chromatography (HPLC) analysis further revealed maximum biosynthesis of caffeic acid (1.63 mg/g DW), gallic acid (8.92 mg/g DW), kaempferol (0.71 mg/g DW), myricetin (0.39 mg/g DW), apigenin (0.64 mg/g DW) at 10 mg/L BAP and isorhamnetin (0.68 mg/g DW) at 1 mg/L TDZ + 10 mg/L NAA. The objective of this study was to explore in vitro biosynthesis of enhanced bioactive metabolites in the callus culture of M. uniflorum, leveraging a feasible protocol for high-frequency callus induction and maintenance. The results showcase the remarkable efficacy of NAA in callus induction and biomass accumulation, highlighting the hormonally optimized callus cultures as a potent source for enhanced biosynthesis of bioactive metabolites, paving the way for further applications in pharmaceutical and commercial industries.

Assessment of Cassava Pollen Viability and Ovule Fertilizability under Red-Light, 6-Benzyl Adenine, and Silver Thiosulphate Treatments.

Understanding pollen and ovule fertility as factors influencing fruit and seed set is important in cassava breeding. Extended daylength with red light (RL) and plant growth regulators (PGRs) have been used to induce flowering and fruit set in cassava without any reference to effects on pollen viability or ovule fertilizability. This study investigated the effects of field-applied RL and PGR on pollen viability and ovule fertilizability. Panels of cassava genotypes with early or moderate flowering responses were used. RL was administered from dusk to dawn. Two PGRs, 6-benzyl adenine (BA), a cytokinin and silver thiosulphate (STS), an anti-ethylene, were applied. Pollen viability was assessed based on pollen grain diameter, in vitro stainability, in vivo germinability, ovule fertilizability, and ploidy level. Treating flowers with RL increased the pollen diameter from 145.6 in control to 148.5 µm in RL, 78.5 to 93.0% in stainability, and 52.0 to 56.9% in ovule fertilizability in treated female flowers. The fruit set also increased from 51.5 in control to 71.8% in RL-treated female flowers. The seed set followed a similar trend. The ploidy level of pollen from RL-treated flowers increased slightly and was positively correlated with pollen diameter (R2 = 0.09 *), ovule fertilization (R2 = 0.20 *), fruit set (R2 = 0.59 *), and seed set (R2 = 0.60 *). Treating flowers with PGR did not affect pollen diameter but increased stainability from 78.5% in control to 82.1%, ovule fertilizability from 42.9 to 64.9%, and fruit set from 23.2 to 51.9% in PGR-treated female flowers. Combined BA + STS application caused the highest ovule fertilizability, fruit, and seed set efficiency. These results show that RL and PGR treatments increase pollen viability and ovule fertilizability. This is important for planning pollination strategies in cassava breeding programmes.

Effect of Preharvest Treatment Using Jasmonic Acid and Methyl Jasmonate on the Physicochemical Properties and Antioxidant Activities of Red-fleshed Dragon Fruit (Hylocereus polyrhizus L.)

This study investigated the effect of exogenous plant growth regulators (PGR), namely jasmonic acid (JA) and methyl jasmonate (MeJA), on the physicochemical properties of flesh and peels of red-fleshed dragon fruit (Hylocereus polyrhizus). The fruit was sprayed with 100 and 1,000 ppm of JA and MeJA at 15 and 22 days of anthesis and harvested after 35 days. Then, the flesh and peels were analyzed for total soluble solids (TSS), total betacyanins, betanin, total phenolics (TP), total flavonoids (TF), and color characteristics. The fruit peels contained significantly higher (p<0.05) TP and antioxidant activities compared to flesh. No significant difference was detected between the variables in the peels, except for significantly higher (p<0.05) of total betacyanins (~295.6 and ~299.9 mg/100 g) and TP (~614.1 and 566.1 mg GAE/100 g) were recorded in control and 100 ppm MeJA, respectively. In the flesh, 1,000 ppm MeJA-treated fruit possessed the highest total betacyanins (~139.2 mg/100 g), betanin (~356.0 mg/g), TP (~244.9 mg GAE/100 g), TF (~329.0 mg CE/100 g), Trolox equivalent antioxidant capacity (TEAC) (63.2 µmol TE/g) and reducing power (~21.5 µmol TE/g). Overall, 1,000 ppm MeJA was more effective in enhancing the accumulation of bioactive compounds and antioxidant activities in the flesh of red-fleshed dragon fruit compared to other PGR treatments.

