World's Nature

HOW DO THE FLOWERS BLOOM?

It is very interesting for the people how do the flowers bloom? This is one of the most often asked questions. Unfortunately, it is also one of the most difficult to answer. Each year, the unique combination of sun, wind, water. temperature, elevation precise location sets the stage for the springtime blooms. Use the following information to make your own predictions for this spring's showing.

Rain is needed in small doses throughout the winter. Too little rain provides a poor climate for seed germination. Too much rain, and the seeds could rot or be washed away. Showers too early or too late in the season may not help the flowers bloom.

Temperature is also critical. Warm days are a good indicator of a full bloom ahead. If the sun gets too hot though, (over 85 degrees F. in February/March) the seeds may become parched and seedlings scorched. Cool nights can assist flower seedlings by slowing the growth of competitors like grasses and mustards. However, very cold temperatures mean bad news for blossoms.

When will the flowers bloom? None of us knows for sure. Each year's bloom is unique in its variety, profusion and timing. From late February through March, you can find blossoms on the desert floors. To plan your visit to coincide with the peak of the bloom, take advantage of th various wildflower hotlines and information sources available through the state and national parks.

Flowers bloom to attract insects, which then carry pollen from one flower to another and fertilize the growing fruits and seeds. In other words, it's plant reproductive process.

Ove Nilsson is Professor of Plant Reproduction Biology at the Ume Plant Science Centre. His field of research is plant biotechnology - and he has a special interest in trees, particularly the poplar. But his discoveries can be applied to all plants.

"In the early 20th century, biologists had gained certain insights into why some plants flower in the spring and others in the autumn. But that was about it."

Professor Nilsson tells the exciting story of the race to discover the mechanisms behind flowering. Apparently, two camps were formed. One was convinced that flowering was governed by temperature - that plants sensed the warmth in the spring and the cooling-off in the autumn. The other camp claimed that it had to do with how long the day was. But this theory meant that plants had to be able to sense the quantity of light in some way, that the days were getting longer or shorter. This in turn required some kind of built-in gauge of time, a clock.

Around a hundred years ago, people realised that plants are able to gauge the length of the day via their green leaves, causing the shoots to form flower buds. In other words, some kind of signal must go from the leaves to the tips of the shoots, though the exact nature of this signal was a mystery.

Grafting leaves from plants that had been light-stimulated to flower onto plants that had not started to flower caused the whole recipient plant to flower. This implied that some substance must have spread from the grafted leaves to the rest of the plant and initiated flowering there too.

In the 1930s the Russian biologist Chailakyan called this mystical substance florigen and thought it must be a universal substance because he could many plant species reacted to this kind of grafting. The substance spread flowering, but nobody could understand what it was. Some type of sugar molecule? A hormone?

Biochemists tried in vain to extract the substance. They found nothing and were forced to conclude that either a number of different substances are involved or that they had so far been looking for the wrong type of substance.

In May 2005, Ove Nilsson showed that the second explanation was the right one - he had found the flower-initiating substance that Chailakyan predicted 70 years ago.

"We discovered that the genes that determine when flowering occurs are active in the leaves, not in the tips of the shoots where the actual flower opens. The gene that we found produces signal molecules that are conveyed from the leaves to the tips of the shoots, where they control the formation of proteins that in turn are responsible for the actual flowering."

This signal molecule is neither a sugar molecule nor a protein, but a type of messenger RNA (mRNA), a tiny piece of the genetic material that controls the formation of proteins. The point in time at which flowering occurs is thus pre-programmed in plants' genetic code in the same way as when humans and other animals reach sexual maturity.

Another viewpoint of blossoming flowers:

Flower petals breaking through the snow, an early hint of spring's arrival, hides a very complex genetic process behind its floral façade.

Flowers know when to bloom because of a gene named Apetala1. A lone master gene, Apetala1 triggers the reproductive development of a plant, telling it when it's time to start blossoming. Yes, a single gene is all it takes to make a plant start producing flowers.

A plant blooming with flowers has an active Apetala1, while a plant carrying inactive Apetala1 genes has very few flowers, if any, with leafy shoots growing in place of blossoms.

Apetala1 generates the proteins that in turn switch on more than 1,000 genes involved in the flowering process, researchers at the Plant Developmental Genetics laboratory at Trinity College Dublin (TCD) have recently discovered.

