Purple Blossoms

Flowers are the reproductive, seed-producing structures of angiosperms. Typically, flowers consist of sepals, petals, stamens, and carpels. Sepals and petals are the vegetative flower organs. Stamens and carpels are the reproductive organs.

Plant morphogenesis—the development of a plant’s form and structure—involves several overlapping developmental processes, including growth and cell differentiation. Precursor cells differentiate into specific cell types, which are organized into the tissues and organ systems that make up the functional plant.

The circadian—or biological—clock is an intrinsic, timekeeping, molecular mechanism that allows plants to coordinate physiological activities over 24-hour cycles called circadian rhythms. Photoperiodism is a collective term for the biological responses of plants to variations in the relative lengths of dark and light periods. The period of light-exposure is called the photoperiod.

Alleles are different forms of the same gene. Humans and other diploid organisms inherit two alleles of every gene, one from each parent.

In order to produce glucose, plants need to capture sufficient light energy. Many modern plants have evolved leaves specialized for light acquisition. Leaves can be only millimeters in width or tens of meters wide, depending on the environment. Due to competition for sunlight, evolution has driven the development of increasingly larger leaves and taller plants, to avoid shading by their neighbors, along with the elaboration of root architecture and mechanisms to transport water and...

To determine whether traits are inherited together or separately, Gregor Mendel crossed pea plants that differed in two traits. These parental plants were homozygous for both traits but displayed different phenotypes. The first generation of offspring were all dihybrids, heterozygotes exhibiting the two dominant phenotypes. When self-fertilized, the dihybrids consistently produced progeny with a 9:3:3:1 ratio of four possible phenotype combinations. This ratio suggested that inheriting one...