Effect Of Cytokinins Research Articles

Effect of nano micronutrients and cytokinin on wheat (Triticum aestivum L.) in different irrigation conditions

Different strategies are required to mitigate drought stress in plants. In order to effect of nano micronutrient and cytokinin on wheat under different irrigation regimes, the experiment was performed in Karaj city, Iran. The experimental factors included irrigation regimes at three levels [I1: normal irrigation, I2: normal irrigation from planting date to pollination stage, and irrigation at 60% available moisture discharge afterward, I3: normal irrigation from planting date to pollination stage, then holding cutoff irrigation], was considered as the main plots. Nano microelements at five levels: [control, zinc, iron, selenium and a combination of three elements (zinc + iron + selenium)], and cytokinin at four levels [control, flowering stage, milking development, flowering stage + milking development], were placed as the subplots. The results indicated that irrigation, cytokinin and nano micronutrients were significant in the traits of this study. The interaction effects of the treatments were not significant. Drought significantly decreased grain yield and biomass. In irrigation treatments, I1 increased grain yield (70.8%), chlorophyll index (80.44%), and superoxide dismutase (57.71%) compared to I3. In nano micronutrients, the combination of three elements promoted grain yield (75%), chlorophyll index (87.67%), and superoxide dismutase (68.76%). Cytokinin plays a significant role in wheat yield promotion. In cytokinin spraying, the flowering + milking treatment raised grain yield (71.56%), chlorophyll index (62.97%), and superoxide dismutase (41.13%). The present study may thus help to increase wheat yield with normal irrigation, the interaction of microelements (zinc + iron + selenium) and cytokinin in flowering + milking stages and can suggest improving wheat yield.

Development of effective micropropagation protocols for endangered Gentiana lutea and Gentiana boissieri (endemic to Türkiye)

Abstract Gentiana spp. are ornamental as well as valuable medicinal plants. This research was conducted to investigate the effects of different cytokinin and auxin treatments on shoot propagation and rooting of both G. lutea and G. boissieri, and to establish the most appropriate micropropagation protocols for these species. For this purpose, MS media containing benzyl adenine (BA) (1, 2, 3, and 4 mg/l), zeatin (0.5, 1, 2, and 3 mg/l), and kinetin (0.5, 1, 2, and 3 mg/l) were used for shoot propagation, and the optimal cytokine applications were determined by examining shoot number per explant (SN/E) and shoot length (SL). To determine rooting ability, shoots were transferred to MS media containing indole acetic acid (IAA), indole butyric acid (IBA), and naphthalene acetic acid (NAA) at different concentrations (1, 2, 3, and 4 mg/l). The optimum auxin applications for root and plant development were determined by examining the rooting percentage (%, RP), root number per shoot (RN /S), root length (RL), shoot length (SL), and plant fresh weight (FW). As a result of the study, it was found that the media containing 3 mg/l and 2 mg/l BA were the most suitable shoot propagation media for G. lutea and G. boissieri, respectively. The media containing 4 mg/l IBA and 1 mg/l AgNO3 gave the highest rooting and growth parameters for G. lutea, while G. boissieri had the best rooting and growth values in media supplemented with 2 mg/l NAA. In addition, G. boissieri was found to be superior to G. lutea in both shoot propagation and rooting.

Beyond expectations: the development and biological activity of cytokinin oxidase/dehydrogenase inhibitors.

Cytokinins are one of the main groups of plant hormones that regulate growth and development of plants. Cytokinin oxidase/dehydrogenase (CKX) is an enzyme that rapidly and irreversibly degrades cytokinins and thus directly affects their concentration and physiological effect. Genetically modified plants with reduced CKX activity in the shoot, i.e. with a higher concentration of cytokinins, showed e.g. increased tolerance to drought stress, formed larger inflorescences and had higher grain yield. For these reasons, chemical compounds capable of inhibiting the CKX activity (CKX inhibitors) were sought. First, they were identified among strong synthetic cytokinins, but their inhibitory activity was low. The trend has been to develop potent CKX inhibitors with minimal intrinsic cytokinin activity in the hope of avoiding the negative effect of cytokinins on root growth. Cloning CKX, production of key recombinant enzymes from Arabidopsis (AtCKX2) and maize (ZmCKX1 and ZmCKX4a), development of screening bioassays and progress in X-ray crystallography and synthetic organic chemistry led to extensive progress in the development of these compounds. Currently, the most suitable CKX inhibitors are seeking their application in research and the commercial sphere in two main areas - plant tissue cultures and agriculture. The key milestones that preceded it are summarized in this review.

