''Rhododendron album'' is a species of

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...

in the family Ericaceae. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's List ...

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...

. It is a

vulnerable species A vulnerable species is a species which has been Conservation status, categorized by the International Union for Conservation of Nature as being threatened species, threatened with extinction unless the circumstances that are threatened species, ...

threatened by

habitat loss Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

Description

''Rhododendron album'' is white, but can also appear lilac, depending on the

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two dif ...

. The stamen is often a different color, such as orange or pink. The flower is four to six inches high, and blooms in the spring, staying green throughout autumn. (Bay Science Foundation, 2008) In 1998, ''Rhododendron album'' was deemed vulnerable by the World Conservation Monitoring Centre, meaning that it faces a high risk of extinction in the mid-term future unless proper

conservation Conservation is the preservation or efficient use of resources, or the conservation of various quantities under physical laws. Conservation may also refer to: Environment and natural resources * Nature conservation, the protection and manageme ...

methods are employed (Whitten et al. 1996). ''Rhododendron album'' is native to

(Indonesian Jawa),

. It is mostly found in the increasingly smaller high elevation forests throughout western and central Java.

Threats

Habitat loss

''Rhododendron album'' is threatened by

. The habitat loss is due to

agriculture Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to ...

, extraction of trees and other species of plants, as well as expansion of

infrastructure Infrastructure is the set of facilities and systems that serve a country, city, or other area, and encompasses the services and facilities necessary for its economy, households and firms to function. Infrastructure is composed of public and priv ...

throughout Java’s forests. The degradation of Java’s forests is more intense in lower elevations, but higher elevations where the plant grows are also affected. (Whitten et al. 1996). Most of Java’s forests have been cleared, and what is left is generally located in mountainous areas. The forests are legally protected, although locals continue to extract trees for timber and firewood, and many depend on the trees for their livelihood. Tree cutting in many places in Java has changed the forest to the point that large parts of former forest are now covered with shrubs, and

forest degradation Forest degradation is a process in which the biological wealth of a forest area is permanently diminished by some factor or by a combination of factors. "This does not involve a reduction of the forest area, but rather a quality decrease in its c ...

, especially as a result of tree cutting, is widespread throughout. (Smiet, 1992). In order to save the species, more education and a stricter enforcement of the law against tree cutting is required. The Indonesian government must also reach an agreement with locals in Java, as the local's livelihoods often depend on the wood from the trees of these forests.

Uses and stakeholders

''Rhododendron album'' is grown widely in nurseries throughout the world, especially in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. Much research has been done developing hybrids with high

aesthetic Aesthetics, or esthetics, is a branch of philosophy that deals with the nature of beauty and taste, as well as the philosophy of art (its own area of philosophy that comes out of aesthetics). It examines aesthetic values, often expressed th ...

value. One of the earliest hybrids created was the ''Rhododendron cawtawbiense var. album'', known as the ''Catawba album''. It was bred in 1886 by Anthony Waterer, an early hybridizer (Paghat, 2008). Besides maintaining

biodiversity Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic (''genetic variability''), species (''species diversity''), and ecosystem (''ecosystem diversity'') l ...

, ''Rhododendron album'' is important for its aesthetic value. ''Rhododendron album'', along with the many other variations and hybrids, are popular plants in the

landscaping Landscaping refers to any activity that modifies the visible features of an area of land, including the following: # Living elements, such as flora or fauna; or what is commonly called gardening, the art and craft of growing plants with a goal o ...

industry, and are used for a variety of decorations, including wedding and special occasion bouquets, corsages, and other floral arrangements.

Diseases and research

Although nurseries have contributed to the continued survival of the plant, they have not been able to save all of them, and there have been outbreaks of

disease A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...

. These diseases, caused by various

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

and

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...

, have been severe and widespread. ''Pseudomonas cichorii'' In 1995, the bacteria ''

Pseudomonas cichorii ''Pseudomonas cichorii'' is a Gram-negative soil bacterium that is pathogenic to plants. It has a wide host range, and can have an important economical impact on lettuce, celery and chrysanthemum crops. ''P. cichorii'' was first isolated on endi ...

