Plants which reproduce by vegetative propagation

This procedure is possible in 4 different ways:. Tissue Culture - When natural conditions are not comfortable for a plant to grow, then this method is highly useful. With the help of a technician, the respective parts of a plant are segregated and cultured in a clinic. This way, one can develop rare and extinct cases of plant species effectively. Potatoes and sugarcane are produced through tissue culture propagation. Grafting - This is an artificial method of propagation, wherein a plant is first rooted deep into the ground.

The cut part from another plant is attached and connected to the stem of the former. The tissues of both the rooted plant and the graft get interlinked and produce a new plant variant.

Apples and pears grow by this means. Cutting - A part of the plant is cut and rooted in the soil, most commonly the leaf or stem. A new plant will develop from these cut roots, which is called the adventitious roots. Sometimes hormones growth promoters are injected into the contents for nurturing and inducing quick plant development. Roses grow in this method. Layering - The layer is the part that will produce new plants.

The covering soil helps in the growth of adventitious roots, thus forming plant variants. Honeysuckle, boxwood, wax myrtle are some of the examples of layering propagation. Rhizomes are root-like stems that grow horizontally under the ground. New roots and shoots form at the nodes with shoots growing upwards to form new plantlets. Lateral buds grow out to form new rhizomes. Examples include iris and root ginger. Stolons or runners are horizontal stems that grow above the ground, for example, strawberries.

Tiny plantlets form along the stolon , and roots form where they touch the ground. When the connection with the parent plant breaks, the new plant becomes independent. Tubers are swollen portions of an underground stem that store food so a plant can lie dormant over the winter, for example, potatoes. These methods involve taking a piece of one parent plant and causing it to regenerate itself into a new plant.

A cutting is a piece that has been cut off a mother plant and then caused to grow into a whole plant. Often this involves a piece of stem that is treated with hormones to encourage new roots to form before planting.

Sometimes root cuttings with buds on them will produce new shoots when pressed directly into soil. This method involves joining a stem piece as in grafting or a single bud as in budding onto the stem of a plant that has roots.

The stem piece or bud is called the scion, and the plant with roots is called the rootstock. Grafting is commonly used to produce fruit trees sometimes with more than one variety of the same fruit species growing from the same stem. Grafting and budding are standard techniques used for propagating new apple cultivars.

Using tissue culture, sometimes called micropropagation, tiny fragments of plants are treated with plant hormones in a sterile growing medium.

The hormones stimulate the growth of a callus, from which a new seedling can grow. This method is used to produce large numbers of identical seedlings. In the interactive Making a transgenic plant , the third step shows how transgenic plantlets are developed in the lab using tissue culture and then grafted onto rootstock. The life cycles and life spans of plants vary and are affected by environmental and genetic factors.

The length of time from the beginning of development to the death of a plant is called its life span. The life cycle, on the other hand, is the sequence of stages a plant goes through from seed germination to seed production of the mature plant. Some plants, such as annuals, only need a few weeks to grow, produce seeds, and die. Other plants, such as the bristlecone pine, live for thousands of years.

Some bristlecone pines have a documented age of 4, years. Even as some parts of a plant, such as regions containing meristematic tissue the area of active plant growth consisting of undifferentiated cells capable of cell division continue to grow, some parts undergo programmed cell death apoptosis.

The cork found on stems and the water-conducting tissue of the xylem, for example, are composed of dead cells. Plant life spans : The bristlecone pine, shown here in the Ancient Bristlecone Pine Forest in the White Mountains of eastern California, has been known to live for 4, years.

Plant species that complete their life cycle in one season are known as annuals, an example of which is Arabidopsis , or mouse-ear cress. Biennials, such as carrots, complete their life cycle in two seasons. Commercial growers harvest the carrot roots after the first year of growth and do not allow the plants to flower.

Perennials, such as the magnolia, complete their life cycle in two years or more. In another classification based on flowering frequency, monocarpic plants flower only once in their lifetime; examples of monocarpic plants include bamboo and yucca.

During the vegetative period of their life cycle which may be as long as years in some bamboo species , these plants may reproduce asexually, accumulating a great deal of food material that will be required during their once-in-a-lifetime flowering and setting of seed after fertilization. Soon after flowering, these plants die. Polycarpic plants form flowers many times during their lifetime. Fruit trees, such as apple and orange trees, are polycarpic; they flower every year.

Other polycarpic species, such as perennials, flower several times during their life span, but not each year. By this method, the plant does not require all its nutrients to be channeled towards flowering each year.

As is the case with all living organisms, genetics and environmental conditions have a role to play in determining how long a plant will live.

Susceptibility to disease, changing environmental conditions, drought, cold, and competition for nutrients are some of the factors that determine the survival of a plant. Plants continue to grow, despite the presence of dead tissue, such as cork. Individual parts of plants, such as flowers and leaves, have different rates of survival. In many trees, the older leaves turn yellow and eventually fall from the tree.

Leaf fall is triggered by factors such as a decrease in photosynthetic efficiency due to shading by upper leaves or oxidative damage incurred as a result of photosynthetic reactions. The components of the part to be shed are recycled by the plant for use in other processes, such as development of seed and storage. This process is known as nutrient recycling. However, the complex pathways of nutrient recycling within a plant are not well understood. The aging of a plant and all the associated processes is known as senescence, which is marked by several complex biochemical changes.

One of the characteristics of senescence is the breakdown of chloroplasts, which is characterized by the yellowing of leaves. The chloroplasts contain components of photosynthetic machinery, such as membranes and proteins. Chloroplasts also contain DNA. The proteins, lipids, and nucleic acids are broken down by specific enzymes into smaller molecules and salvaged by the plant to support the growth of other plant tissues.

Hormones are known to play a role in senescence. Applications of cytokinins and ethylene delay or prevent senescence; in contrast, abscissic acid causes premature onset of senescence. Plant senescence : The autumn color of these Oregon Grape leaves is an example of programmed plant senescence.

Privacy Policy. Skip to main content. Plant Reproduction. Search for:. Asexual Reproduction. Asexual Reproduction in Plants Plants can reproduce asexually, without the fertilization of gametes, by either vegetative reproduction or apomixis.