Tropical orchids, unlike other plants, are made up of roots, stems, leaves, flowers, fruits and seeds, working together to grow and develop in each stage.
Features of tropical orchids
Tropical orchids in the botanical classification belong to the orchid family (Orchidaceae), based on morphology can be classified into 2 types: the biogenous orchid and the epiphytic orchid. Secondary orchid refers to orchids with live air roots clinging to dry tree trunks or lava to grow, such as Cat Lan, Ho message orchid, Cymbidium, Hoang Thao orchid, Van Lan. Only orchids grown in the ground contain a lot of organic matter, such as orchids Comedy, orchids Hac Dinh (Phainus) ... Tropical orchids are not like other plants, plants are made up of roots, stems, leaves, flowers. , fruit and seed, do the task of growth and development in each stage.
Orchid vanda - Tropical orchid
Roots of tropical orchids:
The roots of tropical orchids, whether they are air or underground roots, are large, usually round cylindrical, or round, with the white outer layer of the roots, absorbing nutrients in water and air. . Parts with pointed green color (orchid appendage) or parts with brown color (phylogenetic orchid) is the top part of the roots, in addition to its absorption effect, it also functions to prolong the growth and fabrication. portion nutrition. The root tip is extremely sensitive to the external environment, if exposed to fertilizers and pesticides too concentrated, they are very susceptible to damage. The succulent root layer is filled with water to absorb water and retain water, and also to protect and prevent drought. The innermost layer of the roots is the central pillar, a very strong organization that fixes the trunk.
There are many organizations in the roots of tropical orchid plants, in the roots contain a symbiotic living bacteria, this orchid fungus after penetrating inside the roots in the form of mycelium, is gradually broken down and digested, the nutritional composition. The nutrient is absorbed by the cells of the orchid, providing for the vegetative tropical orchid. At present, this symbiotic mycorrhiza has a very important effect on the nutrient absorption of the air roots when sub-propagating, because the air roots cannot absorb nutrients directly in the air, but can only rely on the mycelium fixates nitrogen gas in the air, providing seedling growth in the legume family. In addition, the seeds of the orchid plant only have embryos that do not provide nutritional components, the embryo for seeds germinates, in the natural world if this mycelium does not penetrate, providing nutrition for the embryo, the plant Small orchids cannot thrive.
Stems of tropical orchids:
In terms of morphology, the trunk of tropical orchids can be classified into two large types, namely multicamera and single. Polymorphic tropical orchid refers to a limited maturity of its body (main body), its elongation based on new branches, (sub-branch) is produced continuously every year, for example Cat Lan. , Cymbidium, Lan Hoang Thao ... Single tropical orchid refers to the elongated maturity of its main body (main axis) as a result of the growth of tops, for example, Van Lan, orchid Phuong Vy ...
The stems of tropical orchids are like a stake, supporting leaf blades, flowers and transporting water and nutrients. Some trees with bulging stems have the function of storing water and nutrients called practitioners, such as Cat Lan, Hoang Thao ... On the contrary, the trunk of Van Lan has long stems and has hardwood material. Its nutrient and water reserves are both dependent on large, fatty leaf blades. In addition, the stems of moth orchid and slipper orchid are very short, vulnerable to human carelessness and disease, and the plants grow and flower normally every day. So when you want to plant, you need to pay attention to protect and keep the stem from being damaged.
