Anatomical structure of the camellia leaf. Camellia - flowering tea bushes
Content
plant description
How to care for the camellia growing in the house?
Location and light
watering
Temperature regime
top dressing
How and when to transplant a flower
How to propagate this flower culture?
Possible Growing Problems Plant Description
Camellia, a member of the tea family, is an evergreen shrub plant with bright colors. hallmark it is considered dense foliage with a glossy surface.
Already long time camellia, which came to us from Japan, is one of the most popular indoor flowers. Camellia can rightly be considered a model of perfection, as it has elegantly shaped flowers, painted in numerous shades, which harmoniously complement the juicy green foliage, as can be seen in the photo. And it is not surprising that the second name of the flower is Japanese rose.
Such a shrub can grow at home, reaching a height of about 1.5-2 meters. And in order for this plant to please with its beautiful flowering at any time of the year, it is necessary to create for it the most comfortable conditions. How to care for the camellia growing in the house?
There are several basic requirements that are recommended to be fulfilled so that the camellia growing in a house, apartment or on a veranda develops well, blooms, and is not affected by diseases. And you need to start caring for such a flower with correct selection places in the house for its cultivation. Location and light
The magnificent camellia belongs to light-loving plants. It is recommended to keep such a flower on the windowsills of the western and eastern windows, where there is a lot of scattered and bright light. But in the summer, as well as from exposure to direct sunlight, the shrub must be shaded.
In order for the formation of the crown at home to be carried out evenly, the flower should be periodically rotated around the axis. However, such procedures should be carried out only during the rest period. If you disturb the camellia at the stage of bud formation, it may not bloom at all, dropping all the buds. watering
Japanese rose, camellia, loves regular watering with uniform distribution of moisture over the substrate. The flower does not tolerate waterlogging well, so it is better to pour out excess water from the pan, and water the plant as the top layer of the soil dries up. For watering the plant, it is better to use soft water.
AT summer period(it coincides with the stage of laying buds) it is better to limit watering. At the same time add spraying, twice a day, also applying soft water. Competent care in terms of watering the camellia must be provided in winter. The Japanese rose should be watered much less frequently than usual to avoid root rot. Temperature regime
Not less than important point, which should include care, is the creation of an optimal temperature regime. Moreover, this flower does not belong to the heat-loving indoor plants. And for each season it is recommended to create an individual temperature:
in summer it should be readings from +20 to +25 degrees -
in spring (at the stage of bud formation) - this is + 13- + 17 degrees -
in winter - the thermometer readings of + 5- + 8 degrees will be optimal.
AT autumn period, as a rule, a fine cameo "falls into hibernation." And so that with the advent of spring she could give new shoots, it is worth keeping in the room where the flower grows, the temperature is about + 15- + 16 degrees. And also remember to limit watering, as previously mentioned. top dressing
Camellia needs to be fed only during the period active growth. Both organic and mineral fertilizers are used to fertilize such a Japanese rose at home.
As some flower growers have noticed, the flower responds well to fertilizers in the form chicken manure in low concentration. Before the onset of the bud formation phase, top dressing should be stopped. How and when to transplant a flower
Caring for camellia growing in domestic conditions does not bypass the process of transplanting it. Transplantation is not particularly difficult, but it has certain nuances.
For transplanting, you will need to prepare a new container and suitable soil.
As a substrate, oxidized soil diluted with humus is suitable. It is poured into a pot after a layer of drainage is laid out at the bottom. Suitable for growing camellias at home is considered the usual soil mixture intended for planting azaleas.
When transplanting too deep into the ground, the plant does not need to be sealed. Enough to arrange root system flower on the same level as the soil (see photo). A transplant is necessary for a camellia if the plant has grown noticeably and the current pot has become noticeably small. If the soil is hyperacidity, it is not suitable for growing camellias in it, and as a result, the foliage of the flower will begin to turn yellow and even fall off. In such cases, a transplant is also recommended. How to propagate this flower culture?
