Effects of Cinnamic Acid on the Root Growth of Cucumber (Cucumis Sativus L.) and Figleaf Gourd (Cucurbita Ficifolia Bouché) Seedlings

The study investigated the effects of cinnamic acid (CA) on root growth and hormone content in cucumber and figleaf gourd seedlings. CA stress reduced root elongation and growth rates in both plants, with a stronger inhibitory effect on cucumber. CA increased root diameter and hair density, with cucumber showing a larger increase in diameter but a smaller increase in hair density compared to figleaf gourd. Under 0.25 mmol/l CA stress, both plants showed increased indole acetic acid (IAA) and ethylene (ET) production, but cucumber had a 16% higher IAA increase and a 51% lower ET increase than figleaf gourd. The study concluded that figleaf gourd is more resistant to CA stress due to its lower IAA increase and higher ET production, which enhances root hair density.