Lateral shoot

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Lateral shoots/branches are often numerous on larger vegetation such as certain trees or bushes. Lace of tree branch (Pavlovsk park).jpg
Lateral shoots/branches are often numerous on larger vegetation such as certain trees or bushes.

A lateral shoot, commonly known as a branch, is a part of a plant's shoot system that develops from axillary buds on the stem's surface, extending laterally from the plant's stem.

Contents

Importance to photosynthesis

As a plant grows it requires more energy, it also is required to out-compete nearby plants for this energy. One of the ways a plant can compete for this energy is to increase its height, another is to increase its overall surface area. That is to say, the more lateral shoots a plant develops, the more foliage the plant can support increases how much photosynthesis the plant can perform as it allows for more area for the plant to uptake carbon dioxide as well as sunlight.

Genes, transcription factors, and growth

Through testing with Arabidopsis thaliana (A plant considered a model organism for plant genetic studies) genes including MAX1 and MAX2 have been found to affect growth of lateral shoots. Gene knockouts of these genes cause abnormal proliferation of the plants affected, implying they are used for repressing said growth in wild type plants. [1] Another set of experiments with Arabidopsis thaliana testing genes in the plant hormone florigen, two genes FT and TSF (which are abbreviations for Flowering Locus T, and Twin Sister of FT) when knocked out, appear to affect lateral shoot in a negative fashion. These mutants cause slower growth and improper formation of lateral shoots, which could also mean that lateral shoots are important to florigen's function. [2] Along with general growth there are also transcription factors that directly effect the production of additional lateral shoots like the TCP family (also known as Teosinte branched 1/cycloidea/proliferating cell factor) which are plant specific proteins that suppress lateral shoot branching. [3] Additionally the TCP family has been found to be partially responsible for inhibiting the cell's Growth hormone–releasing hormone (GHRF) which means it also inhibits cell proliferation. [4]

See also

Related Research Articles

Developmental biology is the study of the process by which animals and plants grow and develop. Developmental biology also encompasses the biology of regeneration, asexual reproduction, metamorphosis, and the growth and differentiation of stem cells in the adult organism.

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<span class="mw-page-title-main">Apical dominance</span> Phenomenon where the central stem grows stronger than other stems

In botany, apical dominance is the phenomenon whereby the main, central stem of the plant is dominant over other side stems; on a branch the main stem of the branch is further dominant over its own side twigs.

<span class="mw-page-title-main">Meristem</span> Type of plant tissue involved in cell proliferation

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<span class="mw-page-title-main">Plant hormone</span> Chemical compounds that regulate plant growth and development

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<span class="mw-page-title-main">Auxin</span> Plant hormone

Auxins are a class of plant hormones with some morphogen-like characteristics. Auxins play a cardinal role in coordination of many growth and behavioral processes in plant life cycles and are essential for plant body development. The Dutch biologist Frits Warmolt Went first described auxins and their role in plant growth in the 1920s. Kenneth V. Thimann became the first to isolate one of these phytohormones and to determine its chemical structure as indole-3-acetic acid (IAA). Went and Thimann co-authored a book on plant hormones, Phytohormones, in 1937.

<span class="mw-page-title-main">Cytokinin</span> Class of plant hormones promoting cell division

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<span class="mw-page-title-main">Gravitropism</span> Plant growth in reaction to gravity

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<span class="mw-page-title-main">ABC model of flower development</span> Model for genetics of flower development

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<span class="mw-page-title-main">Primordium</span> Organ in the earliest recognizable stage of embryonic development

A primordium in embryology, is an organ or tissue in its earliest recognizable stage of development. Cells of the primordium are called primordial cells. A primordium is the simplest set of cells capable of triggering growth of the would-be organ and the initial foundation from which an organ is able to grow. In flowering plants, a floral primordium gives rise to a flower.

<span class="mw-page-title-main">Lateral root</span> Plant root

Lateral roots, emerging from the pericycle, extend horizontally from the primary root (radicle) and over time makeup the iconic branching pattern of root systems. They contribute to anchoring the plant securely into the soil, increasing water uptake, and facilitate the extraction of nutrients required for the growth and development of the plant. Lateral roots increase the surface area of a plant's root system and can be found in great abundance in several plant species. In some cases, lateral roots have been found to form symbiotic relationships with rhizobia (bacteria) and mycorrhizae (fungi) found in the soil, to further increase surface area and increase nutrient uptake.

<i>Rhodococcus fascians</i> Species of bacterium

Rhodococcus fascians is a Gram positive bacterial phytopathogen that causes leafy gall disease. R. fascians is the only phytopathogenic member of the genus Rhodococcus; its host range includes both dicotyledonous and monocotyledonous hosts. Because it commonly afflicts tobacco (Nicotiana) plants, it is an agriculturally significant pathogen.

