How Does Gibberellin Affect The Growth Of Plants?

Gibberellins are plant growth regulators that facilitate cell elongation, help plants grow taller, and play major roles in germination. They are hormones that control growth and various plant developmental processes. Early studies revealed the large chemodiversity of gibberellins in plants, which can form local accumulation maxima in the root elongation zone and hypocotyl, which correlate with cellular growth. Gibberellins play fundamental roles in almost every aspect of plant growth and development, including cell elongation, leaf expansion, leaf senescence, seed germination, and leafy head formation.

Gibberellin action relies on the degradation of DELLA repressors, which are essential for various plant developmental processes. Some of the most characteristic effects of gibberellins on shoot growth include increased inter-node extension, increased leaf-growth, and enhanced apical dominance. These genes acidize and soften cell walls, benefiting stem cell elongation and proliferation. They positively regulate cell division and elongation, stimulating hypocotyl and stem growth and having a positive effect on leaf size and root meristem size.

Gibberellin and antigibberellin agents increase the weight of dry matter in plants, raise net photosynthetic productivity, and optimize productivity of plants. They can stimulate long day-plants to flower, even if they are kept in short days, while GA is without effect on short-day plants. Gibberellins, alone among the hormones, have been shown to have a definitive effect on shoot and stolon growth and inhibit tuberization. The most characteristic effects of GA on shoot growth are increased inter-node extension, increased leaf-growth, and enhanced apical dominance.

How do gibberellins help plant growers?

Gibberellins are plant hormones that promote flowering, resulting in more profitable flowers and larger specimens. They are used in seedless fruit production, such as seedless grapes, which are sprayed with gibberellin to increase their size. Hormones, such as ethene, are used in the food industry to control ripening during storage, transport, or display in shops. Ethene is a gas that speeds up ripening in fruits, such as bananas, which are picked when they are green and unripened.

The effect of ethene on bananas is visible when they are kept in a bowl with other fruits, causing them to ripen quickly. Overall, gibberellins and other hormones play crucial roles in the production and marketing of seedless fruits.

Does gibberellins inhibit plant growth?

Plant growth regulators (PGRs), including gibberellins, have gained interest in agriculture scientists due to their role in promoting plant growth and developmental processes. Gibberellins, first discovered in the 1930s, are a large family of hormones found in higher plants that promote various aspects of plant growth and development. However, only a few gibberellins, such as GA1, GA3, GA4, and GA7, have intrinsic biological activity in higher plants.

GA4 and GA7 have gained attention due to their special effects on plants. GA 4+7 has been suggested to induce fruit set and increase fruit size in cucumber, pear, and apple fruits. GA 4+7-treated fruits accumulate more sucrose and fewer organic acids compared to pollinated fruit, making it an important agricultural remedy in horticultural crops. However, the application of GA 4+7 in cereal crops is limited, and the effect of exogenous GA 4+7 on maize grain filling and its physiological mechanism has not been determined.

Reactive oxygen species (ROS) are continually produced in plants, which can trigger cellular responses. Plants have evolved an enzymatic and nonenzymatic antioxidant defense mechanism to effectively scavenge ROS and maintain a proper balance within plants. Enzymatic antioxidants include superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT). However, senescence and environmental stresses can disrupt this balance, leading to lipid peroxidation, chlorophyll degradation, and loss of cell membrane integrity.

Previous studies have indicated that the potential of GA 4+7 to control grain filling in maize is limited, and its possible effects on hormone change and antioxidants have not been investigated in detail. This study investigates the effects of shank and silk treatments with different concentrations of GA 4+7 on grain-filling rate, hormonal changes, and antioxidant changes, with the aim of achieving higher grain yield in high-density maize.

What is the physiological role of gibberellins in plants?

Gibberellins have a marked effect on the elongation of stems and leaf sheaths in intact plants. Conversely, the absence of gibberellins results in the shortening of internodes and a reduction in overall height, as observed in a range of plant species, including peas, beans, cucumbers, lettuce, peppers, and cabbage.

Does gibberellin affect flowering?

