How many fruits have no seed

4 anatomy of the fruit (Blaich)


4.0 seeds and fruit

Technological problems in fruit processing are often related to the construction of fruit and seeds

In popular parlance, not only is the term fruit unclearly defined, but a correct distinction is not always made between seeds and fruit.

The seed is that which arises from the ovule; the seed coat are the mature integuments.

The fruit arises from the ovary; When the seeds ripen, the seeds can remain in the fruit (closing fruits) or be released (scattered fruits)

Here's a little quiz: seeds or fruit?

What is a

  • Poppy seed

  • Peppercorn

  • Wheat grain

  • Caraway seed

  • walnut

  • hazelnut

  • Apple Core

  • Core in the strawberry jam

  • Core in the gooseberry jam

  • Sesame seed

  • Sweet chestnut

  • Sunflower seed

  • Dry bean



4.1 Fruit development

Ovary: how does it become a fruit?

  • The exocarp becomes the skin of the fruit
  • Mesocarp becomes pulp
  • Endocarp turns into skins, meat, juice
    • Integuments: submissive, hard seed coat (also slimy)

What type of fruit is present (Fig)?


Fruit formation: Another possibility (Fig)!

  • Exocarp becomes parchment skin
  • The mesocarp becomes a fibrous layer
  • Endocarp becomes stone armor
    • Integuments: brown seed coat


More complex fruits

In addition to the ovary, other parts of the flower also participate in the fruit structure

  • e.g. flower base or axis
    • with strawberries, apples, rose hips
  • Petals, stems
  • Sepals
    • with dandelions, sunflowers, Jewish cherries
  • Fruit stalks

Collective crops From many individual choricarpic carpels in a flower (Fig)
e.g. strawberry, apple, rose hip (Fig)

Infructescence: Growing together of many individual flowers of an inflorescence
e.g. pineapple, fig, mulberry

Ovary level plays a role (above, medium, below, Fig.)


4.2 Fruit types - an artificial system

Classification of fruits according to

  • Dried fruits - juice fruits
  • Closing fruits - opening (litter) fruits
  • Decay fruits - follicles - legumes
  • Nuts - capsule fruits - drupes - berries

Depending on what is placed as the top category, there is a slightly different system

EHRENDORFER (textbook Strasburger) takes as the top category e.g. the ovary type (multi-leaf, single-leaf type - chorikarp, coenocarp)


4.2.1 Opposing types

Dried fruits - juice fruits

  • When the layers of the ovary wall become tough like parchment after ripening, a Dried fruit
    • Tough wall: Sleeve, capsule
    • Woody wall: nut
  • When the outer layer (exocarp) becomes a skin and the middle (mesocarp) becomes pulp, one is created Juice fruit
    • if the inner ovary layer (the endocarp) becomes juicy, it is a berry
    • if the inner layer becomes a stony peel, we have a stone fruit

Closing fruits - opening fruits

  • Both Closing fruits the seed remains in the pericarp or at least in its inner layer (stone fruits) until the pericarp is decomposed, forcibly opened by animals (berries) or broken up by germination (nuts, split fruits)
  • Both Opening fruits the seeds are released through the natural development of the pericarp.


4.2.2 Juice fruits Berries

Berries are mostly multi-seeded, but also appear as single-leaf berries (dates).
Incidentally, the date core is a seed that has stored cellulose as a reserve, not a stone core!

Typical berries are wine, currant, gooseberries (Vitis, Ribes, Grossularia) but also deadly nightshades (Atropa) and lily of the valley (Convallaria)

Examples of special cases

  • Cucurbitacean armored berries (cucumber and pumpkin)
  • Pulp formation of the citrus fruits
    • juicy cones of the pericarp fill the ovary compartments Stone fruits

are predominantly solitary, but often occur as a collective crop

Mono-leaf drupes are most stone fruit plants (cherry, plum, peach), while elderberries and olives "stone berries" arise from several carpels (coenocarp), even if only one (or no) ovule ripens in the olives

Collect drupesarise e.g. in the blackberries and raspberries where the numerous ovaries of a flower transform into small stone fruits, which sit more or less slightly overgrown on the arched flower base

Apple fruits special cases are to be mentioned, here the axle fabric surrounds leathery or woody (bellow or nut) fruits


4.2.3 Dried fruits

as opposed to juicy closing fruits such as berries, stone fruits, which have already been discussed. Lock fruit nut

Simplest dry lock fruit.

It usually contains only one seed and falls off as a whole when ripe. The lignified pericarp is burst together with the seed coat during germination.

  • Single leaf nuts (e.g. Ranunculus)
  • Multi-leaf nuts (e.g. composites and grasses - Asteraceae and Poaceae)
  • Collective nuts (from a single flower)
    • In the case of the strawberry, numerous single-leaf nut fruits sit on the strongly arched flower base
    • in the case of the rose, on the other hand, they are sunk into the jar-shaped flower base (rose hip, Fig)

There are many special cases with nuts

  • Achene, the nut of the daisy family
    • The achenes are below, so here the fruit is still surrounded by the calyx, which can be extended upwards to form an organ of expansion (dandelion), it arises from a two-leaved ovary with a single, anatropic ovule
  • Caryopsis, the nut of the grass
    • The caryopsis is on top, but here bracts (husks) are often still fused with the fruit (oats, avena), it arises from a three-leaved ovary with an ovule
  • Both the seed and pericarp are closely connected. Dry opening fruits

  • Bellows: if the carpel pops open again at the "seam" of a dry mono-leaf fruit
    • e.g. with peony, Paeonia and delphinium, Delphinium
    • in the Apple fruit some bellows are embedded in the axle tissue
  • Sleeve: here the ripe carpel pops open both at the point of attachment and along the main nerve. (Fig)
    • While the magnolia still forms several pods per flower, we only find one in the legumes
  • Capsules: Dry multi-leaf opening fruits; they are widespread in the plant kingdom
    • (e.g. the poppy seed capsule made up of up to 20 carpels)
    • Pods are special cases of capsules, made of only two fused carpels at the edges, which separate from each other when ripe and leave a frame that carries the seeds (Fig).
    • The opening mechanisms of capsules are extremely diverse: septicidal (cracking open on the partitions), dorsicidal (on the back), completely or partially, with a window, with a lid, etc. Fissure and broken crops

Some capsules do not open at all, but rather disintegrate (decay fruits)

  • by "septicidal" splitting of single-leaf fruits, whereby the fragments can still be held together by a fruit holder (carpophor) and enclose the seeds like a nut (maple, umbelliferae, Fig)
  • through transverse fracture, e.g. the pods of the Brassicaceae (e.g. the radish, Raphanus)
  • in the dead nettle (Lamium) or with borage (Borago) the double ovary breaks into 4 partial fruits (called Klausen), this happens along real and false partitions


4.2.4 Fruit clusters

So far, we have only spoken of fruits from individual flowers - but sometimes a whole inflorescence is formed into an infructescence. Often indistinguishable from real fruits on the surface

Figs are agriculturally important here (Ficus), Pineapple and mulberry (More)

in these cases, other flower components (calyx, petals, flower axis, stems) are always involved in the structure

Understanding question: how does a rose hip differ from a fig?