Recommendations for Maintaining Postharvest Quality
Michael S. Reid and Linda Dodge
Department of Environmental Horticulture, University of California, Davis, CA 95616
The elegant blooms of this tropical aroid are produced and sold throughout the world. The true flowers are found on the “spadix”, the upright organ in the center of the “spathe”, which is the decorative petal-like organ surrounding the spadix. Although anthuriums are sensitive to low temperatures, they have a long vase life when properly handled. The end of their vase life is usually the result of inability to draw water from the vase solution, and is associated with loss of glossiness and then blueing of the spathe. Most of the water lost by the flower evaporates from the spadix. Application of wax, to prevent this water loss, or pulsing with silver nitrate, to improve water relations of the flower, can extend their vase life considerably.
The proportion of open flowers on the spadix determines the maturity of anthurium flowers. In immature anthuriums, the spadix is smooth. Flower opening starts at the base of the spadix and proceeds upwards; spadices with open flowers are noticeably rough. Although producers in some countries harvest anthuriums when as little as 20% (1/5) of the spadix is rough, Hawaiian growers harvest flowers when only 1/4 of the spadix is still smooth (3/4 of the flowers are therefore open). Harvesting anthuriums when more mature increases overall vase life.
The flowers are removed from the plant using shears.
Although there are no formal grade standards for anthuriums, top quality implies long stems, uniformity of color and size, proper maturity, glossiness of the spathe, and freedom from any damage or disease.
Hawaiian researchers recommend pretreatment to increase the vase life of anthuriums, but we have found that some cultivars (e.g. ‘Osaki’) achieve maximum vase life with dionized water (DI) alone. The pre-treatments suggested are:
Pulse the re-cut stems
for 10 to 20 minutes in 1000 ppm silver nitrate. (Rinse the stems with fresh water after the treatment), OR
Dip the whole flower
in an emulsion of Carnuba wax. One suitable product is FMC Wax 819. Use a 3% dilution of the wax. After dipping, place the flower stems in water while the wax dries.
Pre-treated flowers are not harmed by vase preservatives but derive no additional benefit from them. Anthuriums can have a vase life of up to 3 weeks if properly treated. Even after a week of storage, vase life can be adequate, if proper techniques are used to handle the flowers. It seems reasonable that vase life problems are associated with bacterial contamination of the cut stem bases. If anthuriums are placed in water after harvest, a biocide (e.g. 50 ppm hypochlorite) should be added.
Anthuriums are normally packaged individually. They are commonly packed in moist shredded newsprint or other shredded paper. Major damage during transportation is the result of spadices puncturing the spathe of neighboring flowers in the pack. Many producers now sheathe the flowers in small plastic bags and pack the anthuriums more densely in the box.
Anthuriums are very sensitive to “chilling” injury. Holding the flowers for any length of time at temperatures below 10° C (50° F) will induce purpling, browning, and then necrosis. Anthuriums should therefore never be pre-cooled with other flowers, nor held in low temperature cool-rooms.
Anthuriums shipped in mixed loads at low temperatures should be protected from chilling exposure by appropriate insulation (for example wrapping the flowers in newsprint and packing them in an insulated box). Anthurium flowers can be stored for at least one week if packed in moist shredded newsprint and held at 16° C (60° F).
Based on the lack of response of these flowers to treatment with STS, it appears that they are not particularly sensitive to ethylene.
Rates of Respiration
Remain to be determined.
Response to CA
Anthuriums respond favorably to storage in a controlled atmosphere. Vase life was increased by 50% when flowers were stored in air at 13° C (55° F) or in 2% oxygen at room temperature for up to 2 weeks.
Since even brief storage at temperatures below 10° C (50° F) results in chilling injury, freezing injury is not a major issue. Temperatures below –0.5° (23° F) will result in freezing injury – water soaking of the spathe, and collapse of the spadix.
Postharvest Technology Research and Information Center
Department of Pomology
University of California
One Shields Ave., Davis, CA 95616-8683Send comments and questions to Postharvest Technology Research and Information Center
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Produce/ProduceFacts/Veg/anthu.html updated July 12, 2000