Gibberellins (GAs) affect flowering in a species-dependent manner, promoting flowering in long-day and biennial plants and inhibiting it in fruit trees. The mechanism by which GAs promote flowering in Arabidopsis is not fully understood, but there is increasing evidence that they may act through multiple pathways. In citrus, GA treatment during the flowering induction period reduces the number of flowers, and the mechanism of flowering inhibition is not clear.

However, bud metabolic and regulatory pathways are expected to be altered upon GA treatment. The study investigated the effect of GA treatments on global gene expression in the bud during the induction period and the expression of key flowering genes. About 2000 unigenes showed altered expression, with about 300 showing at least a two-fold change. Changes in flavonoids and trehalose metabolic pathways were validated, and other altered pathways, such as cell-wall components, were discussed in light of GA’s inhibition of flowering. GA treatment resulted in reduced mRNA levels of FT, AP1, and a few flower-organ-identity genes.

How does gibberellic acid affect plant growth?

Gibberellins (GAs) are essential for cell division and expansion in response to light or dark. They regulate flower initiation in some LD and biennial species and inhibit flowering in some perennials. GAs are essential for male and female fertility but not for the specification and differentiation of floral organs. Studies have shown that GAs regulate flower initiation in some sunflower plants, fluctuation and localization of endogenous gibberellins in rice, and the effect of the Le/le gene difference on endogenous gibberellin-like substances in Pisum.

How does gibberellin actually work?

Gibberellins, produced in higher plants when exposed to cold temperatures, stimulate cell elongation, breaking and budding, seedless fruits, and seed germination. They act as a chemical messenger by breaking the seed’s dormancy and binding to a receptor. Calcium activates the protein calmodulin, which binds to DNA, producing an enzyme to stimulate embryo growth. Gibberellins are usually synthesized from the methylerythritol phosphate (MEP) pathway in higher plants, which produces bioactive GA from trans-geranylgeranyl diphosphate (GGDP).

The MEP pathway involves eight steps: GGDP is converted to ent-copalyl diphosphate (ent-CDP), ent-kaurene, ent-kaurenol, ent-kaurenal, ent-kaurenoic acid, ent-7a-hydroxykaurenoic acid, GA12-aldehyde, GA12-aldehyde, and GA4 by oxidations on C-20 and C-3, which are accomplished by two soluble ODDs: GA 20-oxidase and GA 3-oxidase. This process helps to break the seed’s dormancy and stimulate growth in the embryo.

What are the two main functions of gibberellins?

Gibberellins are essential plant growth regulators that facilitate a number of crucial processes, including cell elongation, plant growth, germination, stem elongation, fruit ripening, and flowering.

What is the 3 effect of gibberellins on plants?

Gibberellins are plant growth regulators that aid in cell elongation, plant growth, germination, stem elongation, fruit ripening, and flowering. Farmers use gibberellins to accelerate seed germination and stimulate cell and stem elongation, thereby increasing crop production. These regulators are formed in plastids via the terpenoid pathway and transformed in the endoplasmic reticulum and cytosol.

What are three functions of gibberellins in a standard plant?

Gibberellins (GAs) are crucial in plant growth and development, particularly in seed germination, stem elongation, leaf expansion, and flowering. They are involved in various stages of plant growth and development, including shopping cart, contact and support, terms and conditions, privacy policy, and cookies. Copyright © 2024 Elsevier B. V., its licensors, and contributors. All rights reserved, including text and data mining, AI training, and similar technologies.

What is the role of gibberellins in plant development and crop yield?

Gibberellins (GAs) are tetracyclic diterpenoid phytohormones that regulate a multitude of processes inherent to plant development, including seed germination, stem elongation, leaf expansion, pollen maturation, and the development of flowers, fruits, and seeds.

What are the effects of gibberellins on plant growth?

The impact of GA on shoot growth is considerable, resulting in increased inter-node extension, leaf growth, and apical dominance. Nevertheless, in certain plant species, GA treatment may not elicit root growth stimulation, although some root sections do respond.