Variegation in plants is described as the appearance of differently colored zones in the plant's organs such as leaves or flowers, and it is mostly manifested as stripes, blotches, steaks or splashes. The word "Splash" has been widely used to describe pigmentation patternings or variegations in plumerias by a number of plumeria glowers. Splash such as natural splash is a form of natural colorations which is genetically regulated but its phenotype can be affected by a number of factors, and is often mistaken for other kinds of splashes or vice versa. Differentiating between virus induced symptom (viral splash), natural coloration (natural splash) and variegated mosaics due to shoot apical meristem layer-specific mutations (chimeral splash) in plumeria can be challenging. This requires experience, and many times it needs to be investigated scientifically in laboratory. Below is a brief overview on basic characteristics of these splashes and a few similar variegations which are found in plumerias, and how they arise.
Figure 2. Natural splash in Miracle plumeria governed by unstable color expression gene - Left: Intense reddish natural splash located on one side of each petal, Middle: Less pronounced red splash on one side of each petal, Right: The natural splashes that appear on petals are always at the same location in all flowers and have consistent pattern from flower to flower (repeated pattern).
Figure 3. Natural splash in Madame Poni plumeria governed by unstable color expression gene - Upper left: Intense reddish splash only within incurved area, Upper middle: Less pronounced red splash to almost no splash in incurved area, Upper right: Less pronounced splash in non-incurved flower, Lower left (Flowers with incurved petals) and Lower right (Flowers with non-incurved petals): As shown in these pictures, the natural splashes (if any) that appear on each petal are always at the same location and their pattern is consistent from flower to flower (repeated pattern).
Figure 4. Natural splash in Purple Serendipity plumeria governed by unstable color expression gene - Left: Nonatural splash, Middle: With natural splash in summer season (green arrow), Right: The natural splashes (if any) that appear on petals are always at the same location in all flowers and have consistent pattern from flower to flower (repeated pattern).
Figure 5. Natural splashes in various plumeria cultivars governed by unstable color expression gene - Left:Natural splash (located at the tips of each petal) in Tempest plumeria, Middle: Natural splash (a narrow stripe running almost the length of each petal) in Buddha Raksa plumeria, Right: Natural splash (located within incurved area of each petal) in Sangria Stripe plumeria. As the natural colorations are governed by unstable expression gene, a number of factors may have an impact on their phenotypes of these splashes under various conditions. As shown in these picture, the natural splashes that appear on petals are always at the same location and their pattern is consistent from flower to flower (repeated pattern).
Figure 6. Paint brush/striated strokes or brushstroke-like effect on flower petals especially near the petal edges: It is a type of natural coloration found in some plumeria cultivars, and their genetic traits can pass down from one generation to the next. Left: Penang Peach, Middle: Tropical Aurora - a seedling of Penang Peach, Right: Unnamed plumeria - a seedling of Tropical Aurora. Similar trait is also found in some other plumerias such as Doric, Chocco Delight and Goldilocks.
Somewhere early in the development of a flower and leaf, any genetic mutation in cell(s) in a shoot apical meristem (which gives rise to plant body) can result in the generation of chimera. The location and pattern of chimeral splash on a petal and leaf directly relate to where in the meristem, the mutated cells are located; and how these cells duplicate themselves (cell division) during plant's growth. Due to the differing planes, durations and rates of cell division amongst mutated and non-mutated cells while the flower and leaf being formed, chimeral splash is irregular in coloration pattern and shape, and appears at unpredictable locations on plant's parts. The most common feature of chimeral splashes on flowers is the narrow white colored stripes running along the petal length (Fig. 8, 9 and 10).
In case of a flower, splash in cultivars such as Fantasia and Marble Ice Cream plumerias fall into this category i.e. white (colorless) stripes on the petals are due to the presence of mutated cells in white/colorless area whereas a sort of washed-out pink/red colored stripes are due to the arrangement of both mutated and non-mutated cells in such areas (Fig. 8).