Promising and Failed Breeding Techniques for Overcoming Sterility and Increasing Seed Set in Bananas (Musa spp.)

Most banana improvement programs are restricted to using a sub-set of edible landraces for sexual hybridization as the majority are female sterile. This results from an array of factors that work in tandem and lead to sterility. Use of pollination germination media (PGM) during pollination significantly increases seed set, but it is a very small fraction compared to the potential seed set. This research therefore explored early pollination (a day before anthesis), evening pollination, saline treatment, plant growth regulators (PGRs) treatment, and ovule culture as potential techniques for overcoming sterility in bananas. Early and evening pollinations did not increase seed set because of immature flowers and a mismatch of male and female flower opening, respectively (t-prob. = 0.735 and 0.884). Immersion of bunches in a saline solution before pollination and ovule culture also did not overcome pollination barriers. Auxin antagonists (TIBA and salicylic acid) increased seed set, though their respective increases were not statistically significant (t-prob. = 0.123 and 0.164, respectively). The use of auxin antagonists shows great potential for overcoming pollination barriers in bananas. However, application rates and time of application have to be optimized and used holistically with other promising techniques, such as use of PGM.

Effect of Foliar Application of Selected Plant Growth Regulators on Growth and Yield of Soybean [Glycine max (L.) Merrill

Background: Soybean (Glycine max), a prized oilseed crop known for its nutritional richness, is the focus of a study aiming to boost production with minimal environmental impact. The research explores the application of plant growth regulators (PGRs), specifically Gibberellic Acid (GA3), Kinetin and Salicylic Acid, in field experiments during the kharif seasons of 2022 and 2023 in Beed, India. Methods: The study applied Gibberellic Acid (GA3), Kinetin and Salicylic Acid at different concentrations in field experiments. A comprehensive analysis of growth and yield attributes, including plant height, primary branches, Leaf Area Index (LAI), root nodules and Crop Growth Rate (CGR), was conducted to assess the influence of PGR treatments on soybean growth. Yield attributes such as pod count, pod weight, seed count per pod and 100-seed weight were scrutinized to understand their effects on soybean productivity. Result: The study highlighted significant effects of PGR treatments on soybean growth and yield. Notably, Kinetin at 500 ppm promoted the tallest plants, while GA3 at 200 ppm resulted in the shortest. Kinetin at 100 ppm increased primary branches and Salicylic Acid at 50 ppm exhibited the highest LAI and abundant root nodules. Kinetin at 500 ppm and Salicylic Acid at 50 ppm showed higher CGR, indicating efficient crop growth. For yield, Kinetin at 500 ppm excelled in pod count and weight. GA3 at 100 ppm was identified as the most effective PGR for enhancing various growth parameters and soybean seed yield, suggesting the potential of PGRs in sustainable cultivation, reducing reliance on chemical inputs.

Reguladores de crescimento influenciam a altura e a partição de biomassa de plantas de mamona

ABSTRACT Castor (Ricinus communis) is a drought-resistant oilseed crop. This study evaluated five plant growth regulators (PGR) on their capacity to influence stem elongation of castor plants growing under shade and measured side effects on the biomass allocation among leaf, stem, and roots. The experiment had 220 castor plants of the cultivar AKB 02, on a completely randomized design and four replicates. The plants were kept under artificial shade and treated with 11 doses of PGR, applied in the first day after emergence. Eight plants were exposed to full sun radiation without PGR treatment. The plant height was measured daily, and the plants were harvested for weighing the final biomass. The data was subjected to multiple linear regression. The shade promoted stem elongation and reduced biomass accumulation in all compartments. The height growth was restricted by trinexapac-ethyl, mepiquat chloride, and chlormequat chloride. Gibberellin promoted stem elongation in addition to the shade effect. Paclobutrazol did not influence stem elongation, but it favored biomass accumulation and increased the stem density. Gibberellin promoted allocation to stem replacing leaf biomass; trinexapac-ethyl promoted root replacing stem and leaf biomass; mepiquat and chlormequat chloride promoted stem in detriment of leaf biomass. In conclusion, plant growth regulators may be effective to restrict height growth of castor plants, but they can also disturb the biomass allocation among root, stem, and leaves.

