Colors of autumn 94 model nude3/16/2024 ![]() ![]() ![]() The best conditions are warm, sunny days and cool nights without frost, which contrary to common belief are not necessary for the colour transition and may cause leaves to fall prematurely. When hard rains combine with wind, the trees may be stripped of their leaves before they reach their peak. Heavy rains also inhibit the best autumn colour. Drought conditions will cause leaves to fade, turn brown and fall with only a trace of colour. Some autumns are not as colourful as others. These same pigments frequently combine with the yellow carotenoid pigments to produce the bronze and deep orange hues of other hardwood trees. They also give the familiar colour to such common fruits as cranberries, plums, grapes, apples, cherries and strawberries. Anthocyanins are responsible for the resplendent reds of maples, oaks, sumac, dogwood, heaths and black gum. These red substances are not present throughout the growing season as are the yellow carotenoids, and only develop in late summer as a result of a change in the metabolic breakdown of sugar. The reds and purples of autumn foliage result from the presence of another group of pigments called anthocyanins. The North American red maple has been introduced into many countries, and selective cultivation has yielded many domestic varieties with such enticing names as October Glory, Red Sunset and Autumn Flame. Yellow autumn foliage is common in the temperate latitudes worldwide, but the vibrant reds occur only in North America, Japan, North and South Korea and northern China. Unlike other coniferous trees, the tamarack sheds its needles in autumn. The long, slender needles of the tamarack give its branches a delicate, feathery appearance. The tamarack, which belongs to the larch group of coniferous trees, turns from light green to rich, translucent gold. The heath family, which includes blueberries and other woody shrubs such as leatherleaf, bog rosemary, Labrador tea and sheep laurel, turn a vivid crimson in autumn. Two groups of plants, in addition to sphagnum moss, do thrive in bogs, however- the heath and the larches - both of which sport vibrant colours in autumn. The water in bogs is highly acidic and low in oxygen, characteristics not suited to many plants. A bog is a type of wetland in which sphagnum moss is the principal plant cover ( see Swamp, Marsh and Bog). One of the most colourful habitats in Canada is the bog. An example of how carotenoids do not need sunlight is seen in the yellow colour of grass that has been temporarily shaded from the sun by a piece of wood or a rock. Carotenoids, unlike chlorophyll, do not require sunlight for their synthesis, so they are unaffected by the shortening days of autumn and their colour dominates with the disappearance of chlorophyll. Carotenoids are common in many other living things, imparting the characteristic colour to canaries, corn and carrots, as well as buttercups, bananas and egg yolks. These colourful yellow pigments confer the Midas touch to aspens and to many other trees such as birch, cottonwood, alder, hickory, maple, sycamore and black cherry. One group of substances that shows up once the amount of chlorophyll diminishes is the carotenoids. As the amount of chlorophyll in the leaf decreases, other colourful substances that were always present but had been masked by the green become visible. Also, cool autumn temperatures slow the passage of nutrients into the leaves and this further decreases the synthesis of chlorophyll. But as autumn approaches and the hours of daylight diminish, the production of chlorophyll slows down. During summer when the days are long and sunlight is plentiful, chlorophyll is synthesized in a steady, abundant supply, so that throughout the season the leaves remain green. Sunlight is also necessary for the synthesis of chlorophyll itself. Chlorophyll is essential for photosynthesis, the process which converts the energy of sunlight into sugar. In spring and summer the most abundant substance in leaves is chlorophyll, which gives them their green colour. Within all leaves there is a blend of colourful substances temperature, rainfall and length of day determine which of these will dominate in the different seasons. The transformation from green to yellow, amber, crimson and purple is caused by a fascinating chemical process. Vibrant colours are one of the delights of autumn in Canada. ![]()
0 Comments
Leave a Reply.AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |