Physiological studies of the halophyte Salicornia bigelovii: A potential food and biofuel crop for integrated aquaculture-agriculture systems.

摘要

It has been demonstrated the technical feasibility of using seawater and other saline water for irrigation. Through the use of saline water for irrigation, highly salt-tolerant crops could greatly increase global agriculture. Brackish water and seawater from different sources are available in areas suitable for production of salt-tolerant crops. Dwarf glasswort Salicornia bigelovii Torr. (Chenopodiaceae), is a leafless, succulent, small-seeded, annual saltmarsh plant, with potential as a saline water crop. It is also a potential oilseed, forage, biomass crop, and a promising carbon sequestration plant. In the first chapter of this document we describe a study where we grew Salicornia bigelovii from seedlings, in saline, drying soils in a greenhouse experiment. The effects of drought and salinity stress were additive. Optimal growth and water use efficiency coincided at 0.35-0.53 M NaCl. The plants were tolerant of high salinity but exhibited little drought tolerance. Salicornia bigelovii plants varied little in their uptake of Na+ for osmotic adjustment, with final Na+ contents of 18% on a dry mass basis. Both growth and water use efficiency of Salicornia bigelovii were affected by salinity. Also, Na+, the primary cation involved in osmotic adjustment of this species, apparently stimulates growth by mechanisms apart from its role as an osmoticum. In the second chapter of this dissertation we developed a research study where we evaluated the production and osmotic adjustment of two S. bigelovii lines (Texas and Florida), plants were grown in pot in a green house and irrigated with water treated with three different levels of NaCl (5 ppt, 15 ppt and 30 ppt) combined with inorganic fertilizer. At the end of the experiment sixty plants from each line were measured for height, biomass, seed yield, seed size, dry matter yield, and tissue osmolarity. There was no significant difference among groups in plant height, or final biomass either in salinity irrigation treatments, or S. bigelovii lines. Tissue osmolarity differed among salinity treatments but not among S. bigelovii lines. The highest tissue osmolarity value was 1192 mM kg-1 found at the treatment 30ppt in the Florida line. Total biomass production was 12 000 kg/Ha.