Plant Growth

Meristems

What environmental factors affect plant growth?

Environmental Factors… light nutrients temperature soil What was the factor that you studied in your lab?

Tropisms change in the growth of a plant in response to a stimulus

Phototropism

Gravitropism

Thigmotropism

Plant Growth Regulators

Auxins promote cell elongation occurs on “dark side” causing phototropism

Gibberellins action variable promotes cell division & elongation plays role in flowering & fruit production gibberellin spray induces fruit production & elongates fruit stems in grapes

Cytokinins promote cell division found in growing tissues such as meristems, young leaves, growing seeds slow cell aging sprayed on mushrooms & lettuce to prevent spoiling

Ethylene gas that is produced at various stages of plant growth “plant stress hormone” also stimulates fruit ripening, and many other developmental stages ethylene levels controlled so that fruit is ripe when sold at the store

Abscisic Acid (ABA) inhibits growth maintains dormancy in seeds and leaf buds levels rise in response to temperature & light changes (e.g., seasonal change) sometimes used on plants that are being shipped