The natural plant hormones were first isolated froma)Cotton fruits, spinach leaves and rice plantb)Avena coleoptiles, spinach leaves and fungus Gibberellac)Human urine and corn germ oild)Human urine and rice plantCorrect answer is option 'C'. Can you explain this answer?

Question

Answer

Auxins were first isolated from human urine. The term auxin is applied to the indole-3-acetic acid (IAA), and to other natural and synthetic compounds having certain growth-regulating properties.

Cytokinins have specific effects on cytokinesis and were discovered as kinetin from the autoclaved herring sperm DNA.
Kinetin does not occur naturally in plants. Search for natural substances with cytokinin-like activities led to the isolation of zeatin from corn kernels (corn germ oil) and coconut milk.

Hence option C is correct.

Answer

First isolated from human urine, auxin is a term applied to natural and synthetic compounds that have growth regulating properties. Plants produce natural auxins such as Indole-3-acetic acid (IAA) and Indole butyric acid (IBA).

Answer

The first naturally plant hormone that is auxin was isolated by kogl and haagen- Smit in 1931 from human urine

Answer

Auxins were isolated from human urine.
Gibberellins were isolated from rice plants infected with GIBBERILLA FUJICORAI a deuteromycetes member

Answer

Answer

C.

Answer

Answer:

The correct answer is option 'C': Human urine and corn germ oil.

Explanation:

Plant hormones, also known as phytohormones, are naturally occurring chemical substances that regulate various physiological processes in plants. They are responsible for controlling growth, development, and responses to environmental stimuli.

The isolation of plant hormones was a significant breakthrough in plant physiology research. The initial discovery and isolation of plant hormones were made by several scientists, and their experiments led to the identification of different types of plant hormones.

Discovery of Plant Hormones:

Plant hormones were first isolated and identified in the early 20th century. Here is a brief overview of the discoveries made by different scientists:

1. Auxins: The discovery of auxins can be attributed to the experiments conducted by Frits Went in the 1920s. Went observed that the tips of oat coleoptiles (embryonic shoots) produced a substance that stimulated growth in other parts of the plant. He named this substance 'auxin.' Later, auxin was also found in spinach leaves.

2. Gibberellins: The discovery of gibberellins can be credited to the research carried out by Japanese scientists, including Teijiro Yabuta and Eiichi Kurosawa, in the 1920s. They were studying a fungal disease called 'foolish seedling disease' that affected rice plants. They isolated a compound from the fungus Gibberella fujikuroi, which was responsible for the elongation of infected rice plants. This compound was later identified as a plant hormone and named 'gibberellin.'

3. Cytokinins: In the 1950s, a team of researchers led by Folke Skoog and Carl Miller discovered cytokinins. They observed that adding a nutrient solution extracted from corn germ oil or coconut milk to cultured plant tissues stimulated cell division and growth. They isolated the active compound responsible for this effect and named it 'kinetin.' Later, other cytokinins were also discovered.

4. Abscisic Acid: Abscisic acid was discovered in the 1960s by Frederick Addicott and his team. They found that a compound extracted from human urine had a significant effect on plant growth. This compound, which they named 'abscisic acid,' was later identified as a plant hormone involved in the regulation of various physiological processes, including seed dormancy and stress responses.

Conclusion:

In conclusion, the natural plant hormones were first isolated from human urine and corn germ oil. The discoveries of auxins, gibberellins, cytokinins, and abscisic acid have played a crucial role in our understanding of plant physiology and have paved the way for further research in this field.

Answer

Clearly written in NCERT..

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