3 Aug 2021

Succulent Tissue Culture - The Way to Save the Endangered Species of Succulents

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

What are succulents?

Succulents are plants with thick fleshy tissue. The plant organs are suitable to retain water in arid climates to survive. The water containing the organ can be stem, as in cacti, or leaves, like in agave. These plants are found in more than 60 families of plants including Aizoaceae, Cactaceae, and Crassulaceae.

These plants possess some characteristics to fit in a dry atmosphere or water-scarce condition. They include:

• Thick swollen stems, leaves, or pads and are able to store water over an extended period of time.
• Deep Roots.
• Little or no leave to reduce vaporization of water.
• Presence of spine.
• Hairy or waxy surface of the plant to reduce water loss.
• CAM (Crassulacean acid metabolism) pathway of photosynthesis.

Image: Two different species of Echeveria species (succulents).

Credit: Desert Plant adaptation

Why are they important and popular?

Gone are the days when succulents could only be grown in arid or semiarid conditions. Now, these plants can be found everywhere. You can observe them sitting in your home, office, restaurants, or gardens. Some of the most commonly grown succulents are Burro’s Tail (Sedum morganianum), Flaming Katy (Kalanchoe blossfeldiana), Crown of Thorns (Euphorbia milii), Jade Plant (Crassula ovata), Panda Plant (Kalanchoe tomentosa), Aloe Vera (aloe vera), Zebra Plant (Haworthia fasciata), and Snake Plant (Sansevieria trifasciata).

Their charm has spread among people from all continents because of several reasons some of which are explained below:

• Succulents can be grown anywhere.
• Succulents are convenient to grow.
• Succulents require very little maintenance.
• Succulents are easy to propagate.
• Succulents have beautiful shapes, sizes, colors, and textures, required for home/office decor.

How are succulents grown?

Succulents are one of the plants that are easiest to propagate. They are cost-effective and simple plants to grow for your garden or home decor. You can grow these plants using any of their parts including the offsets, leaf cuttings, stem cuttings, or seeds from a mature plant.

The sky-rocket demands of succulents around the world have created chaos among the succulents industries. The most efficient technique proposed for this problem is tissue culture. It's a tool that is popular among plant industries because of its several use cases:

• To rapidly-produce plants in mass.
• To protect endangered plant species.
• To produce hybrid plants.
• To produce disease-free plants.
• To produce a true line of plants.

How can tissue culture be a savior for endangered succulents species?

The heavy demands of these plants are impacting the diversity and presence of many of the succulents. Not only this, but the anthropogenic activities in their cultivation areas are shrinking their growth land. This disbalancing situation is leading to the extinction of some succulents and bringing some others to the red list of IUCN, which displays the endangered species.

Some of the endangered succulents are Mammillaria herrerae, Agave pax, Aloe pillansii, Estevesia alex-bragae, Parodia rechensis, Monanthes wildpretii, Discocactus subterraneo-proliferans, and Rhipsalis triangularis.

These are just a handful of names, but according to the IUCN, “their assessment revealed cacti to be one of the most threatened taxonomic groups assessed to date: almost a third (31%) of the 1,478 species evaluated are classified as threatened.”

Tissue Culture of succulents to protect endangered species

The succulents on the verge of extinction are difficult and risky to propagate using conventional techniques. The extreme declining rate of these succulents necessitates the implementation of effective conservation measures to ensure their survival and sustainable use.

The conventional methods require the availability of sufficient propagules/seedlings for large-scale cultivation and to meet the sustainable growing demand of succulents. This is one other challenge in growing these plants using conventional techniques.

In tissue culture, only a single cell, tissue, or any available part of the succulent can be used to produce hundreds of plants.

Micropropagation of succulents involves the following four steps:

1. Establishment of culture (Initiation stage)

• In this stage, the mother or donor plant is chosen to collect the explants (a piece of tissue or part of the plant) for the process of propagation.
• The explant containing part of the plant is cut off from the mother plant.
• The explants are prepared by cutting and trimming them into the desired size, as required for the culturing process.
• The explants are surface sterilized (cleaning and treating the tissues with chemicals to kill microbes present on their surface) using 5% sodium hypochlorite, 0.1% mercuric chloride, or 70% alcohol (or any other chemicals like these).
• After surface sterilization, explants are placed in the media containing culture vessels to differentiate into a callus.

2. Multiplication of explants (multiplication stage)

• In this stage, the callus obtained from the previous stage is further divided into smaller tissue pieces using a sharp knife and without any damage.
• Then, the tissues are placed in the media containing culture vessels and kept in a suitable environment for tissue differentiation.
• The culture media at this stage is often supplemented with plant growth hormones (generally cytokinin-rich media is used) for the development of shoots.

3. Rooting stage

• The shootlets developed in the previous stage are then taken and treated with certain chemicals and hormones for root development.
• The obtained shoots are divided into individual shoots and then transferred onto culture media supplemented with a rooting hormone (auxin-rich culture media).

4. Acclimatization stage

• After the plantlets are developed with desired shoot length and roots, then, they are ready for their acclimatization.
• Acclimatization is a process of gradually adapting the plant to the natural environment from the artificial lab environment. It’s essential to avoid stress, moisture, and several diseases.
• Sometimes, a mixture of peat moss, pearlite, or vermiculite is used for hardening plants before transferring them to soil containing pot.

The whole procedure of micropropagation requires maintaining aseptic or sterilized conditions. To propagate endangered plants requires some expert hands to handle those plants carefully and perform in vitro propagation without any severe damage to the plant or tissue loss.

So if you are a tissue culture enthusiast, then visit our store for all your tissue culture requirements including MS media, agar, gelatin, PPM, and culture vessels. You can also make use of our consulting services if you need any help in your tissue culture processes.

Happy Culturing!!