Flowers, Flowers and Flowers

The most important purpose of flowering is to carry out the reproductive procedure. The period of flowering may be pragmatic outwardly from the opening of the first flowers to the death of the last ones. Annual plants flower in the first year, and biennial plants in the second. The plants Perennial herbaceous and Arboreal are flower only after having reached a certain age. For instance, many trees flower after 20 or 30 years, and several herbs flower after two to five years. Polycarpous plants are flower many times during their lifetime; Monocarpous plants like agaves, certain palms, annuals and biennials are flower only once. Many arboreal plants are distinguished by periodicity of flowering. Such as, many fruit trees flower plentifully several times every other year. Oak profusely flowers only once every five to seven years. Some tropical plants, such as, coconut palm and Caesalpinia are flower constantly.

In some species the flowers do not close until they droop. In some others the flowers may open and close again and again; for instance, saffron flowers open and close 10 to 12 times. The flowering development may last anywhere from 20 or 25 minutes (royal water lily) to 70 or 80 days (some orchids). Once the pollination occurs, the flowers quickly wither. The flowers of different plant species open at a specific time in the morning, day, or night.

The transition to flowering is one of the major phase changes that a plant makes during its life cycle. The transition must take place at a time that is favorable for fertilization and the formation of seeds, hence ensuring maximal reproductive success. To meet these needs a plant is able to interpret important endogenous and environmental cues such as changes in levels of plant hormones and seasonable temperature and photoperiod changes. Many perennial and most biennial plants require vernalization to flower. The molecular interpretation of these signals is through the transmission of a complex signal known as florigen, which involves a variety of genes, including CONSTANS, FLOWERING LOCUS C and FLOWERING LOCUS T. Florigen is produced in the leaves in reproductively favorable conditions and acts in buds and growing tips to induce a number of different physiological and morphological changes. The first step is the transformation of the vegetative stem primordia into floral primordia. This occurs as biochemical changes take place to change cellular differentiation of leaf, bud and stem tissues into tissue that will grow into the reproductive organs. Growth of the central part of the stem tip stops or flattens out and the sides develop protuberances in a whorled or spiral fashion around the outside of the stem end. These protuberances develop into the sepals, petals, stamens, and carpels. Once this process begins, in most plants, it cannot be reversed and the stems develop flowers, even if the initial start of the flower formation event was dependent of some environmental cue. Once the process begins, even if that cue is removed the stem will continue to develop a flower.

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A branch of Horticulture concerned with the rising of flowering plants (ornamental) to get flowers for cutting, for transplanting in gardens, parks and for interior decoration. A difference, based on the purpose and characteristics of the plants, is made between flowering plants raised in the open garden and those grow in greenhouses. Perennials and annuals that are modified to local conditions are planted in the open garden (phlox, peony, iris, pansy, sage, lobelia, and petunia). Greenhouse conditions are necessary for roses, carnation, and cyclamen (Thermophiles) and also for palms, cacti, aloe, and ornamental asparagus (House plants). Winter forcing is treated for lilacs and tulips.

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