Types Of Plant Growth Regulators Research Articles

Uptake, translocation and metabolism of N-phenyl-phthalamic acid in pepper and wheat

N-phenyl-phthalamic acid (PPA) is a new type of plant growth regulator that is widely utilized on fruit trees and crops in China. Understanding the physical and chemical behavior of PPA in plants is crucial for formulating application strategies and predicting potential environmental risks. This study investigated the uptake, translocation, and metabolism processes of PPA in pepper and wheat after different treatments. The roots of pepper and wheat can rapidly absorb and translocate PPA to the stems and leaves. In the 100 μg/mL treatment group, the PPA concentrations in the roots, stems, and leaves of pepper reached their maximum within 10 h after treatment, with 19.8, 2.4, and 2.9 mg/kg, respectively. Similar results can be detected in wheat. PPA can also be translocated from treated leaves to the entire plant in both pepper and wheat, and it tends to accumulate more in the upper leaves, with PPA mass percentages of 36.4 % and 36.9 % in the upper leaves of wheat and pepper, respectively, at 96 h. PPA is easily degradable in the plant body and seeds (the t1/2 was 1.3–3.3 d). The above results indicate that PPA is easily absorbed by the roots, leaves, and seeds of crops and, undergoes bidirectional translocation, and is easily degradable, which means that PPA can be applied in various ways and poses a relatively low risk to food safety.

Deciphering physiological and transcriptional mechanisms of maize seed germination.

Maize is a valuable raw material for feed and food production. Healthy seed germination is important for improving the yield and quality of maize. Seed aging occurs relatively fast in crops and it is a process that delays germination as well as reduces its rate and even causes total loss of seed viability. However, the physiological and transcriptional mechanisms that regulate maize seeds, especially aging seed germination remain unclear. Coronatine (COR) which is a phytotoxin produced by Pseudomonas syringae and a new type of plant growth regulator can effectively regulate plant growth and development, and regulate seed germination. In this study, the physiological and transcriptomic mechanisms of COR-induced maize seed germination under different aging degrees were analyzed. The results showed that 0.001-0.01μmol/L COR could promote the germination of aging maize seed and the growth of primary roots and shoots. COR treatment increased the content of gibberellins (GA3) and decreased the content of abscisic acid (ABA) in B73 seeds before germination. The result of RNA-seq analysis showed 497 differentially expressed genes in COR treatment compared with the control. Three genes associated with GA biosynthesis (ZmCPPS2, ZmD3, and ZmGA2ox2), and two genes associated with GA signaling transduction (ZmGID1 and ZmBHLH158) were up-regulated. Three genes negatively regulating GA signaling transduction (ZmGRAS48, ZmGRAS54, and Zm00001d033369) and two genes involved in ABA biosynthesis (ZmVP14 and ZmPCO14472) were down-regulated. The physiological test results also showed that the effects of GA and ABA on seed germination were similar to those of high and low-concentration COR, respectively, which indicated that the effect of COR on seed germination may be carried out through GA and ABA pathways. In addition, GO and KEGG analysis suggested that COR is also highly involved in antioxidant enzyme systems and secondary metabolite synthesis to regulate maize seed germination processes. These findings provide a valuable reference for further research on the mechanisms of maize seed germination.

ESTABLISHMENT OF AN EFFICIENT MICROPROPAGATION PROTOCOLS FOR THREE KENAF (HIBISCUS CANNABINUS L.) CULTIVARS

This study was aimed to establish an efficient micropropagation protocol for three popular kenaf (Hibiscus cannabinus L.) cultivars (V36, HF992 and KB6) using different types of plant growth regulators (PGR’s) on Murashige and Skoog medium (MS). The shoot tip, cotyledon and hypocotyl isolated from 2 weeks old seedlings were used as explants. MS medium fortified with different types and concentrations of cytokinins and auxin were evaluated for establishment callus formation, shoot multiplication and rooting. Among different PGR’s used, 5.0 mg/l 2iP + 0.1 mg/l NAA was the best concentration for direct shoot regeneration from cotyledon with shooting percentage of 55% in HF992 cultivar. In multiple shoot induction experiment, 1.0 mg/l TDZ + 0.1 mg/l NAA mg/l concentration has induced the highest (10.4) shoots/explant. Moreover, indirect shoot regeneration was established from callus which was induced from cotyledon, maximum callus induction percentage (88.75%) was recorded on 0.5 mg/l TDZ and 1.0 mg/l NAA in V36 variety. While, for shoot elongation and rooting, MS media half strength supplemented with 1.0 mg/l kinetin + 1.0 mg/l IBA was found to be an optimum concentration.