Camellia propagates in one of the following ways:
Seeds-
cuttings.
With the first method of reproduction, the flowering stage can be expected no earlier than in 5-6 years. And care should be more thorough. Therefore, this method is less popular, unlike the second.
With the help of cuttings, it is possible to have a camellia in 2 years, which will be ready for bud formation and flowering. Semi-lignified shoots of an adult plant are used as cuttings. It is recommended to cut them in May and early June. The suitability of shoots for use for propagation can be determined by their color, as a rule, they should be brown, approximately the same as in the photo.
A video clip containing tips from experienced flower growers will help you get acquainted in more detail with the breeding process of room camellia.
Potential Growing Problems
Camellia growing at home may be subjected to various diseases. Often the cause of the disease is inadequate care.
Diseases that can harm a plant include:
Oidium. This is a disease, the signs of which are appearing on the plant gray spots. As a treatment, treatments are carried out using a soap solution -
Cucumber mosaic, to which it is most susceptible japanese rose- camellia. You can recognize such a disease by the condition of the leaves - their veins will begin to turn yellow ( good example symptom in the photo). And as a means to help in the fight against such a disease, it is recommended to use insecticides -
Diseases are fungal, manifested in small spots of gray, black or brown on the foliage. Help in the fight against them drugs-fungicides-
Among other things, the plant needs to be cared for in terms of pruning. Such a procedure is carried out to activate the growth and development of axillary buds. A suitable period for pruning is the beginning of October - the end of November.
But it is worth remembering that camellia refers to poisonous plants. Therefore, all procedures for the care, transplantation and pruning of camellias at home should be carried out using gloves.
The location of tissues in the leaf, the degree of their development, the structural features of their cells vary greatly, which is due to both hereditary factors and plant habitat conditions. The anatomical structure of the leaf is extremely plastic and responds to changing conditions. external environment, especially on light and water regimes.
Task 3. Cross section of a leaf blade of a camellia leaf (Camelia japonica)
1. At a low magnification of the microscope, examine the cut of the leaf blade of the camellia leaf. Find the upper and lower epidermis, palisade and spongy chlorenchyma, sclereids, conducting bundles.
2. Schematically draw a section of a leaf blade with a central conducting bundle. Show the stomata in the lower epidermis.
3. With a high magnification of the microscope, draw a section of the transverse section of the leaf from the upper to the lower epidermis. Specify the upper and lower epidermis, stomata, cuticle, columnar and spongy mesophyll cells, calcium oxalate drusen and sclereids.
Explanation for the drug:
Camellia leaves are dark green, thick, leathery, shiny. On the transverse section of the leaf blade, it can be seen that the upper epidermis consists of small cells with thickened outer membranes, on the surface of which the cuticle is clearly visible. There are no stomata in the upper epidermis. They are located in the lower epidermis. Between the upper and lower epidermis is mesophyll(leaf pulp). It consists of 10-12 rows of cells. Under the upper epidermis are narrow cylindrical cells, elongated perpendicular to the surface of the leaf. These are living thin-walled cells with numerous chloroplasts. This fabric is called columnar (palisade) mesophyll. Between the cells of this mesophyll there are narrow, small intercellular spaces. spongy mesophyll consists of 8-10 rows of cells. These cells are irregular or round in shape. Between them is a system of cavities - large intercellular spaces. There are fewer chloroplasts in the cells of this mesophyll than in the columnar mesophyll, so the underside of the leaf is lighter than the top. On the cut are clearly visible conductive bundles different sizes. The largest one is leaf midrib. Xylem in bundles is always located to the upper side of the leaf, and phloem - to the bottom.. The bundle is surrounded by sclerenchyma in the form of a lining, which goes around the bundle from the phloem side. Among the mesophyll cells are sclereids(thick-walled cells of mechanical tissues (sclerenchyma) in plants) various shapes with thick lignified shells.
