Salinity studies with drought-resistant species of Sporobolus.

Dry matter productivity under saline conditions was compared in 5 desiccation-tolerant "resurrection" grasses and one desiccation sensitive species, all in the genus Sporobolus. S. stapfianus was the most salt tolerant, requiring 215 mole NaCl m-3 to reduce shoot dry matter increments to 50% of increments in plants not treated with salt. (This was comparable to published values for the salt tolerant grass Diplachne fusca.) S. lampranthus was salt sensitive, requiring 35 mol m-3 for 50% control yields. S. festivus, S. aff. Fimbriatus, and the deisccation sensitive S.pyramidalis was moderately tolerant (150-170 mol m-3). The moderate salt resistance of S. aff. fimbriatus was attributed mainly to exclusion of NaCl by roots. Salt export through leaf surfaces was a minor factor. Half of the leaf mesophyll cells survived 50 min immersion in 200 mol NaCl m-3. Plants of S. aff. fimbriatus and S. pyramidalis tolerated a broad range of soil pH. Plants of 4 desiccation tolerant Sporobolus species survived air-dryness following 3 weeks pretreatment with salinities up to 200 mol m-3.