In chloroplasts of leaves.

Chlorophyll a is the primary photosynthetic pigment that absorbs light in the blue and red regions of the electromagnetic spectrum.

Plant cell sap is slightly acidic due to organic acids like malic acid and citric acid, maintaining pH between 4-6.

Magnesium (Mg) is the central atom in the chlorophyll molecule, forming a coordinate bond with the porphyrin ring.

Auxin causes differential elongation of cells on the shaded side, resulting in phototropic response towards light.

In C4 photosynthesis, CO2 combines with PEP (3-carbon) to form oxaloacetate (4-carbon compound) via the enzyme PEP carboxylase.

Root pressure is measured using a manometer connected to the cut end of a plant stem, showing the positive pressure generated by roots.

During stomatal opening, potassium ions (K+) actively accumulate in guard cells, increasing osmotic potential and causing water influx.

Abscisic acid (ABA) accumulates during water stress and environmental changes, promoting abscission layer formation and leaf fall.

High auxin to low cytokinin ratio promotes callus formation, while the ratios determine the type of organogenesis.