Prohexadione Calcium and Gibberellin Improve Osmoregulation, Antioxidant Response and Ion Homeostasis to Alleviate NaCl Stress in Rice Seedlings

Prohexadione calcium (EA) and gibberellin (GA) are two different types of plant growth regulators that have different effects on the regulation of plant development. The objective of this study was to evaluate the impacts of EA and GA on rice plant growth, development and morph-physiological traits in two rice varieties: ‘Huang Huazhan’ and ‘Guang Hong 3’. At the three-leaf seedling stage, the plants were treated with 50 mM NaCl 24 h after foliar application of EA (100 mg·L−1) and GA (1 mg·L−1). Data on morphological indexes, osmotic regulators and antioxidant activities were compared with the treatment of EA and GA on the 4th, 7th, 10th and 13th days after NaCl stress. Our data analysis showed that NaCl stress inhibited the leaf area growth of rice seedlings, altered the microstructure and disrupted the antioxidant system, ion uptake and transport balance. The significant increase in malondialdehyde (MDA) content and superoxide anion production rate (O2·¯) indicated that NaCl stress caused a severe oxidative stress response to rice seedlings. Treatment with EA and GA activated the antioxidant system under NaCl stress, significantly elevated superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities and suppressed the increase in MDA content and the O2·¯ production rate. Under NaCl stress, EA and GA treatments improved the osmoregulatory balance, significantly increased soluble protein and proline contents and maintained lower Na+/K+ levels. EA and GA treatments significantly increased the K+ and Ca2+ contents, thereby maintaining ionic balance, which was favorable for maintaining the growth of rice seedlings. In this study, moth plant growth regulators maintained the growth and development of rice seedlings under NaCl stress by inducing an increase in osmoregulation and antioxidant levels, reducing the degree of membrane damage and regulating the selective uptake of ions by rice seedlings. Current findings also clarified that foliar application of EA was more effective than GA in three-leaf seedlings by enhancing the morph-physiological and antioxidant parameters under NaCl stress.

Growth Responses of Okra (Abelmoschus esculentus L. Moench) to Selected Plant Growth Regulators

This study was conducted to evaluate the effects of two types of plant growth regulators (PGRs) which are gibberellins (GA3) and Paclobutrazol (PBZ) on the growth and photosynthetic pigment (chlorophyll) of Okra (Abelmoschus esculentus L. Moench) plants. Exogenous applications of GA3 and PBZ with different concentrations (i.e. 20, 40, 80 and 100 mg/L) were sprayed on two-week-old Okra plants under the nursery stage. The control plants were only treated with distilled water. The stem diameter (mm) of treated and control plants was measured weekly. At the end of the experimental period, data on growth characteristics such as plant height (cm), leaf area (cm2) and number of leaves were recorded. The estimation of chlorophyll was measured using the SPAD-502 Chlorophyll Meter. Results showed that the plant morphological characteristics of Okra plants were significantly affected by the application of GA3 and PBZ (P<0.0001). In addition, stem growth (expressed as stem cross-sectional area- mm2) of Okra plants was significantly increased with increasing GA3 concentrations. In contrast, applying PBZ reduced Okra plants' stem growth. This study highlighted the major effects of GA3 and PBZ on the growth of Okra plants when planted under tropical climate conditions.

Successful shoot tip grafting of cacao (Theobroma cacao L.) due to the application of plant growth regulators on various concentrations

Cacao plays an important role in the Indonesia economy. Therefore, its production and area expansion have to increase to achieve maximum cacao productivity by the quality and superior cacao clones. Shoot tip grafting is one of the propagation methods to obtain superior cacao plants by applying Plant Growth Regulators (PGRs). Research on the effect of several PGRs with various concentrations on cacao (Theobroma cacao L.) shoot tip grafting was conducted at the Integrated Innovation Farmer Group, Belubus, Sungai Talang Village, Guguak District, Lima Puluh Kota Regency, West Sumatra from February until June 2022. This study aimed to determine the interaction between PGR type and concentration on the grafting success and growth of cacao shoot tip grafted seedling. The research was designed by a Factorial Completely Randomized Design with three replications. The first factor was the type of PGR, i.e., synthetic PGR (BAP), young corn seed extract, shallot extract, and young coconut water. The second factor was the concentration of PGR, i.e., 0%, 25%, 50%, 75% and 100%. The results showed an interaction between PGRs with some concentrations on the number of shoots, shoot length, and leaf length on the grafted cacao seedling. The natural PGR from young coconut water at a concentration of 75% gave the best effect on the number of shoots (3.33 shoots) and shoot length (24.50 cm) of cacao seedling.

