ARS | Publication request: Mineral nutrition, growth, and germination of Antirrhinum majus L. (snapdragon) when produced under increasingly saline conditions

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 5, 2008
Publication Date: May 30, 2008
Citation: Carter, C.T., Grieve, C.M. 2008. Mineral nutrition, growth, and germination of Antirrhinum majus L. (snapdragon) when produced under increasingly saline conditions. HortScience. Vol 43(3): 710-718

Interpretive Summary: Competition among agricultural and urban users for high-quality water supplies has increased as the population has increased. One environmentally-sound approach for conserving these dwindling water resources is the capture and reuse of degraded, often saline, wastewaters for crop production. Growers of high value cut flower crops have traditionally used high-quality waters in order to avoid jeopardizing quality and yield of the marketable product. However, little quantitative information is available in the literature that would guide growers in the selection of cut flower species which could be produced with recycled, saline waters. This report describes the response of snapdragon (Antirrhinum major, cultivars `Monaco Rose¿ and `Apollo Cinnamon¿) to irrigation with saline waters differing in ion composition. Type A was typical of saline tailwaters present in the inland valleys of California and essentially represents concentrations of Colorado River water. Type B mimicked coastal well waters contaminated by seawater. Five saline treatments were imposed for each water type with electrical conductivities (EC)of 2, 5, 6, 11 and 14 dS m-1. Quality of flowering stems were evaluated on stem and inflorescence length, weight, and diameter, number of flowers per stalk. We used the market quality scale developed for snapdragon by the Society of American Florists. The study revealed that commercially acceptable flowers can be produced using saline water for irrigation. Overall rating for `Monaco¿ stems grown at all salinity levels and both water types was `Special¿ (highest grade). ¿Apollo¿ was rated as `Special¿ grown at salinity levels up to 8 dS m-1. However, quality was reduced slightly to `Fancy¿ as salinity increased to 14 dS m-1.

Technical Abstract: The conservation of quality water is of special concern, especially in California, as the need for quality water increases with a growing population. Reusing saline wastewaters to irrigate salt tolerant floral crops provides a viable option to produce quality marketable cut-flowers while conserving the highest quality water for other purposes. A completely randomized design with three replications was used to investigate the effects of five salinity treatments (2.5 (control), 5, 8, 11, 14 dS m-1) and two water ionic compositions (Colorado River water and sea water) on the mineral uptake, germination, growth, and quality of two cultivars of Antirrhinum majus (¿Monaco Rose¿ and ¿Apollo Cinnamon¿). Seeds of both cultivars were sown in 30 greenhouse sand tanks. Leaves were collected two months after planting and analyzed for concentrations of Ca2+, Mg2+, Na+, Cl-, K+, total-P, and total-S. As salinity increased, Ca2+, Mg2+, Na+, Cl-, and total-S increase in plant tissues whereas K+ and total-P decreased in plant tissues for both cultivars in both irrigation solutions. Leaf nutrient composition was related to the interactions of ions within the substrate solutions and their ability to compete for uptake at the site of root membranes. Phenotypic measurements, made when plants were harvested, showed only slight decreases as salinity increased. Quality of the flowering stems were rated according to standards developed by the Society of American Florists. Marketable stems of both cultivars were produced in all treatments. Overall, quality of stems produced with saline waters ranging from 2.5 to 11 dS m-1 was very high (¿Special¿). Irrigation with more saline water (14 dS m-1) resulted in a slight reduction in quality and stems were rated as ¿Fancy¿ depending on the cultivar. Snapdragons can be produced from seed when exposed to salinities up to 14 dS m-1 using both sea water and Colorado River water ionic solutions for irrigation since germination remained at 92% or greater. Both cut flower cultivars can be produced for commercial use under saline conditions up to at least 14 dS m-1.