Interactions of auxin and cytokinins in regulating axillary bud formation in sunflower (Helianthus annuus L.)

Abstract

Sunflower is an important oilseed crop, known to grow a strong dominating single flower head. In recent times, axillary buds initiation and formation of multi flower heads is a common feature in many sunflower hybrids. To find out the reason for multi headedness an experiment was carried out in the hybrid KBSH-41. It was found that this trait is regulated by the interaction of environmental signals and plant growth regulators such as auxin and cytokinin. Any kind of stress induces the bud growth which affects the translocation of hormones in the transpiration system, especially auxin. When the translocation of basipetally moving auxin reduces, concentration of acropetally moving cytokinin increases leading to the development of axillary buds. When, under normal conditions,auxin to cytokinin ratio is not altered the plants develop single flower heads. The results of this study suggest that auxin has an inhibitory effect on the growth of axillary buds, while cytokinin promotes their growth. The mechanism of axillary bud growth depends on the ratio of these two hormones.

Two Growing-Season Warming Partly Promoted Growth but Decreased Reproduction and Ornamental Value of Impatiens oxyanthera

“…Both heat and water stress influence the activities of PSII and PSI and, thereby, plant growth and viability [ 40 ]. In this study, warming in 2017 promoted a number of primary branches of I. oxyanthera , which may indicate that moderate warming increased the relative content of cytokinins and promoted axillary bud growth [ 41 ]. However, warming in 2018 had no significant effect on the number of primary branches, probably because the plants had adapted to the warmed environments in 2018 after the first year of warming.…”

The Effect of Explant Type and 6-Benzyl Adenine (BAP) In Sapodilla (<i>Achras zapota</i>) Micropropagation

“…Application of exogenous cytokinin, capable of activating the lateral buds under the influence of apical dominance and proven effective in stimulating metabolic activity and growth of shoots on woody plants for example in woody plant species such as Picea abies, Abies balsamea, Macadamia teteraphylla, Pinus strobus and Pinus sylvesteris (Bhojwani and Razdan, 1996;Jafari et al, 2011: Eldoma et al, 2015. Nagarathna et al (2010) explain that, endogenous cytokinin is increase in the axillary node which is far from the top and application of exogenous cytokinin will encourage rapid shoot proliferation.…”

Effects of Some Plant Growth Regulators on Quality of Potted Sunflower

“…Plants develop single flower heads when the ratio of auxin to cytokinin does not change. Therefore, axillary bud growth may suggest that Promalin treatments altered endogenous hormone translocation and increased cytokinin levels led to axillary bud initiation (Nagarathna et al, 2010).…”