Effect of plant growth regulators on accumulation of radiocaesium in potato tubers

An important place among the problems of modern agriculture is occupied by the problems of rational use and protection of land and the ecologically dangerous state of the environment. The Zhytomyr region is one of the most affected by the accident at the Chernobyl nuclear power plant. A significant part of agricultural land has a density of contamination with cesium-137 up to 5 Ki/km2, which is 75 % of all contaminated land in the districts, about 20 % of agricultural land has a density of contamination from 5 to 15 Ki/km2, 5 % – above 15 Ki/km2. On lands with a higher density of pollution, it is necessary to apply a complex of agrochemical, agrotechnical and organizational measures to reduce the transfer of radionuclides from the soil to plants. Solving problems related to farming in radioactively contaminated territories occupies one of the leading places in the complex of measures to mitigate the consequences of the Chernobyl accident. The purpose of the research was to establish the effect of different doses and types of plant growth regulators on the productivity of potatoes, the level of radioactive contamination in the agro-ecological conditions of Polissia. Our research was carried out in the agro-ecological conditions of Polіssia LLC. Councilors of Ovrutsky district of Zhytomyr region. The transition of the radioactive isotope cesium-137 from the soil to the plants depends on the content of exchangeable potassium in the soil, the saturation of the soil-absorbing complex with bases, the reaction of the soil solution, the bonification of the soil, and the content of humus. When the agrochemical parameters of the soil improved, in particular when the content of exchangeable potassium in the soil increased from 2.3 mg/100 g of soil to 14.8 mg/100 g of soil, the specific activity of radiocesium in plants de-creased by 3.4 times. The results of our research show that the foliar treatment of potato plants with Biosil and Poteitin contributed to a decrease in the specific activity of tubers from 29.2 to 6.4–2.1 Bq/kg. It was established that foliar spraying of potato plants with Biosil and Poteitin contributed to the reduction of the coefficient of 137Cs transition to 0.03 and 0.01.

An Overview: Effect of Plant Growth Regulatory on Orchid Propagation through The Thin Cell Layer technique

Thin cell layer (TCL) is a micropropagation method using thin-sized explants. A TCL can be prepared from any explant source and the thichness of explant less than 5 mm. TCL is more efficient in producing total plantlet output than conventional in vitro methods. TCL have been applied to the in vitro culture of orchids, field, vegetable crops and medicinal plants The successful in vitro orchid propagation is influenced by many factors, such as plant genotype and media composition. Additions of plant growth regulator (PGR) in media culture is essential factor. The formation of complete plant depent on concentration and type of plant growth regulator. TCL explants require growth regulators to form an embryonic callus and zygotic embryos. Explant in medium without supplemented of growth regulators resulted in browning and failed to grow. The most commonly plant growth regulator in tissue culture are thidiazuron (TDZ), 6-benzylaminopurine (BAP) 2,4 dichlorophenoxyacetic acid (2,4-D), α-naphthaleneacetic acid (NAA), and meta-Topolin. Recently, microalgae can also be used as an alternative source of hormones to increase plant growth through in vitro culture techniques

Effect of Plant Growth Regulators for Improvement of the Quality and Shelf Life of Kinnow (Citrus nobilis x Citrus deliciosa): A Review

Plant growth regulator’s plays a very important role in Kinnow production. There are different type of PGR’s that includes GA3, NAA, CPPU and Ethyl which when applied on kinnow performs well and give good results such as high quality, yield and long shelf life of the fruit. Plant growth regulators (PGRs) are well known for having a significant impact on fruit retention. Plant growth regulators are hormones that are involved in physiological functions, developmental aspect and have an impact on cell development and growth. They are cellular communication tools known as chemical messengers Also known by the name "plant hormones”. Plant growth regulators enhance fruit set, minimize fruit drop, and correct a variety of physiological functions to improve quality and productivity by improving the physiology of fruits. Gibberellins and auxin are frequently used to reduce fruit drop and enhance fruit quality. The primary role of plant growth regulators in the creation of Kinnow mandarins is the main subject of this review.