Phylogenomic analysis of glutamine synthetase gene family in Helianthus annuus L.

Glutamine synthetase is one of the predominant enzymes in nitrogen metabolism. In developing leaves, glutamine is mainly produced in chloroplasts by the activity of the GS2 isoenzyme. It catalyzes glutamine synthesis from glutamate and ammonia in an ATP-dependent reaction. The genes encoding glutamine synthetase play a crucial role in ammonia and glutamate detoxification, acid-base homeostasis, cell signaling, and cell proliferation. The gene family responsible for producing glutamine synthetase has been previously documented in model plants like Arabidopsis. Nevertheless, there has been no exploration into its existence and attributes in oilseed crops like sunflower (Helianthus annuus L.). This study thoroughly analyzes, gene structure, conserved motifs, chromosomal location, phylogenetic relationships, and expression patterns to identify the glutamine synthetase genes in H. annuus. Our findings unveiled 19 genes encoding glutamine synthetase within the H. annuus genome. These genes were distributed across 11 chromosomes of H. annuus. Furthermore, we examined the expression patterns of all the HaGS genes using RNA-seq datasets, specifically focusing on their response to biotic and abiotic stress conditions. Under biotic stress, H. annuus expresses genes for mycorrhizal fungi named Rhizoglomus irregulare at four days post inflorescence (dpi) and 16 dpi. Under abiotic stress, the effect of drought and hormones was investigated. In drought, one gene, HaGS6D, showed the highest expression in the leaf. Meanwhile, in roots, gene HaGS7B showed the highest expression. Under hormonal stress, the effects of auxin, brassinosteroid, and cytokinin were studied on the leaf. For auxin, the gene HaGS7C showed the highest expression. For brassinosteroid, the gene HaGS7D showed the highest expression; for cytokinin, the gene HaGS6E showed the highest expression. Thus, these findings can significantly contribute to our understanding of the arrangement of glutamine synthetase genes in H. annuus and offer valuable insights for developing of drought-resistant cultivars of this species.

The effect of different cytokinin and auxin source on micropropagation of Kalanchoe blossfeldiana

Micropropagation is widely used for vegetative propagation of many different ornamental and medicinal plant species under aseptic conditions. This technology has widespread practical applications irrespective of seasonal and time-space constraints. The present study aimed to design in vitro propagation using 1 8 different combinations of BAP, NAA, TDZ, and GA3 supplemented with commercial tea sugar at 30 g l-1 for micropropagation using leaf segments close to petiole of Kalanchoe blossfeldiana as explants and to find its efficiency for viable cultures. The results showed clear discrimination between regeneration on TDZ and BAP-supplemented regeneration cultures. Thus, both BAP-NAA and TDZ-NAA combinations were found suitable for micropropagation. the source medium affected the shoot regeneration and the rooting ability, irrespective of the culture of any shoot regeneration medium. These plantlets were rooted in 0.01-0.05 mg l-1 IBA. The study showed successful rooting under in vitro conditions using 1 ½ or 1×MS medium with 0.5 mg L-1 IBA. These rooted plantlets were then transferred to MS medium with 0.2 mg L-1 gibberellic acid and without BAP or with 0.1, 0.2, 0.5 mg l-1 TDZ and 0.1 mg l-1 NAA or without 0.1 mg L-1 NAA for adaptation. The results of the study are of great importance for K. blossfeldiana plant breeding studies and growers.

Growth Promotion and In vitro Seed Germination of Lycium barbarum L. (Red Goji) Using Different Types of Cytokinins.

