Each part of the plant performs its main functions based on the features of its structure. But the modification of the leaves, as well as other necessary organs, allows them to acquire additional ones. Most often, they depend on the climate and growing conditions.
Modification of the leaves of the tropics
Plants of moist equatorial forests are very easy to recognize - by the characteristic shape and size of their leaf blades. In the tropical climatic zone, their woody forms dominate, giving life only shade-tolerant shrubs and herbs. The leaf blades of such plants are unusually large and wide. How to explain this structure? The thing is that one of the functions of this part is the implementation of transpiration. This is the process of evaporation of water from the surface of a sheet. The larger the plate area, the more intense gas exchange with the environment. And in conditions of high humidity, this is simply necessary to prevent decay processes.
Spines
Spines are also modifications of plant leaves. They are characteristic of those that grow in arid and desert conditions. Everyone saw the cactus spines. This is its leaves. In conditions of lack of moisture, when the transpiration process should be minimized, this is an ideal device. With such a small surface of the leaf blade and water, very little will evaporate.
However, spines of cactus and acacia are a different modification of the leaves. What's the Difference? In white acacia, hawthorn, thorns, barberries and other similar plants, thorns are modified stipules, and not the plates themselves. Their main function is to protect fragrant flowers and sweet fruits from being eaten by various animals.
Needles
A variation of the leaves is also the needles of all representatives of the gymnosperms department. Everyone remembers the children's riddle about the Christmas tree - "in the winter and summer in one color." And evergreens, all conifers are largely due to the characteristic modifications of the leaves. On a cross-section, they have a rounded or ribbed shape. Such leaves have a small area, like spines of cacti. Their stomata, through which gas exchange occurs, are immersed in the integumentary and main part of the leaf. This reduces the level of water evaporation. In the winter season, these formations are completely sealed with wax, which reduces transpiration to almost zero. Therefore, at a time when all angiosperms dump foliage for the winter, conifers and shrubs boast lush green decoration.
Desert plant leaves
It is not easy for plants to survive in arid conditions. What are the reasons for leaf modifications in these plants? They need to have such structural features that will survive during sudden changes in temperature and lack of moisture. Therefore, their leaves are often covered with a thick layer of hair, or a waxy coating. They protect plants from excessive moisture loss. There is another device. Many species of arid ecosystems accumulate water in thickened, fleshy leaves. An example of such a modification is aloe, which is often bred as a houseplant with healing properties.
Antennae
To consider the features of the following organs, let's recall what modifications of the leaf are found in the legume family. The shoots of most of them are long and thin, and the fruits, when ripe, acquire a mass that does not allow them to be held upright. But it is the most beneficial for the productive implementation of photosynthesis. What leaf modifications are found in peas? Of course, this is a mustache. So individual plates from a complex sheet are modified . With their help, the plant clings to the support, and as a result, a weak and thin stem is located in the required position.
Flakes
To understand why kidney scales are a modification of the leaf, you need to understand the structure of the bulb. Consider it with the usual leek. Its bulb, despite being located underground, is a modification of the aerial part of the plant - the shoot. This is easy to prove. The shoot consists of a stem, leaves and buds. The bulbs also have the same parts. Its flat stem is called the bottom. A bunch of adventitious roots leaves down from it. Above are several types of leaves. Young ones are green and grow from buds located on the bottom. Succulent and fleshy leaves take on this form in order to store moisture. With its help, plants in which the bulb is formed undergo drought, low temperatures and other adverse effects underground. And dry scales, which are also a modification of the leaves, protect the inner contents of the bulb from mechanical damage.
Ravenous leaves
Modification of leaves is also very dangerous for other living things. There is a whole group of carnivorous plants. They are also capable of carrying out the process of photosynthesis, i.e., they are autotrophs. But if there are no conditions for its course, then they pass to a heterotrophic method of nutrition. Using modified leaves, they capture insects and digest them. For example, in a tropical sarracenia plant, the leaves are a funnel bordering aromatic nectaries. They attract insects. Approaching, the victim begins to glide along the edges of the funnel and is trapped. In addition, the leaves also secrete special narcotic substances that immobilize an insect of any size. On top of the funnel, the sheet is twisted in the form of a hood. This fold does not allow rain to get in, mixing with digestive enzymes.
To the modifications of the leaves are the mobile tentacles of the sundew, at the ends of which there is a sticky liquid. It attracts insects that land to feast on and are trapped.
Leaf buds
All leaves are vegetative organs. With their help, the process of asexual reproduction is carried out. For example, if you separate a leaf of an uzambara violet from an adult plant and place it in a container of water, after a while it forms a root. But in a number of plants, the process of reproduction occurs differently. So, at the indoor Kalanchoe along the edge of the leaf blade there are kidneys, from which young shoots independently develop. They are almost completely formed: they have a small spine and leaves. Falling, they germinate in the same capacity as an adult plant. A similar process is also called self-propagation.
The value of plant leaf modifications is great. These devices increase vitality and facilitate the adaptation process. Thanks to leaf modifications, terrestrial plants were able to master various climatic zones, which differ in the level of moisture, temperature and soil properties. In addition to photosynthesis, transpiration and cellular respiration, leaf modification allows them to perform other important functions: protection against predators and mechanical damage, regulation of gas exchange and the level of water evaporation, and heterotrophic nutrition.