Stomata is a pore located on the lower or top layer the epidermis of a plant leaf through which water evaporates and gas exchanges with the environment. The pore consists of a pair of specialized cells called guard cells that regulate the degree of openness of the pore, and between them is the stomatal gap. The gap can expand and narrow, regulating transpiration and gas exchange. Under the gap there is a substomatal (air) cavity, surrounded by cells of the pulp of the leaf, through which gas exchange takes place directly. Air containing carbon dioxide ( carbon dioxide) and oxygen, penetrates into the leaf tissue through these pores, and is further used in the process of photosynthesis and respiration. Excess oxygen produced during photosynthesis by the inner cells of the leaf is released back into environment through the same pores. Also, in the process of evaporation, water vapor is released through the pores. The cells of the epidermis adjacent to the trailing cells are called accompanying (side, neighboring, parotid). They are involved in the movement of guard cells. Trailing and accompanying cells form a stomatal complex (stomatal apparatus). The presence or absence of stomata (the visible parts of the stomata are called stomatal lines) is often used in plant classification.
At aquatic plants a powerful system of air cavities is formed in the leaf. In plants of dry habitats (xerophytes), mechanical and conductive tissues are well developed. In shade leaves, the lack of illumination contributes to the formation of a spongy mesophyll with numerous intercellular spaces, thinning of the walls, epidermal cells and cuticle. In light leaves, bright illumination causes the development of a columnar mesophyll, a thick cuticle, thick-walled epidermal cells, etc.
Cross section of a leaf blade of a Camellia leaf (Camelia japonica)
Camellia represents evergreen shrub belonging to the tea family. Tea is made from the leaves of the Chinese variety of this plant. You can meet camellia in Vietnam, Japan and, of course, China. There are many garden and indoor varieties this decorative flower.
More about the flower
The popularity of camellia is due to the high attractiveness of both the shrub and the inflorescences. The plant decorates the room with both hot summers and cool winters. In the warm season, it pleases with its greenery, and in the cold, with beautiful and lush flowering.
flower care
Lighting
Decorative-flowering culture needs to provide daylight hours lasting up to 12-14 hours. It is impossible to place a camellia on the south side without shading, since the direct rays of the sun will leave burns on the plant.
The ideal option would be windows with a western and eastern orientation, where at noon there is no midday heat. Northern location does not allow providing the right amount light, and the flower begins to shrink, stretch.
Temperature
In spring and summer, camellia feels great with normal room temperature, but in autumn it should not be warm. It is best to take a flower pot to a terrace, a glazed loggia, any other place where it can be kept at a temperature ranging from 12 to 15 degrees.
The plant blooms even in frost. Optimal conditions counts temperature regime from +8 to +12 degrees. The room in which the camellia is located must be periodically ventilated to ensure a natural influx of fresh air.
Humidity
An exotic plant does not tolerate dry air. Room camellia needs to be provided high humidity. Especially in winter, when the flower is kept in a heated room. To create a comfortable microclimate, they resort to regular spraying, use humidifiers, use a tray with moistened moss or expanded clay, on which the pot is placed.
Watering
In summer, the soil in which indoor camellia grows is abundantly moistened, due to the rapid evaporation of moisture from the soil. In winter, watering is sharply reduced, even taking into account the fact that the plant blooms. Excessive stagnation of moisture in the soil leads to the appearance of pests and bacteria. To prevent this, the plant is watered when the earthen ball is dried.
Use boiled, settled or melted water. For supporting optimal acidity soil sometimes add acetic acid to the liquid or citric acid. A high concentration of various impurities and calcium salts negatively affects the condition of the flower, which must be taken into account.
Priming
Camellia prefers acidic soil with a pH level of 4.5 to 5. The flower can grow even in very acidic soils. Of the ready-made nutrient mixtures sold in stores, substrates for azaleas and rhododendrons are suitable. You can independently prepare the land from leafy, coniferous, peat land, taken in equal shares, with the addition of 0.5 parts of sand. The soil must be acidic, air and water permeable.