Figure 13. Chimera in plumerias - Left and Right: Possibly non-patterned sectorial chimera with random colorless patches or stripes
Figure 14. Creating stable periclinal chimeras - Left image: Plumeria stems with sectorial chimera that is highly unstable. Mutated cells extend vertically through all cell layers within the bud or meristem. The border between each genotype, i.e. nonmutated cells (normal green) and mutated cells (no chlorophyll pigment), is almost parallel within the stem giving sectorial chimeras a candy cane like appearance. By removing and grafting an axillary bud that develops in the axil of a variegated leaf (as seen in the Middle image) to a rootstock, one may get a periclinal climeral plumeria with unique foliar pattern of variegation (plant on the left of the Right image) which is relatively stable and can be vegetatively propagated.
Viral Splash
Viral Splash (or so-called color break symptom) may be found in any plants which are infected with Frangipani Mosaic Virus (FrMV). FrMV replication and activity in plant causes a change in color pattern of pigmented flower and leaf by over-accumulation of epidermal anthocyanin pigments. In this case, anthocyanin may play role in plant defense mechanism against pathogen (i.e. FrMV) which is active in that particular area.
In general, viral splashes in most plumeria flowers can be distinguished from other kinds of splashes (1) by their intense discolored areas (due to the accumulation of anthocyanin in the area of high viral activity) on the flower petals i.e. dark red/maroon splash on red flower, darker pink on pink and light pink flower, red on yellow flower, and dark purple on purple flower, (2) by their uneven/unpredictable forms and sizes (vary widely in shape and size), (3) by their unpredictable locations, and (4) by its non-consistent patterns (non-repeated patterns) from petal to petal and flower to flower (Fig. 15 and 16). On foliate, the virus also unevenly causes the deficiencies in chlorophyll pigments resulting in mosaic appearance (non-uniform chlorosis). The viral symptoms on leaf may also include stains, discoloration and mottled appearance due to anthocyanin accumulation (Fig. 17 and 18). One important feature of the viral mottled markings on leaves is that their appearance (color and pattern) keeps changing as the leaves expand and as the symptom progresses into other stages. The color of viral symptoms generally fades when the leaves age. The severity of FrMV infection and its symptom on flowers or leaves can vary greatly depending on the strain of FrMV, the cultivar/specie of the plumeria (host plant) as well as the environmental conditions such as temperature.
If Miracle plumeria (having natural splash) and Fantasia or Maya (having chimeral splash) plumerias are infected with FrMV, the viral splash (symptom) may also appear on these plants and this can complicate the interpretation of the splashes (Fig. 19-23). Splash which is located beyond the boundary of natural splash is likely due to FrMV or other means such as insects, fungus, chemicals and etc. The anthocyanescent splashes or markings associated with the infections of insects and etc. are unique and differ from the splash caused by the FrMV.
As FrMV is easily transmitted by physical contact (via sap), it can spread rapidly and covertly in plumerias with poor cultural and sanitation practices (such as using unsterilized and/or contaminated cutting tools between plants or grafts). It may lie latent for many months or longer before expressing its symptom. A few flowers (or petals) and leaves (also other parts such as petioles and stems) may show symptoms and then apparently healthy flowers and leaves are produced, or they may alternate between asymptomatic or symptomatic on the same plant. Viral infections of plants are incurable. Any plant that is vegetatively propagated from a virus-infected mother plant will also be infected. This virus now has a worldwide distribution via infected cuttings, grafts and plants which have caused once rare disease in nature to become a more common disease in cultivation.