Matabolomic Changes Induced by 6-Benzylaminopurine in Polygonatum cyrtonema

Polygonatum cyrtonema Hua (family Asparagaceae) is an endemic plant in China that is valuable for its edible and medicinal uses. Plant growth regulators (PGRs) are natural or synthetic compounds that can regulate plant development and metabolism effectively. To explore potential applications of PGRs for improving the yield and bioactivity of this plant, four PGRs, including gibberellic acid (GA3), 6-benzylaminopurine (6-BA), naphthaleneacetic acid (NAA) and 24-epibrassinolide (EBL), were used in this study and sprayed on the growing seedlings of P. cyrtonema. All of these PGRs did not significantly affect the growth rate of P. cyrtonema, but they had varying effects on the polysaccharide and saponin content in the rhizome. NAA and 6-BA positively affected the polysaccharide content, while most PGR treatments negatively affected the saponin content. Widely targeted metabolomic analysis based on UPLC-MS/MS was conducted and revealed 101 differential metabolites in response to 6-BA, most of which were flavonoids, steroids and lipids. Most of the significantly changed flavonoids decreased under the 6-BA treatment. The study provides insights into the potential use of PGRs for improving the quality of P. cyrtonema, particularly in regulating the content of bioactive compounds.

EFFICIENT CLONAL PROPAGATION OF GUAVA CULTIVARS BY MINI SOFTWOOD CUTTINGS

Guava (Psidium guajava L.) is commercially propagated by seeds in Punjab and vegetative propagation systems are lacking. Propagation by stem cuttings is handicapped by the non-availability of plant material in bulk for cuttings and season dependency. Hence, juvenile mini softwood (MSW) shoot cuttings (3"-4") of Gola (Round) cultivar having two to three nodes were treated with plant growth regulators (PGRs) including indole butyric acid ‘IBA’ or naphthalene acetic acid ‘NAA’ in combinations with benzyl aminopurine ‘BAP’ and planted in sand, silt and coco peat (40:40:20 v/v) under CRD layout for PGR optimization. Cuttings treated with BAP and IBA (2 mgL-1 + 3 mgL-1) started early sprouting in 8 days and induced a greater number of branches (5-6), number of leaves (11), number of roots (6-7) and long roots (14 cm). Whereas, sprout length was higher up to 14 cm in cuttings treated with BAP and IBA (3 mgL-1 + 1 mgL-1). In the second part of the study, application of the optimized PGR treatment of BAP and IBA (2 mgL-1 + 3 mgL-1) to MSW cuttings of different commercial strains of cultivars Gola (Round) and Surahi (Pyriform) showed a better number of roots (5, 4), root length (13 cm, 11 cm), bud sprouting (100% and 80%) and number of nodes (5 each) in Gola (Sadabahar ‘G1’) and Surahi (Sindhi Bao ‘S2’), respectively. The rooted cuttings were maintained under standard growth room conditions and higher humidity till proper plant growth and the established plantlets were transferred to green house. This study established an efficient clonal propagation system using MSW cuttings thus reducing the plant material and PGRs required for mass multiplication of elite guava cultivars. Keywords: Auxin, cytokinin, softwood cuttings, shoot, rooting.

The difference in leaves production, protein and calcium of Moringa oleifera under modification planting media, application of PGR and nitrogen