Leaves of tropical orchids:
The leaves of tropical orchid are different based on different species, for example, the leaves of Cat Lan are oval, the leaves of Ho Diep orchid have the shape of large, round, succulent eggs ... Usually those types grow under the conditions. with enough light the blade is hard and greenish yellow. For those that grow in shady conditions, lack of light, have broad and soft leaves, the color of the leaves is dark green. Therefore, we can base on the nature, shape and color of the leaf blade to judge the amount of light that this tropical orchid needs, thereby adjusting the light so that it is suitable for planting. plants grow normally. The leaf blade of a tropical orchid is made up of the upper cuticle, the leaf flesh and the lower epidermis, whose leaf flesh is not the same as the leaves of other plants, has a shack shape and a clear porous structure, formed by closely arranged chlorophyll-containing cells. There are very few openings of cells, the epidermis is formed by small cells that do not contain phytoplankton arranged together to form, the outer surface has a protective layer of horny. There are some types with thick, succulent cuticles, which are able to withstand high temperatures and intense sunlight, and at the same time, is also very good at drying, the color of the lower cuticle is lighter than the layer. upper epidermis, pale green or yellowish green in color, with multiple pores, to regulate water evaporation and exchange of oxygen and CO2. Many types of tropical orchids, the air holes on the blade close during the day, open until night, inhale CO2 and release oxygen, conduct the plant metabolism (Crassulacean acid metabolism - CAM), to save water, ensure the requirements when performing photosynthesis during the day. For this type of tropical orchid with CAM process, like succulent plants, it is able to withstand strong dryness, and still grows normally in hot sunny conditions. For example, Van Lan looks widely in Laos, Cambodia to cut flowers, is grown all day under intense sunlight to stimulate more flowers and beautiful flowers.
What are the characteristics of tropical orchids?
The flowers of tropical orchids are the focal point of enjoyment. The size of the flower depends on the type, for example Cat Lan, the diameter of the single flower is up to 18cm. Meanwhile Hoa Hoang orchid (Ascocentrum miniatum), flower size only 0.5cm. In terms of the color of flowers, the richer and more diverse, except only black color is not available, there are almost all the colors of the natural world, from pure white, yellow, orange, vermilion, pink. to green, purple, blue ... all have. The structure of tropical orchids is similar to that of other orchids, each flower is made up of the following parts:
Petals: usually there are 3 petals, located in the inner ring, 1 pair of two symmetrical sides called petals, located on the lower side of the center, the outer shape is different from petals on two sides called lip petals. The shape of the lip wing is very diverse, there are species like lilies, such as the purple-red lips of the crane orchid, there are species like girls, gentlemen, like the yellow lips of the Orchids. pea pod or bag, such as an orchid. The lip is the main unique part of the orchid, with various shapes, rich and beautiful colors, is the main organ that attracts insects to spread pollen.
Calyx: Calyx is usually shaped like a petal and has a beautiful color. Especially some flowers such as Van lan, Hai Lan, its calyx are more developed and beautiful than petals, becoming the focus point. Calyx usually has 3 petals, located in the outer ring, during the bud, the calyx embraces the petals, which protects the petals. The parts located at the top are called the top scaffold, the parts located on both sides are called the sub-scaffold.
Stigma: Also known as the pistil, is a reproductive organ made up of the male and female stamens together. It is located at the center of the flower, above the lip, by a male stigma, a stalk end, and a mouth pistil together. The top of the stalk is the anther, which contains a "T"-shaped pollen in the center of the pollen stand. In addition, the bottom of the anther has a concave trough, inside there is a lot of sticky fluid, easy to stick to the pollen that insects accidentally bring to pollination.
Fruit of tropical orchids:
The tropical orchid is called the squirrel fruit in terms of botany. Usually long strip or ovoid, with many stalks at the top. The outer surface of the fruit usually has edges, the inside has a multitude of small particles like dust, for example, Cat orchid in a fruit has up to 1 million - 1.5 million seeds, even an ordinary tropical orchid there are also 100 thousand - 300 thousand seeds. When the ripe fruit cracks on its own, the seeds bounce off and fly with the wind. Under manual planting conditions, the seeds that can self-germinate are very few, only those seeds that are not contaminated by in vitro bacteria can grow certain seedlings.
Seeds of tropical orchids:
The seeds of tropical orchid are as small as dust seeds, with a length of only 0.1 - 1mm, the length of the dragon is only 0.05 - 0.5mm, because 1 embryo is greenish yellow or brown yellow, the oval around the seed shell is formed by 1 - 2 cell layers. Because the embryo does not contain an embryo, it is impossible to germinate without the symbiotic fungus or the germination agent supplied by the grower. Therefore, when the fruit cracks, the falling seeds rarely germinate, only a few of the seeds flying in the wind cling to the tree's hammock or between rocks, at the same time, can get the nutrition from the symbiotic fungus to germinate. leaf out.