High temperature can put a lot of stress on the plumerias as well as provides an ideal condition for FrMV to be more active, and favours FrMV's replication within a plant. FrMV is the most active at 30-35C or 86-95F. It is important to note that heat does not cause this splash to occur (only provide a favorable condition) but the virus present in the plant does. For more information on FrMV, Click FrMV in plumeria
Figure 17. Various viral symptoms on leaves - Left: An early stage of viral symptom (mottling) on newly emerging leaves (which has yet to fully unroll - indicated by the arrow) of Vera Cruz Rose plumeria. The lesion develops further into different forms as the viral activity progresses during leaf enlargement and maturation., Middle: Severe leaf malformation and mottled leaves of Leuang Sa-ngeam plumeria. Notice an early stage of viral lesions (indicated by the arrow)on a newly emerging leaf which normally go unnoticed, Right: Mosaic and faint chlorotic lesions on leaf of Kled Tabtim plumeria
Figure 18. Various viral symptoms on leaves - Left: Stain and discoloration on leaf of virused Dwarf Singapore Pink plumeria, Middle: Stains and discoloration on leaf of virused Puddha Raksa plumeria, Right: Reddish patches/spots on petioles of virused Coral Cream plumeria
Viral splash and Natural splash on the same flower
Figure 19. Natural splash vs viral splash on the same flowers of Miracle plumeria - Left: Miracle with only natural splash, Middle and Right: Viral and Natural splashes on the same flowers of Miracle plumeria at the same time. Viral splash is distinguished by its dark red/maroon in color -- indicated by the arrows. Natural splash (the lighter red bands) appears on one side of petals in all flowers and has consistent pattern from flower to flower (repeated pattern). Whereas viral splash displays a random color splashing with uncharacterized forms and sizes and at unpredictable location, and its pattern is non-consistent from petal to petal and flower to flower (non-repeated pattern).
Figure 20. Natural splash vs viral splash on Madame Poni plumeria - Left: Madame poni with natural splash (an arrow stripe (repeated pattern) running almost the length of each petal). Middle: Viral splash (black arrows) and natural splash (green arrows) on the same flower, Right: In this case, natural splash (if any) is likely musked by viral splash which is characterized by its highly unpredictable forms and sizes and at unpredictable location, and its pattern is non-consistent from petal to petal (non-repeated pattern).
Figure 21. Natural Splash vs Viral Splash on Gam Maam plumeria - Left: Natural splash (located at the center of the flower and is consistent from petal to petal), Middle: Natural splash (only at the center which is its traditional location) with viral splash (at unpredictable locations on the petals), and Right: Viral splashes on yellow colored petals (in this case there is no natural splash on Gam Maam flower as the unstable expression color gene turns off).
Viral splash and Chimeral splash on the same flowers or leaves
Figure 24. Natural splash in Fireblast (left), Chimeral splash in Fantasia (middle), and Viral splash in Rim Fire plumeria (right)
Figure 25. Natural splash (left), Chimeral splash (middle), and Viral splash (right)
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| Fantasia plumeria - a chimera plant |
Natural Splash
Natural colorations occur in a plant that consist of cells having identical genotype but only the genes in specific plant's parts (e.g. leaf, flower, stem, root or the specific cell layers and etc.) are instructed to express or not to express the colors (or to make or destroy the color pigments). Due to the differential gene expression, plant with the homogeneous genotype can have different color for each organ (e.g. leaf can be green while flower can be red, yellow or white and etc.). At the petal level, the petal can have different color in a different location. This kind of differential gene expression is the most common cause of floral coloration patterns in plants including plumeria.
Of all the natural colorations found in plumeria flowers, a highly unstable form of natural colorations is also present on specific regions of petals in some plumeria cultivars. The term "Natural Splash" is applied here to describe an unstable phenotype of flower coloration which is characterised by unstable expression of a gene located at specific location of flower petals. The gene expression which is highly unstable can be influenced by a number of factors such as location (position) on plant's parts (e.g. specific area on petal) and stages of plant development (e.g. flower's age and incurvation of petals) and etc. Whereas plant's regulatory gene determines the coloration of natural splash in flowers, one (or more) of a variety of factors such as the environmental conditions (e.g. plant stress, temperature, light intensity) and cultivation practices (e.g. plant nutrition) affect the plant development and many aspects of plant physiology, which in turn has an impact on gene expression in some extend (i.e. more or less pronounced splash or in some cases with no splash at all).
