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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 abiotic?
Williams Reply
state 2 abiotic factors that affect the rate of transpiration in plants?
Benenge
non living things
Chris
what is a cell
Esther Reply
what is contained in a smooth endoplasmic reticulum?
Bleyd Reply
sperm
Chris
cool
Jo
sorry i meant the structure within the smooth endoplasmic reticulum
Bleyd
what is cell made of
Jo Reply
what is sponge
Joseph Reply
what is a photometer
Abigail Reply
what is respiration
Alao Reply
Is the release of energy from food substance in a living organism
innocent
What is cytoplasm
Nitta Reply
Parasitic adaptation of tapeworm
Angela Reply
Describe osmoregulator or osmoconformers and how these tools allow animals to adapt to different environment.
Alick Reply
describe the secondary function of a leaf to a plant.
Twizera Reply
hi I'm asking a question about HIV infection, can HIV infection transmitted from Mother to unbron child? please help me I So confused.
Khushboy Reply
no it can't
Ahmad
yes it can but their is an injection that can be used to prevent it.
Gift
Ahmad how no?
Khushboy
Hi im new
innocent
no, unless when giving birth
Bright
YES
Kaole
it is can be transmitted but there is an injection that the mother is injected to prevent the disease
Nia
OK
Kaole
I agree with nia
peter
but I think HIV infection can be transmitted through blood so the unborn baby can be affected by HIV when a slight mistake occurred that what i think
Salim
yes, but there is a treatment however, using a retroviral therapy and injection to prevent the unborn child unscathed from the infection
Gula
what is the difference between primary and secondary active transport in detail? I didn't understand the steps in the textbook specifically
Fathima Reply
you are a doctor?
Mohammed
what is the meaning of connective tissue?
Mohammed Reply
what are the characteristics of living things
Owolo Reply
hi
Mohammed
what's the meaning of connective tissue?
Mohammed
Reproduction, adaptation, interaction, movement, growth, respiration, made of cells, responsive to environment (homeostasis), metabolic action (consumption of food converted into energy)
garret
Movement, reproduction, nutrition, irritability, growth, excretion, respiration, death, adaptation, competition
peter

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Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
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