Isolation, Structure and Synthesis of Kinetin, a Substance Promoting Cell Division^1,2

A Transcriptome-Based Characterization of Habituation in Plant Tissue Culture

“…Among the genes found up-regulated by cytokinin in nonhabituated calli were several genes involved in light harvesting and photosynthesis, cell wall modification, amino acid and protein synthesis and transport, and nutrient and carbon acquisition. These findings correlate well with several known biological roles for cytokinins in planta, including promotion of greening (Stetler and Laetsch, 1965;Daniell and Rebeiz, 1982), cell division (Miller et al, 1956), and protein synthesis (Maaß and Klämbt, 1977), and serving as a nutrient sink (Roitsch and Ehneß, 2000). There were also a number of genes identified that potentially highlight cross talk between cytokininsignaling and other signaling pathways, including auxin transport and signaling (At4g29080, At2g01420, At1g19840, At2g46690, At2g39730, At1g22630, At2g33830, At1g67700), calcium signaling (At4g33000, At1g25230, At5g54130), brassinosteroid synthesis (At4g13290, At1g78490, At4g13770, At2g34490, At3g26330, At3g03470, At2g22330), GA 3 synthesis (At1g06640, At5g59530), and ethylene responses (At5g07580, At5g61590).…”

“…Cytokinins are a family of N 6 -substituted adenine derivatives whose stimulation of cell division and organogenesis in plants has been studied since the discovery of the first cytokinin, kinetin, in 1956 (Miller et al, 1956). The isolation of triple mutants in the Arabidopsis cytokinin-receptor family (AHK2, AHK3, and CRE1) has confirmed that cytokinins are essential for appropriate plant growth and development, as these plants are infertile and have severely stunted growth (Higuchi et al, 2004).…”

Multiple Type-B Response Regulators Mediate Cytokinin Signal Transduction in Arabidopsis

“…arr Mutants Have an Altered Response to Cytokinin in Callus/Greening Assays Cytokinins, in concert with auxin, are capable of promoting cell division, greening, and shoot initiation in cultured plant tissues (Miller et al, 1956;Skoog and Miller, 1957;Mok and Mok, 2001). In addition, cytokinins inhibit root formation in cultured plant tissues (Skoog and Miller, 1957;Mok and Mok, 2001).…”

Factors in Corn Steep Water Promoting Growth of Plant Tissues.

“…It may be that this effect of kinetin alone was dependent upon a carryover of corn steep factors from the previous substrate. The high concentration of kinetin necessary is in sharp contrast to the low levels required in culture of some other tissues such as tobacco (5) in which excellent growth occurs with only 10-6 M and in which 2 X 10-5 M may be inhibitory. It will be interesting to learn whether or not such quantitative (lifferences in kinetin requirements are correlaterd with sensitivities to the light and dark periods.…”