AgronoBlog – Agriculture Blog One of the important elements of Proroot is its auxins, which are of two types and complement each other, let’s see what this group of phytohormones is about and how to use them for the benefit of crop production.
AUXINS.
Auxin is characteristically synthesized naturally at the stem apex (at or near the terminal meristem) and in young tissues (eg, young leaves) and moves mainly down the stem. It thus tends to form a gradient from the stem apex to the root. Its activities include both stimulation (mainly cell elongation) and growth inhibition, and the same cell or structure can exhibit opposite responses depending on the concentration of Indoleacetic Acid. Furthermore, different tissues respond to very different concentrations: roots are stimulated at concentrations lower than those that stimulate stems, by several orders of magnitude.
As a result of these patterns of activity, the IAA gradient found in plants can produce a wide variety of developmental effects, from the suppression of lateral buds or secondary stems, to the stimulation of stem or root elongation in different parts of the plant. plant. Furthermore, auxin, acting alone or in concert with other hormones, stimulates or inhibits other events, ranging from individual enzymatic reactions to cell division and organ formation. So its effects are many and diverse, and one of the biggest problems in plant physiology is to understand how a small and relatively simple molecule like IAA can have so many different effects and how this apparent confusion of miscellaneous effects is coordinated with control. orderly growth and development.
Types of Auxins
Indoleacetic Acid
The auxin naturally present in plants is 3-indoleacetic acid (IAA). Required during cell elongation and differentiation, IAA uptake by the cell membrane also affects its permeability; IAA produces a general increase in the respiration of plant tissues and promotes the synthesis of messenger RNA and, consequently, of protein-enzymes and structural proteins. The increase in IAA levels inhibits tissue lignification and thus prolongs the period of exposure of non-lignified tissues to the action of the enzymes secreted by the pathogen and that degrade the plant cell wall. The increased respiration rates of infected tissues may also be due to high levels of IAA and, since this auxin affects cell permeability, it is likely to be the factor that increases transpiration in infected plants. Other functions of the IAA are described below:
‐ Inhibits the development of axial buds, giving rise to a phenomenon known as apical dominance.
- Promotes positive phototropism.
- Promotes the development of lateral and adventitious roots.
- Stimulates the development of the fruits.
The influence of this on the buds depends on the angle of growth of the branch since the distribution of this hormone presents a basipetal direction (from the apex downwards). The synthesis and function of auxins in plant diseases has been studied in greater detail in some bacterial diseases of plants. The species Pseudomonas solanacerum, which causes bacterial wilt in Solanaceae, induces a 100-fold increase in IAA levels in diseased plants compared to healthy ones. How increasing levels of IAA contribute to the development of wilting in plants remains to be determined, but the increasing plasticity of cell walls due to high levels of IAA that causes pectin, cellulose, and cell wall proteins are more accessible to attack by their respective enzymes secreted by the pathogen and therefore easier to degrade. Apparently, the increase in IAA levels inhibits tissue lignification and thus prolongs the period of exposure of non-lignified tissues to the action of the enzymes secreted by the pathogen and that degrade the plant cell wall. The increased respiration rates of infected tissues may also be due to high levels of IAA and, since this auxin affects cell permeability, it is likely to be the factor that increases transpiration in infected plants.
Naphthaleneacetic Acid
Growth regulator that, depending on the dose used and time of application, acts on abscission, cell division, etc., in such a way that it can both cause the fall of fruits (thinning) or prevent it, as well as induce the formation of roots in the treated area of various cuttings and cuttings or the flowering of the tropical pineapple. Control regrowth after pruning. It acts as a growth inhibitor at higher concentrations.
Indole Butyric Acid
It is a phytohormone that promotes and accelerates the formation of adventitious roots in plants, its structure is organic, although it can be synthesized. It is frequently used for the propagation of cuttings or cuttings and layers. This type of growth hormone has shown a positive effect on plant development by stimulating the formation of lateral roots. IBA was initially used as a root growth promoter for asexual propagation of ornamental and fruit plants. However, currently some studies have shown that IBA provides direct benefits in the growth of plants that are sown by seed: it promotes the absorption of nutrients, accelerates growth, favors root formation and optimizes metabolic functions.
Tests carried out in foliar and fertigation applications have shown good results in the development of horticultural crops such as tomato and in basic grains in preliminary tests carried out with AIB. In the cultivation of wheat, under greenhouse conditions, they have been shown to favor the development of the root, stem, as well as the absorption of N, P and K in the plant and grain production.