Lycium barbarum L., commonly known as red goji berry, is a widely recognized plant-based medicinal herb with nutritional and therapeutic properties. In this study, the effects of various cytokinins on the germination of L. barbarum seeds and the growth of seedlings were investigated under in vitro conditions. The berries were first surface sterilized and dissected, and the seeds were then cultured on Murashige and Skoog (MS) medium supplemented with different concentrations (0.5, 1.0, and 1.5 mg/L) of 6-benzylaminopurine (BAP), thidiazuron (TDZ), and kinetin (KIN) for 10 weeks at 25±2ºC with a photoperiod of 16 hours and a light intensity of 1000 lux. Upon observation after 10 weeks of culture, all cytokinin-treated cultures produced 100% seed germination as early as 7 days. KIN at 0.5 mg/L produced plantlets with the greatest height (8.40 ± 0.97 cm) with extensive rooting and the greatest total chlorophyll production. Besides, KIN at 1.5 mg/L resulted in the highest number of leaves per plantlet (6.90 ± 0.72), while 1.0 mg/L of TDZ led to the greatest biomass, i.e., fresh weight (FW) of 0.328 ± 0.05 gram and dry weight (DW) of 0.023 ± 0.003 gram. All cytokinins used in this experiment (BAP, TDZ, and KIN) promoted different in vitro growth promotion responses in L. barbarum. The effects of different types and concentrations of cytokinin on the height of plantlets, number of leaves per plantlet, fresh and dry weight, the extent of rooting, and the chlorophyll content were demonstrated to be statistically significant. This study provides valuable insights into optimizing in vitro cultivation techniques for goji berry propagation, which could contribute to developing superior cultivars and increased production of this superfruit in the future. For future perspectives, extended research in elucidating the underlying mechanism associated with cytokinin supplementation is imperative to understanding the roles of cytokinins and optimizing their effects on plant growth promotion.

The effect of UV-C radiation and cytokinin on pea plants

Aim. The effect of ultraviolet C (UV-C) radiation and cytokinin benzylaminopurine (BAP) on the growth and content of photosynthetic pigments in leaves of pea plants (Pisum sativum L.) was studied. Methods. Pea plants cultivar Aronis were irradiated by UV-C at a dose of 15 kJ/m2 with a power of 7 W/m2. Part of the non-irradiated plants was treated with BAP, part of the plants was treated with BAP one day before irradiation and part of plants were treated with BAP in one day after UV-C irradiation. Length and mass of plant shoots and roots were measured during the experiment. Content of photosynthetic pigments in leaves were determined during all time the experiment. Results. It was shown that pea plants growth delayed content of carotenoids in leaves reduced after the UV-C radiation of pea plants. Treatment of plants with BAP after the end of the UV-C radiation accelerated the restoration of photosynthetic pigments content. Conclusions. It was shown that UV-C radiation of pea plants by dose of 15 kJ/m2 caused inhibition of growth, decreasing photosynthetic pigments content in leaves. The BAP treatment after radiation stimulated the restoration of photosynthetic pigments content in the leaves.

Effects of LED lights and cytokinin on the phytotreatment of simulated swine wastewater by Azolla spp.: Pollutant removal and biomass valorization

Phytoremediation is an eco-friendly and affordable option for tackling wastewater pollutants. The study focused on how light-emitting diodes (LED) light exposure, measured by intensity and duration (photoperiod), along with cytokinin, impacts Azolla microphylla's simulated swine wastewater treatment performance and biomass production. Under optimal treatment conditions, high removals of COD (89.2 % to 90.8 %), N-NH4+ (72.6 % to 91.2 %), N-NO3- (84.4 % to 88.6 %), Cu (75.4 % to 86.4 %), sulfamethoxazole (77.0 % to 79.0 %), P-PO43- (54.1 % to 59.9 %) and DOC (67.4 % to 71.3 %) while Zn presented a more moderate reduction (2.0 % to 9.7 %). Biomass productivity reached up to 34.8 t ha-1 yr-1. Protein production accounted for 23 % to 27 % of dry weight, while lipids ranged from 20 % to 34 % of dry biomass. Carbohydrate content varied from 8 % to 28 % of fresh weight. Higher light intensities, with both high or low values of photoperiods, and low concentrations of cytokinin were identified as optimal conditions for removal of almost all pollutants. However, pollutant removal was impacted differently by LED light and cytokinin concentration. In treatment conditions with the shortest photoperiods (8 h), the lowest residual Cu and Zn concentrations, whereas with longer photoperiods (24 h), the lowest residual concentrations of N-NH4+ and P-PO43- concentrations were recorded. On the other hand, SMX was the only parameter in which cytokinin had a clear influence on its removal, with the lowest residual concentration observed under 8-hour photoperiods combined with the lowest tested cytokinin concentrations (0.3 mg L-1). For residual COD and N-NO3-, no discernible pattern was evident for any of the analyzed factors. Therefore, the study demonstrates the potential for treating simulated swine wastewater using Azolla microphylla, aligned with its ability to produce biomass rich in high-value compounds.