'' was discovered on container-grown rhododendrons in a nursery in Georgia, USA. The spots were at first very small, one to five millimeters in diameter, but soon grew into large, reddish brown blotches. (Uddin & McCarter, 1996). ''Phytophthora ramorum'' In 2002 and 2003, studies in nurseries throughout

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

and

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

tested for '' Phytophthora ramorum''. The symptoms of the disease were large necrotic spots with water soaked outside borders and rust colored centers. Symptomatic plants were collected, and DNA was extracted from the spots. After amplifying it with a PCR assay, GenBank matched the DNA to that of ''Phytophthora ramorum'' and ''P. lateralis''. In 2004, Rhododendron leaves with similar symptoms were studied and showed the host range of P. hibernalis as well (Blomquist et al. 2005). In a test of the susceptibility of five different types of Rhododendron to ''P. ramorum'', samples were exposed to a

zoospore A zoospore is a motile asexual spore that uses a flagellum for locomotion. Also called a swarm spore, these spores are created by some protists, bacteria, and fungi to propagate themselves. Diversity Flagella types Zoospores may possess one or mo ...

suspension and left in a moist environment for 10 days. Measurements taken after the incubation period showed differences in susceptibility between the five types. ''Catawbiense album'', the only variation of R. album used in the study, was found to be more susceptible than three of the other types of rhododendron (McDonalad et al. 2006). Tissue Proliferation Tissue proliferation is another disorder ''Rhododendron album'' has encountered in nurseries. It was first found in the mid-1980s and is characterized by tumor like growths. These growths are usually towards the bottom of the stem, but can be above or below the soil line (Zimmerman, 1997). When first discovered, there was worry among nursery owners and growers. It is now thought that the disease is caused by ''Agrobacterium tumefaciens''. Researchers have been working to isolate the bacteria, and also have asked for help from nurseries and growers in looking for links to possible causes. At least 15 states, along with

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

and the

U.K. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

have reported cases of tissue proliferation (Zimmerman, 1997). Breeding cycle and repopulation Steps are being taken towards saving and repopulating the plant. In 1955, researchers attempted to shorten the breeding cycle of the Rhododendron ''catawbiense album.'' They knew that if dormant buds of ''R. catawbiense album'' were dormant for too long, they were subject to breakage. They found that when keeping the plants at between 15 and 20 degrees Celsius, the number of growth periods was increased, and the speed of growth in many of the plants was twice that of a natural day. When applied to

seedlings A seedling is a young sporophyte developing out of a plant embryo from a seed. Seedling development starts with germination of the seed. A typical young seedling consists of three main parts: the radicle (embryonic root), the hypocotyl (embry ...

, this treatment cut the time taken to flower in half. (Doorenbos, 1955).

References

* Bay Science Foundation. Rhododendron Album. Revised April 27, 2008 * World Conservation Monitoring Centre, 1998. Rhododendron album. In: IUCN 2007. 2007 IUCN Red List of Threatened Species. . Downloaded on 27 April 2008. * Whitten, T., Soeriaatmadja, R.E. and Afiff, S.A. 1996. The Ecology of Java and Bali. The Ecology of Indonesia Series. Volume III. Periplus Editions, Republic of Singapore. * Alfred C Smiet. Forest ecology on Java: Human Impact and Vegetation of Montane Forest. Journal of Tropical Ecology May 1992 Vol. 8, No 2 p 129-152. * Vincent Nijman, S. (Bas) van Balen (1998) A faunal survey of the Dieng Mountains, Central Java, Indonesia: distribution and conservation of endemic primate taxa Oryx, Volume 32 Issue 2 Page 145-156, April 1998
Paghat, 2008 Paghat’s Garden
Accessed 27 April 2008 * W. Uddin & S. M. McCarter. First Report of Rhododendron Leaf Spot Caused by Pseudomonas cichorii . The American Phytopathological Society, May 30, 1996 * McDonalad, V., Grunwald, N.J., Linderman, R.G. 2006 Evaluation of Infection Potential and Sporulation of Phytophthora ramorum on five Rhododendron Cultivars. Phytopathology. 96:S75. 1 June 2006 * Richard H. Zimmerman. A review of tissue proliferation of Rhododendron. International Symposium on Bacterial and Bacteria-Like Contaminants of Plant Tissue Cultures p 355-356. 1997 * J. Doorenbos. Shortening the breeding cycle of rhododendron. Euphytica Vol. 4 No. 2 July 1955 * Brand M. H; Kiyomoto R. Redevelopment of tissue proliferation symptoms in rooted Rhododendron cuttings. HortScience 1999, vol. 34, no 4, pp. 723–726 * Homer E. Salley & Harold E. Greer. Rhododendron Hybrids 1992 Timber Press p. viii {{Taxonbar, from=Q5463626

album An album is a collection of audio recordings issued on compact disc (CD), Phonograph record, vinyl, audio tape, or another medium such as Digital distribution#Music, digital distribution. Albums of recorded sound were developed in the early ...

Endemic flora of Java Vulnerable plants Taxonomy articles created by Polbot