Moringa has many ingredients of nutrients that are beneficial for food sources and nutrients that have not been widely cultivated. The nutritional content, benefits and high demand for Moringa abroad will open large opportunities for exporting Moringa flour. Foods full of nutrition will support the maintenance of good public health. For this reason, it is necessary to study and research cultivation techniques that produce high Moringa leaves and can be available sustainably. Production of Moringa leaves as a source of secondary metabolites can be increased by modifying the planting media and applying Plant Growth Regulator (PGR) and Nitrogen. The study used Split Split Plot Design with the main plot immersion by PGR, consisting of 3 types, namely: G1 (Fresh water), G2 (Coconut water), and G3 (GA3). The subplot was the treatment of planting media with two types: M₁ (soil: sand: manure = 1:1:2); M₂ (soil: sand: manure = 1:2:1). The sub subplots were N (urea) fertilizer, with four levels: N0 (0 g/plant); N1 (5 g/plant); N₂ (10 g/plant); and N₃ (15 g/plant). Each treatment combination goes over three times. The agronomic parameters observed were plant height, the number of leaves, fresh crop weight, and root volume, and the biochemical parameters observed were chlorophyll, protein, and calcium levels. The composition of the planting media caused significant differences in plant height at 4, 6, and 10 weeks after planting (WAP), the number of leaves at 4 WAP, and root length at 10 WAP. Growth Regulators significantly affected plant height at 4, 6, and 10 WAP, the number of leaves at 4 WAP, and root length at harvest. Nitrogen fertilization caused significant differences in plant height at 4, 6, and 10 WAP, volume, and root length at harvest (10 WAP). The combination of Planting media, PGR, and Nitrogen treatments caused significant differences in plant height at 4, 6, and 10 WAP and the number of leaves at 6 WAP. Laboratory analysis in this study showed high calcium and protein in Moringa leaves.

Effects of Low-Dose Kinetin, 2,4-D and Monochromatic Light Conditions on Flavonoid Content in Callus Culture of Dioscorea esculenta

The callus culture of Dioscorea esculenta is a potential strategy to produce efficacious bioactive compounds in multiplied production. It can be carried out by applying plant growth regulators (PGR) and environmental modification, including light-emitting diodes (LEDs) exposure. This study aims to investigate the impact of PGR and the stimulatory effect of LEDs on flavonoid profiles in D. esculenta callus culture. The study was conducted using combination variations of 2,4-D (0.5 and 1 ppm), kinetin (0.5 and 1 ppm), and LEDs stimulatory conditions (light and dark). The results showed that flavonoids are the dominant compounds found in lesser yam cultures, which reached more than 78 % in all treatments-specifically, adding 0.5 ppm kinetin and 0.5 ppm 2,4-D to D. esculenta callus cultures significantly increased flavonoids production compared to single PGR treatment. This shows there is a synergistic activity induced by 2,4-D and kinetin. Furthermore, monochromatic light exposure also significantly affects flavonoid production. Analysis of 5 main flavonoids, isoflavones, flavanones, kaempferols, quercetin, and epigallocatechin, proved that monochromatic light significantly increased flavonoids production compared to callus cultures were kept in a growth room under 24 °C temperature in the dark condition. This study confirmed that equally combining 0.5 ppm of 2,4-D and 0.5 ppm of kinetin under monochromatic LEDs increases flavonoid production in D. esculenta callus cultures. Further research must be conducted to describe how the bioactive compound synthesis signaling pathway involving PGR and monochromatic LEDs improves plant quality in the pharmaceuticals’ role. HIGHLIGHTS Kinetin and 2,4-D at the same concentration of 0.5 ppm is an optimal combination to increase secondary metabolite production in esculenta callus culture Combining kinetin and 2,4-D at low concentrations significantly increased flavonoids, especially kaempferol, isoflavone, quercetin, flavanone, and epigallocatechin in esculenta callus culture Light condition significantly affects the production of flavonoids, especially kaempferol, isoflavone, quercetin, flavanone, and epigallocatechin There is evidence that kinetin and 2,4-D under light conditions work in a synergic effect on the biosynthesis of secondary metabolite compounds in esculenta callus cultures GRAPHICAL ABSTRACT

Antioxidant and Antitumor Potential of Micropropagated Balkan Endemic Sideritis scardica Griseb