RhMYC2 controls petal size through synergistic regulation of jasmonic acid and cytokinin signaling in rose.

Petal size is determined by cell division and cell expansion. Jasmonic acid (JA) has been reported to be associated with floral development, but its regulatory mechanism affecting petal size remains unclear. Here, we reveal the vital role of JA in regulating petal size and the duration of the cell division phase via the key JA signaling component RhMYC2. We show that RhMYC2 expression is induced by exogenous treatment with methyl jasmonate and decreases from stage 0 to stage 2 of flower organ development, corresponding to the cell division phase. Furthermore, silencing RhMYC2 shortened the duration of the cell division phase, ultimately accelerating flowering opening and resulting in smaller petals. In addition, we determined that RhMYC2 controls cytokinin homeostasis in rose petals by directly activating the expression of the cytokinin biosynthetic gene LONELY GUY3 (RhLOG3) and repressing that of the cytokinin catabolism gene CYTOKININ OXIDASE/DEHYDROGENASE6 (RhCKX6). Silencing RhLOG3 shortened the duration of the cell division period and produced smaller petals, similar to RhMYC2 silencing. Our results underscore the synergistic effects of JA and cytokinin in regulating floral development, especially for petal size in roses.

Integrative analysis of transcriptome and phytohormones reveals new genes network involved in shoot apical meristem development in maize under blue and red light

Blue and red light play a significant role in regulating transcriptional expression, phytohormone levels, and gene signal network reconstruction in the shoot apical meristem. To further elucidate the effects of red and blue light on transcriptional characteristics and phytohormone expression, and to explore signaling pathways and novel genes, we conducted comparative experiments under different light quality treatments. The results are as follows: a total of 22,327 genes were found to be effectively expressed, with a considerable number of alternative splicing events occurring concurrently. Furthermore, 1063 differentially expressed genes were identified, primarily associated with transcriptional variations resulting from the transition from blue light to red light. These differentially expressed genes are predominantly involved in KEGG annotations related to photosynthesis, DNA replication and carbon metabolism. The findings from targeted metabolism analysis reveal significant variations in 45 phytohormones, including ABA, auxin, CK, ETH, GA, JA, and SA. Correlation analysis between transcription and metabolism further indicates that IAA.Glc, IAA.Glu, TRP, mT9G, and GA53 show the strongest correlation with differentially expressed genes, with genes ssu1, ssu2, pep1, me3, and hsp90 displaying a significant relationship. Additionally, in the protein–protein interaction network, three novel genes (LOC100286132, LOC100510780, and LOC103653934) were identified as significant responding to the regulation of blue and red light. Following protein function analysis, the proteins were provisionally identified as ubiquitin conjugating enzyme-like, OXIDATIVE STRESS 3LIKE 2-like, and Ribosomal L 18p/L5e, respectively. Conclusively, it is depicted that the most significant impact of transitions between red light, blue light, and two light qualities lies in the transcriptional process of shot apical meristem of the C4 plant maize. This process is intricately linked to nitrogen availability, carbon dioxide assimilation capacity, and the stimulatory effects of auxin, cytokinin, and gibberellin. The expression of the putative L 18/L5e in blue and BTR light conditions may enhance transcript and synthesis capabilities of ribosome.