Plant molecular geneticists relate this phenomenon under certain condition(s) to the switching (partly or totally) "on and off" of color gene in that particular location of the plant's parts (e.g. specific area of petals). The other words, the switches govern gene expression by controlling where, when, and even to what degree a particular gene is turned on. Since natural splash is genetically regulated and geographically predetermined, it has a predictable coloration pattern and occurs at about the same location on each petal. In addition, its coloration and splash pattern at a given condition are consistent (repeated pattern) on every flower (note: not appearing randomly like a virused plant).
Splash in cultivars such as Miracle, Madame Poni, Madame Rainbow, Buddha Raksa, Gam Maam and Kasetsin plumerias fall into this category i.e. red stripe/splash over a part of off-white or yellow area of petals. This is the only area on petals where the genes are instructed to have the natural red splash (relevant mainly to anthocyanin biosynthesis) (Fig. 1-5). As mentioned this natural splash is highly unstable and its look may vary based upon a number of conditions such as the stages of plant development (e.g. incurved petal), environmental factors and etc. Therefore, the splash on the petals may be lighter or darker in color, or more or less area of splash on the petals, or no splash at all. In this case, natural splashes on these flowers express as a part of floral coloration patterns. A good example of natural splash in other plant is the stripes on watermelon rind.
Of all the natural colorations found in plumeria flowers, a highly unstable form of natural colorations is also present on specific regions of petals in some plumeria cultivars. The term "Natural Splash" is applied here to describe an unstable phenotype of flower coloration which is characterised by unstable expression of a gene located at specific location of flower petals. The gene expression which is highly unstable can be influenced by a number of factors such as location (position) on plant's parts (e.g. specific area on petal) and stages of plant development (e.g. flower's age and incurvation of petals) and etc. Whereas plant's regulatory gene determines the coloration of natural splash in flowers, one (or more) of a variety of factors such as the environmental conditions (e.g. plant stress, temperature, light intensity) and cultivation practices (e.g. plant nutrition) affect the plant development and many aspects of plant physiology, which in turn has an impact on gene expression in some extend (i.e. more or less pronounced splash or in some cases with no splash at all).
Plant molecular geneticists relate this phenomenon under certain condition(s) to the switching (partly or totally) "on and off" of color gene in that particular location of the plant's parts (e.g. specific area of petals). The other words, the switches govern gene expression by controlling where, when, and even to what degree a particular gene is turned on. Since natural splash is genetically regulated and geographically predetermined, it has a predictable coloration pattern and occurs at about the same location on each petal. In addition, its coloration and splash pattern at a given condition are consistent (repeated pattern) on every flower (note: not appearing randomly like a virused plant).
Splash in cultivars such as Miracle, Madame Poni, Madame Rainbow, Buddha Raksa, Gam Maam and Kasetsin plumerias fall into this category i.e. red stripe/splash over a part of off-white or yellow area of petals. This is the only area on petals where the genes are instructed to have the natural red splash (relevant mainly to anthocyanin biosynthesis) (Fig. 1-5). As mentioned this natural splash is highly unstable and its look may vary based upon a number of conditions such as the stages of plant development (e.g. incurved petal), environmental factors and etc. Therefore, the splash on the petals may be lighter or darker in color, or more or less area of splash on the petals, or no splash at all. In this case, natural splashes on these flowers express as a part of floral coloration patterns. A good example of natural splash in other plant is the stripes on watermelon rind.
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Figure 1. Natural splashes in Morning Star plumeria cultivars governed by unstable color expression gene - Left: No natural splash, Middle: A tiny natural splash, Right: Flowers with no natural splash and with large natural splashes. As the natural colorations are governed by unstable expression gene, the gene plays an important role on the presence and the sizes of the splashes in such specific areas. In addition, a number of environmental factors may have an impact on the gene expression in some extend. As shown in these picture, the natural splashes (if any) appearing on petals are always at the same location.
