Tagged: plant hormones


Hormone-metabolic interactions in adventitious roots

Adventitious roots are roots that form after the plant embryo has grown. They’re the roots that can grow out of stems when you make plant cuttings. Adventitious root formation is a bottleneck for the survival of isolated plant fragments. Adventitious root formation plays an important ecological role and is a critical process in cuttings for the clonal propagation of horticultural and forestry crops. Understanding the regulation of excision-induced adventitious root formation is essential for the sustainable and efficient use of plant genetic resources. Recent studies of plant transcriptomes, proteomes and metabolomes, and the use of mutants and transgenic lines have...

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Vascular and polar auxin transport re-establishment after wounding or complete severing of the stem.

Auxin transport and stem vascular reconnection – has our thinking become canalized?

The presence of a polar auxin transport stream has long been correlated with the differentiation and patterning of vascular cells across vascular plants. As our understanding of auxin transport and vascular development has grown, so too has evidence for the correlation between these processes. However, a clear understanding of the cellular and molecular mechanisms driving this correlation has not been elucidated. Wulf et al. examine the hypothesis that canalization via polar auxin transport regulates vascular reconnection and patterning in the stem after wounding or grafting. The authors investigate the evidence for the causal nature of the relationship and the suggested...

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A diagram of the matter in question

Regulatory networks controlling the development of the root system and the formation of lateral roots

The production of a new lateral root from parental root primary tissues has been investigated extensively, and the most important regulatory mechanisms are now well known. A first regulatory mechanism is based on the synthesis of small peptides which interact ectopically with membrane receptors to elicit a modulation of transcription factor target genes. A second mechanism involves a complex cross-talk between plant hormones. It is known that lateral roots are formed even in parental root portions characterized by the presence of secondary tissues, but there is not yet agreement about the putative tissue source providing the cells competent to become...

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Image: Wikimedia Commons.

Sugar versus Auxin: which is dominant?

Of the plethora of aspects of plant growth and development that the hormone (OK, plant growth regulator…) auxin is implicated in/involved with (e.g. embryo development, leaf formation, phototropism, gravitropism, fruit development, abscission, root initiation and development…), surely one of the most enduring is apical dominance. Apical dominance is the phenomenon whereby the outgrowth of buds on the side of a shoot is suppressed in favour of growth by the apical bud (hence its name…). Maintenance of this suppression has long been assumed to be due to the production of auxin by the apical bud and its transport down the stem, which effectively keeps the...

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Plant hormones in arbuscular mycorrhizal symbioses (Research in Context)

Plant hormones in arbuscular mycorrhizal symbioses (Research in Context)

Although >80% of species form arbuscular mycorrhizal symbioses, the roles of plant hormones in the associations are still being determined. Foo et al. critically review recent progress in our understanding of the roles of strigolactones, auxin, abscisic acid, ethylene, jasmonic acid and salicylic acid in mycorrhizal symbiosis, and present new evidence for a novel role for gibberellins in mycorrhizal development. Using gibberellin- and DELLA-deficient mutants of pea they show that bioactive gibberellins have a negative role in arbuscule formation. In contrast, a brassinosteriod-deficient pea mutant provides no indication of a role for these compounds in mycorrhizal development.

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