Sideritis scardica Griseb. is a critically endangered Balkan endemic species, known for its antioxidant, neuroprotective and anti-inflammatory properties. The aim of the present study was to detail an efficient protocol for the micropropagation of S. scardica. In vitro cultures were initiated from the shoot tips of 40 days-old in vivo seedlings and the effects of different plant growth regulator treatments were examined. A Murashige and Skoog nutrient medium (MS) containing 1 mg/L zeatin and 0.1 mg/L indole-3-acetic acid (IAA) proved to be the most efficient for shoot multiplication as it produced quality, vigorous shoots with a mean number of six shoots per explant. For the first time, the antioxidant and antitumor activities of extracts from in vitro-obtained plants were evaluated. In vitro cultivated plants grown in the field revealed a higher total polyphenol content (3929.1 ± 112.2 mg GAE/100 g vs. 3563.5 ± 52.8 mg GAE/100 g) and higher ORAC antioxidant activity (1211.6 ± 27.3 µmol TE/g vs. 939.9 ± 52.4 µmol TE/g) than in situ cultivated plants. A comparison of the antitumor activities of extracts from in vitro propagated shoots, field-grown in vitro-obtained plants and in situ plants on HeLa (cervical adenocarcinoma), HT-29 (colorectal adenocarcinoma) and MCF-7 (breast cancer) human cancer cell lines showed that in vitro propagated shoots had a significant concentration-dependent cytotoxic effect on the cervical adenocarcinoma cell line HeLa, while the field-grown in vitro-obtained and in situ-collected samples induced the highest reduction in the viability of the mammary carcinoma cell line MCF-7. In both cases, the cells of the control non-tumor cell line, BALB/3T3, were significantly less affected. The results showed that the in vitro multiplication protocol ensured the obtainment of numerous plants with antioxidant and antitumor potential.

Effect of Plant Growth Regulators and Biofertilizer on the Yield of Fenugreek (Trigonella foenum-graecum L.)

The present investigation entitled “Effect of plant growth regulators and bio fertilizer on growth and quality of fenugreek (Trigonella foenum-graecum L.)” was carried out at the Experimental field, College of Agriculture, RVSKVV, Gwalior during 2020-21 under agro-climatic and soil conditions of Northern Madhya Pradesh. The experiment was laid out in Randomized Block Design (RBD) with three replications. Each replication consists of ten treatments of biofertilizers (viz., Rhizobium, PSB and KSB) and plant growth regulators (viz., GA3 and NAA). All the treatments were randomized separately in each replication. Result showed that the different biofertilizers (i.e. Rhizobium, PSB and KSB) and plant growth regulators (i.e. GA3 and NAA) treatments significantly influenced the yield, yield parameters and economics parameters of fenugreek. Treatment T4 (Rhizobium + NAA) gave the maximum yield, yield parameter and economic parameter it was found best treatment combination as compared to all other treatment combinations of biofertilizers and PGRs, while the minimum yield, yield parameters and economics parameters were recorded in treatment T1 (Control).

Effect of Plant Growth Regulators and Bio-Fertilizer on Growth and Quality of Fenugreek (Trigonella foenum-graecum L.)

The present investigation entitled “Effect of plant growth regulators and bio-fertilizer on growth and quality of fenugreek (Trigonella foenum-graecum L.)” was carried out at the Experimental field, College of Agriculture, RVSKVV, Gwalior during 2020-21 under agro-climatic and soil conditions of Northern Madhya Pradesh. The experiment was laid out in Randomized Block Design (RBD) with three replications. Each replication consists of ten treatments of biofertilizers viz., Rhizobium, Phosphate solubilizing bacteria (PSB) and Potassium solubilizing bacteria (KSB) and plant growth regulators viz., Gibberellic acid (GA3) and Naphthalene acetic acid (NAA). All the treatments were randomized separately in each replication. Result showed that the different biofertilizers (i.e. Rhizobium, PSB and KSB) and plant growth regulators (i.e. GA3 and NAA) treatments significantly influenced the growth and quality parameters of fenugreek. Treatment T4 (Rhizobium + NAA) gave the maximum growth, it was found best treatment combination as compared to all other treatment combinations of biofertilizers and PGRs, while the minimum growth, yield and economical parameters were recorded in treatment T1 (Control).

High-throughput MALDI-MSI metabolite analysis of plant tissue microarrays.