Response of Auxins and Cytokinins on Citrus suhuiensis Adventitious Shoot Culture Initiation and Growth

Bacterial and viral diseases are the common problems hampering vast majority of citrus plant which resulted in the decrease of citrus trees development and production yield. While the usage of chemicals to eliminate internal pathogens is harmful to the ecosystem, plant tissue culture is another alternative to develop disease-free plants based on the defined physical and chemical conditions under aseptic environment. This study aimed to initiate Citrus suhuiensis (C. suhuiensis) adventitious shoot culture specifically in response towards different types of plant growth regulators (PGRs). The effect of explants and PGRs were evaluated on the shoot growth within 35 days. C. suhuiensis shoot cultures were induced from three different explants which are leaf, callus and seeds on the solid Murashige and Skoog (MS) medium containing different combinations of PGR which are auxins i.e. 1-naphthylacetic acid (NAA) or indole butyric acid (IBA) at 0.5 mg/L, respectively with cytokinins i.e. 6-benzylaminopurine (BAP) or kinetin (KN) at various concentrations (0.5 - 4.0 mg/L). Based on the results, the earliest shoot emergence from the cotyledon can be observed after 8th day of inoculation for PGRs combination of 0.5 mg/L IBA with 2.0 mg/L, 3.0 mg/L KN and 3.0 mg/L BAP, respectively. Meanwhile, based on the ANOVA analysis (p-value < 0.05), the most significant PGRs combination for the establishment of C. suhuiensis shoot culture is IBA and KN followed by the treatment of NAA and KN. The findings of this study can serve as a basis for future investigation of micropropagation of shoot culture and cultivation of C. suhuiensis plant.

Appropriate Condition for Cluster Buds Induction of <i>Cremastra appendiculata</i>

To screen for suitable conditions for cluster bud induction of Cremastra appendiculata . The aseptic germination protocorms of C. appendiculata  seeds were used as explant materials to explore the effects of different basic media, types of plant growth regulators, anti-browning agents and their concentrations on the induction of cluster buds of C. appendiculata . The results showed that: 1/4MS medium was the suitable basic medium for cluster buds growing; when the concentration of plant growth regulator TDZ was 2.0 mg/L and the concentration of IAA was 0.2 mg/L, the induction rates of cluster bud were higher which are 72.58% and 55.63% respectively; when the anti-browning agent was PVP and its concentration is 2 000 mg/L, the induction rate of cluster buds was higher which is 79.90%. The suitable conditions for C. appendiculata cluster buds induction are: 1/4MS + TDZ 2.0 mg/L+ IAA 0.1 mg/L+ PVP 2 000 mg/L, and the induction rate can reach 81.16%. This provided a basis for establishing a rapid propagation technology system of  C. appendiculata  and realizing its large-scale artificial cultivation.

Heavy Metals, Pesticide, Plasticizers Contamination and Risk Analysis of Drinking Water Quality in the Newly Developed Housing Societies of Gujranwala, Pakistan

The supply of clean drinking water is essential for a healthy life, but access to safe and healthy drinking water has become a key issue worldwide, especially in developing nations such as Pakistan. This research work focused on investigating the suitability of groundwater by measuring quality parameters, identification of pesticide pollutants, and health risk analysis in adults and children due to the consumption of groundwater in recently developed housing societies of the Gujranwala district, Punjab, Pakistan. Drinking water samples (n = 200) were collected from electric water pumps and analyzed by in situ testings following the Standard American Public Health Association (APHA) methods. Pesticides and plasticizers detection was carried out using gas chromatography-mass spectrometry (GC/MS). Results showed that the concentrations of dissolved Cr and Pb at more than 20% of sampling sites exceeded the allowable limit of the World Health Organization (WHO). However, the measured physico-chemical attributes and concentrations of Fe and Zn did not exceed their respective permissible limits. The most abundant pollutants detected were plasticizers (30); followed by herbicides (21); fungicides, acaricides, and insecticides (16); and various types of plant growth regulators (7). Differential patterns for the hazard quotient (HQ) and hazard indices (HI) were observed, of which were above the WHO limits. The decreasing order of the hazard quotient was Cl > Zn > Mg > Cr > Pb for both adults and children. In crux, the quality of water is poor for drinking purposes and the safety and well-being of residents in the recently developed housing societies of the study area may be at risk. Hence, it is important to implement a plan for water quality management, and the regular monitoring (periodic testing of qualitative and quantitative attributes) of the water quality to overcome health-related issues.

