In order to understand why succulents develop mutations, we need to take a look at how plants grow in the first place. All plants grow by increasing the number of cells at the tips of roots and shoots. This is a way plants add length. Regions at the top of the plant with active cell division are called apical meristems and this kind of growth is called primary growth. This is where most of the mutation is likely to happen.
What Happens When The Growth Starts To Mutate?
Some plants, like the monocots, have meristems at the leaf bases that cause leaves to elongate. Woody plants have additional meristems called lateral meristems that produce secondary growth. The most important lateral meristem is the vascular cambium, which produces bark and wood. Crested and monstrose growth only involves primary growth.
Finely tuned and highly regulated cell division in the apical and intercalary meristems can result in some of the distinctive stem and leaf shapes. Rapid apical growth with suppressed branching results in long, slender stems. On the other hand, slow growth will give “fatter” stems. Those highly branched stems are a sign of no apical dominance.
For example, cacti have apical dominance and slow growth, which makes them “fat”. Cells filled with water are what make them succulents. Columnar cacti are caused by faster growth and slower growth results in barrel cacti.
Usually, growth mutation happens when there’s something wrong with a regulated and coordinated cell division in the primary meristems. Causes of mutation can range from virus or bacteria diseases to injuries. Three of the most common growth mutations are crests, monstrose and variegation.
How Do Growth Mutations Look Like?
When the succulent is crested, the growth mutation changes the shape of the apical meristem. Instead of a singe growth tip, you can notice a line, with a fan-like or crested growth in the area of active cell growth. With monstrose mutations, the local apical dominance is gone and every growth tip grows as if it is a dominant point. This results in lumpy, jumbled and knobby growth.
However, crested and monstrose growth is not unique to succulents. You can also find crests in many genera of non-succulent plants, including many common garden plants.
Even if your plant is crested or monstrose, that doesn’t mean you can’t grow it the same as normal plants of the same species. Still, these plants tend to be more sensitive and to request a little extra love. This is one of the reasons why crested and monstrose plants are often grown as grafts. They still flower and produce seeds as any other plant do. However, the grown mutations are generally transmitted by seeds, so the best way to propagate these plants is by cuttings.
Variegation in succulents is almost always initially caused by normal genetic variation. Variegated succulents even get selected and magnified in a cultivation process, due to their mutation. In the wild, most variegates are eliminated because of the tendency of variegated tissues to be weaker and more prone to insects, sunburns, low photosynthesis abilities in low light conditions and fungi and bacterial infections. In cultivation and in the right environment, these plants can perform beautifully and make excellent outdoor and indoor plants.
Variegation is usually caused by the lack of chlorophyll in the leaf section. This can cause the forming of the yellow or white band, streak or mottling of the tissue. Sometimes plants variegate due presence of pigments that mask the chlorophyll pigments and produce darker colors, like purples and reds. There are two types of variegation. One streaking down the middle of leaves is called medio-variegation. One appears on the sides of the leaves is margin-variegation.