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- Author or Editor: Judy Harrington x
Distichlis spicata var. stricta (Torrey) Beetle is a native grass that tolerates salt, high pH, and some heavy metals. It has been proposed for use in several challenging environments, including mine spoils and salt-impacted areas of golf courses, but its widespread use has been hindered by several factors, one of which is seed dormancy. Dormancy appears to be coat-imposed and can be overcome by scarification in relatively young seed lots. Thirteen-year-old seeds germinated better without scarification. Seeds were tested at several constant and alternating temperatures. Temperatures around 30 °C seemed to give the highest percentage germination, approaching the viability that was shown by tetrazolium chloride tests for each seed lot. Alternating temperatures increased the germination of unscarified seeds but not as much as scarification did. Light appears to be unnecessary for germination.
Distichlis spicata var. stricta (Torrey) Beetle is a native grass that tolerates salt, high pH, and some heavy metals. It has been proposed for use in several challenging environments, including mine spoils and salt-impacted areas of golf courses. But, its widespread use has been hindered by several factors, one of which is poor seed set. Because chromosome numbers are variable and some genotypes are aneuploids, there was concern that pollen viability in some genotypes was low. Pollen from several genotypes failed to germinate in vitro on four artificial media prepared with various levels of osmoticum. However, hand pollination in vivo resulted in profuse pollen germination for all genotypes tested. Germination on pollinated stigmas was observed at intervals beginning 2 h after pollination with a fluorescence microscope using aniline blue and acridine orange stains and in bright field using toluidine-O stain. Very young stigmas seemed unreceptive and, while pollen would germinate, the pollen tubes would not grow down through the style. On receptive stigmas, many pollen tubes grew down toward the egg and some reached it within 24 h. There was no evidence of impaired fertility. Aniline blue was the best method for observing pollen tube growth through the style, although toluidine-O was adequate for observing germination on the stigmatic surface.
Inland saltgrass, Distichlis spicata var. stricta (Torr.) Beetle, is a native western U.S. grass that has potential in turf situations. Elite clones with outstanding potential have been selected. Poor seed production appears to be the main limiting factor for its use as turf in saline conditions. In order to better understand seed set, 40 genotypes were examined for chromosome number and morphology. Chromosome numbers of root tip metaphase spreads varied with the most common being 2n = 38. However, chromosome numbers of 39, 40, 42, and 74 were also observed. Meiotic examination of anthers revealed 19 bivalents for those with 38 chromosomes while those with 42 had 20 bivalents with 2 unpaired chromosomes. The unpaired chromosomes lagged at anaphase. Crosses among genotypes of different chromosome number have resulted in good seed set. Harvested seed are germinable and plants from these crosses are being grown for further studies.