A novel metabolomics analysis technique, termed matrix-assisted laser desorption/ionization mass spectrometry imaging-based plant tissue microarray (MALDI-MSI-PTMA), was successfully developed for high-throughput metabolite detection and imaging from plant tissues. This technique completely overcomes the disadvantage that metabolites cannot be accessible on anintact plant tissue due to the limitations of the special structures of plant cells (e.g. epicuticular wax, cuticle and cell wall) through homogenization of plant tissues, preparation of PTMA moulds and matrix spraying of PTMA sections. Our study shows several properties of MALDI-MSI-PTMA, including no need of sample separation and enrichment, high-throughput metabolite detection and imaging (>1000 samples per day), high-stability mass spectrometry data acquisition and imaging reconstruction and high reproducibility of data. This novel technique was successfully used to quickly evaluate the effects of two plant growth regulator treatments (i.e. 6-benzylaminopurine and N-phenyl-N'-1,2,3-thiadiazol-5-ylurea) on endogenous metabolite expression in plant tissue culture specimens of Dracocephalum rupestre Hance (D.rupestre). Intra-day and inter-day evaluations indicated that the metabolite data detected on PTMA sections had good reproducibility and stability. A total of 312 metabolite ion signals inleaves tissues of D. rupestre were detected, of which 228 metabolite ion signals were identified, they were composed of 122 primary metabolites, 90 secondary metabolites and 16 identified metabolites of unknown classification. The results demonstrated the advantages of MALDI-MSI-PTMA technique for enhancing the overall detection ability of metabolites in plant tissues, indicating that MALDI-MSI-PTMA has the potential to become a powerful routine practice for high-throughput metabolite study in plant science.

Plant Growth Regulators and Activated Charcoal Selectively Affect Phenylethanoid and Flavone Glycoside Accumulation in Sideritis scardica Griseb. Tissue Culture.

Sideritis scardica Griseb. is a Balkan endemic species traditionally used for the treatment of pulmonary emphysema and angina pectoris. Recent research has also shown its phytotherapeutic potential as an anticancer and neuroprotective agent. These findings, as well as the endangered status of the species in its wild habitats, have motivated the present research on application of plant cell tissue and organ culture for the purposes of both valuable germplasm conservation and secondary metabolites production. Shoot cultures of the plant were initiated from sterile germinated seeds and the effects of activated charcoal (AC), as well benzyl adenine and 1-naphthaleneacetic acid treatments, were experimented. The phenolic profile analysis was performed by HPLC/DAD/MSn. Comparison with samples collected from wild plants in their natural habitat was performed. It was established that in vitro multiplication induced by plant growth regulators (PGRs) was accompanied by a higher impairment of leaf morphology and trichome formation, as well as by the occurrence of plantlet hyperhydricity and callus formation, as compared with the AC treatments. Shoot culture-derived plant material was shown to produce two phenylethanoids and five flavone glycosides, not detected in the wild collected plant material. In addition, the two types of in vitro culture treatments led to the stimulation of either flavone glycosides or phenylethanoids in the in vitro cultivated plants. Thus, AC stimulated, to a higher extent, flavone glycosides' accumulation, leading to an elevated flavone/phenylethanoid ratio, as compared with PGR treatments.

Flowering and fruit-set in cassava under extended red-light photoperiod supplemented with plant-growth regulators and pruning

BackgroundCassava (Manihot esculenta Crantz) is staple food and major source of calories for over 500 million people in sub-Saharan Africa. The crop is also a source of income for smallholder farmers, and has increasing potential for industrial utilization. However, breeding efforts to match the increasing demand of cassava are impeded by its inability to flower, delayed or unsynchronized flowering, low proportion of female flowers and high fruit abortions. To overcome these sexual reproductive bottlenecks, this study investigated the effectiveness of using red lights to extend the photoperiod (RLE), as a gateway to enhancing flowering and fruit set under field conditions.Materials and methodsPanels of cassava genotypes, with non- or late and early flowering response, 10 in each case, were subjected to RLE from dusk to dawn. RLE was further evaluated at low (LL), medium (ML) and high (HL) red light intensities, at ~ ≤ 0.5; 1.0 and 1.5PFD (Photon Flux Density) in µmol m−2 s−1 respectively. Additionally, the effect of a cytokinin and anti-ethylene as plant growth regulators (PGR) and pruning under RLE treatment were examined.ResultsRLE stimulated earlier flower initiation in all genotypes, by up to 2 months in the late-flowering genotypes. Height and number of nodes at first branching, particularly in the late-flowering genotypes were also reduced, by over 50%. Number and proportion of pistillate flowers more than doubled, while number of fruits and seeds also increased. Number of branching levels during the crop season also increased by about three. Earlier flowering in many genotypes was most elicited at LL to ML intensities. Additive effects on flower numbers were detected between RLE, PGR and pruning applications. PGR and pruning treatments further increased number and proportion of pistillate flowers and fruits. Plants subjected to PGR and pruning, developed bisexual flowers and exhibited feminization of staminate flowers. Pruning at first branching resulted in higher pistillate flower induction than at second branching.ConclusionsThese results indicate that RLE improves flowering in cassava, and its effectiveness is enhanced when PGR and pruning are applied. Thus, deployment of these technologies in breeding programs could significantly enhance cassava hybridizations and thus cassava breeding efficiency and impact.