Circumcision
When the camellia completes its flowering, it is necessary to remove weak shoots. Pruning not only stimulates the plant to grow new branches, but also allows you to give the flower compact dimensions, form a tree or bush. Shoots are allowed to be removed half. If woody branches are removed, the cuts are processed with a garden pitch.
top dressing
Decorative flowering culture during the growth of young shoots, which falls on the spring months, needs fertilizer. Feed camellia one every 14-30 days, using complexes for azaleas. The concentration indicated in the instructions for the drug is reduced by half. You can not take complexes with magnesium and calcium. An excess of the latter leads to the fall of the buds. From July to spring, the flower is not fertilized.
Transfer
Young indoor camellia is transplanted annually at the end of winter or autumn. Large bushes are transferred to a new container every two to three years, when the root system fills the old pot. They carefully monitor that the neck is above the level of the earthy coma, that is, it is open. If such a need arises, they fill up with fresh earth, carry out mulching with sawdust to increase the acidity of the soil.
reproduction
Camellia is often grown from seeds that are large in size, covered with a strong shell. To make them germinate faster, they are doused with boiling water, and then slightly pierced sharp knife. The seeds are planted in cups with a diameter of 7-10 cm, 2/3 filled with peat soil, 0.5 cm of soil and 1 cm of perlite are sprinkled on top. You need to make sure that the part with the eye is at the bottom.
Picking is carried out after the formation of at least a pair of leaves. When the area allows, the sprouts can be immediately planted in separate pots. After 2 weeks of planting, they are fed with a fertilizer that stimulates growth. Picked plants are transplanted into permanent containers when the cups are filled with the root system.
To preserve varietal characteristics, it is recommended to propagate camellia by cuttings. Saplings, having a length of 6-8 cm and 2-5 leaves, are cut from the upper green shoots. The leaf plates are cut off by half, the planting material is placed in Kornevin, and then in pots with a substrate of peat and sand, taken in equal proportions. A month later, when the cuttings take root, they are transplanted into permanent pots.
Diseases and pests of camellia
Camellia rarely causes trouble for the grower, but if the microclimate is disturbed, the plant weakens.
Diseases
The flower rarely gets sick and is mostly vulnerable to:
When the plant is damaged by fungi, the petals turn brown, the leaves become stained, and the inflorescences fall off. If the treatment with fungicides does not lead to an improvement in the condition, the flower can no longer be saved.
Pests
The main enemies of room camellia are:
- Mealy worm. The pest is removed with a cloth soaked soapy water. If only a few leaves are damaged, they can simply be cut off. Treatment with Karbofos (20 drops per 1 liter of water) is carried out in extreme cases.
- Aphid. Causes yellowing and wrinkling of the leaves. Adult aphids are removed mechanically at intervals of several days. Special aerosols facilitate this process.
- Spider mite. The most gentle and safe way get rid of the pest is spraying oil emulsions that are sold in flower shops.
- Skosar. He likes not the above-ground, but the underground part of the camellia. If insecticide treatment is not carried out in a timely manner, the plant will die.
- Shchitovka. Leads to blackening and brown tubercles on the leaves. Pests are removed manually, but only insecticides can completely get rid of scale insects.
Camellia varieties for home cultivation
For indoor maintenance, the following varieties of room camellia are most often chosen:
From any indoor camellias you can form a compact bush or tree.
Questions and answers
- Why do leaves and shoots of camellia turn brown?
If, along with a change in the color of the green mass, the plant sheds buds, the soil is excessively waterlogged. To remedy the situation, you need to reduce watering. - Are the leaves turning brown?
A similar situation is typical for sunburn. If you shade the flower, the camellia will again gain a good and healthy green mass. - Has the camellia shed its leaves?
