Potassium K is also important for flower and fruit growth as well as in assisting with photosynthesis in shady conditions.
Fertilizers used on flowers should contain low levels of nitrogen relative to phosphorus and potassium. A formula 5 percent nitrogen, 10 percent phosphorus, 10 percent potassium is ideal. Calcium Ca , magnesium Mg and sulfur S are also required by plants in fairly large amounts.
Don't worry about supplementing your fertilizer with these nutrients unless a soil test recommends it. Most soils provide adequate amounts for plant growth. Calcium may be in short supply in acid soils, but many plants--blueberries and azaleas among them--prefer these conditions. Micronutrients are those that are required for plant growth in very small amounts.
Two others that may be essential for some plants are silicon Si and cobalt Co. Shortages of these elements are usually related to a soil that is too acidic or too alkaline for the plant, interfering with its ability to absorb the nutrient from the soil.
The most common shortage is that of iron, resulting in a condition called "chlorosis. Their research here also speaks to the message: Life yearns for more. Scott Armbruster is a professor at the University in Portsmouth in England, who spoke with me from his own quarantine in a remote corner of the Isle of Wight. Armbruster studies the coevolution of plants and the insects that pollinate them. Such is the delicate balance of evolution: There is a flower optimized for a bee to land on it, and a bee capable of landing on that flower.
These partnerships have co-evolved for millions of years, and they exist everywhere in nature. When Charles Darwin, for example, saw an orchid with an inch-deep nectar well, he predicted that there must be an insect with a ridiculously long mouth to reach the sweet stuff.
He, of course , was right. Like Darwin, Armbruster prefers the type of science that involves adventuring out into the world and making careful observations of life doing its thing. His hypotheses, and his experiments to test them, are derived from that fieldwork. Trigger plants grow like snapdragons do here in the US: They have tall stalks, encrusted with jewel-gorgeous flowers that point outward toward the horizon.
On this day in Australia, a branch had fallen from a tree above, knocking the vertical stem of the trigger plant so that it was lying on the ground. But this is not a good position for the trigger plant to be in. A sideways flower messes up the giving side of the equation, too: If the pollen is placed on the wrong side of a bee, it may never pollinate another flower.
Even though it had been pinned down, Armbruster noticed it had started to rotate its flowers back to the proper position for pollination. Next, Armbruster wanted to know if he could recreate this artificially.
What he saw could have been a fluke So he found a new trigger plant and tied it down, and photographed its flowers every six hours. Looking through the scientific literature, Armbruster was surprised that no one had documented this small, precious phenomenon before. So over the past decade, Armbruster and his colleague Nathan Muchhala, an evolutionary ecologist at the University of Missouri, have been documenting natural instances of this phenomenon in the wild and performing experiments to see if flowers around the world also try to right themselves.
Their paper contains data on 23 species, from the trigger plants of Australia to bell flowers and heath in the cloud forests of Ecuador to buttercups in Alaska. Armbruster and Muchhala hypothesized that this adaptation would only be present in flowers that need to be kept in a very precise horizontal orientation to be pollinated.
To understand this, it helps to think a little more closely about flowers and their shapes. Many flowers are classically radially symmetrical, like a sunflower or a tulip. These even shapes allow pollinators to land on them from many angles, which means they are less likely to be devastated when their stems bend, the duo reasoned. Some flowers, however, are just bilaterally symmetrical — like we are — with one line of symmetry running down the middle.
These flowers often rely on a specific orientation for pollinators to be able to land on them. Trigger plants, snapdragons, and orchids show this type of symmetry. To clarify: This picture b is of a flower called mountain larkspur. A bee hoping to get at its nectar only has one place to land. See the arrow. Here is a toad lily a. It has radial symmetry, and a bee can pollinate it from many approaches. Armbruster is cautious about saying this is the first scientific documentation of the phenomenon.
And a caveat: This paper is not an exhaustive survey. In that batch, there were only three types of radially symmetrical flowers. The new study finds that it exists, and that it is probably the result of the careful dance of evolution: For millions of years, flowers have had to deal with random chaotic accidents nature thrusts on all living things.
Those that have adapted to accidents have survived. They are not human, with our complexities, with our troubles. I am saying they can be a comfort and sometimes, even, something of a totem of resilience.
Having moved his lab to his home, LoPresti has been passing the time making observations of how the desert poppy plant droops its leaves at night and then perks them up before sunrise. LoPresti noticed that this behavior was never recorded being observed in the desert poppy. I have to admit something now: The story about my little basil plant ends poorly. The problem is, I think I tried to plant it in soil before the roots were mature enough.
0コメント