• Journal of Plant Biology
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• v.20 no.2
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• pp.63-69
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• 1977

Experiments were conducted to investigate the effects of several hormones on the growth of suspension culture of carrot (Daucus carota L.) cells, where changes in pH and the amount of $NH_4-Nin$ the medium were observed with regard to growth. A treatment with 2,4-D at $10^{-5}M$ resulted in a highest rate of growth; the hormone at this concentration caused an increase in dry weight by about 40 to 50% over the control, measured at a stationary phase. It was thus indicated that 2,4-D at $10^{-5}M$ provided the optimal condition for the suspension culture. Changes in pH of the medium were found to be affected by hormonal treatments during the first 2-3 days following the inoculation, after which the pattern of pH changes in hormone enriched media paralleled that of the control. Subsequent changes of $NH_4-N and NO_3-N$ from the medium by the cells, and also by growth of the cells. The uptake of $NH_4-N$ by the cells did not appear to be influenced by hormonal treatments. At a stationary phase, a considerable amout of $NO_3-N$ played a more important role than $NH_4-N$ in the growth of the carrot cell suspension culture.

• Journal of Plant Biotechnology
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• v.42 no.4
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• pp.277-283
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• 2015

Plant genome analyses, including Arabidopsis thaliana showed a large gene family of plant receptor kinases with various extracellular ligand-binding domain. Now intensively studies to understand physiological and cellular functions for higher plant receptor kinases in diverse and complex biological processes including plant growth, development, ligands perception including steroid hormone and plant-microbe interactions. Brassinosteroids (BRs) as a one of well know steroid hormone are plant growth hormones that control biomass accumulation and also tolerance to many biotic and abiotic stress conditions and hence are of relevance to agriculture. BRI1 receptor kinase, which is localized in plasma membrane in the cell sense BRs and it bind to a receptor protein known as BRASSINOSTEROID INSENSITIVE 1 (BRI1). Recently, we reported that BRI1 and its co-receptor, BRI1-ASSOCIATED KINASE (BAK1) autophosphorylated on tyrosine residue (s) in vitro and in vivo and thus are dual-specificity kinases. Other plant receptor kinases are also phosphorylated on tyrosine residue (s). Post-translational modifications (PTMs) can be studied by altering the residue modified by directed mutagenesis to mimic the modified state or to prevent the modification. These approaches are useful to not only characterize the regulatory role of a given modification, but may also provide opportunities for plant improvement.

• The Plant Pathology Journal
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• v.36 no.1
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• pp.1-10
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• 2020

Since salicylic acid (SA) was discovered as an elicitor of tobacco plants inducing the resistance against Tobacco mosaic virus (TMV) in 1979, increasing reports suggest that SA indeed is a key plant hormone regulating plant immunity. In addition, recent studies indicate that SA can regulate many different responses, such as tolerance to abiotic stress, plant growth and development, and soil microbiome. In this review, we focused on the recent findings on SA's effects on resistance to biotic stresses in different plant-pathogen systems, tolerance to different abiotic stresses in different plants, plant growth and development, and soil microbiome. This allows us to discuss about the safe and practical use of SA as a plant defense activator and growth regulator. Crosstalk of SA with different plant hormones, such as abscisic acid, ethylene, jasmonic acid, and auxin in different stress and developmental conditions were also discussed.

• Journal of Life Science
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• v.15 no.1 s.68
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• pp.112-117
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• 2005

Plants living riverside show diverse resistance responses to submergence. The promoted petiole elongation of semi-aquaitc plants, e.g., such as Ranunculus sceleratus and Rumex palustris, is one of the adaptive responses mediated by the plant hormone ethylene. The gaseous hormone is trapped in submerged plant tissues and enhances the petiole growth by increasing sensitivity of the tissues to some plant hormones including auxin. Due to the stimulated growth of petioles, the leaves finally reach the water surface and can respirate again. At the water surface, the accumulated ethylene diffuses out from the tissues to the air. As a result, the increased hormone sensitivity decreases again, and thus the growth rate reduces to the basal level as before. The increased auxin sensitivities by ethylene observed in Ranunculus sceleratus, revealed by the changes in the auxin dose-response curves, indicate the increase of affinities of the receptors to auxin. However, the molecular mechanism of the affinity regulation remains still largely unknown, because the identity of the auxin receptor is still unclear.

• Journal of Photoscience
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• v.10 no.1
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• pp.157-164
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• 2003

Light exerts two primary roles in plant growth and development. Plants acquire all biochemical energy required for growth and propagation solely from light energy via photosynthesis. In addition, light serves as a medium through which plants recognize environmental fluctuations, such as photoperiod and presence of neighboring animals and plants. Plants therefore constantly monitor the direction, intensity, duration, and wavelength of environmental light and integrate these light signals into the intrinsic regulatory programs to achieve an optimized growth in a given light condition. Although light regulates all aspects of plant growth and developmental aspects, the molecular mechanisms and signaling cascades involved have not been well established until recently. However, recent advances in genetic tools and plant transformation techniques greatly facilitated the elucidation of molecular events in plant photomorphogenesis. This mini-review summarizes the gist of recent findings in deetiolation and suppression of shade avoidance response as classic examples of the phytochrome-mediated photomorphogenesis.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.s01
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• pp.16-25
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• 1989

A bioassay is a test system using a living organism (in whole or in part) to determine the presence or relative potency of chemical substances. The development and uses of bioassay are intimately linked to the discovery and characterization of the major classes of plant hormones. An application of this relationship is helpful for understanding the concept of plant hormones as well as the use of bioassay. And plant bioassay have been development and employed not only for the discovery and characterization of the biological activity of plant growth regulators but also have served several important secondary roles. The ideal bioassay should possess the characteristic of high specificity. great sensitivity. short response time, low cost and ease of obtaining plant material. acceptable ease of manipulation, and minimal space and equipment requirements.