Falling leaves - main feature insufficient watering. Along with the revision of the soil moisture schedule, you need to pay attention to air humidity. If it is too low, the moisture will evaporate quickly.
Camellia (Camellia) is evergreen belonging to the Tea family. This amazing flower was named after the Jesuit monk Kamelius Georg Joseph, who first brought it to Europe. In conditions wildlife the plant grows in tropical, subtropical zones in countries such as Japan, Korea, Malaysia, the Philippines, India, China, on the islands of Java, Sulawesi.
Surely the description of the camellia flower will be of interest to many florists. This is beautiful plant is a shade-tolerant bush or tree, the height of which can vary between 2 - 20 m. Dull or pointed leaves have a simple, elliptical, broadly or oblong-ovate shape, leathery structure, glossy surface, short petioles. They are single, sequential. Length sheet plate is about 3 - 17 cm.
Getting an answer to the question of what a flower of a plant looks like is a must. Camellias form many single buds. The diameter of blooming flowers with numerous stamens can vary within: 1 - 12 cm. At the base, the petals are fused. Their color is pink, red, white, variegated.
Popular types of camellia
Modern breeders have bred numerous varieties, camellia hybrids, based on various varieties plants. Below are the most popular types.
camellia japonica
This variety is considered the most famous, often used in breeding events to breed indoor flowers. In the Land of the Rising Sun given plant revered on a par with the iconic sakura. The magnificent flower Japanese camellia (Camellia japonicaa) is cultivated as indoor, greenhouse, garden. It is often used as an interior decor, for making bouquets.
AT natural conditions the plant can have a height of 1.5 - 11 m. Caring for home care for Japanese camellia, you can expect to receive tree shrub with stems up to 1 m long, flowering in November - January. Semi-double, double spherical flowers may have white, pink, red colors. In hybrid specimens, the petals often have a spotted or striped color. Flowers form in leaf axils and cover the entire crown.
camellia sinensis
This variety has another name - tea bush. The leaves of the plant are used to produce green, black, long leaf tea. Dried flowers are components of various aromatic additives.
If you are interested in the question of where the Chinese camellia (Camellia sinensis) grows, you can find out that the industrial cultivation of the plant is carried out by many countries: China, India, Kenya, Japan, Georgia, etc. Our state is also engaged in the cultivation of tea camellia ( Krasnodar region). Indoors, its cultivation is carried out quite rarely.
mountain camellia
Mountain camellia (Camellia sasanqua) in nature grows on the islands of Kyushu, Okinawa (Japan). In a cool room, it is fashionable to observe its flowering in the period November - February. The view is often taken as the basis for the derivation of indoor, garden varieties. The plant forms single buds or rosettes with 2-3 flowers. The red camellia flower looks very impressive, also, the petals can be white or pink.
camellia saluyonskaya
This species is actively used in breeding cold-resistant varieties suitable for garden and greenhouse cultivation. A slightly branched shrub reaches a height of 1.5 m. Large flowers (8 cm in diameter) gradually bloom on it, the color of which can be snow-white, pink, dark red, burgundy. Saluyon camellia (Camellia saluenensis) is considered the most unpretentious of garden plants of his family.
Camellia oleifera
Cultivating it evergreen tree a height of about 10 m is practiced in Chinese mountainous areas. Large seeds of the camellia oil (Camellia oleifera) flower are formed in a large fruit box. For single bisexual or paired axillary flowers, the presence of a white color is characteristic.
Indoor camellia: cultivation and reproduction
As practice shows, home care for a camellia flower, which is quite capricious, will be very successful if a number of rules are observed. To master the skills of growing such a plant is quite within the power of any grower.
Requirements for location, lighting
So that the home maintenance of camellia does not cause problems, you will initially need to decide on the most successful place to install a pot with a plant.
For this purpose, it is worth giving preference to windows oriented to the west or east. Camellia also feels great in winter garden, greenhouse, on a glazed loggia.
