SALT TOLERANCE WITHIN A TYPHA POPULATION

Mc Millan , Calvin . (U. Texas, Austin.) Salt tolerance within a Typha population. Amer. Jour. Bot. 46(7): 521–526. Illus. 1959.—Typha in a disturbed salt flat near Lincoln, Nebraska, provided material for an examination of population dynamics. Within the population, clones of T. angustifolia L. tended to occupy the drier sites and those of T. latifolia L. occupied the sites of greater moisture probability. Clones of intermediate morphological characteristics were distributed with both T. angustifolia and T. latifolia. Rhizomes taken from the clones were grown in various NaCl solutions in the greenhouse. Results indicated greatest salt tolerance by T. angustifolia and least salt tolerance by T. latifolia. The intermediate, probably hybrid, clones were intermediate in salt tolerance. Seeds of the 3 clone-types germinated over the same range of salt concentration. The seeds of all 3 types withstood 4 months submergence in a 2% salt solution and germinated upon being returned to tap water. In the salt flat habitat, the clones of T. latifolia were not vigorous during the years 1956–1957 and many died or were reduced considerably in area of occupancy. The clones of T. angustifolia remained vigorous and flowered over the same period. The intermediate clones were vigorous and increased their coverage, primarily in areas that were occupied prior to 1956 by T. latifolia. The spatial adjustments within the population probably resulted from the selective action of increased salt concentration accompanying the drier conditions of 1956 and 1957.