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 Photos depict a variety of nuts in their shells, an apple, raspberries and a pineapple.
There are four main types of fruits. Simple fruits, such as these nuts, are derived from a single ovary. Aggregate fruits, like raspberries, form from many carpels that fuse together. Multiple fruits, such as pineapple, form from a cluster of flowers called an inflorescence. Accessory fruit, like the apple, are formed from a part of the plant other than the ovary. (credit "nuts": modification of work by Petr Kratochvil; credit "raspberries": modification of work by Cory Zanker; credit "pineapple": modification of work by Howie Le; credit "apple": modification of work by Paolo Neo)

Fruits generally have three parts: the exocarp    (the outermost skin or covering), the mesocarp    (middle part of the fruit), and the endocarp    (the inner part of the fruit). Together, all three are known as the pericarp    . The mesocarp is usually the fleshy, edible part of the fruit; however, in some fruits, such as the almond, the endocarp is the edible part. In many fruits, two or all three of the layers are fused, and are indistinguishable at maturity. Fruits can be dry or fleshy. Furthermore, fruits can be divided into dehiscent or indehiscent types. Dehiscent fruits, such as peas, readily release their seeds, while indehiscent fruits, like peaches, rely on decay to release their seeds.

Fruit and seed dispersal

The fruit has a single purpose: seed dispersal. Seeds contained within fruits need to be dispersed far from the mother plant, so they may find favorable and less competitive conditions in which to germinate and grow.

Some fruit have built-in mechanisms so they can disperse by themselves, whereas others require the help of agents like wind, water, and animals ( [link] ). Modifications in seed structure, composition, and size help in dispersal. Wind-dispersed fruit are lightweight and may have wing-like appendages that allow them to be carried by the wind. Some have a parachute-like structure to keep them afloat. Some fruits—for example, the dandelion—have hairy, weightless structures that are suited to dispersal by wind.

Seeds dispersed by water are contained in light and buoyant fruit, giving them the ability to float. Coconuts are well known for their ability to float on water to reach land where they can germinate. Similarly, willow and silver birches produce lightweight fruit that can float on water.

Animals and birds eat fruits, and the seeds that are not digested are excreted in their droppings some distance away. Some animals, like squirrels, bury seed-containing fruits for later use; if the squirrel does not find its stash of fruit, and if conditions are favorable, the seeds germinate. Some fruits, like the cocklebur, have hooks or sticky structures that stick to an animal's coat and are then transported to another place. Humans also play a big role in dispersing seeds when they carry fruits to new places and throw away the inedible part that contains the seeds.

All of the above mechanisms allow for seeds to be dispersed through space, much like an animal’s offspring can move to a new location. Seed dormancy, which was described earlier, allows plants to disperse their progeny through time: something animals cannot do. Dormant seeds can wait months, years, or even decades for the proper conditions for germination and propagation of the species.

 Part A shows a dandelion flower that has seeded.  Part B shows a coconut floating in water.  Part c shows two acorns.
Fruits and seeds are dispersed by various means. (a) Dandelion seeds are dispersed by wind, the (b) coconut seed is dispersed by water, and the (c) acorn is dispersed by animals that cache and then forget it. (credit a: modification of work by "Rosendahl"/Flickr; credit b: modification of work by Shine Oa; credit c: modification of work by Paolo Neo)

Section summary

For fertilization to occur in angiosperms, pollen has to be transferred to the stigma of a flower: a process known as pollination. Gymnosperm pollination involves the transfer of pollen from a male cone to a female cone. When the pollen of the flower is transferred to the stigma of the same flower, it is called self-pollination. Cross-pollination occurs when pollen is transferred from one flower to another flower on the same plant, or another plant. Cross-pollination requires pollinating agents such as water, wind, or animals, and increases genetic diversity. After the pollen lands on the stigma, the tube cell gives rise to the pollen tube, through which the generative nucleus migrates. The pollen tube gains entry through the micropyle on the ovule sac. The generative cell divides to form two sperm cells: one fuses with the egg to form the diploid zygote, and the other fuses with the polar nuclei to form the endosperm, which is triploid in nature. This is known as double fertilization. After fertilization, the zygote divides to form the embryo and the fertilized ovule forms the seed. The walls of the ovary form the fruit in which the seeds develop. The seed, when mature, will germinate under favorable conditions and give rise to the diploid sporophyte.

Art connections

[link] What is the function of the cotyledon?

  1. It develops into the root.
  2. It provides nutrition for the embryo.
  3. It forms the embryo.
  4. It protects the embryo.

[link] B

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Questions & Answers

what is micro-organism
Jackson Reply
what is the hypothesis
hypothesis is a proposed explanation for a phenomenon
hypothesis is raw materials
what is biology
what does mean stigma
Amira Reply
what is the full of the MOST dangerous disease in the world where one stops sleeping and just dies :Hint ; FFI
God Reply
fatal familial insomnia which affects the thalamus
there are other dangerous diseases like CAD i.e coronary artery disease
what is matter
Thomas Reply
it is any thing that has weight and occupies space
matter is any substances that occupies spaces and has mass
describe photosynthesis
Mavis Reply
What is equilibrium
What is equilibrium
like corporal intern balance right?
on my own understanding is just a balanced state
photosynthesis is the process by which plants and other organisms convert light energy to chemical energy
what is a chromosome?
Wise Reply
Are thread-like structures located inside the nucleus of animal and plant cells.
what are the difference between Biotic community and Ecological nitche.
Ganiyat Reply
what is the celll
A cell is the simplest bit of living matter that exist independently
cell is the basic unit of life
what is ecdysis
what is genetics
Sebastian Reply
The cell is the simplest bit of living matter that can exist independently.
what happenes when the cell of an organism Is removed?
Isaac Reply
The cell will not function properly
what is cell
Maarig Reply
cell is stractural and functional unit of our human body.
The study of cells are referred to as?
Kenneth Reply
what is active transport
johnny Reply
is the movement of molecules through a semi permeable membrane with the use of energy
is the movement of substances across a membrane against the concentration gradient by using energy.
what is living things
Aminu Reply
these are organisms that take in respiratory gases e.g plants and animals
they are organisms that undergoe the various life processes such as growth, respiration, reproduction, excretion etc
what is gland
an organ synthesizes a substance such as hormones or breast milk
Why do plants contain oxygen
Alfonso Reply

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