An inexperienced florist caring for and propagating a camellia flower should take into account that the plant (especially in the first year after planting) does not like moving, turning the flowerpot, being exposed to direct sunlight, and drafts.
A new flower bought or donated must be kept in a shaded cool room for 2 weeks, and then transferred to a permanent sunny place, where the temperature will not exceed + 16 ° C.
In the summer, the plant is allowed to be put on Fresh air with obligatory shading. Beautiful flower camellia in a pot will demonstrate good growth, the development of buds in diffused lighting lasting 12 - 14 hours per day. AT cold period year it is worth providing camellias with additional illumination.
Temperature regime for the plant
During the laying of flower buds, it is necessary to provide for maintaining a temperature of + 5 ... + 6 ° С. Best flowering the plant will demonstrate at + 8 ... + 12 ° C. In the dormant phase, camellia tolerates temperatures + 20 ... + 25 ° C well.
Organization of watering camellia
When deciding how to care for a camellia flower, you will need to ensure that it is regularly watered using settled water. During budding, flowering, irrigation is carried out immediately after the drying of the upper soil layer is detected. It is very important to prevent stagnant water, acidification of the earth. In the dormant stage, moderate watering should be dispensed with.
To increase the humidity of the air on hot days, it is recommended to spray the bush twice a day. Also pouring water into the pan has proven itself well. Justified will be the installation of the pot in a container filled with moistened gravel, moss, sand or pebbles.
The plant likes acidified water lemon juice, vinegar. With a lack of moisture, the bush is able to shed its leaves. Excessively abundant irrigation can provoke a situation where the leaves and stems of camellias turn brown. Subsequently, flowers and buds may fall off the plant. If the situation is not corrected, the flower will die.
Soil quality for crop
Camellia is very demanding on the quality of the soil. She feels best when planted in acidic soil with a pH level in the range of 3 - 5. The use of a soil substrate for azaleas has proven itself well. Self-cooking soil mixture involves the use of turf (1 share), sand (1 share), peat (2 shares), leaf ground(2 beats).
Transplanted shoots are best placed in a flowerpot filled with a substrate with the following composition: sand (0.5 shares), peat (1 share), coniferous soil (2 shares). At the bottom landing capacity drainage must be provided.
Performing top dressing camellia
Camellia responds positively to organic fertilizers. In the autumn-spring period, monthly application is practiced. liquid dressings. During budding, flowering, this event is performed 2 times a month. For camellia it is desirable to purchase ready-made fertilizers suitable for orchids, azaleas.
Pinching and pruning the plant
In order to prevent crushing of flowers, pinch the buds, leaving a maximum of 2 copies per branch.
In autumn, the plant is pruned. Damaged, weak shoots are removed from him. This activates the formation of axillary buds.
The procedure for transplanting to another pot
Camellia undergoes an annual transplant for the first 3 years, and an adult, well-flowering bush - every 2 years. A similar procedure is carried out after the flowers wither in spring or summer, while pinching the apical sections of the shoots.
Reproduction of camellia in different ways
When propagating the camellia flower, it is advisable to give preference to the cutting method.
To get high-quality planting material, you need to trim the apical shoots that have formed over the current season. The recommended length of the cuttings is 6-8 cm, they should have 4-5 leaves. An oblique cut over the axillary kidney is practiced.
The optimal months for vegetative breeding of a plant are January, July-August. The rooting of summer seedlings will take about 2 months, winter seedlings will form a root system over a longer period.
The cuttings are planted in boxes filled with a mixture of peat (1 share), sand (1 share). The containers are to be installed in a bright room with the temperature maintained at + 20 ... + 23 ° C, the soil is moistened by spraying. Germinated specimens are determined in pots with a diameter of 7 - 8 cm.
Florists with experience practice growing camellias from seeds to simultaneously obtain a large number young bushes. As part of this procedure, each seed is sown in a separate container. The 2 true leaves that have appeared are a signal of the need to pick the plants into a larger container.
