Kinetin Treatment Research Articles

Micropropagation of three ginger cultivars and the subsequent growth and rhizome yield assessment and phytochemical composition analysis

Farmers have turned to biotechnology techniques to produce ginger, due to disease issues. Micropropagation is a proven and effective means for mass production of disease-free plants. Our research focused on ginger cultivar specific reactions (from culture initiation to rhizome harvest) to plant growth regulators (PGRs) to determine if plant response to PGRs is cultivar specific. Ginger (Zingiber officinale Rosc.) cultivars studied were: Chinese White (CW), Hawaii Yellow (HY), and Khing Yai (KY) under benzylaminopurine (BA) versus kinetin (KT) treatments using MS basal medium to micropropagate ginger seedlings and subsequent growth and yield performance and phytochemical composition analysis. In vitro culture data were collected every month for number of buds and shoots (and shoot length) produced per initiating bud and shoot growth. Mature seedlings were subsequently transplanted in a greenhouse with a randomized complete block design (RCBD) with 4 replications, 18 plants per replication (Main Plot = Cultivar, Sub Plot = PGR) for a total of 72 pots/plants. Growth data included number of stems per seedling, stem length, and stem diameter. Rhizome yield data included number of pieces of rhizome per seedling, and rhizome weights (biological, edible, and total rhizome weights respectively). Phytochemical composition analysis of ginger rhizome/PGR treatment included average amount of 6-gingerol, 8-gingerol, 10-gingerol, 6-shogoal, 8-shogoal, and 10-shogoal. Data was analyzed using SAS OnDemand for Academics with PROC GLM at α=0.05 level of significance. As ginger tissue culture seedlings progressed in culture, KT was more suitable for multiplication of buds, BA more suitable for proliferation of shoots, and KT matured ginger tissue culture seedlings at a higher rate than BA. CW had the highest rhizome yield and least amount of biological roots in comparison to other cultivars. CW produced the least amount of 8-gingerol, 10-gingerol, 8-shogoal and 10-shogoal of all three cultivars and with no significant change between two PGR treatments. In comparison, HY produced the highest amount of 6-gingerol, 8-gingerol, 10-gingerol, 6-shogoal, and 8-shogoal, followed by KY and CW, when micropropagated with BA. KY produced the highest amount of 10-shogoal when micropropagated with BA and the highest amount of 6-gingerol, 6-shogoal, 8-shogoal, and 10-shogoal when micropropagated with KT.

Effect of Pinching, Paclobutrazol and Kinetin on the Growth and Flowering of Cassia Occidentalis

The experiment was conducted in lath house of the Agricultural Preparatory School / Abi Ghareq for the spring season 2022_2023 to study the effect of fencing and spraying with paclobuterol and kinetin and its interaction on the growth and flowering traits of Cassia Occidentalis. Where the symbol for pinching is C1 and no edging is C0, the plants were sprayed with three concentrations of paclobetrazole with two concentrations (0, 0.5 and 1 g. L-1) and its symbol is (P0, P1, P2), and the plants were sprayed with kinetin at concentrations (0, 50 and 100 mg.L-1) and its symbol (K0, K1, K2. It was a split-plot factorial experiment (2*3*3) with three replicates using a Complete Randomized Blocks Design (R.C.B.D).Pinching was the main plot and paclobetrazole, kinetin, and their interactions were the subplot in each replication with 18 treatments and five plants per experimental unit (one plant per pot). The averages were compared using the Least Significant Difference L.S.D test at the 5% level, and the results showed excelled of edging on without pinching in the traits of the leaf area (587.75 cm2) and the number of flowering inflorescences (3.33 inflorescences.plant-1), The treatment of paclobetrazole with a concentration of (1 g.L-1) excelled in plant height (17.15 cm), leaf area (346.17 cm2), length of internodes (1.94 cm), and number of inflorescences (2.7 inflorescences. plant-1). While the treatment of kinetin with a concentration of (100 mg.L-1) excelled in length of the internodes (1.66 cm), the diameter of the flower (3.13 cm), while the treatment of Kinetin with a concentration of (50 mg.L-1) excelled in leaf area (630.20 cm2).