Shoot Induction of Dendrobium lasianthera J.J.Smith with Several Types of Cytokinins through In Vitro Culture

Dendrobium lasianthera (Orchidaceae) is one of the potential plants as ornamental plants because it has beautiful and long-lasting flowers. Propagation of orchid plants through in vitro culture technique has been widely done to meet market demand. One of the supporting factors in plant propagation through in vitro culture techniques is growth regulators. Cytokinin is one of the growth regulators commonly used in plant propagation, including orchids. The study aims to determine the effect of several cytokinins and find the best type for shoot induction of Dendrobium lasianthera. The method used a Completely Randomized Design (CRD) with 4 treatments and 6 replications with several types of cytokinis (control; BAP 1.2 mg/L, Kinetin 2 mg/L, and Thidiazuron 1 mg/L) in Murashige & Skoog (MS) media. The results showed that several cytokinins significantly affected the number of shoots, time of shoot appearance, and shoot length of D. lasianthera. Thidiazuron was the best cytokinin for in vitro shoot induction of D. lasianthera

Effect of Gibberellic Acid and Cytokinin on Growth, Quality and Yield of French Bean (Phaseolus vulgaris L.) cv. Ellora No. 11

The experiment was conducted during Rabi season November – March, 2022-2023 at the Vegetable Research Farm, Department of Horticulture, Naini Agricultural Institute, Sam Higginbottom University of Agriculture, Technology & Sciences, and Prayagraj (UP). The experiment was laid out in Randomized Block Design with 10 treatments and 3 replication to study the “Effect of GA3 and Cytokinin on growth, quality and yield of French bean (Phaseolus vulgaris L.) cv. Ellora No 11.” The treatments which areT0: Control, T1:GA3@200ppm, T2: GA3@400ppm, T3:GA3@600ppm, T4:GA3@800ppm, T5:GA3@1000ppm, T6Cytokinin@250ppm, T7Cytokinin@500ppm, T8Cytokinin@750ppm, T9Cytokinin@1000ppm. The growth regulators were sprayed at 10 D.A.S in French bean. from the above experiment finding it is conclude that all the character viz., growth parameter, earliness parameter yield parameter, qualitative parameters varied significantly. Further, The result showed that the minimum days to first flowering(42.33DAS), first picking (63.33DAS) and days to 50% flowering(53.67 DAS) while the maximum plant height(52.07cm), no. of branches(13.57), no. of leaves(214.93), number of pod per plant(21.67),pod length(16.50), pod girth(2.63cm) 1 pod weight(5.70g), yield per ha(12.35t/ha), total soluble solids (6.37°BRIX), protein (1.52%), fiber (3.89%), ascorbic acid (11.77mg)and BC ratio (3.1) was found maximum in T1:GA3@200ppm

Effect of Auxin and Cytokinin on Orchid Subculture Resulting from Coelogyne Crosses

<p>The black orchid or Coelogyne is one of the native orchids of Kalimantan, widely cultivated in Indonesia. Several species of Coelogyne orchids have been crossed to obtain new superior-quality plants. Modifying the media, such as giving PGR, is necessary for good plant multiplication results. This research was conducted by changing MS growing media with ZPT BA and NAA. This experiment aimed to determine the effect of ZPT BA and NAA on the growth of orchid subcultures from a cross between<em> Coelogyne pandhurata </em>and<em> Coelogyne rumphii</em>. The study used a completely randomized design (RAL) with 2 factors, namely ZPT BA and NAA, each having a concentration of 0 ppm, 0.2 ppm; 0.4 ppm, and 0.6 ppm with 16 treatment combinations and 4 replications. They were implemented at the Laboratory Plant Physiology and Biotechnology, Faculty of Agriculture, UNS Surakarta, from November 2020 to March 2021. The variables observed included the number of shoots, plant length, plant weight, number of leaves, number of roots, root length, when roots appeared, and when shoots appeared. The results showed that BA 0.6 ppm gives the best output on the growth of the number of shoots, and NAA concentration of 0,2 ppm gives the best results on the variable number of roots. The combination of BA 0.6 ppm and NAA 0.2 ppm gave the best results on plant weight growth.</p>

Harnessing the potential of transverse thin cell layer culture for high-frequency micropropagation of Thai ginseng (Kaempferia parviflora Wall. Ex Baker)