While Apetala1 was pinpointed as the master control gene responsible for flowering decades ago, this is the first time that scientists have been able to describe how Apetala1 regulates and communicates with the other "growing" genes.

“Our findings provide new, detailed insights into the genetic processes underlying the onset of flower development," said Dr. Frank Wellmer of the Smurfit Institute of Genetics, one of the study's lead authors.

When the Apetala1 gene turns on, it first commands other genes to send a "stop" signal to the plant's meristems, effectively halting leaf production. Located in the areas of a plant where growth takes place, meristems are then alerted to instead begin making flowers.

Plants blossom at different times because several factors, including the weather, temperature and the amount of sunlight the plant receives, all of which influence its reproductive development. Information about these conditions is relayed to Apetala1, which activates when it senses that the timing is right to commence flowering.

Global climate changes are having a dramatic impact on flowering times, with Britain currently experiencing the earliest flowering date in the last 250 years, according to data collected by Nature’s Calendar, a national survey coordinated by the Woodland Trust in partnership with the Centre for Ecology & Hydrology (CEH).

Using an index of UK citizen-submitted data, CEH researchers were able to compare the blooming dates of more than 405 flowering plant species and analyze how changes in climate influence a plant's life cycle, a study known as phenology. Scientists noted that spring-flowering species are more affected by temperature changes than species that blossom later in the year.

Understanding Apetala1's role in plant growth is one step closer toward genetically engineering crops to produce flowers or fruit as desired by plant breeders and farmers. The ability to control plant reproduction can also be used to reduce the time it takes for crops to mature.

"A detailed knowledge of flower formation will allow breeders to specifically manipulate the underlying developmental program and then to select for plants that give higher yields or that allow a more efficient cultivation," Wellmer told Life's Little Mysteries.

SEE HOW DO THE FLOWERS BLOOM

ALL AT ONCE ONE NIGHT A YEAR:

The mysterious night-blooming cereus just dazzled a garden in Tucson. Scientists still aren’t sure exactly how they bloom at the same time.On Friday, June 12, the world’s largest private collection of night-blooming cereus plants burst open. The flowers are a bit of a scientific mystery: They usually bloom on just one night a year, and en masse. Staff at the Tohono Chul garden, a non-profit botanical garden and nature preserve in Tucson, Arizona, often can’t tell when their record-setting collection of Cereus greggii flowers will unfurl their long, fragrant petals until a few hours before they do. And so, last Friday, the garden sent out an email with the subject line: “Bloom Night is Tonight!”

The night-blooming cereus is known for its ethereal, star-like blossoms, as well its tendency to bloom all at once. Plant-lovers often gather to celebrate its unfurling, and such gatherings are not a new idea. As the Washington Post writes, “Informal gatherings to witness the annual affair were commonplace in small-town America before World War II.” Local newspapers announced when the cereus buds were swelling and the bloom imminent, and “neighbors and strangers alike arrived for the show.”

Tohono Chul says that about 1,500 people came to the garden on Friday night, where they got to see the Cereus greggii go from a small bud to a palm-sized flower right before their eyes. In general, the blooming process happens so quickly that, as a 1934.

piece in the New York Times puts it, “Those who watch the unfolding of the petals often hope to detect an evidence of motion, but the development is so smoothly uniform that the little bud suddenly appears more widely open than the second before, without a perceptible movement.” After giving off their famously hypnotic scent, the flowers wilt just a few hours later.

The flowers, sometimes called Arizona’s Queen of the Night, tend to pop open between late May and late July. Cereus greggii (or Peniocereus greggii) are found in the dry soils of the Southwest, including southern New Mexico, southeastern Arizona and western Texas, as well as in parts of Mexico, including eastern Chihuahua, northeastern Durango, northern Zacatecas and Coahuila. Other flowers that also go by the common name night-blooming cereus grow in tropical Central and South American jungles.

“Researchers still don’t know how the flowers know when to bloom en masse,” the Tohono Chul website explains, but they believe it may be some type of chemical communication. As the garden's website writes, the flowers might bloom together on the same evening to help ensure pollination. Hawkmoths usually spread the seed of the night-blooming cereus—and, logically, “The more blooms that are open, the greater the chances of pollination.”