Callogenesis of Dayak Onion (Eleutherine palmifolia) Bulb in response of Picloram, 2,4-D, and Kinetin

Dayak onion contains bioactive compounds that are traditionally used for medicine. The production of bioactive compounds can be increased through callus culture. This study aims to analyze the effect of the combination of plant growth regulator on the growth of Dayak bulb callus. The design of this study used a completely randomized factorial design with 2 factors. The first factor is the concentration of auxin. While the second factor is the concentration of kinetin. The parameters observed include the percentage of callus, the time of callus formation, fresh weight, dry weight, and callus morphology. In this study, a callus growth curve was also made to determine the best harvest time. The results showed that highest callus fresh weight was obtained in the P3K1 treatment. The percentage of callus formation in the picloram + kinetin treatment was higher than in the 2,4-D + kinetin treatment. The time of callus formation occurred in the combination of picloram + kinetin faster than the 2.4-D + kinetin treatment. The callus color is diverse, while the texture of the entire callus is compact. The best callus induction medium for Dayak onion bulbs is to use picloram 2-4 ppm + kinetin0.025-0.5 ppm. The results of this study provide optimal growth regulatory information for the induction of dayak onion callus that has never been reported before. This information can be the basis for the development of methods of production of bioactive compounds from dayak onions through callus culture.

The Role of Selected Treatments in the Parameters of Leaf Growth and Yield of Stevia Plants Under Deficit Irrigation System

A field experiment was conducted at Research Station A, which is one of the research stations affiliated with the College of Agricultural Engineering Sciences - University of Baghdad (Al-Jadriya), at a cloth house (Saran) and a shading rate of 25%. The study aimed to increase the plant yield, whether foliar or of the active compounds, and link water consumption with the presence or absence of the leaf area (plant cutting). The experiment was carried out using the randomized complete block design (RCBD) according to the split-plot design arrangement with three replicates. Each main experimental unit contained 5 rows (representing secondary units), where the distance between one row and another was 75 cm, and between plants 20 cm. Then, a separation distance was left between the main experimental units of 1.5 m. The main plots represented the irrigation factor (I1 full irrigation treatment, I2 deficit irrigation treatment with an amount of 50% of the amount of water added to the comparison treatment for two irrigations immediately after cutting. Besides, I3 deficit irrigation for three irrigations immediately after cutting). Conversely, the sub-plots were represents all treatments that treated after 30 days of cutting, which is the comparison and spraying of kinetin with a concentration of 10 mg.L-1. Plus, spraying the growth retardant Cycocel (CCC) with a concentration of 100 mg.L-1, pinching and spraying Licorice extract with a concentration of 5 mg.L-1. The experiment results showed a significant decrease in the number of branches, leaf area, and leaves dry weight with each increase in the irrigation level of the first and second cuttings. However, the number of leaves and the content of chlorophyll decreased with each increase in the irrigation level of the first cutting, and the relative water content decreased with each increase in the irrigation level of the second cutting. All treatments were superior to the comparison treatment in the number of branches and the yield of dry leaves in the first and second cuttings. The treatments of pinching and Cycocel were significantly superior to the two comparison treatments and Licorice in the number of leaves per plant in the first cutting, and the treatments of kinetin and Licorice were superior to all treatments in the leaf area in the second cutting. Also, the treatments of Licorice, kinetin, and cycocel were significantly superior to the comparison and pinching treatments in the relative water content in the second cutting. Though the treatment of kinetin was significantly superior to all treatments in the content of chlorophyll A in the first and second cutting, and the treatment of kinetin was significantly superior to the comparison, cycocel and pinching treatments in the content of chlorophyll b in the first cutting.

Exogenous Kinetin Modulates ROS Homeostasis to Affect Heat Tolerance in Rice Seedlings.

Heat stress caused by rapidly changing climate warming has become a serious threat to crop growth worldwide. Exogenous cytokinin (CK) kinetin (KT) has been shown to have positive effects in improving salt and drought tolerance in plants. However, the mechanism of KT in heat tolerance in rice is poorly understood. Here, we found that exogenously adequate application of KT improved the heat stress tolerance of rice seedlings, with the best effect observed when the application concentration was 10-9 M. In addition, exogenous application of 10-9 M KT promoted the expression of CK-responsive OsRR genes, reduced membrane damage and reactive oxygen species (ROS) accumulation in rice, and increased the activity of antioxidant enzymes. Meanwhile, exogenous 10-9 M KT treatment significantly enhanced the expression of antioxidant enzymes, heat activation, and defense-related genes. In conclusion, exogenous KT treatment regulates heat tolerance in rice seedlings by modulating the dynamic balance of ROS in plants under heat stress.

