Ch 11 Growth and development (11.5-11.6)

Length of day (night) directly related to onset of flowering

Will not flower unless day length is shorter than a critical period

Asters, poinsettias, ragweed, sorghums, strawberries

Will not flower unless periods of light are longer than a critical period

Beets, larkspur, lettuce, potatoes, spinach, wheat

Will not flower if days too short, or too long

Several grasses

Will flower under any day-length, provided there is minimum amount of light necessary for normal growth

Tropical plants, beans, carnations, cotton, roses, tomatoes

What are the vegetative activities affected by phototropisms