In this type the hormone can pass through the plasma membrane into the cytoplasm. Here it binds with its receptor molecule to form a hormone-receptor complex. In the second type , a peptide hormone binds to a receptor protein on the target cell. One thing plant hormones specifically control is gene expression. It is important to point out that the exact mechanisms by which hormones regulate gene expression are poorly understood.
Gene expression is part of a large amplification process.
It is likely that gene regulation is affected by certain enzymes after initial hormone binding. Genes may be altered by secondary and tertiary messengers of a cellular cascade as well. Summarize This table shows five clasical plant hormones, site of biosynthesis, and their effects. The effect of plant growth substances on pea plant Safe use of plant growth substances.