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Bilateral flowers, with distinct up-down orientation, came about independently in a number of different plants like: violets, orchids and peas. [233] [234] United petals, petals that unite into a single bell shape came about independently in blueberries, Ericaceae and other plants. [235] Hummingbird flowers are scentless tubular flowers that ...
An image of multiple chromosomes, taken from many cells. Plant genetics is the study of genes, genetic variation, and heredity specifically in plants. [1] [2] It is generally considered a field of biology and botany, but intersects frequently with many other life sciences and is strongly linked with the study of information systems.
It is a common concept in animal evolution but, with plants, it is often overlooked because many plants are hermaphrodites. Flowering plants have many sexually selected characteristics. For example, flower symmetry, nectar production, floral structure, and inflorescences are among the secondary sex characteristics acted upon by sexual selection.
For example, the gene for flower color in pea plants exists in two forms, one for purple and the other for white. The alternative "forms" are now called alleles. For each trait, an organism inherits two alleles, one from each parent. These alleles may be the same or different.
Flowers emerged in plant evolution as an adaptation for the promotion of cross-fertilisation (outcrossing), a process that allows the masking of deleterious mutations in the genome of progeny. The genetic masking effect of cross-fertilisation sexual reproduction is known as genetic complementation . [ 23 ]
A plant morphologist makes comparisons between structures in many different plants of the same or different species. Making such comparisons between similar structures in different plants tackles the question of why the structures are similar. It is quite likely that similar underlying causes of genetics, physiology, or response to the ...
The blooming times of the flowers have also been found to coincide with hummingbirds' breeding seasons. The floral characteristics of ornithophilous plants vary greatly among each other compared to closely related insect-pollinated species. These flowers also tend to be more ornate, complex, and showy than their insect pollinated counterparts.
Cross-pollination involves the transfer of pollen grains from the flower of one plant to the stigma of the flower of another plant. The main characteristics which facilitate cross-pollination are: Herkogamy: Flowers possess some mechanical barrier on their stigmatic surface to avoid self-pollination, e.g. presence of gynostegium and pollinia in ...