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Da se zna... Kao uzrok se pominju i virusna infekcija i genetska mutacija. :zbunjen:

Variegated Palms
Variegated palm trees are defined as palms with yellow or white striping on the leaves, and sometimes stems, caused by a viral infection or genetic hybridization.  For the most discerning collectors, variegated palms are the pot of gold at the end of the rainbow.  Some, like variegated Lady Palms (Rhapis sp.), have been propagated (reproduced) and grown for hundreds of years and there are hundreds of types of “registered” cultivars (sub species) in the world, with some fetching prices of up to $20,000 for one plant.  Others, like Watermelon Flame Thrower Palm (Chambeyronia macrocarpa var. watermelon), have a variegated stem but no striping on the leaves (right picture).  Most collectors are drawn to variegated palms due to their rarity and beauty, while most average home-owners are turned off by them due to their “sick” look of having yellow or white striping.  This is sometimes confused with nutrient deficiencies by those who don’t understand or appreciate their value and beauty.  Variegated cycads (cycads are plants which are closely related to palms) are even more difficult to find.  Most variegated palms and cycads fetch prices of $100 to $10,000 each on the open market.
Variegation in palm trees is not always stable.  Many palms will produce one leaf with one stripe on it during its life.  This does not designate it as a “variegated palm”, but likely represents a brief stage of trauma or viral defect in the palm.  Conversely, true variegated palms will show striping on many leaves.  This striping does not go away with age and can sometimes be seen on the stem or crownshaft (neck) as well.  If the palm has a clumping habit (produces several stems from the original stem), the variegation is usually seen in different amounts on each stem.  Whereas, if the palm is a solitary species (only has one stem), the variegation is only seen on the main stem but may be passed on to future offspring if the palm produces seed. 
Like all palm trees, variegated palms reproduce by seed or by clumping.  Seed collected from a variegated palm will grow into variegated offspring at different percentages.  For example, seed from a variegated Clustering Fishtail Palm (Caryota mitis) (left picture) typically germinates with 20% of its offspring becoming variegated like the mother, while seed from a variegated Cabbage Palm (Sabal palmetto) may only germinate with 0.05% of its offspring becoming variegated.  Hence, the variegated Cabbage Palm is usually more valuable than the variegated Clustering Fishtail Palm. 
Variegated clustering palms such as Chamaedorea, Rhapis, Cyrtoctachys, and Caryota mitis can be propagated by dividing each of the stems of the main plant.  If done correctly, each stem will grow as a new plant and will begin clustering itself.  This feature can make these palms more valuable to the nurseryman or collector because the palms can be separated and made into new plants indefinitely.  It may take several years for a solitary-stemmed palm to produce seed to grow into more variegated palms.  This makes solitary-stemmed palms more valuable in general.
Causes of Variegation
Variegation can be either viral or genetic.  Most variegated palms have a viral infection that causes blockages in the chlorophyll.  This viral infection is somewhat similar to albino people who have pale skin or problems with the pigment in their skin that causes white blotches.  No matter how many nutrients albino people eat or how much they try to tan their skin, the pale blotches will remain.  This is much like variegated palms which must be kept in shade otherwise the lighter striping on the leaves may get burned by direct sunlight.  As such, most variegated palms must be grown indoors or in the shade, with the exception being the variegated Clustering Fishtail Palm, which thrives in full sun. 
Genetic variegation can be seen in the Foxy Lady Hybrid (Wodyetia x Veitchia) (right picture) and other intergeneric hybrids (hybrids between two different genus).  In this case, two palm species with similar chromosome counts are hybridized to make a new palm species.  In order for this to happen, both palms must have a similar number of chromosomes within their cellular makeup.  For example, a fan palm from the Mexican desert will not hybridize with a fishtail palm from China.  But, a Dypsis sp. from Madagascar will easily hybridize with another similar-looking Dypsis sp. from the same region.  When two similar palms are hybridized, the resulting plant will have the characteristics of both parents and will sometimes produce chimeras.  In this case, the hybrid palm is composed of two different types of cells- one type from the mother and one from the father.  These cells can “group together” in the stem and leaves which separates the chlorophyll, creating streaks of dark green and separate streaks of yellow or white.  Only the green streaks will draw in sunlight and photosynthesize.  The yellow or white streaks do not provide any nutrients to the plant, and, because of their lack of energy-producing cells, will burn if placed in direct sunlight.  Thus, a heavily-variegated palm tree (mostly yellow or white) will grow much slower and not get as large as a lightly-variegated palm tree that has minimal striping.  In the most basic terms, all variegated palms are “sick” and will grow much slower than their normal siblings.
Albino Palms
Many growers who germinate thousands of seeds at once notice that some come up pure white.  These white seedlings are known as “albino”.  Albino seedlings are mutations that never produce any chlorophyll- this causes them to appear completely white.  These seedlings will grow until the nutrient reserves contained in the seed are completely used up, which means they usually don't grow beyond their eophyll (first leaf).  Do not confuse these with variegated seedlings, which have green stripes.

I ovde se pominje S.palmetto variegata:
Evo sta kazu na PalmTalku za Rhapis excelsu 'Variegata'
Varijacije Rhapis exelese:
Oglasi gde se prodaju sve te variegated-ovane palme:

Sve je to lijepo i krasno.Nitko nije rekao da to nije prirodno,i virus je proroda.Meni se osobno neke vrste u šatiranom obliku sviđaju a neke ne,ono što mi se kod većine nesviđa jest to da su ti bijeli dijelovi manje otporni na sunce a i na led.Nakon ovih zadnjih smrzavanja vidio sam jedan grm filomentose čiji je jedan dio bio variegata,nepravilno,samo taj dio je led spržio,na drugom mjestu agava variegata sa stotinjak maladica oko sebe,sve su bile neoštećene osim jedne koja je na svojim listovima ima klorofila niti 5% u odnosu na druge,nju je totalno spržilo,isto sam je izvadio,možda je srce još živo.Pogledaj onu likualu na onim slikama koje si stavio,i ona ima oštećenja vjerojatno ožegline od sunca.Imam i jedan oleander nepravilno šatiran,i on isto redovno dobija ožegline od sunca na listovima koji su većim dijelom bijeli,kao i ona kadulja,a imam i jednu mirtu istog oblika koja isto tako baca dijelom listove koji su potpuno bijeli te dobijaju ožegline od sunca,dakle biljke čisti heliofiti koji ne trpe sunce,nije normalno.Variegata je prirodna ali nije za biljke poželjna,bar ne za biljke sunca.

Evo jedna maslina variegata, i na njoj se vide oštećenja od leda

  co to juka, dracena :misli:


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