Kinetin

About: Kinetin is a research topic. Over the lifetime, 7856 publications have been published within this topic receiving 135550 citations. The topic is also known as: Kinetin.

The physiological significance of kinetin‐ and gibberellin‐like root hormones

Abstract: Traditionally, the root has been viewed as an organ of water and salt absorption and most research in root physiology centered around these two functions. Recently it became evident that the root supplies cytokinins and gibberellins to the upper parts of the plant and that it may exert horomonal control over certain metabolic functions of the shoot. The existence of “root hormones” had been proposed by Chibnalll and Went2 almost thirty years ago. Chibnall showed that roots exerted a profound influence on protein metabolism in the leaves. The protein level of detached leaves declined unless adventitious roots developed on the petiole. Chibnall suggested that a hormonal factor from the root was responsible for normal protein metabolism of the leaves. Much later Parthies confirmed Chibnall’s experiments and demonstrated that the capacity of an excised leaf to incorporate 14C-methionine into proteins declined up to the point when the first adventitious rootlets became visible on the petiole. Thereafter, incorporation of the labeled amino acid into the proteins of the leaf increased again. Went proposed that a growth hormone (caulocaline) was supplied by the root and needed for stem growth in addition to auxins.2 This hypothesis was based on the observation that growth of the shoot was inhibited when the root was removed and could, to some extent, be restored by treating leaves of rootless tomato plants with coconut milk or pea d i f f~sa t e .~ Richmond and Lang5 discovered that kinetin (6-furfurylaminopurine) delayed senescence of detached primary leaves of Xanthium pennsylvanicum. This was reflected in the higher protein and chlorophyll level of the kinetin-treated leaves, and was the first indication that kinetin or related compounds might act like Chibnall’s hypothetical root factor. This idea was further strengthened by Mothes and Engelbrecht who subjected isolated tobacco leaves to heat stress and found that either adventitious roots or kinetin applied to the leaf blade increased the heat tolerance of the tissue.s According to these workers, kinetin or a similar factor from the root “stabilized” metabolic processes occurring in the leaf, thus rendering it less susceptible to stress. The first evidence for the occurrence of cytokinins in the transpiration stream moving from the roots to the leaves came from the work of Kulaeva7 who applied crude root exudate of tobacco plants to detached tobacco leaves. These leaves then aged more slowly than water-treated controls. The response was comparable to one induced by a low kinetin concentration, but it disappeared within a short time. Conclusive evidence for the presence of cytokinins in root exudate was obtained by Loeffler and van Overbeek,6 and Kende.gJo Loeffler and van Overbeek isolated from the bleeding sap of grape four factors which retarded chlorophyll degradation in detached radish leaves, and Kende showed the presence of

Somatic embryogenesis and regeneration of flowering plants in rose

Abstract: Somatic embryos of the cut rose cultivars 'Domingo' and 'Vickey Brown' were obtained from callus derived from leaf explants on half strength Murashige and Skoog medium with low concentrations of kinetin and 1-naphthyl acetic acid or 2-naphthyloxyacetic acid. Somatic embryos were first observed after 6 to 12 weeks of culture on callus formed at the basis or midrib of the leaf. Embryos could be grown to phenotypically true to type greenhouse plants.

High frequency plantlet regeneration from cotyledonary node cultures of Aegle marmelos (L.) Corr

Abstract: High frequency plantlet regeneration was achieved in cotyledonary nodes of Aegle marmelos Cotyledonary nodes from 1 mo old in vitro grown seedlings of A marmelos were cultured on Murashige and Skoog (MS) medium supplemented with benzyl adenine (BA) (0–88 μM), kinetin (KIN) (0–94 μM), and indole-3-acetic acid (IAA) (0–114 μM) either alone or in combinations The highest regenerative response was observed on medium containing 66 μM BA + 114 μM IAA where approximately 866% of the cultures responded with an average shoot numbers of 4875 per explant in 7-wk time Cultures maintained on KIN-supplemented medium showed very poor response In vitro responded shoots were transferred to root induction medium consisting of half-strength MS supplemented with auxins IAA, indole-3-butyric acid (IBA), or α-naphthalene acetic acid (NAA) Rooting was best in medium supplemented with 147 μM IBA Rooted plantlets were acclimatized and transferred to the field with 80% survival rate

Modification of cadmium toxicity in pea seedlings by kinetin

Abstract: The effect of foliar application of kinetin on the growth and some physiological processes of pea plants growing in soil supplemented with 25 or 50μM Cd were studied. Cadmium treatment inhibited the growth rate, chlorophyll (Chl) content, net photosynthesis (PN), content of soluble sugars and free amino acids of either shoots or roots. The application of kinetin (kin) enhanced the growth rate, Chl content, PN, soluble sugars and free amino acids content of shoots and roots; dark respiration rate (RD), contents of soluble protein and proline were increased by cadmium treatment. The addition of kinetin to Cd-stressed plant reduced RD, soluble protein and proline content. Considerable variations in the content of Na+, K+, Ca2+ and Mg2+ were induced by Cd-treatments. Foliar application of kinetin exhibited a favorable effect on the accumulation of some ions and antagonized or ameliorated the inhibitory effect of Cd stress on some others.

Callus formation from mesophyll protoplasts of Pisum sativum

Abstract: Protoplasts isolated from mesophyll of Pisum sativum L. cv. Century, and cultured in 0.2-ml droplets of B5 medium with 1.0 mg/liter (2,4-dichlorophenoxy)acetic acid (2,4-D) or 1-naphthaleneacetic acid (NAA) and 2.0 mg/liter kinetin regenerated cell walls within 2–3 days. The resulting cells began to divide and form calli after 19 days of culture. Protoplast survival depended on keeping the leaf material in the dark for at least 30 h before use.