ABSTRACT
Annual crop plants are sown when the environment permits effective germination, emergence, and establishment. The development of plants can be influenced by temperature through influences on the rate of production of nodes and on the triggering of flowering, which can be determined by either accumulated heat units or photoperiod depending on the species or variety. Development also can be influenced by light quality. Plant responses to light quality can explain some of the effects of crop management practices on plants. Optimal development of some plants requires that they experience chilling. Photoperiod-sensitive plants detect and respond to variations in night length through a specific system involving the pigment phytochrome and circadian regulation. Plant responses to light quality can explain some of the effects of crop management practices on plants. Several aspects of plant morphology can vary among plants growing in different growth chambers that have different lighting systems.