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Chimeral Splash
Unlike natural splash, chimeral Splash (or so-called variegation) occurs in plants with two or more genetically distinct types of cells (i.e. mutated and non-mutated cells) that coexist in a plant but express differently. It can involve gains or losses of color pigment(s) in the mutated cells. In case of plumeria, mutated cells are generally associated with the absence of pigmentation in flower and leaf. This is mainly due to the inhibition of anthocyanin or chlorophyll biosynthesis.Somewhere early in the development of a flower and leaf, any genetic mutation in cell(s) in a shoot apical meristem (which gives rise to plant body) can result in the generation of chimera. The location and pattern of chimeral splash on a petal and leaf directly relate to where in the meristem, the mutated cells are located; and how these cells duplicate themselves (cell division) during plant's growth. Due to the differing planes, durations and rates of cell division amongst mutated and non-mutated cells while the flower and leaf being formed, chimeral splash is irregular in coloration pattern and shape, and appears at unpredictable locations on plant's parts. The most common feature of chimeral splashes on flowers is the narrow white colored stripes running along the petal length (Fig. 8, 9 and 10).
In case of a flower, splash in cultivars such as Fantasia and Marble Ice Cream plumerias fall into this category i.e. white (colorless) stripes on the petals are due to the presence of mutated cells in white/colorless area whereas a sort of washed-out pink/red colored stripes are due to the arrangement of both mutated and non-mutated cells in such areas (Fig. 8).
In case of foliage, Maya and Marble plumerias are examples that fall into this category (i.e. variegation seen on leaves is due to the alignment of mutated and non-mutated cells in meristematic layers that give rise to the leaf tissue) (Fig. 12). As these kinds of variegation are the results of somatic mutations occurring in body cells, they are not passed on to offsprings (cannot be seed propagated). These chimera plumerias are rare in occurrence.
The variegated-leaved plumerias from Thailand that are available in the market are chimeral plants. The periclinal chimera (which is relatively stable and can be vegetatively propagated as the whole plant is entirely chimeric) is discovered by removing an axillary bud (having mutated cells at the growing point) from a branch (with mericlinal or sectorial chimeras) and grafting it to a root stock (using bud grafting technique). After sorting and repeating the process over and over for a period of time, Thai growers successfully created periclinal chimeral plumerias with unique foliar patterns of variegation (Fig. 14).
Figures 7 to 14 illustrate the various phenotypes (observable characteristics) of chimeral splashes found in flowers or leaves of plumerias. It is important to note that some phenotypes may go unnoticed as chimera cells can be located in deeper layers and masked by overlaying tissues. With the diversity and complexity in nature of chimeras, it can be misinterpreted if it is done without scientific investigation in the laboratory. Since there are very limited information related to chimera in plumeria, more studies especially at the molecular level should be conducted to provide a more accurate classification of these chimeras.
Figure 9. Rare green chimeral stripes on yellow petal background in Shirakawa Yutaka's plumeria seedlings: In this case, the mutated cells in the green area are either associated with the increase in chlorophyll biosynthesis or the absence of other pigments in the mutated cells allowing the chlorophyll pigments to predominate. The differences in the rate and duration of cell division between chimera cells (green region) and normal cells (yellow region) during petal development resulted in the irregular petal edges on these flowers' petals.
The variegated-leaved plumerias from Thailand that are available in the market are chimeral plants. The periclinal chimera (which is relatively stable and can be vegetatively propagated as the whole plant is entirely chimeric) is discovered by removing an axillary bud (having mutated cells at the growing point) from a branch (with mericlinal or sectorial chimeras) and grafting it to a root stock (using bud grafting technique). After sorting and repeating the process over and over for a period of time, Thai growers successfully created periclinal chimeral plumerias with unique foliar patterns of variegation (Fig. 14).
Figures 7 to 14 illustrate the various phenotypes (observable characteristics) of chimeral splashes found in flowers or leaves of plumerias. It is important to note that some phenotypes may go unnoticed as chimera cells can be located in deeper layers and masked by overlaying tissues. With the diversity and complexity in nature of chimeras, it can be misinterpreted if it is done without scientific investigation in the laboratory. Since there are very limited information related to chimera in plumeria, more studies especially at the molecular level should be conducted to provide a more accurate classification of these chimeras.