Seed germination and in vitro propagation of three threatened endemic South African Aloe species

Aloe modesta Reynolds (endangered), A. peglerae Schönland (critically endangered), and A. reitzii Reynolds (vulnerable) are endemic South African Aloe species valued for their horticultural and/or medicinal value, appearing on the Red List of South African Plants. Propagation is an important step in the cultivation of these species for their conservation. This study examined the effect of temperature (15, 20, 25, and 30°C) and photoperiod (constant dark, 16 h light, and constant light) on seed germination of these three species. The in vitro propagation of A. reitzii was also investigated by examining the effect of different cytokinins [kinetin, 6-benzyladenine (BA), meta-topolin (mT), and meta-topolin riboside (mTR)] on shoot multiplication. Germination percentage and mean germination rate of A. modesta were significantly inhibited when the seeds were incubated at a low temperature (15°C) in comparison to incubation at other temperatures (20 – 30°C). An increase in temperature significantly decreased mean germination time (MGT), as well as increased seedling chlorophyll and carotenoid contents in A. peglerae and A. reitzii. A reduction in germination speed, evident in increased MGT was observed in the three species when seeds were incubated under constant light and 16 h light as compared to constant dark. Medium with 5.0 µM meta-topolin produced the highest A. reitzii shoot proliferation (16 shoots) per shoot-tip explant after eight weeks of culture. This shoot multiplication rate translates to a potential production of 1 118 481 shoots per shoot-tip explant per annum, based on a geometric progression with six possible multiplication cycles per annum. Aloe reitzii shoots produced from BA and kinetin treatments had a high flavonoid content whereas all mT and mTR treatments gave reduced flavonoid content. Seed and/or in vitro propagation protocols of these threatened endemic Aloe species established in this study can be employed in the biodiversity conservation of Aloe species for their sustainable use.

In Vitro Regeneration of Tea (Camellia sinensis (L). O. Kuntze) By Somatic Embryogenesis from Immature Cotyledon Tissues

Tea (Camellia sinensis) is the world's most popular beverage plant, as well as an important plantation crop with high commercial value. It has been maintained for centuries through conventional vegetative propagation. Tea clonal propagation in vitro has the advantage of producing a large number of elite plants. If an efficient in vitro regeneration technology is available, this technique could be exploited for selection of tea plants for desired trait. The selected plants could be later on multiplied through in vitro or ex vitro techniques. The study aimed to induced somatic embryogenesis from immature embryo explants to genetic variaton. Different concentrations of phenylboronic acid with benzyladenine and phenylboronic acid with kinetin were tested in MS medium with 30 g/L sucrose and 8 g/L agar. MS medium without any plant growth regulators was used as control group. Considering the embryo survival rate, 1.5 mg/ L-1 phenylboronic acid + 1 mg/ L-1 kinetin produced highest result as 87.3% while lowest was in control group as 36.7%. The highest plant regeneration rate was found in 1,5 mg/ L-1 phenylboronic acid + 1 mg/ L-1 kinetin and 1.5 mg/ L-1 phenylboronic acid + 1 mg/ L-1 benzyladenine medium respectively as 58.3% and 55.6%. Kinetin treatment with increasing phenylboronic acid concentrations gave the best results in terms of somatic embryo survival rate. Also, kinetin treatment produced better results when compared to benzyladenine concentrations.

Diverse Effect of Two Cytokinins, Kinetin and Benzyladenine, on Plant Development, Biotic Stress Tolerance, and Gene Expression.

