Why can the hollow trees live – Sohu 2828创业网

Why can the hollow trees live? Why would the growth of sunflower Xiangyang – Sohu? Some flowers grow to the sun, this is why? Sunflower is the most representative of these plants, it is controlled by the growth hormone in the body, so follow the sun. The growth hormone is a plant growth hormone called indole acetic acid. This is the American plant physiologist Fritz · discovered in 1926; winter. He let the plant’s sheath to get a side of the sun, the sun can not get the results, the results of the gradual bending to the side of the sun. Thus, he isolated the plant growth factor – IAA – from the sheath. Scientists have found that this compound is afraid of the sun. So, when the sun shines, it ran to the side of the sun does not result, promote the accelerated growth of the light shading part, part of slow growth. Because of the action of gravity, the plants turn to the sunny side. Why can the hollow trees live? We often see some hollow tree is still alive, this is why? To answer this question, we must first understand the composition and structure of each part of the trunk trunk function. The trunk cross section, from inside to outside, the central part of the hard wood called xylem, the majority of the trunk; close to the outside of the xylem, several layers have the ability to divide the flat cells, called formation layer; forming a layer called the phloem, cambium and phloem is part of the two we often say that the bark inside. Due to the formation of layers of cells have the ability to divide, to produce inside the xylem, phloem outward form, so that the trunk by bold. The cells of the xylem are connected up and down to form a tube that transports water and inorganic salts from the roots to the branches and leaves. Phloem cells transport organic matter from leaves to stems and roots. As the trunk grows year by year, the wood in the middle of the trunk will die. When the scars or cracks appear on the trunk, some bacteria and fungi to drill into the heart of a tree in the tree for food, after a considerable period of time to eat empty heart. Although the heart of the tree is empty, empty is only part of the heartwood of wood, sapwood xylem is good, also has the function of transportation, can continue to be water and inorganic salt transported to the foliage. Therefore, hollow trees still can grow normally. Lotus why there are so many holes? Also called lotus, lotus, water lily genus. Rhizome internode hemitropous, hypertrophy, dilated, with most longitudinal ventilation holes for breathing, exogenous whisker adventitious root. Plants cannot do without air, because the bottom of the mud in the air is very few, so long in the water plant, to adopt various means to draw air between the Lotus Festival and the festival has many roots, pass through the lotus root air holes, these holes is the air channel. Lotus root has been degraded, and the breath is by the hole, the hole hole gradually Peng stool, rice and other aquatic plant stems have not only enlarged hole. Mimosa why shy? In nature, there is a grass called Mimosa, if you gently touch the Mimosa, its open feather note相关的主题文章: