carpel

Examples of carpel in the following topics:

• Angiosperm Flowers

  • The sexual organs (carpels and stamens) are located at the center of the flower.
  • Carpels may be singular, multiple, or fused.
  • Multiple fused carpels comprise a pistil.
  • The flower shown has only one carpel, but some flowers have a cluster of carpels.
  • Together, all the carpels make up the gynoecium.

• Development of Fruit and Fruit Types

  • If the fruit develops from a single carpel or fused carpels of a single ovary, it is known as a simple fruit, as seen in nuts and beans.
  • An aggregate fruit is one that develops from numerous carpels that are all in the same flower; the mature carpels fuse together to form the entire fruit, as seen in the raspberry.
  • Aggregate fruits, like raspberries, form from many carpels that fuse together.

• Sexual Reproduction in Angiosperms

  • The carpel is the individual unit of the gynoecium and has a stigma, style, and ovary.
  • A flower may have one or multiple carpels.
  • There are two types of incomplete flowers: staminate flowers contain only an androecium; and carpellate flowers have only a gynoecium .
  • The corn plant has both staminate (male) and carpellate (female) flowers.
  • Carpellate flower are clustered in the immature ears.

• Genetic Control of Flowers

  • The ABC model of flower development was first developed to describe the collection of genetic mechanisms that establish floral organ identity in the Rosids and the Asterids; both species have four verticils (sepals, petals, stamens and carpels), which are defined by the differential expression of a number of homeotic genes present in each verticil.
  • In the third whorl, B and C genes interact to form stamens and in the center of the flower C-genes alone give rise to carpels.
  • In the third whorl the lack of B function but presence of C-function mimics the fourth whorl, leading to the formation of carpels also in the third whorl .
  • Class A genes (blue) affect sepals and petals, class B genes (yellow) affect petals and stamens, class C genes (red) affect stamens and carpels.

• The Life Cycle of an Angiosperm

  • The ovule, sheltered within the ovary of the carpel, contains the megasporangium protected by two layers of integuments and the ovary wall.
  • Anthers and carpels are structures that shelter the actual gametophytes: the pollen grain and embryo sac.

• Herbivory and Pollination

  • Pollination (the transfer of pollen to a carpel) is mainly carried out by wind and animals; therefore, angiosperms have evolved numerous adaptations to capture the wind or attract specific classes of animals.

• Pollination and Fertilization

  • Self-pollination occurs in flowers where the stamen and carpel mature at the same time and are positioned so that the pollen can land on the flower's stigma.