Search results for: Hartwig Lüthen

Items from 1 to 14 out of 14 results

chapter

Astrophotography

Klaus-Peter Schröder, Hartwig Lüthen

Handbook of Practical Astronomy > 133-173

In the recent past, astrophotography has been revolutionised by numerous new, digital photographic devices and their corresponding software, often dedicated to very specialised tasks in astronomy. This chapter is an attempt to give a brief overview of todays most relevant imaging tools (e.g. CMOS-based DSLR, traditional SLR, cooled CCD, webcam, CCTV-camera), and how they are applied to the main tasks...

article

From Facts and False Routes: How Plant Hormone Research Developed

Jutta Ludwig-Müller, Hartwig Lüthen

Journal of Plant Growth Regulation > 2015 > 34 > 4 > 697-701

Our understanding of how plant hormones work has tremendously increased over the last decades. However, such progress was not possible without those who laid the foundation of the work which was sometimes much more tedious in early days than today. Therefore, we thought it timely to follow-up on historical aspects of plant hormone research. The development in the field of auxins, cytokinins, gibberellins,...

article

What We Can Learn from Old Auxinology

Hartwig Lüthen

Journal of Plant Growth Regulation > 2015 > 34 > 4 > 702-707

Auxin is the plant hormone with the longest history, harking back to the days of Charles Darwin. Modern research focuses on auxin signal transduction and auxin transport, and it has become more and more evident that auxin gradients shape the plant. Many of today’s successful concepts have early roots, which are easily forgotten. This review tries to highlight some of them, without striving for any...

article

A high‐throughput imaging auxanometer for roots and hypocotyls of Arabidopsis using a 2D skeletonizing algorithm

Simon Fraas, Vera Niehoff, Hartwig Lüthen

Physiologia Plantarum > 151 > 1 > 112 - 118

Next generation phenotyping of auxin response mutants will be greatly facilitated by the ability to record rapid growth responses in roots and hypocotyls at high throughput and at high temporal resolution. As Arabidopsis seedlings are very tiny and fragile, imaging is the only adequate way for data acquisition. As camera‐based systems described before have a limited throughput, we used commercial...

article

Expression of TWISTED DWARF1 lacking its in‐plane membrane anchor leads to increased cell elongation and hypermorphic growth

Aurélien Bailly, Bangjun Wang, Marta Zwiewka, Stephan Pollmann, more

The Plant Journal > 77 > 1 > 108 - 118

Plant growth is achieved predominantly by cellular elongation, which is thought to be controlled on several levels by apoplastic auxin. Auxin export into the apoplast is achieved by plasma membrane efflux catalysts of the PIN‐FORMED (PIN) and ATP‐binding cassette protein subfamily B/phosphor‐glycoprotein (ABCB/PGP) classes; the latter were shown to depend on interaction with the FKBP42, TWISTED DWARF1...

article

Rapid auxin-induced root growth inhibition requires the TIR and AFB auxin receptors

Katharina Scheitz, Hartwig Lüthen, Daniel Schenck

Planta > 2013 > 238 > 6 > 1171-1176

We investigated the relation between auxin-induced gene expression and the rapid auxin-induced growth inhibition in Arabidopsis thaliana roots. The natural auxin indole-3-acetic acid (IAA) induced a strong activation of gene expression as visualized by the DR5rev::GFP reporter gene technique. This effect was specific for active auxins and was abolished in knockout mutants of the F-box auxin receptors...

article

Differential Transcript Expression of Wall-loosening Candidates in Leaves of Maize Cultivars Differing in Salt Resistance

Christoph-Martin Geilfus, Christian Zörb, Christina Neuhaus, Tim Hansen, more

Journal of Plant Growth Regulation > 2011 > 30 > 4 > 387-395

Salt-sensitive crop plants such as maize (Zea mays L.) exhibit a strong and rapid growth reduction in response to NaCl stress. The unique salt-resistant maize hybrid SR03 and the salt-sensitive maize hybrid Lector provide good tools to characterize various genotypic responses to salinity in terms of shoot growth, shoot extensibility, and the expression pattern of wall-loosening candidates. The mRNA...

article

The auxin-binding pocket of auxin-binding protein 1 comprises the highly conserved boxes a and c

Renate I. Dahlke, Hartwig Lüthen, Bianka Steffens

Planta > 2009 > 230 > 5 > 917-924

The auxin-binding protein 1 (ABP1) has already been proved to be an extracellular receptor of auxin in single cell systems. Protoplasts of maize coleoptiles respond to auxin with an increase in volume. The 2-naphthaleneacetic acid (2-NAA), an inactive auxin analog, acts as an anti-auxin in protoplast swelling, as it suppresses the effect of indole-3-acetic acid (IAA). Antibodies raised against box...

article

Meeting Report: Botanical Congress, Hamburg, 2007

Klaus Schwartzenberg, Hartwig Lüthen

Journal of Plant Growth Regulation > 2008 > 27 > 2 > 202-203

article

The auxin-induced K⁺ channel gene Zmk1 in maize functions in coleoptile growth and is required for embryo development

Katrin Philippar, Kai Büchsenschütz, David Edwards, Julia Löffler, more

Plant Molecular Biology > 2006 > 61 > 4-5 > 757-768

The transcript level and in turn protein density of the K⁺-uptake channel ZMK1 in maize (Zea mays) coleoptiles is controlled by the phytohormone auxin. ZMK1 is involved in auxin-regulated coleoptile elongation as well as gravi- and phototropism. To provide unequivocal evidence for the role of ZMK1 in these elementary processes we screened for maize plants containing a Mutator-tagged Zmk1 gene. In...

article

New methods to analyse auxin-induced growth II: The swelling reaction of protoplasts – a model system for the analysis of auxin signal transduction?

Bianka Steffens, Hartwig Lüthen

Plant Growth Regulation > 2000 > 32 > 2-3 > 115-122

A method for monitoring the time course of auxin-induced volume changesby protoplasts at a high temporal resolution was developed for Zeamays coleoptile protoplasts. Auxins, like indole-3-acetic acid(IAA), induce a rapid change in volume. Immediately after addition ofthis auxin, a transient shrinkage was observed, followed by a long-termswelling response. This reaction occurred in the same time window...

article

New methods to analyse auxin-induced growth I: Classical auxinology goes Arabidopsis

May Christian, Hartwig Lüthen

Plant Growth Regulation > 2000 > 32 > 2-3 > 107-114

During recent years, genetic approaches have become invaluable tools to analyse signalling chains in plants. The first step to understand auxin signalling is the isolation of signal transduction mutants. In Arabidopsis, screening for auxin resistant plants has identified a number of mutants. However, it is difficult to link the mutated genes to the rapid growth response to auxin. As yet, there is...

article

Effect of IAA and 4-Cl-IAA on growth rate in maize coleoptile segments

Waldemar Karcz, Hartwig Lüthen, Michael Böttger

Acta Physiologiae Plantarum > 1999 > 21 > 2 > 133-139

The dose-response curves for IAA and 4-Cl-IAA-induced growth of Zea mays L. coleoptile segments were studied as a function of time. Moreover, some characteristic growth parameters for both auxins were compared. The dose-response curve of growth rate measured after IAA or 4-Cl-IAA application was bell-shaped in all experiments. The optimum concentration was 10⁻⁶ M for 4-Cl-IAA and was found not to...