The plant hormones cytokinins affect a various array of plant growth and development processes as well as responses to biotic and abiotic stresses. In this study, the opposite effect of two different cytokinins kinetin (N6-furfuryladenine) and benzyladenine (BA) on development and on the tolerance of Arabidopsis and tobacco plants to virus, bacteria, and fungi infection was reported. Treatments of Arabidopsis and tobacco seedlings with saturated solutions of BA inhibited plant progress, while treatments with saturated water solution of kinetin promoted plant development. Furthermore, BA pre-treatments strongly reduced the number of TMV (Tobacco mosaic virus) lesions on tobacco and the tissue damage caused by the incompatible Pseudomonas bacteria on Arabidopsis and tobacco leaves. Similarly, BA pre-treatment significantly reduced the necrotic disease symptoms of Botrytis cinerea infection. Kinetin pre-treatments had a much weaker or no protective effect on the damage caused by the above pathogens. Accordingly, Arabidopsis gene expression profiles after treatments also showed that the two cytokinins have different effects on several plant processes. The gene expression results supported the more robust effect of BA, which up and downregulated more than 2000 genes, while only 436 genes were influenced by kinetin treatment. It is noteworthy that BA and kinetin treatment changed gene expressions in the same direction only in a relatively few cases (73 upregulated and 70 downregulated genes), and even 28 genes were regulated into the opposite directions by BA and kinetin. Both treatments had a strong effect on auxin and gibberellin-related genes, but only BA had a significant effect on cytokinin-induced processes. While kinetin exclusively activated the flavonoid synthesis genes, BA affected more significantly protein synthesis, photosynthesis, and plant defence-related genes. In conclusion, BA solution had sometimes the opposite and generally a much stronger effect than kinetin solution not only on the development and on biotic stress tolerance of tobacco and Arabidopsis plants but also on the gene expressions. The stronger protective effect of BA to necrotic stresses is probably due to its stronger senescence inhibitory effect on plant tissues, as supported by the stronger chlorophyll retardation of the BA-treated leaves.

IAA combine with kinetin elevates the α-linolenic acid in callus tissues of soybean by stimulating the expression of FAD3 gene

Soybean is a major source of essential fatty acids such as linoleic acid and α-linolenic acid (ALA) where the ALA content is approximately 8.0% which is highly essential for human to synthesize omega 3 fatty acids. To improve the ALA content in soybean, different plant growth plant growth regulators were used in various combinations to induce the callus. In this study, six different combinations of Plant growth Regulators (PGRs) viz, 1) 2,4-D (5 μM) + TDZ (10 μM), 2) 2,4-D (5 μM) + BAP (10 μM), 3) GA3 (5 μM) + Zeatin (1 μM), 4) IAA (5 μM) + Kinetin (10 μM) 5) NAA (10 μM) + IBA (1 μM), 6) 2,4-D (5 μM) + Picloram (1 μM) were evaluated for the gene expression and fatty acid analysis. Within these treatments, IAA (5 μM) + Kinetin (10 μM) showed good proliferation of embryogenic callus with green and friable tissue. Further, mRNA expression analysis showed the varied expression of fatty acid biosynthetic genes like KASI, KASII, SCAPD, FAD2, and FAD3 in callus tissues. The callus tissue regenerated from the IAA (5 μM) + Kinetin (10 μM) treatment was found to be effective in up-regulating the FAD3 gene thereby promoting the production of ALA (up to 20.26%) than the control and any other PGR combinations tested. And hence, it may be concluded that the combination of PGR i.e. IAA (5 μM) with Kinetin (10 μM) enhanced the FAD3 gene expression and thereby improved the ALA production in soybean. Further this PGR combination need to be tested in field condition to validate the ALA content in soybean seeds.

Induction of Apple Cucumber (Cucumis melo) Buds Development by Combination of Kinetin and IAA In B5 (Gamborg) Medium

Research on indirect organogenesis of apple cucumber (Cucumis sp.) Was conducted from June until August 2020. The aim of the study is to get the best results from IAA and Kinetin concentrations on the growth of buds organogenesis to apple cucumber plants (Cucumis sp.) in B5 Gamborg Medium. The method used was an experimental method with nonparametric statistics with 25 treatments that were repeated 5 times and analyzed descriptively by the Kruskal Wallis test. The results showed that growth of apple cucumber shoots at the best combination treatment of IAA and Kinetin that is at concentrations 2,5x10-7 IAA and 3,2x10-5 Kinetin (A3B1) which resulted in appear shoots time at 39 days after initiation (hsi), it can provide the best growth of shoot height of 0,4 cm and the highest number of a shoot is 3. However, treatment with concentration 2,0x10-7 M IAA and 4,4x 10-5 Kinetin (A2B2) resulted in appearing shoots time at 39 days after initiation (hsi) and shoot height of 0,35 cm.

