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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's the main function of the CELL
Victor Reply
Is the smallest unit of an living things
Chanda Reply
Okay
Jason
What is a cell
Jason Reply
A cell is the basic unit of life.
Bernard
what is the photosynthesis
Brian Reply
describe cellular event during meiosis
Ruth Reply
what is reproduction
Ruth
reproduction is the process by which living organisms give birth to new offsprings of the same kinds
Bernard
Reproduction is a process by which organisms give rise to new members of their species
Fru
Reproduction is the process whereby living organisms produces the young ones of their own kind to ensure continuity of life
Eunice
what are the example of photosynthesis
Gamshe Reply
Is how plant covert sugar and energy, air and sunlight into energy to grow
Timileyin
An example of photosynthesis is how plants convert sugar and energy from water, air and sunlight into energy to grow.
Bernard
Pls how fertilization occurs in the womb
Rebecca
Pls am asking how does fertilization occurs in the womb
Rebecca
An egg is released in the ovary of a woman during ovulation. in the presence of a sperm this egg cell fuses with the sperm cell to form a zygote ( fertilization) this zygote now moves thru the fallopian tube down to the womb where implantation takes place. the zygote develops thru to a baby
Fru
how are you everyone in here
Brian
My cordial salam to everybody. I have a question to all. What do you mean by plasma membrane?
Mahmud Reply
Plasma membrane or Cell membrane is the outer layer of tissue surrounding the whole or part of an organ. in addition, it is the outer flexible or semi-flexible covering or waterproofing whose primary function is to exclude water.(usually in plants and animals).
Job
I have a question .... Why cell wall is not present in animals cells and why it is present in plants cells?
ShAmy
what is glucose
Sisay
how alkali metal form
Puskal Reply
what is a cytosol
Siddeeqah Reply
cytosol is the internal fluid of the cell and a large part of cell were metabolism occur
Bernard
u are right dear.
Job
what is cell
Prince Reply
I think that cell is structural unit of our body. Because I have come to know that cell is the structure and biological function of an organism in the eye of scientists.
Mahmud
Cell is the fundamental, structural and functional unit of life
Winifred
Absolutely you are right. But what do you mean by life?
Mahmud
cell is the basic unit of life
Siddeeqah
life is the study of living organisms
Bernard
Cell is the basic, structural and functional unit of life. therefor no living organisms exist without a cell or a healthy cell.
Job
synthesis of 1 molecules of glucose requires
Purvesh Reply
what is the chemical composition of water
Abigail Reply
h20
Rita
h20
Asad
H20
Mathews
H2o
Bernard
H2O
Michelle
H2O
Emzzy
What is skeleton
Emzzy
skeleton is an internal or external framework of bones
Michelle
Skeleton is the structural frame work of the body
Niimat
Skeleton is the internal bony framework of the body of living organisms.
Job
Oh, how's is it going..
Brian Reply
not too good
Monique
hy
Adeola
hi
Imamkasim
hi
Veronica
Any one else taking Bio 1406 with Stephanie Martin?
Veronica
where is it ?
ShAmy
am here Veronica
iyota
Not bad
Winifred
Part of compound microscope
Bakish Reply
a. body b. stage clip c. adjacent knob d. arm e. eye piece
Kpodo
E
Rita
give five difference between worker and queen bee.
Imamkasim
How do u know when you want to urinate
Akpo Reply
how do you know when you want to urinate
Akpo
I don't know please explain
Coded
As the bladder fills up .. the signals are sent to the brain specifying that its filling up and should be emptied and the fuller it gets, the more signals/ alerts are sent to brain ...leading to the urge to urinate .... to go pee
Khalida
OK thank you
Coded
hello
Issiya
hi
Abigail
wat
Gamshe

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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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