18 May 2022

What Is Embryo Rescue?

Anjali Singh, MS

As a content and community manager, I leverage my expertise in plant biotechnology, passion for tissue culture, and writing skills to create compelling articles, simplifying intricate scientific concepts, and address your inquiries. As a dedicated science communicator, I strive to spark curiosity and foster a love for science in my audience.

Table of Contents

Overview

Embryo rescue is a technique used to protect the weak, immature, and hybrid embryo and promote it to develop into a complete plant. It’s one of the earliest successful in vitro/tissue culture techniques.

It was documented by Charles Bonnet in the 18th century when he successfully excised the embryos of Phaseolus and Fagopyrum and successfully planted them into the soil. Later, many scientists started testing the process with several nutrient media. Between 890-1904, embryo rescue was tested using nutrient media containing salt and sugars and tissue culture techniques.

In 1904, Hanning for the first time successfully introduced embryos in tissue culture. However, he faced the problem with precocious or early embryos, which resulted in the development of small and weak plantlets.

Embryo rescue is one of the essential techniques for plant breeding. It allows the growth of weak embryos, specially developed through interspecific or intergeneric crosses, to develop into complete plants.

In nature, often the embryos that develop through interspecific or intergeneric crosses are underdeveloped and couldn’t develop into a plant and in many cases where the crosses are made between incompatible plants, the embryos are aborted. The tissue culture techniques, such as embryo culture, are saviors for these plants and develop various hybrid plants.

This article teaches you about embryo culture techniques and the application and considerable factors for embryo rescue.

What Do You Know About Embryo Culture?

Embryo culture is one of the extensively and commonly used techniques for embryo rescue. In this method, seeds are collected from controlled pollination plants before an embryo is expected to abort. After this, the embryo is isolated and excised in a sterile condition, followed by directly culturing it on the culture medium to obtain viable plants.

Based on the type of embryo introduced into the culture medium, the embryo culture is of two types:

Mature Embryo Culture: It’s the process of culturing mature and ripped embryos in suitable laboratory conditions. It’s done when the embryos don’t survive in natural in vivo conditions, become dormant for a long time, or when seed germination is inhibited.
Immature Embryo Culture: It’s used to culture immature, weak, or small embryos that fail to develop into hybrid plants due to endosperm degeneration in natural conditions. This is also known as embryo rescue, as by culturing the embryos they are being rescued and promoted to develop into a complete plant.

Factors that Influence the Embryo Culture

Composition of the medium: Generally, two types of media are used for the embryo culture, Murashige and Skoog media (or MS media) or Gamborg’s B-5[ media. However, often the supplements of the media are required to vary. For example, young embryos require high sucrose concentration whereas mature embryos require low sucrose.
Time of Culture or embryo stage during culture: Embryos are suggested to be cultured before embryo abortion. However, due to difficulty in rearing and obtaining embryos at a very early stage, they are allowed to grow in natural or in vivo conditions as much as they can develop and grow.
Temperature: The temperature for embryos of different plants depends on the species of the plants. For example, plants from the cold season require lower temperature, however, plants from warmer seasons prefer higher temperature.

Applications of Embryo Culture

Embryo culture is used for several breeding purposes, some of which are explained below:

To achieve a cross between diploids and tetraploids.
Determine the seed viability.
Interspecific and intergeneric breeding of incompatible species.
Shorten the breeding cycle of deciduous trees.
To study the physiology of seed germination and development.
For in vitro colonel propagation of plants, especially conifers and members of Gramineae family.
To study nutrient requirements and morphogenesis.
To germinate seeds of obligatory parasites without the host.

Other Techniques of Embryo Rescue

In addition to embryo culture, the techniques that can be used for embryo rescue, especially for small-seeded plant species or plants with young embryos, are ovary and ovule culture.

Ovary Culture: In this method, flowers of either pollinated or non-pollinated plants are excised, and the ovary from the flower’s pistil is removed and cultured either on the nutrient medium for the regeneration of complete plants. The technique is also known as gynogenesis.
Ovule Culture: In this method, the ovule is isolated from the ovary in an aseptic condition and cultured on a chemically defined nutrient medium under controlled conditions. The technique helps in understanding the factors that regulate a zygote's development into a mature embryo.

How Plant Cell Technology Is Helping Culturists Worldwide In Their Tissue Culture Application?

Plant Cell Technology is helping tissue culturists around the world by providing unique and world-class products and services that smoothen their process. It has MS media, agar, gellan gum, Plant Preservative Mixture (PPM), culture vessels, Biocoupler (TM), and masks in its store to facilitate your processes.

And, that’s not it! Plant Cell Technology also offers consultation services to culturists of all sizes that help to get instant solutions to your tissue culture problems.

So, visit plantcelltechnology.com today and find out more about our product and services and how they help you to excel in your tissue culture processes.

Happy Culturing!!

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