The simplest method to measure population density is to visually count the number of organisms in a population in a given habitat.

TLS Online TPP Program

#Id: 4585

#Unit 6. System Physiology – Plant

Typical photoreversible responses induced by phytochrome in variety of higher and lower plants

TLS Online TPP Program

#Id: 4586

#Unit 6. System Physiology – Plant

Corn and bean seedlings grown in the light or the dark

TLS Online TPP Program

#Id: 4587

#Unit 6. System Physiology – Plant

Developmental changes by light (photomorphogenesis) transformation from the etiolated to the green state.

a. A decrease in the rate of stem elongation

b. The beginning of apical-hook straightening

c. The initiation of the synthesis of pigments

TLS Online TPP Program

#Id: 4638

#Unit 6. System Physiology – Plant

Seedlings grown in the dark display an etiolated growth pattern:

a) yellow unexpanded cotyledons

b) apical hook

c) Long hypocotyl

TLS Online TPP Program

#Id: 4947

#Unit 6. System Physiology – Plant

Expression of the other phytochrome types (B to E in angiosperms) is independent of light and both Pr and Pfr forms are stable.

TLS Online TPP Program

#Id: 4948

#Unit 6. System Physiology – Plant

Phytochrome B (PhyB) is probably the photoreceptor involved in shade detection and avoidance. This response allows many species to greatly increase their stem extension rate when they become shaded by competitors.