In: Phyton 54, Fasc. 1 (2014): S. 101-122 DOI: 10.12905/0380.phytons54(1)2014-0101

Key words: Flooding, free amino acids, Lupinus albus, Leguminosae, membrane stability, salicylic acid, salinity, soluble sugars, waterlogging.

Summary

Sayed S. A. 2014. Ameliorative effects of salicylic acid on salt-stressed Lupinus albus plants growing under oxygen deficiency. – Phyton (Horn, Austria) 54 (1): 101–122, with 7 tables.

Lupinus albus plants , 22 day old, were exposed to wide range of soil water osmotic potential (Ys = 0 to –1.0 MPa) induced by Na Cl and CaCl2 treatments in combination with roots maintained under aerobic (drained at field capacity) or anaerobic (flooded) conditions in the soil, and sprayed with 5 mg l-1 salicylic acid (SA) solution. In drained plants salt stress negatively affected shoot and root growth, leaf relative water content (RWC), chlorophyll (Chl), soluble sugars (SS), soluble proteins (SP), and K+ contents. On the contrary, salinity significantly increased membranes injury by either heat (51 oC ) or dehydration (40% polyethylene glycol, PEG) stress and enhanced the accumulation of total free amino acids (TAA) , Na+, Ca+2 and Cl-. Waterlogging caused an additive reduction in growth, Chl content and leaf RWC but enhanced leaf membranes injury. Both salinity and waterlogging synergize to increase Na+, Ca2+ and Cl- accumulation. Plants treated with salicylic acid often had greater shoot and root dry matter, Chl content as well as higher K+ content. The effects of SA were more pronounced in salt-stressed plants grown under soil oxygen deprivation. Statistical analysis showed that the effects of single factors (soil salinity (Ys), soil waterlogging, (WL) and salicylic acid (SA) and their interactions (Ys × WL, Ys × SA, WL × SA and Ys × WL × SA) were significant for most parameters tested. Calculation of the coefficient of determination (h2) led to three important findings: (1) – salinity (Ys) was dominant in affecting stability of membranes to heat, Chl b stability, soluble proteins, total free amino acids, dry matter, Ca2+, Cl– and Na+ contents. (2) – Salicylic acid had dominant effects on stability of leaf membranes to dehydration stress, Chl a and Chl b, SS, SP, and HS contents. (3) – The share of waterlogging (WL) was dominant for K+ content. Finally it can be concluded that salicylic acid application had an ameliorative effect and helped lupine plants to grow successfully in the areas subjected to combined effects of salinity and oxygen deprivation, such as in salt marshes.