Modification of plant leaves

Each part of the plant performs its basic functions based on the characteristics of its structure. But the modification of leaves, as well as other necessary organs, allows them to purchase additional ones. Most often, they depend on the climate and conditions of growth.

Modifying the leaves of the tropics

Plants of moist equatorial forests are very easy to find out - according to the characteristic shape and dimensions of their leaf blades. In the tropical climatic zone, their tree forms occupy a dominant position, allowing only shade-tolerant bushes and grasses to live. Leafy plates of such plants are unusually large and wide. How to explain such a 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 the leaf. The larger the area of the plate, the more intensive the gas exchange with the surrounding medium. And in conditions of high humidity it is simply necessary to prevent rotting processes.

Spines

The spines are also plant leaf modifications. They are characteristic of those of them that grow in arid and desert conditions. Everyone saw the spines of a cactus. This is his leaves. In conditions of lack of moisture, when the process of transpiration should be minimized, it is an ideal device. With such a small surface of the leaf blade and water evaporate very little.

However, the spines of the cactus and acacia are a different modification of the leaves. What's the Difference? In white acacia, hawthorn, thorn, barberry 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 eating by various animals.

Hvoinki

The modification of the leaves is also the needles of all representatives of the gymnosperm plant. Everyone remembers the children's riddle about the Christmas tree - "in winter and summer in one color." And evergreen all coniferous plants are in many respects precisely due to the characteristic alterations of the leaves. On the cross-section, they have a round or ribbed shape. These leaves have a small area, like thorns of cacti. Their stomata, through which gas exchange occurs, are immersed in the integumentary and the main part of the leaf. This reduces the level of evaporation of water. In winter, these formations are completely sealed with wax, which reduces transpiration to almost zero. Therefore, at the time when all angiosperms shed their leaves for the winter, coniferous trees and shrubs can boast of luxuriant green decoration.

Leaves of desert plants

It is not easy to survive in arid conditions. What causes changes in the leaves of these plants? They need to have such features of the structure that will survive with sudden temperature changes and a lack of moisture. Therefore, the leaves are often covered with a thick layer of hairs, or wax coating. They protect plants from excessive loss of moisture. There is another device. Many species of arid ecosystems accumulate a reserve of water in thickened, fleshy leaves. An example of this modification is aloe, which is often bred as a houseplant with healing properties.

Antennae

In order to consider the peculiarities of the following organs, let us recall what changes in the leaf occur in the family of legumes. The shoots of most of them are long and thin, and the fruits acquire a mass during maturation, which does not allow them to remain in the vertical position. But it is the most beneficial for the productive implementation of photosynthesis. What kinds of leaf changes occur in peas? Of course, this is the antennae. Thus, individual plates from a complex sheet are modified . With their help, the plant clings to the support, and as a result, the weak and thin stem is located in the required position.

Scales

To understand why the renal scales are a modification of the leaf, it is necessary to understand the structure of the bulb. Consider it with the example of ordinary leeks. Its bulb, despite the fact that it is located under the ground, is a modification of the aboveground part of the plant - escape. This is easy to prove. Escape consists of a stem, leaves and kidneys. The same parts are in the bulb. Its flat stalk is called the bottom. A bundle of subordinate roots departs from it. Above are several kinds of leaves. Young have a green color and grow from the kidneys located on the bottom. Juicy and fleshy leaves acquire this kind in order to store moisture. With its help, plants that form a bulb, under the earth suffer a drought, low temperatures and other adverse events. And from mechanical damage, the inner contents of the bulb are protected by dry scales, which are also a modification of the leaves.

Predatory leaves

The modification of the leaves is also very dangerous for other living things. There is a whole group of insectivorous plants. They are also capable of carrying out the process of photosynthesis, that is, they are autotrophs. But if there are no conditions for its flow, then they pass to the heterotrophic method of nutrition. With the help of modified leaves, they catch insects and digest them. For example, in a tropical sarrachenia plant, the leaves are a funnel that fringes the fragrant nectaries. They attract insects. Approaching, the victim begins to glide along the edges of the funnel and is trapped. In addition, the leaves also produce 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 the rain to get inside, mixing with digestive enzymes.

Changes in the leaves include mobile tentacles of sundew, with a sticky liquid at the ends of the tentacles. It attracts insects that land down to eat and are trapped.

Leaf buds

All leaves are vegetative organs. With their help, the asexual reproduction process is carried out. For example, if you separate the leaves of the vampire violets from an adult plant and put them in a container of water, after a while it forms a root. But in a number of plants the process of reproduction is different. Thus, in the room kalanchoe along the edge of the leaf blade there are kidneys, from which young shoots develop independently. They are almost completely formed: they have a small spine and leaves. Falling, they sprout in the same capacity as the adult plant. A similar process is also called self-propagation.

The significance of plant leaves' modifications is great. These adaptations increase the viability and facilitate the adaptation process. Due to the modification of leaves, terrestrial plants were able to master various climatic zones, differing in the level of moisture, temperature regime and soil properties. In addition to photosynthesis, transpiration and cellular respiration, leaf alterations allow them to perform other important functions: protection from predators and mechanical damage, regulation of gas exchange and evaporation of water and heterotrophic nutrition.