Plant hormones, also known as phytohormones, regulate plant growth and development. Among the common plant hormones, one exists primarily in a gaseous state.
The options provided are:
Ethylene is the only plant hormone that is a gas at room temperature and atmospheric pressure. It is involved in processes like fruit ripening, senescence, and abscission.
Auxins, Gibberellins, and Cytokinins are typically found and function in non-gaseous forms (e.g., liquids or solids). Therefore, Ethylene is the correct choice for the gaseous hormone.
| List-I | List-II |
| Electronic Configuration | First Ionisation energy (kJ mol$^{-1}$) |
| (A). ns$^2$ | (I). 2100 |
| (B). ns$^2$np$^1$ | (II). 1400 |
| (C). ns$^2$np$^3$ | (III). 800 |
| (D). ns$^2$np$^6$ | (IV). 900 |
| List-I | List-II |
| Spectroscopy | Property |
| (A). Raman | (I). Polarizability |
| (B). FTIR | (II). Dipole Moment |
| (C). UV-Visible | (III). Absorbance |
| (D). NMR | (IV). Spin |