Pollen
Erica's Original Notes: Known as the 'gift of life', each pollen grain, wrapped in a waterproof coat to prevent it from drying out, contains a complete set of characteristics as it sets off on its perilous journey to unite with and fertilize the ovule in the ovary.
The pollen of each species of plants is different, very like jewellery in its intricate design. It has two covers like a football whose outer cover is made of hard leather, while the inner football cover is a rubber case, or bladder. The inner wall of pollen is made of cellulose, while the outer wall, or exine, of the pollen is made of protein and sugar, impregnated with waterproof wax and is stippled or ridged. Inside are cells with protoplasm and nuclei containing chromosomes, carrying all the characteristics of the parent plant, whether a fragile herb or giant redwood.
Rain: Plants try to protect their pollen from rain; Queen Anne Lace tips her umbels to keep her unshed pollen dry; geraniums and buttercups do also. Dandelions and crocuses close. Jack-in-the-Pulpit keeps its anthers well housed in an enclosing spathe. Iris stamens are roofed over by a broad stigma. Pea, clover and snapdragon petals protect their stamens. Bell-shaped flowers provide pretty umbrellas for theirs.
Insects: In the summer months there are thousands of these visitors to flowers; during the rain they have to stay sheltered, only to re-emerge hungrier than ever!
Paleobotany: Paleobotanists explore our past through examining the soil for pollen grains. One-foot soil depth is equal to 1,000 years; from paleobotanists we know that at one time spruce and fir were in Florida and magnolia and figs were in Greenland.
Carboniferous Age: 350 million years ago; ferns, horsetail, club mosses and early pines.
Permian Age: 200 million years ago; cycads, ginkgo, modern pines.
Mesozoic Age; 180 million years ago; primitive angiosperms, magnolia and buttercup, sequoia across the world, cypress.
Pine pollen: This has two bladder-like water wings to keep it airborne. Also firs and spruces.
Inhibitors: Some stigmas inhibit the plant's own pollen so as to prevent self-pollination, such as Californian buckeye, Zigadenus and Kalmia.
Aquatic plants: Plants growing in water have waterproof pollen, released in a bubble of air to float around to find a female. Not all aquatic plants use this method; many hold their flowers above the water and may be wind- or insect- pollinated.
Interesting Links:
Pollen: An Introduction - National Geographic 2009
.
The pollen of each species of plants is different, very like jewellery in its intricate design. It has two covers like a football whose outer cover is made of hard leather, while the inner football cover is a rubber case, or bladder. The inner wall of pollen is made of cellulose, while the outer wall, or exine, of the pollen is made of protein and sugar, impregnated with waterproof wax and is stippled or ridged. Inside are cells with protoplasm and nuclei containing chromosomes, carrying all the characteristics of the parent plant, whether a fragile herb or giant redwood.
Rain: Plants try to protect their pollen from rain; Queen Anne Lace tips her umbels to keep her unshed pollen dry; geraniums and buttercups do also. Dandelions and crocuses close. Jack-in-the-Pulpit keeps its anthers well housed in an enclosing spathe. Iris stamens are roofed over by a broad stigma. Pea, clover and snapdragon petals protect their stamens. Bell-shaped flowers provide pretty umbrellas for theirs.
Insects: In the summer months there are thousands of these visitors to flowers; during the rain they have to stay sheltered, only to re-emerge hungrier than ever!
Paleobotany: Paleobotanists explore our past through examining the soil for pollen grains. One-foot soil depth is equal to 1,000 years; from paleobotanists we know that at one time spruce and fir were in Florida and magnolia and figs were in Greenland.
Carboniferous Age: 350 million years ago; ferns, horsetail, club mosses and early pines.
Permian Age: 200 million years ago; cycads, ginkgo, modern pines.
Mesozoic Age; 180 million years ago; primitive angiosperms, magnolia and buttercup, sequoia across the world, cypress.
Pine pollen: This has two bladder-like water wings to keep it airborne. Also firs and spruces.
Inhibitors: Some stigmas inhibit the plant's own pollen so as to prevent self-pollination, such as Californian buckeye, Zigadenus and Kalmia.
Aquatic plants: Plants growing in water have waterproof pollen, released in a bubble of air to float around to find a female. Not all aquatic plants use this method; many hold their flowers above the water and may be wind- or insect- pollinated.
Interesting Links:
Pollen: An Introduction - National Geographic 2009
.
