Girasol definition, an opal that reflects light in a bright luminous glow. See more.
Pheophytin or phaeophytin (abbreviated Pheo) is a chemical compound that serves as the first electron carrier intermediate in the electron transfer pathway of Photosystem II (PS II) in plants, and the photosynthetic reaction center (RC P870) found in purple bacteria.
Auxin (Science: plant biology) a group of plant growth substances (often called phytohormones or plant hormones), the most common example being indole Acetic Acid (IAA), responsible for raising the ph around cells, making the cell wall less rigid and allowing elongation. auxins include indoleacetic acid, phenylacetic acid, and 4-chloro-indoleacetic acid. Commercially, auxins are used to promote root growth, to promote uniform flowering, and to set fruit and prevent premature fruit drop. Synthetic auxins such as 2, 4-D and 2, 4, 5-T have been used as herbicides, broad-leaved weeds like dandelions are much more susceptible to auxins than narrow-leaved plants like grass and cereal crops.