What did made Charles Darwin study gravitropism?

Charles Darwin studied gravitropism, the growth response of plants to gravity, as part of his broader research on plant behavior and adaptation. His interest was sparked by the need to understand how plants orient themselves in their environment, which he explored in his work "The Power of Movement in Plants." Darwin's experiments with seedlings demonstrated how roots grow downward and stems grow upward, contributing to the understanding of plant physiology and evolution. His findings laid the groundwork for modern plant Biology and the study of tropisms.