• Plant Biotechnology Reports
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• v.4 no.3
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• pp.179-183
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• 2010

Ethylene is a key gaseous hormone that controls various physiological processes in plants including growth, senescence, fruit ripening, and responses to abiotic and biotic stresses. In spite of some of these positive effects, the gas usually inhibits plant growth. While chemical fertilizers help plants grow better by providing soil-limited nutrients such as nitrogen and phosphate, overusage often results in growth inhibition by soil contamination and subsequent stress responses in plants. Therefore, controlling ethylene production in plants becomes one of the attractive challenges to increase crop yields. Some soil bacteria among plant growth-promoting rhizobacteria (PGPRs) can stimulate plant growth even under stressful conditions by reducing ethylene levels in plants, hence the term "stress controllers" for these bacteria. Thus, manipulation of relevant genes or gene products might not only help clear polluted soil of contaminants but contribute to elevating the crop productivity. In this article, the beneficial soil bacteria and the mechanisms of reduced ethylene production in plants by stress controllers are discussed.

• Journal of Plant Biotechnology
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• v.7 no.3
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• pp.161-167
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• 2005

Brassinosteroids are steroidal plant hormones and are known to modulate physiological and cellular response in a wide range of plant species. Considerable insights has been achieved of the physiological role of brassinosteroid in Brassica species in the past few years, but their effect on direct organogenesis has not been extensively studied. In this sense, under optimal basal media and growth conditions we tested the cellular and organogenic response of 24-epibrassinolide (EBL) in a variable concentration (0.1 to $5.0\;{\mu}M$) and Zeatin (Z) (1.0 to $100\;{\mu}M$) and their synergic effect on hypocotyl explants of cauliflower and broccoli. The isolated EBL accelerated cell elongation and promotes direct organogenesis. One micromolar EBL + $10\;{\mu}M$ of Z was the most efficient combination for cell elongation, cell differentiation as well as for organogenesis. A suppressing effect on root induction was confirmed for all the tested hormone levels. The general results indicate a synergic effect of EBL-Z and EBL potentates Zeatin activity, at least in certain tissues. Besides de genetic factors, we can speculate that the natural hormone concentration in the explants might affect the responses by application of exogenous growth regulators. Experiments with new plant growth regulators, like brassinolide, are important aiming to maximize or accelerate plant regeneration for in vitro multiplication or for genetic transformation.

• Journal of Digital Convergence
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• v.13 no.9
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• pp.523-530
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• 2015

This study was tested growth hormone and fatigue materials after eight-week high-intensity interval exercise to middle aged women (40's~50's women) who have been obesity without other disease. Two group of 20 candidates were randomly divided 10 persons as exercise group and control group. Exercise was conducted 8 weeks 4 days 35 minutes, before the study each group was checked vital sign for fatigue materials. It showed the following results. First, it has been increased growth hormone level after exercise program compared each group, significantly. Secondly, it has been decreased fatigue materials due to the high-strength interval workout for 8 weeks compared control as significantly. As a result, eight-week high-intensity interval exercise could be increased growth hormone levels by reducing fatigue and it might be preventing fatigue materials levels. We would suggest that high-strength interval workout for 8 weeks could have a positive effect for preventing and reducing fatigue and related disease, obesity.

• FLOWER RESEARCH JOURNAL
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• v.26 no.4
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• pp.179-186
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• 2018

Ranunculus asiaticus characterizes colorful and attractive flower shapes that are related with the ornamental value of bulbous plants. Improving ornamental value of bulbous flowers has been the general goal of floricultural market. Gibberellic acid ($GA_3$) and benzyladenine (BA) play an important role in growth and developmental processes in floriculture. Combinational treatments of these two hormones have been used in floriculture to improve flower quality. We assessed the effects of combined $GA_3$ and BA, as well as the individual effects of each hormone, on growth characteristics using soil drench application to eight R. asiaticus cultivars, 'Giallo Millepetali', 'Bianco Millepetali', 'Arancio Millepetali', 'Rosa SC', 'Arancio Pratolino', 'Giallo Pratolino', 'Bianco Pratolino', and 'Rosa Ch Pratolino'. $GA_3$ treatments increased plant height and first flower size of R. asiaticus cultivars. Moreover, about 5 to 9 days to flowering were averagely shortened by $GA_3$ treatments compared to controls. On the other hand, the opposites, including first flower size and days to flowering, were observed for cultivars treated with BA, compared with controls. Treatments of $GA_3$ + BA generally affected growth traits, such as plant height, flower size, and the timing of flowering on some R. asiaticus cultivars. In particular, about 5 to 6 days to flowering were reduced on average by Treatments of $GA_3$ + BA. Our results showed positive growth effects, including plant height, days to flowering, first flower height, number of flowers from the application of individual and combined hormones to R. asiaticus cultivars and demonstrate a role for these hormones in future bulbous floriculture.