Effects of exogenous KT and BA on fruit quality in strawberry (Fragaria vesca)

ABSTRACT Due to developing production methods and increasing consumption levels, improvement of fruit quality has become a focus of research. Cytokinins are important hormones that affect fruit quality. In this study, exogenous KT (Kinetin) and BA (6-Benzylaminopurine) were applied 1, 3, 5, 7 and 9 days after pollination to study the effect of cytokinins on the quality of strawberry (Fragaria vesca) fruit. The results showed that exogenous KT and BA significantly increased the weight and soluble sugar content of strawberry fruit at late stages of fruit development (27 and 31 DAP). KT and BA treatments up-regulated the expression levels of FvePAL6, FveCHS, FveMYB1, and FveMYB10 at 31 DAP, thus increasing the anthocyanin content. At the red fruit stage, the anthocyanin content of fruits treated with KT and BA were 1.59 and 1.45 times, respectively, higher than that of the control. KT and BA elevated the levels of antioxidants such as ascorbic acid and total phenolics. Also, KT and BA increased the content of myricetin, quercetin, and kaempferol. In addition, KT and BA reduced the relative contents of several aromatic substances. Our results indicate that KT and BA treatments had a significant effect on the improvement of strawberry fruit quality.

A PRELIMINARY STUDY OF IN VIVO INJECTION OF AUXIN AND CYTOKININ INTO Rafflesia patma Blume FLOWER BUDS

The controlling mechanisms for the growth and differentiation of Rafflesia from a flower bud into the anthesis stage is currently unknown, particularly if any plant growth regulator (PGR) physiological pathways play some type of roles. In the wild, the number of flower buds available to study are extremely limited. In this study, we grouped six flower buds of Rafflesia patma Blume into three different treatments: two buds injected with auxin (indoleacetic acid, IAA), two buds injected with cytokinin (kinetin), and two buds injected with sterile distilled water as a control. Buds enlarged with both IAA and kinetin treatments compared to the control, but only buds injected with IAA showed a transition stage with the bract revealed (cupule-bract stage from previously cupule stage) within two weeks of five weeks of observation. These results raise further questions whether Rafflesia development is more likely due to auxin exposure when in flower bud as compared to cytokinin. Future studies should include increased sample size for treatments, enhanced PGR administration to allow exposure to the tissue and less tissue damage, injection of other PGRs such as gibberellin (GA) and jasmonic acid (JA), and histological tissue analysis to investigate PGR effects in depth.

STUDY OF KINETIN TRAETMENT ON GROWTH AND ACTIVITY OF SOME ANTIOXIDANT ENZYMES OF SPINACH UNDER SALT STRESS

Soil salinity reduces water availability of plant roots via negative (low) osmosis potential, as well as decrease of germination dynamics of plant seeds by ionic toxicity of Na and Cl, Significant differences in fruit-set, yield, photosynthetic rates, stomatal conductance, total chlorophyll content, proline, In general, salinity affects almost every aspect of the physiology and biochemistry of plants. This experiment was conducted on a private farm in Babylon Governorate at the period from 1/10/ 2013 to 15/5/ 2014, to study the effect of Kinetin treatment with three concentrations (0, 20 & 40 mg /liter ) and the quality of irrigation water in three levels ( 1.3 , 5 & 10) dS.m-1 the water salinity increased the POX and CAT activity, sodium and proline contents in leaves, resulting in decreased growth and leaf contents of NPK, The Kinetin applications alleviated negative effects of saline water by increasing dry weights of roots and NPK contents in leaves with an increasing of POX and CAT activity, and reduction of sodium contents in leaves.

Combined kinetin-morphactin application delays petal senescence in cut flower sticks of Polianthes tuberosa

To assess the role of kinetin (KN) and morphactin (MOR) separately and also in combination in the regulation of petal senescence, cut flower sticks of <i>Polianthes tuberosa</i> were placed in various holding (vase) solutions like sucrose (0.1M), kinetin (KN, 20 pM), morphactin (MOR, 20 pM), KN (20 pM) + MOR (20 pM) and sucrose (0.1M) + KN (20 pM) + MOR (20 pM). Holding solutions were taken in sterilized conical flasks and the whole set up was placed under fluorescent tubes (40 Lux light intensity). A combination of sucrose + KN + MOR was the best followed by KN + MOR in partly controlling the loss of moisture content and flower turgidity, as well as a rapid decline in the fresh weight of flower sticks during 4-day as witnessed in treated and control sets. It was also noticed that both plant growth regulators (PGRs) when applied together and when sucrose was included, became more effective in maintaining relatively higher values of flower diameter. Investigation on selected biochemical changes revealed a sharp increase in reducing and total sugars of petals of untreated flower sticks, and KN treatment was found to be the best in arresting sugar accumulation. For the retention of protein, holding solution having sucrose + KN + MOR was the best while lipid peroxidation was arrested by KN+MOR but sucrose application alone was more effective in reducing this process. This study revealed a sharp increase in proline content in untreated tuberose petals, while reduced to some extent by sucrose and further reduction by MOR and KN. Sucrose was found to be the least effective in lowering the proline level.

