We investigated physiological integration among ramets of Spartina patens when clones spanned a salinity gradient. Clones of S. patens were grown in paired pots with the ramets of the parent pot connected to the ramets of the daughter pot via a common rhizome. Half of these clones had the rhizome connection between parent and daughter pots severed immediately prior to treatment application. The parent pots were kept at low salinity (34.2 mM NaCl) and given two levels of labeled 15NH4Cl (0.036 or 0.714 mM NH4Cl). Daughter ramet pots were kept at the low N level (unlabeled 0.036 mM NH4Cl) and exposed to an increase in salinity to 513 mM NaCl. After 7 days, all daughter ramets had significantly elevated leaf Na levels. Daughter ramets connected to parents were able to maintain significantly greater leaf elongation rates than severed daughter ramets. Labeled 15N was translocated from parents to connected daughter ramets and high-N parents translocated more N to the belowground tissue of daughter ramets than low-N parents. Leaf proline, a nitrogen-containing osmoticum that accumulates only after a threshold of salinity stress is exceeded, was significantly increased only in severed daughter ramets, indicating that salinity stress was reduced in connected daughter ramets, possibly via parental water translocation. Key words: clone, physiological integration, proline, ramet, salt marsh, salt stress.
