KNOX transcription factors activate the cytokinin biosynthetic gene ISOPENTENYL TRANSFERASE7 -IPT7

TLS Online TPP Program

#Id: 9823

#Unit 6. System Physiology – Plant

HIRs require prolonged or continuous exposure to light of relatively high irradiance, and the response is proportional to the irradiance

TLS Online TPP Program

#Id: 9824

#Unit 6. System Physiology – Plant

Plants that increase stem extension in response to shading are said to exhibit a shade avoidance response.

As shading increases, the R:FR ratio decreases. Shade means far red light

TLS Online TPP Program

#Id: 9825

#Unit 6. System Physiology – Plant

phyB–phyE, appear mostly light-stable in the plant and function primarily in the regulation of LFRs and of shade avoidance involving changes in the R:FR ratio.

TLS Online TPP Program

#Id: 9826

#Unit 6. System Physiology – Plant

phyA is rapidly degraded as Pfr and controls plant responses to VLFRs and the far-red HIRs.

TLS Online TPP Program

#Id: 9827

#Unit 6. System Physiology – Plant

Mutants lacking phyA also failed to germinate in response to millisecond pulses of light, but showed a normal response to red light in the low-fluence range. Means pfr primarily receives VLFR

TLS Online TPP Program

#Id: 9828

#Unit 6. System Physiology – Plant

phyC, phyD, and phyE appear to play roles that are for the most part redundant with those of phyA and phyB. Whereas phyB appears to be involved in regulating all stages of development