Angiosperms
Angiosperms are flowering plant. Their seeds are covered by fruits. Their fertile leaves bear ovules. Flower are produce on these flower. They are also produce seed. The fertile leaves are folded and joined from ovaries. The ovary us changed into fruit after fertilization. They have more than 235,00 known species of angiosperms. Angiosperms are hetrosporous plants. These are most successful plants of earth. These plants produce flower fruits and seeds. Body of Plants The plant body angiosperms is saprophyte. It is composed of root, stem and leaves and reproductive part (flower). Root is used for anchoring and absorption of water an salts.Roots shows both positive and negative phototropism. Some plants root is used for vegetative reproduction. Stem is supportive structure. Stem geoteropism is negative and positive phototropism. Leaves arise form the branches of stem. Leaves have pedicel and lamina. Mesophyll cell is present in the lamina. Their function is absorption of light and photosynthesis. Stomata of leaves exchange gases and perform transpiration. Flower is reproductive part of the body. It has sepals, petals, stamen and carpel.
Process to reproduce
Microsporophyll (stamens) are male reproductive part of flower. Their number is variable in species. It consist of anther and filament. The anther consists of four pollen sacs.Each stamen is develop from separate primordium from floral axis.
Megasporophyll (carpel) is female part of flower. It has central position in the flower. A carpel has three part ovary, style and stigma. Basel broader part of carpel is ovary. Stigma is terminal part of carpel which receives pollen grain. Ovule Ovary contain one or more than one ovule. Ovule consistes of and outer integuments and inner nucellus tissue. Ovules are borne on specialized tissues called placenta. The position of placenta is variable in ovule. Double fertilization The fission of two male gametes with two cells simultaneously is called double fertilization. It special process. It is found in angiosperms. The pollen tube grow through style. It enters the ovule and reach female gametophyte. Male gametes release there. One male gamete is fuse with egg and form zygote nucleus. This zygote nucleus is secrete thick wall around it and become oospore. Oospore is first cell of the saprophyte generation. The second male gamete is fuses with secondary nucleus and form primary endosperm nucleus. So it called double fertilization. It is also known as triple fusion.
Seed
A ripened ovary protected by seed coats enclosing a resting embryo provided with stored food either in endosperm or cotyledons is called seed. Seed may be endospermic or albuminous when endosperm is present grain of maze. It may be non endospermic or ex albuminous in which food in endosperm is digested and stored in cotyledons (pea seed). There are different structure of seed in dicots and mono cots. Dicote has di cotyledonous seed. Dicotyledonous seed is, seed with single cotyledons e.g pea seed. In dicot seeds the embryo consists of a short axis. The embryonal leaves are attached to it. The part of the axis above the point of attachment of cotyledons is epicotyl. The part of the the axis is below the point of attachment of cotyledons is hypocotyl. At the upper end of the epicotyl a minute bud called plumule. It is present between the two cotyledons. It gives rise to embryonal shoot. The lower end of the hypocotyl is radical which give rise primary root.
Monocots have mono cotledonous seed grain maize. In monocot seeds the cotyledons is terminal.The upper part of the embryonal axis bears plumule and the lower contains radical
Fruit
The ripened ovary is called fruit. The seed are enclosed with in fruits in angiosperms. It protects and disperses seeds. The ovary wall undergoes changes to form the fruit wall (pericap). It pericap may be dry or fleshy. Seed usually undergoes a period of rest. It germinates in suitable and produces a seedling. This seedling gradually.
Seed
A ripened ovary protected by seed coats enclosing a resting embryo provided with stored food either in endosperm or cotyledons is called seed. Seed may be endospermic or albuminous when endosperm is present grain of maze. It may be non endospermic or ex albuminous in which food in endosperm is digested and stored in cotyledons (pea seed). There are different structure of seed in dicots and mono cots. Dicote has di cotyledonous seed. Dicotyledonous seed is, seed with single cotyledons e.g pea seed. In dicot seeds the embryo consists of a short axis. The embryonal leaves are attached to it. The part of the axis above the point of attachment of cotyledons is epicotyl. The part of the the axis is below the point of attachment of cotyledons is hypocotyl. At the upper end of the epicotyl a minute bud called plumule. It is present between the two cotyledons. It gives rise to embryonal shoot. The lower end of the hypocotyl is radical which give rise primary root.
Monocots have mono cotledonous seed grain maize. In monocot seeds the cotyledons is terminal.The upper part of the embryonal axis bears plumule and the lower contains radical
Fruit
The ripened ovary is called fruit. The seed are enclosed with in fruits in angiosperms. It protects and disperses seeds. The ovary wall undergoes changes to form the fruit wall (pericap). It pericap may be dry or fleshy. Seed usually undergoes a period of rest. It germinates in suitable and produces a seedling. This seedling gradually.
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