In vitro plant propagation techniques play an important role in modern agriculture and horticulture, offering efficient methods for the accelerated multiplication of high-value plant species. Thin cell layer (TCL) culture technique has emerged as a promising approach for large-scale in vitro plantlets production. This study explores the potential of TCL culture as a cutting-edge strategy to enhance the efficiency of multiple shoots formation in Kaempferia parviflora. An attempt was also made to look into the synergistic effects of cytokinin and auxin [6-benzyladenine (BA) - indole-3-acetic acid (IAA)] during micropropagation. Shoot tip explants (from rhizome sprouts) were cultured onto Murashige and Skoog (MS) medium enriched with BA (2.0–8.0 mg/L) and IAA (0.2–0.8 mg/L) in combination where the highest shoot number (7.3 shoots/explant) and length (5.9 cm) was obtained in 8.0 mg/L BA and 0.8 mg/L IAA. Subsequently, the transverse thin cell layer (tTCL) culture system was successfully utilized whereby the shoot tip explants were individually sliced from tips at the meristem and cultured onto MS medium supplemented with BA (2.0–8.0 mg/L) and IAA (0.2–0.8 mg/L) in combination. The regenerated tTCLs exhibited the highest shoot multiplication (9.3 shoots/tTCL; 28 shoots/shoot tip) and length (5.3 cm) in 4.0 mg/L BA + 0.8 mg/L IAA, thus significantly increased number of plantlets were obtained from tTCL culture (953.0 plantlets) compared to shoot tip culture (527.7 plantlets) after six sub-culture cycles. The tTCL regenerants were successfully acclimatized (with 90% survival) and displayed active growth. Genetic fidelity assessment via inter-simple sequence repeats, conserved DNA-derived polymorphism, directed amplification of minisatellite-region DNA, and start codon targeted polymorphism marker systems suggested that a very low level (5.8%; 148 out of 2572 scorable bands) of polymorphism was detected whereas the ploidy level remained unchanged, confirmed by flow cytometry analysis. The implementation of tTCL culture, coupled with a controlled sub-culture regimen, holds significant potential for the efficient commercial-scale production of K. parviflora.

Effect of light and cytokinin on growth and curculin gene expression of Curculigo latifolia on in vitro culture.

Despite being valuable for producing a natural sweetener Curculin, Curculigo latifolia has a low growth and difficult to domestificate. So, to solve this problem, propagation on in vitro culture will be an alternative method to propagated this spesies under different cytokinins and light condition. Cytokinins and light has major role in organogenesis, growth and gene expression of many species. Thus, in this study, we aimed to improve the Curculigo latifolia growth on in vitro condition and expression of curculin gene by combining cytokinins addition and different light exposure. Four weeks seedlings were sub-cultured into medium (MS free hormone) containing 3 mg/L benzyladenine (BA) and various concentrations of meta-Topolin (mT) including 0.1 mg/L, 0.5 mg/L, and 5 mg/L. The cultures then incubated under different light types (red, blue, white LED lights and white fluorescence light) with 16-h light/ 18-h dark photoperiod for 14 weeks at 25 ± 2°C. Several parameters, including plant height, leaf number, chlorophyll contents, stomatal structure, and density and curculin expression, were observed every week. Unexpectedly, our results showed that C. latifolia growth displayed significant improvement when it was treated under white LED light without any additional cytokinins. In sum, white LED light further improves plantlets phenotype, such as plant height, leaf number, chlorophyll production, and stomatal number and structure, whereas, red LED light lead to a decreased phenotypes but increase the curculin gene expression.

Effect of anti-ethylene and cytokinin biostimulants on flowering and yield of Sweetpotato (Ipomoea batatas L.)

