Understanding the Process of Plant Tissue Culture
While plant tissue culture turns one single plant with the desired features into hundreds and thousands of plants within one year, the process is achieved in three stages by exposing plant tissue to a specific medium of nutrients, light and hormones maintained under sterile vitro conditions. Some of the distinguishing features of the plants evolved through this technique include disease or pathogen-free state, healthier and more fibrous root system, dense branching and more survival rate.
The three main stages in developing individual plants from plant tissues can be detailed as follows:
STAGE I or the initiation phase is concerned with the placing of plant tissue in vitro after sterilising the material and initiating the process of tissue culture.
STAGE II refers to the phase of multiplication in which the in vitro plant material undergoes re-division and is established in a medium containing plant growth regulators that are known to induce the proliferation of multiple shoots. The process accomplished in this stage is repeated a number of times until it results in the number of plants desired.
STAGE III is called the root formation phase. It refers to the process of introducing appropriate hormones to trigger rooting and to achieve the formation of complete plantlets.
One the plants are subjected to these three stages, the plants are shifted from the laboratory to the greenhouses for acclimatizing them and to enable further development.
Uses and Applications of Plant Tissue Culture
Today, plant tissue culture has a wide range of direct commercial applications besides holding immense value in the research arena of cell biology, biochemistry and genetics. Some of the most popular techniques in the field include culturing cells, embryos, anthers and ovules both in experimental and industrial scales. Some of the other notable processes in the field are isolating protoplast and fusion, cell selection and culturing of buds and meristem.
Some of the most important applications of plant tissue culture are micro-propagation with the help of meristem and shoot culture to develop huge numbers of individuals that are identical to each other and screening the programs of cells as against the conventional method of screening plants in search of advantageous characteristics. In addition, the process also finds its application in growing plant cells in liquid culture in a large scale to be used as sources for secondary products, using the method of protoplast fusion to cross species of plants that are distantly related, regenerating dihaploid plants from haploid cultures to secure homozygous lines quickly during breeding programs and removing viruses by propagating meristematic tissues.
Plant tissue culture today has undergone a phenomenal development. During the recent past, this technique has been fruitfully applied to the breeding and propagation of trees and shrubs. There are a number of firms that are applying this technology for commercial scale propagation of apples, rhododendrons, crabapples and a number of other woody species. This technology has been extensively used in the development of new varieties and commercial breeding of ornamental plants. Thus, tissue culture has established itself as one of the most potential tools for propagation. The most popular arenas which plant tissue culture has completely taken over today include micro-propagation and controlled management and treatment of plants in the cellular level.
â€˜Micro-propagationâ€™ is the term that best conveys the essence of tissue culture technique widely found in application today. While the prefix “micro” talks of the small size of the tissue gathered for propagation, it also equally refers to the size of the plants that are evolved out of this process. The technique of micro-propagation enables the breeding of a huge number of plants from small pieces of source plants within an unbelievably short period of time. Depending on the species of plant considered for the process, the source tissue can be gathered from one of the plant parts including leaf, root tissue, lateral bud, stem or shoot tip. Most importantly, in most cases, the original plant is not destroyed while collecting the source sample which would hold considerable importance to the owner of the plant in case of rare species.
After placing the sample in tissue culture, the process brings out proliferation of either lateral buds and adventitious shoots or differentiating shoots right from the callus, resulting in a tremendous increase in the number of shoots available for rooting. In the second stage, microcuttings or plantlets that have got rooted by now will be established in the production environment and successfully developed in containers or fields. There are two important lessons learnt from the above said process. 1) This methodology is the most potential means of accelerating asexual propagation of plants. 2) Plants evolved through this technique are found to respond in the same manner like any vegetatively propagated plant that has rooted on its own.
In less than one yearâ€™s time micro-propagation technique can help in multiplying several thousands of plants from a single explant. While the collection of original tissue does not destroy the parent plant, the vigorously dividing cultures become the source of micro-cuttings that can bring about production of plants under green house conditions without any interruptions by changing seasons. The micro-propagation technique also helps in rapidly introducing select number of superior clones of ornamental plants in adequate quantities to sweep the landscape plant market.