(a) hormones regulating growth from seed to adulthood
(b) growth regulators synthesised by plants and influencing physiological process
(c) hormones regulating flowering
(d) hormones regulating secondary growth
Growth regulators are organic substances, other than nutrients, which in low concentration regulate growth, differentiation and development by promoting or inhibiting the same. Phytohormones are growth regulators produced naturally in plants and translocated to another region for regulating one or more physiological reactions when present in low concentration. Phytohormone can have at promoting or inhibiting effect on a process.