It should be noted that often flower shops may offer a mixture of seeds for sale different varieties. In order not to subsequently encounter a solution to the problem of how to care for camellia mix, you will first need to carefully read the information published on the package. The preferred choice is planting material certain variety, hybrid.
Garden camellia: care features
Experienced florists are sure that keeping a camellia flower in the garden is guaranteed not to be problematic for a person who has studied the appropriate agricultural techniques. Transfer young plant in open ground conditions it is produced every two years, an adult culture is transferred to a new place with a frequency of 5-7 years.
AT landscape design, basically, the garden curly camellia flower is used. In regions with severe winter period to grow in open field many small varieties have been bred. In anticipation of frost, they are transplanted into flowerpots and transferred indoors.
Diseases, crop pests
Unfortunately, camellia in the open field, like indoor flower, often becomes the object of attack by pests such as aphids, scale insects, whiteflies, worms, spider mite, thrips.
The appearance in the leaf axils, in the areas of the stems of a white, dense coating indicates the defeat of the plant by the mealybug. To get rid of the pest, it must be removed with a cotton swab, toothpicks, and then wipe the affected areas with a sponge dipped in a solution of laundry soap.
Due to aphids and scale insects, sooty spots begin to be visible on the plant - the black camellia looks very unpresentable. Heavily damaged specimens must be treated with specialized fungicides, insecticides. Blackened leaves must be removed.
Brown, gray spots on the sheets signal a fungal infection. Yellowing veins on the surface of the leaves indicate a mosaic virus. Having identified the disease in time, it is urgent to take up the treatment of the plant, because otherwise decorative properties camellias will be lost for a long time, and sometimes the flower may even die.
Reward for patience and hard work
Anatomical structure camellia leaf
(Camellia japonica)
Examine a section of a camellia leaf at low magnification and note that the outside of the leaf is covered with epidermis. Between the upper and lower epidermis is a tissue that consists of cells containing chlorophyll. This is the assimilation parenchyma - mesophyll. Between the cells of the mesophyll at some distance from each other are vascular fibrous bundles.
Then move on to a detailed examination of tissues at high magnification. Start by looking at the top epidermis and compare it with the bottom. The main features: a thicker outer wall, a more powerful cuticular cover and the almost complete absence of stomata on the upper epidermis.
Fig.13.1. Camellia leaf in cross section: 1 - upper epidermis,
2 - columnar parenchyma, 3 - spongy parenchyma, 4 - cell with druse, 5 - sclereid, 6 - vascular bundle, 7 - lower epidermis,
8 - stomatal apparatus
Note that in the upper epidermis the cells have elongated shape, densely closed, without intercellular spaces, arranged in two layers. This is columnar(palisade) parenchyma. This is where photosynthesis takes place. At the lower epidermis there are more rounded cells with large intercellular spaces - spongy parenchyma. Leaves in which the mesophyll is differentiated into columnar and spongy parenchyma are called dorsoventral. The main function of the lower side of the leaf is gas exchange and transpiration. Carefully examining the spongy parenchyma, one can notice calcium oxalate druses in some cells, as well as large branched mechanical cells - sclereids(idioblasts) that perform a supporting function.
The structure of the vascular-fibrous bundle is best seen on the main vein, since with an increase in the order of branching, the bundle becomes atypical. The main vein occupies almost the entire thickness of the leaf from the upper to the lower epidermis. At low magnification, a powerful xylem is clearly visible, consisting of regular rows of conductive elements that alternate with wood parenchyma. The phloem is adjacent to the xylem. It is noted that the xylem is facing the upper side of the leaf, and the phloem is facing the bottom. The bundle is surrounded by sclerenchyma. The sclerenchymal lining consists of a single layer of thin-walled cells that do not contain chloroplasts. It separates the bundle from the mesophyll. Above and below the bundle is collenchyma adjacent to the epidermis. Thus, it is a closed collateral vascular fibrous bundle.