Important structures in plant development are buds, shoots, roots, leaves, and flowers; plants produce these tissues and structures throughout their life from meristems located at the tips of organs, or between mature tissues. Thus, a living plant always has embryonic tissues. By contrast, an animal embryo will very early produce all of the body parts that it will ever have in its life. When the animal is born, it has all its body parts and from that point will only grow larger and more mature. However, both plants and animals pass through a phylotypic stage that evolved independently and that causes a developmental constraint limiting morphological diversification.

<span class="mw-page-title-main">Phototropism</span> Growth of a plant in response to a light stimulus

In biology, phototropism is the growth of an organism in response to a light stimulus. Phototropism is most often observed in plants, but can also occur in other organisms such as fungi. The cells on the plant that are farthest from the light contain a hormone called auxin that reacts when phototropism occurs. This causes the plant to have elongated cells on the furthest side from the light. Phototropism is one of the many plant tropisms, or movements, which respond to external stimuli. Growth towards a light source is called positive phototropism, while growth away from light is called negative phototropism. Negative phototropism is not to be confused with skototropism, which is defined as the growth towards darkness, whereas negative phototropism can refer to either the growth away from a light source or towards the darkness. Most plant shoots exhibit positive phototropism, and rearrange their chloroplasts in the leaves to maximize photosynthetic energy and promote growth. Some vine shoot tips exhibit negative phototropism, which allows them to grow towards dark, solid objects and climb them. The combination of phototropism and gravitropism allow plants to grow in the correct direction.

Plants depend on epigenetic processes for proper function. Epigenetics is defined as "the study of changes in gene function that are mitotically and/or meiotically heritable and that do not entail a change in DNA sequence". The area of study examines protein interactions with DNA and its associated components, including histones and various other modifications such as methylation, which alter the rate or target of transcription. Epi-alleles and epi-mutants, much like their genetic counterparts, describe changes in phenotypes due to epigenetic mechanisms. Epigenetics in plants has attracted scientific enthusiasm because of its importance in agriculture.

LUX or Phytoclock1 (PCL1) is a gene that codes for LUX ARRHYTHMO, a protein necessary for circadian rhythms in Arabidopsis thaliana. LUX protein associates with Early Flowering 3 (ELF3) and Early Flowering 4 (ELF4) to form the Evening Complex (EC), a core component of the Arabidopsis repressilator model of the plant circadian clock. The LUX protein functions as a transcription factor that negatively regulates Pseudo-Response Regulator 9 (PRR9), a core gene of the Midday Complex, another component of the Arabidopsis repressilator model. LUX is also associated with circadian control of hypocotyl growth factor genes PHYTOCHROME INTERACTING FACTOR 4 (PIF4) and PHYTOCHROME INTERACTING FACTOR 5 (PIF5).

CLE peptides are a group of peptides found in plants that are involved with cell signaling. Production is controlled by the CLE genes. Upon binding to a CLE peptide receptor in another cell, a chain reaction of events occurs, which can lead to various physiological and developmental processes. This signaling pathway is conserved in diverse land plants.

Magnetotropism is the movement or plant growth in response to the stimulus provided by the magnetic field in plants around the world. As a natural environmental factor in the Earth, variations of magnetic field level causes many biological effects, including germination rate, flowering time, photosynthesis, biomass accumulation, activation of cryptochrome, and shoot growth.

Hydraulic signals in plants are detected as changes in the organism's water potential that are caused by environmental stress like drought or wounding. The cohesion and tension properties of water allow for these water potential changes to be transmitted throughout the plant.

References

  1. Stirnberg, Petra; Sande, Karin van de; Leyser, H. M. Ottoline (2002-03-01). "MAX1 and MAX2 control shoot lateral branching in Arabidopsis". Development. 129 (5): 1131–1141. ISSN   0950-1991. PMID   11874909.
  2. Hiraoka, Kazuhisa; Yamaguchi, Ayako; Abe, Mitsutomo; Araki, Takashi (2013). "The Florigen Genes FT and TSF Modulate Lateral Shoot Outgrowth in Arabidopsis thaliana". Plant and Cell Physiology. 54 (3): 352–368. doi: 10.1093/pcp/pcs168 . PMID   23220822.
  3. Nicolas, Michael; Cubas, Pilar (2016). "The Role of TCP Transcription Factors in Shaping Flower Structure, Leaf Morphology, and Plant Architecture". Plant Transcription Factors. pp. 249–267. doi:10.1016/b978-0-12-800854-6.00016-6. ISBN   9780128008546.
  4. Breuninger, Holger; Lenhard, Michael (2010). "Control of Tissue and Organ Growth in Plants". Plant Development. Current Topics in Developmental Biology. Vol. 91. pp. 185–220. doi:10.1016/s0070-2153(10)91007-7. ISBN   9780123809100. PMID   20705183.