Somatic embryogenesis of the selected intergeneric hybrid between Phalaenopsis 2166 and Vanda ‘Saint Valentine’: Application of NAA and TDZ

Abstract. Dwiati M, Susanto AH, Budisantoso I. 2022. Somatic embryogenesis of the selected intergeneric hybrid between Phalaenopsis 2166 and Vanda' Saint Valentine': Application of NAA and TDZ. Nusantara Bioscience 14: 160-165. Intergeneric hybridization between Phalaenopsis 2166 and Vanda' Saint Valentine' has produced a hybrid seedling with several characters potentially developing into plant individuals with flowers of better performance. Therefore, identical clones of the selected hybrid should be developed into PLBs using an in-vitro culture technique employing somatic embryogenesis supported by the application of plant growth regulators. This study aims to unveil the effect of NAA and TDZ in stimulating the formation of identical clones of the selected intergeneric hybrid between Phalaenopsis 2166 and Vanda' Saint Valentine'. The experiment was arranged in a factorial Randomized Complete Block Design (RCBD) involving two factors, i.e., types of plant growth regulators and the levels of concentrations of each substance. It was found that the combination of NAA and TDZ significantly affected the growth of the identical clones. Furthermore, the combination of NAA 0.5 mgL-1 and TDZ 1.5 mgL-1 resulted in clones that potentially differentiate into PLBs. This finding indicates that NAA and TDZ should be applied appropriately to stimulate somatic embryogenesis in the intergeneric hybrid.

Trehalose Outperforms Chitosan, Humic Acid and Gamma-Aminobutyric Acid in Promoting the Growth of Field Maize.

Despite the fact that there are many distinct types of plant growth regulators (PGRs), the diverse ways in which they regulate plant development are rarely compared. In this study, four PGRs (trehalose, chitosan, humic acid and gamma-aminobutyric acid) were selected and sprayed folially, and plant samples were collected while maize was at vegetative leaf stages 6, 10, and 14 (V6, V10, and V14, respectively) to reveal the effects of different PGRs on photosynthesis, dry matter accumulation, oxidative stress, carbon and nitrogen metabolism, hormone levels, and gene expression of maize. Results showed that 100 mg/L PGRs did not induce oxidative damage or repair activities in maize. Trehalose significantly increased chlorophyll content at V6 and promoted dry matter (roots and shoots) accumulation at V6 and V10. The activities of carbon and nitrogen metabolizing enzymes were significantly enhanced by trehalose treatment, which promoted the accumulation of sucrose and soluble sugar, but did not affect the biosynthesis of auxin and gibberellin at V6. Changes in carbon and nitrogen metabolism enzymes are regulated by transcription of related synthetic genes. Lower starch content and higher sucrose content in trehalose-treated maize leaves are important biological characteristics. Further analysis revealed that the effect of trehalose on the metabolic activity of maize was a short-term promoting effect (0–12 days), while the effect on maize growth was a long-term cumulative effect (13–28 days). Overall, exogenous trehalose induced stronger carbon and nitrogen metabolic activity, higher photosynthetic capacity and more dry matter accumulation than chitosan, humic acid and gamma-aminobutyric acid.

Development of Designer Transcription Activator-Like Effector-Based Plant Growth Regulator for Higher Yield in Rice.

