Bio nanaman

• The main advantage of asexual reproduction, in addition to its speed, is that it permits the propagation of advantageous Gentic makeups since the offspring are genetically identical with the parent.
• Sexual reproduction, on the other hand, permits new combination of traits to arise from the contributions of multiple different ancestors.
• Certain plants produce body parts specialized for breakaway and dispersal that are known as Propagules
• In grafting, the plant that is to be asexually propagated is known as the Scion this is attached to the Stock which may be little more than a root. It is important that the two have their Cambium layers in contact with each other.
• The production of Pollen by the seed plants largely circumvents the requirement found in ferns, mosses, and the like for Water as a requirement for fertilization.
• The type of reproduction in which an animal divides into several pieces and then each piece develops into an entire new animal is called Fragmentation
• In metagenesis there is an alternation of Sexual and Asexual Generations
• Parthenogenesis is a type of reproduction in which an unfertilized egg Develops into a new individual
• An individual that can produce both eggs and sperm is described as Hermaphroditic
• A sex cell (either egg or sperm) is properly called a Gamete a fertilized egg is a Zygote
• sporophyte (diploid plant) produces haploid spores by meiosis, which then divide by mitosis and giving rise to the gametophytes (the small male and female haploid plants that produce gametes: sperm and eggs)
• Fertilization results in diploid zygotes, which divide by mitosis and form new sporophytes
• Flowers, the reproductive shoots of the angiosperm sporophyte, are typically composed of four whorls of highly modified leaves called floral organs, which are separated by very short internodes.
• determinate shoots, meaning that they stop growing after the flower and fruit are formed.
• 4 floral organs

  • sepals
  • petals
  • stamens
  • carpels (pistils)
• Floral organs are attached to a part of the stem called the receptacle.
• Stamens and carpels are reproductive organs, whereas sepals and petals are sterile.
• Sepals, which enclose and protect the floral bud before it opens, are usually green and more leaflike in appearance than the other floral organs.
• petals are more brightly colored than sepals and attract the flower to insects and other pollinators.
• stamen consists of a stalk called the filament and a terminal structure called the anther; within the anther are chambers called pollen sacs, in which pollen is produced.
• carpel has an ovary at its base and a long, slender neck called the style. At the top of the style is the sticky structure called the stigma that serves as a landing platform for pollen. Within the ovary are one or more ovules, with the number depending on the species. The term pistil is sometimes used to refer to a single carpel or to group of fused carpels.
• 2 parts of stamen

  • filament
  • anther
• 3 parts of carpel

  • Stigma
  • Style
  • Ovary
• 2 Types of flowers based on the presence of the whorls:

  • complete
  • incomplete
• Complete is a plant biology term that is used to describe a flower that is built with four parts which includes sepals, petals, pistils and stamens
• Incomplete if any of sepals, petals, pistils and stamens which are integral in forming a flower, is missing
• 2 Types of flowers based on the presence of the reproductive whorls

  • perfect/bisexual
  • imoerfect/unisexual
• 2 parts of imperfect/unisexual flowers

  • Staminate flower (male)
  • Carpellate/pistillate flower (female)
• Perfect/Bisexual is one in which both male and female reproductive

  structures are present. Both androecium (whorl of stamens) and gynoecium

  (whorl of carpels or pistil) are located on the same flower
• Imperfect/Unisexual flower that does not have both male and female structures.
• Anthers and ovules bear sporangia, structures where spores are produced by meiosis and gametophytes develop.
• In angiosperms, pollination is the transfer of pollen from an anther to a stigma.
• If pollination is successful, a pollen grain produces a structure called a pollen tube, which grows and digests its way down into the ovary via the style and discharges sperm in the vicinity of the embryo sac, resulting in fertilization of the egg.
• Fruits, which disperse by dropping to the ground or being carried by wind or animals, help spread seeds some distance from their source plants.
• Double fertilization After landing on a receptive stigma, a pollen grain absorbs moisture and germinates; that is, it produces a pollen tube that extends down between the cells of the style toward the ovary.
• From ovule to seed After double fertilization, each ovule develops into a seed, and the ovary develops into a fruit enclosing the seed(s). As the embryo develops from the zygote, the seed stockpiles proteins, oils, and starch to varying extents, depending on the species. This is why seeds are such major sugar sinks. Initially, these nutrients are stored in the endosperm, but later in seed development in many species, the storage function of the endosperm is more or less taken over by the swelling cotyledons of the embryo (Campbell & Reece).
• From Ovary to Fruit

  While the seeds are developing from ovules, the ovary of the flower is developing into a fruit, which protects the enclosed seeds and, when mature, aids in their dispersal by wind or animals. Fertilization triggers hormonal changes that cause the ovary to begin its transformation into a fruit. If the flower has not been pollinated, fruit usually does not develop, and the entire flower withers and falls away.

  During fruit development, the ovary wall becomes the pericarp, the thickened wall of the fruit. As the ovary grows, the other parts of the flower wither and are shed
• two principal modes

  • asexual (without sex)
  • sexual (fusion of gametes)
• Asexual reproduction is the creation of new individuals whose genes all come from one parent without the fusion of egg and sperm.
• Sexual reproduction is the creation of offspring by the fusion of haploid gametes to form a zygote (fertilized egg), which is diploid.