Regulation of plant growth by cytokinin
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TLDR
It is suggested that cytokinins are an important regulatory factor of plant meristem activity and morphogenesis, with opposing roles in shoots and roots.Abstract:
Cytokinins are a class of plant-specific hormones that play a central role during the cell cycle and influence numerous developmental programs. Because of the lack of biosynthetic and signaling mutants, the regulatory roles of cytokinins are not well understood. We genetically engineered cytokinin oxidase expression in transgenic tobacco plants to reduce their endogenous cytokinin content. Cytokinin-deficient plants developed stunted shoots with smaller apical meristems. The plastochrone was prolonged, and leaf cell production was only 3–4% that of wild type, indicating an absolute requirement of cytokinins for leaf growth. In contrast, root meristems of transgenic plants were enlarged and gave rise to faster growing and more branched roots. These results suggest that cytokinins are an important regulatory factor of plant meristem activity and morphogenesis, with opposing roles in shoots and roots.read more
Citations
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Journal ArticleDOI
Cytokinin Oxidase Regulates Rice Grain Production
Motoyuki Ashikari,Hitoshi Sakakibara,Shaoyang Lin,Toshio Yamamoto,Tomonori Takashi,Asuka Nishimura,Enrique R. Angeles,Qian Qian,Hidemi Kitano,Makoto Matsuoka +9 more
TL;DR: It is shown that a QTL that increases grain productivity in rice, Gn1a, is a gene for cytokinin oxidase/dehydrogenase (OsCKX2), an enzyme that degrades the phytohormone cytokinIn.
Journal ArticleDOI
Cytokinin-Deficient Transgenic Arabidopsis Plants Show Multiple Developmental Alterations Indicating Opposite Functions of Cytokinins in the Regulation of Shoot and Root Meristem Activity
TL;DR: The results are consistent with the hypothesis that cytokinins have central, but opposite, regulatory functions in root and shoot meristems and indicate that a fine-tuned control of catabolism plays an important role in ensuring the proper regulation of cytokinin functions.
Journal ArticleDOI
CYTOKININS: Activity, Biosynthesis, and Translocation
TL;DR: Recent findings on the relationship between CK structural variation and activity, distinct features in CK biosynthesis between higher plants and Agrobacterium infected plants, CK translocation at whole-plant and cellular levels, and CKs as signaling molecules for nutrient status via root-shoot communication are summarized.
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Arabidopsis Cytokinin Receptor Mutants Reveal Functions in Shoot Growth, Leaf Senescence, Seed Size, Germination, Root Development, and Cytokinin Metabolism
TL;DR: Researchers used loss-of-function mutants to study three Arabidopsis thaliana sensor histidine kinases to reveal partially redundant functions of the cytokinin receptors and prominent roles for the AHK2/AHK3 receptor combination in quantitative control of organ growth in plants, with opposite regulatory functions in roots and shoots.
Journal ArticleDOI
Signal integration in the control of shoot branching.
TL;DR: The proposal of two models are proposed, the auxin transport canalization-based model and the second messenger model, which provide mechanistic explanations for apical dominance.
References
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Journal Article
Chemical regulation of growth and organ formation in plant tissues cultured in vitro.
F Skoog,C O Miller +1 more
Journal ArticleDOI
The Stem Cell Population of Arabidopsis Shoot Meristems Is Maintained by a Regulatory Loop between the CLAVATA and WUSCHEL Genes
TL;DR: This paper showed that the shoot meristem has properties of a self-regulatory system in which WUS/CLV interactions establish a feedback loop between the stem cells and the underlying organizing center.
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Inhibition of Leaf Senescence by Autoregulated Production of Cytokinin
Susheng Gan,Richard M. Amasino +1 more
TL;DR: This result demonstrates that endogenously produced cytokinin can regulate senescence and provides a system to specifically manipulate the senescences program.
Journal ArticleDOI
Cytokinin Activation of Arabidopsis Cell Division Through a D-Type Cyclin
TL;DR: Results suggest that cytokinin activates Arabidopsis cell division through induction of CycD3 at the G1-S cell cycle phase transition.