Recent studies have shown that reprogramming of gene expression in a genome can induce the production of proteins enabling yield increase. The transcription activator-like effectors (TALEs) from several species of bacterial Xanthomonas have been extensively studied, and a series of research tools, such as genome editing tool TALENs and gene expression activators, have been developed based on the specific protein–nucleic acid recognition and binding mechanisms of TALEs. In this proof-of-principle study, we designed and constructed a designer TALE (dTALE), designated as dTALE-NOG1, to specifically target the promoter of OsNOG1 gene in rice, and demonstrated that this dTALE can be used as a new type of plant growth regulator for better crop growth and harvest. In doing so, the dTALE-NOG1 was transferred into the non-pathogenic Xanthomonas oryzae pv. oryzae (Xoo) strain PH to generate a genetically engineered bacteria (GEB) strain called PH-dtNOG1. Functional verification showed that dTALE-NOG1 could significantly induce the expression of OsNOG1. By spraying cell suspension of PH-dtNOG1 on the rice plants during the tillering stage, the transcription level of OsNOG1 was highly enhanced, the grain number of rice plants was increased by more than 11.40%, and the grain yield per plant increased by more than 11.08%, demonstrating that the dTALE-NOG1 was highly effective in enhancing rice yield. This work provided a new strategy for manipulating agronomical traits by reprogramming gene expression in a crop genome.

Physiological Mechanism of Exogenous 5-Aminolevulinic Acid Improved the Tolerance of Chinese Cabbage (Brassica pekinensis L.) to Cadmium Stress

The 5-aminolevulinic acid (ALA), a new type of plant growth regulator, can relieve the toxicity of cadmium (Cd) to plants. However, its mechanism has not been thoroughly studied. In the study, the roles of ALA have been investigated in the tolerance of Chinese cabbage (Brassica pekinensis L.) seedlings to Cd stress. The results showed that Cd significantly reduced the biomass and the length of the primary root of seedlings but increased the malondialdehyde (MDA) and the hydrogen peroxide (H2O2) contents. These can be effectively mitigated through the application of ALA. The ALA can further induce the activities of antioxidant enzymes in the ascorbate-glutathione (AsA-GSH) cycle under Cd stress, which resulted in high levels of both GSH and AsA. Under ALA + Cd treatment, the seedlings showed a higher chlorophyll content and photosynthetic performance in comparison with Cd treatment alone. Microscopic analysis results confirmed that ALA can protect the cell structure of shoots and roots, i.e., stabilizing the morphological structure of chloroplasts in leaf mesophyll cells. The qRT-PCR results further reported that ALA downregulated the expressions of Cd absorption and transport-related genes in shoots (HMA2 and HMA4) and roots (IRT1, IRT2, Nramp1, and Nramp3), which resulted in the low Cd content in the shoots and roots of cabbage seedlings. Taken together, the exogenous application of ALA alleviates Cd stress through maintaining redox homeostasis, protecting the photosynthetic system, and regulating the expression of Cd transport-related genes in Chinese cabbage seedlings.

THE RESPONSES OF ROSELLE (Hibiscus sabdariffa L.) TO THE APPLICATION OF PLANT GROWTH REGULATORS IN DEVELOPING SEEDLESS FRUIT AND MAINTAINING ITS QUALITY

Seedless fruit is a fruit developed to possess no mature seeds. Today lifestyle, consumers and/or manufacturers prefer fruit without seeds as removing it is time-consuming and troublesome. Indeed, seedless fruits have better organoleptic attributes than seeded fruits. To produce seedless roselle and maintain its postharvest quality, various spray applications of synthetic and naturally occurring plant growth regulators were investigated. Roselle is perishable and non-climacteric fruit that is exposed to rapid postharvest physiological deterioration following harvest. Thus, producing seedless fruit may reduce time and labor costs during the removing seed process. The experimental treatments were arranged in randomized complete block design with different types of plant growth regulators and spray applications. The PGRs treatments at varying frequencies were sprayed on roselle flower buds at 35, 45, 55, and 65 days after transplanting (DAT). Among all PGRs treatments, the plant treated with 800 mg/L GA3 + seaweed extract (4 sprays) had developed seedless roselle fruit by exhibiting the smallest capsule diameter, capsule volume, and a low number of seeds. In a conclusion, the application of 800 mg/L GA3 + seaweed extract (4 sprays) was the effective concentration to produce seedless roselle fruit and maintain its postharvest quality.