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Figure 7. Sectorial floral chimera splashes in plumerias - Left: One petal of flower (white petal) made up one different cell type (i.e. mutated cells which stopped producing the usual pink/red pigment). Middle and Right: Sometimes both genotypes (colors) are expressed together in individual petals giving them a beautiful split coloration pattern. This type of chimera is very unstable and can not be vegetatively propagated.
Figure 8. Floral chimera splashes in plumerias - Left (Fantasia plumeria) and Middle (Marble Ice Cream plumeria): These are possibly non-patterned sectorial chimera that mutated cells are scattered randomly throughout the layers of both apical and inflorescence meristems that give rise to petals. White colored stripes on their petals are the area that the mutated cells are present whereas the area with mixed colors (white and light pink/red) are due to the arrangement of mutated and non-mutated cells. Although these chimeral stripes are non-repeated patterns, the plumerias with this kind of chimera can be vegetatively propagated (i.e. from stem cuttings). Right: Fringed petals with white chimeral stripes in Hana Emi plumeria. The irregular (e.g. shallow-lobed or serrated or tooth-like) edges of petals at which the white stripes are present are the result of the differences in cell division rate and duration between chimera cells (white region) and normal cells (pink region) during petal development. Similar irregular petal edges are also found in Fantasia and Marble Ice Cream plumerias.
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| Figure 10. Rare, complex types of floral splashes (variegations): Left and middle: Twin stripe (white and red regions on a pink petal) in Charlotte Ebert (left) and an unknown (middle) likely descended from a somatic cell that underwent somatic crossing over (interchange of chromosomal parts resulting in the change of color expression of this floral mutated gene) during cell division. The mutated cells in white area are associated with the absence of pigment while those in red area are associated with the increase in anthocyanin biosynthesis. The normal pink area which constitutes non-cross-over tissue (normal tissue) remains pink in color. Right: Mixed types of floral variegations i.e. sectorial chimera (solid white region on a petal) and other unknown types of variegation (possibly caused by either somatic crossing over or transposons (jumping genes - a DNA sequence that can change its position within a genome) resulting in the change of color expression of floral color genes). |
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Figure 11. Mericlinal chimera in plumerias - only some parts of plant are chimeric: Left, Middle and Right: Variegated and normal (green) branches in the same plant. This type of chimera tend to be unstable and in time one genotype will out compete the other causing the tree to revert either completely green (normal plant) or other types of chimera plant.
Figure 12. Periclinal chimera in plumerias - exhibiting uniform and stable variegation which can be vegetatively propagated (e.g. from cutting) as the whole plant is entirely chimeric. Left: Marble plumeria, Middle: An unknown variegated plumeria, Right: Maya plumeria
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Viral Splash
Viral Splash (or so-called color break symptom) may be found in any plants which are infected with Frangipani Mosaic Virus (FrMV). FrMV replication and activity in plant causes a change in color pattern of pigmented flower and leaf by over-accumulation of epidermal anthocyanin pigments. In this case, anthocyanin may play role in plant defense mechanism against pathogen (i.e. FrMV) which is active in that particular area.
In general, viral splashes in most plumeria flowers can be distinguished from other kinds of splashes (1) by their intense discolored areas (due to the accumulation of anthocyanin in the area of high viral activity) on the flower petals i.e. dark red/maroon splash on red flower, darker pink on pink and light pink flower, red on yellow flower, and dark purple on purple flower, (2) by their uneven/unpredictable forms and sizes (vary widely in shape and size), (3) by their unpredictable locations, and (4) by its non-consistent patterns (non-repeated patterns) from petal to petal and flower to flower (Fig. 15 and 16). On foliate, the virus also unevenly causes the deficiencies in chlorophyll pigments resulting in mosaic appearance (non-uniform chlorosis). The viral symptoms on leaf may also include stains, discoloration and mottled appearance due to anthocyanin accumulation (Fig. 17 and 18). One important feature of the viral mottled markings on leaves is that their appearance (color and pattern) keeps changing as the leaves expand and as the symptom progresses into other stages. The color of viral symptoms generally fades when the leaves age. The severity of FrMV infection and its symptom on flowers or leaves can vary greatly depending on the strain of FrMV, the cultivar/specie of the plumeria (host plant) as well as the environmental conditions such as temperature.
