Flowering Regulation | Genetic Control of Flowering
Control over the time of flowering is essential for the survival of flowering plants (angiosperms). Insect pollinators may be present only at certain times, unless an insect-pollinated plant is flowering at that time, pollination and the production of the next generation cannot occur. Embryo and seed development may be successful only under certain climatic conditions. The ability to respond to environmental cues is an essential factor in the regulation of flowering.
While the basic biochemical sequence of events may be common to all angiosperms, the specific regulatory steps vary greatly among species. A floral promoter is produced by the leaves and is transported to the shoot apex, which results in the initiation and, ultimately, the production of flowers. To analyze control points in this sequence, it is helpful to focus separately on environmental signals such as temperature and photoperiod and the way organs perceive and respond to these signals.
Chemical Communication
The regulation of flowering requires interactions between the shoot apex and other organs and thus depends heavily on chemical signals. There is strong evidence for the existence of a floral promoter called florigen, which may be produced in the leaves. The existence of florigen was first proposed by M. Kh. Chailakhyan, a Soviet plant physiologist, in 1937. Florigen was believed to be produced in leaves, because if leaves were removed before the photoperiod was right for flowering (a process called photoinduction), no flowering occurred. Later work by Anton Lang showed that the plant hormone gibberellincould induce flowering in certain plants, even without appropriate photo-induction. This prompted Chailakhyan to consider the possibility that florigen was actually composed of two different substances, gibberellin and a new substance he called anthesin.
In the late 1970’s Lang, Chailakhyan, and I. A. Frolova, working with tobacco plants, discovered that there was also a floral inhibitor they called antiflorigen. Later, several genes controlling the production of an inhibitor in pea cotyledons and leaves were identified in other laboratories. In addition to leaf-derived inhibitors, root-derived inhibitors have been shown to regulate flowering in black currant and tobacco plants. Aside from the clear role of gibberellin in flowering, none of the other promoters and inhibitors has been identified. Nutrient levels and allocation throughout the plant may also control the time of flowering.
Photoperiod
One major role of environmental signals is to control the timing of the production of florigen and antiflorigen.
Continue of the article: Photoperiod
Circadian Rhythms
How the perception of light by phytochrome is linked to the production of gibberellin and anthesin in long day and short day plants is not clear.
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Temperature
Plants also use temperature as an environmental clue to ensure flowering. Assessing two environmental factors provides added protection.
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Genetic Control of Flowering
The Maryland Mammoth, discussed above, is an example of a short-day plant resulting from a mutation.
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See also: Flower types




Grass perennials | Perennials shrubs and Flower Garden
March 29, 2023 by maximios • Plants
Except botanical descriptions of plants in the special literature (the agricultural technician, flowering terms, the native land, grades) in our opinion not enough attention is given to the shape of a plant, its architecture and variability during season. But without this the work of a landscape architect is complicated and frequently contains obvious errors, but they are not obvious at once. If we are talking about own garden where we can change compositions infinitely, but about an order, these errors can be always corrected. Certainly, such characteristics of plants are individual enough from the point of view of the author. We would like to share with you our many years experience in area of creation of decorative gardens and to try to give to dry encyclopedic descriptions of plants an art shade, to see a plant not only as a biological kind, but also as an architectural form with all merits and demerits. We begin these short reviews with Grass perennials as with the most changeable group (except trees and bushes).
In our collection today is more than 500 only biological kinds (except grades), BUT experience shows that it is possible to allocate a group of 50 kinds: with one prominent feature – decorative effect during all season. They are beautiful before flowering, perfectly well hold the form, «do not collapse”. They can be used both in combinations, and in strip landings. If they are planted without any obvious landscape errors do they will never lose. Their weakness is early spring when the plant intensively grows, but also at this time some of them, for example young ferns give a unique picture. Throughout all season, up to approach of the first frosts, grass perennials will look it great in your garden. Many of these plants either are undeserved forgotten or have not received sufficient distribution yet. We specially don’t talk about botanical description and agricultural technician because special literature is rich with these details.
Aruncus the Ordinary. Aruncus Vulgaris.
Very powerful plant, perfectly well holding its bush, in height up to 2 meters.
Continue of the article: Aruncus the Ordinary. Aruncus Vulgaris.
Ligularia dentata
Very dense bush with leaves of various colour (from light green with the return lilac part to is dark-purple – grades Desdemona, Othello).
Continue of the article: Ligularia dentata
Petasites amplus. (Butterbur)
Imagine the leaves of coltsfoot to 80 cm in a diameter, forming a dense bush in height up to 1,5 meters, not losing its shape during the hole season.
Continue of the article: Petasites amplus. (Butterbur)
Pursh wormwood. Artemisia purschfan.
From a series of silver plants. Well and densely grows on a shining sun, in a penumbra extends and lays down.
Continue of the article: Pursh wormwood. Artemisia purschfan.
Woolly woundwort
Continues the series of silver plants. Can be added to middle height cover ground group.
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Multicoloured spurge. Euphorbia polychrome
And here is the plant that is beautiful when blossoming, but also it is not less fine after. Gives very dense spherical bush in height up to 50 sm.
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Tumbleweed. Gypsuphila paniculate
During blossoming of an adult plant forms an openwork white cloud to 1,5 m in diameter and it continues dismiss within 1,5 months.
Continue of the article: Tumbleweed. Gypsuphila paniculate
See also: Perennial Flowers Garden, Tips for Your Garden, Creation of Flower Beds