pollen tube
The ________ grows through the stigma and style by dissolving the tissues with the help of enzymes and reaches the ovary.
Self sterility
________: This is a condition in which even if the stigma receives pollen from the anthers of the same flower, the pollen fails to undergo further growth.
pollen grains
The ________ are stick or spiny to enable them to be carried by the insects easily.
Rafflesia
Elephophily is found in ________ whose flowers are very large and are found at ground level.
Scent
________ and nectar need not be produced by flowers.
Pollen grain
________ germinates only if it falls on the stigma of the same plant species, otherwise, it disintegrates.
embryo sac
The ________ contains seven (3+3+1) cells 3 cells at the micropylar end- one egg cell and two synergids,
ovule
The ________ is destined to become the seed and the ovary to become the fruit containing the seed inside.
Fertilisation
________ is the union /fusion of the nuclei of male and female gamete.
Herkogamy
________ (Mechanical or Structural barriers): In some flowers, the pollen of a flower can not reach the stigma of the same flower.
Artificial pollination
________: When man himself transfers pollen to the stigma it is called ________.
aquatic plants
Water- pollinated (or hydrophilous) flowers are found only in ________.
Papaya
(________ usually has separate male and female trees, but less frequently there may also be a hermaphrodite tree bearing both kinds of flowers)
special features
Wind- pollinated (or anemophilous) flowers usually possess showering ________.
self pollination
Heterostyly: In such flowers, the stigma and anthers grow at different heights which do not favor ________.
small opening
The integuments leave a(n) ________ in the micropyle at one end (for the entry of the pollen tube)
Pollination
________ between flowers of the same plant is considered self- pollination on account of the common genetic characteristics- i.e.
mature pollen grain
The ________ is a cell with a double wall- the outer exine and the inner intine.
Unisexuality
________: The flowers may be either male or female and they may be borne on separate plants.
central cell
The ________ is different containing two nuclei called polar nuclei.
Pollen
________ is produced in very large quantities.
modem times
In ________, artificial pollination (also called artificial crossing) is a standard practice adopted by plant breeders and scientists in their efforts to evolve new varieties.
ovule
The ________ is the inner part of the ovary.
pollen grains
In some plants, the ________ have a specific gravity almost equal to that of water so that they remain floating below the surface of the water.
pollen grain
The ________ falling on the stigma is stimulated to germinate due to the secretion of sugars by the stigma.
pollen grains
The stigmas are feathery and hang out of the flower to trap the ________.
pollen grain
The ________ is the male gamete.
ovule
Each ________ has one or two protective coverings, the integuments.
Pollen grains
________ are light, dry, and smooth so that they can easily be carried away by the wind.
pollen grains
The ________ of one flower get attached to the feet of elephants and may be carried to the stigma of another flower when trampled by those feet.
In some rare cases, as in pansy, some flowers growing close to the ground level, do not open at all (cleistogamy, cleisto
closed), the anthers and stigma lie close to each other which mature at the same time, and self-pollination is assured
Unisexuality
The flowers may be either male or female and they may be borne on separate plants
Example
palms and papaya
Dichogamy
(Different timings of maturation of androecium and gynoecium)
Examples
bhindi, sweet peas, salvia, and sunflower
Examples
custard apple, peepal
Self-sterility
This is a condition in which even if the stigma receives pollen from the anthers of the same flower, the pollen fails to undergo further growth
Examples
ray florets of sunflowers, orchids, etc
Herkogamy (Mechanical or Structural barriers)
In some flowers, the pollen of a flower cannot reach the stigma of the same flower
Heterostyly
In such flowers, the stigma and anthers grow at different heights which do not favor self-pollination
Examples
primrose, oxalis
(Example
Maize)
Example
Vallisneria
Examples
Bignonia, canna
Artificial pollination
When man himself transfers pollen to the stigma it is called artificial pollination
The mature pollen grain is a cell with a double wall
the outer exine and the inner intine
The embryo sac contains seven (3+3+1) cells 3 cells at the micropylar end
one egg cell and two synergids,