seeds and fruits Flashcards
how does pollination occur
its the transfer of pollen from the anther (male) to the stigma (female) pollen is released when the anther matures. pollen is transferred by the wind or insects
what are the two types of pollination
there’s cross-pollination and self-pollination
what is cross-pollination
plants whose flowers require pollen from another plant of the same type for fertilization
what is self-pollination
plants that are fertilized from the pollen of that same flower. they may also be pollinated by other flowers on that plant
how does fertilization occur
it occurs after pollination and is defined as the union of the male and female gametes.
after pollen lands, on the stigma, the pollen grows a tube down to the style to the ovary and enters the ovule. the male gamete is released to create a zygote
the nucleus of the male gamete fuses with the ovule in the female ovary to create the seed
how long does fertilization take
6 to 25 hours
what happens after fertilization
the zygote grows and accessory flower parts fall off (except if used to develop accessory fruits)
what happens of fertilization doest occur
the flower will die
how do fruit set and seed formation occur
only a small percentage of flowers develop into fruits many can be unpollinated or abort during development.
the degree of fruit set is thought to be linked to plant hormones environmental conditions are also important in fruit set
what is the seed
the matured ovule created by the pollen fertilizing the ovule
what are the basic components of the seed
embryo, food storage tissue, seed coat (testa)
what does the embryo consist of
cotyledon(s), plumule, radicle
what can the embryo food consist of
starch, oil, protein, or carbohydrates
what is the endosperm
the main storage structure in many monocot seeds and most grasses
in most dicots where is the food stored
in the cotyledons
what is the testa
the seed coat and is a tough covering layer that protects the young embryo from damage and it comes from the mother plant
what is a fruit
a fruit includes tissue that develops from the mother plant along with the seed. fruits may protect or help disperse the seed
what is the function of a fruit
it is a mature ovary containing seed(s)
what are accessory fruits
other floral parts that help make up the fruit such as receptacles. ex the fleshy part of the strawberry is from the receptacle
after fertilization how many seeds can a fruit have
could have one or more
what is a dry fruit
the tissue that comes from the mother plants is dry when mature. ex peas, canola, wheat
what is a fleshy fruit
the tissue that comes from the mother plant is fleshy when mature. ex peach, tomato, pear
how can we further classify dry simple fruits
dehiscent and indehiscent
what is dehiscent
the fruit splits open to release seeds
what is indehiscent
the fruit remains intact (seeds aren’t released)(seed remains trapped in fruit)
what are two examples of dehiscent, dry, simple, fruits
legumes and siilique
what are legumes
fruit formed from a single pistil that is usally compound. it has multiple ovuels within that one ovary=many seeds
ex chick peas, lentils, chick peas, beans
describe the structure of the legumes
the mature ovary wall is split into two pieces called the VALVES. there is a single row of seeds attached to a common placenta along one edge. they split apex to base when mature
what is a silique
a fruit formed from a single pistil that is a compound and has multiple ovules in the ovary=many seeds.
ex canola, mustard
what is the structure of a silique
they are similar to legumes but have two compartments in between the two valves. the two compartments are separated by the false septum. they often have a beak(a point at the end). they split base to apex
whats are two examples of indehiscent (simple, dry fruit)
achenes and caryopsis
what are achenes
they are produced from a single sample pistil. they only have only one seed per fruit. when mature it can be separated to expose the seed. ex sunflower, safflower
what is caryopsis
the ovary wall and seed cant be separated
it’s like the nut but instead of the seed being free inside. in the caryopsis the seed grows so big it grows into the ovary wall
ex. wheat, rye, barley