Ring points out that the one-night-a-year idea can get confusing. “A bloom itself will only last one evening,” she says, “but a plant may produce multiple flowers that bloom over a few nights.” Most of the flowers bloom on the same evening, in concert, but sometimes, Ring says, small groups of them bloom earlier or later than the majority.

Still, even the early or late cereus blossoms are never on their own. “We have yet to see a bloom blossom alone,” Ring explains. “[I]f we see one we can always find another one blooming, even if it is across the entire garden.”

If a flower were to somehow open without any blooming companions, Ring says, it would be all alone, and therefore lose its chance at reproduction. Giving us a human comparison, she adds: “It’s like going to a disco on a Tuesday versus a Saturday.

Why are not flowers blooming in the garden?

All of a sudden, my flower garden, which is normally full of color all year, has turned green. Why aren’t my plants blooming?

It’s so frustrating to take good care of your plants and be rewarded with a lack of blooms! In order to diagnose exactly why a plant isn’t blooming, you really have to understand the individual plant itself. Many plants have particular needs that can affect their flowering. However, if your entire flower garden has stopped blooming, there might be something else going on.

Here are the main reasons why plants don’t bloom, and some things you can do about it.

Annual plants:

Annual plants typically bloom for most of the growing season. If they stop blooming, it may be caused by:

Overfeeding:

Nitrogen promotes leaf and stem growth, so too much nitrogen results in green plants with no blooms. Even a balanced fertilizer with equal amounts of nitrogen, phosphorus, and potassium might have too much nitrogen for your flowering plants.

What to do: Water your plants really well to wash away some of the nitrogen. Stop using your current fertilizer and give your plants a few weeks’ rest before switching to one with little or no nitrogen and extra phosphorus. Fertilizers labeled as “bloom-boosting” usually have better proportions for flowering plants.

Heat:

Some plants stop flowering when stressed by the heat, particularly if overnight temperatures rise too high.

What to do: There’s not much you can do for heat-stressed plants other than keeping them alive and healthy until the weather changes.

Cold:

While cooler temperatures are often vital for the setting of flower buds, a dip too low can freeze the buds and cause a season without blooms.

What to do: Choose plants that are hardy in your climate, and protect tender plants from cold temperatures.

Light:

The amount of sunlight is crucial to getting plants to bloom. Sun-loving plants won’t bloom in shade, and shade-loving plants have trouble in too much sun. Also, some plants are “photoperiodic,” which means they bloom in response to the change in the length of daylight as the seasons progress.

What to do: While you can’t change the seasons, you can make sure your garden is getting the amount of sunlight required by your particular plants. Check to see if trees or other plants have grown tall enough to shade your garden, and move plants to a different location if there’s not enough (or too much) sunlight.

Water:

While all plants need water, some—particularly desert plants and highly drought-tolerant plants—slow or stop blooming when overwatered. On the other hand, water-loving plants can stop blooming during drought.

What to do: Check each plant’s individual water needs to make sure you’re not over or under watering.

Underfeeding:

Container plants especially are vulnerable to nutrient depletion.

What to do: Amend your soil with compost and organic matter, and feed with a fertilizer lower in nitrogen and higher in phosphorus.

Perennials, Shrubs, and Trees:

In addition to the above factors, perennials, bulbs, shrubs, and trees might be affected by:

Season:

Most plants bloom during a particular season that can last days, weeks, or even months. For example, if your garden is full of spring-flowering plants, it will only be colorful in the spring.

What to do: Plant a variety of plants in your yard for year-round color.

Plant Age:

Some plants don’t bloom until they’re mature enough, and many won’t bloom the first season after they’re moved or transplanted.

What to do: Allow time for plants to mature when young or after transplanting.

Pruning:

Plants that bloom once per year can be affected by pruning that removes tiny flower buds. For example, camellias set buds for spring blooms several months earlier, so a late fall pruning can cut off next spring’s flowers.

What to do: Make sure to prune plants at the correct time for each type.

Alternate Flowering:

Some flowering trees will spontaneously bloom very profusely one year, then take a year or two off.

What to do: This can happen naturally in some varieties, but in the future you can choose plants less prone to alternate flowering.

Complacency:

Plants bloom in order to reproduce and survive, and older settled plants may be “too comfortable” to need to bloom. Sometimes you can encourage a shrub or tree to bloom by stressing it a little.

What to do: Try root pruning to encourage your plant to bloom