VARIACIÓN SOMACLONAL EN PLANTAS DE Phalaenopsis sp. var. Dudú REGENERADAS POR EMBRIOGÉNESIS SOMÁTICA DIRECTA

<p><strong>Background</strong>: Nowadays, a growing demand for hybrids of <em>Phalaenopsis</em> sp. exists to satisfy this demand it is necessary to develop protocols for massive propagation that ensure high percentages of clonal regeneration, such as somatic embryogenesis. Besides, studying genetic variation within regenerated plants offers a greater understanding of the suitability of the micropropagation protocol in relation with genetic stability of the materials used. <strong>Objective</strong>: The present research work aimed to evaluate three concentrations of two types of plant growth regulators (RCV). 6-benzylaminopurine cytokinin (BA) (1.0, 2.0 y 3.0 mgL<sup>-1</sup>) in combination with three concentrations of 2,4-diclorofenoxiacetic acid (2,4-D) (3.0, 4.0, 5.0 mgL<sup>-1</sup>), for the induction of somatic embryos. In addition, the genetic stability of the regenerated plants was analyzed using molecular markers type RAPD (Random Amplified Polymorphic DNA). <strong>Methodology</strong>: The induction of somatic embryogenesis was induced from two leaf explants with different stages of develop from 15-20 cm in height <em>Phalaenopsis</em> sp. var. Dudú seedlings, cultivated <em>in vitro</em>; first leaf as mature explant (PH) and third leaf as young explant (TH). <strong>Results</strong>: The highest number of regenerated plants was 29.8 at 135 days after the start of the culture (ddic) with 2.0 and 5.0 mgL<sup>-1</sup> of BA and 2,4-D, respectively, using TH as explant. In the morphogenetic response of the regenerated explants, a correlation was observed between the age of the explant and the RCV concentration. Polymorphic bands were observed with the four primers used, indicating somaclonal variation in regenerated plants. <strong>Implications</strong>: The results obtained provide an alternative for regeneration, as well as offering a methodology to initiate genetic improvement programs in <em>Phalaenopsis</em> sp. var. Dudú. <strong>Conclusions</strong>: <em>In vitro</em> regeneration of <em>Phalaenopsis</em> sp. var. Dudú by somatic embryogenesis was achieved, as well as the analysis of the genetic integrity of the regenerated material. </p>

A Study on the Possible Mutagenicity of Different Types of Plant Growth Regulators

It is known that most chemicals, which have been increasingly used since ancient times, have carcinogenic and mutagenic effects. As an alternative to these chemicals, natural compounds, such as plant growth regulators (PGRs) have been used. However, are the PGRs used to obtain efficient plants in agriculture as harmless as it is thought today when it is essential to access natural foods in the food and agriculture sectors? Therefore, this study investigates the mutagenic activity of two plant growth regulators (Kinetin, Chlormequat chloride (CCC)) using the Ames/Salmonella short-time test system. Experiments were performed in the presence (+ S9) or absence (-S9) of metabolic activation enzymes using TA 98 and TA 100 strains of Salmonella typhimurium. 5 non-cytotoxic doses for each test substance were investigated. The results were evaluated by comparing them with spontaneous control plates. According to the results, a 2500 µg/plate dose of Kinetin was to be found mutagenic on the strain TA 98 in the presence and in the absence of S9 enzyme, and on the strain TA 100 in the absence of the S9 enzyme. The other substance CCC did not cause mutagenic effects on the bacterial strains.

Effects of Media and Plant Growth Regulators on Mini-Tuber Yield of Granola Cultivar of Potato in Aeroponics System

<p>Potato is a perennial plant (<em>Solanum tuberosum L</em>.) in the nightshade family, which is one of the most developed and competitive vegetable crops compared to other vegetables. Furthermore, its production could not meet the increasing demand, which led to very intensive research and development programs. This research aims to examine the effect of nutrients and growth regulators on the yield of mini-tuber in the aeroponic system and to determine the best type of nutrient, as well as the type and concentration of plant growth regulators to increase mini-tubers yield in an aeroponics system. This experiment has been carried out experimentally using a split-split plot design. The main plots were the types of nutrient media, which consisted of Grow More-modified nutrient and AB-Mix nutrient. The sub-plots were the types of plant growth regulator (PGR), which consisted of BAP and GA<sub>3</sub>, while the sub-sub-plot were the concentrations of PGR, which consisted of 0; 5; 10; 15; 20 and 25 µM. Each combination of treatments was repeated three times. The results showed that the use of media type, PGR and PGR concentration affected the formation and yield of Granola cultivar of potato mini-tubers. Knols grown in AB-Mix nutrient medium supplemented with 20 µM GA<sub>3</sub> resulted in the best mini-tuber formation, as shown by the average number of mini-tubers of 8.33, the total weight of mini-tubers of 21.38 g and the average mini-tuber diameter of 13.05 mm.</p>