If Miracle plumeria (having natural splash) and Fantasia or Maya (having chimeral splash) plumerias are infected with FrMV, the viral splash (symptom) may also appear on these plants and this can complicate the interpretation of the splashes (Fig. 19-23). Splash which is located beyond the boundary of natural splash is likely due to FrMV or other means such as insects, fungus, chemicals and etc. The anthocyanescent splashes or markings associated with the infections of insects and etc. are unique and differ from the splash caused by the FrMV.
As FrMV is easily transmitted by physical contact (via sap), it can spread rapidly and covertly in plumerias with poor cultural and sanitation practices (such as using unsterilized and/or contaminated cutting tools between plants or grafts). It may lie latent for many months or longer before expressing its symptom. A few flowers (or petals) and leaves (also other parts such as petioles and stems) may show symptoms and then apparently healthy flowers and leaves are produced, or they may alternate between asymptomatic or symptomatic on the same plant. Viral infections of plants are incurable. Any plant that is vegetatively propagated from a virus-infected mother plant will also be infected. This virus now has a worldwide distribution via infected cuttings, grafts and plants which have caused once rare disease in nature to become a more common disease in cultivation.
High temperature can put a lot of stress on the plumerias as well as provides an ideal condition for FrMV to be more active, and favours FrMV's replication within a plant. FrMV is the most active at 30-35C or 86-95F. It is important to note that heat does not cause this splash to occur (only provide a favorable condition) but the virus present in the plant does. For more information on FrMV, Click FrMV in plumeria
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Figure 15. Viral symptoms on flowers of various plumerias - Left: Red splash on a flower of virused Veracruz Rose plumeria, Middle: Maroon splash on flowers of virused J-105 plumeria, Right: Red splash on flower of virused Vishanu Gold plumeria
Figure 16. Viral symptoms on flowers of various plumerias - Left: Dark purple splash on flowers of virused Muang P-26 plumeria, Middle: Red splash on flowers of virused Dwarf Singapore Pink plumeria, Right: Red splash on a flower of virused Bali Whirl plumeria
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Viral splash and Natural splash on the same flower
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Figure 22. Viral splash on Chimeral splashed flowers: Under construction
Figure 23. Viral symptoms on variegated (chimeral) leaves - Left: An early stage of viral symptom on leaf of variegated Marble Gold plumeria, Middle: Stains and discoloration (light brownish red splotchy markings over the entire leaf area) on leaf of variegated Namwan plumeria, and Right: Viral symptom (brownish stains and discoloration) on leaf blade, veins, mid rib and petiole of both young and mature leaves of variegated Maya plumeria.
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Comparison of some key characteristics of Natural, Chimeral and Viral Splashes
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1. Genotype
Natural Splash: Homogeneous type of cells (all are normal cells)
Natural Splash: Homogeneous type of cells (all are normal cells)
Chimeral Splash: Two or more genetically distinct types of cells (normal and mutated cells)
Viral Splash: Any plumeria plants (both normal and chimera plants) can be infested with FrMV (Note: virus is able to infect plants regardless of genotypes)
2. A Form of Anomaly?
Natural Splash: No (It is a highly unstable form of natural coloration controlled by unstable expression gene)
Natural Splash: No (It is a highly unstable form of natural coloration controlled by unstable expression gene)
Chimeral Splash: Yes (related to mutation)
Viral Splash: No (It is simply a symptom of viral infection.)
3. Location of Splash
Natural Splash: Always at the same location
Natural Splash: Always at the same location
(splash (if any) is always at the same location as it is genetically regulated and geographically predetermined)
Chimeral Splash: Unpredictable location
(splash/stripe is only at the area where the mutated cells located)
Viral Splash: Random
(appears randomly on plant's parts which are the areas where the virus is active)
4. Pattern of Splash
Natural Splash: Repeated pattern (consistent from petal to petal and flower to flower)
Natural Splash: Repeated pattern (consistent from petal to petal and flower to flower)
(The pattern seen is the result of differential gene expression between genetically identical cells.)
