Plant Hormones (Phytohormones)
Plant hormones or phytohormones are small, simple chemical molecules, which are present in low concentration in plants and regulate growth, differentiation and development.
Two Categories of Phytohormones:
① Plant growth promoters: Examples are auxins, gibberellins and cytokinins.
② Plant growth inhibitors: Examples are abscisic acid, ethylene.
All about Auxins
⒈ Auxins are weakly acidic growth hormones.
⒉ Darwin (1880) was first to find about Auxins in the tip of canary grass.
⒊ These hormones are found in shoot apex, leaf Primordia and developing seeds.