INDOLE-3-ACETIC ACID IN CHICK EMBRYOS

Area of Science:

• Developmental biology
• Plant hormone research
• Biochemistry

Background:

• Auxins, a class of plant growth hormones, play critical roles in plant development.
• Indole-3-acetic acid (IAA) is the most common and potent natural auxin.
• The presence and role of plant hormones in non-plant organisms are not fully understood.

Purpose of the Study:

• To investigate the occurrence and quantify indole-3-acetic acid (IAA) in developing chick embryos.
• To determine how IAA levels change during embryonic development.
• To compare IAA levels in incubated versus unincubated eggs.

Main Methods:

• Paper chromatography and the Avena curvature test were used to detect auxin activity.
• Combined gas chromatography-mass spectrometry (GC-MS) confirmed the identity of the substance as IAA.
• Quantification of IAA in embryo tissue and whole eggs at different developmental stages.

Main Results:

• A substance with auxin activity, identical to IAA, was identified in developing chick embryos.
• The concentration of IAA per unit weight of embryo remained relatively constant during development.
• The total amount of IAA per embryo increased with embryonic growth.
• Incubated eggs (9 days at 37°C) contained significantly more IAA than unincubated eggs.

Conclusions:

• Developing chick embryos contain indole-3-acetic acid (IAA), suggesting a conserved biological role or uptake mechanism.
• Embryonic development leads to an increase in total IAA, correlating with embryo growth.
• Egg incubation enhances IAA levels, indicating potential synthesis or accumulation during incubation.