Chimeral Splash: Unpredictable pattern
(The pattern seen is the result of the arrangement of two or more genetically distinct types of cells. It also depends on the direction of the growth of mutated cells, and the difference in rate and duration of cell division between mutated and normal cells.)
In flowers (for an example), it is in the form of stripes running along the petal length (Fig. 8-10).
Viral Splash: Non-repeated pattern (non-consistent pattern)
(The patterns of viral symptom vary within the same plumeria cultivar and from cultivar to cultivar. Moreover, they are not consistent from petal to petal and flower to flower.)5. Coloration of Splash
Natural Splash: Red splash (on flower) (due to anthocyanin biosynthesis)
Natural Splash: Red splash (on flower) (due to anthocyanin biosynthesis)
Chimeral Splash: Colorless (in most cases) (due to the absence of pigments in mutated cells)
Flowers and Leaves: The overall variegation may fade with age but the chimera pattern remains the same.Viral Splash: Intense discolored areas on flowers (due to anthocyanin accumulation.)
Symptom on flowers: Dark red/maroon splash on red flower, darker pink on pink and light pink flower, red on yellow flower, and dark purple on purple flower
Symptom on leaves: Stains, discoloration and mottled appearance on leaves (due to anthocyanin accumulation or chlorophyll deficiency.) *The viral markings on leaves keep changing in appearance (color and pattern) as the leaves expand and as the symptom progresses into other stages.
**The symptoms do NOT necessarily appear on flower and leaf at the same time.
6. Splash present on Plant
Natural Splash: Come and go, and reappear (but always reappear at the same location on petals)
(As it is govern by the unstable expression gene and affected by the environmental conditions)Natural Splash: Come and go, and reappear (but always reappear at the same location on petals)
Chimeral Splash: Come and go, and may or may not reappear (depend on the location of mutated cells within plant's tissues)
(Chimera splash can be seen when the mutated cells located at the outside of plant tissue. But it cannot be seen when the mutated cells located deep inside the plant part.)Viral Splash: Come and go, and reappear (but reappear at random location)
(depend on the activity of virus and environmental conditions. FrMV resides in infected plant throughout the plant's life; therefore, the symptom will reappear when the condition is right.)7. Irregular petal edges
Natural Splash: No
(All are identical type of cells that have the same rate of growth)Natural Splash: No
Chimeral Splash: Yes
(The growth rate (cell division) of mutated cells is inferior to that of normal cells. As a result, the irregular (fringed) edges on flowers' petals are formed.)Viral Splash: No
(it is nothing to do with the rate of cell division or growth)8. Vegetative Propagation (e.g. cutting)
Natural Splash: Yes
Natural Splash: Yes
Chimeral Splash: Yes for Periclinal chimera plant
Viral Splash: N/A (Cuttings taken from an infected plant are also infected.)
9. Seed Transmission
Natural Splash: Natural splash is a result of gene expression. It is variegation typical of cultivars/species, and it is a characteristic that a plant can randomly pass on to its off springs through its genes.
Natural Splash: Natural splash is a result of gene expression. It is variegation typical of cultivars/species, and it is a characteristic that a plant can randomly pass on to its off springs through its genes.
Chimeral Splash: This type of chimera cannot be seed propagated. As chimera occurs in apical cell layers, chimera variegation is not variegation typical of cultivars/species, and cannot pass on to its off spring.
Viral Splash: FrMV does not transmit through seed, resulting in absence of virus in seedlings.
10. Infectability
Natural Splash: No
Natural Splash: No
Chimeral Splash: No
Viral Splash: Yes (by mechanical means via sap)
11. Occurrence
Natural Splash: Rare (seen in some cultivars)
Natural Splash: Rare (seen in some cultivars)
Chimeral Splash: Very rare
Viral Splash: Rare in nature but commonly seen in cultivation
(Spread has occurred through the use of virus-infected cutting tools during propagation. The distribution of virus-infected materials (e.g. cuttings and grafts) in international trade has made the matters worse.)