Breeding is needed to enhance the poor agronomic and qualitative attributes of the majority of sweetpotato cultivars grown in Nigeria. Even though the majority of cultivars don't often flower, the flowers are essential for genetic advancements. This study aimed to assess the effect of anti-ethylene (Silver-thiosulphate) and cytokinin (6-benzyladenine) biostimulants for induction of flowering and yield, to encourage early flowering of delayed sweetpotato genotype, and to ascertain the ideal concentration of growth regulators for sweetpotato flowering induction. A randomized complete block design with three replications was fitted with a 3x3x2 factorial arrangement. The first factor consisted of three different concentrations of two plant growth regulators (PGR): silver thiosulphate (STS) and 6-benzyladenine (BA) (0, 50, and 100 ppm). Three types of sweet potatoes (Umuspo3, Buttermilk, and Tis87) constituted the second factor. After planting, the BA and STS were administered three weeks later. The sweet potato varieties sprayed with STS and BA displayed morphological and physiological challenges, such as stem drooping (Temporal) (Page 1A), which recovered in 24 hours, root swelling, stem splitting, bud and flower production, vine branching, and elongation (Plate 1B). Varieties sprayed with high concentrations of STS (100 ppm) displayed significant morphological and physiological abnormalities, while those sprayed with BA displayed a significant increase in all growth metrics. However, two of the varieties Umuspo3 and Tis87 that were sprayed with STS and BA began buds and set flowers within two weeks after the treatment, whereas the plants that were not sprayed did not flower at all. The results of the interactions showed that the combination of benzyladenine + Umuspo3 at 100% (100T1V1) was superior for yield, whereas the combination of silver thiosulphate + Umuspo3 at 100% (100T2V1) was superior for the total number of flowers/plant. The vegetative growth parameters and the flowering characteristic exhibited a substantial positive connection (P<0.05), however the correlation between the vegetative growth traits and the yield traits was negative. As a result, the higher dosage of BA and STS (100 ppm) that was employed in this experiment is most likely quite near to the ideal concentration for sweet potato flower induction. Despite not being the ideal concentration, sweet potatoes can currently be induced to flower at this level, enabling the start of breeding programs for the crop.

Cytokinin and indole-3-acetic acid crosstalk is indispensable for silicon mediated chromium stress tolerance in roots of wheat seedlings

The rising heavy metal contamination of soils imposes toxic impacts on plants as well as other life forms. One such highly toxic and carcinogenic heavy metal is hexavalent chromium [Cr(VI)] that has been reported to prominently retard the plant growth. The present study investigated the potential of silicon (Si, 10 µM) to alleviate the toxicity of Cr(VI) (25 µM) on roots of wheat (Triticum aestivum L.) seedlings. Application of Si to Cr(VI)-stressed wheat seedlings improved their overall growth parameters. This study also reveals the involvement of two phytohormones, namely auxin and cytokinin and their crosstalk in Si-mediated mitigation of the toxic impacts of Cr(VI) in wheat seedlings. The application of cytokinin alone to wheat seedlings under Cr(VI) stress reduced the intensity of toxic effects of Cr(VI). In combination with Si, cytokinin application to Cr(VI)-stressed wheat seedlings significantly minimized the decrease induced by Cr(VI) in different parameters such as root-shoot length (10.8% and 13%, respectively), root-shoot fresh mass (11.3% and 10.1%, respectively), and total chlorophyll and carotenoids content (13.4% and 6.8%, respectively) with respect to the control. This treatment also maintained the regulation of proline metabolism (proline content, and P5CS and PDH activities), ascorbate-glutathione (AsA-GSH) cycle and nutrient homeostasis. The protective effect of Si and cytokinin against Cr(VI) stress was minimized upon supplementation of an inhibitor of polar auxin transport- 2,3,5-triiodobenzoic acid (TIBA) which suggested a potential involvement of auxin in Si and cytokinin-mediated mitigation of Cr(VI) toxicity. The exogenous addition of a natural auxin – indole-3-acetic acid (IAA) confirmed auxin is an active member of a signaling cascade along with cytokinin that aids in Si-mediated Cr(VI) toxicity alleviation as IAA application reversed the negative impacts of TIBA on wheat roots treated with Cr(VI), cytokinin and Si. The results of this research are also confirmed by the gene expression analysis conducted for nutrient transporters (Lsi1, CCaMK, MHX, SULT1 and ZIP1) and enzymes involved in the AsA-GSH cycle (APX, GR, DHAR and MDHAR). The overall results of this research indicate towards possible induction of a crosstalk between cytokinin and IAA upon Si supplementation which in turn stimulates physiological, biochemical and molecular changes to exhibit protective effects against Cr(VI) stress. Further, the information obtained suggests probable employment of Si, cytokinin and IAA alone or combined in agriculture to maintain plant productivity under Cr(VI) stress and data regarding expression of key genes can be used to develop new crop varieties with enhanced resistance against Cr(VI) stress together with its reduced load in seedlings.

