Plant hormone responsible for growth of stem

Almost all plants can photosynthesize, and photosynthesis is key to these plants' survival: it lets them make sugar molecules that serve as fuel and building materials. But plants respond to light—sometimes, to specific wavelengths of light—in other ways as well. These non-photosynthesis-related responses allow plants to adjust to their environment and optimize growth. For instance, some types of seeds will germinate only when they receive a sufficient amount of light—along with other cues. Other plants have ways to detect if they are in the shade of neighboring plants based on the quality of light they receive. They can increase their upward growth to outcompete their neighbors and get a bigger share of sunshine. Plant responses to light depend, logically enough, on the plant’s ability to sense light. Light sensing in plants involves special molecules called photoreceptors, which are made up of a protein linked to a light-absorbing pigment called a chromophore. When the chromophore absorbs light, it causes a change in the shape of the protein, altering its activity and starting a signaling pathway. The signaling pathway results in a response to the light cue, such as a change in gene expression, growth, or hormone production. Shoots, or above-ground parts of plants, generally display positive phototropism—they bend toward the light. This response helps the green parts of the plant get closer to a source of light energy, which can then be used for photosynthesis. Roots, on...

Abstract During plant embryogenesis, the apical–basal axis is established and both the shoot apical meristem (SAM) and the root apical meristem (RAM) are formed. In both meristems, there are slowly dividing cells which control the differentiation of their surrounding cells called the organizing centre (OC) and the quiescent centre (QC) in the shoot and root, respectively. These centres with their surrounding initial cells form a ‘stem cell niche’. The initial cells eventually differentiate into various plant tissues, giving rise to plant organs such as lateral shoots, flowers, leaves, and lateral roots. Plant hormones are important factors involved in the balance between cell division and differentiation such that plant growth and development are tightly controlled in space and time. No single hormone acts by itself in regulating the meristematic activity in the root meristem. Division and differentiation are controlled by interactions between several hormones. Intensive research on plant stem cells has focused on how cell division is regulated to form specific plant organs and tissues, how differentiation is controlled, and how stem cell fate is coordinated. In this review, recent knowledge pertaining to the role of plant hormones in maintaining root stem cells including the QC is summarized and discussed. Furthermore, we suggest diverse approaches to answering the main question of how root stem cells are regulated and maintained by plant hormones. Introduction A root is ...

\( \newcommand\) • • • • • • • Growth Responses A plant’s sensory response to external stimuli relies on hormones, which are simply chemical messengers. Plant hormones affect all aspects of plant life, from flowering to fruit setting and maturation, and from phototropism to leaf fall. Potentially, every cell in a plant can produce plant hormones. The hormones can act in their cell of origin or be transported to other portions of the plant body, with many plant responses involving the synergistic or antagonistic interaction of two or more hormones. In contrast, animal hormones are produced in specific glands and transported to a distant site for action, acting alone. Plant hormones are a group of unrelated chemical substances that affect plant morphogenesis. Five major plant hormones are traditionally described: auxins, cytokinins, gibberellins, ethylene, and abscisic acid. In addition, other nutrients and environmental conditions can be characterized as growth factors. The first three plant hormones largely affect plant growth, as described below. Auxins The term auxin is derived from the Greek word auxein, which means “to grow. ” Auxins are the main hormones responsible for cell elongation in phototropism and gravitropism. They also control the differentiation of meristem into vascular tissue and promote leaf development and arrangement. While many synthetic auxins are used as herbicides, indole acetic acid (IAA) is the only naturally-occurring auxin that shows physiologi...

Use of plant hormones There are many types of plant hormones . They are used in agriculture and horticulture to have a specific effect. Auxins were the first class of plant hormones to be discovered. Their main function is to help plants grow and auxin stimulates plant cells to elongate . The apical meristem of a plant is one of the main places where auxin is produced. The apical meristem is also the location that all other parts of a plant grow from - the stem, leaves, and flowers. Auxins are one specific group of hormones that are used: • as weed killers • as rooting powders Weed killers Selective weed killers kill some plants, but not others. This can be useful for getting rid of dandelions in a lawn without killing the grass. The selective weed killer contains a growth hormone that causes the weeds to grow too quickly and die. Because the weeds have broader leaves, the weed killer is absorbed in larger quantities by the weeds than it is by the grass. Selective weed killers can reduce biodiversity within treated areas due to specific plants being killed. Rooting powder contains plant hormones to promote growth. Plant cuttings can be dipped in hormone rooting powder before planting. Synthetic plant hormones are used to control plant growth. For example, rooting powder contains growth hormones that make stem cuttings develop roots quickly. Other plant hormones Gibberellins are a group of plant hormones responsible for growth and development. They are important for initiat...

Plant Hormones Definition Plant hormones are chemicals plants use for communication, coordination, and development between their many cells. Like animals, plants rely on these chemical signals to direct the expression of DNA and the operations of the cell. Plant hormones are natural substances which control many aspects of plant development. They control everything from the length between nodes on the branches to the programmed death, or senescence seen in many annual plants. There are 5 major classes of plant hormone, each which controls various aspects of plant development. There are also several other recently recognized plant hormones. Remember that these are general categories, and that individual species may have developed novel uses for various hormones. Types of Plant Hormones Abscisic Acid The original name of abscisic acid was dormin, because the plant hormones are heavily involved in the dormancy process. Today, these plant hormones have two main recognized functions in plants. First, they regulate the process of seed development. This helps transform the embryo into a fully-fledged seedling. Second, these plant hormones play a crucial role in the plant’s response to temperature and water loss. As the temperature increases, more water evaporates out of the stoma, little holes in the leaves. As the temperature reaches a point which starts dramatic water loss, abscisic acid is produced and released into the leaves. This causes the stoma to close, and the water is ...