Cytokinin-like effects of chitosan on in vitro culture of Origanum vulgare L.

Oregano (Origanum vulgare L.) is a multi-purpose plant species with medicinal, culinary, and ornamental merit, which needs to be produced at an industrial scale. In the present research, effects of N-acetylated (10%) chitosan (CHT), 6-benzylaminopurine (BAP), and kinetin (KIN) on in vitro seed germination and shoot development in O. vulgare were studied in a concentration-dependent manner. The seed germination and shoot induction rates were mostly enhanced after CHT and KIN treatments, while BAP treatments reduced the rates. The chitosan treatment significantly triggered leaf production and shoot elongation better than the cytokinin treatments. The maximum shoot length (4.38±0.17 cm) and leaf number (17.71±0.69 leaves per shoot) were reached after chitosan treatment at 0.75 mg L-1, while shoot numbers were reduced after all chitosan and cytokinin treatments at low levels. However, shoot production was significantly enhanced in the presence of 2.0 and 4.0 mg L-1 KIN in the medium. Adventitious rooting without using auxins also occurred during the incubation period. The cluster analysis showed that the effects of 0.50 and 0.75 mg L-1 CHT treatments were better than BAP and KIN in stimulating shoot growth and leaf development in oregano. This study suggested that CHT might be used as a substitute for synthetic cytokinins to produce longer shoots and a high number of leaves in oregano propagation. Therefore, CHT might play a cytokinin-like role in plant tissue cultures. However, the effects of chitosan treatment might differ among species and according to its chemical structure

Kinetin modulates physiological and biochemical attributes of Vigna radiata L. seedlings exposed to 2-benzoxazolinone stress

Cytokinins are growth regulators concerned with influencing numerous plant metabolic and stress adaptive mechanisms under adversity. The present investigation was conducted to study the role of kinetin (KN) in ameliorating the damaging effects of allelochemical 2-benzoxazolinone (BOA) on Vigna radiata seedlings. The experiment was undertaken in sand culture under glasshouse conditions where plants were exposed to BOA (1 and 1.5 mM) by root and KN (1 mM) foliarly and then sampled for different growth parameters. BOA at both concentrations induced growth retardation which was more pronounced at the higher dose (1.5 mM). BOA toxicity gradually decreased photosynthetic pigment, relative water, protein, anthocyanin content, nitrate reductase activity and antioxidant enzyme activity. On contrary, enhanced electrolyte leakage (EL), lipid peroxidation (LP), hydrogen peroxide (H2O2), proline content and phenylalanine ammonia lyase activity (PAL). The foliar KN supplementation assisted in growth restoration by influencing several physiobiochemical attributes. KN-induced growth amelioration was reflected as reduced generation of reactive oxygen species and membrane stability with reduced LP and EL. The seedlings exposed to combined BOA and KN treatment exhibited higher antioxidant enzyme activity and total phenolic content (TPC) coupled with proline accumulation which play significant role in combating stress efficiently. The results revealed that KN has potential to buttress the defence system of crops grown in soil having higher BOA content. In future, research emphasis should be given on gene regulation mechanisms by allelopathins in plant system.

Modulatory and Toxicological Perspectives on the Effects of the Small Molecule Kinetin.

Plant hormones are small regulatory molecules that exert pharmacological actions in mammalian cells such as anti-oxidative and pro-metabolic effects. Kinetin belongs to the group of plant hormones cytokinin and has been associated with modulatory functions in mammalian cells. The mammalian adenosine receptor (A2a-R) is known to modulate multiple physiological responses in animal cells. Here, we describe that kinetin binds to the adenosine receptor (A2a-R) through the Asn253 residue in an adenosine dependent manner. To harness the beneficial effects of kinetin for future human use, we assess its acute toxicity by analyzing different biochemical and histological markers in rats. Kinetin at a dose below 1 mg/kg had no adverse effects on the serum level of glucose or on the activity of serum alanine transaminase (ALT) or aspartate aminotransferase (AST) enzymes in the kinetin treated rats. Whereas, creatinine levels increased after a kinetin treatment at a dose of 0.5 mg/kg. Furthermore, 5 mg/kg treated kinetin rats showed normal renal corpuscles, but a mild degeneration was observed in the renal glomeruli and renal tubules, as well as few degenerated hepatocytes were also observed in the liver. Kinetin doses below 5 mg/kg did not show any localized toxicity in the liver and kidney tissues. In addition to unraveling the binding interaction between kinetin and A2a-R, our findings suggest safe dose limits for the future use of kinetin as a therapeutic and modulatory agent against various pathophysiological conditions.

