วันพุธที่ 11 สิงหาคม พ.ศ. 2553

Fertilization and dispersal

Fertilization and dispersal
Main article: biological dispersal

Cassia Fistula. A hermaphrodite flower showing both male and female parts.Some flowers with both stamens and a pistil are capable of self-fertilization, which does increase the chance of producing seeds but limits genetic variation. The extreme case of self-fertilization occurs in flowers that always self-fertilize, such as many dandelions. Conversely, many species of plants have ways of preventing self-fertilization. Unisexual male and female flowers on the same plant may not appear or mature at the same time, or pollen from the same plant may be incapable of fertilizing its ovules. The latter flower types, which have chemical barriers to their own pollen, are referred to as self-sterile or self-incompatible (see also: Plant sexuality).

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