|Grattan, Stephen - DEPT LAWR, UC DAVIS|
|Lieth, J - DEPT ENV HORT, UC DAVIS|
Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 5, 2004
Publication Date: June 10, 2005
Citation: Grieve, C.M., Poss, J.A., Grattan, S.R., Shouse, P.J., Lieth, J.H., Zeng, L. 2005. Productivity and mineral nutritionof limonium species irrigated with saline wastewaters. Hortscience. 40(3):654-658. Interpretive Summary: Competition between agricultural and urban users for high-quality water supplies has increased as the population has increased. One environmentally-sound approach to the conservation of these dwindling water resources is the 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 yield losses associated with salinity. 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 two commercially valuable cut flower species to irrigation with saline waters prepared to simulate drainage effluents commonly present in the San Joaquin Valley of California. Two species of statice (Limonium perezii, cultivar 'Blue Seas' and L. sinuatum, cultivar 'American Beauty') were grown in greenhouse sand tanks. Seven salinity levels were imposed with electrical conductivities of 2.5, 7, 11, 15, 20, 25, and 30 dS m-1. Both species flowered even at the highest salinity level. However, stem length, an important component for evaluating consumer acceptability, significantly decreased as salinity increased. L. sinuatum proved to be moderately salt tolerant, whereas L. perezii was more salt sensitive. The enhanced ability of L. sinuatum to withstand the challenge of salt stress appeared to be associated with its ability to acquire ions (sodium, potassium, magnesium, phosphorus) from the saline solutions bathing the roots and transport them to the leaves. Two conclusions arise from this study: (1) 'American Beauty' statice will produce a commercially acceptable flower under irrigation with moderately saline water, and (2) both 'American Beauty' and 'Blue Seas' statice produced healthy plants with attractive foliage and colorful inflorescences under severe salt stress and thus have great value as bedding or landscape plants in areas affected by salinity.
Technical Abstract: To explore the possibility that saline wastewaters may be used to grow commercially acceptable floriculture crops, a study was initiated to determine the effects of salinity on two statice cultivars. Limonium perezii (Stapf) F. T. Hubb. cv. 'Blue Seas' and L. sinuatum (L.) Mill cv. 'American Beauty' were grown in greenhouse sand cultures irrigated with waters prepared to simulate saline drainage waters typically present in the western San Joaquin Valley (SJV) of California. Seven salinity treatments were imposed on three-week old seedlings. Electrical conductivities of the irrigation waters (EC) were 2.5 (control), 7, 11, 15, 20, 25, and 30 dS/m. Vegetative shoots were sampled for biomass production and ion analysis ten weeks after application of stress. Numbers, length and weight of flowering stems were determined as the inflorescences matured. Reduction of these yield components by salt stress was greater for L. perezii than for L. sinuatum. The species also exhibited significant differences in shoot-ion relations which appeared to be related to differences in salt tolerance. Sodium, K+, Mg2+, and total-P were more strongly accumulated in the leaves of L. sinuatum than L. perezii. Both species accumulated K+ in preference to Na+, but selectivity for K+ over Na+ was significantly higher in L. sinuatum than in the more salt-sensitive L. perezii. Chloride concentration in L. sinuatum leaves increased significantly as salinity increased, whereas the 20-fold increase in substrate-Cl had no effect on leaf-Cl in L. perezii. Both Limonium species completed their life cycles at salt concentrations exceeding 30 dS/m, a character associated with halophytic plants. Maximum growth of each species, however, occurred under relatively low salt stress, and steadily declined as external salinity increased. Based on this crop productivity response, L. perezii should be rated as sensitive and L. sinuatum as moderately tolerant.