Combined kinetin-morphactin application delays petal senescence in cut flower sticks of Polianthes tuberosa

To assess the role of kinetin (KN) and morphactin (MOR) separately and also in combination in the regulation of petal senescence, cut flower sticks of <i>Polianthes tuberosa</i> were placed in various holding (vase) solutions like sucrose (0.1M), kinetin (KN, 20 pM), morphactin (MOR, 20 pM), KN (20 pM) + MOR (20 pM) and sucrose (0.1M) + KN (20 pM) + MOR (20 pM). Holding solutions were taken in sterilized conical flasks and the whole set up was placed under fluorescent tubes (40 Lux light intensity). A combination of sucrose + KN + MOR was the best followed by KN + MOR in partly controlling the loss of moisture content and flower turgidity, as well as a rapid decline in the fresh weight of flower sticks during 4-day as witnessed in treated and control sets. It was also noticed that both plant growth regulators (PGRs) when applied together and when sucrose was included, became more effective in maintaining relatively higher values of flower diameter. Investigation on selected biochemical changes revealed a sharp increase in reducing and total sugars of petals of untreated flower sticks, and KN treatment was found to be the best in arresting sugar accumulation. For the retention of protein, holding solution having sucrose + KN + MOR was the best while lipid peroxidation was arrested by KN+MOR but sucrose application alone was more effective in reducing this process. This study revealed a sharp increase in proline content in untreated tuberose petals, while reduced to some extent by sucrose and further reduction by MOR and KN. Sucrose was found to be the least effective in lowering the proline level.

Practical Methods for Breaking Seed Dormancy in a Wild Ornamental Tulip Species Tulipa thianschanica Regel

The innate physiological dormancy of Tulipa thianschanica seeds ensures its survival and regeneration in the natural environment. However, the low percentage of germination restricts the establishment of its population and commercial breeding. To develop effective ways to break dormancy and improve germination, some important factors of seed germination of T. thianschanica were tested, including temperature, gibberellin (GA3) and/or kinetin (KT), cold stratification and sowing depth. The percentage of germination was as high as 80.7% at a constant temperature of 4 °C, followed by 55.6% at a fluctuating temperature of 4/16 °C, and almost no seeds germinated at 16 °C, 20 °C and 16/20 °C. Treatment with exogenous GA3 significantly improved the germination of seeds, but KT had a slight effect on the germination of T. thianschanica seeds. The combined treatment of GA3 and KT was more effective at enhancing seed germination than any individual treatment, and the optimal hormone concentration for the germination of T. thianschanica seeds was 100 mg/L GA3 + 10 mg/L KT. In addition, it took at least 20 days of cold stratification to break the seed dormancy of T. thianschanica. The emergence of T. thianschanica seedlings was the highest with 82.4% at a sowing depth of 1.5 cm, and it decreased significantly at a depth of &gt;3.0 cm. This study provides information on methods to break dormancy and promote the germination of T. thianschanica seeds.

Exogenously applied plant growth regulators enhanced the yield and quality attributes of wheat (Triticum aestivum L.)

In the present investigation, a field experiment with nine treatments and three replications of each treatments was conducted with Randomized Block Design (RBD to explore effect of exogenously applied plant growth regulators on yield and quality traits of wheat crop. Wheat plants were sprayed with growth regulators at tillering and before anthesis stage, which were not only increase in the yield but also improve the quality components. The treatments were; Indole 3 Acetic Acid (IAA) 25 ppm and 50 ppm, Gibberellins (GA3) 20 ppm and 40 ppm, Cytokinin (Kinetin) 5 ppm and 10 ppm, Alar 1000 ppm and 2000 ppm. Results showed a conspicuous improvement in yield and quality traits of plant growth regulator treated plants. The yield traits such as number of ears plant-1, length of ear (cm), number of grains ear-1, grain yield plant-1, test weight and Harvest Index (HI) were found to be higher in IAA 50ppm treatment. Maximum protein content (%) was observed under the treatment of Kinetin 5 ppm. All the parameters were significantly influenced by plant growth regulators in respect to control.