The Role of Cytokinins during the Development of Strawberry Flowers and Receptacles.

Cytokinins play a relevant role in flower and fruit development and plant yield. Strawberry fruits have a high commercial value, although what is known as the "fruit" is not a "true" botanical fruit because it develops from a non-reproductive organ (receptacle) on which the true botanical fruits (achenes) are found. Given cytokinins' roles in botanical fruits, it is important to understand their participation in the development of a non-botanical or accessory "fruit". Therefore, in this work, the role of cytokinin in strawberry flowers and fruits was investigated by identifying and exploring the expression of homologous genes for different families that participate in the pathway, through publicly available genomic and expression data analyses. Next, trans-zeatin content in developing flowers and receptacles was determined. A high concentration was observed in flower buds and at anthesis and decreased as the fruit approached maturity. Moreover, the spatio-temporal expression pattern of selected CKX genes was evaluated and detected in receptacles at pre-anthesis stages. The results point to an important role and effect of cytokinins in flower and receptacle development, which is valuable both from a biological point of view and to improve yield and the quality of this fruit.

The Accumulation of Volatile Compounds and the Change in the Morphology of the Leaf Wax Cover Accompanied the "Anti-Aging" Effect in Anethum graveolens L. Plants Sprayed with 6-Benzylaminopurine.

Essential oils (EOs) are of commercial importance for medicine, food, cosmetics, the perfume industry, and agriculture. In plants, EOs, like the wax cover, serve as protection against abiotic stresses, such as high temperatures and water deficiency. The use of spraying with exogenous hormones of aromatic plants affects the accumulation and composition of volatile compounds, as well as tolerance to abiotic stress. As a result of cytokinin treatment with 6-BAP (6-benzylaminopurine) (200 mg L-l) of Anetum graveolens L. "Uzory" and "Rusich" varieties, several responses to its action were revealed: a change in the division of leaf blades, inhibition of flowering, an increase in the content of EO and its main components α-phellandrene and p-cymene in leaves, and limonene in umbels and fruits. It was revealed that the increased accumulation of EO in dill leaves was longer with sufficient moisture. In contrast, under conditions of heat and water deficiency, the effect of 6-BAP treatment on accumulations of the EO in leaves was short-lived and did not appear on umbels and fruits. The study of the cytokinin effect on a fine structure of a wax cover on the adaxial side of leaves by scanning electron microscopy revealed a change in its elements (from amorphous layers with scales to thin tubules), which probably increased the sensitivity of leaves to water deficiency and, consequently, led to a decrease in the biosynthetic activity of leaf tissue. Thus, 6-BAP had an impact on the adaptive properties of dill plants, prolonging the "youth" of vegetative organs and the ability to EO biosynthesis under conditions of sufficient moisture.

Effect of Auxin and Cytokinin on Grafting and Growth of Sapling of Guava (Psidium guajava L.)

The experiment was conducted to study the effect of auxin and cytokinin on grafting and growth of sapling of guava (Psidium guajava L.) at department of Horticulture, College of Agriculture, ummedganj, KOTA, KVK Modal nursery Agriculture university Kota during the year of 2020-21.In the investigation, L-49 cultivar of guava (Psidium guajava L.) was selected as mother plant for obtaining scion bud. The foliar spray of NAA and BA (50 and 25 ppm each) either on rootstock or/and scion branch was applied 10 days prior to grafting. The most responsive treatments was foliar spray on rootstocks with BA at 25 ppm concentration. Rootstocks treated with BA (25 ppm) resulted in length of scion shoot after grafting (16.63 cm), diameter of sprouted scion (2.80 cm), diameter of rootstocks (3.41 cm), number of leaves (20.83), leaf area (24.76 cm2), number of lateral shoot (7.89) as compared to others treatments.