Combined treatment with gibberellic acid and thidiazuron improves fruit quality of ‘Red Dream’ grape cultivar

This study was conducted to investigate the effect of treatment conditions of plant growth regulators on the marketability of ‘Red Dream’, a triploid grape. In order to achieve the purpose of this study, gibberellic acid 3 (GA3) 100 ppm single use treatment group was set as a control group. In addition, the fruit characteristics expressed when cytokinins such as thidiazuron (TDZ) or forchlorfenuron (CPPU) 2.5 ppm or 5.0 ppm mixed with GA3 100 ppm were compared with the control group. Cluster weight was commonly higher in the mixed treatment of TDZ or CPPU than in the GA3 single use treatment, and it was found that the cytokinin mixed treatment could effectively induce the enlargement of ‘Red Dream’ berries. Although the harvesting period was slightly delayed compared to GA3 single use treatment in the case of mixed treatment of GA3 and TDZ or CPPU, there was no inhibition of coloration, soluble solid sugar content and functionality, which are important indicators of marketability. In particular, in the GA3 100 ppm + TDZ 5 ppm treatment group, where the enlargement of fruits was the largest, the occurrence rate of non-commercial berry was also found to be the lowest. Therefore, it is expected to contribute to strengthening the marketability of ‘Red Dream’ if such plant growth regulator treatment condition is applied during cultivation.

Effect of Plant Growth Regulators on Creeping Bentgrass during Heat, Salt, and Combined Stress

Creeping bentgrass (Agrostis stolonifera L.) is a turfgrass species that is widely used on golf courses throughout the United States. In field settings, plants are often subjected to more than one stress at a time, and studying stresses independently is likely insufficient. Stresses, such as heat stress and salt stress, can affect plant hormone levels and, in turn, plant hormone levels can affect how well the plant tolerates stress. The objectives of the experiments were to determine if the levels of heat stress and salt stress used would be detrimental to creeping bentgrass health, and if applying plant growth regulators could improve plant health during stress. During the first experiment, creeping bentgrass was transplanted to hydroponics systems in two different growth chambers. One chamber was set to have day and night temperatures of 35 °C and 30 °C (heat stress), respectively, and the other had day and night temperatures of 25 °C and 20 °C, respectively. Within each chamber, one block received a 50 mM NaCl treatment (salt stress) and the other did not (control). The stress treatments were applied for 14 days. Results of the first experiment indicated that the treatments were sufficient to negatively affect creeping bentgrass growth and health as indicated by fresh shoot and root weights, tillering, electrolyte leakage, and total chlorophyll content (TCC). There were significant interactions of temperature × salt level detected for shoot and root weights and electrolyte leakage. Plants that were exposed to both heat stress and salt stress were more negatively affected than plants exposed to either heat stress or salt stress alone for all metrics except for tillering. The presence of salt reduced tillering regardless of the temperature regimen. During the second experiment, plants were treated the same, but the plant growth regulator (PGR) treatments were also applied. The PGR treatments consisted of two different gibberellic acid (GA) synthesis inhibitor products, 2,4-dichlorophenoxyacetic acid, two different rates of aminoethoxyvinylglycine (AVG), an ethylene synthesis suppressor, and plants that were not treated with the PGR. In addition to the measurements of plant health and growth, dry shoot and root weights were measured. For the TCC, there was a two-way interaction between temperature × PGR treatment. For electrolyte leakage, there was a three-way interaction between temperature × salt level × PGR treatment. Combined heat stress and salt stress negatively affected all plants regardless of PGR treatment, but there were differences between PGR treatments. Plants treated with AVG exhibited improved health and growth compared with the other PGR treatments. These plants had the highest shoot and root masses. Plants treated with GA synthesis inhibitors had the lowest shoot and root masses as well as the lowest TCC when subjected to stress.