variegated leaves

[karrolhk]

I have 3 questions about variegation in orchid leaves:

1. What causes some orchids to have NATURAL (not induced) variegation on their leaves? Is it also because of genetic mutation that some leaves just lack the green pigment chlorophyll in some plant cells?


2. Can the orchid name tell me if an orchid is variegated naturally or induced by virus? e.g. "Dendrobium anosmum variegated" - does the word "variegated" at the end tell me that this species is variegated artificially (induced by virus)? Similarly, orchid names without the word "variegated"/"variegata" means that the orchid is variegated naturally? e.g. Phalaeneopsis schilleriana?


3. Everytime when somebody talks about variegated leaves, the "neofinetia" species is often brought up. Are all vanda neofinetia variegated?


Thank you

[estación seca]

Variegation is anomalous chlorophyll distribution in plants that normally have even distribution. It takes the form of yellow or white stripes in normally all-green plants. It is caused by a partial or complete lack of chloroplasts in some tissues in the leaf. When viral infection causes striping, it is not variegation. It is a result of direct toxic action of the virus.

Some plants have normally spotted or striped leaves, like many Phalaenopsis species. These are not considered variegation because they still have normal distribution of chloroplasts in tissues.

Variegation can be natural. During cell division cytoplasmic organelles like chloroplasts are usually split about evenly between daughter cells. But sometimes by chance one daughter cell will have no chloroplasts. If this happens in the meristem - the dividing tissue at the tip of a growth - it may become permanent.

Neofinetia normally has all-green leaves. The various older Neofinetia variegated selections have this kind of variegation.

It is possible to use certain chemicals to kill chloroplasts. If these are applied to living meristem tissue, and the plant survives, variegation may be induced.

I don't know whether this has been done in Neofinetia, but some newer variegated Neofinetia forms could have been created in this manner.

[karrolhk]

Originally Posted by estación seca

Some plants have normally spotted or striped leaves, like many Phalaenopsis species. These are not considered variegation because they still have normal distribution of chloroplasts in tissues.

Thank you, estación seca. So, for leaves like this in the pic below (from Phalaenopsis Schilleriana) with a UNIFORM variegated pattern, the leaves are grown naturally with alternate places with and without chloroplasts?

Originally Posted by estación seca

It is possible to use certain chemicals to kill chloroplasts. If these are applied to living meristem tissue, and the plant survives, variegation may be induced.

For induced mutation, if chemicals are used to kill chloroplasts, will the chemical only have effect on 1 leaf? will the new leaves of the plant still have induced variegation caused by the chemical?

---------- Post added at 09:19 PM ---------- Previous post was at 08:58 PM ----------

Also, what do you think about this question:

2. Can the orchid name tell me if an orchid is variegated naturally or induced by virus? e.g. "Dendrobium anosmum variegated" - does the word "variegated" at the end tell me that this species is variegated artificially (induced by virus)? Similarly, orchid names without the word "variegated"/"variegata" means that the orchid is variegated naturally? e.g. Phalaeneopsis schilleriana?

[Fishkeeper]

I've never heard of growers intentionally infecting orchids with viruses to make them variegated. There are variegated varieties of almost every common houseplant and many uncommon ones, and those are done without viruses.

I would expect that "[orchid name] variegated" means "this orchid is not normally variegated, but this particular strain is", whereas orchids that are variegated but just called "[orchid name]" are ones where they're all like that.

[estación seca]

Variegation is caused by part of the meristem lacking normal chloroplasts. Variegation is not caused by viruses. Virused striping is caused by infected and damaged cells not developing properly.

Phals with spotted leaves, like the one you show, are not variegated. They have chloroplasts throughout the leaves. The spots are caused by other factors causing light to reflect differently.

Many gesneriads, Pelargoniums and Pileas have striped or spotted leaves that are not variegation. However, among gesneriads, there are a lot of variegated African violets sold (Saintpaulia hybrids.)

A variegated plant may become virus-infected, but that is not the cause of the variegation. Most virus infections are asymptomatic, and cannot be identified unless the plant is tested.

There are almost no normally variegated plants in the wild. They are all mutations of normal plants. Some may occur and persist in populations of normal plants, but this is not a normal state. Variegated plants, because they lack some chloroplasts, cannot produce as much food as normal plants, and are at a competitive disadvantage. They are often more difficult to grow in cultivation than normal plants. In general, the greater the extent of the white, yellow, orange or red striping, the more difficult they are to grow.

When people use chloroplast poisons to induce variegation, they select out resultant plants that look the best, and have stable variegation. This occurs when the affected cells are in the meristematic tissue. It is possible the poisons might affect only one leaf, but this would not be propagated for sale, since it would not persist to produce lots of plants for sale.

Many times variegated plants can only be propagated by dividing rhizomes, or rooting stems. The variegated snake plants, Sansevieria, must be propagated by divisions to maintain the variegation. They root and put up new plants easily from pieces of leaves, but the new growth comes from one tiny part of the leaf being used to grow the cutting. It is never from the part lacking chlorophyll, so this kind of plant always produces normal, non-variegated plants from leaf cuttings.

Some variegated Agaves produce offsets all around the base. The variegation is often somewhat more pronounced from one side of the plant to the other. It is important to choose offsets from the correct part of the plant. I have seen Agaves that were half normal, and half without chlorophyll entirely. In this case the apical (central) meristem at the top of the stem was half normal and half without chloroplasts. Plantlets produced from the white side would not grow when separated from the parent plant because they could not make food. Plantlets from the green portion were normal, unvariegated plants. Plantlets from the border between normal and white were also partially variegated.

Many variegated plants produce normal, non-variegated growth from time to time. Gardeners remove these normal parts so they don't overgrow the more desirable variegated part. I have seen this commonly with certain variegated Pelargoniums, and with some variegated cacti. There is a Pelargonium with very attractive zones of brown pigment on the leaf, and bright red flowers. It occurs in a variegated form, with white zones on the leaves as well. The variegated form is not very robust. It often sends up branches which are normal, and these branches grow very fast. Gardeners need to keep pruning out the normal growths or the white banded form is crowded out.

You can't tell a variegated plant is the result of a chance mutation, or was induced in a lab with chloroplast poisons, unless the person who produced the variegated plant tells you.

[A. thom Aberdares]

In the below photo a Diaphananthe / Rhipidoglossum kind of plant with darker spots than the base color. All leaves have them, and all other plants I have seen of this species have them. Sometimes you can see darker spots in e.g. roses when a crop is growing very vigorously and are also called 'grow spots'. I don't think this is a case like that. Doesn't look like a detrimental virus either. Is this the normal species, variegated, or? NB The plant looks a bit like Rhipidoglossum oxycentron but I am not sure it is the one.

[estación seca]

Hard to say. In a habitat plant the spots might also be algae or fungi growing on the plant surface.