The "Most Beautiful 600 Meters" in Nanjing, This Year's Leaves More Beautiful

Every autumn, there are a large number of citizens and tourists rushing to Shi Xiang Road, Nanjing, to see the "Most Beautiful 600 Meters". Because of the adequate rainfall, this year's autumn leaves will be brighter and more beautiful than previous years. "In my memory, only leaves in 2012 are comparable to this year" Dong Lina, Zhongshan Cemetery Authority Senior Engineer said. This weekend everybody can seize the time to enjoy the autumn in the road of Shixiang, and now the road is full of red, yellow and orange, staggered and intoxicated.

Autumn comes with the color change of leaves, especially deciduous shrubs. Many species of trees were planted in Shixiang Road, such as ragweed, beech, ginkgo, triangular maple, sweetgum, Pistacia wood. Trees and shrubs have been carefully designed and combined to gradually become colorful. People enjoy the beauty of autumn and are attracted by the colors.

So, why do leaves change colors in autumn? Gardening experts expressed that the leaf color changes before the frost, it is part of natural decay process. If the sunlight is sufficient, with warm day and cool night the leaf color will change even more obviously. If the autumn is always cloudy and the temperature difference is not significant, leaf color will not change too dramatically. However, climatic conditions are not the only influential factors. Another major factor is the plant’s genetics.

Most plants have synchronized leaf color changes, and some are sensitive to temperature, such as the red maple, which turns red, while other plants are slightly behind. The leaves of green plants contain a variety of pigments, such as chlorophyll, lutein, carotene, carotenoids and anthocyanins. With the drop of autumn temperatures, chlorophyll will begin to decompose and the green color subsided. Then the leaves appear red, orange or yellow. After chlorophyll decomposition, large quantities of lutein and carotene remained, once the tannin increases, the leaves will appear pale yellow to bright yellow. Examples of trees with such leaves: poplar, birch, ginkgo, Liriodendron and so on. The red leaves is caused by anthocyanins. Some of the starch stored in the leaves is converted to glucose and are delivered to various parts of the plant.

When the weather gets cold, the ability of the leaves to deliver nutrients is weakened thus the moisture in the leaves is reduced. As a result, glucose accumulates in the leaves and becomes anthocyanins. On the other hand, as decomposition of chlorophyll continues to decline, and anthocyanin gradually increased, the leaves changed from dark red to and bright red then purple. Tannins also accumulate in the leaves of species such as oaks and maples. This is why some of the leaves sometimes appear yellow and orange.